Removable fully covered self-expandable metal stents in the treatment of common bile duct strictures due to chronic pancreatitis: a case series

NARCIS (Netherlands)

Cahen, D. L.; Rauws, E. A.; Gouma, D. J.; Fockens, P.; Bruno, M. J.

2008-01-01

The aim of this study was to test the removability of fully covered self-expandable metal stents (FCSEMS) in patients with a benign common bile duct (CBD) stricture. A FCSEMS was inserted in six patients with a CBD stricture due to chronic pancreatitis who were considered to be unfit for surgery,

Safety and efficacy of a fully covered large-diameter self-expanding metal stent for the treatment of upper gastrointestinal perforations, anastomotic leaks, and fistula

NARCIS (Netherlands)

van den Berg, M. W.; Kerbert, A. C.; van Soest, E. J.; Schwartz, M. P.; Bakker, C. M.; Gilissen, L. P. L.; van Hooft, J. E.

2016-01-01

Upper gastrointestinal perforations, fistula, and anastomotic leaks are severe conditions with high mortality. Temporary endoscopic placement of fully covered self-expanding metal stent (fSEMS) has emerged as treatment option. Stent migration is a major drawback of currently used stents. Migration

Clinical Outcomes of Self-Expandable Metal Stents for Malignant Rectal Obstruction.

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Lee, Hyun Jung; Hong, Sung Pil; Cheon, Jae Hee; Kim, Tae Il; Kim, Won Ho; Park, Soo Jung

2018-01-01

Self-expandable metal stents are widely used to treat malignant colorectal obstruction. However, data on clinical outcomes of stent placement for rectal obstruction specifically are lacking. We aimed to investigate the clinical outcomes of self-expandable metal stents in malignant rectal obstruction in comparison with those in left colonic obstruction and to identify factors associated with clinical failure and complication. This was a retrospective study. The study was conducted at a tertiary care center. Between January 2005 and December 2013, medical charts of patients who underwent stent placement for malignant rectal or left colonic obstruction were reviewed retrospectively. Study intervention included self-expandable metal stent placement. Technical success, clinical success, and complications were measured. Technical success rates for the 2 study groups (rectum vs left colon, 93.5% vs 93.1%; p = 0.86) did not differ significantly; however, the clinical success rate was lower in patients with rectal obstruction (85.4% vs 92.1%; p = 0.02). In addition, the complication rate was higher in patients with rectal obstruction (37.4% vs 25.1%; p = 0.01). Patients with rectal obstruction showed higher rates of obstruction because of extracolonic malignancy (33.8% vs 15.8%; p stent use for palliation (78.6% vs 56.3%; p stent usage to be independent risk factors for clinical failure. Factors predictive of complications in the palliative group were total obstruction, obstruction because of extracolonic malignancy, and covered stent usage. This was a retrospective, single-center study. The efficacy and safety of stent placement for malignant rectal obstruction were comparable with those for left colonic obstruction. However, obstruction attributed to extracolonic malignancy, use of covered stents, and total obstruction negatively impacted clinical outcomes of self-expandable metal stent placement and must be considered by endoscopists. See Video Abstract at http

Self-Expandable Metallic Stent Placement for the Palliation of Esophageal Cancer.

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Kim, Kun Yung; Tsauo, Jiaywei; Song, Ho Young; Kim, Pyeong Hwa; Park, Jung Hoon

2017-07-01

Esophageal stents have been used to palliate patients with dysphagia caused by esophageal cancer. Early rigid plastic prostheses have been associated with a high risk of complications. However, with the development of self-expanding stents, it has developed into a widely accepted method for treating malignant esophageal strictures and esophagorespiratory fistulas (ERFs). The present review covers various aspects of self-expanding metallic stent placement for palliating esophageal cancer, including its types, placement procedures, indications, contraindications, complications, and some of innovations that will become available in the future. © 2017 The Korean Academy of Medical Sciences.

[Clinical application of a fully covered self-expandable metallic stent in treatment of airway fistula].

Science.gov (United States)

Zhu, Qiang; Zang, Qi; Jiang, Zhong-min; Wang, Wei; Cao, Ming

2013-06-01

To assess the feasibility, safety and efficacy of the use of a fully covered self-expandable stent for the treatment of airway fistula. From August 2005 to November 2011, 9 patients underwent treatment by the introduction of a tracheo-bronchial or bronchial fully covered self-expandable metallic stent. There were 7 males and 2 females, aged from 28-65 years with a mean of 46 years. In this group, 7 cases were diagnosed as bronchopleural fistula, 1 case as tracheopleural fistula, 1 case as broncho-esophageal fistula, 8 cases with thoracic empyema. The fistula orifices were from 3.5-25.0 mm in diameter with a mean 8.4 mm. All patients received topical anesthesia, and L-shaped stent was placed in 6 patients and I-shaped stent in 3 patients under fluoroscopic guidance. After the stent placement, the patients with empyema were treated with continual irrigation of the empyema cavity. Stent placement in the tracheo-bronchial tree was technically successful in all patients, without procedure-related complications. The operating time was from 5-16 minutes, mean time (10 ± 4) minutes. Except for 1 patient, immediate closure of the airway fistula was achieved in the other patients after the procedure, as shown by the immediate cessation of bubbling in the chest drain system or the contrast examination. In this study, 1 patient coughed the inserted stent out due to irritable cough on the 5th day and had to receive repositioning of a new stent. Among the patients who were with empyema, 1 patient died of septicemia on the 8th day and 1 patient died of brain metastases from lung cancer 6 months after the stent insertion with empyema not cured, the other 6 patients' empyema healed from 2-5 months, mean time 3.7 months. Seven patients were followed from 3 to 36 months with a median of 13.5 months. During follow-up, 1 stent was removed from a patient 8 months after the stent implantation without empyema recurred. The remaining patient presented good tolerability to the existence of

Esophageal carcinoma treatment with self-expanding covered stent implanted in esophagus

International Nuclear Information System (INIS)

Liu Mingguo; Ji Yan; He Nengwei

2006-01-01

Objective: To investigate the clinical significance of the treatment to esophageal cancer by self- expanding covered stent implanted into esophagus. Methods: Under fluoroscopic guidance and with guidance wire , 20 self-expanding covered stents were implanted into stenotic part of esophagus to recanalize the esophagus, then follow up to observe the clinical symptom improved. Results: Technical success was obtained 20 cases without any complication. Clinical symptom were improved in shot time. Conclusions: self-expanding covered stent is implanted in stenotic part of esophageal carcinoma to treat esophageal stenosis and enable to improved clinical symptom in shot time, if combined with transcatheter arterial infusion and embolization, Radiotherapy, Chinese medical treatment, it enable to lengthen life time remarkably. (authors)

Use of covered self-expandable stents for benign colorectal disorders in children.

Science.gov (United States)

Lange, Bettina; Sold, Moritz; Kähler, Georg; Wessel, Lucas M; Kubiak, Rainer

2017-01-01

There is a lack of experience with covered self-expandable stents for benign colorectal disorders in children. Five children (4M, 1F) with a median age of 5years (range, 6months-9years) who underwent treatment with covered self-expandable plastic (SEPSs) or self-expandable metal stents (SEMSs) for a benign colorectal condition between April 2005 and November 2013 were recruited to this retrospective study. Etiologies included: anastomotic stricture with (n=1) or without (n=3) simultaneous enterocutaneous fistula, as well as an anastomotic leak associated with enterocutaneous fistula (n=1). All children suffered from either Hirschsprung's disease (n=3) or total colonic aganglionosis (Zuelzer-Wilson syndrome) (n=2). Median duration of individual stent placement was 23days (range, 1-87days). In all cases up to five different stents were placed over time. At follow-up two patients were successfully treated without further intervention. In another patient the anastomotic stricture resolved fully, but a coexisting enterocutaneous fistula persisted. Overall, three patients did not improve completely following stenting and required definite surgery. Stent-related problems were noted in all cases. There was one perforation of the colon at stent insertion. Further complications consisted of stent dislocation (n=4), obstruction (n=1), formation of granulation tissue (n=1), ulceration (n=1) and discomfort (n=3). Covered self-expandable stents enrich the armamentarium of interventions for benign colorectal disorders in children including anastomotic strictures and intestinal leaks. A stent can be applied either as an emergency procedure (bridge to surgery) or as an adjuvant treatment further to endoscopy and dilatation. Postinterventional problems are frequent but there is a potential for temporary or definite improvement following stent insertion. Copyright © 2017. Published by Elsevier Inc.

A Novel Partially Covered Self-Expandable Metallic Stent with Proximal Flare in Patients with Malignant Gastric Outlet Obstruction.

Science.gov (United States)

Takahara, Naminatsu; Isayama, Hiroyuki; Nakai, Yousuke; Yoshida, Shuntaro; Saito, Tomotaka; Mizuno, Suguru; Yagioka, Hiroshi; Kogure, Hirofumi; Togawa, Osamu; Matsubara, Saburo; Ito, Yukiko; Yamamoto, Natsuyo; Tada, Minoru; Koike, Kazuhiko

2017-07-15

Endoscopic placement of self-expandable metal stents (SEMSs) has emerged as a palliative treatment for malignant gastric outlet obstruction (GOO). Although covered SEMSs can prevent tumor ingrowth, frequent migration of covered SEMSs may offset their advantages in preventing tumor ingrowth. We conducted this multicenter, single-arm, retrospective study at six tertiary referral centers to evaluate the safety and efficacy of a partially covered SEMS with an uncovered large-bore flare at the proximal end as an antimigration system in 41 patients with symptomatic malignant GOO. The primary outcome was clinical success, and the secondary outcomes were technical success, stent dysfunction, adverse events, and survival after stent placement. The technical and clinical success rates were 100% and 95%, respectively. Stent dysfunctions occurred in 17 patients (41%), including stent migration in nine (23%), tumor ingrowth in one (2%), and tumor overgrowth in four (10%). Two patients (5%) developed adverse events: one pancreatitis and one perforation. No procedure-related death was observed. A novel partially covered SEMS with a large-bore flare proximal end was safe and effective for malignant GOO but failed to prevent stent migration. Further research is warranted to develop a covered SEMS with an optimal antimigration system.

Fully covered self-expanding metal stents are effective for benign esophagogastric disruptions and strictures.

Science.gov (United States)

Wilson, Jennifer L; Louie, Brian E; Farivar, Alexander S; Vallières, Eric; Aye, Ralph W

2013-12-01

Self-expanding fully covered metal stents (CSs) are ideal for use in benign esophagogastric disease. We reviewed our experience with CS to evaluate outcomes, to determine a role for CS in a standard treatment for benign esophageal conditions, and to compare our results with recently published studies. We performed a retrospective chart review from 2005 to 2012. A total of 57 CSs were placed in 44 patients. Indications were stricture (11 patients), anastomotic leak (20), perforation (7), and tracheoesophageal fistulae (6). For GI tract disruptions, open repair or diversion was avoided in 31/33 patients (93.9 %) but required an associated drainage procedure in 22/33 (67 %) patients. Resolution does not depend on achieving radiological control with 6/26 (23 %) having evidence of a persistent leak. Benign strictures were dilated at a mean of 3.7 times prior to stenting. Adjunctive intra-mucosal steroid injections were used in 8/11 patients. Stents were removed at a mean of 33 days. At a mean of 283 days of follow-up, 6/11 (54.5 %) had symptom resolution. The most common complication was stent migration occurring in 17.5 % of patients overall. Covered stents are an effective adjunct in the management of benign upper gastrointestinal tract fistulae, leaks, perforations and benign strictures.

Functional Self-Expandable Metal Stents in Biliary Obstruction

Science.gov (United States)

Kwon, Chang-Il; Ko, Kwang Hyun; Hahm, Ki Baik

2013-01-01

Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories. PMID:24143314

Removal of self expandable metallic airway stent: A rare case report

OpenAIRE

Chawla, Rakesh K.; Madan, Arun; Singh, Ishwar; Mudoiya, Rahul; Chawla, Aditya; Gupta, Radha; Chawla, Kiran; Chhabra, Roopam

2013-01-01

Covered self expandable metallic airway stents (SEMS) have been used for benign tracheal stenosis, post intubation tracheal stenosis, tracheal burn or trauma, tracheo-broncho-malacia, and extrinsic compression of trachea. Their placement is considered to be permanent, with open surgery the only way to remove the stent, though there are few cases reports of their removal with the bronchoscope, but the complications after their removal are very high. In our patient, one and a half years after p...

Treatment of esophagopleural fistulas using covered retrievable expandable metallic stents.

Science.gov (United States)

Kim, Tae-Hyung; Shin, Ji Hoon; Kim, Kyung Rae; Park, Jung-Hoon; Kim, Jin Hyoung; Song, Ho-Young

2014-04-01

To evaluate the clinical efficacy of placement of covered retrievable expandable metallic stents for esophagopleural fistulas (EPFs). During the period 1997-2013, nine patients with EPF were treated using covered retrievable expandable metallic stents. The underlying causes of EPF were esophageal carcinoma (n = 6), lung cancer (n = 2), and postoperative empyema for Boerhaave syndrome (n = 1). Technical success was achieved in eight patients (88.9%). In one patient, incomplete EPF closure was due to incomplete stent expansion. Clinical success, defined as complete EPF closure within 7 days, was achieved in five patients (55.6%). Overall fistula persistence (n = 1) or reopening (n = 4) occurred in five patients (55.6%) 0-15 days after stent placement. The causes of reopening were due to the gap between the stent and the esophagus (n = 3) or stent migration (n = 1). For fistula persistence or reopening, additional interventional management, such as gastrostomy, stent removal, or stent reinsertion, was performed. Stent migration occurred as a complication in one patient with EPF from a benign cause secondary to postoperative empyema. In the eight patients who died during the follow-up period, the mean and median survival times were 78.8 days and 46 days, respectively. Placement of a covered expandable metallic esophageal stent for the palliative treatment of EPF is technically feasible, although the rate of clinical success was poor secondary to fistula persistence or reopening. Fistula reopening was caused by the gap between the stent and the esophagus or by stent migration, and additional interventional treatment was useful to ensure enteral nutritional support. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

cancerous esophagotracheal fistula: treatment of placement with covered self-expanding metallic stent

International Nuclear Information System (INIS)

Han Xinwei; Li Tianxiao; Wang Ruilin; Fan Qingxia

1997-01-01

Purpose: To treat the esophagotracheal fistula that was the main cause of death in patients with esophageal carcinoma, the placement of the stent was studied. Materials and methods: Under the fluoroscopic guidance, 28 stents (5 stents made in USA and 23 in China) were successfully implanted in all the 28 patients with esophagotracheal fistula. Results: The aphagia of the patients was greatly improved and a normal diet could be swallowed at once after the placement of the stents. The 27 cases of inhalation pneumonia that caused by the fistula was recovered. Conclusion: The result indicated that the treatment with the placement of the covered self-expanding stent is simple, safe, and effective for most patients with aphagia and pneumonia due to esophagotracheal fistula

Novel biliary self-expanding metal stents: indications and applications.

Science.gov (United States)

Blero, Daniel; Huberty, Vincent; Devière, Jacques

2015-03-01

Endoscopic insertion of a self-expanding metal stent (SEMS) through a malignant common bile duct stricture is the first line of palliation for malignant jaundice. Patency of these stents remains a major concern. SEMS dysfunction can result from tumor ingrowth, overgrowth and/or clogging. Initial SEMS modifications involved covering the central part of the stent in order to reduce ingrowth and ultimately increase patency. Fully covered stents became available shortly after reports of their use in human patients. The potential removability and radial strength of SEMS have led to evaluation of their use in new indications including benign biliary strictures, post sphincterotomy bleeding and perforation. Other aspects of development include the addition of features such as anti-reflux valves, drug elution and spontaneous biodegradability. These aspects and their clinical implications are reviewed and discussed.

[The application of Y-shaped self-expandable covered metal stents in the thoracostomach-airway fistula: a single center, 11 years experience].

Science.gov (United States)

Fang, Yi; Li, Tengfei; Han, Xinwei; Wu, Gang; Ren, Jianzhuang; Ren, Kewei; Lu, Huibin; Zhang, Quanhui; Li, Zongming

2015-08-01

To investigate the clinical feasibility and efficacy of Y-shaped self-expandable covered metal stents (Y-stents) in the management of thoracostomach-airway fistula. Retrospective analysis was performed for 108 patients treated for thoracostomach-airway fistula with Y-shaped self-expandable coated metal stents between April 2003 and October 2014. Y-stents were designed based on the dimensions of trachea and bronchus and sites of the fistula and then were inserted under DSA monitoring. There were 65 cases with single big Y-stent placement, 26 cases with single small Y-stent placement, 23 cases with double Y-stents placement, and 1 case with 3 Y-stents placement. Stent implantation was successfully accomplished with single manipulation in all patients. Complete occlusion of the fistula was obtained in 104 patients after the primary manipulation, and 4 patients required a secondary manipulation where a double Y-stents was inserted because of failure of primary manipulate. Ninety-two patients completed the follow-up , while 16 were lost. Fifty-nine patients died while 33 were alive with marked improvement in their quality of life. The placement of Y-stents can effectively occlude the thoracostomach-airway fistula in patients who had had the esophageal tumors resected. The technique is not only feasible but reliable to improve the quality of life of the patients.

Endoscopic removal of laser-cut covered self-expandable metallic biliary stents: A report of six cases.

Science.gov (United States)

Tanisaka, Yuki; Ryozawa, Shomei; Kobayashi, Masanori; Harada, Maiko; Kobatake, Tsutomu; Omiya, Kumiko; Iwano, Hirotoshi; Arai, Shin; Nonaka, Kouichi; Mashimo, Yumi

2018-02-01

Covered self-expandable metallic stents (CSEMS) may provide palliative drainage for unresectable distal malignant biliary strictures. Laser-cut CSEMS allows easy positioning due to its characteristic of minimal stent shortening. Endoscopic stent removal is sometimes recommended for recurrent biliary obstruction (RBO). However, there are no previous reports of endoscopic removal of laser-cut CSEMS. The current study presents data from 6 patients who were placed a laser-cut CSEMS for unresectable distal malignant biliary strictures, and later endoscopic stent removal was attempted for RBO at the present institute. The duration of stent placement, the procedural success rate, the procedural duration, and accidental complications were evaluated. The mean duration of stent placement was 156±37.9 days (range, 117-205). The procedural success rate was 100%. The mean procedural duration was 11.8±7.5 min (range, 5-24). No complications were reported. Laser-cut CSEMS were safely removed from all patients. The present case report is the first to demonstrate that Endoscopic stent removal of laser-cut CSEMS was safely performed.

Esophagojejunal anastomotic leak managed with self expandable metallic stent

Directory of Open Access Journals (Sweden)

Arvind Madurandagam Annapillai

2013-01-01

Full Text Available Esophagealjejunal anastomotic leak after gastrectomy is a serious surgical emergency with high mortality. This report describes a 57-year-old male with esophagojejunal anastomotic leak following total gastrectomy for gastric cancer and was managed successfully with self-expandable metallic stent. To our knowledge this is the first such report from India. This case report highlights the need of interdisciplinary coordination in managing this difficult clinical situation. Endotherapy with self-expandable metallic stent (SEM provided twin benefits of improving respiratory embarrassment and the joy of eating. Therapy of such difficult cases must be individualized; however, and SEM stent usage is a viable option

Self-Expanding Metal Stenting for Palliation of Patients with Malignant Colonic Obstruction

DEFF Research Database (Denmark)

Meisner, Søren; González-Huix, Ferran; Vandervoort, Jo G

2012-01-01

Background. Self-expanding metal stents can alleviate malignant colonic obstruction in incurable patients and avoid palliative stoma surgery. Objective. Evaluate stent effectiveness and safety on palliation of patients with malignant colorectal strictures. Design. Two prospective, one Spanish....... Interventions(s). Self-expanding metal stent placement. Main Outcome Measures. Procedural success, clinical success, and safety. Results. Procedural success was 98.4% (251). Clinical success rates were 87.8% at 30 days, 89.7% at 3 months, 92.8% at 6 months, and 96% at 12 months. Overall perforation rate was 5...... for patients with malignant colonic obstruction should be self-expanding metal stent placement due to high rates of technical success and efficacy in symptom palliation and few complications....

Full covered self-expandable metal stents for the treatment of anastomotic leak using a silk thread.

Science.gov (United States)

Choi, Cheol Woong; Kang, Dae Hwan; Kim, Hyung Wook; Park, Su Bum; Kim, Su Jin; Hwang, Sun Hwi; Lee, Si Hak

2017-07-01

To evaluate the safety and effectiveness of fixation of the fully covered self-expandable metal stent (SEMS) placement using a silk thread for complete closure of an anastomotic leak. An anastomotic leak is a life-threatening complication after gastrectomy. Although the traditional treatment of choice was surgical re-intervention, an endoscopic SEMS can be used alternatively.During the study period, we retrospectively reviewed consecutive patients who received a modified covered SEMS capable of being fixed using a silk thread (Shim technique) due to an anastomotic leak after gastrectomy to prevent stent migration. Demographic data, stent placement and removal, clinical success, time to resolution, and complications were evaluated.A total of 7 patients underwent fully covered SEMS with a silk thread placement for an anastomotic leak after gastrectomy to treat gastric cancer. The patients' mean age was 71.3 ± 8.0 years. Man sex was predominant (85.7%). All patients' American Society of Anesthesiologists (ASA) scores were between I and III. Total gastrectomy was performed in 5 patients (71.4%) and proximal gastrectomy was performed in 2 patients (28.6%). The time between gastrectomy and stent insertion was 22.3 ± 11.1 days. The size of the leaks was 27.1 ± 11.1 mm. Technical success and complete leak closure were achieved in all patients. Stent migration was absent. All stents were removed between 4 and 6 weeks. Delayed esophageal stricture was found in 1 patient (14.2) and successfully resolved after endoscopic balloon dilation.For an anastomotic leak after gastrectomy, fully covered SEMS placement with a silk thread is an effective and safe treatment option without stent migration. The stent extraction time between 4 and 6 weeks was optimal without severe complications.

Renal Transplant Ureteral Stenosis: Treatment by Self-Expanding Metallic Stent

International Nuclear Information System (INIS)

Cantasdemir, Murat; Kantarci, Fatih; Numan, Furuzan; Mihmanli, Ismail; Kalender, Betul

2003-01-01

We report the use of a metallic stent in a transplant ureteral stenosis. A 28-year-old man with chronic renal failure due to chronic pyelonephritis, who received a living-donor renal transplant, presented with transplant ureteral stenosis. The stenosis was unresponsive to balloon dilation and was treated by antegrade placement of a self-expanding Memotherm stent. The stentedureter stayed patent for 3 years. It may be reasonable to treat post-transplant ureteral stenosis resistant to balloon dilation with self-expanding metallic stents. However, long-term follow-up is required to evaluate the efficacy of this treatment

Covered self-expandable metallic stent placement for a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

International Nuclear Information System (INIS)

Lee, Woon Ha; Jung, Gyoo Sik; Kim, Kyu Jong; Lee, Sang Ho; Ko, Ji Ho; Jeong, Kyung Soon

2007-01-01

To evaluate the technical feasibility and clinical effectiveness of stent placement for the treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer. Under fluoroscopic guidance, one or two covered stents were placed in 20 consecutive patients (age range, 44-75 years) with an anastomotic stricture due to a recurrent gastric malignancy. Before stent placement, all patients had severe nausea and recurrent vomiting after ingestion. Stent placement was technically successful for all patients, and no procedural complications occurred. After stent placement, 18 of 20 (90.0%) patients were able to ingest at least a liquid diet and had a markedly decreased incidence of vomiting. During the follow-up of 2-116 weeks (mean, 25.5 weeks), stent migration occurred in two patients (10.0%) on one day after the procedure. All patients with stent migration were treated successfully by means of placing a second stent. Three patients showed a recurrence of the stricture due to tumor overgrowth; two of the patients were treated with coaxial placement of a second stent. Another patient refused additional management. Covered self-expandable metallic stent placement seems to be technically feasible and effective for palliative treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

Covered self-expandable metallic stent placement for a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer

Energy Technology Data Exchange (ETDEWEB)

Lee, Woon Ha; Jung, Gyoo Sik; Kim, Kyu Jong; Lee, Sang Ho [Gospel Hospital, College of Medicine, Kosin University, Busan (Korea, Republic of); Ko, Ji Ho [Masan Samsung Medical Center, Sungkyunkwan University School of University, Masan (Korea, Republic of); Jeong, Kyung Soon [University of Ulsan Colleg of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

2007-09-15

To evaluate the technical feasibility and clinical effectiveness of stent placement for the treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer. Under fluoroscopic guidance, one or two covered stents were placed in 20 consecutive patients (age range, 44-75 years) with an anastomotic stricture due to a recurrent gastric malignancy. Before stent placement, all patients had severe nausea and recurrent vomiting after ingestion. Stent placement was technically successful for all patients, and no procedural complications occurred. After stent placement, 18 of 20 (90.0%) patients were able to ingest at least a liquid diet and had a markedly decreased incidence of vomiting. During the follow-up of 2-116 weeks (mean, 25.5 weeks), stent migration occurred in two patients (10.0%) on one day after the procedure. All patients with stent migration were treated successfully by means of placing a second stent. Three patients showed a recurrence of the stricture due to tumor overgrowth; two of the patients were treated with coaxial placement of a second stent. Another patient refused additional management. Covered self-expandable metallic stent placement seems to be technically feasible and effective for palliative treatment of a post-operative malignant anastomotic stricture secondary to recurrent gastric cancer.

Efficacy and safety of a new fully covered self-expandable non-foreshortening metal esophageal stent.

Science.gov (United States)

Dua, Kulwinder S; Latif, Sahibzada U; Yang, Juliana F; Fang, Tom C; Khan, Abdul; Oh, Young

2014-10-01

Fully covered esophageal self-expandable metal stents (SEMSs) are potentially removable but can be associated with high migration rates. For precise positioning, non-foreshortening SEMSs are preferred. Recently, a new fully covered non-foreshortening SEMS with anti-migration features was introduced. To evaluate the efficacy and safety of this new esophageal SEMS. Retrospective study. Single, tertiary-care center. Consecutive patients with malignant and benign strictures with dysphagia grade of ≥3 and patients with fistulas/leaks were studied. Stent placement and removal. Technical success in stent deployment/removal, efficacy in relieving dysphagia and sealing fistulas/leaks, and adverse events. Forty-three stents were placed in 35 patients (mean [± standard deviation] age 65 ± 11 years; 31 male), 24 for malignant and 11 for benign (5 strictures, 6 leaks) indications. Technical success in precise SEMS placement was 100%. The after-stent dysphagia grade improved significantly (at 1 week: 1.5 ± 0.7; at 4 weeks: 1.2 ± 0.4; baseline: 3.8 ± 0.4; P stents were removed for clinical indications, with technical success of 100%. All leaks sealed after SEMS placement and did not recur after stent removal. All benign strictures recurred after stent removal. Adverse events included migration (14%), chest pain (11%), and dysphagia from tissue hyperplasia (6%). There was no stent-related mortality. Nonrandomized, single-center study. The new esophageal SEMS was effective in relieving malignant dysphagia, allowed for precise placement, and was easily removable. It was effective in treating benign esophageal fistulas and leaks. Stent-related adverse events were acceptable. Copyright © 2014 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Role of Self-Expandable Metal Stents in Acute Variceal Bleeding

Directory of Open Access Journals (Sweden)

Fuad Maufa

2012-01-01

Full Text Available Acute variceal bleeding continues to be associated with significant mortality. Current standard of care combines hemodynamic stabilization, antibiotic prophylaxis, pharmacological agents, and endoscopic treatment. Rescue therapies using balloon tamponade or transjugular intrahepatic portosystemic shunt are implemented when first-line therapy fails. Rescue therapies have many limitations and are contraindicated in some cases. Placement of fully covered self-expandable metallic stent is a promising therapeutic technique that can be used to control bleeding in cases of refractory esophageal bleeding as an alternative to balloon tamponade. These stents can be left in place for as long as two weeks, allowing for improvement in liver function and institution of a more definitive treatment.

Covered versus Uncovered Self-Expandable Metal Stents for Managing Malignant Distal Biliary Obstruction: A Meta-Analysis.

Science.gov (United States)

Li, Jinjin; Li, Tong; Sun, Ping; Yu, Qihong; Wang, Kun; Chang, Weilong; Song, Zifang; Zheng, Qichang

2016-01-01

To compare the efficacy of using covered self-expandable metal stents (CSEMSs) and uncovered self-expandable metal stents (UCSEMSs) to treat objective jaundice caused by an unresectable malignant tumor. We performed a comprehensive electronic search from 1980 to May 2015. All randomized controlled trials comparing the use of CSEMSs and UCSEMSs to treat malignant distal biliary obstruction were included. The analysis included 1417 patients enrolled in 14 trials. We did not detect significant differences between the UCSEMS group and the CSEMS group in terms of cumulative stent patency (hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.19-4.53; p = 0.93, I2 = 0%), patient survival (HR 0.77, 95% CI 0.05-10.87; p = 0.85, I2 = 0%), overall stent dysfunction (relative ratio (RR) 0.85, M-H, random, 95% CI 0.57-1.25; p = 0.83, I2 = 63%), the overall complication rate (RR 1.26, M-H, fixed, 95% CI 0.94-1.68; p = 0.12, I2 = 0%) or the change in serum bilirubin (weighted mean difference (WMD) -0.13, IV fixed, 95% CI 0.56-0.3; p = 0.55, I2 = 0%). However, we did detect a significant difference in the main causes of stent dysfunction between the two groups. In particular, the CSEMS group exhibited a lower rate of tumor ingrowth (RR 0.25, M-H, random, 95% CI 0.12-0.52; p = 0.002, I2 = 40%) but a higher rate of tumor overgrowth (RR 1.76, M-H, fixed, 95% CI 1.03-3.02; p = 0.04, I2 = 0%). Patients with CSEMSs also exhibited a higher migration rate (RR 9.33, M-H, fixed, 95% CI 2.54-34.24; p = 0.008, I2 = 0%) and a higher rate of sludge formation (RR 2.47, M-H, fixed, 95% CI 1.36-4.50; p = 0.003, I2 = 0%). Our meta-analysis indicates that there is no significant difference in primary stent patency and stent dysfunction between CSEMSs and UCSEMSs during the period from primary stent insertion to primary stent dysfunction or patient death. However, when taking further management for occluded stents into consideration, CSEMSs is a better choice for patients with malignant biliary

The technique study and primary clinical application of inverted Y-shaped self-expandable metal airway stent

International Nuclear Information System (INIS)

Han Xinwei; Wu Gang; Ma Ji; Yang Ruimin; Guan Sheng; Ma Nan; Wang Yanli

2007-01-01

Objective: To investigate the feasibility and primary therapeutic effect of inverted Y-shaped self-expandable metal stent for complex airway stenosis. Methods: On the standpoint of the peculiar anatomic structure and the pathological changes of complex airway stenosis, we designed the inverted Y-shaped self-expandable metal stent. Under the fluoroscopic guidance, 7 stents were implanted in 7 cases of airway complex stenosis. Results: The inverted Y-shaped self-expandable metal stents were placed seccussfully, with instantaneous relief of dyspnea and improvement of living quality. Conclusion: The placement of inverted Y-shaped self-expandable metal stent is feasible and safe for treating airway complex stenosis. (authors)

The treatment of complex airway diseases with inverted Y-shaped self-expandable metal stent

International Nuclear Information System (INIS)

Li Jianming; Jia Guangzhi

2011-01-01

Objective: To investigate the application and therapeutic effects of inverted Y-shaped self-expandable metal airway stent in treating complex airway diseases (stenosis or fistula). Methods: According to the distinctive anatomic structure and the pathological changes of complex airway stenosis or fistula, the inverted y-shaped self-expandable metal airway stent was designed. Under fluoroscopic monitoring, a total of 12 inverted Y-shaped self-expandable metal stents were implanted in 12 patients with complex airway diseases. Results: Stent placement in the trachea-bronchial tree was technically successful in all patients. After the operation, the symptom of dyspnea was immediately relieved and the bucking following food intake disappeared. The general physical condition and living quality were much improved in all patients. Conclusion: The use of inverted Y-shaped self-expandable metal airway stent for the management of complex airway stenosis involving the tracheal carina was a simple and safe procedure and it has satisfactory short-term clinical results. (authors)

Effectiveness and Safety of Endoscopic Treatment of Benign Biliary Strictures Using a New Fully Covered Self Expandable Metal Stent

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Mihir S. Wagh

2013-01-01

Full Text Available Background. In patients with benign biliary strictures, the use of fully covered self-expandable metal stents (SEMS has been proposed as an alternative to plastic stenting, but high quality prospective data are sparse. This study was performed to evaluate the long-term effectiveness and safety of a new fully covered SEMS for benign biliary strictures. Methods. All consecutive patients with benign biliary strictures were treated with placement of a fully covered SEMS (WallFlex for 6 months. Short- and long-term stricture resolution, adverse events, and ease of stent removal were recorded. Results. 23 patients were enrolled. Stricture etiology was chronic pancreatitis (14, postorthotopic liver transplant (4, idiopathic (4, and biliary stones (1. All ERCPs were technically successful. All stents were successfully removed. Short-term stricture resolution was seen in 22/23 (96% patients. Long-term success was 15/18 (83.3%. All 3 failures were patients with biliary strictures in the setting of chronic calcific pancreatitis. Conclusions. The use of the new SEMS for the treatment of benign biliary strictures led to short-term stricture resolution in the vast majority of patients. Over a long-term followup the success rate appears favorable compared to historical results achieved with multiple plastic stenting, particularly in patients with chronic pancreatitis. The study was registered with ClinicalTrials.gov (NCT01238900.

Tracheal Penetration and Tracheoesophageal Fistula Caused by an Esophageal Self-Expanding Metallic Stent

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Karan Madan

2014-01-01

Full Text Available Tracheal penetration of esophageal self-expanding metallic stents (SEMS with/without tracheoesophageal fistula (TEF formation is a rare occurrence. We report the case of a 66-year-old female patient with advanced esophageal squamous cell carcinoma who had undergone palliative esophageal stenting on three occasions for recurrent esophageal stent obstruction. On evaluation of symptoms of breathing difficulty and aspiration following third esophageal stent placement, tracheal erosion and TEF formation due to the tracheal penetration by esophageal stent were diagnosed. The patient was successfully managed by covered tracheal SEMS placement under flexible bronchoscopy.

Assessment of safety and efficacy of an indigenous self-expandable fully covered esophageal metal stent for palliation of esophageal cancer.

Science.gov (United States)

Padhan, R K; Nongthombam, S K; Venuthurimilli, A; Dhingra, R; Sahni, P; Garg, P K

2016-01-01

Patients with unresectable esophageal cancer require palliation for dysphagia. Placement of a self-expandable metal stent (SEMS) is the procedure of choice for palliation of dysphagia. To evaluate the safety and efficacy of an indigenous fully-covered SEMS in patients with esophageal cancer. Eligible patients with unresectable esophageal cancer requiring palliation for dysphagia were included in the study. An indigenous fully covered SEMS of appropriate length was placed under endoscopic and fluoroscopic guidance. Outcome measures assessed were adverse events and improvement in dysphagia. Twenty one patients (mean age 57.71±13.14 years; 17 males) were included. After stenting, dysphagia score decreased from 3.2+0.4 to 0.35+0.74 at 4 weeks. Adverse events included retrosternal pain, respiratory distress and aspiration pneumonia in 12, 2 and 1 patients respectively. Five patients required repeat stenting due to stent migration in 4 (following radiotherapy in 3) and tumour ingrowth in 1. There was primary stent malfunction in one patient. The median survival of patients was 140 (76-199) days, which was higher in those who received radiotherapy. The stent was reasonably safe and effective to relieve dysphagia due to unresectable esophageal cancer.

Feasibility of using bulk metallic glass for self-expandable stent applications.

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Praveen Kumar, Gideon; Jafary-Zadeh, Mehdi; Tavakoli, Rouhollah; Cui, Fangsen

2017-10-01

Self-expandable stents are widely used to restore blood flow in a diseased artery segment by keeping the artery open after angioplasty. Despite the prevalent use of conventional crystalline metallic alloys, for example, nitinol, to construct self-expandable stents, new biomaterials such as bulk metallic glasses (BMGs) are being actively pursued to improve stent performance. Here, we conducted a series of analyses including finite element analysis and molecular dynamics simulations to investigate the feasibility of using a prototypical Zr-based BMG for self-expandable stent applications. We model stent crimping of several designs for different percutaneous applications. Our results indicate that BMG-based stents with diamond-shaped crowns suffer from severe localization of plastic deformation and abrupt failure during crimping. As a possible solution, we further illustrate that such abrupt failure could be avoided in BMG-based stents without diamond shape crowns. This work would open a new horizon for a quest toward exploiting superior mechanical and functional properties of metallic glasses to design future stents. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1874-1882, 2017. © 2016 Wiley Periodicals, Inc.

Early recurrence of obstructive jaundice after placement of a self-expanding metal endoprosthesis

NARCIS (Netherlands)

Fockens, P.; Waxman, I.; Davids, P. H.; Huibregtse, K.; Tytgat, G. N.

1992-01-01

Self-expanding metal endoprostheses have ben used in the treatment of malignant obstructive jaundice for a few years. We report on a patient with obstructive jaundice due to a metastasis of a squamous cell lung cancer into the pancreatic head who received an expandable metal endoprosthesis and

Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent

International Nuclear Information System (INIS)

Chen, G.; Wang, Z.; Liang, X.; Wang, Y.; Wang, Y.; Wang, Z.; Xian, J.

2013-01-01

Aim: To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Materials and methods: Twenty-one patients with cuff-related tracheal stenosis, Meyer–Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh–Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Results: Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4–12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent

Treatment of cuff-related tracheal stenosis with a fully covered retrievable expandable metallic stent.

Science.gov (United States)

Chen, G; Wang, Z; Liang, X; Wang, Y; Wang, Y; Wang, Z; Xian, J

2013-04-01

To investigate the clinical effectiveness, complications, and optimal duration of use of covered retrievable expandable metallic stents in the management of cuff-related tracheal stenosis. Twenty-one patients with cuff-related tracheal stenosis, Meyer-Cotton grade II (29%) and III (71%), who underwent fluoroscopically guided placement of covered retrievable expandable metallic stents were studied. Sixty-four-section computed tomography (CT) and bronchovideoscopy were performed prior to stent insertion, 1 month after stent insertion, in the case of stent-related complications, and after stent removal. Clinical manifestations, Hugh-Jones classification, and forced expiratory volume in 1 s (FEV1) were used to evaluate respiratory function before and after stent insertion and removal. The diameter of the stricture and FEV1 changes before insertion and after removal were analysed using the paired samples t-test. A p-value of ≤0.05 was considered statistically significant. Twenty-one patients had 27 covered retrievable expandable metallic stents placed. Stents were electively removed from 20 patients. The median duration of stent placement was 5 months (range 4-12 months). One stent was not removed due to mucopolysaccharidosis type II (MPS II or Hunter syndrome) with tracheomalacia. After stent removal, airway dimensions increased and airway occlusion was symptomatically relieved in all patients. CT and bronchovideoscopy showed patent lumens with increased dimensions. Stent-related complications occurred in 19 (91%) patients, including granulation tissue formation (n = 18, 86%), stent migration and stent expectoration (n = 2, 10%), mucus plugging (n = 1, 5%), and halitosis (n = 6, 29%). Some patients experienced multiple complications, which were all managed effectively while the stent was still in place. There was a statistically significant difference in the diameter of the stricture and FEV1 between the time of stent insertion and removal. An improvement in

Palliation of malignant gastric obstruction : fluoroscopic guided covered metallic stent placement

International Nuclear Information System (INIS)

Lee, Jeong Min; Han, Young Min; Kim, Chong Soo; Lee, Sang Yong; Choi, Ki Chul; Lee, Soo Tak; Han, Hyun Young

2000-01-01

To demonstrate the feasibility and clinical efficacy of self-expanding, covered metallic stent placement for the palliative treatment of malignant gastric obstruction. Under fluoroscopic guidance, the placement of self-expanding, covered stents was attempted in 23 patients (age range, 31-78 years) with inoperable or recurrent gastric malignancies. All 23 suffered dysphagia and/or vomiting after the ingestion of soft foods, or swallowing difficulty. Three different types of self-expanding, covered metallic stents were used and in all patients, these were placed perorally using over the guide wire technique. Success was defined both technically and clinically. Stent placement was technically successful in 19 patients (82.6%) but because the guidewire failed to successfully negotiate the sites at which there was obstruction, was unsuccessful in four (17.4%). Stent placement was well tolerated in all patients except one, in whom an acutely angled efferent loop from remnant stomach was present. In this case, stent placement required a strong metallic guidewire. After placement, 17 of the 19 patients (89.5%) were able to ingest solid and/or soft foods without dysphagia and showed a markedly decreased incidence of vomiting. Two others showed some improvement in the frequency of vomiting but were able to ingest only a liquid diet. In one patient, the stent migrated two days after the procedure. During the follow-up period of 2-7 months (mean, 74 days), there were no clinically significant complications. For the short-term palliative treatment of patients with gastric inlet or outlet obstruction, the placement of self-expanding metallic stents has proven relatively easy and safe, as well as reasonably effective. (author)

Self-Expandable Metal Stents and Trans-stent Light Delivery: Are Metal Stents and Photodynamic Therapy Compatible?

Science.gov (United States)

Wang, Luo-Wei; Li, Li-Bo; Li, Zhao-Shen; Chen, Yang K; Hetzel, Fred W.; Huang, Zheng

2008-01-01

Background and Objectives: Obstructive non-small cell lung cancer and obstructive esophageal cancer are US FDA approved indications of photodynamic therapy (PDT). The usefulness of PDT for the treatment of cholangiocarcinoma is currently under clinical investigation. Endoscopic stenting for lumen restoration is a common palliative intervention for those indications. It is important to assess whether self-expandable metal stents are compatible with trans-stent PDT light delivery. Study Design/Materials and Methods: Direct effects of various components of metal biliary (n = 2), esophageal (n = 2), and bronchial (n = 1) stents on PDT light transmittance and distribution were examined using a point or linear light source (630 or 652 nm diode laser). Resected pig biliary duct and esophageal wall tissues were used to examine the feasibility of PDT light delivery through the fully expanded metal stents. Results: While using a point light source, the metal components (thread and joint) of the stent could cause a significant shadow effect. The liner material (polytetrafluoroethylene or polyurethane) could cause various degrees of light absorption. When the stent was covered with a thin layer of biliary duct and esophageal tissues containing all wall layers, the shadow effect could be mitigated due to tissue scattering. Conclusions: This study clearly demonstrates that it is feasible to combine stenting and PDT for the treatment of luminal lesions. PDT light dose should be adjusted to counteract the reduction of light transmittance caused by the metal and liner materials of stent. PMID:18951422

Safety and Efficacy of a Fully Covered Self-Expandable Metallic Stent in Benign Airway Stenosis.

Science.gov (United States)

Fortin, Marc; Lacasse, Yves; Elharrar, Xavier; Tazi-Mezalek, Rachid; Laroumagne, Sophie; Guinde, Julien; Astoul, Philippe; Dutau, Hervé

2017-01-01

The use of self-expandable metallic stents (SEMS) in benign airway disease was the object of a boxed warning from the United States Food and Drug Administration in 2005 due to the risk of stent-related complications and difficulties associated with their removal. Third-generation fully covered SEMS have been commercialized since this warning and theoretically should not present the same difficulties associated with removal as they cannot become embedded in the airway mucosa. We aimed to examine the safety and efficacy of a specific third-generation SEMS, the Silmet stent. We reviewed the records of all patients treated for benign airway stenosis with third-generation Silmet SEMS from January 2011 to December 2015 at the North Hospital of Marseilles, France. Forty SEMS were inserted in 30 patients over this period. Twenty (50.0%) stents were removed because of stent-related complications after a median of 77.0 ± 96.6 days (migration 32.5%, granulation tissue formation 7.5%, subjective intolerance 5.0%, mucus plugging 2.5%, laryngeal edema 2.5%). There were no cases of stent-related mortality. All complications were managed successfully endoscopically. Thirty-six stents (90.0%) were removed successfully after a median of 122.0 ± 113.2 days without any complications. The clinical success rate of stent treatment was 40.7%. Third-generation SEMS are a safe treatment option for complex benign airway stenosis, but complications requiring stent removal are frequent. Further studies are needed to compare the performance of third-generation SEMS and silicone stents in benign airway stenosis. © 2017 S. Karger AG, Basel.

Self-Expanding Metal Stents Improve Swallowing and Maintain Nutrition During Neoadjuvant Therapy for Esophageal Cancer.

Science.gov (United States)

Smith, Zachary L; Gonzaga, Jason E; Haasler, George B; Gore, Elizabeth M; Dua, Kulwinder S

2017-06-01

Patients with locally advanced esophageal cancer can have significant dysphagia. Nutritional support during neoadjuvant therapy is often delivered via nasoenteric or percutaneous feeding tubes. These approaches do not allow for per-oral feeding. Evaluate the safety and efficacy of fully covered self-expanding metal esophageal stents for nutritional support during neoadjuvant therapy. This was a pilot, prospective study at a single tertiary center. From March 2012 to May 2013, consecutive patients with esophageal cancer eligible for neoadjuvant therapy were enrolled. Metal stents were placed prior to starting neoadjuvant therapy. Data were collected at baseline and predetermined intervals until an endpoint (surgery or disease progression). Outcomes included dysphagia grade, satisfaction of swallowing score, nutritional status (weight, serum albumin), impact on surgery, and adverse events. Fourteen stents were placed in 12 patients (59.1 ± 9.5 years, 11 men, 1 woman). Dysphagia grade (pre 3.4 ± 0.5 vs post 0.2 ± 0.4, p esophageal cancer, self-expanding metal stents are safe and effective in relieving dysphagia and maintaining nutrition. They allow patients to eat orally, thereby improving patient satisfaction. The presence of an in situ stent did not interfere with surgery.

Predictors of outcomes in patients undergoing covered and uncovered self-expandable metal stent placement for malignant gastric outlet obstruction: a multicenter study.

Science.gov (United States)

Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Ban, Tesshin; Natsume, Makoto; Okumura, Fumihiro; Nakazawa, Takahiro; Takada, Hiroki; Hirano, Atsuyuki; Jinno, Naruomi; Togawa, Shozo; Ando, Tomoaki; Kataoka, Hiromi; Joh, Takashi

2017-02-01

Uncovered self-expandable metal stents (U-SEMSs) and covered self-expandable metal stents (C-SEMSs) are available for palliative therapy for malignant gastric outlet obstruction (GOO). However, clinical differences and indications between the 2 types of SEMSs have not been elucidated. We retrospectively compared 126 patients with U-SEMS and 126 patients with C-SEMSs with regard to clinical outcome and factors predictive of clinical improvement after SEMSs placement. No significant difference was observed between the U-SEMS and C-SEMS groups with respect to technical success, clinical success, GOO score, or time to stent dysfunction. Stent migration was significantly more frequent in patients with C-SEMSs (U-SEMSs, .79%; C-SEMSs, 8.73%; P = .005). Karnofsky performance status, chemotherapy, peritoneal dissemination, and stent expansion ≤ 30% were associated significantly with poor GOO score improvement in multivariable analyses, but stent type was not (P = .213). In subgroup analyses, insufficient (≤30%) stent expansion was an independent factor in patients with U-SEMSs (P = .041) but not C-SEMSs. In the insufficient stent expansion subgroup, C-SEMSs was associated significantly with superior clinical improvement compared with U-SEMSs (P = .01). Insufficient stent expansion was observed more frequently in patients with GI obstruction because of anastomotic sites or metastatic cancer (44.8% [13/29], P = .001). No clinical difference, apart from stent migration, was observed between patients with U-SEMSs and C-SEMSs. GI obstruction because of an anastomotic site or metastatic cancer may be an indication for C-SEMS use to improve oral intake after SEMSs placement. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Percutaneous metallic self-expandable endoprostheses in malignant hilar biliary obstruction

NARCIS (Netherlands)

Stoker, J.; Laméris, J. S.; van Blankenstein, M.

1993-01-01

Forty-five patients with malignant hilar obstruction were treated with a total of 68 percutaneously inserted metallic self-expandable endoprostheses (Wallstents) for palliative biliary drainage. The stent diameter was 1 cm; the length was 3.5 to 10.5 cm. Early complications occurred in seven

Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

Directory of Open Access Journals (Sweden)

Gianfranco Donatelli

2016-05-01

Full Text Available Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist.

Preoperative biliary drainage using a fully covered self-expandable metallic stent for pancreatic head cancer: A prospective feasibility study.

Science.gov (United States)

Togawa, Osamu; Isayama, Hiroyuki; Kawakami, Hiroshi; Nakai, Yousuke; Mohri, Dai; Hamada, Tsuyoshi; Kogure, Hirofumi; Kawakubo, Kazumichi; Sakamoto, Naoya; Koike, Kazuhiko; Kita, Hiroto

2018-01-01

The role of endoscopic preoperative biliary drainage (PBD) for pancreatic head cancer is controversial because of the high incidence of stent occlusion before surgery. This study was performed to evaluate the feasibility and safety of PBD using a fully covered self-expandable metallic stent (FCSEMS). This multicenter prospective study involved 26 patients treated for pancreatic head cancer with distal bile duct obstruction from April 2011 to March 2013. An FCSEMS was endoscopically placed in 24 patients. Among these, 7 patients were diagnosed with unresectable cancer, and 17 underwent surgery at a median of 18 days after FCSEMS placement. The main outcome measure was preoperative and postoperative adverse events. Two adverse events (cholecystitis and insufficient resolution of jaundice) occurred between FCSEMS placement and surgery (12%). Postoperative adverse events occurred in eight patients (47%). The cumulative incidence of stent-related adverse events 4 and 8 weeks after FCSEMS placement among the 24 patients who underwent this procedure were 19%. PBD using an FCSEMS is feasible in patients with resectable pancreatic head cancer. Placement of an FCSEMS can be an alternative PBD technique when surgery without delay is impossible. A larger randomized controlled trial is warranted.

Safety and efficacy of self-expandable metal stents for obstructive proximal and distal large bowel cancer.

Science.gov (United States)

Mitra, V; Hu, M; Majumdar, D; Krishnan, V; Chaudhury, B; Hancock, J; Dwarakanath, D

2017-03-01

Self-expandable metal stents are often used to treat obstructive large bowel cancers. This study assessed the safety and efficacy of colonic stent insertion carried out in a district general hospital. Methods A retrospective review was carried out between 1 January 2007 and 28 February 2014 to identify patients who underwent stent insertion for malignant colorectal obstruction. Results Seventy-five patients (median age 75.2 years, 70.6% male) with primary colorectal cancer underwent stent insertion - 53 underwent semi-elective self-expanded metal stent insertion (for subacute bowel obstruction) and 22 had emergency stent inserted (for acute bowel obstruction). The majority (88%) had self-expanded metal stents inserted for palliation. Technical and clinical success rates were 98.7% and 91.2%, respectively. One patient had stent-related perforation; there was no procedure-related mortality. Conclusion This study shows that self-expanded metal stent insertion in malignant colorectal obstruction is safe and effective and can be successfully delivered in a district general hospital with high technical and clinical success rates.

Polyurethane-Covered Self-expandable Nitinol Stent for Malignant Biliary Obstruction: Preliminary Results

International Nuclear Information System (INIS)

Han, Young-Min; Hwang, Seung-Bae; Lee, Soo-Teik; Lee, Jeong-Min; Chung, Gyung-Ho

2002-01-01

Purpose: To evaluate the immediate and long-term results in ten patients with malignant biliary obstruction using a polyurethane-covered, self-expandable nitinol stent.Methods: A nitinol stent, fully covered with high-elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 60-80 mm, was placed transhepatically under fluoroscopic guidance in ten patients. The length of the biliary obstruction varied between 30-50 mm. The follow-up examination included a clinical assessment, serum bilirubin measurement, and ultrasound examinations at one-month intervals in all patients. Results: Initial stent deployment was successful in eight patients. Two patients experienced proximal migration,which was solved by insertion of two, uncovered Wallstents. One patient had the stent removed after two weeks because of severe nausea and vomiting. One patient had delayed migration of the covered stent after 40 weeks. The follow-up duration was 3-40 weeks (Mean: 16.9 weeks). Seven patients died(3-26 weeks) and three patients survived (24-40 weeks). The bilirubin measurements in all patients had significantly decreased one week after stent insertion. The levels of amylase and lipase had did not increase after stent insertion. Conclusions: Apolyurethane-covered, self-expandable nitinol stent can be used effectively and safely in the treatment of malignant biliary obstruction. The preliminary results are favorable, but there is a need for further large studies to determine both long-term survival and patency

Self-expandable metal stents in the treatment of benign anastomotic stricture after rectal resection for cancer.

Science.gov (United States)

Lamazza, A; Fiori, E; Sterpetti, A V; Schillaci, A; Scoglio, D; Lezoche, E

2014-04-01

To evaluate the use of self-expandable metallic stents to treat patients with symptomatic benign anastomotic stricture after colorectal resection. Ten patients with a benign symptomatic anastomotic stricture after colorectal resection were treated with endoscopic placement of a self-expandable metal stent. The stent was placed successfully in all 10 patients without any major morbidity. At a mean follow-up of 18 months the stenosis was resolved successfully in 7 out 10 patients (70%). The remaining three patients were subsequently treated successfully with balloon dilatation. Self-expandable metal stents represent a valid alternative to balloon dilatation to treat patients with benign symptomatic anastomotic stricture after colorectal resection for cancer. Colorectal Disease © 2013 The Association of Coloproctology of Great Britain and Ireland.

Predictors of stent dysfunction after self-expandable metal stent placement for malignant gastric outlet obstruction: tumor ingrowth in uncovered stents and migration of covered stents.

Science.gov (United States)

Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Ban, Tesshin; Natsume, Makoto; Okumura, Fumihiro; Nakazawa, Takahiro; Takada, Hiroki; Hirano, Atsuyuki; Jinno, Naruomi; Togawa, Shozo; Ando, Tomoaki; Kataoka, Hiromi; Joh, Takashi

2017-10-01

Endoscopic metallic stenting is widely accepted as a palliation therapy for malignant gastric outlet obstruction (GOO). However, the predictors of stent dysfunction have not been clarified. We aimed to evaluate the predictors, especially tumor ingrowth in uncovered self-expandable metallic stents (U-SEMS) and migration of covered self-expandable metallic stents (C-SEMS), which are the main causes related to the stent characteristics. In this multicenter retrospective study, we compared patients with U-SEMS and C-SEMS in terms of clinical outcomes, and predictors of stent dysfunction. In total, 252 patients (126 with U-SEMS and 126 with C-SEMS) were enrolled. There were no significant differences in technical success, clinical success, GOO score, or time to stent dysfunction. Tumor ingrowth was significantly more frequent in U-SEMS (U-SEMS, 11.90% vs. C-SEMS, 0.79%; p = 0.002), and stent migration was significantly more frequent for C-SEMS (C-SEMS, 8.73% vs. U-SEMS, 0.79%; p = 0.005). Karnofsky performance status (p = 0.04), no presence of ascites (p = 0.02), and insufficient (stent expansion (p = 0.003) were significantly associated with tumor ingrowth in U-SEMS. Meanwhile, a shorter stent length (p = 0.05) and chemotherapy (p = 0.03) were predictors of C-SEMS migration. Both U-SEMS and C-SEMS are effective with comparable patencies. Tumor ingrowth and stent migration are the main causes of stent dysfunction for U-SEMS and C-SEMS, respectively. With regard to stent dysfunction, U-SEMS might be a good option for patients receiving chemotherapy, while C-SEMS with longer stents for patients in good condition. (Clinical trial registration number: UMIN000024059).

Self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent for the palliative treatment of malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Yoo, Oong; Jung, Gyoo Sik; Han, Byung Hoon; Shin, Dong Hoon [Gospel Hospital, College of Medicine, Kosin University, Busan (Korea, Republic of); Ko, Ji Ho [Masan Samsung Medical Center, Sungkyunkwan University School of Medicine, Masan (Korea, Republic of)

2008-06-15

We wanted to determine the technical and clinical efficacy of placing a self-expandable PTFE-covered nitinol stent for the management of inoperable malignant biliary obstruction. Thirty six patients with inoperable malignant biliary obstructions were treated by placement of self-expandable PTFE-covered nitinol stents (S and G Biotech Corporation, Seongnam, Korea). Clinical evaluation was done with assessment of the serum bilirubin and alkaline phosphatase levels, which were measured before and after stent placement within 1 week, at 1 month and at 3 months. The patient survival rate and stent patency rate were calculated with performing Kaplan-Meier survival analysis. Successful stent placement was achieved in all the patients without procedure-related complication. Pancreatitis as an early complication occurred in two cases. The serum bilirubin and alkaline phosphatase levels were significantly decreased after the procedure. During the follow-up, recurrent obstructive jaundice occurred in six cases; stent migration occurred in four cases and tumor overgrowth occurred in two cases. The survival rates were 97%, 80%, 67% and 59% at 1, 3, 6 and 9 months, respectively. The stent patency rates were 96%, 92%, 86% and 86% at 1, 3, 6 and 9 months, respectively. Self-expandable PTFE-covered nitinol stent placement seems to be technically feasible and effective for the palliative treatment of malignant biliary obstruction.

Self-expandable polytetrafluoroethylene (PTFE)-covered nitinol stent for the palliative treatment of malignant biliary obstruction

International Nuclear Information System (INIS)

Yoo, Oong; Jung, Gyoo Sik; Han, Byung Hoon; Shin, Dong Hoon; Ko, Ji Ho

2008-01-01

We wanted to determine the technical and clinical efficacy of placing a self-expandable PTFE-covered nitinol stent for the management of inoperable malignant biliary obstruction. Thirty six patients with inoperable malignant biliary obstructions were treated by placement of self-expandable PTFE-covered nitinol stents (S and G Biotech Corporation, Seongnam, Korea). Clinical evaluation was done with assessment of the serum bilirubin and alkaline phosphatase levels, which were measured before and after stent placement within 1 week, at 1 month and at 3 months. The patient survival rate and stent patency rate were calculated with performing Kaplan-Meier survival analysis. Successful stent placement was achieved in all the patients without procedure-related complication. Pancreatitis as an early complication occurred in two cases. The serum bilirubin and alkaline phosphatase levels were significantly decreased after the procedure. During the follow-up, recurrent obstructive jaundice occurred in six cases; stent migration occurred in four cases and tumor overgrowth occurred in two cases. The survival rates were 97%, 80%, 67% and 59% at 1, 3, 6 and 9 months, respectively. The stent patency rates were 96%, 92%, 86% and 86% at 1, 3, 6 and 9 months, respectively. Self-expandable PTFE-covered nitinol stent placement seems to be technically feasible and effective for the palliative treatment of malignant biliary obstruction

Temporary placement of covered self-expandable metallic stents in the management of benign biliary strictures.

Science.gov (United States)

Yasuda, Ichiro; Mukai, Tsuyoshi; Doi, Shinpei; Tomita, Eiichi; Moriwaki, Hisataka

2012-05-01

Currently, endoscopic intervention is widely attempted as the first-line treatment of benign biliary strictures because of its convenience and low morbidity. Plastic tube stents (PS) are usually used for such treatment; however, covered self-expandable metallic stents (C-SEMS) are becoming more commonly used at some institutions. The temporary placement of C-SEMS may lead to better outcomes because of their larger diameter and, therefore, better dilation of the stricture, especially in refractory cases. The aim of the present study was to evaluate the efficacy of the temporary placement of C-SEMS in the management of benign biliary strictures. We retrospectively reviewed our endoscopic retrograde cholangiopancreatography (ERCP) database (May 1996 to December 2010), and extracted the data of patients who underwent endoscopic treatment for benign biliary strictures. Then, the follow-up data from patient charts were reviewed to determine the long-term outcomes of those procedures. All patients (n = 56) initially had a PS placed, with or without balloon dilation. However, C-SEMS placement was later attempted in 12 patients because the stricture was refractory to placement of the PS. During their follow-up periods, two patients died of unrelated diseases after 15 and 17 months, and another two still had the C-SEMS in place after 9 and 50 months. In the remaining eight patients, the C-SEMS was removed after a median placement period of 6 months (range, 2-15). Seven patients in this group have not experienced a recurrence at a median follow-up time of 48 months. However, in one patient, stenosis did recur 8 months after the C-SEMS was removed. Temporary placement of C-SEMS can be a treatment option for benign biliary strictures, especially in refractory cases. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Comparison on the Efficacy between Partially Covered Self-Expandable Metal Stent with Funnel-Shaped Enlarged Head versus Uncovered Self-Expandable Metal Stent for Palliation of Gastric Outlet Obstruction

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Jung Wan Choe

2018-01-01

Full Text Available Background. Shape modification has been one of the methods adopted to improve stent patency but has not always translated into positive outcome. The aim of this study was to compare the efficacy of shape-modified partially covered self-expandable metal stent (SEMS that has enlarged head versus uncovered SEMS for palliation of gastric outlet obstruction (GOO. Methods. A total of 48 patients underwent insertion of either enlarged-head SEMS (n=24 or uncovered SEMS (uSEMS (n=24 for palliation of GOO from July 2009 to July 2016. Patients with inoperable or advanced malignancy were included. Technical feasibility and clinical outcomes were compared. Results. Technical success rate was 100% (24/24 and 95.8% (23/24 for enlarged-head SEMS group and uSEMS group, respectively. Clinical success rate was 87.5% (21/24 and 87.0% (20/23 for enlarged-head SEMS group and uSEMS group, respectively. The gastric outlet obstruction scoring system score significantly improved in both groups (p<0.001 for both. Mean survival was similar between the groups: enlarged-head SEMS group, 99.3 days (range, 19–358 days versus uSEMS group, 82.1 days (range, 11–231 days (p=0.418. The mean stent patency also showed no difference between the groups: enlarged-head SEMS group, 87.1 days (range, 8–358 days versus uSEMS group, 60.4 days (range, 2–231 days (p=0.204. With enlarged-head SEMS, distal migration did not occur, but proximal migration was observed in four cases. Conclusions. Distal migration was prevented by shaping the SEMS to have an enlarged head, but improvement in stent patency could not be observed.

Role of fluoroscopic guided self expandable metallic stents in the management of malignant esophageal strictures

OpenAIRE

Mohamed Shaker; Ahmed Deif; Amr Abdelaal

2016-01-01

Objectives: To evaluate the role of fluoroscopic guided self expanding metallic stents in the management of dysphagia caused by malignant esophageal strictures. Materials and methods: During the period between April 2010 and October 2012, 31 patients with malignant esophageal strictures were subjected to fluoroscopic guided self expanding metallic stent application. The study included 22 males and 9 females ranging in age between 22 and 75 years old with mean age of 56.8 years. Lesions wer...

Covered self-expandable metal stents in pancreatic malignancy regardless of resectability: a new concept validated by a decision analysis.

Science.gov (United States)

Kahaleh, M; Brock, A; Conaway, M R; Shami, V M; Dumonceau, J M; Northup, P G; Tokar, J; Rich, T A; Adams, R B; Yeaton, P

2007-04-01

The current treatment model for the management of malignant biliary obstruction is to place a plastic stent for unstaged pancreatic cancer. In patients with unresectable disease but a life expectancy of more than 6 months, self-expandable metal stents (SEMS) are favored because of their more prolonged patency. We analyzed the efficacy and cost-effectiveness of covered SEMS (CSEMS) in patients with pancreatic cancer and distal biliary obstruction without regard to surgical resectability. Between March 2001 and March 2005, 101 consecutive patients with obstructive jaundice secondary to pancreatic cancer underwent placement of a CSEMS. Patients with resectable tumor were offered pancreaticoduodenectomy. A model was developed to compare the costs of CSEMS and polyethylene and DoubleLayer stents. A total of 21 patients underwent staging laparoscopy, of whom 16 had a resection (76%). The 85 patients who did not have a resection had a mean survival of 5.9 months (range 1-25 months) and a mean CSEMS patency duration of 5.5 months (range 1-16 months). Life-table analysis demonstrated CSEMS patency rates of 97% at 3 months, 85% at 6 months, and 68% at 12 months. In a cost model that accounted for polyethylene and DoubleLayer stent malfunction and surgical resections, initial CSEMS placement (3177 euros per patient) was a less costly intervention than either DoubleLayer stent placement (3224 euros per patient) or polyethylene stent placement with revision (3570 euros per patient). Covered SEMS are an effective treatment for distal biliary obstructions caused by pancreatic carcinoma. Their prolonged patency and removability makes them an attractive option for biliary decompression, regardless of resectability. The strategy of initial covered SEMS placement might be the most cost-effective strategy in these patients.

Clinical feasibility of a new through-the-scope fully covered esophageal self-expandable metallic stent: an in vivo animal study.

Science.gov (United States)

Cheon, Young Koog; Lee, Tae Yoon; Sung, In Kyung; Shim, Chan Sup

2014-01-01

Most delivery devices used for esophageal stents for obstructing esophageal cancer have a diameter of 5-8 mm, a size that is too large to pass through the endoscopic working channel. The conventional esophageal stent requires multiple endoscopic procedures for implantation. The purpose of the present study was to evaluate the clinical feasibility of a newly developed fully covered, self-expanding, through-the-scope (TTS) esophageal stent in a porcine model. Eight mini pigs were used. Each animal underwent placement of a fully covered TTS stent (Hanarostent® Esophagus TTS) and the upper part of the stent was fixed by suturing with nylon. Fluoroscopy was carried out every week to assess migration of the stent. Follow-up endoscopy was done every month for 3 months to evaluate the status of the membrane, stent mesh, grade of tissue hyperplasia, and mucosal changes at both ends of the stent. All stents were successfully and easily deployed, and were placed without any distortion in the stent or without rupture of the membrane. In two cases, stent migration was observed after 8 weeks. No case of membrane disruption, stent mesh disruption or tissue hyperplasia at either end of the stent was found at the completion of the study. Our findings indicate that the new fully covered self-expanding TTS esophageal stent is easy and simple to implant, and no significant distortion of mesh or disruption of membrane was observed. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

The use of self expandable metallic stent in the management of malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Han, Joon Koo; Choi, Byung Ihn; Chung, Jin Wook; Park, Jae Hyung; Han, Gi Seok; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1993-05-15

Self expandable metallic stent is a good alternative of percutaneous transhepatic biliary drainage because it can eliminate numerous problems caused by external drainage catheter, such as tube dislodgement, bile leakage and psychotic problems. Authors analyzed initial results of self expandable metallic stents used in the patient with malignant biliary obstruction to evaluate the efficacy of the procedure and to find the technical problems in the procedure. Self expandable metallic stents were inserted in 14 patients: three with recurrent stomach cancer: three with gallbladder cancer: seven with Klaskin tumor: one with common duct cancer. Gianturco type stent was used in 9 cases ans Wallstent was used in 2 cases. In remaining three case, both Z-stent and Wallstent were used in the same patient. The average period of follow up was 104 days (4-409 days). In 13 cases, the patency of the bile duct was restored by the stent (technical success: 92.9%). Occlusions of the stent were found in two cases, after two and 13 months, respectively. Causes of failure and stent occlusion were associated duodenal obstruction, tumor overgrowth and shortening of Wallstent. In remaining 11 patients, one patient was lost to follow up an 10 patients did not show recurrent jaundice until death or last follow up. There was no major complication related to the procedure. The insertion of self expandable metallic stent is a safe procedure and can eliminate major disadvantages of PTBD. Overstenting, overlapping and evaluation of associated GI tract obstruction is crucial for obtaining technical success and long-term patency.

The use of self expandable metallic stent in the management of malignant biliary obstruction

International Nuclear Information System (INIS)

Han, Joon Koo; Choi, Byung Ihn; Chung, Jin Wook; Park, Jae Hyung; Han, Gi Seok; Han, Man Chung

1993-01-01

Self expandable metallic stent is a good alternative of percutaneous transhepatic biliary drainage because it can eliminate numerous problems caused by external drainage catheter, such as tube dislodgement, bile leakage and psychotic problems. Authors analyzed initial results of self expandable metallic stents used in the patient with malignant biliary obstruction to evaluate the efficacy of the procedure and to find the technical problems in the procedure. Self expandable metallic stents were inserted in 14 patients: three with recurrent stomach cancer: three with gallbladder cancer: seven with Klaskin tumor: one with common duct cancer. Gianturco type stent was used in 9 cases ans Wallstent was used in 2 cases. In remaining three case, both Z-stent and Wallstent were used in the same patient. The average period of follow up was 104 days (4-409 days). In 13 cases, the patency of the bile duct was restored by the stent (technical success: 92.9%). Occlusions of the stent were found in two cases, after two and 13 months, respectively. Causes of failure and stent occlusion were associated duodenal obstruction, tumor overgrowth and shortening of Wallstent. In remaining 11 patients, one patient was lost to follow up an 10 patients did not show recurrent jaundice until death or last follow up. There was no major complication related to the procedure. The insertion of self expandable metallic stent is a safe procedure and can eliminate major disadvantages of PTBD. Overstenting, overlapping and evaluation of associated GI tract obstruction is crucial for obtaining technical success and long-term patency

Unique usage of a partially covered metal stent for drainage of a pancreatic pseudocyst via endosonography-guided transcystgastrostomy.

Science.gov (United States)

Nici, Anthony J; Hussain, Syed A; Kim, Sang H; Mehta, Preeti

2012-05-01

Pancreatic pseudocysts are frequent complications of pancreatitis episodes. The current therapeutic modalities for drainage of pancreatic pseudocysts include surgical, percutaneous, and endoscopic drainage modalities. Endosonography-assisted endoscopic drainage of these pseudocysts with the placement of multiple plastic or fully covered self-expanding biliary metal stents is becoming more commonly carried out. The present case report discusses the unique and successful drainage of a pancreatic pseudocyst with the placement of a partially covered self-expanding metal stent. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Endoscopic removal of malfunctioning biliary self-expandable metallic stents.

Science.gov (United States)

Familiari, Pietro; Bulajic, Milutin; Mutignani, Massimiliano; Lee, Linda S; Spera, Gianluca; Spada, Cristiano; Tringali, Andrea; Costamagna, Guido

2005-12-01

Endoscopic removal of malfunctioning self-expandable metallic biliary stents (SEMS) is difficult and not well described. The aim of this study is to review the indications, the techniques, and the results of SEMS removal in a cohort of patients with malfunctioning stents. All patients who underwent an attempt at endoscopic removal of biliary SEMS over a 5-year period were retrospectively identified. The main indications for SEMS removal were the following: distal migration of the stent or impaction to the duodenum, impaction into the bile-duct wall, tissue ingrowth, and inappropriate length of the stent causing occlusion of intrahepatic ducts. SEMS were removed by using foreign-body forceps or polypectomy snares. Endoscopic removal of 39 SEMS (13 uncovered and 26 covered) was attempted in 29 patients (17 men; mean age, 66 years). SEMS extraction was attempted after a mean of 7.5 months (8.75 months standard deviation) post-SEMS insertion. Removal was successful in 20 patients (68.9%) and in 29 SEMS (74.3%). Covered SEMS were effectively removed more frequently than uncovered ones: 24 of 26 (92.3%) and 5 of 13 (38.4%), respectively (p < 0.05). No major complications were recorded. Multivariate analysis showed that the time interval between insertion and removal, SEMS length, stent-mesh design (zigzag vs. interlaced), and indication for removal were not predictive of success at stent removal. Endoscopic removal of biliary SEMS is feasible and safe in more than 70% of cases. Because only 38% of uncovered SEMS were removable, the presence of a stent covering is the only factor predictive of successful stent extraction. The presence of diffuse and severe ingrowth was the main feature limiting SEMS removal.

Trial of self-expandable metallic stents in the palliation of tracheo ...

African Journals Online (AJOL)

Trial of self-expandable metallic stents in the palliation of tracheo-oesophageal fistula in carcinoma of the oesophagus. ... Over half of the patients in the TOF group had concomitant pneumonia at presentation with decreased survival (p = 0.010) and a hazard ratio of 10.86. Two patients died, on days 4 and 7 respectively.

Square Stent: A New Self-Expandable Endoluminal Device and Its Applications

International Nuclear Information System (INIS)

Pavcnik, Dusan; Uchida, Barry; Timmermans, Hans; Keller, Frederick S.; Roesch, Josef

2001-01-01

The square stent is a new, simply constructed, self-expanding device that has recently been described. Compared with other stents, the square stent has a minimal amount of metal and thus requires a smaller-diameter catheter for introduction. Despite the small amount of metal present, the square stent has adequate expansile force. We have been evaluating the square stent for various interventional applications. In addition to the basic square stent, combinations of square stents and coverings for square stents were developed and evaluated to expand its uses and indications. One of the coverings tested is a new biomaterial: small intestinal submucosa (SIS). This paper will discuss the various applications of the square stent, which include a retrievable inferior vena cava filter, vascular occluder, graft adapter, and venous and aortic valves. In addition, we will review the important properties of SIS as a covering for the square stent

Self-expanding metal stents in benign biliary strictures due to chronic pancreatitis

NARCIS (Netherlands)

van Berkel, A. M.; Cahen, D. L.; van Westerloo, D. J.; Rauws, E. A.; Huibregtse, K.; Bruno, M. J.

2004-01-01

Background and Study Aims: In selected patients with chronic pancreatitis in whom conventional plastic stenting fails and in whom surgery is contraindicated or declined, insertion of a biliary self-expanding metal stent (SEMS) may be a valuable treatment option. Patients and Methods: Between 1994

Treatment of tracheobronchial stenosis with a self-expandable metallic stents

Energy Technology Data Exchange (ETDEWEB)

Kim, Yong Soo; Jeon, Seok Chol; Choi, Chul Seung; Choi, Yo Won; Hahm, Chang Kok [College of Medicine, Hanyang University, Seoul (Korea, Republic of)

1994-07-15

We analysed the role of modified Gianturco self-expandable stents in the treatment of tracheobronchial stenosis in 13 patients. We inserted modified Gianturco self-expandable stents under the fluoroscopic and bronchoscopic guidance. There were stenosis in the trachea(n=2), the right main bronchus(n=2), and the left main bronchus(n=9). The causes of the stenosis were endobronchial tuberculosis(n=10), intubation granuloma(n=1), restenosis after surgical reconstruction(n=2). Dyspnea or wheezing was improved within 1 or 2 days following the procedure. There were 32% and 22% respective increase in average FEV1 and FVC. Lung perfusion scan showed 9.6% increase of perfusion in the involved lung. No complications related to the procedure were encountered. During follow-up period of up to 31 months, 2 patients showed tracheal or bronchial restenosis, at 3 and 6 months, retrospectively. There was a distal migration of the stents in one case. During the follow up period after stent insertion, improvement of the obstructive changes and dyspnea persisted in 10 out of 13 patients. The modified Gianturco self-expandable metallic stents may be a good choice for the treatment of tracheobronchial stenosis, either as a primary treatment, or when the reconstruction failed.

Endoscopic suture fixation is associated with reduced migration of esophageal fully covered self-expandable metal stents (FCSEMS).

Science.gov (United States)

Wright, Andrew; Chang, Andrew; Bedi, Aarti Oza; Wamsteker, Erik-Jan; Elta, Grace; Kwon, Richard S; Carrott, Phillip; Elmunzer, B Joseph; Law, Ryan

2017-09-01

Esophageal fully covered self-expandable metal stents (FCSEMS) are indicated for the management of benign and malignant conditions of the esophagus including perforations, leaks, and strictures. FCSEMS are resistant to tissue ingrowth and are removable; however, stent migration occurs in 30-55% of cases. Endoscopic suture fixation of FCSEMS has been utilized to decrease the risk of stent migration though data supporting this practice remain limited. The primary aim of this study was to compare clinical outcomes and migration rate of patients who underwent placement of esophageal FCSEMS with and without endoscopic suture fixation. Our single-center, retrospective, cohort study includes patients who underwent esophageal FCSEMS placement with and without endoscopic suture fixation between January 1, 2012, and November 11, 2015. Baseline patient characteristics, procedural details, and clinical outcomes were abstracted. Logistic regression was performed to identify clinical and technical factors associated with outcomes and stent migration. A total of 51 patients underwent 62 FCSEMS placements, including 21 procedures with endoscopic suture fixation and 41 without. Suture fixation was associated with reduced risk of stent migration (OR 0.13, 95% CI 0.03-0.47). Prior stent migration was associated with significantly higher risk of subsequent migration (OR 6.4, 95% CI 1.6-26.0). Stent migration was associated with lower likelihood of clinical success (OR 0.21, 95% CI 0.06-0.69). There was a trend toward higher clinical success among patients undergoing suture fixation (85.7 vs. 60.9%, p = 0.07). Endoscopic suture fixation of FCSEMS was associated with a reduced stent migration rate. Appropriate patient selection for suture fixation of FCSEMS may lead to reduced migration in high-risk patients.

Safety of endoscopic removal of self-expandable stents after treatment of benign esophageal diseases.

Science.gov (United States)

van Halsema, Emo E; Wong Kee Song, Louis M; Baron, Todd H; Siersema, Peter D; Vleggaar, Frank P; Ginsberg, Gregory G; Shah, Pari M; Fleischer, David E; Ratuapli, Shiva K; Fockens, Paul; Dijkgraaf, Marcel G W; Rando, Giacomo; Repici, Alessandro; van Hooft, Jeanin E

2013-01-01

Temporary placement of self-expandable stents has been increasingly used for the management of benign esophageal diseases. To evaluate the safety of endoscopic removal of esophageal self-expandable stents placed for the treatment of benign esophageal diseases. Multicenter retrospective study. Six tertiary care centers in the United States and Europe. A total of 214 patients with benign esophageal diseases undergoing endoscopic stent removal. Endoscopic stent removal. Endoscopic techniques for stent removal, time to stent removal, and adverse events related to stent removal. A total of 214 patients underwent a total of 329 stent extractions. Stents were mainly placed for refractory strictures (49.2%) and fistulae (49.8%). Of the removed stents, 52% were fully covered self-expandable metal stents (FCSEMSs), 28.6% were partially covered self-expandable metal stents (PCSEMSs), and 19.5% were self-expandable plastic stents. A total of 35 (10.6%) procedure-related adverse events were reported, including 7 (2.1%) major adverse events. Multivariate analysis revealed that use of PCSEMSs (P stent removal. Favorable factors for successful stent removal were FCSEMSs (P ≤ .012) and stent migration (P = .010). No significant associations were found for stent indwelling time (P = .145) and stent embedding (P = .194). Retrospective analysis, only tertiary care centers. With an acceptable major adverse event rate of 2.1%, esophageal stent removal in the setting of benign disease was found to be a safe and feasible procedure. FCSEMSs were more successfully removed than self-expandable plastic stents and PCSEMSs. Adverse events caused by stent removal were not time dependent. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Stone extraction balloon-guided repeat self-expanding metal stent placement

Institute of Scientific and Technical Information of China (English)

Hyung; Hun; Kim; Jeong; Seop; Moon; Soo; Hyung; Ryu; Jung; Hwan; Lee; You; Sun; Kim

2010-01-01

Self-expanding metal stent (SEMS) placement offers safe and effective palliation in patients with upper gastrointestinal obstruction due to a malignancy. Well described complications of SEMS placement include tumor growth, obstruction, and stent migration. SEMS occlusions are treated by SEMS redeployment, argon plasma coagulation application, balloon dilation, and surgical bypass. At our center, we usually place the second SEMS into the first SEMS if there is complete occlusion by the tumor. We discovered a...

Silicone covered vs. Non- covered endotracheal self expandable metallic stent: An experimental study

Energy Technology Data Exchange (ETDEWEB)

Do, Young Soo; Lee, Byung Hee; Kim, Soo Ah; Kim, Kie Hwan; Chin, Soo Yil; Cho, Kyung Ja; Cho, Dae Soon [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1994-10-15

To evaluate pathologic changes of the trachea and the lung after insertion of silicone covered and non covered Gianturco stent in the trachea of dog. Silicone covered(covered) and non covered(bare) Gianturco stent, six in each, were inserted into the tracheal lumen of six consecutive dogs. After 1-10 weeks observation, the dogs were sacrificed and their tracheas and lungs were examined grossly and histopathologically. Serial chest radiographs were performed to evaluate pneumonia and stent migration every 3-5 days. Pneumonia was observed in one of bare stent group and five of covered stent group. Stent migration was noted in three of covered stent group. In bare stent group, the epithelium of the trachea was markedly thickened by hyperplasia and stent was covered by granulation tissue from 6 weeks after stent insertion. Inflammation was focal at contact site between the stent and the trachea. In covered stent group, the epithelium was denuded at multiple areas and there were multifocal squamous metaplasia of the mucosa. Inflammatory reaction of the trachea was diffuse. Inflammatory reaction was more severe and stent migration was more frequent in covered stent group. The use of covered stent in the trachea should be studied further.

Self-expandable metal stent placement versus emergency resection for malignant proximal colon obstructions

NARCIS (Netherlands)

Amelung, F.J.; Draaisma, W.A.; Consten, E.C.; Siersema, P.D.; Borg, F. ter

2017-01-01

BACKGROUND: Traditionally, all patients with a malignant obstruction of the proximal colon (MOPC) are treated with emergency resection. However, recent data suggest that Self-expandable metallic stent (SEMS) placement could lower mortality and morbidity rates. This study therefore aimed to compare

Clinical application of self-expandable metallic stents in the treatment of malignant tracheal stenosis under general anesthesia

International Nuclear Information System (INIS)

Wang Weitao; Shi Haibin; Yang Zhengqiang; Liu Sheng; Zhou Chungao; Zhao Linbo; Xia Jinguo; Li Linsun

2009-01-01

Objective: To evaluate the safety and efficacy of self-expandable metallic stent placement for the treatment of malignant tracheal stenosis under general anesthesia and fluoroscopic guidance. Methods: Under general anesthesia the placement of self-expandable metallic stent was performed in 10 patients with malignant tracheal stenosis, the procedure was completed under fluoroscopic guidance in all patients. Results: Successful tracheal stenting was achieved in all 10 patients. In one patient, a Y-shaped stent was used as the tracheal carina was involved in the airway stenosis. The symptoms of dyspnea and asthma were markedly improved immediately after the implantation of stent in all patients. Conclusion: Tracheal implantation of self-expandable metallic stent under general anesthesia and fluoroscopic guidance is a safe and effective treatment for malignant tracheal stenosis, it can promptly relieve various symptoms caused by malignant tracheal stenosis and obviously improve patient's living quality, therefore,t his technique is of great value in clinical practice. (authors)

Treatment of Pelvic Venous Spur (May-Thurner Syndrome) with Self-Expanding Metallic Endoprostheses

International Nuclear Information System (INIS)

Binkert, Christoph A.; Schoch, Eric; Stuckmann, Gerd; Largiader, Jon; Wigger, Pius; Schoepke, Wolfdietrich; Zollikofer, Christoph L.

1998-01-01

Purpose: The application of self-expanding metallic endoprostheses (stents) to treat symptomatic pelvic venous spurs as an alternative to surgery. Methods: Wallstents with a diameter from 14 to 16 mm and one Cragg stent were placed in the left common iliac vein of eight patients (seven women, one man; mean age 42 years) with a symptomatic pelvic venous spur (left deep venous thrombosis or post-thrombotic leg swelling). Four patients had surgical thrombectomy prior to stent placement. Results: Technical success with immediate reduction of left leg circumference was achieved in all eight patients. A primary patency rate of 100% was observed during an average follow-up of 3 years (range 10-121 months). There were no procedural or stent-related complications. Conclusion: The percutaneous transfemoral placement of self-expanding metallic stents is an effective minimally invasive alternative to surgery in the treatment of symptomatic pelvic venous spur

Removal of self expandable metallic airway stent: A rare case report

Directory of Open Access Journals (Sweden)

Rakesh K Chawla

2013-01-01

Full Text Available Covered self expandable metallic airway stents (SEMS have been used for benign tracheal stenosis, post intubation tracheal stenosis, tracheal burn or trauma, tracheo-broncho-malacia, and extrinsic compression of trachea. Their placement is considered to be permanent, with open surgery the only way to remove the stent, though there are few cases reports of their removal with the bronchoscope, but the complications after their removal are very high. In our patient, one and a half years after placement of SEMS, she developed cough with dyspnoea, video bronchoscopy showed stenosis above the level of stent with granulation tissue inside the stent, stent fracture in lower part and stent migration to right main bronchus, thus she had all conceivable complications of stent placement. The stent was removed with the help of rigid bronchoscope under general anaesthesia. She was discharged the following day. The case is being reported because it was unique in having all the possible complications of stent placement, and rare as we could take out the stent in Toto. Thirdly, the stent could be removed without any complication.

Chemotherapy versus self-expanding metal stent as primary treatment of severe dysphagia from unresectable oesophageal or gastro-oesophageal junction cancer.

Science.gov (United States)

Touchefeu, Yann; Archambeaud, Isabelle; Landi, Bruno; Lièvre, Astrid; Lepère, Céline; Rougier, Philippe; Mitry, Emmanuel

2014-03-01

To compare chemotherapy first (group 1) versus self-expanding metal stent first (group 2) for the management of malignant dysphagia in unresectable oesophageal or gastro-oesophageal junction cancer. Patients from two university hospitals with severe malignant dysphagia (dysphagia score ≥ 2) uneligible for surgery or radiochemotherapy were evaluated retrospectively. Forty-two patients were included in group 1, and 29 in group 2. After 4 weeks, dysphagia scores improved by at least 1 point in 67% of patients in group 1 versus 93% in group 2 (p=0.01); 48% of patients in group 1 were able to eat solid food versus 68% in group 2 (p=0.054). In group 1, a self-expanding metal stent was secondarily placed in 18 patients (42.9%), whereas in group 2 dysphagia required a second self-expanding metal stent placement in 33.3% of patients. Chemotherapy as the first treatment may be a valid option, avoiding self-expanding metal stent insertion in half of the patients. Copyright © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Improvement of quality of life and survival using self-expandable metal stent placement for severe malignant stenosis of the gastric body: a case report

Directory of Open Access Journals (Sweden)

Kumagai Hozumi

2012-09-01

Full Text Available Abstract Introduction Advanced gastric carcinoma often decreases quality of life because of upper gastrointestinal tract stenosis. Self-expandable metal stents have been thought to be an effective, minimally invasive treatment for stenosis. However, the effectiveness of self-expandable metal stent placement for carcinomatous stenosis of the gastric body and antrum has not been clarified, and there have been few reports of such cases. Case presentation A 74-year-old Japanese woman developed stenosis of the gastric body and antrum caused by advanced gastric cancer during first-line chemotherapy. She developed weight loss and poor nutrition due to inadequate intake. Self-expandable metal stent placement for stenosis of the gastric body and antrum ameliorated her symptoms rapidly and improved her general condition and quality of life. Eight days after self-expandable metal stent placement, second-line chemotherapy could be administered safely. Oral intake and nutritional status were maintained for 117 days after self-expandable metal stent placement, and she died of gastric cancer 176 days after self-expandable metal stent placement and initiation of second-line chemotherapy. Conclusions Self-expandable metal stent placement for carcinomatous stenosis in the gastric body and antrum could be an effective therapeutic strategy for patients with inadequate oral uptake. It may provide rapid improvement of the patient’s general condition and oral intake with minimal complications, comparatively long-term symptom relief, and a survival benefit by allowing second-line chemotherapy.

Self-expandable metal stents for relieving malignant colorectal obstruction: short-term safety and efficacy within 30 days of stent procedure in 447 patients

DEFF Research Database (Denmark)

Meisner, Søren; González-Huix, Ferran; Vandervoort, Jo G

2011-01-01

The self-expandable metal stent (SEMS) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery.......The self-expandable metal stent (SEMS) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery....

Self-expandable metal stents for malignant colonic obstruction: data from a retrospective regional SIED-AIGO study.

Science.gov (United States)

Di Mitri, Roberto; Mocciaro, Filippo; Traina, Mario; Montalbano, Luigi Maria; Familiari, Luigi; D'Amore, Fabio; Raimondo, Dario; Virgilio, Clara; Tarantino, Ilaria; Barresi, Luca; Giunta, Marco; Borina, Eleonora; Borruto, Antonino; Marino, Antonino

2014-03-01

Self-expandable metal stents are a non-surgical option for the treatment of symptomatic malignant colorectal obstruction as palliative treatment or as a bridge to surgery. To report data from a regional study on self-expandable metal stent (SEMS) placement for malignant colorectal obstruction. Two hundred and four patients (male 54.9%, mean age of 69.5 ± 14.2) were retrospectively evaluated and data on technical and clinical success, and complications, were analyzed. Technical and clinical success rates were 99% and 94.6% respectively, with 36.7% treated on an emergency basis and 63.3% electively. Palliative treatment was administered to 70.1%, and as a bridge to surgery for 29.9%. Complications were 17 neoplastic ingrowths, 10 stent migrations, and 4 perforations. Palliative treatment was associated with a higher risk of stent ingrowth (p=0.003), and chemotherapy with a lower risk of stent ingrowth (p=0.009). This regional study, although it has certain limitations, confirms the positive role of self-expandable metal stents in the treatment of symptomatic malignant colorectal obstruction, and that chemotherapy decreases the risk of ingrowth. Copyright © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Endoscopic removal and trimming of distal self-expandable metallic biliary stents

Science.gov (United States)

Ishii, Kentaro; Itoi, Takao; Sofuni, Atsushi; Itokawa, Fumihide; Tsuchiya, Takayoshi; Kurihara, Toshio; Tsuji, Shujiro; Ikeuchi, Nobuhito; Umeda, Junko; Moriyasu, Fuminori; Tsuchida, Akihiko

2011-01-01

AIM: To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents (SEMS). METHODS: All SEMS had been placed for distal biliary strictures. Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS (one uncovered and 18 covered) removal had been attempted, and 8 patients in whom stent trimming using argon plasma coagulation (APC) had been attempted at Tokyo Medical University Hospital. The APC settings were: voltage 60-80 W and gas flow at 1.5 L/min. RESULTS: The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d (range, 8-280 d). Of the 19 patients in whom removal of the SEMS had been attempted, the procedure was successful in 14 (73.7%) without procedure-related adverse events. The indwelling period in the stent removable group was shorter than that in the unremovable group (94.9 ± 71.5 d vs 166.2 ± 76.2 d, P = 0.08). Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage. Trimming time ranged from 11 to 16 min. CONCLUSION: Although further investigations on larger numbers of cases are necessary to accumulate evidence, the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications. PMID:21677835

Outcome of self-expanding metal stenting followed by radiation therapy for unresectable extrahepatic bile duct cancer

International Nuclear Information System (INIS)

Jin Jing; Gao Li; Yu Zihao; Han Jianzhu; Zhai Renyou

2007-01-01

Objective: To retrospectively analyze the efficacy for self-expanding metal stenting followed by radiation therapy for unresectable extrahepatic bile duct cancer. Methods: From Jan 1996 to Sep 2002, 17 patients were treated with self-expanding metal stenting followed by Ir 192 high dose brachytherapy (brachytherapy group, n=5)and by external beam radiation therapy(external radiation therapy group, n=9). Brachytherapy was delivered on the same day or the following day after stenting with the total dose of DT 20- 30 Gy, twice daily, for 2-3 days. The median total dosage of external radiation therapy was 48 Gy (14-66 Gy), 2 Gy/fraction. Results: Jaundice was released after metal stenting from 71.4% to 14.3% (P=0.001), showing no significant difference between brachytherapy and external radiation therapy in terms of jaundice release(χ 2 =0.21, P=0.65). The median survival period(5-35 months)for whole groups was 12 months 1-, 2-year survival rates were 40.8% and 8.16%, respectively. No significant difference was shown for patients received either brachytherapy or external radiation therapy for 8 months, but with 1,2 year survival rate as 40.0%, 13.3%, respectively (χ 2 =1.10, P=0.29). Conclusions: Self-expanding metal stenting is able to release jaundice significantly and followed by high dose radiation therapy may further prolong the survival. (authors)

A US Multicenter Study of Safety and Efficacy of Fully Covered Self-Expandable Metallic Stents in Benign Extrahepatic Biliary Strictures.

Science.gov (United States)

Saxena, Payal; Diehl, David L; Kumbhari, Vivek; Shieh, Frederick; Buscaglia, Jonathan M; Sze, Wilson; Kapoor, Sumit; Komanduri, Srinadh; Nasr, John; Shin, Eun Ji; Singh, Vikesh; Lennon, Anne Marie; Kalloo, Anthony N; Khashab, Mouen A

2015-11-01

Endoscopic therapy is considered first line for management of benign biliary strictures (BBSs). Placement of plastic stents has been effective but limited by their short-term patency and need for repeated procedures. Fully covered self-expandable metallic stents (FCSEMSs) offer longer-lasting biliary drainage without the need for frequent exchanges. The aim of this study was to assess the efficacy and safety of FCSEMS in patients with BBS. A retrospective review of all patients who underwent ERCP and FCSEMS placement at five tertiary referral US hospitals was performed. Stricture resolution and adverse events related to ERCP and/or stenting were recorded. A total of 123 patients underwent FCSEMS placement for BBS and 112 underwent a subsequent follow-up ERCP. The mean age was 62 years (±15.6), and 57% were males. Stricture resolution occurred in 81% of patients after a mean of 1.2 stenting procedures (mean stent dwell time 24.4 ± 2.3 weeks), with a mean follow-up of 18.5 months. Stricture recurrence occurred in 5 patients, and 3 patients required surgery for treatment of refractory strictures. Stent migration (9.7%) was the most common complication, followed by stent occlusion (4.9%), cholangitis (4.1%), and pancreatitis (3.3%). There was one case of stent fracture during removal, and one stent could not be removed. There was one death due to cholangitis. Majority of BBS can be successfully managed with 1-2 consecutive FCSEMS with stent dwell time of 6 months.

Self-expandable metallic stents for patients with recurrent esophageal carcinoma after failure of primary chemoradiotherapy

Energy Technology Data Exchange (ETDEWEB)

Muto, Manabu; Ohtsu, Atsushi; Boku, Narikazu; Yoshida, Shigeaki [National Cancer Center, Kashiwa, Chiba (Japan). Hospital East; Miyata, Yoshinori; Shioyama, Yasukazu

2001-06-01

Recent advances in chemoradiotherapy for esophageal carcinoma have resulted in improved survival rates. However, there are few options for recurrent dysphagia due to refractory carcinoma after failure of primary chemoradiotherapy. The aim of this study was to evaluate the safety and efficacy of self-expandable metallic stent placement for patients with recurrent esophageal carcinoma where definitive chemoradiotherapy has failed. Thirteen consecutive patients with recurrent squamous cell carcinoma of the esophagus, in whom self-expandable metallic stents were placed after failure of primary chemoradiotherapy, were studied retrospectively. All patients had esophageal obstruction or malignant fistula. The oral alimentation status of nine of 13 patients (69%) improved after successful placement of the stent. Following placement of the stent, fever (>38 deg C) and severe chest pain occurred in 85% (11/13) of the patients. In all patients examined, C-reactive protein was elevated within 1 week of the operation. Esophageal perforation occurred in three patients. Stent-related mediastinitis and pneumonia developed in six (46%) and three (23%) patients, respectively. Seven of the 13 patients (54%) died of stent-related pulmonary complications. Although the placement of a self-expandable metallic stent for patients with recurrent esophageal carcinoma after failure of chemoradiotherapy improved their oral alimentation status, we found that this treatment increases the risk of life-threatening pulmonary complications. (author)

Self-expandable metallic stents for patients with recurrent esophageal carcinoma after failure of primary chemoradiotherapy

International Nuclear Information System (INIS)

Muto, Manabu; Ohtsu, Atsushi; Boku, Narikazu; Yoshida, Shigeaki; Miyata, Yoshinori; Shioyama, Yasukazu

2001-01-01

Recent advances in chemoradiotherapy for esophageal carcinoma have resulted in improved survival rates. However, there are few options for recurrent dysphagia due to refractory carcinoma after failure of primary chemoradiotherapy. The aim of this study was to evaluate the safety and efficacy of self-expandable metallic stent placement for patients with recurrent esophageal carcinoma where definitive chemoradiotherapy has failed. Thirteen consecutive patients with recurrent squamous cell carcinoma of the esophagus, in whom self-expandable metallic stents were placed after failure of primary chemoradiotherapy, were studied retrospectively. All patients had esophageal obstruction or malignant fistula. The oral alimentation status of nine of 13 patients (69%) improved after successful placement of the stent. Following placement of the stent, fever (>38 deg C) and severe chest pain occurred in 85% (11/13) of the patients. In all patients examined, C-reactive protein was elevated within 1 week of the operation. Esophageal perforation occurred in three patients. Stent-related mediastinitis and pneumonia developed in six (46%) and three (23%) patients, respectively. Seven of the 13 patients (54%) died of stent-related pulmonary complications. Although the placement of a self-expandable metallic stent for patients with recurrent esophageal carcinoma after failure of chemoradiotherapy improved their oral alimentation status, we found that this treatment increases the risk of life-threatening pulmonary complications. (author)

Comparison of Self-Expanding Polyethylene Terephthalate and Metallic Stents Implanted in Porcine Iliac Arteries

International Nuclear Information System (INIS)

Wilczek, Krzysztof; Scheerder, Ivan de; Wang Kai; Verbeken, Eric; Piessens, Jan

1996-01-01

Purpose: Comparison of the biocompatibility of self-expanding polyethylene terephthalate (PET) stents with self-expanding metallic stents (Wallstents). Methods: Diameter- and length-matched PET stents and Wallstents were symmetrically implanted in the paired iliac arteries of 13 crossbred domestic swine. Stent deployment was studied angiographically and with intravascular ultrasound immediately after stent implantation. The angiographic stented lumen diameter was measured using quantitative vessel analysis before, immediately after stenting, and at 6-week follow-up. Cross-section histopathology and area morphometry were performed. Results: Immediately poststenting, intravascular ultrasound revealed proximal dislocation of 5 of the 13 PET stents, whereas all metal stents were firmly embedded at the implantation site. At 6-week follow-up, three of the remaining PET stents were totally or subtotally occluded by organized thrombus, whereas all metal stents were patent. Compared with immediately poststenting, the angiographic lumen diameter within the five remaining PET stents was reduced by 30%, and that of the metallic stents was virtually unaltered (p < 0.02). This observation was confirmed by postmortem morphometry, wherein the PET-stented vessel segments a diameter stenosis of 40% was measured vs only 9% in the metallic stents (p < 0.0001). Conclusion: PET-stent deployment is difficult to control due to the lack of radiopacity of this stent. PET stents seem to be more thrombogenic and lead to significantly more neointimal proliferation than metallic stents

Complication after self expandable metallic stent for esophageal cancer

International Nuclear Information System (INIS)

Nagahama, Takeshi; Maruyama, Michio; Kato, Kiyomi; Shinoura, Hiroshi; Hasegawa, Kumi; Takashima, Itaru; Ebuchi, Masakazu

2003-01-01

Major complications after placement of esophageal stent and airway stent were reviewed and evaluated. Four patients, including two patients with perforations and two patients with fistula formation, developed major complications after placement of a self expandable metallic stent. Two patients underwent additional radiation to improve stricture after stent placement. In one patient, stent placement was selected to improve esophageal stricture that occurred after radical radiation therapy. In one patient, migration of stent into the lesion caused a perforation. It can be concluded that additional radiation after stent placement increases the risk of complication. Stent migration also can lead to the risk of perforation. (author)

Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

International Nuclear Information System (INIS)

Han, Young-Min; Kwak, Hyo-Sung; Jin, Gong-Yong; Lee, Seung-Ok; Chung, Gyung-Ho

2007-01-01

We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50 80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2 81 weeks). Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates

Treatment of Malignant Biliary Obstruction with a PTFE-Covered Self-Expandable Nitinol Stent

Energy Technology Data Exchange (ETDEWEB)

Han, Young-Min; Kwak, Hyo-Sung; Jin, Gong-Yong; Lee, Seung-Ok; Chung, Gyung-Ho [Chonbuk National University Medical School and Hospital, Chonju (Korea, Republic of)

2007-10-15

We wanted to determine the technical and clinical efficacy of using a PTFE-covered self-expandable nitinol stent for the palliative treatment of malignant biliary obstruction. Thirty-seven patients with common bile duct strictures caused by malignant disease were treated by placing a total of 37 nitinol PTFE stents. These stents were covered with PTFE with the exception of the last 5 mm at each end; the stent had an unconstrained diameter of 10 mm and a total length of 50 80 mm. The patient survival rate and stent patency rate were calculated by performing Kaplan-Meier survival analysis. The bilirubin, serum amylase and lipase levels before and after stent placement were measured and then compared using a Wilcoxon signed-rank test. The average follow-up duration was 27.9 weeks (range: 2 81 weeks). Placement was successful in all cases. Seventy-six percent of the patients (28/37) experienced adequate palliative drainage for the remainder of their lives. There were no immediate complications. Three patients demonstrated stent sludge occlusion that required PTBD (percutaneous transhepatic biliary drainage) irrigation. Two patients experienced delayed stent migration with stone formation at 7 and 27 weeks of follow-up, respectively. Stent insertion resulted in acute elevations of the amylase and lipase levels one day after stent insertion in 11 patients in spite of performing endoscopic sphincterotomy (4/6). The bilirubin levels were significantly reduced one week after stent insertion (p < 0.01). The 30-day mortality rate was 8% (3/37), and the survival rates were 49% and 27% at 20 and 50 weeks, respectively. The primary stent patency rates were 85%, and 78% at 20 and 50 weeks, respectively. The PTFE-covered self-expandable nitinol stent is safe to use with acceptable complication rates. This study is similar to the previous studies with regard to comparing the patency rates and survival rates.

Hemodialysis shunts-related subclavian vein stenosis : treatment with self-expandable metallic stent

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Gyee; Lee, Young Chul; Shin, Sang Soo; Kim, Yun Hyeon; Kim, Jae Kyu; Kang, Heoung Keun; Jeong, Sang Young; Choi, Su Jin Na [Chonnam Univ. College of Medicine, Kwangju (Korea, Republic of)

1999-04-01

To evaluate the usefulness of placement of self-expandable stents in hemodialytic shunt-related subclavian vein stenosis. Self-expandable metallic stent was placed in nine patients with hemodialytic shunt-related subclavian vein stenosis. In seven cases, angioplasty was attempted before stent placement; in five, stents were placed immediately after failed angioplasty; and in two, due to restenosis after angioplasty. Procedures involved a 10mm diameter, 7-10cm length Wallstent in eight cases, and a 10mm diameter, 8cm length Hanaro stent in one. In all cases, clinical follow-up, which included physical examination and the measurement of venous resistance pressure during hemodialysis, was performed. The follow-up period was between 5 months and 1 year 7 months. Repeated intervention was performed if restenosis was detected. The stenotic sites were in eight cases the site of a previous subclavian venous line, and in one, the site of anatomic narrowing at the thoracic inlet of the subclavian vein. The technical success rate was 100%;a resulting complication was stent migration into the right atrium in one case in which a Hanaro stent had been used; this was removed by snaring. During follow-up of the eight patients in whon stent placement was successful, restenosis developed in three cases. This occurred during the 7th, 8th, and 15th month, respectively. Two such cases were treated by balloon dilatation. In hemodialytic shunt-related subclavian vein stenosis, treatment involving the use of a self-expandable metallic stent is useful, especially for treating a lesion which has not responded to angioplasty with a high patency rate.

Hemodialysis shunts-related subclavian vein stenosis : treatment with self-expandable metallic stent

International Nuclear Information System (INIS)

Kim, Sang Gyee; Lee, Young Chul; Shin, Sang Soo; Kim, Yun Hyeon; Kim, Jae Kyu; Kang, Heoung Keun; Jeong, Sang Young; Choi, Su Jin Na

1999-01-01

To evaluate the usefulness of placement of self-expandable stents in hemodialytic shunt-related subclavian vein stenosis. Self-expandable metallic stent was placed in nine patients with hemodialytic shunt-related subclavian vein stenosis. In seven cases, angioplasty was attempted before stent placement; in five, stents were placed immediately after failed angioplasty; and in two, due to restenosis after angioplasty. Procedures involved a 10mm diameter, 7-10cm length Wallstent in eight cases, and a 10mm diameter, 8cm length Hanaro stent in one. In all cases, clinical follow-up, which included physical examination and the measurement of venous resistance pressure during hemodialysis, was performed. The follow-up period was between 5 months and 1 year 7 months. Repeated intervention was performed if restenosis was detected. The stenotic sites were in eight cases the site of a previous subclavian venous line, and in one, the site of anatomic narrowing at the thoracic inlet of the subclavian vein. The technical success rate was 100%;a resulting complication was stent migration into the right atrium in one case in which a Hanaro stent had been used; this was removed by snaring. During follow-up of the eight patients in whon stent placement was successful, restenosis developed in three cases. This occurred during the 7th, 8th, and 15th month, respectively. Two such cases were treated by balloon dilatation. In hemodialytic shunt-related subclavian vein stenosis, treatment involving the use of a self-expandable metallic stent is useful, especially for treating a lesion which has not responded to angioplasty with a high patency rate

Self-expandable metal stent placement in a child for treatment of achalasia after failed Heller myotomy.

Science.gov (United States)

Gugig, Roberto; Muñoz Jurado, Guillermo; Huang, Clifton; Oleas, Roberto; Robles-Medranda, Carlos

2018-01-01

Background and study aims  Childhood achalasia treatment remains inconclusive. What is next after myotomy failure? Repeated pneumatic-dilation put patients at greater risk of perforation with possible symptom recurrence. We report on a 12-year-old patient with a 1-year history of achalasia whom underwent Heller myotomy with fundoplication and recurred with symptoms 1 week after surgery. Pneumatic dilatation was considered but not done because of the risk of esophageal perforation. The decision was made to place a fully covered self-expanding metallic stent (FC-SEMS) for 3 months, which resolved the stenosis as confirmed by esophagram. The patient has remained asymptomatic since the procedure was performed 2 years ago. FC-SEMS is an alternative for treatment of refractory achalasia in children who do not respond to conventional treatment.

Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis

OpenAIRE

Dahlqvist, Caroline; Ocak, Sebahat; Gourdin, Maximilien; Dincq, Anne Sophie; Putz, Laurie; d’Odémont, Jean-Paul

2016-01-01

Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea) were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation), and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent’s toleranc...

Membranous obstruction of inferior vena cava(MOIVC): treatment with percutaneous transluminal angioplasty(PTA) and self expandable metallic stent

Energy Technology Data Exchange (ETDEWEB)

Lee, Ki Yeol; Kim, Baek Hyun; Cha, In Ho; Lee, Nam Joon; Kim, Yun Hwan; Kim, Jung Hyuk [College of Medicine, Korea University, Seoul (Korea, Republic of)

1994-03-15

Percutaneous transluminal angioplasty(PTA) with a balloon catheter is a standard method of treatment for membranous obstruction of inferior vena cava(MOIVC). But, correct therapeutic approach has not been established for MOIVC patients whose lesion is associated with extensive thrombotic IVC occlusion. We tried to treat MOIVC associated with or without thrombus. We treated 13 cases of MOIVC(associated with thrombus in 7 cases, no thrombus in 6 cases) with PTA, thrombolysis and self-expandable metallic stents. PTA was successful in 8 cases, but failed in 5 cases. The recurred cases were retreated with PTA, but follow-up study revealed recoiling restenosis in 4 cases and intimal hyperplasia in 1 case at previous PTA site which could be overcome with a self-expandable metallic stent. The complication were occurred in 3 cases which were hemothorax, hemopericardium, and hemoperitoneum respectively. However, those were resolved by conservative treatment only. Recanalization and dilatation could be done in MOIVC patients with or without thrombosis for improvement of patient's symptom. Gianturco self-expandable metallic stent is useful in treatment of recurred MOIVC after balloon dilatation and preventing reocclusion of the IVC after PTA.

Self-expandable metal stents for malignant gastric outlet obstruction: A pooled analysis of prospective literature

NARCIS (Netherlands)

van Halsema, Emo E.; Rauws, Erik A. J.; Fockens, Paul; van Hooft, Jeanin E.

2015-01-01

To provide an overview of the clinical outcomes of self-expandable metal stent (SEMS) placement for malignant gastric outlet obstruction (MGOO). A systematic literature search was performed in PubMed of the literature published between January 2009 and March 2015. Only prospective studies that

Biocompatibility of a new device of self-expandable covered and non-covered tracheal stent: comparative study in rats

Directory of Open Access Journals (Sweden)

Olavo Ribeiro Rodrigues

2013-01-01

Full Text Available PURPOSE: To investigate the compatibility of a new model of self-expandable tracheal stent in rats. METHODS: A new device of polyurethane covered and non - covered stent was placed in the trachea of Wistar rats. Animals were distributed in two groups: the polyurethane covered and non-covered group. Macroscopic parameters included position within the tracheal lumen, adherence to the mucosa, degree of dilatation, permeability and internal diameter. Microscopic findings evaluated were: incorporation, inflammatory activity, granulation tissue and epithelial revetment injuries. The observation follow-up was six weeks. All parameters were quantified based on determined score values. Incorporation of the stents was evaluated based on the observation if the stent was fixed into the trachea or if it could be removed. Degree of dilatation was performed by external diameter measurements. Granulation tissue was evaluated by measurements of height of the tissue growing into the tracheal lumen. RESULTS: 100% of non-covered stents had total attachment to mucosa and 100% of polyurethane covered type had adherence only. Regarding dilatation, granulation tissue, inflammatory activity and internal diameter measurements, there were no significant differences between the groups. Pathological tracheal wall injuries were present in both groups. CONCLUSION: Both models of stent demonstrated biocompatibility with the trachea. Rats are suitable for an experimental model of tracheal stent study.

Success and complications of an intra-ductal fully covered self-expanding metal stent (ID-FCSEMS) to treat anastomotic biliary strictures (AS) after orthotopic liver transplantation (OLT).

Science.gov (United States)

Aepli, Patrick; St John, Andrew; Gupta, Saurabh; Hourigan, Luke F; Vaughan, Rhys; Efthymiou, Marios; Kaffes, Arthur

2017-04-01

Anastomotic biliary strictures (AS) after orthotopic liver transplantation (OLT) belong to the most common biliary complications and cause the biggest morbidity burden after OLT. Metal stents for benign biliary strictures are gaining acceptance with many published series. Traditional metal stent designs seem to have poor durability in AS after OLT. Novel intra-ductal stents are showing promise in these strictures. As a result, we designed a special stent with an antimigration waist and a short stent length with a long removal string that rests in the duodenum for easy removal. This is a retrospective multi-centre Australian study of AS after OLT treated with a novel intra-ductal fully covered self-expanding metal stent. From August 2008 to October 2014, records from three liver transplant centres were reviewed. Totally 36 ID-FCSEMS were inserted in 31 cases to treat an AS after OLT. The mean age of the patients was 56 years, and 61 % were male. The mean time of AS presentation after OLT was 20.3 months. Eight out of our 31 patients were previously treated using multiple plastic stenting over time without any success. Treatment with the ID-FCSEMS was performed with an average treatment time of 3.8 months. Stricture resolution was achieved in 100 %. All attempted stents removals were successful without any difficulty. Complications were reported in 6.5 %. It was pleasing that only one case of stent migration (2.8 %) was seen. Follow-up showed seven cases of AS recurrence (24.1 %), and all were treated successfully with repeat ERCP and stenting (some metal, some plastic). This novel ID-FCSEMS has a high clinical success and low complication rate, and in particular, there was only one case of stent migration. As a result, this stent type is preferred to traditional metal stents for treating AS after OLT.

Self-expanding oesophageal metal stents for the palliation of dysphagia due to extrinsic compression

Energy Technology Data Exchange (ETDEWEB)

Gupta, N.K.; Boylan, C.E.; Razzaq, R.; England, R.E.; Mirra, L.; Martin, D.F. [Dept. of Radiology, South Manchester University Hospitals NHS Trust, Withington Hospital (United Kingdom)

1999-07-01

The role of self-expanding metallic stents is well established in the palliation of oesophageal stenosis and dysphagia due to primary oesophageal malignancy. However, their role in palliation of dysphagia due to external compressive mediastinal malignancies is not well established. The purpose of this study was to assess the efficacy of self-expanding metallic stents in the palliation of dysphagia due to extrinsic oesophageal compression by mediastinal malignancy. Between January 1995 and January 1998, 21 patients with oesophageal compression due to malignant mediastinal tumours underwent oesophageal stent placement for palliation of dysphagia. Complete data were available in 17 patients (10 men and 7 women). The mean age was 63.5 years (range 46-89 years). A total of 19 stents were placed successfully. The dysphagia grade prior to and after oesophageal stent placement was assessed and the complications documented. Of the 17 patients, 16 reported an improvement in dysphagia. The mean dysphagia score improved from 3.1 prior to treatment to 1.3 after treatment. In 1 patient the stent slipped during placement and another stent was placed satisfactorily. Early complications (within 48 h) in the form of mild to moderate retrosternal chest pain occurred in 5 patients. This was treated symptomatically. Late complications (after 48 h) in the form of bolus impaction occurred in 2 patients. This was successfully treated with oesophagoscopy and removal of bolus. In 2 patients the stent was overgrown by tumour and in one of these an additional stent was placed. In 1 patient incomplete closure of a tracheo-oesophageal fistula was observed. There was no procedure- or stent-related mortality. The mean survival time of this group was 2.1 months. Self-expanding metallic stents can be safely and effectively used in the palliation of dysphagia due to external mediastinal malignancies. (orig.)

Self-expanding oesophageal metal stents for the palliation of dysphagia due to extrinsic compression

International Nuclear Information System (INIS)

Gupta, N.K.; Boylan, C.E.; Razzaq, R.; England, R.E.; Mirra, L.; Martin, D.F.

1999-01-01

The role of self-expanding metallic stents is well established in the palliation of oesophageal stenosis and dysphagia due to primary oesophageal malignancy. However, their role in palliation of dysphagia due to external compressive mediastinal malignancies is not well established. The purpose of this study was to assess the efficacy of self-expanding metallic stents in the palliation of dysphagia due to extrinsic oesophageal compression by mediastinal malignancy. Between January 1995 and January 1998, 21 patients with oesophageal compression due to malignant mediastinal tumours underwent oesophageal stent placement for palliation of dysphagia. Complete data were available in 17 patients (10 men and 7 women). The mean age was 63.5 years (range 46-89 years). A total of 19 stents were placed successfully. The dysphagia grade prior to and after oesophageal stent placement was assessed and the complications documented. Of the 17 patients, 16 reported an improvement in dysphagia. The mean dysphagia score improved from 3.1 prior to treatment to 1.3 after treatment. In 1 patient the stent slipped during placement and another stent was placed satisfactorily. Early complications (within 48 h) in the form of mild to moderate retrosternal chest pain occurred in 5 patients. This was treated symptomatically. Late complications (after 48 h) in the form of bolus impaction occurred in 2 patients. This was successfully treated with oesophagoscopy and removal of bolus. In 2 patients the stent was overgrown by tumour and in one of these an additional stent was placed. In 1 patient incomplete closure of a tracheo-oesophageal fistula was observed. There was no procedure- or stent-related mortality. The mean survival time of this group was 2.1 months. Self-expanding metallic stents can be safely and effectively used in the palliation of dysphagia due to external mediastinal malignancies. (orig.)

Bronchobiliary Fistula Treated by Self-expanding ePTFE-Covered Nitinol Stent-Graft

International Nuclear Information System (INIS)

Gandini, Roberto; Konda, Daniel; Tisone, Giuseppe; Pipitone, Vincenzo; Anselmo, Alessandro; Simonetti, Giovanni

2005-01-01

A 71-year-old man, who had undergone right hepatectomy extended to the caudate lobe with terminolateral Roux-en-Y left hepatojejunostomy for a Klatskin tumor, developed bilioptysis 3 weeks postoperatively due to bronchobiliary fistula. Percutaneous transhepatic cholangiography revealed a non-dilated biliary system with contrast medium extravasation to the right subphrenic space through a resected anomalous right posterior segmental duct. After initial unsuccessful internal-external biliary drainage, the fistula was sealed with a VIATORR covered self-expanding nitinol stent-graft placed with its distal uncovered region in the hepatojejunal anastomosis and the proximal ePTFE-lined region in the left hepatic duct. A 10-month follow-up revealed no recurrence of bilioptysis and confirmed the complete exclusion of the bronchobiliary fistula

Reversal of Transjugular Intrahepatic Portosystemic Shunt (TIPS)-Induced Hepatic Encephalopathy Using a Strictured Self-Expanding Covered Stent

International Nuclear Information System (INIS)

Cox, Mitchell W.; Soltes, George D.; Lin, Peter H.; Bush, Ruth L.; Lumsden, Alan B.

2003-01-01

Hepatic encephalopathy is a known complication following percutaneous transjugular intrahepatic portosystemic shunt (TIPS) placement. We describe herein a simple and effective strategy of TIPS revision by creating an intraluminal stricture within a self-expanding covered stent, which is deployed in the portosystemic shunt to reduce the TIPS blood flow. This technique was successful in reversing a TIPS-induced hepatic encephalopathy in our patient

Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study

Science.gov (United States)

Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin

2016-01-01

Background Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. Objective The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. Methods We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Results Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Conclusions Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months. PMID:28507752

Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study.

Science.gov (United States)

Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin; Caca, Karel

2017-04-01

Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months.

Physical property and MR imaging of self-expandable metallic stents

Energy Technology Data Exchange (ETDEWEB)

Roh, Hong Gee; Kang, Sung Gwon; Cho, Young Kook; Kim, Hyung Jin; Lim, Myung Kwan; Cho, Soon Gu; Yoh, Kyu Tong; Suh, Chang Hae [Inha Univ., College of Medicine, Seoul (Korea, Republic of)

1998-09-01

In order to furnish basic information prior to their use, the physical properties of various self-expandable metallic stents and their MR characteristics were evaluated. Four commercially available self-expandable metallic stents-Gianturco-the Rosch, Hanaro, Memotherm, and Wallstent-were used in this study. For evaluation of the physical properties of each, hoop strengths and changes in radii according to the degrees of longitudinal flexion were compared. Stent characteristics seen on MR images were evaluated by measuring magnetic torque and by comparing images obtained in the vascular phantom using SE T1TI, FSE T2WI, and FMPSPGR sequences. These images were analyzed with special emphasis on artifact size and the apparant shepe of the stent. Hoop strength was greatest in the Gianturco-Rosch stent, followed by the Memotherm, Hanaro, and Wallstent. When flexed in the longitudinal axis, the radius of the Hanaro and Memotherm stent decreased slightly as a larger flexion angle was applied. When this was 90 deg, however, the connection of the Gianturco-Rosch stent collapsed. In contrast, the radius of the Wallstent became larger as a larger flexion angle was applied. At the portal of the MR imaging unit, neither the Memotherm nor Wallstent showed deflection; except for a thin hyperintense rim at both ends, their images were excellent, and the lumina of these stents were also clearly seen. In contrast, the Gianturco-Rosch and Hanaro stent demonstrated large deflexion and showed a severe black-hole artifact. As a result, visualization of the stents themselves and their lumina was impossible. The Gianturco-Rosch stent showed greatrer hoop strength than the others. The Wallstent showed good longitudinal flexibility and was thought to be effective in tortuous vessels. For follow-up after placement, especially when the nonferromagnetic Memotherm and Wallstent are used, MR imaging appears to be safe and useful.=20.

Predictors of the patency of self-expandable metallic stents in malignant gastroduodenal obstruction.

Science.gov (United States)

Kim, Seung Han; Chun, Hoon Jai; Yoo, In Kyung; Lee, Jae Min; Nam, Seung Joo; Choi, Hyuk Soon; Kim, Eun Sun; Keum, Bora; Seo, Yeon Seok; Jeen, Yoon Tae; Lee, Hong Sik; Um, Soon Ho; Kim, Chang Duck

2015-08-14

To investigate the predictive factors of self-expandable metallic stent patency after stent placement in patients with inoperable malignant gastroduodenal obstruction. A total of 116 patients underwent stent placements for inoperable malignant gastroduodenal obstruction at a tertiary academic center. Clinical success was defined as acceptable decompression of the obstructive lesion within the malignant gastroduodenal neoplasm. We evaluated patient comorbidities and clinical statuses using the World Health Organization's scoring system and categorized patient responses to chemotherapy using the Response Evaluation Criteria in Solid Tumors criteria. We analyzed the relationships between possible predictive factors and stent patency. Self-expandable metallic stent placement was technically successful in all patients (100%), and the clinical success rate was 84.2%. In a multivariate Cox proportional hazards model, carcinoembryonic antigen (CEA) levels were correlated with a reduction in stent patency [P = 0.006; adjusted hazard ratio (aHR) = 2.92, 95%CI: 1.36-6.25]. Palliative chemotherapy was statistically associated with an increase in stent patency (P = 0.009; aHR = 0.27, 95%CI: 0.10-0.72). CEA levels can easily be measured at the time of stent placement and may help clinicians to predict stent patency and determine the appropriate stent procedure.

Long-term results of percutaneous self-expandable metallic stents in malignant biliary obstruction

International Nuclear Information System (INIS)

Kobashi, Yuko; Hoshikawa, Yoshikazu

2004-01-01

Evaluation of the long-term follow-up data of 155 patients with inoperable malignant biliary obstruction who received percutaneous placement of self expandable metallic stent (EMS) and external beam radiotherapy (EBR) combined with self-expandable metallic stent. One-hundred sixty EMS were inserted in 155 patients with inoperable malignant biliary obstruction. One-hundred forty-three patients (Group A) were inserted EMS alone. Twelve patients (Group B) underwent external radiotherapy (40∼45 Gy) after stent insertion. We compared to the Group A and Group B about survival, stent patency and administration. The mean length of survival for the entire group was 111±87 days, while the mean period of patency for all stents was 103±74. We found no statistically significant difference in patient survival or stent patency periods in regard to the level and cause of obstruction. Prolongation of actuarial survival was observed in Group B (316±231 days) as compared to Group A (126±85 days,). Mean length of survival rate and mean period of stent patency rate were not significantly different in regard to the level, cause of obstruction and each stent. External radiotherapy combined EMS could achieve effective palliation and improve the quality of life in selected patients with malignant biliary obstruction. (author)

Use of Self-Expanding Metallic Ureteral Stents in the Secondary Treatment of Ureteral Stenosis Following Kidney Transplantation.

Science.gov (United States)

Xu, Guibin; Li, Xun; He, Yongzhong; Zhao, Haibo; Yang, Weiqing; Xie, Qingling

2015-10-01

To evaluate the safety and efficacy of self-expanding metal stents in the treatment of ureteral stenosis following kidney transplantation. Seven patients who developed benign stenosis after kidney transplantation were treated by a self-expanding metallic stent implantation from June 2007 to March 2014. All patients had undergone at least one open surgical procedure and one endourologic procedure for treatment of the stenosis. The extent of stenosis varied from 1.2 to 3.7 cm. Ultrasonography, urography, diuretic renography, and urine culture were performed every 3 months after stent insertion. Ureteroscopic examination was performed when needed. Stent placement was technically effective in all cases. The mean operative time was 37 minutes (range, 26-59 minutes). Lower urinary-tract symptoms and the ipsilateral flank pain were common early-stage complications and were greatly relieved after an average of 3 months. The mean follow-up duration was 38 months (range, 13-86 months), and no stent migration or fragmentation was observed. Urothelial hyperplasia occurred in only one patient and was effectively managed with a Double-J stent. Five patients had normal stable renal function; the remaining two had impaired renal function, including one patient with a preoperative renal failure who required dialysis at the end of the follow-up period (36 months). As an alternative to open surgery, implantation of a self-expanding metal stent is a safe and effective treatment for ureteral stenosis in patients who have undergone kidney transplantation.

Management of pancreatic collections with a novel endoscopically placed fully covered self-expandable metal stent: a national experience (with videos).

Science.gov (United States)

Chandran, Sujievvan; Efthymiou, Marios; Kaffes, Arthur; Chen, John Wei; Kwan, Vu; Murray, Michael; Williams, David; Nguyen, Nam Quoc; Tam, William; Welch, Christine; Chong, Andre; Gupta, Saurabh; Devereaux, Ben; Tagkalidis, Peter; Parker, Frank; Vaughan, Rhys

2015-01-01

Recent medical literature on novel lumen-apposing stents for the treatment of pancreatic fluid collections (PFCs) is limited by small numbers, solo operators, and single-center experience. To evaluate a recently developed lumen-apposing, fully covered self-expandable metal stent (FCSEMS) in the management of PFCs. Retrospective case series. Thirteen tertiary and private health care centers across Australia. Forty-seven patients (median age 51 years) who underwent endoscopic management of PFCs. Insertion of FCSEMS after PFC puncture under EUS guidance. A subgroup of 9 patients underwent direct endoscopic necrosectomy. Technical and clinical success rate, adverse event rate. The technical success rate was 53 of 54 patients (98.1%), and the initial clinical success rate was 36 of 47 (76.6%), which was sustained for more than 6 months in 34 of 36 (94.4%). Early adverse events included 4 cases (7.4%) of stent migration during direct endoscopic necrosectomy, 4 cases (7.4%) of sepsis, 1 case (1.9%) of bleeding, and 1 case (1.9%) of stent migration into the fistula tract. Late adverse events were 6 (11.1%) spontaneous stent migrations, 3 (5.6%) recurrent stent occlusions, 3 (5.6%) tissue ingrowth/overgrowth, and 2 (3.7%) bleeding into PFC. The majority of stents inserted (48 of 54, 88.9%) and removed (31 of 35, 88.6%) in our study were described by the operator as superior to pigtail stents with regard to ease of use. Retrospective study. Although FCSEMSs are technically easier to insert and remove compared with traditional pigtail stents, there are significant limitations to the widespread use of FCSEMSs in the management of PFCs. These include cost, adverse events, and lower-than-expected resolution rates. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

[Cost-effectiveness trial of self-expandable metal stents and plastic biliary stents in malignant biliary obstruction].

Science.gov (United States)

Daróczi, Tímea; Bor, Renáta; Fábián, Anna; Szabó, Ella; Farkas, Klaudia; Bálint, Anita; Czakó, László; Rutka, Mariann; Szűcs, Mónika; Milassin, Ágnes; Molnár, Tamás; Szepes, Zoltán

2016-02-14

Self-expandable metal and plastic stents can be applied in the palliative endoscopic treatment of patients with unresectable malignant biliary obstruction. The use of metal stentsis recommended if the patient's life expectancy is more than four months. To compare the therapeutic efficacy and cost-effectiveness of metal and plastic stents in the treatment of malignant biliary obstruction. The authors retrospectively enrolled patients who received metal (37 patients) or plastic stent (37 patients). The complication rate, stent patency and cumulative cost of treatment were assessed in the two groups. The complication rate of metal stents was lower (37.84% vs. 56.76%), but the stent patency was higher compared with plastic stents (19.11 vs. 8.29 weeks; p = 0.0041). In the plastic stent group the frequency of hospitalization of patients in context with stent complications (1.18 vs. 2.32; p = 0.05) and the necessity of reintervention for stent dysfunction (17 vs. 27; p = 0.033) were substantially higher. In this group multiple stent implantation raised the stent patency from 7.68 to 10.75 weeks. There was no difference in the total cost of treatment of malignant biliary obstruction between the two groups (p = 0.848). Considering the cost of treatment and the burden of patients the authors recommend self-expandable metal sten timplantation if the life expectancy of patients is more than two months. In short survival cases multiple plastic stent implantation is recommended.

Self-expandable metal stents for obstructing colonic and extracolonic cancer

DEFF Research Database (Denmark)

van Hooft, Jeanin E; van Halsema, Emo E; Vanbiervliet, Geoffroy

2014-01-01

as a bridge to elective surgery is not recommended as a standard treatment of symptomatic left-sided malignant colonic obstruction (strong recommendation, high quality evidence). 3 For patients with potentially curable but obstructing left-sided colonic cancer, stent placement may be considered......, and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations The following recommendations should only be applied after a thorough diagnostic evaluation including a contrast-enhanced computed tomography (CT) scan. 1 Prophylactic colonic...... stent placement is not recommended. Colonic stenting should be reserved for patients with clinical symptoms and imaging evidence of malignant large-bowel obstruction, without signs of perforation (strong recommendation, low quality evidence). 2 Colonic self-expandable metal stent (SEMS) placement...

How to design the optimal self-expandable oesophageal metallic stents: 22 years of experience in 645 patients with malignant strictures.

Science.gov (United States)

Na, Han Kyu; Song, Ho-Young; Kim, Jin Hyoung; Park, Jung-Hoon; Kang, Min Kyoung; Lee, Jongjin; Oh, Se Jin

2013-03-01

To evaluate the clinical efficacy and safety of self-expandable metallic stent (SEMS) placement for malignant oesophageal strictures and their relationship with stent designs. Seven generations of SEMS were used to treat 645 consecutive patients with oesophageal strictures. Logistic regression models were constructed to identify predictive factors associated with complications. Stent placement was technically successful in 641 of 645 patients (99.4%). The clinical success rate was 95.5%. There were 260 (40.3%) complications after stent placement. Due to complications, 68 stents were removed; 66 of 68 stents (97.1%) were removed successfully. Stainless steel (SS) stents (odds ratio [OR] 4.18; 95% confidence interval [CI] 2.10, 8.32) and radiation therapy (RT) before stent placement (OR 4.23; CI 2.02, 8.83) were significantly associated with severe pain. Flared ends (OR 9.63; CI 3.38, 27.43), stricture length stent diameter stent migration. Polyurethane membranes were associated with more frequent tumour ingrowth than polytetrafluoroethylene (PTFE) membranes (P = 0.002). Despite the relatively high complication rate, retrievable self-expandable PTFE-covered nitinol stents equipped with a head and a tail appeared to be an effective treatment for malignant oesophageal strictures.

Usefulness of a balloon-expandable, covered stent for the transjugular intrahepatic portosystemic shunt

Directory of Open Access Journals (Sweden)

Rössle M

2018-01-01

Full Text Available The availability of polytetrafluoroethylene (PTFE covered, self-expandable nitinol stents in 2001 considerably improved the patency, response rates and survival of the transjugular intrahepatic portosystemic shunt (TIPS. Side effects of portosystemic shunting such as hepatic encephalopathy (HE and worsening of hepatic function, however, remained a problem. To reduce HE, underdilatation of nitinol stents has been practiced for many years. However, as shown recently, underdilatation was a flop since, due to their intrinsic memory, nitinol stents always expanded to reach their nominal diameter of 8 or 10 mm. To overcome this problem and to be able to perform permanent shunts with a smaller diameter of < 8 mm, we studied the usefulness of a balloon-expandable, covered, metallic stent which allowed adjustment to any diameter between 5 and 12 mm. Methods: 30 patients with cirrhosis and symptomatic portal hypertension were included. The mean Child-Pugh score was 8 ± 2.17 patients had refractory ascites, 9 patients variceal bleeding and four patients other indications for the TIPS. Results: The TIPS was successfully implanted in all patients within 69.6 ± 21.8 min. The shunt reduced the portosystemic pressure gradient by 57.5 ± 14.2% with a mean stent diameter of 7.4 ± 1.0 mm (5 -10.3 mm. During a mean follow-up of 330 ± 249 days, shunt revision was necessary in 5 patients (17%, four of them had insufficient response and received stent dilatation and one patient had stent misplacement requiring a parallel shunt. Three patients (10% developed HE. Conclusions: The covered, balloon-expandable stent could be placed accurately and allowed creation of adapted shunts with smaller diameters as usual. This resulted in a comparatively low rate of HE.

A clinical evaluation of endoscopically placed self-expanding metallic stents in patients with acute large bowel obstruction

DEFF Research Database (Denmark)

Pommergaard, H C; Vilmann, P; Jakobsen, H L

2009-01-01

BACKGROUND AND AIMS: Self-expanding metallic stents (SEMS) have since 1991 established themselves as an option in the treatment of large bowel obstruction. The aim of this study was to evaluate the use of SEMS in management of acute colorectal obstructions at a Danish Surgical Gastroenterology...

Endoscopic palliation of patients with biliary obstruction caused by nonresectable hilar cholangiocarcinoma: efficacy of self-expandable metallic Wallstents

NARCIS (Netherlands)

Cheng, John L. S.; Bruno, Marco J.; Bergman, Jacques J.; Rauws, Erik A.; Tytgat, Guido N.; Huibregtse, Kees

2002-01-01

Background: The aim of this study was to evaluate the efficacy of an endoscopically inserted self-expandable metal stent for treatment of biliary obstruction caused by nonresectable hilar cholangiocarcinoma. Methods: Data on all patients with nonresectable hilar cholangiocarcinoma receiving

Self-expandable metallic stent placement for patients with inoperable esophageal carcinoma. Investigation of the influence of prior radiotherapy and chemotherapy

International Nuclear Information System (INIS)

Ihara, Yuko; Murayama, Sadayuki; Toita, Takafumi; Utsunomiya, Takashi; Nagata, Osamu; Akamine, Tamaki; Ogawa, Kazuhiko; Adachi, Genki; Tanigawa, Noboru

2006-01-01

The aim of this study was to evaluate the efficacy and complications of self-expandable metallic stent placement for patients with inoperable esophageal carcinoma after radiotherapy and/or chemotherapy. We obtained data from 19 patients with advanced or recurrent esophageal carcinoma between 1996 and 2000. In all patients, a self-expandable metallic stent was placed under fluoroscopic guidance. Dysphagia before and after stent placement was graded. Complications after stent placement were also evaluated. Data were compared between patients with and without prior radiotherapy and/or chemotherapy. The procedure was technically successful in all but one patient. The dysphagia grade improved in all patients. No life-threatening complications occurred. The other major complications such as mediastinitis occurred in two patients, and pneumonia and funnel phenomenon occurred in one patient each. These patients had a history of radiotherapy and/or chemotherapy prior to stent placement. Eight of the twelve patients with prior radiotherapy and/or chemotherapy compared with one of seven patients without prior therapy had persistent chest pain, which was a statistically significant difference (P<0.05). Placement of self-expandable metallic stents was effective for patients with advanced or recurrent esophageal carcinoma. However, prior irradiation and/or chemotherapy increased the risk of persistent chest pain after stent placement. (author)

Management of post-gastrectomy anastomosis site obstruction with a self-expandable metallic stent.

Science.gov (United States)

Cha, Ra Ri; Lee, Sang Soo; Kim, Hyunjin; Kim, Hong Jun; Kim, Tae-Hyo; Jung, Woon Tae; Lee, Ok Jae; Bae, Kyung Soo; Jeong, Sang-Ho; Ha, Chang Yoon

2015-04-28

Post-gastrectomy anastomosis site obstruction is a relatively rare complication after a subtotal gastrectomy. We present a case of a 75-year-old man who underwent a truncal vagotomy, omental patch, gastrojejunostomy, and Braun anastomosis for duodenal ulcer perforation and a gastric outlet obstruction. Following the 10(th) postoperative day, the patient complained of abdominal discomfort and vomiting. We diagnosed post-gastrectomy anastomosis site obstruction by an upper gastrointestinal series and an upper endoscopic examination. We inserted a self-expandable metallic stent (SEMS) at the anastomosis site. The stent was fully expanded after deployment. On the day following the stent insertion, the patient began to eat, and his abdominal discomfort was resolved. This paper describes the successful management of post-gastrectomy anastomosis site obstruction with temporary placement of a SEMS.

Delayed ischemic cecal perforation despite optimal decompression after placement of a self-expanding metal stent: report of a case

DEFF Research Database (Denmark)

Knop, Filip Krag; Pilsgaard, Bo; Meisner, Søren

2004-01-01

Endoscopic deployment of self-expanding metal stents offers an alternative to surgical intervention in rectocolonic obstructions. Reported clinical failures in the literature are all related to the site of stent placement. We report a case of serious intra-abdominal disease after technically...... and clinically successful stent deployment: a potentially dangerous situation of which the surgeon should be aware. A previously healthy 72-year-old female was referred to our department with symptoms of an obstructing colorectal tumor. Successful stent placement resulted in resolution of the obstructive......, probably caused by ischemic conditions developed before stent-decompression of the colon was revealed during the operation. The patient died in the postoperative course. We discuss the observation of patients treated with self-expanding metal stents based on the selection-strategy used to allocate patients...

Self-Expandable Metal Stent for Closure of a Large Leak after Total Gastrectomy

Directory of Open Access Journals (Sweden)

G. Curcio

2010-08-01

Full Text Available In recent years, self-expandable metallic stents (SEMSs have emerged as a promising treatment alternative for the bridging and sealing of esophageal perforations and extensive anastomotic leaks after esophageal resection or total gastrectomy. A 56-year-old woman underwent a total gastrectomy with Roux-en-Y end-to-side esophagojejunostomy for a gastric signet ring cell carcinoma. Ten days later, esophagogastroduodenoscopy showed a 2 cm fistula in the distal end of the Roux limb of the anastomosis. This was confirmed by gastrografin esophagography. The patient was started on total parenteral nutrition. Having deemed clipping treatment for this fistula unfeasible, we decided to insert a partially silicone-coated SEMS (Evolution Controlled Release Esophageal Stent System, Cook Medical, Winston-Salem, N.C., USA. The stent was removed after ten days. Gastrografin esophagography showed no further contrast extravasation, and esophagogastroduodenoscopy showed closure of the fistula. No clinical complications were observed, and the patient was able to start normal per os nutrition. In conclusion, the treatment of symptomatic leaks in patients who have undergone esophagojejunostomy is challenging, and leakage from the jejunal stump can be a potentially serious complication. In the treatment of leakage after total gastrectomy, plastic stents (which are either too light or exercise too little radial force and totally covered metallic stents may not adhere sufficiently to the esophagojeujunal walls and, as a result, migrate beyond the anastomosis. The promising results of this report suggest that early stenting, using a partially silicone-coated SEMS, is a feasible alternative to surgical treatment in this category of patients.

Self-expandable medical memorial metallic stent with 125I seeds for the treatment of esophageal carcinoma: a retrospective analysis

International Nuclear Information System (INIS)

Zhang Shuo; Lu Bin

2011-01-01

Objective: To discuss the curative effect and safety of the implantation of self-expandable medical memorial metallic stent with 125 I seeds for the treatment of advanced esophageal carcinomas. Methods: Implantation of self-expandable medical memorial metallic stent with 125 I seeds was performed in 32 patients with advanced esophageal canner. The clinical data were retrospectively analyzed. The technical success rate, the operation time, the immediate and mid-term effectiveness, the survival time, the complications, the body weight, the blood picture, the immune indexes, the average hospitalization days and hospitalization expenses were analyzed. Results: The average operation time was (18±5) minutes. Successful stent implantation was achieved in all 32 patients (100%). No 125 I seeds fell off during the procedure. The remission rate of dysphagia was 100%. Esophageal restenosis occurred in four patients, and displacement of the stent was seed in one patient. One month after the treatment, 90% of patients had a Karnofsky performance score over 60. The mean survival time was (8.7±6.6) months. The average hospitalization time was (7.8±3.7) days and the mean hospitalization cost was (12±3) thousand Chinese Yuan. Conclusion: For the treatment of esophageal carcinomas, the implantation of self-expandable medical memorial metallic stent with 125 I seeds is safe, effective and simple. This treatment can markedly improve the symptom of dysphagia and significantly prolong the patient's survival time. (authors)

Malignant inferior vena cava obstruction involving right atrium. Palliative treatment with self expandable metallic stent

International Nuclear Information System (INIS)

Shao Guoliang; Wang Jianhua; Zhou Kangrong; Yan Zhiping

2001-01-01

Objective: To investigate the safety and efficacy of placement of self-expandable metallic stent within right atrium and inferior vena cava (ICV) in patients with malignant ICV obstruction involving right atrium. Methods: There were 5 male patients with advanced hepatocellular carcinoma, aged from 42 to 65 years (mean 56.3 years). The malignancies invaded right atrium and ICV simultaneously, and caused obstruction of ICV. These patients presented symptoms and signs of obstruction of ICV such as hepatomegaly, ascites, edema of lower extremities. 'Z' type stainless steel stents (7.5-10.0 cm in length and 2.5 cm in diameter) were selected for these patients. Part (1.0-3.0 cm in length) of stent was placed in right atrium and the rest was in ICV. Results: All of stents were placed successfully and obstructed ICV reopened. The symptoms of obstruction of ICV relieved or disappeared. There were no recurrence of symptoms of obstruction of ICV and any cardiac complication related to placement of stents in follow-up period (67-188 days). Conclusion: Placement of self-expandable metallic stent within right atrium and ICV in treatment of patients with malignant ICV obstruction involving right atrium is one of the safe and effective methods

Placement of retrievable self-expandable metallic stents with barbs into patients with obstructive prostate cancer.

Science.gov (United States)

Song, Ho-Young; Kim, Choung Soo; Jeong, In Gab; Yoo, Dalsan; Kim, Jin Hyoung; Nam, Deok Ho; Bae, Jae-Ik; Park, Jung-Hoon

2013-03-01

To evaluate the technical feasibility and clinical effectiveness of retrievable self-expandable metallic stents with barbs in patients with obstructive prostate cancer. Retrievable self-expandable metallic stents with eight barbs each were inserted into eight consecutive patients with obstructive prostate cancer. Patient ages ranged from 55 to 76 years (mean, 69 years). All eight patients had previously received hormone therapy, and three had undergone palliative transurethral prostatectomy. Stents were removed using a 21-F stent removal set if they caused complications. Stent placement was technically successful and well tolerated in all patients. One had severe incontinence, which improved spontaneously, and two had gross haematuria, which disappeared spontaneously within 4 days. Peak urine flow rates and post-void residual urine volumes 1 month after stent placement were 5.6-10.2 ml/s (mean, 8.3 ml/s), and 5-45 ml (mean, 27 ml), respectively. During a mean follow-up of 192 days (range, 39-632 days), one patient required stent removal after 232 days because of stone formation within the stent. No further intervention was required because the mass improved after stent removal. These preliminary results suggest that retrievable stents with eight barbs are both feasible to place and effective in patients with obstructive prostate cancer.

A pilot study about the oncologic safety of colonic self-expandable metal stents (SEMS) in obstructive colon cancer: is occlusion always better than "silent" perforation?

Science.gov (United States)

Zanghì, A; Piccolo, G; Cavallaro, A; Pulvirenti, E; Lo Menzo, E; Cardì, F; Di Vita, M; Cappellani, A

2016-12-01

To evaluate the oncologic safety of colonic self-expandable metal stents (SEMS) in obstructive colon cancer. We retrospectively reviewed all the patients who were treated with endoscopic placement of a self-expandable metallic stent (SEMS) at our institution. A total of 26 patients were identified during the study period, of which 24 patients (92.30%) were treated with SEMS as a bridge-to-surgery and 2 (7.69%) as palliation. In 22 cases (80.76%), the stenosis was localized to the left side. Clinical success with resolution of bowel obstructions was achieved in 22 (84.61%) patients within a short period of time. Among patients treated successfully with SEMS insertion as bridge to surgery (n = 22), 20 (90.9%) underwent one-stage surgery with primary anastomosis while 2 patients (9.09%) underwent colostomy due to intraoperative evidence of a covered perforation by cancer tissue in the pelvis. Patients with subclinical perforation developed an early peritoneal carcinomatosis, 10 patients treated with curative intent subsequently developed liver metastasis after 24 months. We reported an overall poor outcome among patients treated with the insertion of SEMS. This led us to think that, in some cases, occlusion may be better than a "silent" perforation.

Effects of the Temporary Placement of a Self-Expandable Metallic Stent in Benign Pyloric Stenosis

OpenAIRE

Choi, Won Jae; Park, Jong-Jae; Park, Jain; Lim, Eun-Hye; Joo, Moon Kyung; Yun, Jae-Won; Noh, Hyejin; Kim, Sung Ho; Choi, Woo Seok; Lee, Beom Jae; Kim, Ji Hoon; Yeon, Jong Eun; Kim, Jae Seon; Byun, Kwan Soo; Bak, Young-Tae

2013-01-01

Background/Aims The use of self-expandable metallic stents (SEMS) is an established palliative treatment for malignant stenosis in the gastrointestinal tract; therefore, its application to benign stenosis is expected to be beneficial because of the more gradual and sustained dilatation in the stenotic portion. We aimed in this prospective observational study to evaluate the efficacy and safety of temporary SEMS placement in benign pyloric stenosis. Methods Twenty-two patients with benign sten...

Understanding the Mechanical forces of Self-Expandable Metal Stents in the Biliary Ducts.

Science.gov (United States)

Isayama, Hiroyuki; Nakai, Yousuke; Hamada, Tsuyoshi; Matsubara, Saburo; Kogure, Hirofumi; Koike, Kazuhiko

2016-12-01

Self-expandable metallic stent (SEMS) was an effective biliary endoprosthesis. Mechanical properties of SEMS, radial and axial force (RF, AF), may play important roles in the bile duct after placement. RF was well known dilation force and influenced on the occurrence of migration. AF, newly proposed by this author, was defined as the recovery force when the SEMS vended. AF was related with the cause of bile duct kinking, pancreatitis, and cholecystitis due to the compression of the bile duct, orifice of the cystic duct, and pancreatic orifice. Ideal SEMS may show high RF and low AF.

Randomized multicenter study of multiple plastic stents vs. covered self-expandable metallic stent in the treatment of biliary stricture in chronic pancreatitis.

Science.gov (United States)

Haapamäki, Carola; Kylänpää, Leena; Udd, Marianne; Lindström, Outi; Grönroos, Juha; Saarela, Arto; Mustonen, Harri; Halttunen, Jorma

2015-07-01

The use of covered self-expandable metallic stents (cSEMS) in benign biliary indications is evolving. The aim of the study was to assess the safety and feasibility of cSEMS compared with multiple plastic stents in the treatment of benign biliary stricture (BBS) caused by chronic pancreatitis. This was a prospective, multicenter, randomized study of 60 patients with BBS caused by chronic pancreatitis. All patients received an initial plastic stent before randomization. At randomization, the stent was replaced either with a single cSEMS or three plastic stents. After 3 months, the position of the cSEMS was checked or another three plastic stents were added. At 6 months after randomization, all stents were removed. Clinical follow-up including abdominal ultrasound and laboratory tests were performed at 6 months and 2 years after stent removal. Two patients dropped out of the cSEMS group before stent removal. In April 2014, the median follow-up was 40 months (range 1 - 66 months). The 2-year, stricture-free success rate was 90 % (95 % confidence interval [CI] 72 % - 97 %) in the plastic stent group and 92 % (95 %CI 70 % - 98 %) in the cSEMS group (P = 0.405). There was one late recurrence in the plastic stent group 50 months after stent removal. Stent migration occurred three times (10 %) in the plastic stent group and twice in the cSEMS group (7 %; P = 1.000). A 6-month treatment with either six 10-Fr plastic stents or with one 10-mm cSEMS produced good long-term relief of biliary stricture caused by chronic pancreatitis.Study registered at ClinicalTrials.gov (NCT01085747). © Georg Thieme Verlag KG Stuttgart · New York.

Management of benign biliary strictures with a novel retrievable self-expandable metal stent.

Science.gov (United States)

Hu, Bing; Leung, Joseph W; Gao, Dao Jian; Wang, Tian Tian; Wu, Jun

2014-03-01

Endoscopic placement of covered self-expandable metal stent (SEMS) has gained popularity in the management of benign biliary strictures (BBS). The existing SEMS has been designed primarily to palliate malignant biliary obstruction and has a high frequency of stent migration, difficulty in retrieval and stricture recurrence after stent removal. This study aimed to design a novel retrievable SEMS dedicated to the treatment of extrahepatic BBS and evaluate its clinical efficacy and safety. A short fully covered SEMS (FCSEMS) with a retrieval lasso was designed for the specific treatment of BBS. A total of 45 patients with segmental extrahepatic BBS were included in this study. The stent was placed entirely inside the bile duct with only the retrieval lasso extending from the papilla. The stents were recommended to be in situ for 6 to 12 months before removal. The FCSEMS was successfully placed in all 45 patients. In all, 33 patients had their FCSEMS successfully removed after a mean period of 8.6 ± 3.7 (range 2-15.5) months. Stent migration occurred in 9.1% of the patients. During a mean follow-up of 18.9 months after stent removal, recurrent stricture was found in 2 (6.1%) patients and was successfully treated with a second FCSEMS. Overall, the strictures resolved in 30/33 (90.9%) patients. Intraductal placement of a short FCSEMS is suitable for the treatment of segmental extrahepatic BBS. This new removable design offered prolonged stenting and drainage for BBS for up to one year with minimal complications. © 2013 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Palliation of Postoperative Gastrointestinal Anastomotic Malignant Strictures with Flexible Covered Metallic Stents: Preliminary Results

International Nuclear Information System (INIS)

Lee, Jeong-Min; Han, Young Min; Lee, Sang Yong; Kim, Chong Soo; Yang, Doo Hyun; Lee, Seung Ok

2001-01-01

Purpose: To evaluate the efficacy of the placement of covered metallic stents for palliation of gastrointestinal anastomotic strictures secondary to recurrent gastric cancer.Methods: Under fluoroscopic guidance, placement of one or two self-expandable covered metallic stents was attempted perorally in 11 patents (aged 48-76 years) with anastomotic stenoses due to recurrent gastric malignancies. The strictures involved both the afferent and efferent loops in three patients. All patients had poor peroral food intake with severe nausea and vomiting after ingestion. The technical and clinical success was evaluated.Results: Placement of the covered stent was technically successful in 13 of 15 (87%) attempts in ten patients. After the procedure, 9 of 11 (82%) patients overall were able to ingest at least a liquid diet and had markedly decreased incidence of vomiting. During the follow-up of 2-31 weeks (mean 8.5 weeks) there were no major complications.Conclusion: These preliminary results suggest that flexible, covered stents may provide effective palliation of malignant anastomotic stricture secondary to recurrent gastric cancer

The integrated place of tracheobronchial stents in the multidisciplinary management of large post-pneumonectomy fistulas: our experience using a novel customised conical self-expandable metallic stent.

Science.gov (United States)

Dutau, Hervé; Breen, David Patrick; Gomez, Carine; Thomas, Pascal Alexandre; Vergnon, Jean-Michel

2011-02-01

Stump dehiscence after pneumonectomy is a cause of morbidity and mortality in patients treated for non-small-cell lung carcinoma. Surgical repair remains the treatment of choice but can be postponed or contraindicated. Bronchoscopic techniques may be an option with curative intent or as a bridge towards definitive surgery. The aim of the study is to evaluate the efficacy and the outcome of a new customised covered conical self-expandable metallic stent in the management of large bronchopleural fistulas complicating pneumonectomies. A case series using chart review of non-operable patients presenting with large bronchopleural fistulas (>6mm) post-pneumonectomies as a definitive treatment with curative intent for non-small-cell lung carcinomas and requiring the use of a dedicated conical shaped stent in two tertiary referral centres. Seven patients presenting large post-pneumonectomy fistulas (between 6 and 12 mm) were included. Cessation of the air leak and clinical improvement was achieved in all the patients after stent placement. Stent-related complications (two migrations and one stent rupture) were successfully managed using bronchoscopic techniques in two patients and surgery in one. Mortality, mainly related to overwhelming sepsis, was 57%. Delayed definitive surgery was achieved successfully in three patients (43%). This case series assesses the short-term clinical efficacy of a new customised covered conical self-expandable metallic stent in the multidisciplinary management of large bronchopleural fistulas complicating pneumonectomies in patients deemed non-operable. Long-term benefits are jeopardised by infectious complications. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Insertion of self-expanding metal stent for treatment of malignant obstruction in a pregnant woman

Directory of Open Access Journals (Sweden)

Noelia Alonso-Lázaro

2014-03-01

Full Text Available Colorectal cancer (CRC is the second most frequent cancer both in incidence and mortality in women, especially in those over 60 years of age. Diagnosis in women at gestational age is rare, so its incidence during pregnancy is low. However, an increase in its diagnosis is expected during the next years because of the raise in the average age of pregnancy. In most cases, the diagnosis is delayed because symptoms related to CRC can be attributed to pregnancy itself. Up to 30 % of CRC cases may present as an intestinal obstruction. In this situation, the main objective is to solve the clinical emergency in the safest way for mother and fetus, together with performing an accurate diagnostic approach to offer the best possible therapeutic management knowing the limitations and difficulties related to pregnancy. The self-expanding metallic stent (SEMS can be particularly useful in colon obstruction in a pregnant patient with CRC because it allows solving the acute condition providing time to perform a more accurate staging study and to prepare the patient for surgery, thus reducing both post-surgical morbidity and mortality. We report on the case of a patient who early in the second trimester of pregnancy presented with an acute colonic obstruction due to CRC which was successfully managed with the placement of a self-expanding metal stent.

Fully covered stents versus partially covered stents for palliative treatment of esophageal cancer: Is there a difference?

Science.gov (United States)

Alonso Lárraga, J O; Flores Carmona, D Y; Hernández Guerrero, A; Ramírez Solís, M E; de la Mora Levy, J G; Sánchez Del Monte, J C

2018-02-26

Malignant dysphagia is difficulty swallowing resulting from esophageal obstruction due to cancer. The goal of palliative treatment is to reduce the dysphagia and improve oral dietary intake. Self-expandable metallic stents are the current treatment of choice, given that they enable the immediate restoration of oral intake. The aim of the present study was to describe the results of using totally covered and partially covered esophageal stents for palliating esophageal cancer. A retrospective study was conducted on patients with inoperable esophageal cancer treated with self-expandable metallic stents. The 2 groups formed were: group A, which consisted of patients with a fully covered self-expandable stent (SX-ELLA ® ), and group B, which was made up of patients with a partially covered self-expandable stent (Ultraflex ® ). Of the 69-patient total, 50 were included in the study. Group A had 19 men and 2 women and their mean age was 63.6 years (range 41-84). Technical success was achieved in 100% (n=21) of the cases and clinical success in 90.4% (n=19). Group B had 24 men and 5 women and their mean age was 67.5 years (range 43-92). Technical success was achieved in 100% (n=29) of the cases and clinical success in 89.6% (n=26). Complications were similar in both groups (33.3 vs. 51.7%). There was no difference between the 2 types of stent for the palliative treatment of esophageal cancer with respect to technical success, clinical success, or complications. Copyright © 2018 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma México S.A. All rights reserved.

Insertion of a self-expandable metallic stent in canine lacrimal Sac : a long-term evaluation

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young; Sung, Kyu Bo; Yoon, Hyun Ki [Univ. of Ulsan, Ulsan (Korea, Republic of). College of Medicine; Kwon, Soon Tae [Chungnam National Univ., Taejon (Korea, Republic of). Medical School; Lee, Ho Jung; Lee, In Chul; Kim, Tae Hyung; Park, Sang Soo; Huh, Soo Jin [Univ. of Ulsan, Ulsan (Korea, Republic of). College of Medicine

1998-01-01

To evaluate the feasibility and long-term outcome of the use of self-expandable metallic Z-stents in the canine lacrimal sac. Stent placement was technically successful and well tolerated in all but one lacrimal sac, in which the stent was misplaced. At three and six months after stent placement, stent wires were not encased by epithelium, but at nine months, and one, two and three years after placement, six of the 12 stents had become encased in a proliferation of this where the stent wires contacted the lacrimal sac wall. In no lacrimal system in which stent placement had been successful was migration, stenosis or obstruction of the lacrimal system observed. One misplaced stent caused obstruction of the lacrimal sac, however . In 11 of 12 case (92%), fluoroscopic placement of an expandable metallic stent in the canine lacrimal sac was successful: in 6 of 8 cases (75%), the stent wires became encased by a proliferation of mucosa, but during long-term follow-up of 9 months to 3 years, no obstruction was observed. (author). 20 refs., 1 tab., 5 figs.

Insertion of a self-expandable metallic stent in canine lacrimal Sac : a long-term evaluation

International Nuclear Information System (INIS)

Song, Ho Young; Sung, Kyu Bo; Yoon, Hyun Ki; Kwon, Soon Tae; Lee, Ho Jung; Lee, In Chul; Kim, Tae Hyung; Park, Sang Soo; Huh, Soo Jin

1998-01-01

To evaluate the feasibility and long-term outcome of the use of self-expandable metallic Z-stents in the canine lacrimal sac. Stent placement was technically successful and well tolerated in all but one lacrimal sac, in which the stent was misplaced. At three and six months after stent placement, stent wires were not encased by epithelium, but at nine months, and one, two and three years after placement, six of the 12 stents had become encased in a proliferation of this where the stent wires contacted the lacrimal sac wall. In no lacrimal system in which stent placement had been successful was migration, stenosis or obstruction of the lacrimal system observed. One misplaced stent caused obstruction of the lacrimal sac, however . In 11 of 12 case (92%), fluoroscopic placement of an expandable metallic stent in the canine lacrimal sac was successful: in 6 of 8 cases (75%), the stent wires became encased by a proliferation of mucosa, but during long-term follow-up of 9 months to 3 years, no obstruction was observed. (author). 20 refs., 1 tab., 5 figs

A case of rectovagino-vesical fistula due to radiation therapy for uterine cancer treated with covered expandable metallic stent

Energy Technology Data Exchange (ETDEWEB)

Ohtsukasa, Shunroh; Okabe, Satoshi; Tanami, Hideaki [Tokyo Medical and Dental Univ. (Japan). School of Medicine] (and others)

2002-04-01

A 65-year-old woman had received a panhysterectomy and radiation therapy for a uterine cancer in 1974 and underwent a drainage operation for a peritonitis due to rupture of the bladder associated with radiation cystitis in 1983. A rectovesical fistula was revealed and partial resection of the bladder and rectum was performed in 1996. In 1998, rectovesical fistula recurred and symptom of fecaluria and contact-type dermatitis at perineal region subsequently worsened. In February, 2000, colonoscopy and gastrograffin-enema revealed a giant recto-vagino-vesical fistula. Although we recommended ileostomy, the patient refused our offer. She gave informed consent to our proposal about the insertion of a covered expandable metallic stent (EMS) into the rectum to treat for fecaluria. After insertion of a covered EMS, fecaluria and contact-type dermatitis at perineal region subsequently improved. Three months later, fecaluria appeared again. Finally, seven months later, severe inflammation occurred at perineal and pubic region because of migration of the covered EMS into the bladder, then we removed the covered EMS and performed ileostomy. It is difficult to use the covered EMS treatment for benign rectovesical or rectovaginal fistula for a long term. (author)

Self-Expandable Metallic Stent Placement in Malignant Gastric Outlet Obstruction

Science.gov (United States)

Ye, Bing-Wei; Lee, Kuei-Chuan; Hsieh, Yun-Cheng; Li, Chung-Pin; Chao, Yee; Hou, Ming-Chih; Lin, Han-Chieh

2015-01-01

Abstract Malignant gastric outlet obstruction is a late complication of intraabdominal malignancy. Self-expandable metallic stent placement has been a safe palliative treatment to relieve obstructive symptoms. We aimed to assess the efficacy and safety of metallic stents in our patients and analyzed the clinical outcome of different brands. Seventy-one patients with inoperable gastric outlet obstruction receiving WallFlex enteral stents (WallFlex group) or Bonastents (Bonastent group) since April 2010 were analyzed retrospectively. The overall technical and clinical success rates of stent placement were 100% and 93%, respectively. The baseline characteristics and clinical outcomes including procedure-related complications, restenosis, and reintervention rates were comparable between the 2 groups. However, the Bonastent group had a higher rate of stent fracture than the WallFlex group (13.3% vs 0%, P = 0.03). The mean duration of overall stent patency was 132.7 days. The mean duration of survival was 181.9 days. Resumption of regular diet or low residual diet at day 7 after stent insertion predicted stent patency (hazard ratio [HR]: 0.28, P = 0.01). Cancer with gastric origin (HR: 0.25, P = 0.045) and poststent chemotherapy (HR: 0.38, P = 0.006) predicted lower mortality; however, peritoneal carcinomatosis (HR: 3.09, P = 0.04) correlated with higher mortality. Metallic stent placement is a safe and effective method for relieving gastric outlet obstruction. Except higher rate of stent fracture in the Bonastent group, there is no significant difference in clinical outcomes between the Bonastent group and the WallFlex group. PMID:26200641

Stent migration following endoscopic suture fixation of esophageal self-expandable metal stents: a systematic review and meta-analysis.

Science.gov (United States)

Law, Ryan; Prabhu, Anoop; Fujii-Lau, Larissa; Shannon, Carol; Singh, Siddharth

2018-02-01

Covered self-expandable metal stents (SEMS) are utilized for the management of benign and malignant esophageal conditions; however, covered SEMS are prone to migration. Endoscopic suture fixation may mitigate the migration risk of covered esophageal SEMS. Hence, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of endoscopic suture fixation for covered esophageal SEMS. Following PRISMA guidelines, we performed a systematic review from 2011 to 2016 to identify studies (case control/case series) reporting the technical success and migration rate of covered esophageal SEMS following endoscopic suture fixation. We searched multiple electronic databases and conference proceedings. We calculated pooled rates (and 95% confidence intervals [CI]) of technical success and stent migration using a random effects model. We identified 14 studies (212 patients) describing covered esophageal SEMS placement with endoscopic suture fixation. When reported, SEMS indications included leak/fistula (n = 75), stricture (n = 65), perforation (n = 10), and achalasia (n = 4). The pooled technical success rate was 96.7% (95% CI 92.3-98.6), without heterogeneity (I 2  = 0%). We identified 29 SEMS migrations at rate of 15.9% (95% CI 11.4-21.6), without heterogeneity (I 2  = 0%). Publication bias was observed, and using the trim-and-fill method, a more conservative estimate for stent migration was 17.0%. Suture-related adverse events were estimated to occur in 3.7% (95% CI 1.6-8.2) of cases. Endoscopic suture fixation of covered esophageal SEMS appears to reduce stent migration when compared to published rates of non-anchored SEMS. However, SEMS migration still occurs in approximately 1 out of 6 cases despite excellent immediate technical success and low risk of suture-related adverse events.

Palliative metallic stent placement for managing esophageal cancer of the aging

International Nuclear Information System (INIS)

Li Qnqi; Yin Huabin; Yue Wei; Ji Chengzhou; Yang Yufeng

2000-01-01

Objective: To evaluate the effectiveness of self-expanding metallic stent in the treatment of the old patients with malignant esophageal stricture. Methods: 32 old patients with malignant esophageal stricture were treated with covered self-expandable metallic stents, 32 stents were placed by X-TV guiding, without pre-dilatation of the stenosis by balloon catheter. Results: All 32 stents were successfully placed, the successful rate was 100%. All of the patients obtained the improvement of the food intake ability. No fatal stent-related complications occurred. The average survival time was 6.5 months. Conclusions: The covered self-expandable metallic stent is effective in the palliative management of malignant esophageal stricture of the aging

Efficacy of Self-Expandable Metallic Stent Inserted for Refractory Hemorrhage of Duodenal Cancer

Directory of Open Access Journals (Sweden)

Takashi Orii

2016-05-01

Full Text Available Because of advances in the technology of gastrointestinal endoscopy and improvements in the quality of stents, it has become routine to place a stent as palliative therapy for malignant gastrointestinal obstruction. On the other hand, stent placement for malignant gastrointestinal hemorrhage has scarcely been reported, although it may be performed for hemorrhage of the esophageal varicose vein. We recently experienced a patient with refractory hemorrhage from an unresectable duodenal cancer who underwent placement of a self-expandable metallic stent (SEMS and thereafter had no recurrence of the hemorrhage. A 46-year-old man underwent laparotomy to radically resect a cancer in the third portion of the duodenum, which invaded widely to the superior mesenteric vein and its branches and was considered unresectable. After stomach-partitioning gastrojejunostomy was performed, chemotherapy was initiated according to the regimen of chemotherapy of far advanced gastric cancer. One year and 4 months after induction of chemotherapy, gastrointestinal hemorrhage occurred. Upper gastrointestinal endoscopy revealed the hemorrhage oozing from the duodenal cancer, and endoscopic hemostasis, such as injection of hypertonic saline epinephrine and argon plasma coagulation, was unsuccessful. Twenty days after emergence of the hemorrhage, an endoscopic covered SEMS was placed with confirmation by fluoroscopy. Immediately after placement of the stent, the tarry stool stopped and the anemia ceased to progress. The recurrence of the hemorrhage has not been confirmed without migration of the stent. SEMS is an effective hemostatic procedure for malignant refractory hemorrhage.

Partially covered versus uncovered self-expandable nitinol stents with anti-migration properties for the palliation of malignant distal biliary obstruction: A randomized controlled trial.

Science.gov (United States)

Yang, Min Jae; Kim, Jin Hong; Yoo, Byung Moo; Hwang, Jae Chul; Yoo, Jun Hwan; Lee, Ki Seong; Kang, Joon Koo; Kim, Soon Sun; Lim, Sun Gyo; Shin, Sung Jae; Cheong, Jae Youn; Lee, Kee Myung; Lee, Kwang Jae; Cho, Sung Won

2015-01-01

Covered self-expandable metal stents (SEMSs) are increasingly used as alternatives to uncovered SEMSs for the palliation of inoperable malignant distal biliary obstruction to counteract tumor ingrowth. We aimed to compare the outcomes of partially covered and uncovered SEMSs with identical mesh structures and anti-migration properties, such as low axial force and flared ends. One hundred and three patients who were diagnosed with inoperable malignant distal biliary obstruction between January 2006 and August 2013 were randomly assigned to either the partially covered (n = 51) or uncovered (n = 52) SEMS group. There were no significant differences in the cumulative stent patency, overall patient survival, stent dysfunction-free survival and overall adverse events, including pancreatitis and cholecystitis, between the two groups. Compared to the uncovered group, stent migration (5.9% vs. 0%, p = 0.118) and tumor overgrowth (7.8% vs. 1.9%, p = 0.205) were non-significantly more frequent in the partially covered group, whereas tumor ingrowth showed a significantly higher incidence in the uncovered group (5.9% vs. 19.2%, p = 0.041). Stent migration in the partially covered group occurred only in patients with short stenosis of the utmost distal bile duct (two in ampullary cancer, one in bile duct cancer), and did not occur in any patients with pancreatic cancer. For the palliation of malignant distal biliary obstruction, endoscopic placement of partially covered SEMSs with anti-migration designs and identical mesh structures to uncovered SEMSs failed to prolong cumulative stent patency or reduce stent migration.

A Multicenter, Prospective Study of a New Fully Covered Expandable Metal Biliary Stent for the Palliative Treatment of Malignant Bile Duct Obstruction

Directory of Open Access Journals (Sweden)

Bret T. Petersen

2013-01-01

Full Text Available Background and Study Aims. Endoscopic placement of self-expanding metal stents (SEMSs is indicated for palliation of inoperable malignant biliary obstruction. A fully covered biliary SEMS (WallFlex Biliary RX Boston Scientific, Natick, USA was assessed for palliation of extrahepatic malignant biliary obstruction. Patients and Methods. 58 patients were included in this prospective, multicenter series conducted under an FDA-approved IDE. Main outcome measurements included (1 absence of stent occlusion within six months or until death, whichever occurred first and (2 technical success, need for reintervention, bilirubin levels, stent patency, time to stent occlusion, and adverse events. Results. Technical success was achieved in 98% (57/58, with demonstrated acute removability in two patients. Adequate clinical palliation until completion of followup was achievedin 98% (54/55 of evaluable patients, with 1 reintervention due to stent obstruction after 142 days. Mean total bilirubin decreased from 8.9 mg/dL to 1.2 mg/dL at 1 month. Device-related adverse events were limited and included 2 cases of cholecystitis. One stent migrated following radiation therapy. Conclusions. The WallFlex Biliary fully covered stent yielded technically successful placement with uncomplicated acute removal where required, appropriate reduction in bilirubin levels, and low rates of stent migration and occlusion. This SEMS allows successful palliation of malignant extrahepatic biliary obstruction.

Novel characteristics of traction force in biliary self-expandable metallic stents.

Science.gov (United States)

Hori, Yasuki; Hayashi, Kazuki; Yoshida, Michihiro; Naitoh, Itaru; Ban, Tesshin; Miyabe, Katsuyuki; Kondo, Hiromu; Nishi, Yuji; Umemura, Shuichiro; Fujita, Yasuaki; Natsume, Makoto; Kato, Akihisa; Ohara, Hirotaka; Joh, Takashi

2017-05-01

In recent years, knowledge concerning the mechanical properties of self-expandable metallic stents (SEMS) has increased. In a previous study, we defined traction force and traction momentum and reported that these characteristics are important for optimal stent deployment. However, traction force and traction momentum were represented as relative values and were not evaluated in various conditions. The purpose of the present study was to measure traction force in various situations assumed during SEMS placement. Traction force and traction momentum were measured in non-stricture, stricture, and angled stricture models using in-house equipment. Stricture and angled stricture models had significantly higher traction force and traction momentum than those of the non-stricture model (stricture vs non-stricture: traction force, 7.2 N vs 1.4 N, P stent influenced the traction force. Clinicians should be aware of the transition of the traction force and should schedule X-ray imaging during SEMS placement. © 2017 Japan Gastroenterological Endoscopy Society.

Y-shaped bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction: data from a referral center for palliative care.

Science.gov (United States)

Di Mitri, R; Mocciaro, F

2014-01-01

Malignant hilar strictures are a clinical challenge because of the current therapeutic approach and the poor prognosis. In recent years, self-expandable metallic stents have proven more effective than plastic stents for palliation of malignant hilar strictures, with the bilateral stent-in-stent technique registering a high success rate. We report our experience with Y-shaped endoscopic self-expandable metallic stents placement for treatment of advanced malignant hilar strictures. From April 2009 to August 2012, we prospectively collected data on patients treated with Y-shaped SEMS placement for advanced malignant hilar carcinoma. Data on technical success, clinical success, and complications were collected. Twenty patients (9 males) were treated (mean age 64.2 ± 15.3 years). The grade of malignant hilar strictures according to the Bismuth classification was II in 5 patients (25%), IIIa in 1 (5%), and IV in 14 (70%). The mean bilirubin level was 14.7 ± 4.9 mg/dL. Technical success was achieved in all patients, with a significant reduction in bilirubin levels (2.9 ± 1.7 mg/dL). One patient experienced cholangitis as early complication, while in 2 patients stent ingrowth was observed. No stents migration was recorded. There was no procedure-related mortality. At the end of the follow-up (7.1 ± 3.1 months), 13 of the 20 patients (65%) had died. Our experience confirms endoscopic bilateral self-expandable metallic stents placement with stent-in-stent technique (Y-shaped configuration) as a feasible, effective, and safe procedure for palliation of unresectable malignant hilar strictures.

Long-Term Outcomes of Double-Layered Polytetrafluoroethylene Membrane-Covered Self-Expandable Segmental Metallic Stents (Uventa) in Patients with Chronic Ureteral Obstructions: Is It Really Safe?

Science.gov (United States)

Kim, Myong; Hong, Bumsik; Park, Hyung Keun

2016-12-01

To evaluate the long-term clinical efficacy and safety of double-layered polytetrafluoroethylene membrane-covered self-expandable segmental metallic stents (Uventa) in patients with chronic ureteral obstruction. In a retrospective study, a total of 50 ureter units (44 patients) with chronic obstructions were included from July 2010 to May 2015. Indications for Uventa placement were primary stenting for malignant ureteral obstruction, failed conventional polymeric Double-J stent (PS), or percutaneous nephrostomy (PCN) technique, with comorbidities or fears limiting PS/PCN changes, or with irritation or pain due to PS/PCN. Patients underwent Uventa stent placement using the antegrade or retrograde approach. There were no immediate procedure-related complications, and all stents were placed in the proper sites. During the median follow-up of 30.9 (interquartile range [IQR], 8.1-49.0) months, the primary (no obstruction and no additional intervention) and overall success (no obstruction and no additional intervention except supplementary Uventa) was 30.0% and 34.0%, respectively. Moreover, 14 of 50 ureter units (28.0%) experienced major complications (≥Clavien-Dindo class IIIb), such as ureteroarterial fistula (three cases, 6.0%), ureteroenteric fistula (three, 6.0%), ureterovaginal fistula (one, 2.0%), ureter perforation (one, 2.0%), uncontrollable bleeding (one, 2.0%), and complete obstruction (five, 10.0%). On univariate analysis, major complications were associated with female (odds ratio [OR] = 6.000), cervical cancer (OR = 4.667), ureteral stricture length (≥6.0 cm, OR = 4.583), and placement duration (≥24.0 months, OR = 20.429; all p stent demonstrated poor treatment outcomes with frequent major complications in patients with chronic ureteral obstructions.

Palliative self-expandable metal stents for acute malignant colorectal obstruction: clinical outcomes and risk factors for complications.

Science.gov (United States)

Han, Jae Pil; Hong, Su Jin; Kim, Shin Hee; Choi, Jong Hyo; Jung, Hee Jae; Cho, Youn Hee; Ko, Bong Min; Lee, Moon Sung

2014-08-01

Self-expandable metal stents (SEMSs) have been used as palliative treatment or bridge to surgery for obstructions caused by colorectal cancer (CRC). We assessed the long-term outcomes of palliative SEMSs and evaluated the risk factors influencing complications. One hundred and seventy-five patients underwent SEMS placement for acute malignant colorectal obstruction. Of the 72 patients who underwent palliative treatment for primary CRC, 30 patients received chemotherapy (CT) for primary cancer (CT group) and 42 underwent best supportive treatment (BST) without CT (BST group). There was a significant difference in late migration between the CT group and the BST group (20.0% in CT group, 2.4% in BST group, p = 0.018). Response to CT influenced the rate of late obstruction (0% in disease control, 35.7% in disease progression, p = 0.014). However, late obstruction was not associated with stent properties, such as diameter or type (≤22 mm vs. >22 mm, 13.5% vs. 14.3%, p = 1.00; uncovered stent vs. covered stent, 15.5% vs. 7.1%, p = 0.675) and migration (≤22 mm vs. >22 mm, 16.2% vs. 2.9%, p = 0.108; uncovered stent vs. covered stent, 8.6% vs. 14.3%, p = 0.615) in palliative SEMS. The administration of CT increases the rate of stent migration, and disease control by CT can reduce the risk of obstruction by maintaining the luminal patency of palliative SEMSs.

Y-Shaped Bilateral Self-Expandable Metallic Stent Placement for Malignant Hilar Biliary Obstruction: Data from a Referral Center for Palliative Care

Directory of Open Access Journals (Sweden)

R. Di Mitri

2014-01-01

Full Text Available Background and Aim. Malignant hilar strictures are a clinical challenge because of the current therapeutic approach and the poor prognosis. In recent years, self-expandable metallic stents have proven more effective than plastic stents for palliation of malignant hilar strictures, with the bilateral stent-in-stent technique registering a high success rate. We report our experience with Y-shaped endoscopic self-expandable metallic stents placement for treatment of advanced malignant hilar strictures. Methods. From April 2009 to August 2012, we prospectively collected data on patients treated with Y-shaped SEMS placement for advanced malignant hilar carcinoma. Data on technical success, clinical success, and complications were collected. Results. Twenty patients (9 males were treated (mean age 64.2 ± 15.3 years. The grade of malignant hilar strictures according to the Bismuth classification was II in 5 patients (25%, IIIa in 1 (5%, and IV in 14 (70%. The mean bilirubin level was 14.7 ± 4.9 mg/dL. Technical success was achieved in all patients, with a significant reduction in bilirubin levels (2.9 ± 1.7 mg/dL. One patient experienced cholangitis as early complication, while in 2 patients stent ingrowth was observed. No stents migration was recorded. There was no procedure-related mortality. At the end of the follow-up (7.1 ± 3.1 months, 13 of the 20 patients (65% had died. Conclusions. Our experience confirms endoscopic bilateral self-expandable metallic stents placement with stent-in-stent technique (Y-shaped configuration as a feasible, effective, and safe procedure for palliation of unresectable malignant hilar strictures.

Implantation of modified Y-shaped self-expandable stent for the treatment of stenosis of gastroenteric stoma: preliminary results in five cases

International Nuclear Information System (INIS)

Wu Gang; Si Jiangtao; Han Xinwei; Jiao Dechao; Ding Pengxu; Fu Mingti; Li Zhen; Ma Ji

2010-01-01

Objective To investigate the feasibility and therapeutic effect of stenting therapy by using modified Y-shaped self-expandable metal stent for the stenosis of gastroenteric stoma. Methods: According to the particular anatomic structures and the pathological features of the narrowed gastroenteric stoma,the authors designed a modified Y-shaped self-expandable metal stent. Under the fluoroscopic guidance, implantation of modified Y-shaped self-expandable metal stent was performed in 5 patients with narrowed gastroenteric stoma. The technical safety and the clinical results were evaluated. Results: The modified Y-shaped self-expandable metal stent was successfully implanted with one procedure in all five patients. After the implantation the symptoms such as nausea, vomiting, abdominal distension were promptly relieved, and the patients' living quality was markedly improved. Conclusion: The stenting therapy with modified Y-shaped self-expandable metal stent can rapidly relieve the stenosis of gastroenteric stoma once for all. The technique is feasible and the short-term effect is reliable, therefore, it is worth popularizing this therapy in clinical practice. (authors)

Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

1991-05-15

To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction.

Expandable metallic stent: experimental and clinical experience in tracheobronchial tree

International Nuclear Information System (INIS)

Song, Ho Young; Lee, Sang Young; Chung, Jin Young; Han, Young Min; Kim, Jong Soo; Choi, Ki Chul; Hong, Ki Whan; Rhee, Yang Kun

1991-01-01

To maintain or reestablish an adequate airway in a patient with tracheobronchial narrowing coming from various causes, we constructed self-expanding metallic stents the same way Gianturco did, using them in 2 patients after an experimental study with rabbits. Twenty stents (10mm in diameter fully expanded and 20mm in length) were introduced into the trachea or bronchi of 10 Newzealand rabbits (weight, 2.5-3.0kg) through a 8.5 French Teflon sheath. No difficulties were encountered in the placement of the stents. At follow-up (4-12 weeks), no stent showed migration. Three rabbits died of pneumonia or bronchial perforation. Histologically, mucosal inflammation was noted at the sites of stent placement, and stent wires were covered by proliferated epithelium with intact cilia. During the last 4 months, 2 stents were used in 2 patients, one in a patient with endobronchial tuberculosis (3.0cm in length and 1.0cm in diameter fully expanded) and the other (3.0cm in length and 1.5cm in diameter) in a patient with a subglottic mass. In both patients the stents were successfully placed. Just after the placement of the stents dyspnea subsided in both patients, and there was no mortality or morbidity. These stents seem to be effective in the treatment of tracheobronchial stenosis, tracheomalacia, and airway collapse following tracheal reconstruction

Expandable esophageal metallic stents coating with silicone rubber: An experimental study in rabbits

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young; Han, Young Min; Son, Myung Hee; Kim, Jong Soo; Choi, Ki Chul; Kuh, Ja Hong; Chae, Soo Wan [Chonbuk National University Medical School, Chonju (Korea, Republic of); Kim, Hak Nam [Chungju Lee Rha Hospital, Chungju (Korea, Republic of)

1990-10-15

To determine the effect of the expandable esophageal metallic stents on the esophagus, we constructed an expandable metallic stent. It was stainless steel wire formed in a zig-zag pattern in fully expanded diameter. Twenty stents were introduced in the normal esophagus through a 8.5 French-teflon sheath in 10 rabbits for 1 week to 12 weeks. Three out of the 20 stents migrated slightly. At 1 week after the placement of the stent, the mucosa partly revealed pressure necrosis and some regeneration, the muscle layer below the stent wires found compressed and thinned. At 8 weeks, the mucosa showed complete regeneration, and the stent wires were found covered by fibrous tissue.

Covered Balloon-Expanding Stents in Airway Stenosis.

Science.gov (United States)

Majid, Adnan; Kheir, Fayez; Chung, Jey; Alape, Daniel; Husta, Bryan; Oh, Scott; Folch, Erik

2017-04-01

The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (Pstent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.

Comparison between gastrostomy feeding and self-expandable metal stent insertion for patients with esophageal cancer and dysphagia.

Science.gov (United States)

Min, Yang Won; Jang, Eun Young; Jung, Ji Hey; Lee, Hyuk; Min, Byung-Hoon; Lee, Jun Haeng; Rhee, Poong-Lyul; Kim, Jae J

2017-01-01

Self-expandable metal stent (SEMS) insertion and percutaneous gastrostomy (PG) feeding are commonly used for patients with esophageal cancer and dysphagia. This study aimed to compare outcomes between SEMS insertion and PG feeding for them. We retrospectively analyzed 308 patients with esophageal cancer who underwent fully covered SEMS insertion (stent group) or PG (gastrostomy group) for dysphagia due to tumor. Patients with other causes of dysphagia, such as radiation-induced or postoperative stricture, were excluded from the study. Clinical outcomes were compared between the two groups, including overall survival and need for additional intervention and postprocedural nutritional status. At baseline, the stent group (n = 169) had more stage IV patients, less cervical cancers, and received radiotherapy and esophagectomy less often than the gastrostomy group (n = 64). The Kaplan-Meier curves showed higher overall survival in the gastrostomy group than in the stent group. Multivariate analysis revealed that PG was associated with better survival compared with SEMS insertion (hazard ratio 0.541, 95% confidence interval 0.346-0.848, p = 0.007). In addition, the gastrostomy group needed additional intervention less often (3.1% vs. 21.9%, p esophageal cancer and dysphagia. Stabilized nutritional status by PG may play a role in improving patient survival.

Malignant biliary obstruction: percutaneous use of self-expandable stents

NARCIS (Netherlands)

Laméris, J. S.; Stoker, J.; Nijs, H. G.; Zonderland, H. M.; Terpstra, O. T.; van Blankenstein, M.; Schütte, H. E.

1991-01-01

A total of 83 self-expandable metallic stents were placed percutaneously in 69 patients for palliation of malignant biliary obstruction. Stent diameter was 1 cm; length, 3.5-10.5 cm. Of the 41 patients with common bile duct obstruction, 27 died 0.2-12 months (median, 3.2 months) after stent

Self-expandable metal stents for malignant esophageal obstruction: a comparative study between extrinsic and intrinsic compression.

Science.gov (United States)

Rhee, K; Kim, J-H; Jung, D H; Han, J W; Lee, Y C; Lee, S K; Shin, S K; Park, J C; Chung, H S; Park, J J; Youn, Y H; Park, H

2016-04-01

Self-expandable metal stents (SEMSs) are effective for malignant esophageal obstruction, but usefulness of SEMSs in extrinsic lesions is yet to be elucidated. This study is aimed at evaluating the clinical usefulness of SEMSs in the extrinsic compression compared with intrinsic. A retrospective review was conducted for 105 patients (intrinsic, 85; extrinsic, 20) with malignant esophageal obstruction who underwent endoscopic SEMSs placement. Technical and clinical success rates were evaluated and clinical outcomes were compared between extrinsic and intrinsic group. Extrinsic group was mostly pulmonary origin. Overall technical and clinical success rate was 100% and 91%, respectively, without immediate complications. Extrinsic and intrinsic group did not differ significantly in clinical success rate. The median stent patency time was 131.3 ± 85.8 days in intrinsic group while that of extrinsic was 54.6 ± 45.1 due to shorter survival after stent insertion. The 4-, 8-, and 12-week patency rates were 90.5%, 78.8%, and 64.9% respectively in intrinsic group, while stents of extrinsic group remained patent until death. Uncovered, fully covered, and double-layered stent were used evenly and the types did not influence patency in both groups. In conclusion, esophageal SEMSs can safely and effectively be used for malignant extrinsic compression as well as intrinsic. © 2015 International Society for Diseases of the Esophagus.

A systematic review and meta-analysis of randomized trials and prospective studies comparing covered and bare self-expandable metal stents for the treatment of malignant obstruction in the digestive tract.

Science.gov (United States)

Yang, Zhiping; Wu, Qiong; Wang, Fang; Ye, Xiaofei; Qi, Xingshun; Fan, Daiming

2013-01-01

Self-expandable metal stents (SEMS) are widely used for the palliative treatment of malignant gastrointestinal obstruction. Our aim was to evaluate the evidence comparing covered and bare SEMS in the digestive tract using meta-analytical techniques. A literature search was performed using PubMed, Cochrane Library, and Embase databases for comparative studies assessing the two types of stents. The primary outcomes of interest were stent patency and patient survival; second outcomes included technical success, clinical success, tumor ingrowth, tumor overgrowth, and stent migration. A random-effects model was conducted. Pooled analysis was done separately based on the different segments of the digestive tract. Eleven studies (8 randomized controlled trials and 3 prospective cohort studies) including a total of 1376 patients were identified. Covered SEMS were equivalent to bare SEMS in terms of technical success, clinical success, stent patency (gastroduodenal obstruction: HR =0.87, 95% CI 0.53-1.42; colorectal obstruction: HR =0.89, 95% CI 0.18-4.45; biliary obstruction: HR =0.73, 95% CI 0.41-1.32) and survival rates (esophageal obstruction: HR =1.80, 95% CI 0.73-4.44; gastroduodenal obstruction: HR =0.83, 95% CI 0.55-1.26; biliary obstruction: HR =0.99, 95% CI 0.77-1.28), although bare stents were more prone to tumor ingrowth (esophageal obstruction: RR =0.10, 95% CI 0.01-0.77; gastroduodenal obstruction: RR =0.12, 95% CI 0.03-0.55; colorectal obstruction: RR =0.21, 95% CI 0.06-0.70; biliary obstruction: RR =0.21, 95% CI 0.06-0.69), whereas covered stents had the higher risk of stent migration (gastroduodenal obstruction: RR =5.01, 95% CI 1.53-16.43; colorectal obstruction: RR =11.70, 95% CI 2.84-48.27; biliary obstruction: RR =8.11, 95% CI 1.47-44.76) and tumor overgrowth (biliary obstruction: RR =2.03, 95% CI 1.08-3.78). Both covered and bare SEMS are comparable in efficacy for the palliative treatment of malignant obstruction in the digestive tract. Each type of

Palliative of malignant esophageal stenoses and their complications using self-expandable stets

International Nuclear Information System (INIS)

Manova, G.; Totev, M.; Kamburov, V.; Tcherveniakov, A.; Spaskov, S.

2006-01-01

Full text: One of the best modalities to improve quality of live of the patients with malignant dysphagia, who are bad candidates for surgery, is stenting with self-expandable metal stents. In critically ill patients it remains the last therapeutic possibility. The aim of the study is to evaluate the combined endoscopic- radiological approach in treatment of the dysphagia with malignant origin using self expandable metal stents in unsuitable for surgery patients. Between 10.2002 and 04.2006 we studied 42 consecutive patients (36 males and 6 females), mean age 63.3 (SD=8.28) years with advanced (range 3, 4 and 5) dysphagia. All patients had metastatic disease, four of them were critically ill (aspiration pneumonia due to malignant fistula). The manipulation was performed by one endoscopist, one radiologist and one assistant with combined endoscopically- radiological approach. After obtaining informed consent and sedating the patient, we insert a firm canula trough the scope and instill iodine contrast. We mark the edges of the stenosis on the skin, choose a stent with proper length, place a stiff guide wire via the endoscopic channel and remove the scope. We used covered self-expandable metal stents FerX-ELLA (Hradec Kralove, Czechs Republic) with antireflux valves. We insert the delivery system over the wire, position the prosthesis under x-ray control according to the skin marks and release the stent. In 34 cases the reason for dysphagia was primary tumor (7 - middle third, 22 - distal third of the esophagus, five - cardia). In five cases the dysphagia was due to recurrence after gastrooesophagoplasty. Another five patients presented with malignant esophageal-respiratory fistula. In 52% the histology of the tumor revealed adenocarcinoma, in 40% - squamocellular and in 8% adenosquamous carcinoma. In tree cases there was extrinsic compression due to mediastinal mass (two bronchial carcinoma, one lymphoma). Technically successful one-step manipulation was achieved in

Short-term results of self-expanding metal stents for acute malignant large bowel obstruction

DEFF Research Database (Denmark)

Kobborg, M; Broholm, M; Frostberg, E

2017-01-01

AIM: Self-expanding metal stents (SEMSs) can be used as a palliative treatment or to initially decompress colon prior to definitive surgery (as a so-called 'bridge to surgery'). The purpose of this study was to investigate the efficacy and safety of SEMS used as palliation and bridge to surgery...... for malignant large bowel obstruction. METHOD: A multicentre retrospective study was conducted from January 2010 to December 2013 to identify patients undergoing stent placement for acute large bowel obstruction. Patients were included from four Danish colorectal centres. Outcomes identified included clinical...... success, 30-day mortality, stent related complications and surgery related complications. Furthermore, we analysed for predictive factors for successful stenting. Clinical success was defined as relief of obstructive symptoms, without the need of other additional surgical interventions during the hospital...

Self-expandable metalic endotracheal stent

International Nuclear Information System (INIS)

Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae

1993-01-01

Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author)

Self-expandable metalic endotracheal stent

Energy Technology Data Exchange (ETDEWEB)

Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1993-01-01

Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author).

Palliation of Malignant Upper Gastrointestinal Obstruction with Self-Expandable Metal Stent

Energy Technology Data Exchange (ETDEWEB)

Morikawa, Soichiro; Suzuki, Azumi; Nakase, Kojiro; Yasuda, Kenjiro [Kyoto Second Red Cross Hospital, Kyoto (Japan)

2012-02-15

To assess the technical success, ability to eat, complications and clinical outcomes of patients with self-expandable metal stent (SEMS) placed for malignant upper gastrointestinal (GI) obstruction. Data was collected retrospectively on patients who underwent SEMS placement for palliation of malignant upper GI obstruction by reviewing hospital charts from June 1998 to May 2011. Main outcome measurements were technical success, gastric outlet obstruction scoring system (GOOSS) score before and after treatment, complications, and survival. A total of 82 patients underwent SEMS placement with malignant upper GI obstruction. The initial SEMS placement was successful in 77 patients (93.9%). The mean GOOSS score was 0.56 before stenting and 1.92 (p < 0.001) after treatment. Complications arose in 12 patients (14.6%): stent migration in 1 patient (1.2%), perforation in 1 (1.2%), and obstruction of stent due to tumor ingrowth in 10 (12.2%). The median survival time after stenting was 52 days (6-445). SEMS placement is an effective and safe treatment for palliation of malignant upper GI obstruction. It provides lasting relief in dysphagia and improves the QOL of patients.

Palliation of Malignant Upper Gastrointestinal Obstruction with Self-Expandable Metal Stent

International Nuclear Information System (INIS)

Morikawa, Soichiro; Suzuki, Azumi; Nakase, Kojiro; Yasuda, Kenjiro

2012-01-01

To assess the technical success, ability to eat, complications and clinical outcomes of patients with self-expandable metal stent (SEMS) placed for malignant upper gastrointestinal (GI) obstruction. Data was collected retrospectively on patients who underwent SEMS placement for palliation of malignant upper GI obstruction by reviewing hospital charts from June 1998 to May 2011. Main outcome measurements were technical success, gastric outlet obstruction scoring system (GOOSS) score before and after treatment, complications, and survival. A total of 82 patients underwent SEMS placement with malignant upper GI obstruction. The initial SEMS placement was successful in 77 patients (93.9%). The mean GOOSS score was 0.56 before stenting and 1.92 (p < 0.001) after treatment. Complications arose in 12 patients (14.6%): stent migration in 1 patient (1.2%), perforation in 1 (1.2%), and obstruction of stent due to tumor ingrowth in 10 (12.2%). The median survival time after stenting was 52 days (6-445). SEMS placement is an effective and safe treatment for palliation of malignant upper GI obstruction. It provides lasting relief in dysphagia and improves the QOL of patients.

Self-expandable metal stent for palliation of malignant dysphagia & quality of life improvement in advanced cancer esophagus: Upper Egypt experience

OpenAIRE

Mohamed Abdelshafy; Mohammed A. Omar; Mohamed Abdel Bary; Mohamed Mostafa Wahaman; Rafaat Abd elaal Bakheet

2017-01-01

Background: In advanced cancer esophagus patients, self-expandable metallic stents (SEMS) are utilized to relieve malignant difficulty in swallowing and improve their quality of the life. Retrospectively, we evaluated the efficacy, feasibility, and outcomes of SEMS in palliation of malignant dysphagia in advanced cancer esophagus and its' complications. Methods: We retrospectively reviewed data of 350 patients with malignant dysphagia due to advanced cancer esophagus from December 2012 to ...

Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul [Chonbuk National University Medical School, Chonju(Korea, Republic of)

1993-11-15

Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size.

Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

International Nuclear Information System (INIS)

Song, Ho Young; Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul

1993-01-01

Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size

Clinical outcomes of self-expandable stent placement for benign esophageal diseases: A pooled analysis of the literature

Science.gov (United States)

van Halsema, Emo E; van Hooft, Jeanin E

2015-01-01

AIM: To analyze the outcomes of self-expandable stent placement for benign esophageal strictures and benign esophageal leaks in the literature. METHODS: The PubMed, Embase and Cochrane databases were searched for relevant articles published between January 2000 and July 2014. Eight prospective studies were identified that analyzed the outcomes of stent placement for refractory benign esophageal strictures. The outcomes of stent placement for benign esophageal leaks, perforations and fistulae were extracted from 20 retrospective studies that were published after the inclusion period of a recent systematic review. Data were pooled and analyzed using descriptive statistics. RESULTS: Fully covered self-expandable metal stents (FC SEMS) (n = 85), biodegradable (BD) stents (n = 77) and self-expandable plastic stents (SEPS) (n = 70) were inserted in 232 patients with refractory benign esophageal strictures. The overall clinical success rate was 24.2% and according to stent type 14.1% for FC SEMS, 32.9% for BD stents and 27.1% for SEPS. Stent migration occurred in 24.6% of cases. The overall complication rate was 31.0%, including major (17.7%) and minor (13.4%) complications. A total of 643 patients were treated with self-expandable stents mainly for postsurgical leaks (64.5%), iatrogenic perforations (19.6%), Boerhaave’s syndrome (7.8%) and fistulae (3.7%). FC SEMS and partially covered SEMS were used in the majority of patients. Successful closure of the defect was achieved in 76.8% of patients and according to etiology in 81.4% for postsurgical leaks, 86.0% for perforations and 64.7% for fistulae. The pooled stent migration rate was 16.5%. Stent-related complications occurred in 13.4% of patients, including major (7.8%) and minor (5.5%) complications. CONCLUSION: The outcomes of stent placement for refractory benign esophageal strictures were poor. However, randomized trials are needed to put this into perspective. The evidence on successful stent placement for benign

Clinical outcomes of self-expandable stent placement for benign esophageal diseases: A pooled analysis of the literature.

Science.gov (United States)

van Halsema, Emo E; van Hooft, Jeanin E

2015-02-16

To analyze the outcomes of self-expandable stent placement for benign esophageal strictures and benign esophageal leaks in the literature. The PubMed, Embase and Cochrane databases were searched for relevant articles published between January 2000 and July 2014. Eight prospective studies were identified that analyzed the outcomes of stent placement for refractory benign esophageal strictures. The outcomes of stent placement for benign esophageal leaks, perforations and fistulae were extracted from 20 retrospective studies that were published after the inclusion period of a recent systematic review. Data were pooled and analyzed using descriptive statistics. Fully covered self-expandable metal stents (FC SEMS) (n = 85), biodegradable (BD) stents (n = 77) and self-expandable plastic stents (SEPS) (n = 70) were inserted in 232 patients with refractory benign esophageal strictures. The overall clinical success rate was 24.2% and according to stent type 14.1% for FC SEMS, 32.9% for BD stents and 27.1% for SEPS. Stent migration occurred in 24.6% of cases. The overall complication rate was 31.0%, including major (17.7%) and minor (13.4%) complications. A total of 643 patients were treated with self-expandable stents mainly for postsurgical leaks (64.5%), iatrogenic perforations (19.6%), Boerhaave's syndrome (7.8%) and fistulae (3.7%). FC SEMS and partially covered SEMS were used in the majority of patients. Successful closure of the defect was achieved in 76.8% of patients and according to etiology in 81.4% for postsurgical leaks, 86.0% for perforations and 64.7% for fistulae. The pooled stent migration rate was 16.5%. Stent-related complications occurred in 13.4% of patients, including major (7.8%) and minor (5.5%) complications. The outcomes of stent placement for refractory benign esophageal strictures were poor. However, randomized trials are needed to put this into perspective. The evidence on successful stent placement for benign esophageal leaks, perforations and

Treatment of Postoperative Leaks of the Upper Gastrointestinal Tract with Colonic Self-Expandable Metal Stents.

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Sousa, Paula; Castanheira, António; Martins, Diana; Pinho, Juliana; Araújo, Ricardo; Cancela, Eugénia; Ministro, Paula; Silva, Américo

2017-07-01

The use of self-expandable metal stents (SEMS) for the treatment of postoperative leaks of the upper gastrointestinal tract is already established. However, there are discrepancies between the relatively small caliber of the esophageal stents available and the postsurgical luminal size, which may determine an inadequate juxtaposition. As colonic stents have a bigger diameter, they might be more adequate. Additionally, stents with a larger diameter might have a lower risk of migration. The aim of this study was to evaluate the efficacy and complications associated with the use of colonic fully covered SEMS (FSEMS) in the treatment of postoperative leaks in critical patients. All patients with postoperative leaks of the upper gastrointestinal tract treated with colonic stents (Hanarostent® CCI) between 2010 and 2013 were retrospectively included. Four patients with postoperative leaks were treated with colonic SEMS. The underlying surgeries were a gastric bypass, an esophagogastrectomy for Boerhaave syndrome, a primary repair of esophagopleural fistula due to Boerhaave syndrome, and an esophagectomy due to esophageal cancer. The leaks were detected on average 17 days after the initial surgery. All patients needed admission to a critical care unit after index surgery. Stent placement was technically feasible in all patients. The median residence time of the stents was 7 weeks, and no complications were verified when they were removed. There were no cases of stent migration. The treatment was successful in all patients, with complete healing of the leaks. The placement of colonic FSEMS seems to be successful and safe in the treatment of postoperative leaks of the upper gastrointestinal tract.

Treatment of Benign Tracheal Stenosis Utilizing Self-Expanding Nitinol Stents

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Sesterhenn, Andreas M.; Wagner, Hans-Joachim; Alfke, Heiko; Werner, Jochen A.; Lippert, Burkard M.

2004-01-01

We assessed the results of self-expanding metallic stent insertion into benign proximal tracheal stenosis in patients not appropriate or unfit for surgical repair. Proximal benign tracheal stenoses had occurred in 11 patients (7 men, 4 women, mean age 68.8 years) after long-time intubation (n = 6), tracheostomy (n = 4), or chondropathia (n = 1). Fourteen self-expanding nitinol stents were placed in the patients under general anesthesia with endoscopical and fluoroscopical guidance. Stent insertion was successful in all cases and led to immediate relief of the morphological and functional airway obstruction. No immediate complications were noted. During the mean follow-up period of 67.5 weeks we observed one recurrent dyspnea 3 months after implantation and granuloma formation at the stent insertion site in another patient. Both complications were successfully treated with additional stent insertion in one case and laser resection of granulomas in the other. Self-expanding nitinol stents should be considered for the treatment of benign proximal tracheal obstruction in selected patients for whom surgical repair is contraindicated

An experimental study on expandable endovascular metallic stents in dogs

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Song, Ho Young; Kim, Hak Nam [Chonbuk National University College of Medicine, Chonju (Korea, Republic of)

1990-12-15

We constructed an expandable endovascular metallic stent in the same way as Giamturco did. Experiments were made to test the ability of these stents to be used in the vessels. A total of 20 stents were passed through a 8.5 French teflon sheath into the normal abdominal aorta. IVC, and iliac artery of four adult dogs for 4 weeks to 12 weeks; 8 stents (10 mm in diameter fully expanded and 20 mm in length) in the abnormal aorta, 7 stents (12 mm/20 mm) in the IVC, and 5 stents (8 mm/20 mm) in the iliac artery. All but two stents showed no migration, and one complete occlusion occurred in right iliac artery of a dog. Histologically, stents wires were covered by neo-intimal proliferation. The side branches of the main vessels remained patent, even stent wires across their orifices. These metallic stents may be used as an endovascular graft material in the nonsurgical treatment of several forms of vascular disease.

Placement of a covered self-expandable nitinol stent for bile duct stricture that caused by ischemic injury after transcatheter arterial chemoembolization in a patient with hepatocellular carcinoma: a case report

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Yoo, Kweon; Seo, Tae Seok; Cha, In Ho; Huh, Sik; Byun, Kwan Soo [Guro Hospital, Korea University College of Medicine, Seoul (Korea, Republic of)

2008-10-15

The authors report here on a case of focal stricture in the common hepatic duct that was caused by ischemic bile duct injury after repeat TACE procedures for hepatocellular carcinoma, and the patient was successfully treated with a covered self-expandable nitinol stent.

Influence of a dexamethasone-eluting covered stent on tissue reaction: an experimental study in a canine bronchial model

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Shin, Ji Hoon; Song, Ho-Young; Choi, Gi Bok; Kim, Tae-Hyung; Suh, Ji-Yeon; Seo, Tae-Seok; Yuk, Soon Hong; Kim, Young-Hwa; Cho, Yong-Mee

2005-01-01

This study was designed to evaluate the feasibility and efficacy of a dexamethasone (DXM)-eluting, covered, self-expanding metallic stent to reduce tissue reaction following stent placement in a canine bronchial model. We placed a DXM-eluting, polyurethane-covered, self-expanding metallic stent (drug stent, DS) and a polyurethane-covered, self-expanding metallic stent (control stent, CS) alternately in each left main bronchus and left lower lobe bronchus in 12 dogs. The stents were 20 mm in diameter and length when fully expanded. The dose of DXM was approximately 36.7 mg in each DS, but was absent in the CS. The dogs were euthanased 1 week (n=4), 2 weeks (n=4) or 4 weeks (n=4) after stent placement. Histologic findings, such as epithelial erosion/ulcer or granulation tissue thickness, were obtained from the mid-portion of the bronchus, where the stent had been placed, and evaluated between DS and CS. There were no procedure-related complications or malpositioning of any of the bronchial stents. Stent migration was detected in one dog just before euthanasia 1 week following stent placement. Stent patency was maintained until euthanasia in all dogs. Epithelial erosion/ulcer (%) was significantly less in the DS (mean±standard deviation, 46.88±23.75) than in the CS (73.75±14.08) (P=0.026) for all time-points. There was a decrease in epithelial erosion/ulcer as the follow-up period increased in both DS and CS. The granulation tissue thickness (mm) was less in DS (2.63±2.05) than in CS (3.49±2.95), although the difference was not significant (P=0.751) for all time-points. There was a tendency toward an increase in granulation tissue thickness and chronic lymphocytic infiltration as the follow-up period increased in both DS and CS. In conclusion, DXM-eluting, covered, self-expanding metallic stent seems to be effective in reducing tissue reaction secondary to stent placement in a canine bronchial model. (orig.)

Influence of a dexamethasone-eluting covered stent on tissue reaction: an experimental study in a canine bronchial model

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Shin, Ji Hoon; Song, Ho-Young; Choi, Gi Bok; Kim, Tae-Hyung; Suh, Ji-Yeon [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, Seoul (Korea); Seo, Tae-Seok [Gachon Medical School, Department of Radiology, Gil Medical Center, Inchon (Korea); Yuk, Soon Hong [Hannam University, Department of Polymer Science and Engineering, College of Engineering, Daejeon (Korea); Kim, Young-Hwa [Soonchunhyang University Chonan Hospital, Department of Radiology, Chonan (Korea); Cho, Yong-Mee [University of Ulsan College of Medicine, Department of Pathology, Asan Medical Center, Seoul (Korea)

2005-06-01

This study was designed to evaluate the feasibility and efficacy of a dexamethasone (DXM)-eluting, covered, self-expanding metallic stent to reduce tissue reaction following stent placement in a canine bronchial model. We placed a DXM-eluting, polyurethane-covered, self-expanding metallic stent (drug stent, DS) and a polyurethane-covered, self-expanding metallic stent (control stent, CS) alternately in each left main bronchus and left lower lobe bronchus in 12 dogs. The stents were 20 mm in diameter and length when fully expanded. The dose of DXM was approximately 36.7 mg in each DS, but was absent in the CS. The dogs were euthanased 1 week (n=4), 2 weeks (n=4) or 4 weeks (n=4) after stent placement. Histologic findings, such as epithelial erosion/ulcer or granulation tissue thickness, were obtained from the mid-portion of the bronchus, where the stent had been placed, and evaluated between DS and CS. There were no procedure-related complications or malpositioning of any of the bronchial stents. Stent migration was detected in one dog just before euthanasia 1 week following stent placement. Stent patency was maintained until euthanasia in all dogs. Epithelial erosion/ulcer (%) was significantly less in the DS (mean{+-}standard deviation, 46.88{+-}23.75) than in the CS (73.75{+-}14.08) (P=0.026) for all time-points. There was a decrease in epithelial erosion/ulcer as the follow-up period increased in both DS and CS. The granulation tissue thickness (mm) was less in DS (2.63{+-}2.05) than in CS (3.49{+-}2.95), although the difference was not significant (P=0.751) for all time-points. There was a tendency toward an increase in granulation tissue thickness and chronic lymphocytic infiltration as the follow-up period increased in both DS and CS. In conclusion, DXM-eluting, covered, self-expanding metallic stent seems to be effective in reducing tissue reaction secondary to stent placement in a canine bronchial model. (orig.)

Outcomes of secondary self-expandable metal stents versus surgery after delayed initial palliative stent failure in malignant colorectal obstruction.

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Yoon, Jin Young; Park, Soo Jung; Hong, Sung Pil; Kim, Tae Il; Kim, Won Ho; Cheon, Jae Hee

2013-01-01

When re-intervention is required due to an occluded first colorectal self-expanding metal stent for malignant colorectal obstruction, serious controversies exist regarding whether to use endoscopic re-stenting or surgery. To compare the clinical outcomes in patients who underwent stent re-insertion versus palliative surgery as a second intervention. A total of 115 patients who received either self-expandable metal stent (SEMS) insertion or palliative surgery for treatment of a second occurrence of malignant colorectal obstruction after the first SEMS placement were retrospectively studied between July 2005 and December 2009. The median overall survival (8.2 vs. 15.5 months) and progression-free survival (4.0 vs. 2.7 months) were not significantly different between the stent and surgery groups (p = 0.895 and 0.650, respectively). The median lumen patency in the stent group was 3.4 months and that in the surgery group was 7.9 months (p = 0.003). The immediate complication rate after second stent insertion was 13.9% and late complication rate was observed in 12 of 79 (15.2%) patients. There was no mortality related to the SEMS procedure. The complication and mortality rates associated with palliative surgery were 3.5% (2/57) and 12.3% (7/57), respectively. Although there is no significant difference in the overall survival between stenting and surgery, a secondary stent insertion had a lower mortality rate despite a shorter duration of temporary colorectal decompression compared to that of palliative surgery.

Use of retrievable self-expanding stent in treating childhood benign oesophageal stricture

International Nuclear Information System (INIS)

Yu Juming; Fan Guoping; Zhong Weixing; Zhu Ming

2007-01-01

Objective: To evaluate the methods and effect of retrievable self-expanding esophageal stent in treating benign esophageal stenosis of children. Methods: The covered retrievable expandable nitinol stents were placed in 10 children with corrosive esophageal stenosis and post-anastomotic stenosis, age ranged from 2 to 12 years, the dysphagia scores were 3, Barium esophagography was taken before the use of retrievable stent. Results: The stents were placed safely in all patients without complications and were successfully removed after all. After the stent placement, all patients could take solid food without dysphagia. During 6 to 12 months follow-up after the stent removal, all children could eat satisfactorily with the dysphagia score as 0. Conclusion: The use of covered retrievable expandable stent is effective and safe in treating childhood benign esophageal stenosis. (authors)

Self-expandable metal stents for malignant gastric outlet obstruction: A pooled analysis of prospective literature.

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van Halsema, Emo E; Rauws, Erik A J; Fockens, Paul; van Hooft, Jeanin E

2015-11-21

To provide an overview of the clinical outcomes of self-expandable metal stent (SEMS) placement for malignant gastric outlet obstruction (MGOO). A systematic literature search was performed in PubMed of the literature published between January 2009 and March 2015. Only prospective studies that reported on the clinical success of stent placement for MGOO were included. The primary endpoint was clinical success, defined according to the definition used in the original article. Data were pooled and analyzed using descriptive statistics. Subgroup analyses were performed for partially covered SEMSs (PCSEMSs) and uncovered SEMSs (UCSEMSs) using Fisher's exact test. A total of 19 studies, including 1281 patients, were included in the final analysis. Gastric (42%) and pancreatic (37%) cancer were the main causes of MGOO. UCSEMSs were used in 76% of patients and PCSEMSs in 24%. The overall pooled technical success rate was 97.3% and the clinical success rate was 85.7%. Stent dysfunction occurred in 19.6% of patients, mainly caused by re-obstruction (12.6%) and stent migration (4.3%), and was comparable between PCSEMSs and UCSEMSs (21.2% vs 19.1%, respectively, P = 0.412). Re-obstruction was more common with UCSEMSs (14.9% vs 5.1%, P stent migration was more frequent after PCSEMS placement (10.9% vs 2.2%, P stent patency ranged from 68 to 307 d in five studies. The median overall survival ranged from 49 to 183 d in 13 studies. The clinical outcomes in this large population showed that enteral stent placement was feasible, effective and safe. Therefore, stent placement is a valid treatment option for the palliation of MGOO.

Outcomes of endoscopically inserted self-expandable metal stents in malignancy according to the type of stent and the site of obstruction.

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Jung, Kyoungwon; Ahn, Ji Yong; Jung, Hwoon-Yong; Cho, Charles J; Na, Hee Kyong; Jung, Kee Wook; Lee, Jeong Hoon; Kim, Do Hoon; Choi, Kee Don; Song, Ho June; Lee, Gin Hyug; Kim, Jin-Ho

2016-09-01

Self-expandable metal stents (SEMSs) can be used for the palliation of malignant obstruction in the upper gastrointestinal tract. This study assessed the feasibility and efficacy of endoscopically inserted SEMSs for the palliation of malignant obstruction in the stomach and duodenum. Between January 2011 and April 2014, 220 patients with gastric or duodenal obstruction due to malignancy underwent endoscopic SEMS insertion at Asan Medical Center. The associations of technical/clinical outcomes and complications with the type of stent and site of obstruction were analyzed. The 220 patients included 125 men (56.8 %) and 95 women (43.2 %); median patient age was 63 years. Fully covered, partially covered, and uncovered SEMSs were inserted into 16, 77, and 120 patients, respectively. Obstructions were located in the gastric outlet, including the duodenal bulb, in 106 patients, and in the duodenal second and third portions in 114 patients. Technical success was achieved in 213 of 220 patients (96.8 %) and clinical success in 184 of 213 (86.4 %). Clinical success rates were similar to the type of stent, but were significantly greater for gastric outlet (95/104, 91.3 %) than for duodenal (89/109, 81.7 %) obstructions (p = 0.039). Stent migration was observed in 20 patients (9.1 %) and stent obstruction in 51 (23.2 %). Rates of stent migration were significantly higher for fully covered (6/16, 37.5 %) than for partially covered (7/77, 9.1 %) and uncovered (7/120, 5.8 %) SEMSs (p stent obstruction were similar for fully covered (2/16, 12.5 %), partially covered (17/77, 22.1 %), and uncovered (32/120, 26.7 %) SEMSs (p = 0.409) and in patients with gastric outlet (26/104, 25.0 %) and duodenal (25/109, 22.9 %) obstruction (p = 0.724). SEMS selection for malignant obstruction of the upper gastrointestinal tract depends on the site of obstruction.

Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts in the treatment of acute malignant colorectal obstruction.

Science.gov (United States)

Kim, Honsoul; Kim, Seung Hyoung; Choi, Sun Young; Lee, Kwang-Hun; Won, Jong Yoon; Lee, Do Yun; Lee, Jong Tae

2008-12-01

To evaluate the technical feasibility and clinical effectiveness of fluoroscopically guided placement of self-expandable metallic stents and stent-grafts for acute malignant colorectal obstruction. Radiologic images and clinical reports of 42 patients (22 men, 20 women; age range, 28-93 years; median age, 65.5 years) who underwent fluoroscopically guided colorectal stent insertion without endoscopic assistance for acute malignant obstruction were reviewed retrospectively. Eighteen patients received bare stents as a bridge to surgery. Twenty-four patients received 27 insertions of either a bare stent (n = 15) or a stent-graft (n = 12) for palliation. The obstruction was located in the rectum (n = 8), sigmoid (n = 17), descending colon (n = 8), splenic flexure (n = 3), and transverse colon (n = 6). Clinical success, defined as more than 50% dilatation of the stent with subsequent symptomatic improvement, was achieved in 41 of the 42 patients (98%). No major procedure-related complications occurred. Minor complications occurred in eight of the 45 procedures (18%). No perioperative mortalities occurred within 1 month after surgery. In the palliative group, the median stent patency was 62 days (range, 0-1,014 days). There was no statistically significant difference in stent patency between the bare stents (range, 0-855 days; median, 68 days) and stent-grafts (range, 1-1,014 days; median, 81 days). Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts for the relief of acute malignant colorectal obstruction was technically feasible without endoscopic assistance-even in lesions proximal to the splenic flexure and transverse colon-and clinically effective in both bridge to surgery and palliative management.

Broncho-vascular fistulas from self-expanding metallic stents: A retrospective case review

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Chirag Choudhary

2013-01-01

Full Text Available To highlight a potentially fatal complication of broncho-vascular fistula arising from the self expanding metallic stent (SEMS placement. We retrospectively analyzed five patients with benign and malignant airway diseases, who developed tracheo/broncho-vascular fistulas following SEMS placement in our tertiary care setting. All patients received either Wallstent or Ultraflex® stent (Boston Scientific, Natick, MA between 1999 and 2007. All patients had received adjunct therapy such as balloon bronchoplasty, laser therapy or electrocautery. Most patients presented with massive hemoptysis. A total of 483 SEMS were placed during this period. SEMS placement can be complicated by Broncho-vascular fistula formation. True incidence and precise time interval between the insertion of stent and onset of this complication is unknown. Additional therapeutic modalities to maintain stent patency may enhance the risk of fistula formation. SEMS should only be used in a select sub-group of patients, after exhaustive evaluation of other treatment options. These cases provide evidence that broncho-vascular fistulas can develop at any time following SEMS placement, suggesting the need for a more cautious approach, especially while using them for a long term management. In benign airway disease, the stent should be removed as soon as healing has taken place.

Evaluation of the short- and long-term effectiveness and safety of fully covered self-expandable metal stents for drainage of pancreatic fluid collections: results of a Spanish nationwide registry.

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Vazquez-Sequeiros, Enrique; Baron, Todd H; Pérez-Miranda, Manuel; Sánchez-Yagüe, Andres; Gornals, Joan; Gonzalez-Huix, Ferran; de la Serna, Carlos; Gonzalez Martin, Juan Angel; Gimeno-Garcia, Antonio Z; Marra-Lopez, Carlos; Castellot, Ana; Alberca, Fernando; Fernandez-Urien, Ignacio; Aparicio, Jose Ramon; Legaz, Maria Luisa; Sendino, Oriol; Loras, Carmen; Subtil, Jose Carlos; Nerin, Juan; Perez-Carreras, Mercedes; Diaz-Tasende, Jose; Perez, Gustavo; Repiso, Alejandro; Vilella, Angels; Dolz, Carlos; Alvarez, Alberto; Rodriguez, Santiago; Esteban, Jose Miguel; Juzgado, Diego; Albillos, Agustin

2016-09-01

Initial reports suggest that fully covered self-expandable metal stents (FCSEMSs) may be better suited for drainage of dense pancreatic fluid collections (PFCs), such as walled-off pancreatic necrosis. The primary aim was to analyze the effectiveness and safety of FCSEMSs for drainage of different types of PFCs in a large cohort. The secondary aim was to investigate which type of FCSEMS is superior. This was a retrospective, noncomparative review of a nationwide database involving all hospitals in Spain performing EUS-guided PFC drainage. From April 2008 to August 2013, all patients undergoing PFC drainage with an FCSEMS were included in a database. The main outcome measurements were technical success, short-term (2 weeks) and long-term (6 months) effectiveness, adverse events, and need for surgery. The study included 211 patients (pseudocyst/walled-off pancreatic necrosis, 53%/47%). The FCSEMSs used were straight biliary (66%) or lumen-apposing (34%). Technical success was achieved in 97% of patients (95% confidence interval [CI], 93%-99%). Short-term- and long-term clinical success was obtained in 94% (95% CI, 89%-97%) and 85% (95% CI, 79%-89%) of patients, respectively. Adverse events occurred in 21% of patients (95% CI, 16%-27%): infection (11%), bleeding (7%), and stent migration and/or perforation (3%). By multivariate analysis, patient age (>58 years) and previous failed drainage were the most important factors associated with negative outcome. An FCSEMS is effective and safe for PFC drainage. Older patients with a history of unsuccessful drainage are more likely to fail EUS-guided drainage. The type of FCSEMS does not seem to influence patient outcome. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Fluoroscopic-guided covered metallic stent placement for gastric outlet obstruction and post-operative gastroenterostomy anastomotic stricture

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Lee, Jeong Min; Han, Young Min; Kim, Chong Soo; Lee, Sang Young; Lee, Soo Teik; Yang, Doo Hyun

2001-07-01

AIM: To evaluate the feasibility and safety of fluoroscopic-guided covered metallic stent placements in providing palliative care for patients with inoperable malignant gastric outlet obstruction. MATERIALS AND METHODS: Under fluoroscopic guidance, placement of self-expandable, covered stents was attempted in 20 patients with inoperable or recurrent gastric cancer (age range 36-79 years). All patients had inoperable gastric outlet obstruction, 13 with native anatomy and seven with post-operative anatomy (gastrointestinal anastomotic sites). All patients had intolerance to oral alimentation and/or vomiting after ingestion. Success was defined both technically and clinically. RESULTS: The placement of the stent was technically successful in 18 patients and failed in two patients (technical success: 90%). The cause of the technical failures was an inability to negotiate the guide wire through the obstruction sites in spite of the use of both fluoroscopic and endoscopic guidance. After stent placement, 15 patients were able to ingest at least liquids and had a markedly decreased incidence of vomiting (clinical success: 75%). During the mean follow-up of 6 weeks, there have been no stent reocclusion and no life-threatening complications except migration of two stents in one patient. CONCLUSION: Fluoroscopically guided covered metallic stent placement appears to be valuable for the palliative treatment of malignant obstruction of gastric outlet and post-operative gastrointestinal anastomoses. Lee, J.M. et al. (2001)

Biliary self-expandable metallic stent using single balloon enteroscopy assisted ERCP: overcoming limitations of current accessories

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Rolando Pinho

2013-10-01

Full Text Available Device assisted enteroscopy (DAE techniques have been recently developed for the diagnosis and treatment of small bowel diseases. These techniques can also be used to perform endoscopic retrograde cholangiopancreatography (ERCP in patients with surgically altered anatomies. The main difficulties with DAE-ERCP are related to type of surgery, to the different dimensions and lack of frontal view of the enteroscope and to the resulting limitations with the use of standard accessories, resulting in the need of dedicated accessory devices. Although most ERCP techniques have been successfully performed with DAE-ERCP, biliary self-expandable metallic stents (SEMS have not yet been used, as dedicated biliary SEMS for the enteroscope are lacking. The authors present a case report showing a new method to place standard biliary trough-the-scope SEMS with DAE-ERCP, using a different technique of stent deployment.

Malignant pyloro-duodenal obstruction: Role of self expandable metallic stents

International Nuclear Information System (INIS)

Qureshi, S.; Ghazanfar, S.; Quraishy, M.S.

2014-01-01

Objective: To determine the outcome of duodenal stenting in palliation of patients with malignant pyloric and duodenal obstruction. Methods: The non-randomised prospective descriptive study was conducted at the Endoscopy Suite, Surgical Unit-IV, Civil Hospital, Karachi, from December 2007 to November 2010. All patients presenting with inoperable ampullary, pancreatic or biliary cancers causing duodenal obstruction and patients with resectable malignancy but unfit for surgery were included. The procedure was carried out by a single expert endoscopist under local or general anaesthaesia as required. Boston Scientific stents of variable sizes were used. Follow-up was done at 1 week, 1 month and 6 months. Data analysis was done using SPSS 15. Results: Over the study period, 159 (60%) males and 6 (40%) females were included in the study. The male-to-female ratio was 2:3. The overall age ranged from 25-80 years with a mean of 52.67+-15.07 years. Primary diagnosis was pyloric carcinoma in 7(46.6%), carcinoma Gallbladder in 4(26.6%), Duodenal carcinoma in 3(20%) and carcinoma head of pancreas in 1(6.6%). Relief of symptoms were seen in 11 (73.3%), while complications were seen in 2 (13.3%). Stents were inserted with technical success in 14 (93%) patients. Clinical success was seen in 11 (73%), with a mean survival of 74.27+-40.7 days (range: 15-180 days). No statistical significance was found when comparing the survival time with age, gender and diagnosis. Conclusion: Use of self-expandable metallic stents for gastroduodenal malignancies appears to be a feasible, safe and effective method, especially in those patients with limited life expectancy. (author)

Comparison between gastrostomy feeding and self-expandable metal stent insertion for patients with esophageal cancer and dysphagia.

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Yang Won Min

Full Text Available Self-expandable metal stent (SEMS insertion and percutaneous gastrostomy (PG feeding are commonly used for patients with esophageal cancer and dysphagia. This study aimed to compare outcomes between SEMS insertion and PG feeding for them.We retrospectively analyzed 308 patients with esophageal cancer who underwent fully covered SEMS insertion (stent group or PG (gastrostomy group for dysphagia due to tumor. Patients with other causes of dysphagia, such as radiation-induced or postoperative stricture, were excluded from the study. Clinical outcomes were compared between the two groups, including overall survival and need for additional intervention and postprocedural nutritional status.At baseline, the stent group (n = 169 had more stage IV patients, less cervical cancers, and received radiotherapy and esophagectomy less often than the gastrostomy group (n = 64. The Kaplan-Meier curves showed higher overall survival in the gastrostomy group than in the stent group. Multivariate analysis revealed that PG was associated with better survival compared with SEMS insertion (hazard ratio 0.541, 95% confidence interval 0.346-0.848, p = 0.007. In addition, the gastrostomy group needed additional intervention less often (3.1% vs. 21.9%, p < 0.001 and experienced less decrease in serum albumin levels (-0.15 ± 0.56 g/dL vs. -0.39 ± 0.58 g/dL, p = 0.011 than the stent group after procedure.Our data suggested that, compared with SEMS insertion, PG is associated with better overall survival in patients with esophageal cancer and dysphagia. Stabilized nutritional status by PG may play a role in improving patient survival.

Management of malignant biliary obstruction: Technical and clinical results using an expanded polytetrafluoroethylene fluorinated ethylene propylene (ePTFE/FEP)-covered metallic stent after 6-year experience

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Fanelli, Fabrizio; Orgera, Gianluigi; Bezzi, Mario; Rossi, Plinio; Allegritti, Massimiliano; Passariello, Roberto [University of Rome, Department of Radiological Sciences, Rome (Italy)

2008-05-15

To evaluate the efficacy and safety of an expanded polytetrafluoroethylene-fluorinated ethylene-propylene (ePTFE/FEP)-covered metallic stent in the management of malignant biliary obstruction. Eighty consecutive patients with malignant common bile duct strictures were treated by placement of 83 covered metallic stents. The stent-graft consists of an inner ePTFE/FEP lining and an outer supporting structure of nitinol wire. Clinical evaluation, assessment of serum bilirubin and liver enzyme levels were analyzed before biliary drainage, before stent-graft placement and during the follow-up period at 1, 3, 6, 9 and 12 months. Technical success was obtained in all cases. After a mean follow-up of 6.9{+-}4.63 months, the 30-day mortality rate was 14.2%. Survival rates were 40% and 20.2% at 6 and 12 months, respectively. Stent-graft patency rates were 95.5%, 92.6% and 85.7% at 3, 6 and 12 months, respectively. Complications occurred in five patients (6.4%); among these, acute cholecystitis was observed in three patients (3.8%). A stent-graft occlusion rate of 9% was observed. The percentage of patients undergoing lifetime palliation (91%) and the midterm patency rate suggest that placement of this ePTFE/FEP-covered stent-graft is safe and highly effective in achieving biliary drainage in patients with malignant strictures of the common bile duct. (orig.)

USE OF COVERED SELF-EXPANDABLE NITINOL STENT FOR ANASTOMOTIC BILIARY STRUCTURE MANAGEMENT AFTER LIVER TRANSPLANTATION: THE FIRST EXPERIENCE

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M. N. Kornilov

2013-01-01

Full Text Available Aim. The aim of this study focuses on the first experience with self-expandable stents, analysis of its efficacy and safety in the treatment of anastomotic strictures after liver transplantation. Materials and methods. There’re 136 liver transplantations performed from 2004 till 2012. To correct anastomotic strictures we’ve used only the self-expandable coated nitinol stent. We performed stenting in 7 recipient. Result. In 131 liver transplant recipients incidence of biliary strictures has been 5.3%. All of 5 patients have been managed by retrograde or antegrade way. Conclusion. Our first experience demonstrate efficacy and safety of the used tecniques up to 24 months. The analysis of more long-term results is required. 

Management of acute cholangitis as a result of occlusion from a self-expandable metallic stent in patients with malignant distal and hilar biliary obstructions.

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Shiomi, Hideyuki; Matsumoto, Kazuya; Isayama, Hiroyuki

2017-04-01

Acute cholangitis as a result of common bile duct stones can be managed; however, cholangitis caused by occlusion with a biliary self-expandable metallic stent (SEMS) in patients with an unresectable malignant biliary obstruction has not been fully discussed. The acute cholangitis clinical guidelines (Tokyo Guidelines 2013) recommend following the same procedure as that used for cholangitis; however, the patient's condition, including performance status, tumor extension or staging, and prognosis must be considered. Most physicians manage cholangitis from a SEMS occlusion using a two-step procedure. They insert endoscopic drainage with a plastic stent or insert a nasobiliary drainage tube, which does not exacerbate sepsis. Addition or replacement of a biliary SEMS is required in many cases depending on the cause of the occlusion. Tumor ingrowth through the stent mesh is common in uncovered SEMS and requires placement of another stent in an in-stent method. However, covered SEMS tends to be occluded by sludge, so it must be replaced because of the bacterial biofilm that forms on the covering membrane. The location of the biliary stricture (hilar or distal) should also be considered. Strategies for managing cholangitis as a result of occlusion by a biliary SEMS remain controversial, so prospective clinical trials are needed. © 2017 The Authors. Digestive Endoscopy © 2017 Japan Gastroenterological Endoscopy Society.

Comparison of self-expandable and balloon-expanding stents for hybrid ductal stenting in hypoplastic left heart complex.

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Goreczny, Sebastian; Qureshi, Shakeel A; Rosenthal, Eric; Krasemann, Thomas; Nassar, Mohamed S; Anderson, David R; Morgan, Gareth J

2017-07-01

We aimed to compare the procedural and mid-term performance of a specifically designed self-expanding stent with balloon-expandable stents in patients undergoing hybrid palliation for hypoplastic left heart syndrome and its variants. The lack of specifically designed stents has led to off-label use of coronary, biliary, or peripheral stents in the neonatal ductus arteriosus. Recently, a self-expanding stent, specifically designed for use in hypoplastic left heart syndrome, has become available. We carried out a retrospective cohort comparison of 69 neonates who underwent hybrid ductal stenting with balloon-expandable and self-expanding stents from December, 2005 to July, 2014. In total, 43 balloon-expandable stents were implanted in 41 neonates and more recently 47 self-expanding stents in 28 neonates. In the balloon-expandable stents group, stent-related complications occurred in nine patients (22%), compared with one patient in the self-expanding stent group (4%). During follow-up, percutaneous re-intervention related to the ductal stent was performed in five patients (17%) in the balloon-expandable stent group and seven patients (28%) in self-expanding stents group. Hybrid ductal stenting with self-expanding stents produced favourable results when compared with the results obtained with balloon-expandable stents. Immediate additional interventions and follow-up re-interventions were similar in both groups with complications more common in those with balloon-expandable stents.

In Vitro Comparison of Self-Expanding Versus Balloon-Expandable Stents in a Human Ex Vivo Model

International Nuclear Information System (INIS)

Grenacher, Lars; Rohde, Stefan; Gaenger, Ellen; Deutsch, Jochen; Kauffmann, Guenter W.; Richter, Goetz M.

2006-01-01

The objective was to compare the radial strength and expansile precision of self-expanding stents and balloon-expandable stents in a human cadaver bifurcation model. Seven different self-expanding (LUMINEXX, JOSTENT SelfX, JOSTENT SelfX hrf, Sinus-Repo, Sinus SuperFlex, Easy Wallstent, SMART) and four different balloon-expandable stent models (Palmaz, Sinus Stent, SAXX Medium, JOSTENT peripheral), each type 10 stents (total n = 110 stents) were implanted into the common iliac arteries of human cadaver corpses. The maximum stent diameter was 10 mm for all models. After stent implantation, the specimens were filled with silicone caoutchouc. After 24 h, the vascular walls including the stents were removed from the hardened casts. Diameters were taken and the weight of the cast cylinders was measured in air and in purified water to calculate the volume of the bodies (according to Archimedes Law) as a relative but precise degree for the radial strength of the implanted stents. The cylindrical casts of the self-expanding stents showed lower mean diameters (8.2 ± 1.0 mm) and mean volumes (0.60 ± 0.14 ml/cm) than in the balloon-expandable stent group (10.1 ± 0.3 mm and 0.71 ± 0.04 ml/cm, respectively; p < 0.01). The nominal maximum diameter of 10 mm was not achieved in any of the self-expanding stents, but this was achieved in more than 70% (29/40) of the balloon-expandable stent specimens (p < 0.05). The variation between achieved volumes was significantly larger in self-expanding (range: 0.23-0.78 ml/cm) than in balloon-expandable stents (range: 0.66-0.81 ml/cm; p < 0.05). Self-expanding stents presented considerably lower radial expansion force and lower degree of precision than balloon-expandable stents

Self-Expandable Metallic Stent for the Palliative Treatment of Obstructing Left-Sided Colorectal Cancer under Fluoroscopic Guidance: A Comparison of the Clinical Results according to Stent Diameter

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Kang, Pyeong Guk; Hong, Hyun Pyo; Choi, Yoon Jung; Lee, Min Hee; Park, Hae Won; Chung, Eun Chul [Kangbuk Samsung Hospital, Seoul (Korea, Republic of); Kim, Sam Soo [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of)

2010-03-15

To evaluate the feasibility, effectiveness, and safety of self-expandable metallic stent for the palliative treatment of obstructing left-sided colorectal cancer under fluoroscopic guidance, and to compare results according to the stent diameter. Under fluoroscopic guidance, 31 self-expandable metallic stents were placed into 25 patients for palliative purposes. The rates of technical success, clinical success, complications associated with stent insertion, patient survival, and primary stent patency were evaluated. The results were also compared between two groups: 13 patients using stents with a diameter of 22 mm and 12 patients using stents with a diameter of 26 mm. The technical and clinical success rates were 93.5 and 90.3%, respectively. The complications included severe abdominal pain (6.5%), minor rectal bleeding (9.7%), stent migration (9.7%), and tumor ingrowth or overgrowth (9.7%). No statistical differences in technical were detected between the two groups for the clinical success rate and complication rates. The mean survival time was 5.5 +- 1.4 months. The primary stent patency rates were 91.3% at 5 months, 85.2% at 10 months, and 77.4% at 15 months. The mean period of stent patency was 12.4 +- 2.6 months. The mean period of primary stent patency was 16.4 +- 2.6 months in the 26 mm stent group, and significantly higher than 5.4 +- 1.4 months in the 22 mm stent group (p=0.031). A self-expandable metallic stent under fluoroscopic guidance, for the palliative treatment of obstructing left-sided colorectal cancer, was feasible and effective, and yielded good clinical results. The period of primary stent patency of the 26 mm stent group was longer than the 22 mm stent group, and the complication rate was not significantly different between the two stent groups

Self-Expandable Metallic Stent for the Palliative Treatment of Obstructing Left-Sided Colorectal Cancer under Fluoroscopic Guidance: A Comparison of the Clinical Results according to Stent Diameter

International Nuclear Information System (INIS)

Kang, Pyeong Guk; Hong, Hyun Pyo; Choi, Yoon Jung; Lee, Min Hee; Park, Hae Won; Chung, Eun Chul; Kim, Sam Soo

2010-01-01

To evaluate the feasibility, effectiveness, and safety of self-expandable metallic stent for the palliative treatment of obstructing left-sided colorectal cancer under fluoroscopic guidance, and to compare results according to the stent diameter. Under fluoroscopic guidance, 31 self-expandable metallic stents were placed into 25 patients for palliative purposes. The rates of technical success, clinical success, complications associated with stent insertion, patient survival, and primary stent patency were evaluated. The results were also compared between two groups: 13 patients using stents with a diameter of 22 mm and 12 patients using stents with a diameter of 26 mm. The technical and clinical success rates were 93.5 and 90.3%, respectively. The complications included severe abdominal pain (6.5%), minor rectal bleeding (9.7%), stent migration (9.7%), and tumor ingrowth or overgrowth (9.7%). No statistical differences in technical were detected between the two groups for the clinical success rate and complication rates. The mean survival time was 5.5 ± 1.4 months. The primary stent patency rates were 91.3% at 5 months, 85.2% at 10 months, and 77.4% at 15 months. The mean period of stent patency was 12.4 ± 2.6 months. The mean period of primary stent patency was 16.4 ± 2.6 months in the 26 mm stent group, and significantly higher than 5.4 ± 1.4 months in the 22 mm stent group (p=0.031). A self-expandable metallic stent under fluoroscopic guidance, for the palliative treatment of obstructing left-sided colorectal cancer, was feasible and effective, and yielded good clinical results. The period of primary stent patency of the 26 mm stent group was longer than the 22 mm stent group, and the complication rate was not significantly different between the two stent groups

Radioactive metallic stent for the treatment of esophageal cancer in animal model and clinical trial

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Park, K. B. [Korea Atomic Energy Research Institute, Taejeon (Korea); Lee, J. D. [Yonsei Univ., Seoul (Korea)

2000-03-01

The purpose of this study is to evaluate tissue response of self-expandable metallic stent covered Ho-166 in normal canine esophagus. Ho-166 was incorporated within polyurethan and covered over the outer surface of self-expandable metallic stents(diameter ; 18mm, length ; 40mm). Metallic stents with radioactivity of 4.0-7.8mCi (Group A), 1.0-1.8mCi (Group B) and 0.5-0.7mCi (Group C) were placed in normal mid-esophagus in twelve dogs (Group A), five (Group B) and another five dogs (Group C) respectively. Estimated radiation dose was 200-392Gy in Group A, 50-90Gy in Group B, and 25-35 Gy in Group C. The dogs were sacrified at two or three months later. In group A, mid-esophagus stricture, mucosal ulceration were found. Sereve fibrosis and degeneration of muscular propria, outer one half were found in three and complete fibrosis of esophageal wall in seven and fibrosis of esophageal wall and periesophageal soft tissue in two. In group B, glandular atrophy and submucosal fibrosis were found but muscular layer was intact. In group C, no histological change was demonstrated in three but submucosal inflammation and glandular atrophy with intact mucosa in two. Self-expandable metallic stent covered with Ho-166 may be used safely in esophagus without complication. 21 refs., 17 figs., 2 tabs. (Author)

Fully-covered metal stents with endoscopic suturing vs. partially-covered metal stents for benign upper gastrointestinal diseases: a comparative study

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Ngamruengphong, Saowanee; Sharaiha, Reem; Sethi, Amrita; Siddiqui, Ali; DiMaio, Christopher J.; Gonzalez, Susana; Rogart, Jason; Jagroop, Sophia; Widmer, Jessica; Im, Jennifer; Hasan, Raza Abbas; Laique, Sobia; Gonda, Tamas; Poneros, John; Desai, Amit; Wong, Katherine; Villgran, Vipin; Brewer Gutierrez, Olaya; Bukhari, Majidah; Chen, Yen-I; Hernaez, Ruben; Hanada, Yuri; Sanaei, Omid; Agarwal, Amol; Kalloo, Anthony N.; Kumbhari, Vivek; Singh, Vikesh; Khashab, Mouen A.

2018-01-01

Background and study aims  Self-expandable metallic stents (SEMS) have been increasingly used in benign conditions (e. g. strictures, fistulas, leaks, and perforations). Fully covered SEMS (FSEMS) were introduced to avoid undesirable consequences of partially covered SEMS (PSEMS), but come with higher risk of stent migration. Endoscopic suturing (ES) for stent fixation has been shown to reduce migration of FSEMS. Our aim was to compare the outcomes of FSEMS with ES (FS/ES) versus PSEMS in patients with benign upper gastrointestinal conditions. Patients and methods  We retrospectively identified all patients who underwent stent placement for benign gastrointestinal conditions at seven US tertiary-care centers. Patients were divided into two groups: FSEMS with ES (FS/ES group) and PSEMS (PSEMS group). Clinical outcomes between the two groups were compared. Results  A total of 74 (FS/ES 46, PSEMS 28) patients were included. On multivariable analysis, there was no significant difference in rate of stent migration between FS/ES (43 %) and PSEMS (15 %) (adjusted odds ratio 0.56; 95 % CI 0.15 – 2.00). Clinical success was similar [68 % vs. 64 %; P  = 0.81]. Rate of adverse events (AEs) was higher in PSEMS group [13 (46 %) vs. 10 (21 %); P  = 0.03). Difficult stent removal was higher in the PSEMS group (n = 5;17 %) vs. 0 % in the FS/ES group; P  = 0.005. Conclusions  The proportion of stent migration of FS/ES and PSEMS are similar. Rates of other stent-related AEs were higher in the PSEMS group. PSEMS was associated with tissue ingrowth or overgrowth leading to difficult stent removal, and secondary stricture formation. Thus, FSEMS with ES for stent fixation may be the preferred modality over PSEMS for the treatment of benign upper gastrointestinal conditions. PMID:29404384

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique.

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Patrzyk, Maciej; Dierzek, Przemyslaw; Glitsch, Anne; Paul, Hartmut; Heidecke, Claus-Dieter

2015-01-01

Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique) approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ½ year observation period.

Second Generation Self-Inflating Tissue Expanders: A Two-Year Experience

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Jamal Omran Al Madani

2014-01-01

Full Text Available Background. Tissue expansion is a well-established surgical technique that produces an additional amount of normal skin to cover a defect. This technique is appealing because the skin quality and color are from the patient’s own. The widely used injectable expanders are of great reliability but carry the disadvantage of being painful during injection and most of the time require multiple clinic visits. So the idea of self-inflation became attractive and hydrogel expanders were developed and became widely known for being painless during clinic visit and decrease number of visits. The first generation expanders were modified by adding an enclosing plastic shell to decrease the unopposed expansion that occurred in the first generation expanders, which lead to pressure necrosis of the skin flaps. This made it an attractive option for tissue expansion in children and some adult patients. Patients, Materials, and Methods. Charts of 17 patients were retrospectively reviewed, all of them had second generation self-inflating expanders implanted over a 2-year period for one of two purposes, the treatment of giant nevi or burn scars. Results. Fifteen patients were females and 2 were males. The indication was large burn scar in 14 cases (14/17, in which 47/55 expanders were implanted, and giant nevus in 3/17 cases in which 8/55 expanders were implanted. Extrusion of the expander occurred in 8/55 expanders (14.5%, which occurred in 6/14 patients. The highest percentage of extrusion occurred in the neck in which two out of three expanders extruded; otherwise this complication does not seem to be related to the indication, gender, nor age of the patients. It seems to be that it is technical in nature. The patients did not have to get any injections to fill the tissue expanders, which made the expansion process less painful and more convenient. Conclusion. This seems to be currently the largest published review in which second generation expanders were used

Complications related to conventional self-expandable metal stent insertion and internal irradiation stent insertion in patients with advanced esophageal carcinoma: an analysis of 32 cases

International Nuclear Information System (INIS)

Xu Xingwen; Di Haiting; Zhu Jun; Shi Jian

2011-01-01

Objective: To compare the occurrence of complications between conventional self-expandable metal stent and internal irradiation stent insertion in treating patients with advanced esophageal carcinomas. Methods: A total of 32 patients with advanced esophageal carcinoma were randomly divided into irradiation stent group (n=15) and conventional stent group (n=17). Internal irradiation stent loaded with 125 I seeds was employed in patients of irradiation stent group, while conventional self-expandable metal stent was used in patients of conventional stent group. After the treatment, clinical follow-up was regularly conducted. Postoperative complications such as fever, severe chest pain, cough, esophageal perforation, pneumonia, hemorrhage, stent migration and restenosis, etc. were observed. Results: No significant difference in the occurrence of fever, severe chest pain, esophageal perforation and hemorrhage existed between the two groups (P>0.05). The difference in the occurrence of long-term complications such as stent migration or restenosis between the two groups was out statistically significant (P>0.05). However, the restenosis in irradiation stent group occurred obviously much later than that in conventional stent group. Conclusion: For the treatment of advanced esophageal carcinomas, the insertion of internal irradiation esophageal stent is safe. It dose not increase the incidence of postoperative complications. Therefore, it is worth popularizing this technique in clinical practice. (authors)

Medium-term follow-up after deployment of ultraflex expandable metallic stents to manage endobronchial pathology.

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Madden, Brendan P; Park, John E S; Sheth, Abhijat

2004-12-01

Between March 1997 and March 2004 we deployed 80 Ultraflex metallic expandable stents (Boston Scientific, Waterson, MA) in 69 patients under direct vision using rigid bronchoscopy. We report our medium- to long-term experience in patients for whom these stents were deployed. To date 15 patients have been followed for more than 1 year (median 41 months, range 12 to 83 months) after stent deployment. Indications for stenting in these patients were neoplasia (5), stricture (5), airway malacia (1), iatrogenic tracheal tear (1), and compression from an aortic aneurysm (1), a right interrupted aortic arch (1), and a right brachiocephalic artery aneurysm with tracheomalacia (1). Ten tracheal stents (9 covered, 1 uncovered) and 10 bronchial stents (8 uncovered, 2 covered) were inserted, and 5 patients received two stents. Five of these patients experienced no long-term problems. Complications included troublesome halitosis (5), which was difficult to treat despite various antibiotic regimes; granulation tissue formation above and below the stent that was successfully treated with low-power Nd:YAG laser therapy (7); and metal fatigue (1). We did not encounter stent migration. We conclude that Ultraflex expandable metallic stents have an important role in the management of selected patients with diverse endobronchial pathologies and are well tolerated in the long-term. Although associated granulation tissue can be successfully treated with Nd:YAG laser, halitosis can be a difficult problem to address.

Thermodynamically self-consistent integral equations and the structure of liquid metals

International Nuclear Information System (INIS)

Pastore, G.; Kahl, G.

1987-01-01

We discuss the application of the new thermodynamically self-consistent integral equations for the determination of the structural properties of liquid metals. We present a detailed comparison of the structure (S(q) and g(r)) for models of liquid alkali metals as obtained from two thermodynamically self-consistent integral equations and some published exact computer simulation results; the range of states extends from the triple point to the expanded metal. The theories which only impose thermodynamic self-consistency without any fitting of external data show an excellent agreement with the simulation results, thus demonstrating that this new type of integral equation is definitely superior to the conventional ones (hypernetted chain, Percus-Yevick, mean spherical approximation, etc). (author)

Expandable metallic stents for tracheobronchial stenoses in esophageal cancer.

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Takamori, S; Fujita, H; Hayashi, A; Tayama, K; Mitsuoka, M; Ohtsuka, S; Shirouzu, K

1996-09-01

Tracheobronchial stenosis in patients with esophageal cancer can be life threatening. Few reports have discussed use of expandable metallic stents for central airway stenoses in patients with esophageal cancer. Twelve patients with esophageal cancer underwent placement of expandable metallic stents for respiratory distress caused by tracheobronchial stricture. Single or double metallic stents were placed in the stenotic airways under fluoroscopic guidance. Improvement in respiratory symptoms and clinical outcome were assessed. Most stenoses were located in the trachea or the left main bronchus. From one to four expandable metallic stents were placed in each stricture site, with immediate relief of respiratory symptoms in 8 patients. One patient with tracheomalacia in alive 3 years after stent placement and another is alive 6 months after stent insertion. The other 10 patients lived from 10 to 70 days (mean; survival, 35 days) after stent placement. Death was due to progression of disease. Although metallic stents are useful for relieving respiratory distress in patients with advanced esophageal cancer, additional therapies should be considered.

Expandable stents.

Science.gov (United States)

Nesbitt, J C; Carrasco, H

1996-05-01

Expandable metallic stents are effective in selected patients with malignant or benign airway stenoses. When used for malignant lesions, the primary purpose of the stent is to improve the quality of life; stents are usually chosen for palliation of symptoms in recognition of the low likelihood of success for other therapy. For patients with benign stenoses, the stents provide a permanent source of structural support to alleviate the narrowed segment. The advantages of the expandable metallic stents are as follows: (1) they can be inserted through an endotracheal tube or under local anesthesia with relative simplicity under fluoroscopic guidance; (2) they do not impair the drainage of sputum because ciliary movement is not interrupted; (3) over a period of a few weeks, the meshwork is gradually covered with mucosa as the stent becomes incorporated into the airway wall; (4) ventilation usually is not impaired if the metallic mesh stent covers another nonstenosed bronchus, because the interstices of the stent are nonobstructive; and (5) they are dynamic and continue to expand over time, particularly if concurrent treatment achieves an effect on the lesion that caused stenosis. Disadvantages of the expandable stent include (1) they often are only temporarily effective for tracheobronchial stenosis due to intraluminal tumor or granulation tissue, both of which can grow between the wires; (2) they are considered permanent stents because removal is difficult; and (3) they can be poorly positioned during placement or can become displaced by progressive migration after placement, and they cannot be repositioned. A relative contraindication to insertion is an inflammatory process or infection that can predispose to granulation formation, particularly at the points of maximal contact pressure of the stent to the airway mucosa. In the presence of inflammation, it may be better to use a silicone prosthesis until the inflammatory process subsides and fibrosis occurs. Granulation

Treatment of Benign and Malignant Tracheobronchial Obstruction with Metal Wire Stents: Experience with a Balloon-Expandable and a Self-Expandable Stent Type

International Nuclear Information System (INIS)

Rieger, Johannes; Hautmann, Hubert; Linsenmaier, Ulrich; Weber, Cristoph; Treitl, Markus; Huber, R.M.; Pfeifer, Klaus-Juergen

2004-01-01

Over the last few years various types of metal wire stents have been increasingly employed in the treatment of both malignant and benign tracheobronchial obstruction. To date, however, few studies have investigated the in vivo properties of different stent types. We implanted 26 balloon-expandable tantalum Strecker stents (18 patients) and 18 self-expandable Wallstents (16 patients) into the tracheobronchial system of 30 patients with combined stenting in 4 patients. Mean age was 51 years (range: 0.5-79 years). Malignant disease was present in 23 patients, benign disease in seven patients. Both patients and individual stents were monitored clinically and radiographically. The probability of stents remaining within the tracheobronchial system, and of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for both stent types. Average stent follow-up time was 112 days until explantation and 115 days until patients' death or discharge. Kaplan-Meier analysis revealed a higher probability for the Wallstent to remain within the tracheobronchial system. Dislocation and compression occurred more rarely. Explantation, however, if desired, was more difficult compared to the Strecker stent. The Wallstent also led to the formation of granulation tissue, especially at the proximal stent end, frequently requiring reintervention. Both stent types proved to be effective therapeutic options in the management of obstructive tracheobronchial disease. The mechanical properties of the Strecker stent seem to be less favorable compared to the Wallstent but removal is easy. For benign disease, however, the Wallstent reveals limitations due to significant side effects

Radiologic placement of metallic esophageal stents: preliminary experience

International Nuclear Information System (INIS)

Good, S.; Asch, M.R.; Jaffer, N.; Casson, A.G.

1997-01-01

To assess the usefulness of covered, self expanding metallic stents for alleviating stricture associated with malignant esophageal lesions. Patients and methods: Self-expanding metallic stents were placed in 10 patients with dysphagia related to stricture caused by malignant esophageal lesions. The stents were placed fluoroscopically with local anesthesia, and patency of the esophageal lumen was assessed by barium study after the procedure. The patients were then followed clinically. Results: In all 10 cases patency of the lumen was renewed after stent placement. After the procedure 9 of the patients could tolerate a normal or near-normal diet; in the other patient esophageal perforation occurred, and clinical deterioration prevented oral intake of food. In one patient, 2 stents were needed because of the length of the stricture. Two patients experienced reflux after placement of the stent across the gastro-esophageal junction. Another patient had asymptomatic aspiration after stent placement in the proximal esophagus. In 2 patients, symptoms associated with tracheoesophageal fistula were relieved after placement of the stents. Six of the 10 patients died; mean survival after the procedure was 12 (range 1 to 56) weeks. The other 4 patients were alive at the time of writing, having survived for a mean of 7.5 (range 2 to 13) weeks; all of these patients tolerated a near-normal diet. Conclusions: The placement of covered, self-expanding metallic stents is a quick, effective method of palliating dysphagia related to stricture caused by malignant esophageal lesions. (author)

A non-randomized study in consecutive patients with postcholecystectomy refractory biliary leaks who were managed endoscopically with the use of multiple plastic stents or fully covered self-expandable metal stents (with videos).

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Canena, Jorge; Liberato, Manuel; Meireles, Liliane; Marques, Inês; Romão, Carlos; Coutinho, António Pereira; Neves, Beatriz Costa; Veiga, Pedro Mota

2015-07-01

Endoscopic management of postcholecystectomy biliary leaks is widely accepted as the treatment of choice. However, refractory biliary leaks after a combination of biliary sphincterotomy and the placement of a large-bore (10F) plastic stent can occur, and the optimal rescue endotherapy for this situation is unclear. To compare the clinical effectiveness of the use of a fully covered self-expandable metal stent (FCSEMS) with the placement of multiple plastic stents (MPS) for the treatment of postcholecystectomy refractory biliary leaks. Prospective study. Two tertiary-care referral academic centers and one general district hospital. Forty consecutive patients with refractory biliary leaks who underwent endoscopic management. Temporary placement of MPS (n = 20) or FCSEMSs (n = 20). Clinical outcomes of endotherapy as well as the technical success, adverse events, need for reinterventions, and prognostic factors for clinical success. Endotherapy was possible in all patients. After endotherapy, closure of the leak was accomplished in 13 patients (65%) who received MPS and in 20 patients (100%) who received FCSEMSs (P = .004). The Kaplan-Meier (log-rank) leak-free survival analysis showed a statistically significant difference between the 2 patient populations (χ(2) [1] = 8.30; P stents (P = .024), a plastic stent diameter <20F (P = .006), and a high-grade biliary leak (P = .015) were shown to be significant predictors of treatment failure with MPS. The 7 patients in whom placement of MPS failed were retreated with FCSEMSs, resulting in closure of the leaks in all cases. Non-randomized design. In our series, the results of the temporary placement of FCSEMSs for postcholecystectomy refractory biliary leaks were superior to those from the use of MPS. A randomized study is needed to confirm our results before further recommendations. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Retrieval of a self-expanding metal stent after migration and incorporation in the omental bursa, using a gastroscopic-transgastric laparoscopic rendezvous technique

Directory of Open Access Journals (Sweden)

Maciej Patrzyk

2015-01-01

Full Text Available Endoscopic drainage is a widely used treatment for pancreatic pseudocysts. Drainage-related complications may be related directly to the procedure or may occur later as stents migrate or erode into adjacent structures. Migration of a self-expanding metal stent into peritoneal cavity and incorporation in the omental bursa is rare. When endoscopic retrieval fails a combined laparoscopic-endoscopic (rendezvous technique approach offers an alternative to open surgery. We report a case of successful gastroscopic-transgastric laparoscopic removal of a stent that was dislocated into the omental bursa after a ΍ year observation period.

Efficacy and safety of limited endoscopic sphincterotomy before self-expandable metal stent insertion for malignant biliary obstruction.

Science.gov (United States)

Nam, Hyeong Seok; Kang, Dae Hwan; Kim, Hyung Wook; Choi, Cheol Woong; Park, Su Bum; Kim, Su Jin; Ryu, Dae Gon

2017-03-07

To evaluate the safety and efficacy of limited endoscopic sphincterotomy (ES) before placement of self-expandable metal stent (SEMS). This was a retrospective analysis of 244 consecutive patients with unresectable malignant biliary obstruction, who underwent placement of SEMSs following limited ES from December 2008 to February 2015. The diagnosis of malignant biliary obstruction and assessment of patient eligibility for the study was established by a combination of clinical findings, laboratory investigations, imaging and pathological results. All patients were monitored in the hospital for at least 24 h following endoscopic retrograde cholangio pancreatography (ERCP). The incidence of immediate or early post-ERCP complications such as post-ERCP pancreatitis (PEP) and bleeding related to limited ES were considered as primary outcomes. Also, characteristics and complications according to the cancer type were classified. Among the 244 patients included, the underlying diagnosis was cholangiocarcinoma in 118 patients, pancreatic cancer in 79, and non-pancreatic or non-biliary malignancies in the remaining 47 patients. Early post-ERCP complications occurred in 9 patients (3.7%), with PEP in 7 patients (2.9%; mild, 6; moderate, 1) and mild bleeding in 2 patients (0.8%). There was no significant association between the incidence of post-ERCP complications and the type of malignancy (cholangiocarcinoma vs pancreatic cancer vs others, P = 0.696) or the type of SEMS used (uncovered vs covered, P = 1.000). Patients who had more than one SEMS placed at the first instance were at a significantly higher risk of post-ERCP complications (one SEMS vs two SEMS, P = 0.031). No other factors were predictive of post-ERCP complications. Limited ES is feasible and safe, and effectively facilitates the placement of SEMS, without any significant risk of PEP or severe bleeding.

Covered Metal Stenting for Malignant Lower Biliary Stricture with Pancreatic Duct Obstruction: Is Endoscopic Sphincterotomy Needed?

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Kazunari Nakahara

2013-01-01

Full Text Available Aims. To evaluate the need for endoscopic sphincterotomy (EST before covered self-expandable metal stent (CSEMS deployment for malignant lower biliary stricture with pancreatic duct obstruction. Methods. This study included 79 patients who underwent CSEMS deployment for unresectable malignant lower biliary stricture with pancreatic duct obstruction. Treatment outcomes and complications were compared between 38 patients with EST before CSEMS deployment (EST group and 41 without EST (non-EST group. Results. The technical success rates were 100% in both the EST and the non-EST group. The incidence of pancreatitis was 2.6% in the EST, and 2.4% in the non-EST group (. The incidences of overall complications were 18.4% and 14.6%, respectively, (. Within the non-EST groups, the incidence of pancreatitis was 0% in patients with fully covered stent deployment and 3.6% in those with partially covered stent deployment (. In the multivariate analysis, younger age (, OR 12 and nonpancreatic cancer (, OR 24 were significant risk factors for overall complications after CSEMS deployment. EST was not identified as a risk factor. Conclusions. EST did not reduce the incidence of pancreatitis after CSEMS deployment in patients of unresectable distal malignant obstruction with pancreatic duct obstruction.

Delayed ischemic cecal perforation despite optimal decompression after placement of a self-expanding metal stent: report of a case

DEFF Research Database (Denmark)

Knop, Filip Krag; Pilsgaard, Bo; Meisner, Søren

2004-01-01

Endoscopic deployment of self-expanding metal stents offers an alternative to surgical intervention in rectocolonic obstructions. Reported clinical failures in the literature are all related to the site of stent placement. We report a case of serious intra-abdominal disease after technically...... and clinically successful stent deployment: a potentially dangerous situation of which the surgeon should be aware. A previously healthy 72-year-old female was referred to our department with symptoms of an obstructing colorectal tumor. Successful stent placement resulted in resolution of the obstructive...... condition. Three days after stent deployment, x-ray examinations revealed a small-bowel obstruction and emergency surgery was performed. Intraoperative findings demonstrated a segment of ileum fixated to the tumor in the small pelvis, resulting in the obstructive condition. Furthermore, a cecal perforation...

Tracheal Self-Expandable Metallic Stents: A Comparative Study of Three Different Stents in a Rabbit Model.

Science.gov (United States)

Serrano, Carolina; Lostalé, Fernando; Rodríguez-Panadero, Francisco; Blas, Ignacio de; Laborda, Alicia; de Gregorio, Miguel Angel

2016-03-01

The objective of this study was to assess tracheal reactivity after the deployment of different self-expandable metal stents (SEMS). Forty female New Zealand rabbits were divided into four groups. Three groups received three different SEMS: steel (ST), nitinol (NiTi), or nitinol drug-eluting stent (DES); the fourth group was the control group (no stent). Stents were deployed percutaneously under fluoroscopic guidance. Animals were assessed by multi-slice, computed tomography (CT) scans, and tracheas were collected for anatomical pathology (AP) study. Data from CT and AP were statistically analyzed and correlated. The DES group had the longest stenosis (20.51±14.08mm vs. 5.84±12.43 and 6.57±6.54mm in NiTi and ST, respectively, day 30; Pstent. CT was more effective in detecting wall thickening (positive correlation of 68.9%; Pstent, while DES caused significant lesions that may be related to drug dosage. This type of DES stent is therefore not recommended for the treatment of tracheobronchial stenosis. Copyright © 2015 SEPAR. Published by Elsevier Espana. All rights reserved.

Self-expanding/shrinking structures by 4D printing

Science.gov (United States)

Bodaghi, M.; Damanpack, A. R.; Liao, W. H.

2016-10-01

The aim of this paper is to create adaptive structures capable of self-expanding and self-shrinking by means of four-dimensional printing technology. An actuator unit is designed and fabricated directly by printing fibers of shape memory polymers (SMPs) in flexible beams with different arrangements. Experiments are conducted to determine thermo-mechanical material properties of the fabricated part revealing that the printing process introduced a strong anisotropy into the printed parts. The feasibility of the actuator unit with self-expanding and self-shrinking features is demonstrated experimentally. A phenomenological constitutive model together with analytical closed-form solutions are developed to replicate thermo-mechanical behaviors of SMPs. Governing equations of equilibrium are developed for printed structures based on the non-linear Green-Lagrange strain tensor and solved implementing a finite element method along with an iterative incremental Newton-Raphson scheme. The material-structural model is then applied to digitally design and print SMP adaptive lattices in planar and tubular shapes comprising a periodic arrangement of SMP actuator units that expand and then recover their original shape automatically. Numerical and experimental results reveal that the proposed planar lattice as meta-materials can be employed for plane actuators with self-expanding/shrinking features or as structural switches providing two different dynamic characteristics. It is also shown that the proposed tubular lattice with a self-expanding/shrinking mechanism can serve as tubular stents and grippers for bio-medical or piping applications.

Self-Expandable Metal Stents for Persisting Esophageal Variceal Bleeding after Band Ligation or Injection-Therapy: A Retrospective Study.

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Martin Müller

Full Text Available Despite a pronounced reduction of lethality rates due to upper gastrointestinal bleeding, esophageal variceal bleeding remains a challenge for the endoscopist and still accounts for a mortality rate of up to 40% within the first 6 weeks. A relevant proportion of patients with esophageal variceal bleeding remains refractory to standard therapy, thus making a call for additional tools to achieve hemostasis. Self-expandable metal stents (SEMS incorporate such a tool.We evaluated a total number of 582 patients admitted to our endoscopy unit with the diagnosis "gastrointestinal bleeding" according to our documentation software between 2011 and 2014. 82 patients suffered from esophageal variceal bleeding, out of which 11 cases were refractory to standard therapy leading to SEMS application. Patients with esophageal malignancy, fistula, or stricture and a non-esophageal variceal bleeding source were excluded from the analysis. A retrospective analysis reporting a series of clinically relevant parameters in combination with bleeding control rates and adverse events was performed.The initial bleeding control rate after SEMS application was 100%. Despite this success, we observed a 27% mortality rate within the first 42 days. All of these patients died due to non-directly hemorrhage-associated reasons. The majority of patients exhibited an extensive demand of medical care with prolonged hospital stay. Common complications were hepatic decompensation, pulmonary infection and decline of renal function. Interestingly, we found in 7 out of 11 patients (63.6% stent dislocation at time of control endoscopy 24 h after hemostasis or at time of stent removal. The presence of hiatal hernia did not affect obviously stent dislocation rates. Refractory patients had significantly longer hospitalization times compared to non-refractory patients.Self-expandable metal stents for esophageal variceal bleeding seem to be safe and efficient after failed standard therapy

Self-Expandable Metallic Stent Placement in Malignant Gastric Outlet Obstruction: A Comparison Between 2 Brands of Stents.

Science.gov (United States)

Ye, Bing-Wei; Lee, Kuei-Chuan; Hsieh, Yun-Cheng; Li, Chung-Pin; Chao, Yee; Hou, Ming-Chih; Lin, Han-Chieh

2015-07-01

Malignant gastric outlet obstruction is a late complication of intraabdominal malignancy. Self-expandable metallic stent placement has been a safe palliative treatment to relieve obstructive symptoms. We aimed to assess the efficacy and safety of metallic stents in our patients and analyzed the clinical outcome of different brands. Seventy-one patients with inoperable gastric outlet obstruction receiving WallFlex enteral stents (WallFlex group) or Bonastents (Bonastent group) since April 2010 were analyzed retrospectively. The overall technical and clinical success rates of stent placement were 100% and 93%, respectively. The baseline characteristics and clinical outcomes including procedure-related complications, restenosis, and reintervention rates were comparable between the 2 groups. However, the Bonastent group had a higher rate of stent fracture than the WallFlex group (13.3% vs 0%, P = 0.03). The mean duration of overall stent patency was 132.7 days. The mean duration of survival was 181.9 days. Resumption of regular diet or low residual diet at day 7 after stent insertion predicted stent patency (hazard ratio [HR]: 0.28, P = 0.01). Cancer with gastric origin (HR: 0.25, P = 0.045) and poststent chemotherapy (HR: 0.38, P = 0.006) predicted lower mortality; however, peritoneal carcinomatosis (HR: 3.09, P = 0.04) correlated with higher mortality. Metallic stent placement is a safe and effective method for relieving gastric outlet obstruction. Except higher rate of stent fracture in the Bonastent group, there is no significant difference in clinical outcomes between the Bonastent group and the WallFlex group.

Successful stent-in-stent insertion of an expandable metallic stent covered with polyuretane placed to obliterate a large bronchial fistula after chemoradiotherapy for inoperable lung cancer

International Nuclear Information System (INIS)

Minami, Hiroya; Tsubota, Noriaki; Miyamoto, Yoshifumi; Yoshimura, Masahiro; Obayashi, Kayoko; Takada, Yoshiki

1999-01-01

Bronchial fistulas in cases of inoperable lung cancer caused by radiochemotherapy are quite refractory and generally cannot be surgically closed. A 45-year-old man with squamous cell carcinoma in the right lung underwent two courses of induction chemotherapy (135 mg CDDP, 5 mg VDS, 13.5 mg MMC) and radiation therapy (2 Gy x 22 times) for invasion of the right main bronchus, the pulmonary artery and superior vena cava. Just before the end of the second course, the empyem second to the bronchial fistula caused by tumor necrosis developed in the right upper bronchus, and fenestration was performed. After the operation, his condition improved remarkably, however the fistula enlarged into the right main bronchus and the purulent discharge flowed into the left lung. An expandable metallic stent (EMS) covered with polyuretane was inserted in the trachea and the left main bronchus to break aspiration pneumonia. As the covered EMS was too unstable to be fixed, a bare EMS was inserted in a stent-in-stent fashion. After the procedure he was followed at the O.P.D. and lived a relatively comfortable life for 9 months until his death due to tumor. We inserted the covered EMS in a stent-in-stent fashion to successfully obliterate a large bronchial fistula. (author)

Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis

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Caroline Dahlqvist

2016-01-01

Full Text Available Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation, and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent’s tolerance and durability data. Results. Twenty-one stents were inserted: 13 for posttransplant left main bronchus anastomotic stricture, seven for postintubation tracheal stenosis, and one for postlobectomy anastomotic stricture. Positioning was easy for all of them. Stents were in place for a mean duration of 282 days. The most common complications were granulation tissue development (35%, migration (30%, and sputum retention (15%. Fifty-five % of the stents (11/20 had to be removed because of various complications, without difficulty for all of them. None of the patients had life-threatening complications. Conclusion. Micro-Tech FC-SEMS were easy to position and to remove. While the rate of complications requiring stent removal was significant, no life-threatening complication occurred. Further studies are needed to better define their efficacy and safety in the treatment of benign airway disease.

Fully Covered Metallic Stents for the Treatment of Benign Airway Stenosis.

Science.gov (United States)

Dahlqvist, Caroline; Ocak, Sebahat; Gourdin, Maximilien; Dincq, Anne Sophie; Putz, Laurie; d'Odémont, Jean-Paul

2016-01-01

Introduction. We herein report our experience with new fully covered self-expanding metallic stents in the setting of inoperable recurrent benign tracheobronchial stenosis. Methods. Between May 2010 and July 2014, 21 Micro-Tech® FC-SEMS (Nanjing Co., Republic of Korea) were placed in our hospital in 16 patients for inoperable, recurrent (after dilatation), and symptomatic benign airway stenosis. Their medical files were retrospectively reviewed in December 2014, with focus on stent's tolerance and durability data. Results. Twenty-one stents were inserted: 13 for posttransplant left main bronchus anastomotic stricture, seven for postintubation tracheal stenosis, and one for postlobectomy anastomotic stricture. Positioning was easy for all of them. Stents were in place for a mean duration of 282 days. The most common complications were granulation tissue development (35%), migration (30%), and sputum retention (15%). Fifty-five % of the stents (11/20) had to be removed because of various complications, without difficulty for all of them. None of the patients had life-threatening complications. Conclusion. Micro-Tech FC-SEMS were easy to position and to remove. While the rate of complications requiring stent removal was significant, no life-threatening complication occurred. Further studies are needed to better define their efficacy and safety in the treatment of benign airway disease.

Self-expendable metallic stents for palliative treatment of malignant esophagogastric strictures: experiences in 103 patients

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Ah; Do, Young Soo; Lee, Byung Hee; Oh, Hoon Il; Kim, Soo Ah; Kim, Ki Soo; Chin, Soo Yil [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1995-10-15

To evaluate the effects and complication of self-expandable metallic stent for the treatment of malignant esophagogastric strictures. From September 1991 to March 1995, 110 stents were placed under fluoroscopic guidance in 103 patients. Of the 103 patients, there were 73 patients with esophageal cancer, 14 patients with gastric cancer, 12 patients with recurrence after surgery, three patients with esophageal compression by metastatic mediastinal lymphadenopathy, and one patient with esophageal invasion by lung cancer. Seventeen patients had esophagorespiratory fistulas. Under fluoroscopic guidance, 113 self-expandable metallic stents (99 Song stents, 14 Strecker stents) were placed in 103 patients. After stent placement, 68 (66%) of the patients could ingest solid food, 26 (25.2%) could ingest soft food whereas three (2.9%) were not able to have food. Esophagorespiratory fistulas were occluded immediately after stent insertion. All stents were placed without any technical failures or procedural morbidity or mortality. Complications included restenosis in 13, gastroesophageal reflux in 11, stent tube migration in eight, massive bleeding in four, delayed esophageal perforation in one, stent obstruction by food impaction in one patient. Self-expandable metallic stent seems to be relatively safe and effective procedure in the palliative treatment of malignant esophagogastric stricture.

Proton dynamics in lithium-ammonia solutions and expanded metals.

Science.gov (United States)

Thompson, Helen; Skipper, Neal T; Wasse, Jonathan C; Spencer Howells, W; Hamilton, Myles; Fernandez-Alonso, Felix

2006-01-14

Quasielastic neutron scattering has been used to study proton dynamics in the system lithium-ammonia at concentrations of 0, 4, 12, and 20 mole percent metal (MPM) in both the liquid and solid (expanded metal) phases. At 230 K, in the homogenous liquid state, we find that the proton self-diffusion coefficient first increases with metal concentration, from 5.6x10(-5) cm2 s(-1) in pure ammonia to 7.8x10(-5) cm2 s(-1) at 12 MPM. At higher concentrations we note a small decrease to a value of 7.0x10(-5) cm2 s(-1) at 20 MPM (saturation). These results are consistent with NMR data, and can be explained in terms of the competing influences of the electron and ion solvation. At saturation, the solution freezes to form a series of expanded metal compounds of composition Li(NH3)4. Above the melting point, at 100 K, we are able to fit our data to a jump-diffusion model, with a mean jump length (l) of 2.1 A and residence time (tau) of 3.1 ps. This model gives a diffusion coefficient of 2.3x10(-5) cm2 s(-1). In solid phase I (cubic, stable from 88.8 to 82.2 K) we find that the protons are still undergoing this jump diffusion, with l=2.0 A and tau=3.9 ps giving a diffusion coefficient of 1.8x10(-5) cm2 s(-1). Such motion gives way to purely localized rotation in solid phases IIa (from 82.2 to 69 K) and IIb (stable from 69 to 25 K). We find rotational correlation times (tau(rot)) of the order of 2.0 and 7.3 ps in phases IIa and IIb, respectively. These values can be compared with a rotational mode in solid ammonia with tau(rot) approximately 2.4 ps at 150 K.

Effects of the temporary placement of a self-expandable metallic stent in benign pyloric stenosis.

Science.gov (United States)

Choi, Won Jae; Park, Jong-Jae; Park, Jain; Lim, Eun-Hye; Joo, Moon Kyung; Yun, Jae-Won; Noh, Hyejin; Kim, Sung Ho; Choi, Woo Seok; Lee, Beom Jae; Kim, Ji Hoon; Yeon, Jong Eun; Kim, Jae Seon; Byun, Kwan Soo; Bak, Young-Tae

2013-07-01

The use of self-expandable metallic stents (SEMS) is an established palliative treatment for malignant stenosis in the gastrointestinal tract; therefore, its application to benign stenosis is expected to be beneficial because of the more gradual and sustained dilatation in the stenotic portion. We aimed in this prospective observational study to evaluate the efficacy and safety of temporary SEMS placement in benign pyloric stenosis. Twenty-two patients with benign stenosis of the prepylorus, pylorus, and duodenal bulb were enrolled and underwent SEMS placement. We assessed symptom improvement, defined as an increase of at least 1 degree in the gastric-outlet-obstruction scoring system after stent insertion. No major complications were observed during the procedures. After stent placement, early symptom improvement was achieved in 18 of 22 patients (81.8%). During the follow-up period (mean 10.2 months), the stents remained in place successfully for 6 to 8 weeks in seven patients (31.8%). Among the 15 patients (62.5%) with stent migration, seven (46.6%) showed continued symptomatic improvement without recurrence of obstructive symptoms. Despite the symptomatic improvement, temporary SEMS placement is premature as an effective therapeutic tool for benign pyloric stenosis unless a novel stent is developed to prevent migration.

Expandable and retractable self-rolled structures based on metal/polymer thin film for flow sensing

Science.gov (United States)

Zhu, Jianzhong; White, Carl; Saadat, Mehdi; Bart-Smith, Hilary

2015-11-01

Most aquatic animals such as fish rely heavily on their ability of detect and respond to ambient flows in order to explore and inhabit various habitats or survive predator-prey encounters. Fish utilize neuromasts in their skin surface and lateral lines in their bodies to align themselves while swimming upstream for migration, avoid obstacles, reduce locomotion cost, and detect flow variations caused by potential predators. In this study, a thin film MEMS sensor analogous to a fish neuromast has been designed for flow sensing. Residual stress arises in many thin film materials during processing. Metal and polymer thin film materials with a significant difference in elastic modular were chosen to form a multiple-layer structure. Upon releasing, the structure rolls into a tube due to mechanical property mismatch. The self-rolled tube can expand or retract, depending on the existence of external force such as flow. An embedded strain sensor detects the deformation of the tube and hence senses the ambient flow. Numerical simulations were conducted to optimize the structural design. Experiments were performed in a flow tank to quantify the performance of the sensor. This research is supported by the Office of Naval Research under the MURI Grant N00014-14-1-0533.

Reocclusion after Self-Expandable Metallic Stent Placement for Relieving Malignant Colorectal Obstruction as a Palliative Treatment

Directory of Open Access Journals (Sweden)

Toshikatsu Nitta

2016-12-01

Full Text Available Self-expandable metallic stent (SEMS placement has been practiced in several hospitals in Japan, including ours, since January 2012. Here, we report the case of an 82-year-old Japanese man who presented to the hospital with a 1-week history of right hypochondrial pain. Computed tomography (CT findings indicated colorectal cancer. The laboratory findings on admission indicated severe anemia (red blood cell count, 426 × 104/μL; hemoglobin, 7.9 g/dL. We performed SEMS placement because the patient refused to undergo surgery. He did not attend any of the scheduled follow-up visits after SEMS placement. However, a year and a half after the SEMS placement, the patient attended the hospital because of difficulty in passing stool. A plain abdominal CT scan showed bowel reobstruction due to the ascending colon cancer after SEMS placement. We performed an emergency operation, ascending colostomy, on the same day. Colorectal stent placement may be a good treatment option for patients who refuse to undergo conventional therapeutic treatments or in those with unresectable colorectal cancer. Patients should be carefully followed up every few months after SEMS placement because of the risk of reocclusion.

Preoperative biliary decompression preceding pancreaticoduodenectomy with plastic or self-expandable metallic stent.

Science.gov (United States)

Haapamäki, C; Seppänen, H; Udd, M; Juuti, A; Halttunen, J; Kiviluoto, T; Sirén, J; Mustonen, H; Kylänpää, L

2015-06-01

The rainage (PBD) prior to pancreaticoduodenectomy (PD) is controversial. If PBD is required, large bore self-expandable metallic stents (SEMS) are thought to maintain better drainage and have fewer postoperative complications than plastic stents. The confirming evidence is scarce. The aim of the study was to compare outcomes of surgery in patients who underwent PBD with SEMS or plastic stents deployed at endoscopic retrograde cholangiopancreatography (ERCP). This is a retrospective study of 366 patients having had PD during 2000-2009. Preceding endoscopic PBD was performed in 191 patients and nine had had percutaneous transhepatic drainage (PTD). At the time of operation, 163 patients had a plastic stent and 28 had SEMS. Due to stent exchanges, 176 plastic stents and 29 SEMS were placed in all. The stent failure rate was 7.4% for plastic stents and 3.4% for SEMS (p = 0.697). A bilirubin level under 50 µmol/L was reached by 80% of the patients with plastic stents and by 61% of the patients with SEMS (p = 0.058). A postoperative infection complication and/or a pancreatic fistula was found in 26% while using plastic stents and in 25% using SEMS (p = 1.000). In unstented patients with biliary obstruction, the bile juice was sterile significantly more often than in endoscopically stented patients (100% vs 1%, p stented and unstented patients were compared regarding postoperative infection complications, there was no significant difference between the groups (p = 0.365). Plastic stents did not differ from SEMS regarding the stent failure rate, bilirubin level decrease, amount of bacteria in the bile juice, or postoperative complications when used for PBD. The significantly higher price of SEMS suggests their use in selected cases only. © The Finnish Surgical Society 2014.

Self-Expanding, Tough Biodegradable Elastomers for Wound Stasis

Science.gov (United States)

2015-08-06

the civilian setting, with no effective therapies available at point of injury. We previously reported that a self- expanding polyurethane foam...setting, with no effective therapies available at point of injury. We previously reported that a self-expanding polyurethane foam significantly...care in accor- dance with the Guide of the Care and Use of Laboratory Ani- mals (Health, 2011 #17). 2.2. Instrumentation and monitoring All swine (n

Use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats: six cases (2005-2007).

Science.gov (United States)

Berent, Allyson C; Weisse, Chick; Todd, Kimberly; Rondeau, Mark P; Reiter, Alexander M

2008-11-01

To determine outcome associated with use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats. Retrospective case series. 3 dogs and 3 cats. All 6 animals had severe inspiratory stertor at initial examination. Two animals had no orifice present at the stenosis. Nasopharyngeal stenosis was diagnosed and stent size determined by use of computed tomography. A percutaneous transluminal angioplasty balloon premounted with a balloon-expandable metallic stent was placed over a guidewire, advanced through the stenotic lesion under fluoroscopic and rhinoscopic guidance, and dilated to restore patency. All animals had immediate resolution of clinical signs after stent placement. The procedure took a median of 38 minutes (range, 22 to 70 minutes). One animal with a stenosis located far caudally needed the tip of the stent resected because of hairball entrapment and exaggerated swallowing. Both animals without an orifice in the stenosis had tissue in-growth requiring a covered stent. All animals were reexamined 6 to 12 weeks after treatment via rhinoscopy, radiography, computed tomography, or a combination of techniques. All animals lacked signs of discomfort; 5 of 6 were breathing normally 12 to 28 months after the procedure. Transnasal balloon-expandable metallic stent placement may represent a rapid, safe, noninvasive, and effective treatment in animals with nasopharyngeal stenosis. If the stenosis is extremely caudal in the nasopharynx, serial balloon dilatation might be considered prior to stent placement. A covered stent should be considered initially if the stenosis is completely closed.

[Complications and the management of fully covered retrievable metal stent placement in benign tracheal stenosis].

Science.gov (United States)

Wang, Zheng-yu; Wang, Yong-li; Chen, Guang-li; Liang, Xi-hong; Wang, Zhen-chang; Ma, Jian-zhong; Wu, Guang-zhong; Zhang, Xiao-ping

2012-11-01

To study complications and the management of the use of covered retrievable expandable metallic stents in the treatment of benign tracheal stenosis. Fully covered retrievable metal stents were placed in 21 patients with benign tracheal stenosis. Stent-related complications and the management were reviewed and analysed. Twenty-eight fully covered retrievable metallic stents were successfully placed fluoroscopically in 21 patients. Stents were removed 4 - 12 months [mean (5.5 ± 2.2) mouths] after placement in all patients. Stent-related complications included granulation tissue (n = 18), stent migration (n = 4), stent expectoration (n = 2), halitosis (n = 8), mucous retention (n = 21) and mucus plugging (n = 1). Granulation tissue was removed with a carbon dioxide laser in 2 patients. Stents were replaced for 2 times and 3 times respectively in 2 patients after stent migration and stent expectoration. An additional stent was placed in 2 patients after stent migration. Symptom of halitosis was relieved after prolonged course of systemic antibiotics treatment in 8 patients. Symptom of mucous retention was relieved with nebulized saline and N-acetylcysteine saline inhalation. Mucous plug was expelled after severe coughing after suctioning using an aspirator in one patient. There were statistically significant differences in stricture diameter, rank of tachypnea and pulmonary function (FEV(1)) in all 21 patients before stent insertion and after stents removal. No patient has experienced recurrence during the follow-up period of 1 - 36 months [mean (23.2 ± 8.0) months]. Fully covered retrievable metallic stent may be a safe and effective in benign tracheal stenosis. Stent-related complications may be effectively managed.

Malignant duodenal obstructions: palliative treatment with covered expandable nitinol stent

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Chul; Jung, Gyoo Sik; Lee, Sang Hee; Kim, Sung Min; Oh, Kyung Seung; Huh, Jin Do; Cho, Young Duk [College of Medicine, Kosin Univ, Pusan (Korea, Republic of); Song, Ho Young [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

2002-04-01

To evaluate the feasibility and clinical effectiveness of using a polyurethane-covered expandable nitinol stent in the palliative treatment of malignant duodenal obstruction. Under fluoroscopic guidance, a polyurethane-covered expandable nitinol stent was placed in 12 consecutive patients with malignant duodenal obstructions. All presented with severe nausea and recurrent vomiting. The underlying causes of obstruction were duodenal carcinoma (n=4), pancreatic carcinoma (n=4), gall bladder carcinoma (n=2), distal CBD carcinoma (n=1), and uterine cervical carcinoma (n=1). The sites of obstruction were part I (n=1), part II (n=8), and III (n=3). Due to pre-existing jaundice, eight patients with part II obstructions underwent biliary decompression prior to stent placement. An introducer sheath with a 6-mm outer diameter and stents 16 mm in diameter were employed, and to place the stent, and after-loading technique was used. Stent placement was technically successful in ten patients, and no procedural complications occuured. In one of two patients in whom there was technical failure, and in whom the obstructions were located in part III, the stent was placed transgastrically. Stent migration occurred in one patient four days after the procedure, and treatment involved the palcement of a second, uncovered, nitinol stent. After stent placement, symptoms improved in all patients. During follow-up, obstructive symptoms due to stent stenosis (n=1), colonic obstruction (n=1), and multiple small bowel obstruction (n=1) recurred in three patients. Two of these were treated by placing additional stents in the duodenum and colon, respectively. One of the eight patients in whom a stent was placed in the second portion of the duodenum developed jaundice. The patients died a mean 14 (median, 9) weeks after stent placement. The placement of a polyurethane-covered expandable nitinol stent seems to be technically feasible, safe and effective for the palliative treatment of malignant

Expanding Sex-Role Definitions by Self-Discovery.

Science.gov (United States)

Kahn, Sharon E.; Greenberg, Leslie S.

1980-01-01

Counselors who stimulate client self-discovery may help these clients experience undeveloped parts of themselves and expand their definitions of themselves and their sex-role possibilities. Stimulation methods actively involve clients in the exploration of sex-role concerns to change restrictive self-concepts. (Author)

Treatment of Esophageal Variceal Hemorrhage with Self-Expanding Metal Stents as a Rescue Maneuver in a Swiss Multicentric Cohort

Directory of Open Access Journals (Sweden)

Fabienne C. Fierz

2013-03-01

Full Text Available Acute esophageal variceal bleeding in patients with portal hypertension remains a complication with a high mortality today. In cases refractory to standard therapy including endoscopic band ligation and pharmacological therapy, traditionally balloon tamponade has been used as salvage therapy. However, these techniques show several important limitations. Self-expanding metal stents (SEMS have been proposed as an alternative rescue treatment. The use of variceal stenting in 7 patients with a total of 9 bleeding episodes in three different Swiss hospitals is demonstrated. While immediate bleeding control is achieved in a high percentage of cases, the 5-day and 6-week mortality rate remain high. Mortality is strongly influenced by the severity of the underlying liver disease. Accordingly, our data represent a high-risk patient collective. Thanks to their safety and easy handling, SEMS are an interesting alternative to balloon tamponade as a bridging intervention to definitive therapy including the pre-hospital setting.

Placement of a Newly Designed Y-Configured Bilateral Self-Expanding Metallic Stent for Hilar Biliary Obstruction: A Pilot Study.

Science.gov (United States)

Jiao, Dechao; Huang, Kai; Zhu, Ming; Wu, Gang; Ren, Jianzhuang; Wang, Yanli; Han, Xinwei

2017-01-01

Whether unilateral or bilateral drainage should be performed for malignant hilar biliary obstruction remains a matter of debate. Although a Y-stent with a central wide-open mesh facilitates bilateral stent placement, it has its own limitations. This study aims to evaluate the feasibility and efficacy of a newly designed Y-configured bilateral self-expanding metallic stent (SEMS) for the treatment of hilar biliary obstruction. In this retrospective study, 14 consecutive patients with unresectable malignant hilar biliary obstruction (Bismuth type II or higher), who underwent placement of a newly designed Y-configured bilateral SEMS for hilar biliary obstruction from April 2013 to March 2015, were included into this study. Data on technical success, clinical success, stent patency, complications and patient survival were collected. Technical and clinical success was 100 and 92.9 %, respectively. Mean serum bilirubin level was significantly decreased 1 month after stent placement (P hilar biliary obstruction using port docking deployment.

Malignant Gastroduodenal Obstruction: Treatment with Self-Expanding Uncovered Wallstent

International Nuclear Information System (INIS)

Gutzeit, Andreas; Binkert, Christoph A.; Schoch, Eric; Sautter, Thomas; Jost, Res; Zollikofer, Christoph L.

2009-01-01

Purpose: To retrospectively evaluate the clinical effectiveness of a self-expanding uncovered Wallstent in patients with malignant gastroduodenal obstruction. Materials and Methods: Under combined endoscopic and fluoroscopic guidance, 29 patients with a malignant gastroduodenal stenosis were treated with a self-expanding uncovered metallic Wallstent. A dysphagia score was assessed before and after the intervention to measure the success of this palliative therapy. The dysphagia score ranged between grade 0 to grade 4: grade 0 = able to tolerate solid food, grade 1 = able to tolerate soft food, grade 2 = able to tolerate thick liquids, grade 3 = able to tolerate water or clear fluids, and grade 4 = unable to tolerate anything perorally. Stent patency and patients survival rates were calculated. Results: The insertion of the gastroduodenal stent was technically successful in 28 patients (96.5%). After stenting, 25 patients (86.2%) showed clinical improvement by at least one score point. During follow-up, 22 (78.5%) of 28 patients showed no stent occlusion until death and did not have to undergo any further intervention. In six patients (20.6%), all of whom were treated with secondary stent insertions, occlusion with tumor ingrowth and/or overgrowth was observed after the intervention. The median period of primary stent patency in our study was 240 days. Conclusion: Placement of an uncovered Wallstent is clinically effective in patients with malignant gastroduodenal obstruction. Stent placement is associated with high technical success, good palliation effect, and high durability of stent function.

Self-expandable Metallic Stents Contribute to Reducing Perioperative Complications in Colorectal Cancer Patients with Acute Obstruction.

Science.gov (United States)

Furuke, Hirotaka; Komatsu, Shuhei; Ikeda, Jun; Tanaka, Sachie; Kumano, Tatsuya; Imura, Ken-Ichiro; Shimomura, Katsumi; Taniguchi, Fumihiro; Ueshima, Yasuo; Takashina, Ken-Ichiro; Lee, Chol Joo; Deguchi, Eiichi; Ikeda, Eito; Otsuji, Eigo; Shioaki, Yasuhiro

2018-03-01

The self-expandable metallic stent (SEMS) is an excellent non-invasive tool for emergent bowel obstruction. This study was designed to evaluate the clinical usefulness of the SEMS for avoiding perioperative complications. We analyzed a total of 47 consecutive patients who had a bowel obstruction due to colorectal cancer at initial diagnosis between 2012 and 2017 from hospital records. Perioperative complications occurred in 30% (14/47) of patients. Univariate and multivariate logistic regression analyses identified an age of more than 75 years [p=0.037, OR=6.84 (95% CI=1.11-41.6)] and the absence of an SEMS treatment [p=0.028, OR=18.5 (95% CI=1.36-250.0)] as independent risk factors for perioperative complications. Pneumonia (12.7% (6/47)) was the most common complication. There were no pneumonia patients (0% (0/15)) who were treated with the SEMS. In contrast to patients with the non-SEMS treatment, 18.7% (6/32) of all patients and 35.7% (5/14) of elderly patients had pneumonia. The SEMS is a safe and effective treatment for avoiding perioperative complications, particularly pneumonia, and may be a crucial strategy in elderly patients with acute obstruction due to colorectal cancer. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

SU-E-T-115: Dose Perturbation Study of Self-Expandable Metal and Polyester Esophageal Stents in Proton Therapy Beams

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Lee, S; Li, Z [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Jalaj, S; McGaw, C; B K, John; J S, Scolapio; J C, Munoz [Division of Gastoenterology, Department of Medicine, University of Florida, Jacksonville, FL (United States)

2014-06-01

Purpose: This work investigates dose perturbations due to Self-expandable metal and polyester esophageal stents undergoing proton radiotherapy for esophageal cancer. Methods: Five commercially available esophageal stents made of nitinol (Evolution, Wallflex and Ultraflex), stainless steel (Z-Stent) and polyester (Polyflex) were tested. Radiochromic film (GafChromic EBT3 film, Ashland, Covington, KY) wrapped around a stent and a 12cc syringe was irradiated with 2CGE (Cobalt Gray Equivalent) of proton beam in a custom fabricated acrylic phantom. An air-hollow syringe simulates the esophagus. Results: The Z-stent created the largest dose perturbations ranges from -14.5% to 6.1% due to the steel composition. The WallFlex, Evolution and Ultraflex stents produced the dose perturbation ranges of (−9.2%∼8.6%), (−6.8%∼5.7%) and (−6.2%∼6.2%), respectively. The PolyFlex stent contains the radiopaque tungsten markers located top, middle and bottom portions. When the focal cold spots induced by the markers were excluded in the analysis, the dose perturbation range was changed from (−11.6%∼6.4%) to (−0.6%∼5.0%). Conclusion: The magnitude of dose perturbation is related to material of a metallic stent. The non-metallic stent such as PolyFlex shows relatively lower dose perturbation than metallic stents except a radiopaque marker region. Overall Evolution and Ultraflex stent appear to be less dose perturbations. The largest dose perturbations (cold spots) were located at both edges of stents in distal area for the single proton beam irradiation study. The analysis of more than two proton beam which is more typical clinical beam arrangement would be necessary to minimize the doe perturbation effect in proton ratiotherapy.

Outcomes of the Use of Fully Covered Esophageal Self-Expandable Stent in the Management of Colorectal Anastomotic Strictures and Leaks

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Chad J. Cooper

2014-01-01

Full Text Available Introduction. Colorectal anastomotic leak or stricture is a dreaded complication leading to significant morbidity and mortality. The novel use of self-expandable metal stents (SEMS in the management of postoperative colorectal anastomotic leaks or strictures can avoid surgical reintervention. Methods. Retrospective study with particular attention to the indications, operative or postoperative complications, and clinical outcomes of SEMS placement for patients with either a colorectal anastomotic stricture or leak. Results. Eight patients had SEMS (WallFlex stent for the management of postoperative colorectal anastomotic leak or stricture. Five had a colorectal anastomotic stricture and 3 had a colorectal anastomotic leak. Complete resolution of the anastomotic stricture or leak was achieved in all patients. Three had recurrence of the anastomotic stricture on 3-month flexible sigmoidoscopy follow-up after the initial stent was removed. Two of these patients had a stricture that was technically too difficult to place another stent. Stent migration was noted in 2 patients, one at day 3 and the other at day 14 after stent placement that required a larger 23 mm stent to be placed. Conclusions. The use of SEMS in the management of colorectal anastomotic leaks or strictures is feasible and is associated with high technical and clinical success rate.

Self-expandable metallic stent placement plus laparoscopy for acute malignant colorectal obstruction.

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Zhou, Jia-Min; Yao, Li-Qing; Xu, Jian-Min; Xu, Mei-Dong; Zhou, Ping-Hong; Chen, Wei-Feng; Shi, Qiang; Ren, Zhong; Chen, Tao; Zhong, Yun-Shi

2013-09-07

To investigate the clinical advantages of the stent-laparoscopy approach to treat colorectal cancer (CRC) patients with acute colorectal obstruction (ACO). From April 2008 to April 2012, surgery-related parameters, complications, overall survival (OS), and disease-free survival (DFS) of 74 consecutive patients with left-sided CRC presented with ACO who underwent self-expandable metallic stent (SEMS) placement followed by one-stage open (n = 58) or laparoscopic resection (n = 16) were evaluated retrospectively. The stent-laparoscopy group was also compared with a control group of 96 CRC patients who underwent regular laparoscopy without ACO between January 2010 and December 2011 to explore whether SEMS placement influenced the laparoscopic procedure or reduced long-term survival by influencing CRC oncological characteristics. The characteristics of patients among these groups were comparable. The rate of conversion to open surgery was 12.5% in the stent-laparoscopy group. Bowel function recovery and postoperative hospital stay were significantly shorter (3.3 ± 0.9 d vs 4.2 ± 1.5 d and 6.7 ± 1.1 d vs 9.5 ± 6.7 d, P = 0.016 and P = 0.005), and surgical time was significantly longer (152.1 ± 44.4 min vs 127.4 ± 38.4 min, P = 0.045) in the stent-laparoscopy group than in the stent-open group. Surgery-related complications and the rate of admission to the intensive care unit were lower in the stent-laparoscopy group. There were no significant differences in the interval between stenting and surgery, intraoperative blood loss, OS, and DFS between the two stent groups. Compared with those in the stent-laparoscopy group, all surgery-related parameters, complications, OS, and DFS in the control group were comparable. The stent-laparoscopy approach is a feasible, rapid, and minimally invasive option for patients with ACO caused by left-sided CRC and can achieve a favorable long-term prognosis.

Outcomes of second self-expandable metallic stent insertion for malignant gastric outlet obstruction.

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Kim, Chan Gyoo; Choi, Il Ju; Lee, Jong Yeul; Cho, Soo-Jeong; Kim, Soo Jin; Kim, Mi-Jung; Park, Sook Ryun; Park, Young Lee

2014-01-01

Self-expandable metallic stents are used widely to relieve malignant gastric outlet obstruction (GOO). However, restenosis or migration of first stents is a frequent complication. The purpose of this retrospective cohort study was to evaluate the effectiveness of second stents as an approach to manage failure of first stents in patients with malignant GOO. A total of 222 patients with gastric cancer received first stents due to inoperable GOO at National Cancer Center in Korea between January 2008 and June 2011. Monthly follow-up interviews were performed, and second stents (stent-in-stent or stent-after-migration) were inserted in 59 patients by June 2012. Technical and clinical successes and long-term complications were evaluated. The technical and immediate clinical success rates were 98.3 % (58/59) and 91.5 % (54/59), respectively. Patients who received a second stent due to late complications involving the first stent (migration, restenosis, and fracture) showed a higher clinical success rate (95.8 % [46/48]) than patients who received a second stent due to immediate clinical failure of the first stent (72.7 % [8/11], p = 0.04). The immediate clinical success rate of stent-after-migration (100 % [11/11]) was not different from that of stent-in-stent (89.6 % [43/48], p = 1.0). The stent dysfunction rate of stent-after-migration (27.3 % [3/11]) also was similar to that of stent-in-stent (29.2 % [14/48], p = 1.0). The median patencies of stent-in-stent and stent-after-migration were 27.4 and 58.4 weeks, respectively (p = 0.177). There were no significant prognostic factors for patency of second stents. Insertion of a second stent is effective for treating the first-stent failure in gastric cancer patients with GOO, especially if the immediate outcome of the first stent was successful.

Mechanical characteristics of self-expandable metallic stents: in vitro study with three types of stress

International Nuclear Information System (INIS)

Lee, Byung Hee; Kim, Kie Hwan; Chin, Soo Yil

1998-01-01

To obtain objective and comparable data for mechanical characteristics of self-expandable metallic stents widely used in the treatment of biliary obstruction. The stents tested were the 6 and 8 mm-band Hanaro spiral stent, Gianturco-Rosch Z stent, Wallstent, Ultraflex stent, and Memotherm stent. Each was subjected to three types of load:point, area, and circular. We analyzed their mechanical characteristics (resistance force, expansile force, and elasticity) according to these three types of stress. With regard to point loads, the Memotherm stent showed the highest resistance force and expansile force. The 8 mm-band Hanaro stent showed the lowest resistance force and the Gianturco-Rosch Z stent and Ultraflex stent showed lower expansile force. With regard to area loads, the Ultraflex stent showed the highest resistance force. The 6 mm-band Hanaro stent, Gianturco-Rosch Z stent, and Ultraflex stent showed higher expansile force. The 8 mm-band Hanaro stent showed the lowest value in both resistance force and expansile force. For circular loads, the Memotherm stent showed the highest resistance force and the Ultraflex stent and Wallstent showed lower value. Under all types of stress, the Hanaro stent and Memotherm stent were completely elastic, and the Ultraflex stent and Wallstent showed a wide gap between resistance force and expansile force. In clinical practice, awareness of the mechanical characteristics of each stent might help in choosing the one which is most suitable, according to type of biliary obstruction. =20

Mechanical characteristics of self-expandable metallic stents: in vitro study with three types of stress

Energy Technology Data Exchange (ETDEWEB)

Lee, Byung Hee; Kim, Kie Hwan; Chin, Soo Yil [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1998-09-01

To obtain objective and comparable data for mechanical characteristics of self-expandable metallic stents widely used in the treatment of biliary obstruction. The stents tested were the 6 and 8 mm-band Hanaro spiral stent, Gianturco-Rosch Z stent, Wallstent, Ultraflex stent, and Memotherm stent. Each was subjected to three types of load:point, area, and circular. We analyzed their mechanical characteristics (resistance force, expansile force, and elasticity) according to these three types of stress. With regard to point loads, the Memotherm stent showed the highest resistance force and expansile force. The 8 mm-band Hanaro stent showed the lowest resistance force and the Gianturco-Rosch Z stent and Ultraflex stent showed lower expansile force. With regard to area loads, the Ultraflex stent showed the highest resistance force. The 6 mm-band Hanaro stent, Gianturco-Rosch Z stent, and Ultraflex stent showed higher expansile force. The 8 mm-band Hanaro stent showed the lowest value in both resistance force and expansile force. For circular loads, the Memotherm stent showed the highest resistance force and the Ultraflex stent and Wallstent showed lower value. Under all types of stress, the Hanaro stent and Memotherm stent were completely elastic, and the Ultraflex stent and Wallstent showed a wide gap between resistance force and expansile force. In clinical practice, awareness of the mechanical characteristics of each stent might help in choosing the one which is most suitable, according to type of biliary obstruction. =20.

Basic Knowledge about Metal Stent Development

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Seok Jeong

2016-03-01

Full Text Available Biliary self-expandable metal stents (SEMS, a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

Recent Advancements in Self-Healing Metallic Materials and Self-Healing Metal Matrix Composites

Science.gov (United States)

Kilicli, Volkan; Yan, Xiaojun; Salowitz, Nathan; Rohatgi, Pradeep K.

2018-04-01

Engineered self-healing materials inspired by natural biological organisms that can repair damage are receiving increasing interest in recent years. Most studies have been focused on self-healing polymers, concretes, and ceramics. Self-healing metallic materials pose challenges due to the high temperatures used in manufacturing and the chemistries involved. This article summarizes and evaluates the self-healing mechanisms used in metallic materials and reviews recent studies into self-healing in aluminum, zinc, and Sn-Bi alloys. Generalizations about the various classifications are drawn from the review highlighting major hurdles in the widespread practical application of metallic self-healing materials, as well as the potential directions for future studies.

Influence of paclitaxel-eluting expandable metallic stent on tissue hyperplasia: an experimental study in a canine tracheal model

International Nuclear Information System (INIS)

Shin, Ji Hoon; Kim, Jung Sun; Kim, Tae Hyung; Kim, Eun Young; Choi, Won Chan; Woo, Chul Woong; Di, Zhenhai; Song, Ho Young; Yuk, Soon Hong; Lee, Yong Seok

2005-01-01

To evaluate the efficacy of a paclitaxel-eluting expandable metallic stent in reducing tissue hyperplasia following stent placement in a canine tracheal model. Nine paclitaxel-eluting stents (drug stent, DS) consisting of a proximal bare part and a distal polyurethane-covered part were placed in the trachea of nine dogs and nine control stents (control stent, CS) were placed in the other nine dogs. The dogs were scheduled to be sacrificed 12 weeks after stent placement. Gross and histological factors, such as epithelial erosion/ulcer, granulation tissue thickness and inflammatory cell infiltration were evaluated after each dog was sacrificed. There were no procedure-related complications or malpositioning of any of the stents. One CS migrated less than eight weeks following stent placement. Four dogs (one DS and three CS dogs) died between three and five weeks following stent placement. Therefore, pathologic specimens were obtained from eight DS and five CS dogs. Epithelial erosion/ulcer or inflammatory cell infiltration was slightly more prominent in the DS cases than in the CS cases, in both the bare part and the covered part. However, the data was not statistically significant. Granulation tissue thickness was lower in the DS cases than in the CS cases in both the bare part (mean, 3.63-mm vs. 4.37-mm) and the covered part (mean, 1.75-mm vs. 2,78 mm), but the data was also statistically insignificant. Although the data was not statistically significant, placement of paclitaxel-eluting expandable metallic stent demonstrates a tendency toward a decrease in granulation tissue thickness in canine tracheal models

Influence of paclitaxel-eluting expandable metallic stent on tissue hyperplasia: an experimental study in a canine tracheal model

Energy Technology Data Exchange (ETDEWEB)

Shin, Ji Hoon; Kim, Jung Sun; Kim, Tae Hyung; Kim, Eun Young; Choi, Won Chan; Woo, Chul Woong; Di, Zhenhai; Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Yuk, Soon Hong [Hannam University, College of Engineering, Daejeon (Korea, Republic of); Lee, Yong Seok [Wonkwang University College of Medicine, Iksan (Korea, Republic of)

2005-07-15

To evaluate the efficacy of a paclitaxel-eluting expandable metallic stent in reducing tissue hyperplasia following stent placement in a canine tracheal model. Nine paclitaxel-eluting stents (drug stent, DS) consisting of a proximal bare part and a distal polyurethane-covered part were placed in the trachea of nine dogs and nine control stents (control stent, CS) were placed in the other nine dogs. The dogs were scheduled to be sacrificed 12 weeks after stent placement. Gross and histological factors, such as epithelial erosion/ulcer, granulation tissue thickness and inflammatory cell infiltration were evaluated after each dog was sacrificed. There were no procedure-related complications or malpositioning of any of the stents. One CS migrated less than eight weeks following stent placement. Four dogs (one DS and three CS dogs) died between three and five weeks following stent placement. Therefore, pathologic specimens were obtained from eight DS and five CS dogs. Epithelial erosion/ulcer or inflammatory cell infiltration was slightly more prominent in the DS cases than in the CS cases, in both the bare part and the covered part. However, the data was not statistically significant. Granulation tissue thickness was lower in the DS cases than in the CS cases in both the bare part (mean, 3.63-mm vs. 4.37-mm) and the covered part (mean, 1.75-mm vs. 2,78 mm), but the data was also statistically insignificant. Although the data was not statistically significant, placement of paclitaxel-eluting expandable metallic stent demonstrates a tendency toward a decrease in granulation tissue thickness in canine tracheal models.

An approach to tracheostomy in a patient with an expandable metallic tracheal stent.

Science.gov (United States)

Madden, Brendan P; Sheth, Abhijat

2005-09-01

With increasing use of expandable metallic stents to manage patients with a variety of endobronchial pathologies, some will have a subsequent need for tracheostomy insertion. We describe a successful technique to insert a tracheostomy using rigid and fibre-optic bronchoscopy in a patient who had an 8 cm expandable metallic tracheal stent deployed previously on account of tracheomalacia.

Self-expandable metallic stents vs. plastic stents for endoscopic biliary drainage in hepatocellular carcinoma.

Science.gov (United States)

Chung, Kwang Hyun; Lee, Sang Hyub; Park, Jin Myung; Lee, Jae Min; Ahn, Dong-Won; Ryu, Ji Kon; Kim, Yong-Tae

2015-06-01

The patency of self-expandable metallic stents (SEMS) is known to be better than plastic stents in the palliation of malignant biliary obstruction. However, data are scarce for obstructive jaundice caused by hepatocellular carcinoma (HCC). This study aimed to compare SEMSs and plastic stents for the palliation of obstructive jaundice in unresectable HCC. A total of 96 patients who underwent endoscopic retrograde biliary drainage with SEMSs or plastic stents were included in this retrospective analysis. The rate of successful biliary drainage, adverse events, stent patency duration, and patient survival were compared between the SEMS (n = 36) and plastic stent (n = 60) groups. The rate of successful biliary drainage was similar between the SEMS and plastic stent groups (25/36 [69.4 %] vs. 39/60 [65.0 %]; P = 0.655). Adverse events occurred in 6 patients (16.7 %) in the SEMS group and 13 patients (21.7 %) in the plastic stent group (P = 0.552). The median patency duration was also similar between the two groups (60 vs. 68 days; P = 0.396). The median patient survival was longer in the plastic stent group than in the SEMS group (123 vs. 48 days; P = 0.005). SEMSs were not superior to plastic stents for the palliation of malignant biliary obstruction in HCC with regard to successful drainage, stent patency, and adverse events. Patient survival was better in the plastic stent group. Given the lower cost, plastic stents could be a favorable option for malignant biliary obstruction caused by HCC. © Georg Thieme Verlag KG Stuttgart · New York.

Self-expanding metal mesh stents and laser therapy: a complementary approach for the palliation of malignant dysphagia

Science.gov (United States)

Madhotra, Ravi; Raouf, A.; Sturgess, R.; Krasner, Neville

1997-12-01

Re-establishment of the oesophageal lumen is the main focus of care in patients with inoperable oesophageal carcinomas. The self-expanding metal mesh stents (MMS) are increasingly being used. 51 patients aged 44 - 89 with inoperable oesophago-gastric carcinomas were intubated with MMS. 18 of these patients had endoscopic laser therapy (ELT) as primary palliation. 25 patients required follow-up endoscopy at variable intervals after stent insertion. 17 patients were found to have significant tumor growth (9), overgrowth (4) and both (4). All these patients were treated with Nd:YAG or diode laser for maintenance of satisfactory swallowing. 4 patients being treated with Nd:YAG laser developed deformity of MMS. This complication was not encountered with diode laser. The reblockage of MMS due to ingrowth or overgrowth of tumor is a not uncommon complication. The timing of the stent insertion should be carefully chosen since the longer the stent is in situ, the greater is the likelihood of tumor ingrowth or overgrowth. ELT can effectively deal with tumor ingrowth and overgrowth. Nd:YAG laser can cause melting of MMS. Overall the combination of ELT and MMS may offer the best palliation, particularly when patient survival of several months is anticipated.

Clinical Impact of Prophylactic Antibiotic Treatment for Self-Expandable Metallic Stent Insertion in Patients with Malignant Colorectal Obstruction

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Jong-Sun Kim

2015-01-01

Full Text Available Purpose. The aim of this study was to determine the efficacy of prophylactic antibiotics (PA for reducing the infectious complications and the potential risk factors responsible for the infectious complications after stent insertion for malignant colorectal obstruction. Methods. We performed a retrospective review of 224 patients who underwent self-expandable metallic stent (SEMS insertion for malignant colorectal obstruction from May 2004 to December 2012. Results. There were 145 patients in the PA group and 79 in non-PA group. The CRP level in PA group was significantly higher than that in non-PA. Abdominal tenderness and mechanical ileus were significantly more frequent in PA group than those in non-PA. The frequency of post-SEMS insertion fever, systemic inflammatory response syndrome (SIRS, and bacteremia was not significantly different between PA and non-PA groups. In multivariate analysis, the CRP level was risk factor related to post-SEMS insertion SIRS. However, in propensity score matching analysis, there was no independent risk factor related to post-SEMS insertion fever, SIRS, and bacteremia. Conclusion. The use of PA in patients with malignant colorectal obstruction may be not effective to prevent the development of infectious complications after SEMS insertion.

Customized Hinged Covered Metallic Stents for the Treatment of Benign Main Bronchial Stenosis.

Science.gov (United States)

Han, Xinwei; Al-Tariq, Quazi; Zhao, Yanle; Li, Lei; Cheng, Zhe; Wang, Huaqi; Liu, Chao; Jiao, Dechao; Wu, Gang

2017-08-01

To address the limitations of silicone stents, we designed a hinged self-expandable covered metallic stent. The aim of this study was to evaluate the safety and efficacy of the customized stents in clinical applications. This was a retrospective analysis. Under conscious sedation and local anesthesia, the stents were implanted or removed by interventional radiologists, with fluoroscopic guidance. Of 24 patients with benign main bronchial stenosis, stents were successfully placed in 21 (87.5%). The low-pressure balloon before dilation failed in 1 case (4.17%) of left main bronchial cicatricial stenosis. In 2 other cases (8.33%), stent placement was abandoned. Stents were successfully removed between 29 and 103 days after the procedure. After stent removal, the follow-up lasted for at least 12 months. Restenosis occurred only in 1 case (4.55%) owing to bronchial collapse 3 days after stent removal. Dyspnea occurred in another case (4.55%) at 2 months after retrieval; recurrence was confirmed using bronchoscopy, leading to a left pneumonectomy. The described procedure is safe and easy to be performed and avoids the use of intubation, bronchoscopy, and general anesthesia. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Safety and benefits of self-expandable metallic stents with chemotherapy for malignant gastric outlet obstruction.

Science.gov (United States)

Miyabe, Katsuyuki; Hayashi, Kazuki; Nakazawa, Takahiro; Sano, Hitoshi; Yamada, Tomonori; Takada, Hiroki; Naitoh, Itaru; Shimizu, Shuya; Kondo, Hiromu; Nishi, Yuji; Yoshida, Michihiro; Umemura, Shuichiro; Hori, Yasuki; Kato, Akihisa; Ohara, Hirotaka; Joh, Takashi

2015-07-01

The influence of chemotherapy on placement of self-expandable metallic stents (SEMS) for malignant gastric outlet obstruction (MGOO) has not been evaluated extensively. We investigated the influence of chemotherapy on the clinical outcomes of SEMS placement for MGOO. A total of 152 cancer patients with MGOO from a university hospital and affiliate hospitals were included. The patients were classified according to chemotherapy status and evaluated for palliative efficacy and safety of SEMS placement. Technical success rate, time to oral intake, and parameters indicating improvement of physical condition did not differ between the with- and without-chemotherapy groups after stent placement. Re-intervention and stent migration were significantly more frequent in the with-chemotherapy group than in the without-chemotherapy group after stent placement (re-intervention, 32.4% vs 7.8%, P = 0.0005; stent migration, 13.5% vs 1.7%, P = 0.0097). The frequency of adverse events did not differ between the with- and without-chemotherapy groups. Although chemotherapy after stent placement was an independent predictive factor for shortening the stent patency period (hazard ratio [HR], 3.10; P = 0.0264), the use of additional stents facilitated uneventful recovery and further prolonged survival time (HR, 0.60; P = 0.0132). Various cancer patients with MGOO can undergo SEMS placement safely regardless of chemotherapy, and concurrent chemotherapy after stent placement can prolong survival time, although re-intervention and stent migration may be increased. © 2015 The Authors. Digestive Endoscopy © 2015 Japan Gastroenterological Endoscopy Society.

A prospective group sequential study evaluating a new type of fully covered self-expandable metal stent for the treatment of benign biliary strictures (with video).

Science.gov (United States)

Poley, Jan-Werner; Cahen, Djuna L; Metselaar, Herold J; van Buuren, Henk R; Kazemier, Geert; van Eijck, Casper H J; Haringsma, Jelle; Kuipers, Ernst J; Bruno, Marco J

2012-04-01

Fully-covered self expandable metal stents (fcSEMSs) are an alternative to progressive plastic stenting for the treatment of benign biliary strictures (BBS) with the prospect of a higher treatment efficacy and the need for fewer ERCPs, thereby reducing the burden for patients and possibly costs. Key to this novel treatment is safe stent removal. To investigate the feasibility and safety of stent removal of a fcSEMS with a proximal retrieval lasso: a long wire thread integrated in the proximal ends of the wire mesh that hangs freely in the stent lumen. Pulling it enables gradual removal of the stent inside-out. A secondary aim was success of stricture resolution. Non-randomized, prospective follow-up study with 3 sequential cohorts of 8 patients with BBS. Academic tertiary referral center. Eligible patients had strictures either postsurgical (post-cholecystectomy (LCx) or liver transplantation (OLT)), due to chronic pancreatitis (CP), or papillary stenosis (PF). Strictures had to be located at least 2 cm below the liver hilum. All patients had one plastic stent in situ across the stricture and had not undergone previous treatment with either multiple plastic stents or fcSEMS. The first cohort of patients underwent stent placement for 2 months, followed by 3 months if the stricture had not resolved. The second and third cohort started with 3 months and 4 months, respectively, both followed by another 4 months if indicated. Treatment success was defined by stricture resolution at cholangiography, the ability to pass an inflated extraction balloon and clinical follow-up (at least 6 months). safety of stent removal. Secondary outcomes were complications and successful stricture resolution. A total of 23 patients (11 female; 20-67 yrs) were eligible for final analysis. One patient developed a malignant neuroendocrine tumor in the setting of CP. Strictures were caused by CP (13), OLT (6), LCx (3) and PF (1). In total 39 fcSEMS were placed and removed. Removals were easy

Self-expanding Y stents in the treatment of central airway stenosis: a retrospective analysis.

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Gompelmann, Daniela; Eberhardt, Ralf; Schuhmann, Maren; Heussel, Claus P; Herth, Felix J F

2013-10-01

Central airway obstruction (CAO) is a life-threatening situation. Stent insertion re-establishes patency of the central airways. Self-expanding metallic Y stents have been available since 2005, widening the spectrum of interventional bronchoscopic techniques. Retrospective analysis of all patients treated for CAO with a self-expanding metallic Y stent at the Thoraxklinik Heidelberg between May 2005 and January 2009. A total of 43 patients aged 26-81 had a metallic Y stent inserted endoscopically for the treatment of CAO; 39 of these patients (90.7%) had CAO due to malignant disease, four patients (9.3%) due to benign disease. In all 43 patients, the Y stent was deployed without any complications. A longitudinal follow up was possible in 32 of the 43 patients. The stents remained in situ for an average of 107.1 days (range 1-640 days). In 29 patients with malignant CAO the stenosis was successfully overcome with a Y stent; 11 of these patients died within 6 weeks following stent insertion. On follow up the remaining 18 patients showed immediate improvement of dyspnoea. Eight out of the 18 patients (44.4%) tolerated the stent without problems, two (11.1%) required further stenting, six (33.3%) had complications such as increased secretions, cough, dyspnoea or granulation tissue formation. The stent was removed in one patient (5.6%) due to increased secretions, and in another (5.6%) as the stent was no longer required due to successful tumour-specific therapy. Placement of Y stents in symptomatic CAO allows for quick relief of symptoms. Severe complications are rare. Stent removal is possible after successful treatment of the primary tumour. However, the prognostic indicator for survival is the underlying malignancy.

Covering a Crucible with Metal Containing Channels

Science.gov (United States)

Grugel, Richard N.

2006-01-01

In a procedure that partly resembles the lost-wax casting process, a crucible made of a brittle material (ceramic, quartz, or glass) is covered with a layer of metal containing channels. The metal cover and the channels can serve any or all of several purposes, depending upon the application: Typically, the metal would serve at least partly to reinforce the crucible. The channels could be used as passages for narrow objects that could include thermocouples and heat-transfer strips. Alternatively or in addition, channels could be used as flow paths for liquid or gaseous coolants and could be positioned and oriented for position- or direction-selective cooling. In some cases, the channels could be filled with known gases and sealed so that failure of the crucibles could be indicated by instruments that detect the gases. The process consists of three main steps. In the first step, a pattern defining the channels is formed by wrapping or depositing a material in the desired channel pattern on the outer surface of the crucible. The pattern material can be a plastic, wax, low-ash fibrous material, a soluble material, or other suitable material that can subsequently be removed easily. In a proof-of-concept demonstration (see figure), the crucible was an alumina cylinder and the mold material was plastic tie-down tape. In the second step, the patterned crucible is coated with metal. In one variation of the second step, a very thin layer containing or consisting of an electrically conductive material (e.g., gold, silver, or carbon) is painted or otherwise deposited on the mold-covered crucible, then the covering metal required for the specific application is electrodeposited on the very thin conducting layer. In another variation of the second step, the metal coat is formed by chemical vapor deposition. In the proof-of-concept demonstration, a layer of nickel 0.003 in. ( 0.08 mm) thick was electrodeposited. In the third step, the patterned material is removed. This is

Clinical application of self-expanding metallic stent in the management of acute left-sided colorectal malignant obstruction

Institute of Scientific and Technical Information of China (English)

You-Ben Fan; Ying-Sheng Cheng; Ni-Wei Chen; Hui-Min Xu; Zhe Yang; Yue Wang; Yu-Yao Huang; Qi Zheng

2006-01-01

AIM: To summarize our experience with the application of self-expanding metallic stent (SEMS) in the management of acute left-sided colorectal malignant obstruction.METHODS: A retrospective chart review of all patients undergoing placement of SEMS between April 2000 and January 2004 was performed.RESULTS: Insertion of SEMS was attempted in 26patients under fluoroscopic guidance with occasional endoscopic assistance. The sites of lesions were located in splenic flexure of two patients, left colon of seven patients, sigmoid colon of eight patients and rectum of nine patients. The intended uses of SEMS were for palliation in 7 patients and as a bridge to elective surgery in 19 patients. In the latter group, placement of SEMS allowed for preoperative systemic and bowel preparation and the following one-stage anastomosis. Successful stent placement was achieved in 22 (85%) of the 26patients. The clinical bowel obstruction resolved 24 hours after successful stent placement in 21 (95%) patients.Three SEMS-related minor complications occurred, two stents migrated and one caused anal pain.CONCLUSION: SEMS represents an effective and safe tool in the management of acute malignant colorectal obstruction. As a bridge to surgery, SEMS can provide time for systematic support and bowel preparation and obviate the need for fecal diversion or on-table lavage.As a palliative measure, SEMS can eliminate the need for emergent colostomy.

Outcomes and complications of self-expanding metal stent placement for malignant colonic obstruction in a single-center study.

Science.gov (United States)

Stankiewicz, Rafał; Kozieł, Sławomir; Pertkiewicz, Jan; Zieniewicz, Krzysztof

2018-03-01

Approximately 20% of cases of colorectal cancer are accompanied by acute colonic obstruction. While emergency colonic surgery is associated with high mortality and morbidity rates, placement of a self-expanding metal stent (SEMS) has been suggested as an alternative method. The SEMS placement can serve as either a definitive treatment in palliative cases or a bridge to surgery. To summarize the experience of our center in the treatment of malignant colonic obstruction using SEMS placement. A retrospective review was conducted of all patients who underwent a SEMS placement for colorectal stricture in the study period. The procedures were performed under fluoroscopic guidance with colonoscopic assistance, and uncovered stents were used in all patients. The study population consisted of 28 patients treated with SEMS placement due to malignant colonic obstruction. The majority of procedures were performed with palliative intent. The overall technical success rate was 96.5%, and clinical success was achieved in all of the successfully placed SEMSs. One fatal complication due to colonic perforation occurred. In the bridge-to-surgery group, all patients experienced tumor resection with no stoma creation. The SEMS placement is an optimal treatment in the vast majority of acute colonic obstruction cases. Due to the possibility of potentially fatal complications, SEMS procedures should be performed by proficient endoscopists.

Hepatocellular Carcinoma Complicated by Gastroduodenal Obstruction: Palliative Treatment with Metallic Stent Placement

Energy Technology Data Exchange (ETDEWEB)

Lee, Ye Jin; Kim, Jin Hyoung, E-mail: m1fenew@daum.net; Song, Ho-Young; Park, Jung-Hoon; Na, Han Kyu; Kim, Pyeong Hwa; Fan, Yong [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of)

2012-10-15

Purpose: To evaluate the clinical effectiveness of self-expandable metallic stents in seven patients with malignant gastroduodenal obstruction caused by inoperable hepatocellular carcinoma (HCC). Methods: Seven patients with gastroduodenal obstruction caused by advanced HCC underwent metallic stent placement from 2003 to 2010. These patients had total dysphagia (n = 5) or were able to eat only liquids (n = 2) before stent placement. Patients had Eastern Cooperative Oncology Group performance scores of 2 or 3, and Child-Pugh classification B or C. Results: Stent placement was technically successful in all seven patients (100%) and clinically successful in six (86%). Five patients could eat a soft diet, and one patient tolerated regular diet after stent placement. Stent-related obstructive jaundice occurred in one patient. One patient had hematemesis 11 days after stent placement. Overall mean survival was 51 days (range, 10-119 days). Stent patency was preserved in six patients with clinical success until death. Conclusion: Placement of a covered self-expandable metallic stent may offer good palliation in patients with gastroduodenal obstruction due to advanced HCC.

Hepatocellular Carcinoma Complicated by Gastroduodenal Obstruction: Palliative Treatment with Metallic Stent Placement

International Nuclear Information System (INIS)

Lee, Ye Jin; Kim, Jin Hyoung; Song, Ho-Young; Park, Jung-Hoon; Na, Han Kyu; Kim, Pyeong Hwa; Fan, Yong

2012-01-01

Purpose: To evaluate the clinical effectiveness of self-expandable metallic stents in seven patients with malignant gastroduodenal obstruction caused by inoperable hepatocellular carcinoma (HCC). Methods: Seven patients with gastroduodenal obstruction caused by advanced HCC underwent metallic stent placement from 2003 to 2010. These patients had total dysphagia (n = 5) or were able to eat only liquids (n = 2) before stent placement. Patients had Eastern Cooperative Oncology Group performance scores of 2 or 3, and Child-Pugh classification B or C. Results: Stent placement was technically successful in all seven patients (100%) and clinically successful in six (86%). Five patients could eat a soft diet, and one patient tolerated regular diet after stent placement. Stent-related obstructive jaundice occurred in one patient. One patient had hematemesis 11 days after stent placement. Overall mean survival was 51 days (range, 10–119 days). Stent patency was preserved in six patients with clinical success until death. Conclusion: Placement of a covered self-expandable metallic stent may offer good palliation in patients with gastroduodenal obstruction due to advanced HCC.

Expanding hollow metal rings

Science.gov (United States)

Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

2009-03-17

A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

Subclinical leaflet thickening and stent frame geometry in self-expanding transcatheter heart valves

DEFF Research Database (Denmark)

Fuchs, Andreas; De Backer, Ole; Brooks, Matthew

2017-01-01

AIMS: This study aimed to assess the potential relationship between subclinical leaflet thickening and stent frame geometry in patients who underwent aortic valve replacement with a self-expanding transcatheter heart valve (THV). METHODS AND RESULTS: Seventy-five patients with a self-expanding THV....... CONCLUSIONS: Regional THV stent frame underexpansion is associated with an increased risk of leaflet thickening. Post-dilatation of self-expanding THV as well as a supra-annular valve position seem to reduce the occurrence of this phenomenon....

Clinical observation of covered for malignant esophageal stricture and esophagus-bronchial fistula

International Nuclear Information System (INIS)

Luo Hailong; Lin Youen; Ye Zhi; Zhu Yifen

2010-01-01

Objective: To evaluate clinical value of self-expanded covered stents for advanced stage esophageal cancer complicated by esophageal stricture and esophagus-bronchial fistula. Methods: Self-expanded covered stents were placed into 48 patients with advanced stage esophageal cancer under fluoroscopy. Of the 48 patients, 39 had malignant esophageal stricture and 9 had esophagus-bronchus fistula. Results: Stents were successfully inserted into all but one patient with lower esophageal cancer and gastric volvulus. Deglutition was improved in all patients and coughing resolved in patients with esophagus-bronchus fistula. Thoracodynia and foreign body sensation vanished within one week after operation in all patients. Dyspnea caused by compression of the left main bronchus occurred in one patient. Re-stenosis of the stents occurred three to seven months after operation in eight patients. The mean survival time was seven months in all patients. Conclusion: Self-expanded covered stent placement is a simple, safe and reliable treatment method for advanced stage esophageal cancer and can effectively lengthen survival time. (authors)

Removal of Retrievable Self-Expandable Metallic Tracheobronchial Stents: An 18-Year Experience in a Single Center

International Nuclear Information System (INIS)

Park, Jung-Hoon; Kim, Pyeong Hwa; Shin, Ji Hoon; Tsauo, Jiaywei; Kim, Min Tae; Cho, Young Chul; Kim, Jin Hyoung; Song, Ho-Young

2016-01-01

PurposeThe purpose of the study was to retrospectively evaluate the technical outcomes of removal of retrievable self-expandable metallic stents (REMSs) and identify predictors of technical failure in 81 patients with benign and malignant tracheobronchial strictures.Materials and MethodsA total of 98 REMSs were removed under fluoroscopic guidance in 81 patients with benign (n = 48) or malignant (n = 33) tracheobronchial strictures. Primary and secondary technical success rates and complication rate were evaluated. Technical outcomes with regard to underlying diseases were also evaluated. Logistic regression models were constructed to identify predictors of primary technical success.ResultsPrimary and secondary technical success rates were 86.7 and 94.9 %, respectively. Stent removal-related complication rate was 7.1 % (7/98) and all were bleeding after stent removal. All bleeding complications were minor and managed conservatively. Primary technical success rate for benign strictures was significantly lower compared with that for malignant strictures (80.9 vs. 97.1 %, P = 0.029), but secondary technical success rate (93.7 vs. 97.1 %, P = 0.652) did not differ between the two groups. Granulation tissue formation was identified as an independent predictor of primary technical success (odds ratio 0.249, 95 % CI 0.071–0.874, P = 0.030).ConclusionRemoval of REMSs in patients with benign and malignant tracheobronchial strictures is safe and technically feasible. Bronchoscopic guidance may be required when the removal using a hook wire fails. The presence of granulation tissue was the negative predictor of primary technical success.

Application of Y-shaped, coated self-expandable metallic stents for anastomotic stenosis after gastrojejunostomy (Billroth II).

Science.gov (United States)

Li, Teng-Fei; Wu, Gang; Han, Xin-Wei; Shui, Shao-Feng; Ren, Jian-Zhuang; Li, Zhen; Ren, Ke-Wei

2017-01-01

Anastomotic stenosis is an infrequent but life-threatening complication after gastrojejunostomy (Billroth II). Tubular or single tubular stents have limited efficacy due to the particular anatomy. To assess the feasibility of a Y-shaped, fully-coated, self-expandable, metallic stent (SEMS) for anastomotic stenosis after gastrojejunostomy (Billroth II). Between January 2008 and August 2014, 14 patients (10 with gastric carcinoma and four with duodenal ulcers) had anastomotic stenoses following Billroth II reconstructions. Eight patients with gastric cancer had tumor recurrence near the anastomosis; two had benign strictures. The four duodenal ulcer patients had benign stenoses. An integrated Y-shaped, fully coated SEMS was designed to accord with the anatomy of residual gastrojejunal anastomotic strictures. Fourteen stents were inserted under fluoroscopic control. Follow-up was at 1, 3, 9, and 12 months, and then annually. All 14 stents were inserted successfully at the first attempt with a technical success rate of 100%. After stenting, abdominal symptoms resolved in all patients. All patients were followed up for 4-27 months (mean, 13.9 months). One of the eight recurrent cases died of multiple tumor metastases and liver failure after 7 months, without obstruction symptoms. In all six patients with benign anastomotic stenosis, the stents were removed successfully without complication and with no evidence of restenosis based on clinical evaluation and imaging. A Y-shaped, fully-coated SEMS proved to be a feasible and minimally invasive procedure for treating anastomotic stenosis after gastrojejunostomy (Billroth II). © The Foundation Acta Radiologica 2016.

Removal of Retrievable Self-Expandable Metallic Tracheobronchial Stents: An 18-Year Experience in a Single Center

Energy Technology Data Exchange (ETDEWEB)

Park, Jung-Hoon; Kim, Pyeong Hwa; Shin, Ji Hoon, E-mail: jhshin@amc.seoul.kr; Tsauo, Jiaywei; Kim, Min Tae; Cho, Young Chul; Kim, Jin Hyoung; Song, Ho-Young [University of Ulsan College of Medicine, Departments of Radiology and Research Institute of Radiology, Asan Medical Center (Korea, Republic of)

2016-11-15

PurposeThe purpose of the study was to retrospectively evaluate the technical outcomes of removal of retrievable self-expandable metallic stents (REMSs) and identify predictors of technical failure in 81 patients with benign and malignant tracheobronchial strictures.Materials and MethodsA total of 98 REMSs were removed under fluoroscopic guidance in 81 patients with benign (n = 48) or malignant (n = 33) tracheobronchial strictures. Primary and secondary technical success rates and complication rate were evaluated. Technical outcomes with regard to underlying diseases were also evaluated. Logistic regression models were constructed to identify predictors of primary technical success.ResultsPrimary and secondary technical success rates were 86.7 and 94.9 %, respectively. Stent removal-related complication rate was 7.1 % (7/98) and all were bleeding after stent removal. All bleeding complications were minor and managed conservatively. Primary technical success rate for benign strictures was significantly lower compared with that for malignant strictures (80.9 vs. 97.1 %, P = 0.029), but secondary technical success rate (93.7 vs. 97.1 %, P = 0.652) did not differ between the two groups. Granulation tissue formation was identified as an independent predictor of primary technical success (odds ratio 0.249, 95 % CI 0.071–0.874, P = 0.030).ConclusionRemoval of REMSs in patients with benign and malignant tracheobronchial strictures is safe and technically feasible. Bronchoscopic guidance may be required when the removal using a hook wire fails. The presence of granulation tissue was the negative predictor of primary technical success.

Removal of Retrievable Self-Expandable Metallic Tracheobronchial Stents: An 18-Year Experience in a Single Center.

Science.gov (United States)

Park, Jung-Hoon; Kim, Pyeong Hwa; Shin, Ji Hoon; Tsauo, Jiaywei; Kim, Min Tae; Cho, Young Chul; Kim, Jin Hyoung; Song, Ho-Young

2016-11-01

The purpose of the study was to retrospectively evaluate the technical outcomes of removal of retrievable self-expandable metallic stents (REMSs) and identify predictors of technical failure in 81 patients with benign and malignant tracheobronchial strictures. A total of 98 REMSs were removed under fluoroscopic guidance in 81 patients with benign (n = 48) or malignant (n = 33) tracheobronchial strictures. Primary and secondary technical success rates and complication rate were evaluated. Technical outcomes with regard to underlying diseases were also evaluated. Logistic regression models were constructed to identify predictors of primary technical success. Primary and secondary technical success rates were 86.7 and 94.9 %, respectively. Stent removal-related complication rate was 7.1 % (7/98) and all were bleeding after stent removal. All bleeding complications were minor and managed conservatively. Primary technical success rate for benign strictures was significantly lower compared with that for malignant strictures (80.9 vs. 97.1 %, P = 0.029), but secondary technical success rate (93.7 vs. 97.1 %, P = 0.652) did not differ between the two groups. Granulation tissue formation was identified as an independent predictor of primary technical success (odds ratio 0.249, 95 % CI 0.071-0.874, P = 0.030). Removal of REMSs in patients with benign and malignant tracheobronchial strictures is safe and technically feasible. Bronchoscopic guidance may be required when the removal using a hook wire fails. The presence of granulation tissue was the negative predictor of primary technical success.

Reintervention for stent occlusion after bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction.

Science.gov (United States)

Inoue, Tadahisa; Naitoh, Itaru; Okumura, Fumihiro; Ozeki, Takanori; Anbe, Kaiki; Iwasaki, Hiroyasu; Nishie, Hirotada; Mizushima, Takashi; Sano, Hitoshi; Nakazawa, Takahiro; Yoneda, Masashi; Joh, Takashi

2016-11-01

Endoscopic reintervention for stent occlusions following bilateral self-expandable metallic stent (SEMS) placement for malignant hilar biliary obstruction (MHBO) is challenging, and time to recurrent biliary obstruction (RBO) of the revisionary stent remains unclear. We aimed to clarify a suitable reintervention method for stent occlusions following bilateral SEMS placement for MHBO. Between 2002 and 2014, 52 consecutive patients with MHBO who underwent endoscopic reintervention for stent occlusion after bilateral SEMS placement were enrolled at two university hospitals and one tertiary care referral center. We retrospectively evaluated the technical and functional success rates of the reinterventions, and the time to RBO of the revisionary stents. Technical and functional success rates of the reinterventions were 92% (48/52) and 90% (43/48), respectively. Univariate analysis did not determine any significant predictive factors for technical and functional failures. Median time to RBO of the revisionary stents was 68 days. Median time to RBO was significantly longer for revisionary SEMS placement than for plastic stent placement (131 days vs 47 days, respectively; log-rank test, P = 0.005). Revisionary SEMS placement was the only independent factor that was significantly associated with a longer time to RBO of the revisionary stent in the multivariate Cox proportional hazards analysis (hazard ratio 0.37; 95% confidence interval 0.14-0.95; P = 0.039). Revisionary SEMS placement is a suitable endoscopic reintervention method for stent occlusion following bilateral SEMS placement from the perspective of time to RBO of the revisionary stent. © 2016 Japan Gastroenterological Endoscopy Society.

Use of the covered Y-shaped metallic stent in the treatment of airway stenoses involving the lower trachea and the tracheal carina: preliminary clinical study

International Nuclear Information System (INIS)

Yang Ruimin; Li Fenbao; Zhang Mingqiu; Wu Gang; Han Xinwei

2007-01-01

Objective: To describe a new kind of Y-shaped metallic stent delivery system and evaluate its feasibility and preliminary effect for managing multiple airway stenoses involving the lower trachea and the tracheal carina. Methods: The Y-shaped metallic stent delivery system consisted of three-tier structure. The inner-tier was composed of four parallel guiding tubes, which was used for two guidewires and two threads passing through, the middle-tier was delivery catheter, which contained the four guiding tubes, and the outer-tier was introducer sheath. Under the fluoroscopic guidance, 15 patients with multiple stenoses involving the lower trachea and the tracheal carina were treated with the new covered self-expandable Y-shaped metallic stents. Results: Stent placement in the tracheo-bronchial tree was technically successful in all patients with obliteration of the dyspnea immediately after stent placement, and SaO2 was increased form preoperative 75%-89% to postoperative 96%-99%. During follow-up a period of 3-58 weeks (M 22 weeks), all stenosis were resolved without stent-related complications, and the general physical of all 15 patents was improved with no occurrence of obviously dyspnea and bleeding. Karnofsky performance status (KPS) was improved from preoperative 26%-45% to postoperative 72%-95%. Five patients died of the following causes unrelated to stent insertion: multiple organ failure (n=3), cachexia (n=1) and pulmonary infection caused by gastrobronehial fistula (n=1), and the remaining 10 patients were alive with no evidence of dyspnea at the time of this report. Conclusion: Deployment of the covered Y-shaped metallic stent with the use of Y metallic stent delivery system in the management of airway stenoses involving the lower trachea and the tracheal carina was a simple and safe procedure and with a good short-term clinical efficacy. (authors)

Use of the covered Y-shaped metallic stent in the treatment of airway stenoses involving the lower trachea and the tracheal carina: preliminary clinical study

Energy Technology Data Exchange (ETDEWEB)

Ruimin, Yang; Fenbao, Li; Mingqiu, Zhang [Department of Intervention, First Affiliated Hospital, Xinxiang Medical Univ., Xinxiang (China); Gang, Wu; Xinwei, Han

2007-09-15

Objective: To describe a new kind of Y-shaped metallic stent delivery system and evaluate its feasibility and preliminary effect for managing multiple airway stenoses involving the lower trachea and the tracheal carina. Methods: The Y-shaped metallic stent delivery system consisted of three-tier structure. The inner-tier was composed of four parallel guiding tubes, which was used for two guidewires and two threads passing through, the middle-tier was delivery catheter, which contained the four guiding tubes, and the outer-tier was introducer sheath. Under the fluoroscopic guidance, 15 patients with multiple stenoses involving the lower trachea and the tracheal carina were treated with the new covered self-expandable Y-shaped metallic stents. Results: Stent placement in the tracheo-bronchial tree was technically successful in all patients with obliteration of the dyspnea immediately after stent placement, and SaO2 was increased form preoperative 75%-89% to postoperative 96%-99%. During follow-up a period of 3-58 weeks (M 22 weeks), all stenosis were resolved without stent-related complications, and the general physical of all 15 patents was improved with no occurrence of obviously dyspnea and bleeding. Karnofsky performance status (KPS) was improved from preoperative 26%-45% to postoperative 72%-95%. Five patients died of the following causes unrelated to stent insertion: multiple organ failure (n=3), cachexia (n=1) and pulmonary infection caused by gastrobronehial fistula (n=1), and the remaining 10 patients were alive with no evidence of dyspnea at the time of this report. Conclusion: Deployment of the covered Y-shaped metallic stent with the use of Y metallic stent delivery system in the management of airway stenoses involving the lower trachea and the tracheal carina was a simple and safe procedure and with a good short-term clinical efficacy. (authors)

Pancreatitis-Associated Splenic Artery Pseudoaneurysm: Endovascular Treatment with Self-Expandable Stent-Grafts

International Nuclear Information System (INIS)

Brountzos, Elias N.; Vagenas, Kostantinos; Apostolopoulou, Sotiria C.; Panagiotou, Irene; Lymberopoulou, Dimitra; Kelekis, Dimitrios A.

2003-01-01

We present a patient with a splenic arterypseudoaneurysm (SAPA) treated with placement of self-expandable stent-grafts. The procedure was complicated by stent-graft migration,but successful management resulted in lasting exclusion of the SAPA,while the patency of the splenic artery was preserved. This is the first report of self-expandable stent-graft treatment of SAPA

Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

International Nuclear Information System (INIS)

Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

2015-01-01

Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

Self-expanding metallic stent as a bridge to surgery in the treatment of left colon cancer obstruction: Cost-benefit analysis and oncologic results.

Science.gov (United States)

Flor-Lorente, Blas; Báguena, Gloria; Frasson, Matteo; García-Granero, Alvaro; Cervantes, Andrés; Sanchiz, Vicente; Peña, Andres; Espí, Alejandro; Esclapez, Pedro; García-Granero, Eduardo

2017-03-01

The use of a self-expanding metallic stent as a bridge to surgery in acute malignant left colonic obstruction has been suggested as an alternative treatment to emergency surgery. The aim of the present study was to compare the morbi-mortality, cost-benefit and long-term oncological outcomes of both therapeutic options. This is a prospective, comparative, controlled, non-randomized study (2005-2010) performed in a specialized unit. The study included 82 patients with left colon cancer obstruction treated by stent as a bridge to surgery (n=27) or emergency surgery (n=55) operated with local curative intention. The main outcome measures (postoperative morbi-mortaliy, cost-benefit, stoma rate and long-term oncological outcomes) were compared based on an "intention-to-treat" analysis. There were no significant statistical differences between the two groups in terms of preoperative data and tumor characteristics. The technically successful stenting rate was 88.9% (11.1% perforation during stent placement) and clinical success was 81.4%. No difference was observed in postoperative morbi-mortality rates. The primary anastomosis rate was higher in the bridge to surgery group compared to the emergency surgery group (77.8% vs. 56.4%; P=.05). The mean costs in the emergency surgery group resulted to be €1,391.9 more expensive per patient than in the bridge to surgery group. There was no significant statistical difference in oncological long-term outcomes. The use of self-expanding metalllic stents as a bridge to surgery is a safe option in the urgent treatment of obstructive left colon cancer, with similar short and long-term results compared to direct surgery, inferior mean costs and a higher rate of primary anastomosis. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

[Self-expanding nitinol stents in proximal tracheal stenosis].

Science.gov (United States)

Hafner, B; Mann, W; Heussel, C P; Scherhag, A; Schlegel, J; Kauczor, H U

2000-03-01

The use of silicone- or metal stents in stenosis of the distal trachea and the bronchial system is a customary procedure [1-4], for example after tumor invasion or cicatricial stenosis after transplantation. In the proximal part of the trachea, on smaller, short and soft strictures we try to stabilise the trachea by the implantation of rings. Other methods are tracheal plasty or transverse tracheal resectomy [5-7]. In the case of longer or nearer subglottal stenoses the positioning of self-expanding nitinol stents has proven a simple, gentle and well-tolerated alternative procedure even in very serious disorders [1, 8, 9]. These stents can be placed in short narcosis under endoscopic control without great strain on the patient. We placed nitinol-stents in the proximal part of the trachea in eleven cases. In five cases dyspnoea caused by a tracheal collapse improved. In two further cases a tracheal stenosis with massive granulation tissue and cicatricial pull under an inlaid tracheal cannula was removed and the tracheostoma was closed. In four cases a solid, scarred and cartilaginous stenosis in the area of the cricoid and the upper tracheal rings was widened with laser and later on stented. Over an observation time of two years no complications showed safe one case in which a directly postoperative dislocation was repositioned quickly. The patients live without restrictions through the tracheal stenosis or a tracheostoma. In the best possible case epithelialization over the metal meshes develops so that a nearly normal mucus transportation is possible [1, 10-12].

Plastic vs. Self-Expandable Metal Stents for Palliation in Malignant Biliary Obstruction: A Series of Meta-Analyses.

Science.gov (United States)

Almadi, Majid A; Barkun, Alan; Martel, Myriam

2017-02-01

Self-expandable metal stents (SEMS) are thought to have an advantage over plastic stents in achieving biliary drainage. We performed a systematic search of MEDLINE, EMBASE, Scopus, CENTRAL, and ISI Web of knowledge databases, from January 1980 to September 2015, for randomized-controlled trials (RCTs) comparing SEMS vs. plastic stents in the palliation of malignant biliary obstruction. Primary outcomes were durations of stent patency, patient survival, and 30-day mortality. Numerous secondary outcomes were assessed, and extensive sensitivity and subgroup analyses were performed. In all, 20 RCTs totaling 1,713 patients yielded a weighted mean difference (WMD) in time to stent patency (4 studies) of 4.45 months (95% confidence interval (CI), 0.31, 8.59; GRADE=moderate) favoring SEMS. There were no differences in overall patient survival (5 studies) WMD=0.67 months (95% CI, -0.66, 1.99; GRADE=moderate), or 30-day mortality (8 studies) odds ratio (OR)=0.80 (95% CI, 0.52, 1.24; GRADE=moderate) but there was a higher symptom-free survival at 6 months (4 studies) OR=5.96 (95% CI, 1.71, 20.81; GRADE=moderate). SEMS use resulted in lower rates of late complications (11 studies) OR=0.43 (95% CI, 0.26, 0.71; GRADE=moderate), sepsis or cholangitis (14 studies) OR=0.53 (95% CI, 0.37, 0.77; GRADE=high), blocking from sludge (8 studies) OR=0.11(95% CI, 0.07, 0.17; GRADE=moderate), and mean number of re-interventions (8 studies) WMD=-0.83 interventions (95% CI, -1.64, -0.02; GRADE=moderate). There was a longer patency of SEMS for those without a prior drainage attempt (2 studies) WMD 7.70 months (95% CI, 7.14, 8.25; GRADE=high). Although a survival advantage was found when an uncovered SEMS was used (3 studies) WMD 1.31 months (95% CI, 0.30, 2.32; GRADE=high), but not partially or fully covered SEMS (2 studies) WMD -0.66 months (95% CI, -1.02, -0.30; GRADE=high) vs. plastic stents, and for SEMS in the setting of pre- or post-procedural antibiotic administration (2 studies) WMD 1

Safety of endoscopic removal of self-expandable stents after treatment of benign esophageal diseases

NARCIS (Netherlands)

van Halsema, Emo E.; Wong Kee Song, Louis M.; Baron, Todd H.; Siersema, Peter D.; Vleggaar, Frank P.; Ginsberg, Gregory G.; Shah, Pari M.; Fleischer, David E.; Ratuapli, Shiva K.; Fockens, Paul; Dijkgraaf, Marcel G. W.; Rando, Giacomo; Repici, Alessandro; van Hooft, Jeanin E.

2013-01-01

Temporary placement of self-expandable stents has been increasingly used for the management of benign esophageal diseases. To evaluate the safety of endoscopic removal of esophageal self-expandable stents placed for the treatment of benign esophageal diseases. Multicenter retrospective study. Six

Insertion of a self-expandable endotracheal metal stent using topical anaesthesia and a fibreoptic bronchoscope: a comfortable way to offer palliation.

OpenAIRE

Coolen, D.; Slabbynck, H.; Galdermans, D.; Van Schaardenburg, C.; Mortelmans, L. L.

1994-01-01

A self-expandable stent was used to obtain prolonged relief of stridor resulting from tracheal obstruction by extrinsic tumour compression despite prior external irradiation. The stent was inserted in an easy and comfortable procedure with fibreoptic bronchoscopy under local anaesthesia.

A comparison of the temporary placement of 3 different self-expanding stents for the treatment of refractory benign esophageal strictures: a prospective multicentre study

Directory of Open Access Journals (Sweden)

Canena Jorge Manuel

2012-06-01

Full Text Available Abstract Background Refractory benign esophageal strictures (RBESs have been treated with the temporary placement of different self-expanding stents with conflicting results. We compared the clinical effectiveness of 3 types of stents: self-expanding plastic stents (SEPSs, biodegradable stents, and fully covered self-expanding metal stents (FCSEMSs, for the treatment of RBES. Methods This study prospectively evaluated 3 groups of 30 consecutive patients with RBESs who underwent temporary placement of either SEPSs (12 weeks, n = 10, biodegradable stents (n = 10 or FCSEMSs (12 weeks, n = 10. Data were collected to analyze the technical success and clinical outcome of the stents as evaluated by recurrent dysphagia, complications and reinterventions. Results Stent implantation was technically successful in all patients. Migration occurred in 11 patients: 6 (60% in the SEPS group, 2 (20% in the biodegradable group and 3 (30% in the FCSEMS group (P = 0.16. A total of 8/30 patients (26.6% were dysphagia-free after the end of follow-up: 1 (10% in the SEPS group, 3 (30% in the biodegradable group and 4 (40% in the FCSEMS group (P = 0.27. More reinterventions were required in the SEPS group (n = 24 than in the biodegradable group (n = 13 or the FCSEMS group (n = 13 (P = 0.24. Multivariate analysis showed that stricture length was significantly associated with higher recurrence rates after temporary stent placement (HR = 1.37; 95% CI = 1.08-1.75; P = 0.011. Conclusions Temporary placement of a biodegradable stent or of a FCSEMS in patients with RBES may lead to long-term relief of dysphagia in 30 and 40% of patients, respectively. The use of SEPSs seems least preferable, as they are associated with frequent stent migration, more reinterventions and few cases of long-term improvement. Additionally, longer strictures were associated with a higher risk of recurrence.

[Treatment of tracheobronchomalacia with expandable metallic stents].

Science.gov (United States)

Antón-Pacheco Sánchez, J; García Vázquez, A; Cuadros García, J; Cano Novillo, I; Villafruela Sanz, M; Berchi García, F J

2002-10-01

Tracheomalacia is an unfrequent disease that causes tracheal collapse during breathing. It is generally associated to esophageal atresia, but cases of primary tracheomalacia and others secondary to extrinsic compression, have also been described. Spontaneous resolution is generally the rule and only a few cases need surgical treatment. When this therapy fails or is not indicated for any reason, endoluminal tracheobronchial stents may be used. We have treated two patients with four expandable metallic stents: one had severe tracheomalacia associated to esophageal atresia and the other tracheobronchomalacia secondary to cardiomegaly. Results have been good in both cases.

The New Nitinol Conformable Self-Expandable Metal Stents for Malignant Colonic Obstruction: A Pilot Experience as Bridge to Surgery Treatment

Directory of Open Access Journals (Sweden)

Roberto Di Mitri

2014-01-01

Full Text Available Introduction. Self-expandable metal stents (SEMS are a nonsurgical option for treatment of malignant colorectal obstruction also as a bridge to surgery approach. The new nitinol conformable stent has improved clinical outcomes in these kinds of patients. We report a pilot experience with nitinol conformable SEMS placement as bridge to surgery treatment in patients with colorectal obstruction. Materials and Methods. Between April and August 2012, we collected data on colonic nitinol conformable SEMS placement in a cohort of consecutive symptomatic patients, with malignant colorectal obstruction, who were treated as a bridge to surgery. Technical success, clinical success, and adverse events were recorded. Results. Ten patients (7 male (70%, with a mean age of 69.2 ± 10.1, were evaluated. The mean length of the stenosis was 3.6 ± 0.6 cm. Five patients (50% were treated on an emergency basis. The median time from stent placement to surgery was 16 days (interquartile range 7–21. Technical and clinical success was achieved in all patients with a significant early improvement of symptoms. No adverse events due to the SEMS placement were observed. Conclusion. This pilot study confirmed the important role of nitinol conformable SEMS as a bridge to surgery option in the treatment of symptomatic malignant colorectal obstruction.

Differences in Endothelial Injury After Balloon Angioplasty, Insertion of Balloon-Expanded Stents or Release of Self-Expanding Stents: An Electron Microscopic Experimental Study

International Nuclear Information System (INIS)

Harnek, Jan; Zoucas, Evita; Carlemalm, Erik; Cwikiel, Wojciech

1999-01-01

Purpose: To evaluate which of six different commonly available stents inserted into an artery without percutaneous transluminal angioplasty (PTA) causes the least endothelial damage. To compare the degree of endothelial injury after insertion of such a stent with injury caused by PTA. Methods: Twelve healthy pigs were used in the experiments. In the first part of the study six different types of stents were inserted into the common iliac arteries. In the second part of the study self-expanding stents with large spaces between the wires were used. PTA was performed in the contralateral iliac artery. The pigs were killed immediately after the procedure and resected specimens examined after fixation, using scanning electron microscopy. Results: All procedures but two were accomplished successfully. More endothelium was preserved after insertion of self-expanding stents with large spaces between the wires, compared with stents with small spaces and balloon-expanded stents. After insertion of self-expanding stents with large spaces, 50.1% ± 16.4% of the endothelium remained intact, compared with only 5.6% ± 7.7% after PTA. The difference was statistically significant (p < 0.001). Conclusion: Self-expanding stents with large spaces between the wires, inserted without PTA, cause less damage to the endothelium than other stents and significantly less damage than PTA

Expandable metallic stents in the palliative treatment of malignant tracheobronchial stenosis

Energy Technology Data Exchange (ETDEWEB)

Park, Jong Woong; Jung, Gyoo Sik; Kim, Seong Min; Lee, Seung Ryong; Kim, Hyun Sook; Huh, Jin Do; Joh, Young Duk [Kosin Medical College, Pusan (Korea, Republic of)

1998-05-01

The purpose of this study is to report the outcome of using expandable metallic stent in the management of malignant tracheobronchial stenosis with dyspnea. Under fluoroscopic and bronchoscopic guidance, seven patients with malignant airway stenosis were treated with ten expandable metallic stents. The cause of stenosis was metastasis from esophageal cancer in five patients, recurrent adenoid cystic carcinoma of the trachea in one, and primary lung cancer in one. The major sites of obstruction were the trachea in four patients, the left main bronchus in one, the trachea and left main bronchus in one, and the trachea and both bronchi in one. Chest radiography (n=7), bronchoscopy (n=5), pulmonary function test (PFT)(n=3), and spirometry(n=1) were performed before and after stent placement. In all seven patients, the stent was successfully placed at the lesion sites and dyspnea began to improve immediately. After the procedure, chest radiography and bronchoscopy showed an increase in airway diameter. After the procedure, chest radiography and bronchoscopy showed an increase in airway diameter. After stent placement, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) improved 53% and 56%, respectively. Peak flow velocity also changed from 46 L/min to 200 L/min. During median follow-up of 67 (41-1565) days, one stent migration occurred. In one patient, proximal tumor overgrowth occurred, and in one, tumor ingrowth was treated with balloon dilatation. For in the palliative treatment of malignant tracheobronchial stenosis with dyspnea, placement of expandable metal stents is safe and effective. (author). 21 refs., 1 tabs., 3 figs.

Expandable metallic stents in the palliative treatment of malignant tracheobronchial stenosis

International Nuclear Information System (INIS)

Park, Jong Woong; Jung, Gyoo Sik; Kim, Seong Min; Lee, Seung Ryong; Kim, Hyun Sook; Huh, Jin Do; Joh, Young Duk

1998-01-01

The purpose of this study is to report the outcome of using expandable metallic stent in the management of malignant tracheobronchial stenosis with dyspnea. Under fluoroscopic and bronchoscopic guidance, seven patients with malignant airway stenosis were treated with ten expandable metallic stents. The cause of stenosis was metastasis from esophageal cancer in five patients, recurrent adenoid cystic carcinoma of the trachea in one, and primary lung cancer in one. The major sites of obstruction were the trachea in four patients, the left main bronchus in one, the trachea and left main bronchus in one, and the trachea and both bronchi in one. Chest radiography (n=7), bronchoscopy (n=5), pulmonary function test (PFT)(n=3), and spirometry(n=1) were performed before and after stent placement. In all seven patients, the stent was successfully placed at the lesion sites and dyspnea began to improve immediately. After the procedure, chest radiography and bronchoscopy showed an increase in airway diameter. After the procedure, chest radiography and bronchoscopy showed an increase in airway diameter. After stent placement, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) improved 53% and 56%, respectively. Peak flow velocity also changed from 46 L/min to 200 L/min. During median follow-up of 67 (41-1565) days, one stent migration occurred. In one patient, proximal tumor overgrowth occurred, and in one, tumor ingrowth was treated with balloon dilatation. For in the palliative treatment of malignant tracheobronchial stenosis with dyspnea, placement of expandable metal stents is safe and effective. (author). 21 refs., 1 tabs., 3 figs

Endovascular therapy of carotid stenosis with self-expandable stent

International Nuclear Information System (INIS)

Liu Jianmin; Huang Qinghai; Hong Bo; Xu Yi; Zhao Wenyuan; Zhang Yongwei; Zhang Long; Zhou Xiaoping

2002-01-01

Objective: To summarize the experience of endovascular treatment of carotid stenosis with expandable stents. Methods: Fifty-two patients with carotid stenosis who experienced repeated transient ischemic attacks or cerebral infarction were admitted to our hospital. The stenosis was pre-expanded with undetachable balloon, and self-expandable stents were implanted across the stenosis. A balloon catheter was used to further expand stents in 29 patients. Results: The stent was accurately implanted, and total disappearance of stenosis was obtained in 34 patients, the degree of stenosis reduced more than 90% in 16 patients, and more than 70% in 2 patients. The patients recovered well and no complications related to the procedure occurred. None experienced TIA or infarction postoperatively in 52 cases and follow-up imaging in 19 patients (6 - 12 months) demonstrated no restenosis. Conclusion: Endovascular stenting may be a safe and valid choice for the treatment of extracranial carotid stenosis

Endotracheal expandable metallic stent placement in dogs

Energy Technology Data Exchange (ETDEWEB)

Sawada, S; Tanabe, Y; Fujiwara, Y; Koyama, T; Tanigawa, N; Kobayashi, M; Katsube, Y; Nakamura, H [Tottori Univ. School of Medicine, Yonago (Japan). Dept. of Radiology Research Inst. for Microbial Diseases, Osaka (Japan). Dept. of Radiology

1991-01-01

Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. These stents were constructed of 0.45, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface. (orig.).

Ultrathin endoscope-assisted self-expandable metallic stent placement following initial unsuccessful attempt in malignant upper gastrointestinal obstruction.

Science.gov (United States)

Park, Se Woo; Lee, Hyuk; Park, Jun Chul; Shin, Sung Kwan; Lee, Sang Kil; Lee, Yong Chan

2014-03-01

Conventional endoscopy for self-expandable metallic stent (SEMS) placement may be technically limited in long and tortuous strictures. Therefore, we analyzed the feasibility, safety and usefulness of ultrathin endoscopy (UTE)-guided SEMS placement. This study involved 24 patients with upper gastrointestinal obstruction and unsuccessful initial attempts to place SEMS using conventional endoscopy. After completely passing a UTE across the stricture, the UTE was withdrawn, leaving a guidewire placed via the working channel. Through-the-scope SEMS placement was done using a conventional endoscope inserted along the guidewire. The primary endpoints were assessed by technical/clinical success and stent patency duration. Stents were successfully placed at target locations in all but one case with a long tortuous stricture, with 95.8% (23/24) technical success. One week after stent placement, mean gastricoutlet obstruction score improved significantly from baseline (1.74 ± 0.62 and 0.33 ± 0.48, respectively; P Stent migration, restenosis, and fracture occurred in four (17.4%), six (26.1%), and one (4.3%) of 23 stents, respectively. Median stent patency duration was 79 days. Mean stent patency was significantly longer in patients who received palliative chemotherapy than in those who did not (122.9 ± 11.0 and 38.3 ± 4.6, respectively; P < 0.001). UTE guidance SEMS delivery can be a feasible and safe rescue treatment method for malignant upper gastrointestinal obstruction in cases of failed attempts to place SEMS using conventional endoscopy. Our result warrants a further study to define the efficacy of this method in difficult SEMS placement cases. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

A theoretical model of grain boundary self-diffusion in metals with phase transitions (case study into titanium and zirconium)

Science.gov (United States)

Semenycheva, Alexandra V.; Chuvil'deev, Vladimir N.; Nokhrin, Aleksey V.

2018-05-01

The paper offers a model describing the process of grain boundary self-diffusion in metals with phase transitions in the solid state. The model is based on ideas and approaches found in the theory of non-equilibrium grain boundaries. The range of application of basic relations contained in this theory is shown to expand, as they can be used to calculate the parameters of grain boundary self-diffusion in high-temperature and low-temperature phases of metals with a phase transition. The model constructed is used to calculate grain boundary self-diffusion activation energy in titanium and zirconium and an explanation is provided as to their abnormally low values in the low-temperature phase. The values of grain boundary self-diffusion activation energy are in good agreement with the experiment.

The use of balloon-expandable metallic stents in the treatment of pediatric tracheomalacia and bronchomalacia.

Science.gov (United States)

Furman, R H; Backer, C L; Dunham, M E; Donaldson, J; Mavroudis, C; Holinger, L D

1999-02-01

To evaluate the use of balloon-expandable metallic stents in the treatment of children with tracheomalacia and bronchomalacia in whom conventional therapy has failed. Retrospective case series. Tertiary pediatric otolaryngology and cardiothoracic surgery referral center. Six patients were identified as having undergone bronchoscopic placement of metallic balloon-expandable stents between 1994 and 1997. The age at stent placement, prior surgical interventions, and indications for and sites of stent placement were noted. Also, the complications related to stent placement and the current airway status of the patients were reviewed. Twelve balloon-expandable metallic angioplasty stents (Palmaz; Johnson & Johnson Interventional Systems Co, Warren, NJ) were placed bronchoscopically in 6 patients. Six stents were placed in the lower trachea, and 6 were placed in the main bronchi. The stents were balloon expanded under fluoroscopic guidance. Discontinuation of mechanical ventilation. The age at stent placement ranged from 1.5 to 38 months (mean age at placement, 10 months). The indications for stent placement were (1) tracheomalacia or bronchomalacia, (2) pericardial patch or slide tracheoplasty failure, and (3) bronchomalacia caused by tetralogy of Fallot and large pulmonary arteries. The primary complication of stent placement was postoperative granulation tissue formation. One patient required the removal of 2 tracheal stents because of granulation tissue formation. There were 2 deaths in the series, 1 possibly related to stent placement. Four of the 6 patients were weaned from mechanical ventilation, and 3 experienced prolonged relief of airway obstruction. Metallic balloon-expandable stents are effective in relieving lower tracheomalacia and bronchomalacia in select patients. Only patients in whom conventional therapy has failed should be considered for stent placement.

Esophageal leiomyoma in a dog causing esophageal distension and treated by transcardial placement of a self-expanding, covered, nitinol esophageal stent.

Science.gov (United States)

Robin, Elisabeth M; Pey, Pascaline B; de Fornel-Thibaud, Pauline; Moissonnier, Pierre H M; Freiche, Valérie

2018-02-01

CASE DESCRIPTION A 10-year-old spayed female Rottweiler was referred for evaluation because of a 2-month history of regurgitation and weight loss, despite no apparent change in appetite. The dog had received antiemetic and antacid treatment, without improvement. CLINICAL FINDINGS Physical examination revealed a low body condition score (2/5), but other findings were unremarkable. Diffuse, global esophageal dilatation was noted on plain thoracic radiographs, and normal motility was confirmed through videofluoroscopic evaluation of swallowing. Transhepatic ultrasonographic and CT examination revealed a circumferential, intraparietal lesion in the distal portion of the esophagus causing distal esophageal or cardial subobstruction and no metastases. Incisional biopsy of the lesion was performed, and findings of histologic examination supported a diagnosis of esophageal leiomyoma. TREATMENT AND OUTCOME In view of numerous possible complications associated with esophageal surgery, the decision was made to palliatively treat the dog by transcardial placement of a self-expanding, covered, nitinol esophageal stent under endoscopic guidance. Two weeks after stent placement, radiography revealed complete migration of the stent into the gastric lumen. Gastrotomy was performed, and the stent was replaced and fixed in place. Twenty-four months after initial stent placement, the dog had a healthy body condition and remained free of previous clinical signs. CLINICAL RELEVANCE Diffuse benign muscular neoplasia should be considered as a differential diagnosis for acquired esophageal dilatation in adult and elderly dogs. In the dog of this report, transcardial stent placement resulted in resolution of the clinical signs, with no apparent adverse effect on digestive function. The described procedure could be beneficial for nonsurgical treatment of benign esophageal tumors in dogs.

Management of acute malignant colorectal obstruction with a novel self-expanding metallic stent as a bridge to surgery

International Nuclear Information System (INIS)

Li Yongdong; Cheng Yingsheng; Li Minghua; Fan Youben; Chen Niwei; Wang Yu; Zhao Jungong

2010-01-01

Purpose: To prospectively evaluate the safety and clinical efficacy of a newly designed self-expandable metallic stent (SEMS) in the treatment of patients with acute malignant colorectal obstruction. Methods: Between April 2001 and October 2007, 52 patients with acute malignant colorectal obstruction were treated with a new designed SEMS as an investigational bridge to surgery. Patients were prospectively followed and relevant data collection was collected, including details regarding technique, clinical symptoms, complications, need for elective surgery, and overall survival. Results: Stent placement was technically successful in all but two patients (due to complete obstruction) with no procedure-related complications. Complications included stent migration (n = 4), anal pain (n = 2) and stool impaction (n = 1). Clinical success was achieved in 49 (98%) of 50 patients with resolution of bowel obstruction within 2 days of stent placement. In one patient with stool impaction 2 days after stent placement, endoscopic disimpaction was successfully performed. An elective one-stage surgical procedure was performed in all 50 patients who successfully received a SEMS as a bridge to surgery within a mean of 8 ± 2 days (range: 4-11 days) after stent placement. Mean follow-up time was 36 ± 12 months (range 3-70 months), and all patients remained alive at the time of this report. Conclusion: The newly designed SEMS placement as a bridge to surgery was a safe and effective intervention for colonic decompression in patients with acute malignant colorectal obstruction and allowed a high proportion of patients to be successfully proceeded to elective surgery.

Endoscopic management of complications of self-expandable metal stents for treatment of malignant esophageal stenosis and tracheoesophageal fistulas.

Science.gov (United States)

Bor, Renáta; Fábián, Anna; Bálint, Anita; Farkas, Klaudia; Szűcs, Mónika; Milassin, Ágnes; Czakó, László; Rutka, Mariann; Molnár, Tamás; Szepes, Zoltán

2017-08-01

Self-expandable metal stent (SEMS) implantation may rapidly improve the symptoms of malignant esophageal stenosis and tracheoesophageal fistulas (TEF). However, dysphagia often returns subsequently and repeated endoscopic intervention may be necessary. The aims of the study were to identify the risk factors of complications, and the frequency and efficacy of repeated endoscopic interventions; and to provide technical recommendations on appropriate stent selection. We analyzed retrospectively the clinical data of 212 patients with locally advanced esophageal cancer who underwent SEMS implantation. A total of 238 SEMS implantations were performed with 99.06% technical success and 1.26% procedure-related deaths in the enrolled 212 cases. Complications occurred in 84 patients (39.62%) and in 55 cases (25.94%) repeated endoscopic procedures were required. Early reintervention 24-48 h after the stent implantations was necessary due to stent migration (12 cases), arrhythmia (2 cases), intolerable retrosternal pain (1 case) and dyspnea (1 case). An average of 1.98 repeated gastroscopies (range 1-6; median 2), 13.58 weeks (range 1.5-48; median 11) after the stent implantation were performed during the follow-up period: 37 stent repositions, 23 restent implantations, 15 endoscopic esophageal dilations and 7 stent removals. In 48 cases (87.3%) oral feeding of patients was made possible by endoscopic interventions. In a quarter of SEMS implantations, complications occur that can be successfully managed by endoscopic interventions. Our experiences have shown that individualized stent choice may substantially reduce the complications rate and make repeated endoscopic interventions easier.

Self-expandable metallic stent as a bridge to elective surgery versus emergency surgery for acute malignant colorectal obstruction.

Science.gov (United States)

Li, Zhi-Xiong; Wu, Xiao-Hua; Wu, Hai-yan; Chang, Wen-Ju; Chang, Xiu-juan; Yi, Tuo; Shi, Qiang; Chen, Jing-Wen; Feng, Qing-Yang; Zhu, De-Xiang; Wei, Ye; Zhong, Yun-Shi; Xu, Jian-Min

2016-03-01

The efficacy and safety of self-expandable metallic stents (SEMSs) as a bridge for patients with acute malignant colorectal obstructions (AMCOs) are still controversial. We conducted this study to evaluate the outcomes of patients with AMCOs treated by different strategies. From January 2010 to March 2014, a total of 171 patients with AMCOs from Zhongshan Hospital were retrospectively enrolled in this study. One hundred twenty patients successfully received stent placement followed by one-stage laparoscopic or open resection in the stent group, and 51 patients received emergency operations in the emergency group. The operation duration and postoperative hospital stay were significantly shorter in the stent group (114.51 ± 28.65 vs. 160.39 ± 58.94 min, P stent group also had significantly reduced intraoperative blood loss and the incidence of postoperative complications compared with the emergency group (61.00 ± 43.70 vs. 121.18 ± 85.90 ml, P stent group was significantly longer than that in the emergency group (53 vs. 41 months, P = 0.034). In subgroup analysis of stent group, the stent laparoscopy group had significantly decreased postoperative complications (P = 0.025), and similar long-term survival (P = 0.81). Stent placement as a bridge to surgery is a safe and feasible procedure and provides significant advantages in terms of short-term outcomes and favorable prognoses for patients with AMCOs. Laparoscopic surgery could be considered as an optimal treatment after stent placement.

Management of acute malignant colorectal obstruction with a novel self-expanding metallic stent as a bridge to surgery

Energy Technology Data Exchange (ETDEWEB)

Li Yongdong [Department of Radiology and Research Institute of Radiology, Sixth Affiliated People' s Hospital, Shanghai Jiao Tong University, No. 600, Yi Shan Road, Shanghai 200233 (China); Cheng Yingsheng [Department of Radiology and Research Institute of Radiology, Sixth Affiliated People' s Hospital, Shanghai Jiao Tong University, No. 600, Yi Shan Road, Shanghai 200233 (China); Department of Radiology, Tenth Affiliated People' s Hospital, Shanghai Tong Ji University, No. 301, Middle Yan Chang Road, Shanghai 200072 (China)], E-mail: chengys@sh163.net; Li Minghua [Department of Radiology and Research Institute of Radiology, Sixth Affiliated People' s Hospital, Shanghai Jiao Tong University, No. 600, Yi Shan Road, Shanghai 200233 (China); Fan Youben; Chen Niwei; Wang Yu [Department of Gastroenterology, Sixth Affiliated People' s Hospital, Shanghai Jiao Tong University (China); Zhao Jungong [Department of Radiology and Research Institute of Radiology, Sixth Affiliated People' s Hospital, Shanghai Jiao Tong University, No. 600, Yi Shan Road, Shanghai 200233 (China)

2010-03-15

Purpose: To prospectively evaluate the safety and clinical efficacy of a newly designed self-expandable metallic stent (SEMS) in the treatment of patients with acute malignant colorectal obstruction. Methods: Between April 2001 and October 2007, 52 patients with acute malignant colorectal obstruction were treated with a new designed SEMS as an investigational bridge to surgery. Patients were prospectively followed and relevant data collection was collected, including details regarding technique, clinical symptoms, complications, need for elective surgery, and overall survival. Results: Stent placement was technically successful in all but two patients (due to complete obstruction) with no procedure-related complications. Complications included stent migration (n = 4), anal pain (n = 2) and stool impaction (n = 1). Clinical success was achieved in 49 (98%) of 50 patients with resolution of bowel obstruction within 2 days of stent placement. In one patient with stool impaction 2 days after stent placement, endoscopic disimpaction was successfully performed. An elective one-stage surgical procedure was performed in all 50 patients who successfully received a SEMS as a bridge to surgery within a mean of 8 {+-} 2 days (range: 4-11 days) after stent placement. Mean follow-up time was 36 {+-} 12 months (range 3-70 months), and all patients remained alive at the time of this report. Conclusion: The newly designed SEMS placement as a bridge to surgery was a safe and effective intervention for colonic decompression in patients with acute malignant colorectal obstruction and allowed a high proportion of patients to be successfully proceeded to elective surgery.

Fluoroscopic removal of retrievable self-expandable metal stents in patients with malignant oesophageal strictures: Experience with a non-endoscopic removal system.

Science.gov (United States)

Kim, Pyeong Hwa; Song, Ho-Young; Park, Jung-Hoon; Zhou, Wei-Zhong; Na, Han Kyu; Cho, Young Chul; Jun, Eun Jung; Kim, Jun Ki; Kim, Guk Bae

2017-03-01

To evaluate clinical outcomes of fluoroscopic removal of retrievable self-expandable metal stents (SEMSs) for malignant oesophageal strictures, to compare clinical outcomes of three different removal techniques, and to identify predictive factors of successful removal by the standard technique (primary technical success). A total of 137 stents were removed from 128 patients with malignant oesophageal strictures. Primary overall technical success and removal-related complications were evaluated. Logistic regression models were constructed to identify predictive factors of primary technical success. Primary technical success rate was 78.8 % (108/137). Complications occurred in six (4.4 %) cases. Stent location in the upper oesophagus (P=0.004), stricture length over 8 cm (P=0.030), and proximal granulation tissue (Pstent location in the upper oesophagus, and stricture length over 8 cm were negative predictive factors for primary technical success by standard extraction and may require a modified removal technique. • Fluoroscopic retrievable SEMS removal is safe and effective. • Standard removal technique by traction is effective in the majority of patients. • Three negative predictive factors of primary technical success were identified. • Caution should be exercised during the removal in those situations. • Eversion technique is effective in cases of proximal granulation tissue.

Predictors of Complications and Mortality in Patients with Self-Expanding Metallic Stents for the Palliation of Malignant Colonic Obstruction

Science.gov (United States)

Sousa, Mafalda; Pinho, Rolando; Proença, Luísa; Silva, Joana; Ponte, Ana; Rodrigues, Jaime; Carvalho, João

2017-01-01

Introduction Self-expanding metallic stents (SEMS) for palliative purposes in malignant colonic obstruction are an alternative to surgery that has gained popularity over time. Methods We performed a retrospective study of patients submitted to SEMS for palliation of obstructing malignant colorectal cancer from 2005 to 2015 to evaluate predictive clinical factors for complications and mortality. Results Forty-five patients with high rates of technical and clinical success were included (97.8 and 95.6%, respectively), with complications occurring in 17.8% (8.9% perforations, 4.4% obstructions, and 4.4% migrations). The length of the stenosis was superior in patients with complications (p = 0.01); 11.1% of patients had a re-intervention (2.2% surgery and 8.9% placement of another SEMS). Relief of obstruction without intervention was maintained until death in 77.8% of patients and in 81.4% of patients who had immediate clinical success. The mortality rate was 37.2% at 30 days, 56.5% at 60 days, and 87.5% at 1 year. There were no predictors of survival identified, including age, sex, tumor stage, metastasis, or complications of the procedure. Discussion and Conclusions In this study, SEMS placement was associated with a high rate of technical and clinical success and a low rate of complications, being an option to palliate patients with obstructive neoplasia. The length of the stenosis was associated with a greater risk of complications. The majority of stent-related complications can be managed successfully without surgery. PMID:28848796

Performance evaluation of intermediate cover soil barrier for removal of heavy metals in landfill leachate.

Science.gov (United States)

Suzuki, Kazuyuki; Anegawa, Aya; Endo, Kazuto; Yamada, Masato; Ono, Yusaku; Ono, Yoshiro

2008-11-01

This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces.

Partially Covered Metal Stents May Not Prolong Stent Patency Compared to Uncovered Stents in Unresectable Malignant Distal Biliary Obstruction

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Kim, Jae Yun; Ko, Gyu Bong; Lee, Tae Hoon; Park, Sang-Heum; Lee, Yun Nah; Cho, Young Sin; Jung, Yunho; Chung, Il-Kwun; Choi, Hyun Jong; Cha, Sang-Woo; Moon, Jong Ho; Cho, Young Deok; Kim, Sun-Joo

2017-01-01

Background/Aims Controversy still exists regarding the benefits of covered self-expandable metal stents (SEMSs) compared to uncovered SEMSs. We aimed to compare the patency and stent-related adverse events of partially covered SEMSs (PC-SEMSs) and uncovered SEMSs in unresectable malignant distal biliary obstruction. Methods A total of 134 patients who received a PC-SEMS or uncovered SEMS for palliation of unresectable malignant distal biliary obstruction were reviewed retrospectively. The main outcome measures were stent patency, stent-related adverse events, and overall survival. Results The median stent patency was 118 days (range, 3 to 802 days) with PC-SEMSs and 105 days (range, 2 to 485 days) with uncovered SEMSs (p=0.718). The overall endoscopic revision rate due to stent dysfunction was 36.6% (26/71) with PC-SEMSs and 36.5% (23/63) with uncovered SEMSs (p=0.589). Tumor ingrowth was more frequent with uncovered SEMSs (4.2% vs 19.1%, p=0.013), but migration was more frequent with PC-SEMSs (11.2% vs 1.5%, p=0.04). The incidence of stent-related adverse events was 2.8% (2/71) with PC-SEMSs and 9.5% (6/63) with uncovered SEMSs (p=0.224). The median overall survival was 166 days with PC-SEMSs and 168 days with uncovered SEMSs (p=0.189). Conclusions Compared to uncovered SEMSs, PC-SEMSs did not prolong stent patency in unresectable malignant distal biliary obstruction. Stent migration was more frequent with PC-SEMSs. However, tumor ingrowth was less frequent with PC-SEMSs compared to uncovered SEMSs. PMID:28208003

Self-expandable nitinol stent placement in homocysteinemic porcine aorta

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Luís Henrique Gil França

2008-01-01

Full Text Available PURPOSE: To compare aortic intimal thickening of normal and hyperhomocysteinemic pigs (induced with a methionine-rich diet following placement of a self-expanding nitinol stent. METHODS: Eighteen Macau pigs were used. They were older than eight weeks in age and had an average weight of 30 kg. Pigs were randomly divided into two groups. The first, Group C (control, was fed a regular diet, and the second group, Group M, was fed a methionine-rich diet for 30 days to induce hyperhomocysteinemia. The self-expandable nitinol stents were 25mm in length and 8 mm in diameter after expansion. Blood samples were collected to measure total cholesterol, triglycerides, HDL and homocysteine concentrations. All animals were subjected to angiography. Thirty days after the procedure, the animals were sacrificed, and the abdominal aorta was removed for histological and digital morphometry analysis. RESULTS: Under microscopic evaluation, the intima was significantly thicker in Group C than in Group M. When groups were compared by digital morphometric analysis, intimal thickening of the vessel wall was higher in Group C than in Group M. There was no significant change in total cholesterol, triglycerides or HDL concentrations in either group. In group C the levels of plasma homocysteine ranged from 14,40 to 16,73µmol/l; in Group M, plasma homocysteine levels ranged from 17.47 to 59.80 µmol/l after 30 days of a methionine-rich diet. CONCLUSION: Compared to normal pigs, less intimal hyperplasia was observed in the abdominal aortas of hyperhomocysteinemic pigs thirty days after the insertion of a self-expandable nitinol stent.

Temporary urethral covered stent - third year of experience

International Nuclear Information System (INIS)

Stojanovis, V.; Maksimovis, H.; Markovis, B.; Markovis, Z.

2006-01-01

Full text: In October 2003, a new generation of urethral stents ALLIUM, produced in Israel, were used at the Department of Interventional Radiology, CCS, in 18 patients with chronic stricture of bulbar urethra. The indications for insertion were determined according to well-known and recognized therapeutical protocols. The stent is made of nitinol wire with polyurethane cover. It is inserted under local anesthesia by a special self-expandable system that may be fixed or flexible. The stents we used were 3-6 cm long and 28 Fr wide. Radioscopic-assisted insertion was performed over formerly placed metal guide. Prior to insertion, balloon-catheter dilatation of stricture matching the stent width was carried out. Pre-insertion urethrotomy was performed in one case. The insertion technique is simple, presupposing the knowledge of older generations of techniques of urethral dilatation and insertion of self-expandable stents. The follow-up of results was done according to a priori established protocol including the following: UCG, uroflowmetry and interview with patients. Due to stent migration, the 'stent over stent' technique was applied in one case, while reposition by balloon-catheter outward traction was performed in two cases of caudal migration. No irritative discomforts were reported in the first 4 months after stent dwelling. Uroflowmetric controls verified at least four times better results than before the insertion. Given it is the question of covered stent, there is no possibility of proliferative secondary lumen obstruction. On account of soft structure and conic shape of posterior part of stent, no lesions of the external urethral sphincter were manifested. The stent is simply withdrawn after 6 months by outward traction using the forceps at the time when the stent construction turns into soft and straight wire. The first clinical experiences are very favorable and ALLIUM stent may be expected to be the stent of choice for chronic bulbar strictures

Impact of Carcinomatosis on Clinical Outcomes after Self-Expandable Metallic Stent Placement for Malignant Gastric Outlet Obstruction.

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Ji Eun Lee

Full Text Available It is still unclear whether the peritoneal carcinomatosis had a negative effect on the clinical outcomes of patients who underwent self-expandable metallic stent (SEMS placement for malignant gastric outlet obstruction (GOO. Although carcinomatosis may be associated with the development of multifocal gastrointestinal (GI tract obstruction or decreased bowel movement, previous studies investigated the occurrence of stent failure only and thus had limitation in evaluating clinical outcomes of patients with carcinomatosis.Between 2009 and 2013, 155 patients (88 patients without carcinomatosis and 67 patients with carcinomatosis underwent endoscopic SEMS placement for malignant GOO. Factors affecting clinical success and obstructive symptom-free survival (time period between SEMS placement and the recurrence of obstructive symptoms due to multifocal GI tract obstruction or decreased bowel movement as well as stent failure were assessed.Patients with carcinomatosis showed higher Eastern Cooperative Oncology Group (ECOG scale than those without carcinomatosis. Clinical success rates were 88.1% in patients with carcinomatosis and 97.7% in patients without carcinomatosis. In multivariate analysis, only ECOG scale was identified as an independent predictor of clinical success. During follow-up period, patients with carcinomatosis showed significantly shorter obstructive symptom-free survival than those without carcinomatosis. In multivariate analysis, the presence of carcinomatosis, chemotherapy or radiation therapy after SEMS placement, and obstruction site were identified as independent predictors of obstructive symptom-free survival. For patient without carcinomatosis, stent failure accounted for the recurrence of obstructive symptoms in 84.6% of cases. For patients with carcinomatosis, multifocal GI tract obstruction or decreased bowel movement accounted for 37.9% of cases with obstructive symptom recurrence and stent failure accounted for 44.8% of

Chinese IP expands with self-reliance.

Science.gov (United States)

1999-05-01

In 1999, program officers from JOICFP visited five of 10 projects where JOICFP has provided direct assistance during 1993-95 to enhance health education in China's integrated family planning, maternal-child health programs. The JOICFP team and three members of the Chinese National Steering Committee of the Integrated Projects visited project areas in remote and mountainous areas that are characterized by underdevelopment, low income rates, low rates of hospital deliveries, and high rates of parasitic infection. The monitoring team found that all project areas continued the projects after completion of the 3-year period and even expanded efforts to cover other areas. By 1998, more than a million people had been served, which is quadruple the initial target number. The team found that the program could benefit from additional assistance in training new staff to interact with the public and to use IEC (information, education, communication) materials appropriately. One project area, Shaowu City, opened a new Family Health Service Center in August 1998 with a grant from the Japanese Grant Assistance for Grassroots Projects and assistance from its provincial and local government. This Center serves women and children and adolescents on a fee-charged basis and hopes to expand its service area.

Interaction of Electromagnetic Waves with Two-Dimensional Metal Covered with Radar Absorbing Material and Plasma

International Nuclear Information System (INIS)

Lan Chaohui; Hu Xiwei; Jiang Zhonghe

2008-01-01

A two-dimensional metal model is established to investigate the stealth mechanisms of radar absorbing material (RAM) and plasma when they cover the model together. Using the finite-difference time-domain (FDTD) method, the interaction of electromagnetic (EM) waves with the model can be studied. In this paper, three covering cases are considered: a. RAM or plasma covering the metal solely; b. RAM and plasma covering the metal, while plasma is placed outside; c. RAM and plasma covering the metal, while RAM is placed outside. The calculated results show that the covering order has a great influence on the absorption of EM waves. Compared to case a, case b has an advantage in the absorption of relatively high-frequency EM waves (HFWs), whereas case c has an advantage in the absorption of relatively low-frequency EM waves (LFWs). Through the optimization of the parameters of both plasma and RAM, it is hopeful to obtain a broad absorption band by RAM and plasma covering. Near-field attenuation rate and far-field radar cross section (RCS) are employed to compare the different cases. (low temperature plasma)

Sealing of Airway Fistulas for Metallic Covered Z-type Stents

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Hongwu WANG

2011-08-01

Full Text Available Background and objective Treating airway fistulas, including esophagorespiratory fistulas (ERFs, bronchopleural fistulas (BPFs, and tracheomediastinal fistulas (TMFs, is difficult. The aim of this study is to evaluate the safety and clinical efficacy of metallic covered Z-type stents (CZTS for the treatment of airway fistulas through bronchoscopy or fluroscopy. Methods Thirty-eight patients with fistulas between the esophagus, mediastina, and airways (32 ERFs, 5 BPFs, and 1 TMF were retrospectively reviewed after treatment with covered metallic esophageal and airway stents. The fistulas were caused by esophageal (n=26, bronchogenic (n=11, and thyroid (n=1 carcinomas. Results Forty-six fistulas were found in 38 patients. The fistula size ranged from 0.5 cm to 7.0 cm. Forty airway covered metal stents (24 Y-type, 8 L-type, and 8 I-type and 24 esophageal metal stents were placed. Complete responses to the sealing effects of fistulas were noted in 4.3% of all the fistulas, 60.9% showed complete clinical responses, 23.9% showed partial responses, and 10.9% showed no response. An effectivity rate of 89.1% was observed, and the median survival duration of all patients was 5 months. Conclusion The use of CZTS appears to be safe and feasible for the palliative treatment of ERFs, BPFs, and TMFs. Airway stent placement is recommended for patients with ERF. In the event that airway stents fail, esophageal stents should be given. Airway bifurcation stents were observed to be especially suitable for the sealing of fistulas near the trachea carina.

Comparative Study of Esophageal Self-expandable Metallic Stent Insertion and Gastrostomy Feeding for Dysphagia Caused by Lung Cancer.

Science.gov (United States)

Kim, Jihye; Min, Yang Won; Lee, Hyuk; Min, Byung Hoon; Lee, Joon Haeng; Rhee, Poong Lyul; Kim, Jae J

2018-03-25

Dysphagia is encountered in a large proportion of patients with lung cancer and is associated with malnutrition and a poor quality of life. This study compared the clinical outcomes of self-expandable metallic stent (SEMS) insertion and percutaneous gastrostomy (PG) feeding for patients with lung cancer and dysphagia. A total of 261 patients with lung cancer, who underwent either SEMS insertion (stent group) or PG (gastrostomy group) as an initial treatment procedure for dysphagia between July 1997 and July 2015 at the Samsung Medical Center, were reviewed retrospectively, and 84 patients with esophageal obstruction were identified. The clinical outcomes, including the overall survival, additional intervention, complications, and post-procedural nutritional status in the two groups, were compared. Among the 84 patients finally analyzed, 68 patients received SEMS insertion and 16 had PG. The stent group had less cervical obstruction and more mid-esophageal obstruction than the gastrostomy group. The Kaplan-Meier curves revealed similar overall survival in the two groups. Multivariate analysis showed that the two modalities had similar survival rates (PG compared with SEMS insertion, hazard ratio 0.682, p=0.219). Fifteen patients (22.1%) in the stent group received additional intervention, whereas there was no case in the gastrostomy group (p=0.063). The decrease in the serum albumin level after the procedure was lower in the gastrostomy group than in the stent group (-0.20±0.54 g/dL vs. -0.65±0.57 g/dL, p=0.013). SEMS insertion and PG feeding for relieving dysphagia by lung cancer had a comparable survival outcome. On the other hand, PG was associated with a better nutritional status.

Self-organization in metal complexes

International Nuclear Information System (INIS)

Radecka-Paryzek, W.

1999-01-01

Inorganic self-organization involves the spontaneous generation of well-defined supramolecular architectures from metal ions and organic ligands. The basic concept of supramolecular chemistry is a molecular recognition. When the substrate are metal ions, recognition is expressed in the stability and selectivity of metal ion complexation by organic ligands and depends on the geometry of the ligand and on their binding sites that it contains. The combination of the geometric features of the ligand units and the coordination geometries of the metal ions provides very efficient tool for the synthesis of novel, intriguing and highly sophisticated species such as catenanes, box structures, double and triple helicates with a variety of interesting properties. The article will focus on the examples of inorganic self-organization involving the templating as a first step for the assembly of supramolecular structures of high complexity. (author)

Comparison between the STENTYS self-apposing bare metal and paclitaxel-eluting coronary stents for the treatment of saphenous vein grafts (ADEPT trial)

NARCIS (Netherlands)

A.J.J. IJsselmuiden (Alexander); C. Simsek (Cihan); Van Driel, A.G. (A. G.); Bouchez, D. (D.); G. Amoroso (Giovanni); P. Vermeersch (Paul); Karjalainen, P.P. (P. P.)

2018-01-01

textabstractAims To describe the safety and performance of STENTYS self-expandable bare metal stents (BMS) versus paclitaxel-eluting stents (PES) in saphenous vein grafts (SVGs). Methods and Results A randomised controlled trial was performed in four hospitals in three European countries between

Outcome and risk factors assessment for adverse events in advanced esophageal cancer patients after self-expanding metal stents placement.

Science.gov (United States)

Rodrigues-Pinto, E; Pereira, P; Coelho, R; Andrade, P; Ribeiro, A; Lopes, S; Moutinho-Ribeiro, P; Macedo, G

2017-02-01

Self-expanding metal stents (SEMS) are the treatment of choice for advanced esophageal cancers. Literature is scarce on risk factors predictors for adverse events after SEMS placement. Assess risk factors for adverse events after SEMS placement in advanced esophageal cancer and evaluate survival after SEMS placement. Cross-sectional study of patients with advanced esophageal cancer referred for SEMS placement, during a period of 3 years. Ninety-seven patients with advanced esophageal cancer placed SEMS. Adverse events were more common when tumors were located at the level of the distal esophagus/cardia (47% vs 23%, P = 0.011, OR 3.1), with statistical significance being kept in the multivariate analysis (OR 3.1, P = 0.018). Time until adverse events was lower in the tumors located at the level of the distal esophagus/cardia (P = 0.036). Survival was higher in patients who placed SEMS with curative intent (327 days [126-528] vs. 119 days [91-147], P = 0.002) and in patients submitted subsequently to surgery compared with those who did just chemo/radiotherapy or who did not do further treatment (563 days [378-748] vs. 154 days [133-175] vs. 46 days [20-72], P dysphagia in advanced esophageal cancer and are associated with an increased out-of-hospital survival, as long as there are conditions for further treatments. Tumors located at the level of the distal esophagus/cardia are associated with a greater number of adverse events, which also occur earlier. © 2016 International Society for Diseases of the Esophagus.

Risk factors for technical failure of endoscopic double self-expandable metallic stent placement by partial stent-in-stent method.

Science.gov (United States)

Kawakubo, Kazumichi; Kawakami, Hiroshi; Toyokawa, Yoshihide; Otani, Koichi; Kuwatani, Masaki; Abe, Yoko; Kawahata, Shuhei; Kubo, Kimitoshi; Kubota, Yoshimasa; Sakamoto, Naoya

2015-01-01

Endoscopic double self-expandable metallic stent (SEMS) placement by the partial stent-in-stent (PSIS) method has been reported to be useful for the management of unresectable hilar malignant biliary obstruction. However, it is technically challenging, and the optimal SEMS for the procedure remains unknown. The aim of this study was to identify the risk factors for technical failure of endoscopic double SEMS placement for unresectable malignant hilar biliary obstruction (MHBO). Between December 2009 and May 2013, 50 consecutive patients with MHBO underwent endoscopic double SEMS placement by the PSIS method. We retrospectively evaluated the rate of successful double SEMS placement and identified the risk factors for technical failure. The technical success rate for double SEMS placement was 82.0% (95% confidence interval [CI]: 69.2-90.2). On univariate analysis, the rate of technical failure was high in patients with metastatic disease and unilateral placement. Multivariate analysis revealed that metastatic disease was a significant risk factor for technical failure (odds ratio: 9.63, 95% CI: 1.11-105.5). The subgroup analysis after double guidewire insertion showed that the rate of technical success was higher in the laser-cut type SEMS with a large mesh and thick delivery system than in the braided type SEMS with a small mesh and thick delivery system. Metastatic disease was a significant risk factor for technical failure of double SEMS placement for unresectable MHBO. The laser-cut type SEMS with a large mesh and thin delivery system might be preferable for the PSIS procedure. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Primary Self-Expandable Nitinol Stent Placement in Focal Lesions of Infrarenal Abdominal Aorta: Long Term Results

International Nuclear Information System (INIS)

Lastovickova, Jarmila; Peregrin, Jan H.

2008-01-01

Purpose. To evaluate the technical and clinical success, safety and long term results of percutaneous transluminal angioplasty/self-expandable nitinol stent placement of infrarenal abdominal aorta focal lesions. Materials and Methods. Eighteen patients underwent PTA of focal atherosclerotic occlusive disease of distal abdominal aorta. Two symptomatic occlusions and 16 stenoses in 10 male and 8 female patients (mean age 68.2 years) were treated with primary self-expandable nitinol stent placement. Results. Primary self-expandable nitinol stent placement was technically successful in all 18 procedures; clinical success was achieved in 100% of patients. No complications associated with the procedure occurred. During the 49.4 months of mean follow up (range 3-96, 4 months) all treated aortic segments remained patent. Conclusions. Endovascular treatment (primary self-expandable nitinol stent placement) of focal atherosclerotic lesions of distal abdominal aorta is a safe method with excellent primary technical and clinical success rates and favourable Long term results

The trend of indexed papers in PubMed covering different aspects of self-immolation.

Science.gov (United States)

Rezaeian, Mohsen

2014-01-01

Self-immolation is a fatal and devastating method of committing suicide used around the world. The chief aim of the present article is to look at the trend of indexed papers in PubMed covering different aspects of self-immolation. PubMed search engine (http://www.ncbi.nlm.nih.gov) was searched by using six keywords i.e. "self-immolation", "self-inflicted burn", "self-burning", "self-incineration", "suicidal burns" and "suicide by burning". These keywords should appear either in the title or the abstract of the articles. The time frame was set as to retrieve papers expanding from early indexing time up to end of the year 2011. Based on the search strategy 132 papers were retrieved from these total numbers; 12 (9%) were categorized as review papers; 24 (18%) as case reports and the rest 96 (73%) were original studies. It seems that the number of papers increased during the years of investigations and the highest indexed papers i.e. 14 (10.6%) belonged to the year 2011. While most journals, published only one article the highest indexed papers i.e. 35 (26.5%) belonged to Burns. There was an increasing trend in the number of self-immolation articles indexed in PubMed since 1965. Three journals i.e. Burns, Journal of Burn Care and Rehabilitation and Journal of Forensic Sciences hosted for more than 37% of all those indexed articles. However, given the increasing trend of self-immolation still more studies are needed to shed light on the diverse aspects of this appalling human behavior.

Afterloading intracavitary irradiation and expanding stent for malignant biliary obstruction

Energy Technology Data Exchange (ETDEWEB)

Yoshimura, Hitoshi; Sakaguchi, Hiroshi; Yoshioka, Tetsuya and others

1989-02-01

A double lumen catheter was developed as an apllicator for the remote afterloading (RALS) of /sup 60/Co source for the intracavitary irradiation of an obstructed common bile duct caused by carcinoma of the gallbladder. This was followed by the placement of nylon-covered expandable metallic stents to maintain patency. This combination effectively provided palliation. (author).

A self-adjusting expandable GPS collar for male elk

Science.gov (United States)

Brian L. Dick; Scott L. Findholt; Bruce K. Johnson

2013-01-01

It is a challenge to use collars on male cervids because their neck size can increase substantially during the rut and also because of growth as the animal matures. We describe how to build a self-adjusting expandable collar for yearling or adult male Rocky Mountain elk (Cervus elaphus) to which very high frequency transmitters and global...

Expandable metal stents for tracheal obstruction: permanent or temporary? A cautionary tale.

OpenAIRE

Hind, C R; Donnelly, R J

1992-01-01

An expandable metal stent inserted via a long term tracheostomy successfully relieved life threatening respiratory obstruction due to benign tracheal stenosis. Later the patient's tracheostomy suction catheter became stuck on the stent and dislodged it. The stent was removed electively, without damaging the trachea, with a rigid biopsy forceps.

Self-expanding nanoplatinum-coated nitinol devices for atrial septal defect and patent ductus arteriosus closure: a swine model.

Science.gov (United States)

Lertsapcharoen, Pornthep; Khongphatthanayothin, Apichai; La-orkhun, Vidhavas; Supachokchaiwattana, Pentip; Charoonrut, Phingphol

2006-01-01

Our purpose was to evaluate self-expanding nanoplatinum-coated nitinol devices for transcatheter closure of atrial septal defects and patent ductus arteriosus in a swine model. The devices were braided from platinum-activated nitinol wires and filled with polyester to enhance thrombogenicity. The platinum activation of the nitinol wires was carried out with the help of Nanofusion technology. The coating of platinum covers the exposed surface of the nitinol wires and prevents the release of nickel into the blood stream after the implantation of the device but does not affect its shape memory, which makes the device self-expanding after it is loaded from the catheter. Atrial septal defects were created in 12 piglets by balloon dilation of the patent foramen ovale. The size of the device was selected on the basis of the diameter of the balloon and the size of the defect, measured by transthoracic echocardiography. The devices were successfully deployed in all 12 piglets under fluoroscopic study. Transthoracic color Doppler echocardiograms showed complete closure of the atrial septal defect within 15 minutes of device implantation. Twelve patent ductus arteriosus closure devices were deployed in the right or left subclavian arteries in 10 piglets. Angiograms showed complete occlusion of the subclavian arteries within a few minutes of device deployment. In the atrial septal defect cases, the autopsy findings showed complete organizing fibrin thrombus formation and complete neo-endothelialization on the outer surface of the devices within one week and six weeks of implantation, respectively. The use of self-expanding nanoplatinum-coated nitinol devices for the transcatheter closure of atrial septal defects and patent ductus arteriosus is feasible. The excellent occlusion result and complete neo-endothelialization of the devices in the swine model is an indication of the potential of these devices in human application.

Self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty

International Nuclear Information System (INIS)

Tepe, Gunnar; Heller, Stephan; Wiskirchen, Jakub; Fischmann, Arne; Claussen, Claus D.; Zeller, Thomas; Coerper, Stephan; Beckert, Stefan; Balletshofer, Bernd

2007-01-01

The feasibility of self-expanding nitinol stents for treatment of infragenicular arteries following unsuccessful balloon angioplasty was assessed. Options for lower limb percutaneous revascularization are limited, especially for complex vessel obstruction. Depending on the lesion and the experience of the interventionalist, the failure rate of balloon angioplasty (PTA) ranges between 10 and 40%. Until recently, no self-expanding stent for the use in the infragenicular arteries was available. This is the first report of the results for 18 consecutive patients who received 4F sheath compatible self-expanding nitinol stents following unsuccessful PTA or early restenosis. Twenty-four stents were implanted in 21 lesions for various indications residual stenosis >50% due to heavy calcification, flow-limiting dissection, occluding thrombus resistant to thrombolyis, thrombaspiration, and PTA, and early restenosis after previous PTA. Stent implantation was feasible in all cases. No complications occurred. After the stent implantation, all primarily unsuccessful interventions could be transformed into successful procedures with no residual stenosis >30% in any case. After 6 ± 2 months, two of the 18 patients died, and 14 of the 16 remaining patients improved clinically. At follow-up, the patency could be assessed in 14 stented arteries. Three stents were occluded, one stent showed some neointimal hyperplasia (50-70% restenosis), the remaining ten stents showed no restenosis (0-30%). The use of self-expanding nitinol stents in tibioperoneal and popliteal arteries is a safe and feasible option for the treatment of unsuccessful PTA. The 6-months patency is high. (orig.)

Use of fully covered self-expanding metal stents for the management of benign biliary conditions Utilización de prótesis metálicas autoexpandibles totalmente recubiertas en procesos biliares benignos

Directory of Open Access Journals (Sweden)

J. García-Cano

2010-09-01

Full Text Available Background and aim: biliary self-expanding metal stents (SEMS have the advantage of being inserted undeployed with very small sizes and provide, when fully opened, large diameters for biliary drainage. However, their use in benign conditions has been very limited, mainly because of difficulty in their extraction. We present our initial experience with a fully covered SEMS (Wallflex for the management of benign problems of the bile duct. Patients and methods: in a prospective study, stents of 8 mm in diameter and 4, 6 or 8 cm long were inserted by means of ERCP. These SEMS were chosen when according to medical judgement it was thought that diameters greater than 10 French (3.3 mm were needed for proper biliary drainage. Stents were extracted also endoscopically, several months later when deemed clinically appropriate. Results: twenty biliary SEMS were inserted. Reasons for insertion were: large intrahepatic biliary fistula after hydatid cyst surgery (1, perforation of the papillary area following endoscopic sphincterotomy (2, coaxial insertion to achieve patency in obstructed uncovered stents inserted in benign conditions (3, benign strictures (7, multiple and large common bile duct stones that could not be extracted because of tapering and stricturing of the distal common bile duct (7. In all cases, successful biliary drainage was achieved and there were no complications from insertion. Stents were easily extracted after a mean time of 132 days (36-270 in place. Complete resolution of biliary problems was obtained in 14 patients (70%. Conclusions: in our initial experience, the fully covered Wallflex biliary stent was removed without any complication after being in place in the common bile duct for a mean time of over four months. Therefore, it could be used in the management of benign biliary conditions.Introducción y objetivo: las prótesis metálicas autoexpandibles biliares (PMAB tienen la ventaja de introducirse plegadas con calibres muy

The use of expandable metallic airway stents for tracheobronchial obstruction in children.

Science.gov (United States)

Filler, R M; Forte, V; Fraga, J C; Matute, J

1995-07-01

Expandable metallic angioplasty stents (Palmaz stent) have been implanted in the trachea and/or bronchi of seven children. Three children had severe tracheal stenosis after tracheoplasty for congenital tracheal stenosis repair, and four had tracheomalacia or bronchomalacia with or without vascular compression. The mean age at stenting was 9.7 months (range, 2 to 15 months). Balloon expandable stents were inserted into the trachea or bronchus through a 3.5-mm bronchoscope under fluoroscopic control. Initially a single tracheal stent was used for all patients except for one with obstruction in the trachea and both bronchi, in whom three stents were implanted. Three children had recurrent airway obstruction 1 month later; one was cured with a second stent; one child died 1 year later; and the other is being treated for heart disease. The others have no serious respiratory problems. The stents in all have been in place for 1 to 25 (mean, 11) months. No immediate complications were noted. Early and late bronchoscopy showed incomplete epithelialization of the stent and patches of granulation tissue on it. Two stents were removed bronchoscopically, one at the completion of treatment for tracheomalacia and the other at the time of recurrent airway obstruction. This preliminary experience indicates that expandable metallic stents have a useful role in the treatment of selected lower airway obstructions.

The study of metal stents for effect to the radiation therapy

International Nuclear Information System (INIS)

Gao Li; Feng Ningyuan; Zhai Renyou; Yang Weizhi; Xu Guozhen; Wang Yafei

2001-01-01

Objective: To confirm whether the metal stents affect the radiation beam. Methods: The transmission factors from the national self-expanding esophagus stent, stainless self-expanding bile duct stent, and balloon-expanded vascular stent was supervised under 192 Ir irradiation in the air. Results: The transmission factors from the 3 kinds of metal stents were 0.993, 0.988, and 0.997, which meant that the attenuation of the stents to the radiation was 0.7%, 1.2%, and 0.3%, respectively (mean: 0.7%). Conclusion: The effect of the metal stents to the radiation was less than 1.2% and that meant there was no clinical significant effect on the patients irradiated following stent implantation or to perform the intra-stents brachytherapy

Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

Energy Technology Data Exchange (ETDEWEB)

Kim, Charles Y., E-mail: charles.kim@duke.edu; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P. [Duke University Medical Center, Division of Vascular and Interventional Radiology (United States)

2012-08-15

Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

International Nuclear Information System (INIS)

Kim, Charles Y.; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P.

2012-01-01

Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

Self-healing cable for extreme environments

Science.gov (United States)

Huston, Dryver R. (Inventor); Tolmie, Bernard R. (Inventor)

2009-01-01

Self-healing cable apparatus and methods disclosed. The self-healing cable has a central core surrounded by an adaptive cover that can extend over the entire length of the self-healing cable or just one or more portions of the self-healing cable. The adaptive cover includes an axially and/or radially compressible-expandable (C/E) foam layer that maintains its properties over a wide range of environmental conditions. A tape layer surrounds the C/E layer and is applied so that it surrounds and axially and/or radially compresses the C/E layer. When the self-healing cable is subjected to a damaging force that causes a breach in the outer jacket and the tape layer, the corresponding localized axially and/or radially compressed portion of the C/E foam layer expands into the breach to form a corresponding localized self-healed region. The self-healing cable is manufacturable with present-day commercial self-healing cable manufacturing tools.

A new self-expandable aortic valved stent deployed above native leaflets for aortic insufficiency: an in vitro study.

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Huang, H; Zhou, Y; Shao, J; Cai, J; Mei, Y; Wang, Y

2012-12-01

The aim of this paper was to develop a new self-expandable aortic valved stent following the shape of the sinus of Valsalva, which can be deployed above native leaflets for aortic regurgitation, and study it's effect on coronary artery flow when orthotopic implantation in and above native leaflets. New self-expandable aortic valved stent consist of nitinol stent and bovine pericardium, and was designed following the shape of the sinus of Valsalva, the bovine pericardium was tailed as native leaflet. Thirty-six swine hearts were divided into three equal groups of twelve. In Group A (N.=12), the new self-expandable aortic valved stents deployed in native leaflets. In Group B (N.=12), the new self-expandable aortic valved stents deployed above native leaflets. In Group C (N.=12), the cylinder-like valved stents deployed only in native leaflets. The measurements of each coronary flow rate and endoscopic inspections were repeated post-implantation. In Group A and C, valve implantation in native leaflets resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after new self-expandable aortic valved stent placement. Endoscopic inspections showed that in group A and C the native leaflets sandwiched between valved stent and aortic wall, whereas, in group B the native leaflets were under the artificial leaflets. Two kinds of stents deployed in native leaflets affect left and right coronary flows significantly. No significant effect was found when the new self-expandable aortic valved stent deployed above native leaflets. This new self-expandable aortic valved stent can be deployed above the native leaflets, which avoids the obstruction of native leaflets on coronary flow.

Modeling of the metallic port in breast tissue expanders for photon radiotherapy.

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Yoon, Jihyung; Xie, Yibo; Heins, David; Zhang, Rui

2018-03-30

The purpose of this study was to model the metallic port in breast tissue expanders and to improve the accuracy of dose calculations in a commercial photon treatment planning system (TPS). The density of the model was determined by comparing TPS calculations and ion chamber (IC) measurements. The model was further validated and compared with two widely used clinical models by using a simplified anthropomorphic phantom and thermoluminescent dosimeters (TLD) measurements. Dose perturbations and target coverage for a single postmastectomy radiotherapy (PMRT) patient were also evaluated. The dimensions of the metallic port model were determined to be 1.75 cm in diameter and 5 mm in thickness. The density of the port was adjusted to be 7.5 g/cm 3 which minimized the differences between IC measurements and TPS calculations. Using the simplified anthropomorphic phantom, we found the TPS calculated point doses based on the new model were in agreement with TLD measurements within 5.0% and were more accurate than doses calculated based on the clinical models. Based on the photon treatment plans for a real patient, we found that the metallic port has a negligible dosimetric impact on chest wall, while the port introduced significant dose shadow in skin area. The current clinical port models either overestimate or underestimate the attenuation from the metallic port, and the dose perturbation depends on the plan and the model in a complex way. TPS calculations based on our model of the metallic port showed good agreement with measurements for all cases. This new model could improve the accuracy of dose calculations for PMRT patients who have temporary tissue expanders implanted during radiotherapy and could potentially reduce the risk of complications after the treatment. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Transcatheter aortic-valve replacement with a self-expanding prosthesis.

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Adams, David H; Popma, Jeffrey J; Reardon, Michael J; Yakubov, Steven J; Coselli, Joseph S; Deeb, G Michael; Gleason, Thomas G; Buchbinder, Maurice; Hermiller, James; Kleiman, Neal S; Chetcuti, Stan; Heiser, John; Merhi, William; Zorn, George; Tadros, Peter; Robinson, Newell; Petrossian, George; Hughes, G Chad; Harrison, J Kevin; Conte, John; Maini, Brijeshwar; Mumtaz, Mubashir; Chenoweth, Sharla; Oh, Jae K

2014-05-08

We compared transcatheter aortic-valve replacement (TAVR), using a self-expanding transcatheter aortic-valve bioprosthesis, with surgical aortic-valve replacement in patients with severe aortic stenosis and an increased risk of death during surgery. We recruited patients with severe aortic stenosis who were at increased surgical risk as determined by the heart team at each study center. Risk assessment included the Society of Thoracic Surgeons Predictor Risk of Mortality estimate and consideration of other key risk factors. Eligible patients were randomly assigned in a 1:1 ratio to TAVR with the self-expanding transcatheter valve (TAVR group) or to surgical aortic-valve replacement (surgical group). The primary end point was the rate of death from any cause at 1 year, evaluated with the use of both noninferiority and superiority testing. A total of 795 patients underwent randomization at 45 centers in the United States. In the as-treated analysis, the rate of death from any cause at 1 year was significantly lower in the TAVR group than in the surgical group (14.2% vs. 19.1%), with an absolute reduction in risk of 4.9 percentage points (upper boundary of the 95% confidence interval, -0.4; P<0.001 for noninferiority; P = 0.04 for superiority). The results were similar in the intention-to-treat analysis. In a hierarchical testing procedure, TAVR was noninferior with respect to echocardiographic indexes of valve stenosis, functional status, and quality of life. Exploratory analyses suggested a reduction in the rate of major adverse cardiovascular and cerebrovascular events and no increase in the risk of stroke. In patients with severe aortic stenosis who are at increased surgical risk, TAVR with a self-expanding transcatheter aortic-valve bioprosthesis was associated with a significantly higher rate of survival at 1 year than surgical aortic-valve replacement. (Funded by Medtronic; U.S. CoreValve High Risk Study ClinicalTrials.gov number, NCT01240902.).

Management of stent dislodgment in coarctoplasty of aorta with three overlapping self-expandable nitinol stents.

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Ghazi, Payam; Haji-Zeinali, Ali-Mohammad

2010-01-01

We describe a case of native coarctation of aorta managed with three self-expandable nitinol stents. After balloon pre-dilation, the first and second stents were dislodged. The coarcted area was successfully treated with the third stent overlapped with the previous stents. During follow up (30 months), the patient was free of complications. It seems that implantation of multiple overlapping self-expandable stents in aortic coarctation patients, if needed, is safe and possible.

Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction.

Science.gov (United States)

Sugimoto, Mitsuru; Takagi, Tadayuki; Suzuki, Rei; Konno, Naoki; Asama, Hiroyuki; Watanabe, Ko; Nakamura, Jun; Kikuchi, Hitomi; Waragai, Yuichi; Takasumi, Mika; Sato, Yuki; Hikichi, Takuto; Ohira, Hiromasa

2017-09-14

To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs). This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups. The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Wing-shaped plastic stents vs. self-expandable metal stents for palliative drainage of malignant distal biliary obstruction: a randomized multicenter study.

Science.gov (United States)

Schmidt, Arthur; Riecken, Bettina; Rische, Susanne; Klinger, Christoph; Jakobs, Ralf; Bechtler, Matthias; Kähler, Georg; Dormann, Arno; Caca, Karel

2015-05-01

Previous studies have shown superior patency rates for self-expandable metal stents (SEMS) compared with plastic stents in patients with malignant biliary obstruction. The aim of this study was to compare stent patency, patient survival, and complication rates between a newly designed, wing-shaped, plastic stent and SEMSs in patients with unresectable, malignant, distal, biliary obstruction. A randomized, multicenter trial was conducted at four tertiary care centers in Germany. A total of 37 patients underwent randomization between March 2010 and January 2013. Patients underwent endoscopic retrograde cholangiography with insertion of either a wing-shaped, plastic stent without lumen or an SEMS.  Stent failure occurred in 10/16 patients (62.5 %) in the winged-stent group vs. 4/18 patients (22.2 %) in the SEMS group (P = 0.034). The median time to stent failure was 51 days (range 2 - 92 days) for the winged stent and 80 days (range 28 - 266 days) for the SEMS (P = 0.002). Early stent failure (stent failure was significantly higher in the winged-stent group compared with the SEMS group. A high incidence of early stent failure within 8 weeks was observed in the winged-stent group. Thus, the winged, plastic stent without central lumen may not be appropriate for mid or long term drainage of malignant biliary obstruction. Study registration ClinicalTrials.gov (NCT01063634). © Georg Thieme Verlag KG Stuttgart · New York.

Novel self-expandable, stent-based transcatheter pulmonic valve: a preclinical animal study.

Science.gov (United States)

Kim, Gi Beom; Lim, Hong-Gook; Kim, Yong Jin; Choi, Eun Young; Kwon, Bo Sang; Jeong, Saeromi

2014-04-15

Because transcatheter implantation of pulmonary valve is indicated for limited-size dysfunctional right ventricular outflow tract only as a balloon-expandable stent, we investigated the feasibility of a large-diameter self-expandable valved stent and the durability of the valve after >6 months. We made a nitinol-wire-based, self-expandable valved stent with leaflets made from porcine pericardium. The porcine pericardium was treated with α-galactosidase, glutaraldehyde, and glycine after decellularization. After cutting the inguinal or cervical area, we implanted a valved stent in 12 sheep through the femoral or jugular vein by using an 18-Fr delivery catheter, controlling the catheter handles and hook block under fluoroscopic and echocardiographic guidance. The mean body weight of sheep was 43.9 kg. We successfully implanted valved stents (diameter: 24 mm in 7 sheep, 26 mm in 5 sheep) in good position in 8 sheep, in the main pulmonary artery (PA) in 2 sheep, and in the right ventricular outlet tract (RVOT) in 2 sheep. We sacrificed 8 sheep (6 sheep in good position, 1 sheep in the main PA, and 1 sheep in the RVOT) after >6 months. Five of the 6 sheep implanted in good position showed well-preserved valve morphology at the time of sacrifice. Histologic findings after routine sacrifice showed well-maintained collagen wave structure and no visible calcification in all explanted valve leaflets. Transcatheter implantation of a nitinol-wire-based, self-expandable valved stent in the pulmonic valve was feasible, and stents implanted in good position showed well-preserved valve leaflets with functional competence in the mid-term results. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Oversizing and Restenosis with Self-Expanding Stents in Iliofemoral Arteries

International Nuclear Information System (INIS)

Saguner, Ardan M.; Traupe, Tobias; Räber, Lorenz; Hess, Nina; Banz, Yara; Saguner, Arhan R.; Diehm, Nicolas; Hess, Otto M.

2012-01-01

Purpose: Uncoated self-expanding nitinol stents (NS) are commonly oversized in peripheral arteries. In current practice, 1-mm oversizing is recommended. Yet, oversizing of NS may be associated with increased restenosis. To provide further evidence, NS were implanted in porcine iliofemoral arteries with a stent-to-artery-ratio between 1.0 and 2.3. Besides conventional uncoated NS, a novel self-expanding NS with an antiproliferative titanium-nitride-oxide (TiNOX) coating was tested for safety and efficacy. Methods: Ten uncoated NS and six TiNOX-coated NS (5–6 mm) were implanted randomly in the iliofemoral artery of six mini-pigs. After implantation, quantitative angiography (QA) was performed for calculation of artery and minimal luminal diameter. Follow-up was performed by QA and histomorphometry after 5 months. Results: Stent migration, stent fracture, or thrombus formation were not observed. All stents were patent at follow-up. Based on the location of the stent (iliac/femoral) and the stent-to-artery-ratio, stent segments were divided into “normal-sized” (stent-to-artery-ratio < 1.4, n = 12) and “oversized” (stent-to-artery-ratio ≥ 1.4, n = 9). All stent segments expanded to their near nominal diameter during follow-up. Normal-sized stent segments increased their diameter by 6% and oversized segments by 29%. A significant correlation between oversizing and restenosis by both angiography and histomorphometry was observed. Restenosis rates were similar for uncoated NS and TiNOX-coated NS. Conclusions: TiNOX-coated NS are as safe and effective as uncoated NS in the porcine iliofemoral artery. All stents further expand to near their nominal diameter during follow-up. Oversizing is linearly and positively correlated with neointimal proliferation and restenosis, which may not be reduced by TiNOX-coating.

Ionic imbalance induced self-propulsion of liquid metals

Science.gov (United States)

Zavabeti, Ali; Daeneke, Torben; Chrimes, Adam F.; O'Mullane, Anthony P.; Zhen Ou, Jian; Mitchell, Arnan; Khoshmanesh, Khashayar; Kalantar-Zadeh, Kourosh

2016-08-01

Components with self-propelling abilities are important building blocks of small autonomous systems and the characteristics of liquid metals are capable of fulfilling self-propulsion criteria. To date, there has been no exploration regarding the effect of electrolyte ionic content surrounding a liquid metal for symmetry breaking that generates motion. Here we show the controlled actuation of liquid metal droplets using only the ionic properties of the aqueous electrolyte. We demonstrate that pH or ionic concentration gradients across a liquid metal droplet induce both deformation and surface Marangoni flow. We show that the Lippmann dominated deformation results in maximum velocity for the self-propulsion of liquid metal droplets and illustrate several key applications, which take advantage of such electrolyte-induced motion. With this finding, it is possible to conceive the propulsion of small entities that are constructed and controlled entirely with fluids, progressing towards more advanced soft systems.

Understanding the self-assembly of proteins onto gold nanoparticles and quantum dots driven by metal-histidine coordination.

Science.gov (United States)

Aldeek, Fadi; Safi, Malak; Zhan, Naiqian; Palui, Goutam; Mattoussi, Hedi

2013-11-26

Coupling of polyhistidine-appended biomolecules to inorganic nanocrystals driven by metal-affinity interactions is a greatly promising strategy to form hybrid bioconjugates. It is simple to implement and can take advantage of the fact that polyhistidine-appended proteins and peptides are routinely prepared using well established molecular engineering techniques. A few groups have shown its effectiveness for coupling proteins onto Zn- or Cd-rich semiconductor quantum dots (QDs). Expanding this conjugation scheme to other metal-rich nanoparticles (NPs) such as AuNPs would be of great interest to researchers actively seeking effective means for interfacing nanostructured materials with biology. In this report, we investigated the metal-affinity driven self-assembly between AuNPs and two engineered proteins, a His7-appended maltose binding protein (MBP-His) and a fluorescent His6-terminated mCherry protein. In particular, we investigated the influence of the capping ligand affinity to the nanoparticle surface, its density, and its lateral extension on the AuNP-protein self-assembly. Affinity gel chromatography was used to test the AuNP-MPB-His7 self-assembly, while NP-to-mCherry-His6 binding was evaluated using fluorescence measurements. We also assessed the kinetics of the self-assembly between AuNPs and proteins in solution, using time-dependent changes in the energy transfer quenching of mCherry fluorescent proteins as they immobilize onto the AuNP surface. This allowed determination of the dissociation rate constant, Kd(-1) ∼ 1-5 nM. Furthermore, a close comparison of the protein self-assembly onto AuNPs or QDs provided additional insights into which parameters control the interactions between imidazoles and metal ions in these systems.

Stent Fracture and Reocclusion After Placement of a Single Self-Expanding Stent in the Common Iliac Artery and Endovascular Treatment

International Nuclear Information System (INIS)

Higashiura, Wataru; Sakaguchi, Shoji; Morimoto, Kengo; Kichikawa, Kimihiko

2008-01-01

We present a case of fracture of a single self-expanding stent placed in the common iliac artery (CIA). An 80-year-old woman underwent placement of a self-expanding stent for CIA occlusion. Stent fracture and reocclusion were detected after 18 months. Successful revascularization was achieved using a stent-in-stent maneuver. The possibility of stent fracture with reocclusion should be considered following treatment with a single self-expanding stent for CIA occlusion.

Calculation of Radioactivity Concentration on Cover Depth of Contaminated Zone for Self-Disposal

Energy Technology Data Exchange (ETDEWEB)

Koo, Daeseo; Sung, Hyun-Hee; Kim, Gye-Nam; Kim, Seung-Soo; Kim, Ilgook; Han, Gyu Seong; Choi, Jong-Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

We have a lot of uranium contaminated soil and concrete wastes owing to dismantlement of uranium conversion facility. There are several radioactive material disposal methods such as regulation exemption, decontamination and long term storage. It is necessary for us to perform permanent disposal of these wastes. To acquire radiation dose under self-disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinectic-electrodialytic. In this study, we evaluated radiation dose on the cover depth of contaminated zone from the wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the wastes of contaminated zone are carried out. The second, the cover depth of contaminated zone are analyzed. The application to self-disposal of contaminated zone are also analyzed. To acquire radiation dose under self-disposal from uranium contaminated soil and concrete wastes, we decontaminated some uranium contaminated soil and concrete wastes using electrokinectic-electrodialytic. To perform self-disposal of the quantity (30,000kg) of contaminated zone, the calculating conditions for radiation dose on the cover depth of contaminated zone are as follows. The area of contaminated zone is 10m{sup 2}. The thickness of contaminated zone is 2 m. The cover depth of contaminated zone are analyzed. The application to self-disposal of contaminated zone are also analyzed. Therefore, as the cover depth increases, the uranium concentration has an increasing trend. It realize that the cover depth of contaminated zone is adequate < 2m at the quantity(30,000kg) of contaminated zone. As the cover depth increases, the uranium concentration has a decreasing trend. As the cover depth increases, the radiation dose(residents) has also a decreasing trend.

Single-step simultaneous side-by-side placement of a self-expandable metallic stent with a 6-Fr delivery system for unresectable malignant hilar biliary obstruction: a feasibility study.

Science.gov (United States)

Kawakubo, Kazumichi; Kawakami, Hiroshi; Kuwatani, Masaki; Kudo, Taiki; Abe, Yoko; Kawahata, Shuhei; Kubo, Kimitoshi; Kubota, Yoshimasa; Sakamoto, Naoya

2015-02-01

Bilateral self-expandable metallic stent (SEMS) placement for the management of unresectable malignant hilar biliary obstruction (UMHBO) is technically challenging to perform using the existing metallic stents with thick delivery systems. The recently developed 6-Fr delivery systems could facilitate a single-step simultaneous side-by-side placement through the accessory channel of the duodenoscope. The aim of this study was to evaluate the feasibility of this procedure. Between May and September 2013, 13 consecutive patients with UMHBO underwent a single-step simultaneous side-by-side placement of SEMS with the 6-Fr delivery system. The technical success rate, stent patency, and rate of complications were evaluated from the prospectively collected database. Technical success was achieved in 11 (84.6%, 95% confidence interval [CI]: 57.8-95.8) patients. The median procedure time was 25 min. Early and late complications were observed in 23% (one segmental cholangitis and two liver abscesses) and 15% (one segmental cholangitis and one cholecystitis) patients, respectively. Median dysfunction free patency was 263 days (95% CI: 37-263). Five patients (38%) experienced stent occlusion that was successfully managed by endoscopic stent placement. A single-step simultaneous side-by-side placement of SEMS with a 6-Fr delivery system was feasible for the management of UMHBO. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Efficacy of Endoscopic Over 3-branched Partial Stent-in-Stent Drainage Using Self-expandable Metallic Stents in Patients With Unresectable Hilar Biliary Carcinoma.

Science.gov (United States)

Uchida, Daisuke; Kato, Hironari; Muro, Shinichiro; Noma, Yasuhiro; Yamamoto, Naoki; Horiguchi, Shigeru; Harada, Ryo; Tsutsumi, Koichiro; Kawamoto, Hirofumi; Okada, Hiroyuki; Yamamoto, Kazuhide

2015-07-01

The treatment of biliary stricture is crucially important for continuing stable chemotherapy for unresectable biliary carcinoma; however, there is no consensus regarding the use of hilar biliary drainage. In this study, we examined the efficacy of endoscopic over 3-branched biliary drainage using self-expandable metallic stents (SEMSs) in patients with unresectable malignant hilar biliary stricture (HBS). A total of 77 patients with unresectable HBS treated with a SEMS and chemotherapy were retrospectively reviewed. There were 59 patients with cholangiocarcinoma and 18 patients with gallbladder carcinoma. The patients were divided into 2 groups (4- or 3-branched group and 2- or 1-branched group) and compared with respect to the duration of stent patency and overall survival. A comparison of the patients' baseline characteristics showed no significant differences between the 4- or 3-branched group and the 2- or 1-branched group. Neither the duration of patency nor survival time exhibited significant differences between the 2 groups, although, among the patients achieving disease control , the duration of patency period and survival time of the 4- or 3-branched group were significantly higher than those observed in the 2- or 1-branched group (P=0.0231 and 0.0466). The use of endoscopic over 3-branched biliary drainage with a SEMS may improve the duration of patency in patients with HBS.

EW-7197 eluting nano-fiber covered self-expandable metallic stent to prevent granulation tissue formation in a canine urethral model.

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Kichang Han

Full Text Available To evaluate an EW-7197-eluting nanofiber-covered stent (NFCS for suppressing granulation tissue formation after stent placement in a canine urethral model.All experiments were approved by the committee of animal research. A total of 12 NFCSs were placed in the proximal and distal urethras of six dogs. Dogs were divided into two groups with 3 dogs each. The control stent (CS group received NFCSs and the drug stent (DS group received EW-7197 (1000 μg-eluting NFCSs. All dogs were sacrificed 8 weeks after stent placement Histologic findings of the stented urethra were compared using the Mann-Whitney U test.Stent placement was technically successful in all dogs without procedure-related complications. On urethrographic analysis, the mean luminal diameter was significantly larger in the DS group than in the CS group at 4 and 8 weeks after stent placement (all p 0.05.The EW-7197-eluting NFCS is effective and safe for suppressing granulation tissue formation after stent placement in a canine urethral model.

Tracheal obstruction caused by an expandable metallic stent: a case of successful removal of the stent.

Science.gov (United States)

Okuyama, Hiroomi; Kubota, Akio; Kawahara, Hisayoshi; Oue, Takaharu; Nose, Satoko; Ihara, Toshiyuki

2005-07-01

We report a case of tracheal obstruction caused by an expandable metallic stent. A 3-month-old girl with severe tracheomalacia had a placement of a Palmaz stent. At 3 years of age, she developed progressive dyspnea. The CT scan showed tracheal obstruction caused by granulation tissue over the stent. At operation, the stent was found to have penetrated the posterior tracheal wall. Under partial cardiopulmonary bypass, the stent was removed along with the membranous wall of the trachea, and the trachea was reconstructed using slide tracheoplasty. Tracheal obstruction is one of the serious complications caused by an expandable metallic stent. Direct open approach to the trachea under cardiopulmonary bypass is thought to be a safe way to manage this problem.

Fully covered self-expanding metal stents in the management of difficult common bile duct stones Prótesis metálicas autoexpandibles totalmente recubiertas en el tratamiento de coledocolitiasis difíciles

Directory of Open Access Journals (Sweden)

Jesús García-Cano

2013-01-01

Full Text Available Background and objectives: plastic biliary stents are often used after an ERCP session without complete common bile duct stones (CBDS extraction. Sometimes, the volume of biliary drainage with these stents may be insufficient. We present our experience with the use of fully covered self-expanding metal stents (FCSEMS in the setting of incomplete CBDS extraction. Patients and methods: after an ERCP session with difficult CBDS not completely removed, biliary FCSEMS (Wallflex were inserted in some patients when it was deemed that biliary sphincterotomy and a single plastic stent would not provide an adequate drainage. Results: a retrospective study was performed. Biliary FCSEMS were inserted in 29 patients, mean age 81 years. CBDS could not be extracted through a biliary sphincterotomy due to its large size (n = 18 or because of the presence of inflammatory distal strictures (n = 11. The greatest biliary drainage with shortest ERCP time was considered mandatory due to clinical instability of patients and/or poor tolerance to conscious sedation administered by the endoscopist. Successful biliary drainage was obtained in all cases. FCSEMS were removed after a median of 199.5 days in 16 patients with a complete CBDS extraction in 15 (93.7%. FCSEMS were not removed in the remaining 13 patients due to their clinical condition, and a wait-and-see strategy was undertaken. Conclusions: in selected cases, utilization of removable FCSEMS can be a good option for a quick and adequate biliary drainage in the setting of difficult CBDS. Because of the higher cost of these stents its use needs to be individualized.Introducción y objetivos: las prótesis biliares plásticas suelen emplearse tras una sesión de CPRE sin extracción completa de coledocolitiasis. En ocasiones, el calibre de drenaje con estas prótesis puede ser insuficiente. Presentamos nuestra experiencia en la utilización de prótesis metálicas autoexpandibles totalmente recubiertas (PMATR en

Self expandable polytetrafluoroethylene stent for carotid blowout syndrome.

Science.gov (United States)

Tatar, E C; Yildirim, U M; Dündar, Y; Ozdek, A; Işik, E; Korkmaz, H

2012-01-01

Carotid blowout syndrome (CBS) is an emergency complication in patients undergoing treatment for head and neck cancers. The classical management of CBS is the ligation of the common carotid artery, because suturing is not be possible due to infection and necrosis of the field. In this case report, we present a patient with CBS, in whom we applied a self-expandable polytetrafluoroethylene (PTFE) stent and observed no morbidity. Endovascular stent is a life-saving technique with minimum morbidity that preserves blood flow to the brain. We believe that this method is preferable to ligation of the artery in CBS.

Clinical benefits and oncologic equivalence of self-expandable metallic stent insertion for right-sided malignant colonic obstruction.

Science.gov (United States)

Ji, Woong Bae; Kwak, Jung Myun; Kang, Dong Woo; Kwak, Han Deok; Um, Jun Won; Lee, Sun-Il; Min, Byung-Wook; Sung, Nak Song; Kim, Jin; Kim, Seon Hahn

2017-01-01

The efficacy of stenting for right-sided malignant colonic obstruction is unknown. This study aimed to evaluate the safety, feasibility, and clinical benefits of self-expandable metallic stent insertion for right-sided malignant colonic obstruction. Clinical data from patients who underwent right hemicolectomy for right colon cancer from January 2006 to July 2014 at three Korea University hospitals were retrospectively reviewed. A total of 39 patients who developed malignant obstruction in the right-sided colon were identified, and their data were analyzed. Stent insertion was attempted in 16 patients, and initial technical success was achieved in 14 patients (87.5 %). No stent-related immediate complications were reported. Complete relief from obstruction was achieved in all 14 patients. Twenty-five patients, including two patients who failed stenting, underwent emergency surgery. In the stent group, 93 % (13/14) of patients underwent elective laparoscopic surgery, and only one surgery was converted to an open procedure. All patients in the emergency group underwent emergency surgery within 24 h of admission. In the emergency group, only 12 % (3/25) of patients underwent laparoscopic surgery, with one surgery converted to an open procedure. All patients in both groups underwent either laparoscopy-assisted or open right/extended right hemicolectomy with primary anastomoses as the first operation. The operative times, retrieved lymph nodes, and pathologic stage did not differ between the two groups. Postoperative hospital stay (9.4 ± 3.4 days in the stent group vs. 12.4 ± 5.9 in the emergency group, p = 0.089) and time to resume oral food intake (3.2 ± 2.1 days in the stent group vs. 5.7 ± 3.4 in the emergency group, p = 0.019) were shorter in the stent group. And there were no significant differences in disease-free survival and overall survival between the two groups. Stent insertion appears to be safe and feasible in patients with right

Transcatheter aortic value implantation with self-expandable nitinol valved stent: an experimental study in sheep

International Nuclear Information System (INIS)

Jiang Haibin; Huang Xinmiao; Bai Yuan

2011-01-01

Objective: to determine the feasibility and safety of transcatheter aortic valve implantation with domestic self-expandable nitinol valved stent in experimental sheep. Methods: A fresh pig pericardium was cross-linked with a 0.6% glutaraldehyde solution for 36 hours and then sutured on a nitinol self-expandable stent. Ten healthy sheep of (46.00±2.60) kg body weight were chosen for the study. Under general anesthesia, the device was delivered through catheter into the native aortic valve of the sheep via the femoral artery or abdominal aorta. The animals were followed up for three months. Results: Six devices were successfully delivered at the desired position in six sheep with no occurrence of complications. Angiographic and hemodynamic studies confirmed that the stents were fixed at correct position with competent valve function immediately and 90 days after the procedure. Technical failure or fatal complications occurred in the remaining four sheep. Conclusion: Implantation of a domestic nitinol self-expandable stent at the aortic valve position through a transcatheter approach is feasible in experimental sheep. (authors)

Deposition of metal Islands, metal clusters and metal containing single molecules on self-assembled monolayers

NARCIS (Netherlands)

Speets, Emiel Adrianus

2005-01-01

The central topic of this thesis is the deposition of metals on Self-Assembled Monolayers (SAMs). Metals are deposited in the form of submicron scale islands, nanometer scale clusters, and as supramolecular, organometallic coordination cages. Several SAMs on various substrates were prepared and

Repair of steam generator heating tubes by roll-expanded plugs: approach to cover multiple national regulations

Energy Technology Data Exchange (ETDEWEB)

Beck, J.; Ziegler, B.; Schoenheit, N. [AREVA NP Gmbh, Erlangen (Germany); Kostroun, F. [AREVA NP Canada Ltd., Pickering, ON (Canada)

2012-07-01

During operation, steam generators in nuclear power plants are subject to degradation mechanisms which have an impact on the component life-time. Most affected are the heating tubes which constitute the barrier of the contaminated primary cycle to the secondary side. Various corrosive attacks may cause wall thinning which requires tube repair. A common repair method is to plug the tubes by roll expanded plugs. This is a fast method, easily applicable and requires less equipment or personnel qualification as needed for weld plugs. After insertion, the plugs act as a pressure boundary from primary to secondary side. Although the function of the roll plug is simple, the different national regulations define the requirements which need to be fulfilled by a roll plug differently. In order to reduce the tooling as well as the plug types to a minimum, an approach according to one common design for different regulations and steam generator types is profitable. It was found, that the regulations according to the ASME Boiler and Pressure Vessel code in combination with the German Safety Standards of the German Nuclear Safety Standards Commission covers the regulations of the majority of utilities. To develop a roll plug which suits the different regulatory demands, efforts were made to consider all technical and regulatory boundary conditions implied on roll expanded plugs. This covering approach had an impact on the plug design, which was required to be Helium tight after installation and suitable for a 40 year component lifetime also in accident and emergency conditions. To prove the suitability of the plug design a comprehensive testing programme of the mechanical and chemical properties of the designed roll-expanded plug was launched. A summary of the plug design and testing as well as the main test results are described. (author)

Repair of steam generator heating tubes by roll-expanded plugs: approach to cover multiple national regulations

International Nuclear Information System (INIS)

Beck, J.; Ziegler, B.; Schoenheit, N.; Kostroun, F.

2012-01-01

During operation, steam generators in nuclear power plants are subject to degradation mechanisms which have an impact on the component life-time. Most affected are the heating tubes which constitute the barrier of the contaminated primary cycle to the secondary side. Various corrosive attacks may cause wall thinning which requires tube repair. A common repair method is to plug the tubes by roll expanded plugs. This is a fast method, easily applicable and requires less equipment or personnel qualification as needed for weld plugs. After insertion, the plugs act as a pressure boundary from primary to secondary side. Although the function of the roll plug is simple, the different national regulations define the requirements which need to be fulfilled by a roll plug differently. In order to reduce the tooling as well as the plug types to a minimum, an approach according to one common design for different regulations and steam generator types is profitable. It was found, that the regulations according to the ASME Boiler and Pressure Vessel code in combination with the German Safety Standards of the German Nuclear Safety Standards Commission covers the regulations of the majority of utilities. To develop a roll plug which suits the different regulatory demands, efforts were made to consider all technical and regulatory boundary conditions implied on roll expanded plugs. This covering approach had an impact on the plug design, which was required to be Helium tight after installation and suitable for a 40 year component lifetime also in accident and emergency conditions. To prove the suitability of the plug design a comprehensive testing programme of the mechanical and chemical properties of the designed roll-expanded plug was launched. A summary of the plug design and testing as well as the main test results are described. (author)

Use of nitinol self-expandable stents in 26 dogs with tracheal collapse.

Science.gov (United States)

Beranek, J; Jaresova, H; Rytz, U

2014-02-01

A study was designed to describe a novel approach to the treatment of tracheal collapse (TC) in dogs using self-expandable nitinol stents. Medical records were reviewed retrospectively for 26 client owned dogs in which nitinol stents were deployed. The entire length of trachea was supported independently of the extent of TC. Two overlapping stents were used instead of one in cases where one stent was not spanning the entire trachea adequately. The diameter of the cranial radiolucent portion of trachea, just behind the cricoid cartilage, was measured as a specific landmark to select the appropriate size of the stent. Two self-expandable nitinol stents were inserted in 9 of 26 dogs; the trachea in the rest of the cases was supported with only one stent. A follow up tracheoscopy was performed in 10 of 26 cases with recurrent clinical signs. Secondary tracheal stenosis in these cases was caused by stent fracture, granuloma or excessive stent shortening. Additional stents were placed successfully to expand the stenotic lumen. A support of the entire trachea may decrease risk of nitinol fracture at the end of the implant. Long term clinical improvement (25 of 26 dogs, 96 %) is comparable with the results of other studies.

Covered metal stent or multiple plastic stents for refractory pancreatic ductal strictures in chronic pancreatitis: a systematic review.

Science.gov (United States)

Shen, Yonghua; Liu, Mingdong; Chen, Min; Li, Yunhong; Lu, Ying; Zou, Xiaoping

2014-01-01

Refractory chronic pancreatitis has been proposed as a challenge for endoscopists following routine single plastic stenting. However, data on the efficacy and safety of further endoscopic stenting are still controversial. The current systematic review aimed to assess the efficacy and safety of placement of fully covered self-expandable metal stent (FCSEMS) and multiple plastic stents. Databases including MEDLINE, EMBASE, the Cochrane Library, CBM, CNKI, VIP, and WANFANG Database were used to search relevant trials. Published studies were assessed by using well-defined inclusion and exclusion criteria. The process was independently performed by two investigators. A total of 5 studies provided data of 80 patients. Forest plots and publication bias were not carried out because few studies were relevant and screened studies were all case series. The technical success rate was 100% both in placement of FCSEMS and multiple plastic stents. The functional success rate after placement of FCSEMS was 100%, followed by multiple plastic stents (94.7%). Complications occurred 26.2% after FCSEMS placement, which was not described in detail in multiple plastic stents. The stent migration rate was 8.2% for FCSEMS and 10.5% for multiple plastic stents. Reintervention rate was 9.8% for FCSEMS and 15.8% for multiple plastic stents. Pain improvement rate was 85.2% for FCSEMS and 84.2% for multiple plastic stents. FCSEMS appeared to be no significant difference with multiple plastic stents in treatment of refractory chronic pancreatitis. We need to develop more investigations. Copyright © 2014 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Mechanical Recanalization of Cerebral Artery Embolic Occlusion Using a Self-Expanding Stent: Experimental Analysis in Canine Model

International Nuclear Information System (INIS)

Choi, Jin Woo; Kim, Snag Joon; Lee, Deok Hee; Suh, Dae Chul

2011-01-01

To evaluate the feasibility of a self-expanding stent for acute embolic occlusion, and recanalization mechanism by histologic examination. Five mongrel dogs were used as study subjects. Each vertebral artery was occluded, and a self-expanding stent was used for recanalization. We evaluated the technical success rate for the placement of the stent to the targeted vessel, the recanalization rate, and residual stenosis. We obtained two specimens of the stented vertebral arteries for histologic evaluation. One dog died of an unknown cause during the induction of anesthesia. In two dogs, only one side of the vertebral artery was used, whereas both vertebral arteries were used in the remaining dogs. A total of six vertebral arteries were successfully occluded. The technical success rate for stenting without complication was 66.7%. The immediate recanalization rate after stenting was 100%. The residual stenosis was 35.6 ± 18.6%. On microscopic examination, the stent concentrically displaced the clot and the clot was captured between the stent mesh and arterial wall. Self-expanding stents were effective in revascularizing the cerebrovascular embolic occlusion. The self-expanding stent seemed to achieve recanalization by pushing the clot to the arterial wall and capturing the clot between the stent mesh and arterial wall.

Mechanical Recanalization of Cerebral Artery Embolic Occlusion Using a Self-Expanding Stent: Experimental Analysis in Canine Model

Energy Technology Data Exchange (ETDEWEB)

Choi, Jin Woo; Kim, Snag Joon; Lee, Deok Hee; Suh, Dae Chul [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, Ulsan University College of Medicine, Seoul (Korea, Republic of)

2011-07-15

To evaluate the feasibility of a self-expanding stent for acute embolic occlusion, and recanalization mechanism by histologic examination. Five mongrel dogs were used as study subjects. Each vertebral artery was occluded, and a self-expanding stent was used for recanalization. We evaluated the technical success rate for the placement of the stent to the targeted vessel, the recanalization rate, and residual stenosis. We obtained two specimens of the stented vertebral arteries for histologic evaluation. One dog died of an unknown cause during the induction of anesthesia. In two dogs, only one side of the vertebral artery was used, whereas both vertebral arteries were used in the remaining dogs. A total of six vertebral arteries were successfully occluded. The technical success rate for stenting without complication was 66.7%. The immediate recanalization rate after stenting was 100%. The residual stenosis was 35.6 {+-} 18.6%. On microscopic examination, the stent concentrically displaced the clot and the clot was captured between the stent mesh and arterial wall. Self-expanding stents were effective in revascularizing the cerebrovascular embolic occlusion. The self-expanding stent seemed to achieve recanalization by pushing the clot to the arterial wall and capturing the clot between the stent mesh and arterial wall.

Palliation of patients with esophagogastric neoplasms by insertion of a covered expandable modified Gianturco-Z endoprosthesis: experiences in 153 patients

NARCIS (Netherlands)

Bartelsman, J. F.; Bruno, M. J.; Jensema, A. J.; Haringsma, J.; Reeders, J. W.; Tytgat, G. N.

2000-01-01

We aimed to evaluate the short- and long-term outcomes of treatment by insertion of a covered expandable modified Gianturco-Z endoprosthesis (Song stent) in patients with esophagogastric malignancies. Consecutive patients with esophagogastric malignancies in whom a Song stent was inserted were

Temporary placement of covered retrievable expandable nitinol stents with barbs in high-risk surgical patients with benign prostatic hyperplasia: work in progress.

Science.gov (United States)

Kim, Choung-Soo; Song, Ho-Young; Jeong, In Gab; Yeo, Hyun Jin; Kim, Eun-Young; Park, Jung-Hoon; Yoon, Chang Jin; Paick, Sung Hyun; Park, Sang Woo; Bae, Jae-Ik; Won, Je Hwan

2011-10-01

To report the use of a newly constructed, covered, retrievable, expandable nitinol stent with barbs to overcome the problem of stent migration associated with conventional covered prostatic expandable stents and to evaluate prospectively the technical feasibility and clinical effectiveness of the stents in patients with benign prostatic hyperplasia (BPH). A covered retrievable expandable nitinol stent with four barbs was placed with use of an 18-F stent delivery system in seven consecutive patients with symptomatic BPH who had high operative risks. Age range of patients was 62-83 years (mean 74 years). In cases in which the stent migrated, it was replaced with a stent with eight barbs. The stents were routinely removed 4 months after placement using a 21-F stent removal set. Stent placement was technically successful and well tolerated in six of the seven patients. The remaining patient needed a second stent placement after removal of the first stent. The stent with four barbs migrated into the urinary bladder in four patients (57%); three of these patients received a second stent with eight barbs with good results, and the fourth patient did not need further treatment because his symptoms improved. Routine removal of the stent 4 months after placement was performed in three of the seven patients with good results. Retrievable stents with eight barbs seem to overcome the problem of stent migration associated with conventional prostatic expandable stents. Preliminary results suggest that stents with barbs are both feasible and effective in patients with BPH. Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.

Response of Balloon-Expandable Endoprosthetic Metallic Stents Subjected to Over-Expansion In Vitro

International Nuclear Information System (INIS)

Montague, B. J.; Kakimoto, W. M.; Arepally, A.; Razavi, M.; Dake, M. D.; Hofmann, L. V.

2004-01-01

We attempted to evaluate the in vitro behavior and performance of balloon-expandable endoprosthetic metallic stents subjected to over-expansion (OE). Seventy-two balloon-expandable endoprosthetic stents, representing 22 models from six manufacturers, were over- expanded in vitro. Stents were initially expanded to their maximum manufacturer- recommended diameter and then over-expanded incrementally to their endpoints. Endpoints for OE were either stent disarticulation or an inability to undergo further expansion despite balloon insufflation to maximum burst pressure. Measurements of stent dimensions were recorded at each overexpanded diameter and comparisons were made to manufacturer's specifications. A total of 288 balloon-driven expansions were performed on 72 stents. Sixteen stents were expanded to large diameters (≥ 16 mm), 20 stents underwent OE of 50% or greater. One model tended to disarticulate after OE greater than 50%. There were five models that had a tendency to disarticulate after minimal OE. Five models were resistant to OE (25% or less OE) but did not disarticulate. Nearly all stents showed some degree of foreshortening with OE, while 36 stents underwent foreshortening of 30% or more. Models that are not recommended for OE include Intrastent, Intrastent DoubleStrut, NIR Royale and Omniflex. Good candidates for OE include Intrastent DoubleStrut LD, Palmaz large, Medtronic Extra Support Biliary Plus and Medtronic Flexible Biliary. Palmaz XL remains the only model available for expansion from 20 to 28 mm in diameter. For the remaining stents, OE is possible, however, caution should be used

Hydrogen storage in Pd nanocrystals covered with a metal-organic framework

Science.gov (United States)

Li, Guangqin; Kobayashi, Hirokazu; Taylor, Jared M.; Ikeda, Ryuichi; Kubota, Yoshiki; Kato, Kenichi; Takata, Masaki; Yamamoto, Tomokazu; Toh, Shoichi; Matsumura, Syo; Kitagawa, Hiroshi

2014-08-01

Hydrogen is an essential component in many industrial processes. As a result of the recent increase in the development of shale gas, steam reforming of shale gas has received considerable attention as a major source of H2, and the more efficient use of hydrogen is strongly demanded. Palladium is well known as a hydrogen-storage metal and an effective catalyst for reactions related to hydrogen in a variety of industrial processes. Here, we present remarkably enhanced capacity and speed of hydrogen storage in Pd nanocrystals covered with the metal-organic framework (MOF) HKUST-1 (copper(II) 1,3,5-benzenetricarboxylate). The Pd nanocrystals covered with the MOF have twice the storage capacity of the bare Pd nanocrystals. The significantly enhanced hydrogen storage capacity was confirmed by hydrogen pressure-composition isotherms and solid-state deuterium nuclear magnetic resonance measurements. The speed of hydrogen absorption in the Pd nanocrystals is also enhanced by the MOF coating.

Results of the new nitinol self-expandable stents for distal biliary structures

NARCIS (Netherlands)

Smits, M.; Huibregtse, K.; Tytgat, G.

1995-01-01

The nitinol stent is a self-expandable spiral stent made of nickel-titanium alloy. We performed a pilot study to evaluate the method of stent insertion and stent efficacy. Twenty-eight patients with irresectable malignancy had nitinol stents inserted for obstructive jaundice due to distal biliary

Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

Science.gov (United States)

Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

2017-01-01

IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P stents was rejected. The mean number of ERCPs to achieve resolution

Self-expanding intracoronary stents in the treatment of coronary artery disease: new developments and future directions

NARCIS (Netherlands)

Lu, H.; Grundeken, M. J.; Koch, K. T.; Wykrzykowska, J. J.

2013-01-01

The first stent implanted in the human coronary circulation was a self-expandable (SE) stent and was introduced almost simultaneously with the first balloon-expandable (BE) stents in the late 1980s. Nowadays, the majority of the available stents are delivered by balloon expansion. While BE stents

Expanding Thurston maps

CERN Document Server

Bonk, Mario

2017-01-01

This monograph is devoted to the study of the dynamics of expanding Thurston maps under iteration. A Thurston map is a branched covering map on a two-dimensional topological sphere such that each critical point of the map has a finite orbit under iteration. It is called expanding if, roughly speaking, preimages of a fine open cover of the underlying sphere under iterates of the map become finer and finer as the order of the iterate increases. Every expanding Thurston map gives rise to a fractal space, called its visual sphere. Many dynamical properties of the map are encoded in the geometry of this visual sphere. For example, an expanding Thurston map is topologically conjugate to a rational map if and only if its visual sphere is quasisymmetrically equivalent to the Riemann sphere. This relation between dynamics and fractal geometry is the main focus for the investigations in this work.

Influence of K-ras status and anti-tumour treatments on complications due to colorectal self-expandable metallic stents: a retrospective multicentre study.

Science.gov (United States)

Fuccio, Lorenzo; Correale, Loredana; Arezzo, Alberto; Repici, Alessandro; Manes, Gianpiero; Trovato, Cristina; Mangiavillano, Benedetto; Manno, Mauro; Cortelezzi, Claudio Camillo; Dinelli, Marco; Cennamo, Vincenzo; de Bellis, Mario

2014-06-01

This study aimed to explore the relationship between K-ras status, anti-tumour treatments, and the complications of colorectal self-expandable metallic stenting in colorectal cancer. This is a retrospective, multicentre study of 91 patients with obstructive advanced colorectal cancer palliated with enteral stents between 2007 and 2011. K-ras wild-type tumours were diagnosed in 44 patients (48.4%); 82 (90.1%) received chemotherapy and 45 (49.4%) had additional biological therapy (34 bevacizumab, 11 cetuximab). Twenty-one (23.1%) experienced stent-related complications: 11 (52.4%) occurred in the K-ras mutant group (P=0.9). K-ras wild-type patients were not less likely to develop adverse events than K-ras mutant patients (OR, 0.99; 95% CI: 0.4-2.7). Overall mean time to complication was 167.6 days (range 4-720 days), with no difference between the two groups (141 vs. 197 days; P=0.5). Chemotherapy did not influence the risk of complications (OR, 0.56; 95% CI: 0.14-2.9), and there was no evidence that patients treated with chemotherapy and cetuximab were more likely to experience stent-related complications than patients treated with chemotherapy alone, or untreated (OR, 1.2; 95% CI: 0.2-5.9). Although perforation rates were higher with bevacizumab-based treatment (11.8% vs. 7%), this result was not statistically significant (P=0.69). K-ras mutation status, chemotherapy, and biological treatments should not influence colorectal stent-related complication rates. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

A novel lumen-apposing metal stent for endoscopic ultrasound-guided drainage of pancreatic fluid collections

DEFF Research Database (Denmark)

Walter, Daisy; Will, Uwe; Sanchez-Yague, Andres

2015-01-01

BACKGROUND AND STUDY AIMS: A novel large-diameter, lumen-apposing, self-expanding metal stent with bilateral flanges was recently developed for endoscopic ultrasound (EUS)-guided transmural drainage of symptomatic pancreatic fluid collections (PFCs). The aim of this study was to evaluate the effi......BACKGROUND AND STUDY AIMS: A novel large-diameter, lumen-apposing, self-expanding metal stent with bilateral flanges was recently developed for endoscopic ultrasound (EUS)-guided transmural drainage of symptomatic pancreatic fluid collections (PFCs). The aim of this study was to evaluate...

Management of empyema of gallbladder with percutaneous cholecysto-duodenal stenting in a case of hilar cholangiocarcinoma treated with common bile duct metallic stenting

Directory of Open Access Journals (Sweden)

Sheo Kumar

2011-01-01

Full Text Available Empyema of the gallbladder develops when the gallbladder neck is obstructed in the presence of infection, preventing pus from draining via the cystic duct. Treatment options include cholecystectomy or, in patients with comorbidities, drainage via percutaneous cholecystostomy, later followed by cholecystectomy. Here, we describe a 59-year-old man who presented with complaints of recurrent hiccups and was found to have cholangiocarcinoma causing obstruction to cystic duct drainage. The patient was managed successfully by percutaneous transhepatic cholecysto-duodenal self-expandable covered metal stent.

Metal availability and the expanding network of microbial metabolisms in the Archaean eon

Science.gov (United States)

Moore, Eli K.; Jelen, Benjamin I.; Giovannelli, Donato; Raanan, Hagai; Falkowski, Paul G.

2017-09-01

Life is based on energy gained by electron-transfer processes; these processes rely on oxidoreductase enzymes, which often contain transition metals in their structures. The availability of different metals and substrates has changed over the course of Earth's history as a result of secular changes in redox conditions, particularly global oxygenation. New metabolic pathways using different transition metals co-evolved alongside changing redox conditions. Sulfur reduction, sulfate reduction, methanogenesis and anoxygenic photosynthesis appeared between about 3.8 and 3.4 billion years ago. The oxidoreductases responsible for these metabolisms incorporated metals that were readily available in Archaean oceans, chiefly iron and iron-sulfur clusters. Oxygenic photosynthesis appeared between 3.2 and 2.5 billion years ago, as did methane oxidation, nitrogen fixation, nitrification and denitrification. These metabolisms rely on an expanded range of transition metals presumably made available by the build-up of molecular oxygen in soil crusts and marine microbial mats. The appropriation of copper in enzymes before the Great Oxidation Event is particularly important, as copper is key to nitrogen and methane cycling and was later incorporated into numerous aerobic metabolisms. We find that the diversity of metals used in oxidoreductases has increased through time, suggesting that surface redox potential and metal incorporation influenced the evolution of metabolism, biological electron transfer and microbial ecology.

New treatment of iliac artery disease: focus on the Absolute Pro® Vascular Self-Expanding Stent System

Directory of Open Access Journals (Sweden)

Gates L

2013-09-01

Full Text Available Lindsay Gates, Jeffrey Indes Vascular and Endovascular Surgery, Yale University School of Medicine, New Haven, CT, USA Abstract: Management of iliac artery disease has evolved over the years, from a surgical-only approach to a primarily endovascular-only approach as the first line treatment option. This has been continuously improved upon with the advent of new devices and applied technologies. Most recently in particular, the literature has shown good, reliable outcomes with the use of self-expandable stents in iliac artery atherosclerotic lesions. Nevertheless, no device is without its limitations, and the Absolute Pro® Vascular Self-Expanding Stent System was designed with the intent of overcoming some of the shortcomings of other available stents while maintaining acceptable postprocedural outcomes. Based on preliminary industry-acquired data, it has achieved these goals and appears to be an emergent competitor for the treatment of both focal and complex iliac artery lesions. Keywords: Absolute-Pro®, iliac stent, self-expanding stents, atherosclerotic disease

Treatment of intracranial atherosclerotic stenoses with balloon dilatation and self-expanding stent deployment (WingSpan)

Energy Technology Data Exchange (ETDEWEB)

Henkes, H. [Robert Janker Klinik, Bonn (Germany); Alfried Krupp Krankenhaus, Klinik fuer Radiologie und Neuroradiologie, Essen (Germany); Miloslavski, E.; Lowens, S.; Reinartz, J. [Robert Janker Klinik, Bonn (Germany); Liebig, T.; Kuehne, D. [Alfried Krupp Krankenhaus, Klinik fuer Radiologie und Neuroradiologie, Essen (Germany)

2005-03-01

The endovascular treatment of atherosclerotic intracranial arterial stenoses has previously been based on balloon dilatation or the deployment of a balloon expandable stent. Both methods have advantages (balloon: flexibility; balloon expandable stent: high radial force) and drawbacks (balloon: risk of elastic recoil and dissection; balloon expandable stent: limited flexibility, risk of injury to the vessel due to excessive straightening, overexpansion at ends of stent). A new combination of balloon dilatation, followed by the deployment of a self-expanding microstent has been applied in 15 patients with atherosclerotic arterial stenoses, symptomatic despite medical treatment. An anatomically and clinically adequate result was achieved in all patients. The initial degree of stenosis was 72% (mean). Balloon dilatation resulted in an average residual stenosis of 54% (mean), reduced further to a mean of 38% after stent deployment. Arterial dissection, occlusion of the target artery or symptomatic distal emboli was not encountered. In one patient, a side branch occlusion occurred after dilatation of a M1 stenosis, with complete neurological recovery. All patients were either stable or improved 4 weeks after the treatment. Recurrent TIA did not occur in any patient. Balloon dilatation and subsequent deployment of a self-expandable stent for the treatment of symptomatic intracranial arterial stenoses combines the advantages of both techniques and allows a rapid, clinically effective and technically safe treatment of these frequently challenging lesions. (orig.)

Treatment of intracranial atherosclerotic stenoses with balloon dilatation and self-expanding stent deployment (WingSpan)

International Nuclear Information System (INIS)

Henkes, H.; Miloslavski, E.; Lowens, S.; Reinartz, J.; Liebig, T.; Kuehne, D.

2005-01-01

The endovascular treatment of atherosclerotic intracranial arterial stenoses has previously been based on balloon dilatation or the deployment of a balloon expandable stent. Both methods have advantages (balloon: flexibility; balloon expandable stent: high radial force) and drawbacks (balloon: risk of elastic recoil and dissection; balloon expandable stent: limited flexibility, risk of injury to the vessel due to excessive straightening, overexpansion at ends of stent). A new combination of balloon dilatation, followed by the deployment of a self-expanding microstent has been applied in 15 patients with atherosclerotic arterial stenoses, symptomatic despite medical treatment. An anatomically and clinically adequate result was achieved in all patients. The initial degree of stenosis was 72% (mean). Balloon dilatation resulted in an average residual stenosis of 54% (mean), reduced further to a mean of 38% after stent deployment. Arterial dissection, occlusion of the target artery or symptomatic distal emboli was not encountered. In one patient, a side branch occlusion occurred after dilatation of a M1 stenosis, with complete neurological recovery. All patients were either stable or improved 4 weeks after the treatment. Recurrent TIA did not occur in any patient. Balloon dilatation and subsequent deployment of a self-expandable stent for the treatment of symptomatic intracranial arterial stenoses combines the advantages of both techniques and allows a rapid, clinically effective and technically safe treatment of these frequently challenging lesions. (orig.)

Self-expanding stent-assisted middle cerebral artery recanalization: technical note

International Nuclear Information System (INIS)

Sauvageau, Eric; Levy, Elad I.

2006-01-01

Investigation into pharmacological and mechanical means of improving recanalization rates by intraarterial therapy has led to technological development. Angiographic recanalization has been associated with improvement in clinical outcome. A clot retriever has recently joined an imperfect armamentarium for intraarterial stroke therapy. In this report, we describe successful recanalization of an acute thrombotic occlusion of the inferior division of the middle cerebral artery (MCA) achieved with a self-expanding stent. An 82-year-old woman with a history of coronary atherosclerosis and previous cerebellar hemorrhage presented with a National Institutes of Health Stroke Scale (NIHSS) score of 11. Perfusion computed tomography imaging showed a left MCA territory deficit. Diffusion-weighted magnetic resonance (MR) imaging revealed a small punctiform insular hyperintensity. Angiography documented occlusion of the inferior division of the left MCA (Thrombolysis in Myocardial Infarction or Thrombolysis in Cerebral Infarction, TIMI/TICI, grade 0). Intraarterial delivery of eptifibatide to the occlusion site failed to recanalize the vessel. Deployment of a self-expanding stent in the occluded segment resulted in complete revascularization of the distal vascular bed. Angiography performed on the next day confirmed patency of the stented vessel segment (TIMI/TICI 3). The patient was discharged 3 days after the procedure (NIHSS 3). MR angiography obtained 3 months after the procedure documented left MCA patency. This technique may have a role worthy of further investigation in acute stroke therapy. (orig.)

Synthesis of self-detached nanoporous titanium-based metal oxide

International Nuclear Information System (INIS)

Hu, F.; Wen, Y.; Chan, K.C.; Yue, T.M.; Zhou, Y.Z.; Zhu, S.L.; Yang, X.J.

2015-01-01

In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO 3 . The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO 2 (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm 2 , a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC

Synthesis of self-detached nanoporous titanium-based metal oxide

Energy Technology Data Exchange (ETDEWEB)

Hu, F. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Wen, Y. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Chan, K.C., E-mail: mfkcchan@inet.polyu.edu.hk [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Yue, T.M. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Zhou, Y.Z. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Zhu, S.L.; Yang, X.J. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

2015-09-15

In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO{sub 3}. The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO{sub 2} (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm{sup 2}, a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC.

Esophagojejunal Anastomosis Fistula, Distal Esophageal Stenosis, and Metalic Stent Migration after Total Gastrectomy

Directory of Open Access Journals (Sweden)

Nadim Al Hajjar

2015-01-01

Full Text Available Esophagojejunal anastomosis fistula is the main complication after a total gastrectomy. To avoid a complex procedure on friable inflamed perianastomotic tissues, a coated self-expandable stent is mounted at the site of the anastomotic leak. A complication of stenting procedure is that it might lead to distal esophageal stenosis. However, another frequently encountered complication of stenting is stent migration, which is treated nonsurgically. When the migrated stent creates life threatening complications, surgical removal is indicated. We present a case of a 67-year-old male patient who was treated at our facility for a gastric adenocarcinoma which developed, postoperatively, an esophagojejunostomy fistula, a distal esophageal stenosis, and a metallic coated self-expandable stent migration. To our knowledge, this is the first reported case of an esophagojejunostomy fistula combined with a distal esophageal stenosis as well as with a metallic coated self-expandable stent migration.

Self-Expanding Transcatheter Aortic Valve System for Symptomatic High-Risk Patients With Severe Aortic Stenosis

DEFF Research Database (Denmark)

Reichenspurner, Hermann; Schaefer, Andreas; Schäfer, Ulrich

2017-01-01

BACKGROUND: The CENTERA transcatheter heart valve (THV) is a low-profile, self-expanding nitinol valve made from bovine pericardial tissue that is 14-F compatible with a motorized delivery system allowing for repositionability. OBJECTIVES: The pivotal study evaluated safety and efficacy of this THV...... permanent pacemaker was implanted in 4.5% of patients receiving the THV (4.9% for patients at risk). CONCLUSIONS: The herein described THV is safe and effective at 30 days with low mortality, significant improvements in hemodynamic outcomes, and low incidence of adverse events. Of particular interest...... is the low incidence of permanent pacemaker implantations. (Safety and Performance Study of the Edwards CENTERA-EU Self-Expanding Transcatheter Heart Valve [CENTERA-2]; NCT02458560)....

A new approach to improve the local compressive properties of PPDO self-expandable stent.

Science.gov (United States)

Zhao, Fan; Xue, Wen; Wang, Fujun; Yu, Chenglong; Xu, Haiyan; Hao, Yi; Wang, Lu

2017-04-01

The radial performance of bioabsorbable polymeric intravascular stents is extremely important in assessing the efficiency of these devices in expanding narrow lumen, reducing stent recoil, and recovering to their original states after suffering from pulsating pressure. However, these stents remain inferior to metallic stents. Several thermal treatment conditions (60°C, 80°C, and 100°C for 1h) were investigated to improve the characteristics of poly(p-dioxanone) (PPDO) self-expandable stents. The local compressive force, stiffness, and viscoelasticity of these stents were also evaluated. Wide-angle X-ray diffraction and different scanning calorimetry measurements were performed to evaluate the recrystalline and thermodynamic changes of molecular chains. The declining conformer entropy of PPDO monofilaments was examined via energy analysis. The untreated stents had compressive modules of 514.80±70.59mN/mm, which was much higher than those of 80°C and 100°C treated stents (332.35±66.08mN/mm and 394.31±64.71mN/mm, respectively). Nevertheless, 100°C annealing stents had less stress relaxation and prior elastic recovery rate of 82.32±3.43mN and 92.55±1.61%, respectively, showing a much better shape stability than untreated stents (139.51±16.67mN and 86.18±3.57%, respectively). These findings present important clinical implications in the stent manufacturing process and warrant further study to develop new bioabsorbable stents with outstanding clinical efficacy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application of a novel retrievable self-expanding stent in intracranial aneurysm treatment

International Nuclear Information System (INIS)

Yang Zhigang; Liu Jianmin; Xu Yi; Huang Qinghai; Hong Bo; Zhao Wenyuan; Zhao Rui

2008-01-01

Objective: To assess the value of a novel retrievable self-expanding stent system (LEO) in intracranial aneurysm treatment. Methods: 43 patients with 44 intracranial aneurysms treated with LEO stent were retrospectively analized, including 16 aneurysms with single-stent deployment, 25 with stent-assisted technique, 2 with double-stent deployment and one with double-stent assisted coils. Follow up was carried out through imaging and clinical course. Results: The stent was easy for repositioning and all the stents were delivered successfully, except 1 stent with unsatisfactory position, 1 with acute in-stent thrombosis. During follow up, 1 case showed chronic in-stent thrombus and one with intimal hyperplasia. 22 aneurysms got compact coiled during procedure. Among 29 follow up cases, 72.4% aneurysms were cured or improved, 13.8% were stable and three dissection aneurysms enlarged within short period and two patients died. Conclusion: The new retrievable self-expanding stent (LEO), with the advantages of controlled delivery, easy deployment and choice for various types is a valuable system for vascular reconstruction of intracranial aneurysm with thrombosis. (authors)

Expander for Thin-Wall Tubing

Science.gov (United States)

Pessin, R.

1983-01-01

Tool locally expands small-diameter tubes. Tube expander locally expands and deforms tube: Compressive lateral stress induced in elastomeric sleeve by squeezing axially between two metal tool parts. Adaptable to situations in which tube must have small bulge for mechanical support or flow control.

Clinical remission following endoscopic placement of retrievable, fully covered metal stents in patients with esophageal achalasia.

Science.gov (United States)

Zeng, Y; Dai, Y-M; Wan, X-J

2014-01-01

Metal stents may represent an alternative therapy in the treatment of achalasia. We therefore evaluated the effectiveness of retrievable, fully covered metal stents in patients with achalasia. Fifty-nine patients with achalasia were treated with retrievable, fully covered metal stents. Symptoms using a global symptom score (0-10), lower esophageal sphincter (LES) resting pressure, LES relaxation, and simultaneous contraction of the esophagus were analyzed before and 1 week and 1 month after intervention. Complications and treatment outcomes were followed up at 6, 12, 18, and 24 months postoperatively. Stent placement was successful, and clinical symptoms resolved (P treatment in patients with achalasia. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Flame Speed and Self-Similar Propagation of Expanding Turbulent Premixed Flames

Science.gov (United States)

Chaudhuri, Swetaprovo; Wu, Fujia; Zhu, Delin; Law, Chung K.

2012-01-01

In this Letter we present turbulent flame speeds and their scaling from experimental measurements on constant-pressure, unity Lewis number expanding turbulent flames, propagating in nearly homogeneous isotropic turbulence in a dual-chamber, fan-stirred vessel. It is found that the normalized turbulent flame speed as a function of the average radius scales as a turbulent Reynolds number to the one-half power, where the average radius is the length scale and the thermal diffusivity is the transport property, thus showing self-similar propagation. Utilizing this dependence it is found that the turbulent flame speeds from the present expanding flames and those from the Bunsen geometry in the literature can be unified by a turbulent Reynolds number based on flame length scales using recent theoretical results obtained by spectral closure of the transformed G equation.

Comparison of Laparoscopic versus Open Surgery after Insertion of Self-Expandable Metallic Stents in Acute Malignant Colorectal Obstruction: A Case-Matched Study

Directory of Open Access Journals (Sweden)

Chotirot Angkurawaranon

2017-03-01

Full Text Available Background: Self-expanding metallic stents (SEMS have been acknowledged in management of acute colorectal obstruction. The surgical approach after SEMS insertion varies from open approach to laparoscopic-assisted approach. The primary objective of this study was to compare the outcomes of laparoscopic approach and open approach after SEMS insertion. Methods: From January 2007 to December 2010, cross-sectional medical records reviewed a total of 76 patients who underwent colorectal stenting with SEMS. Patients and tumor characteristics, complications, morbidity and mortality were obtained. Results: Forty-three patients underwent SEMS placement as a bridge to surgery. Laparoscopic-assisted surgery (LS was performed in 24 patients (55.8%, and open surgery (OS was performed in 19 patients (44.2%. All clinicopathological parameters were matched. The technical success of SEMS was found in 42 patients (97.7%, and the clinical stent success was 100%. LS had a higher chance of primary anastomosis than OS (p=0.012; Odd ratio 2.717; 95%CI: 1.79-4.012. LS had a lower permanent ostomy rate (p=0.031; Odd ratio 0.385; 95%CI: 0.259-0.572 and lower estimated blood loss (p=0.024; Odd ratio 0.23; 95%CI: 0.006-0.086. The post-operative complications, mortality rate, recurrence rate, disease free status, and overall survival rates between the two groups were non-significant. Conclusion: Colonic stent is an effective treatment of acute malignant colonic obstruction. The authors suggest the advantage of laparoscopic approach resection after colonic stenting results in a higher primary anastomosis rate, and lower blood loss than open surgery.

Self-assembled monolayers on metal oxides : applications in nanotechnology

NARCIS (Netherlands)

Yildirim, O.

2010-01-01

The thesis describes the use of phosph(on)ate-based self-assembled monolayers (SAMs) to modify and pattern metal oxides. Metal oxides have interesting electronic and magnetic properties such as insulating, semiconducting, metallic, ferromagnetic etc. and SAMs can tailor the surface properties. FePt

Biodegradable shape-memory block co-polymers for fast self-expandable stents.

Science.gov (United States)

Xue, Liang; Dai, Shiyao; Li, Zhi

2010-11-01

Block co-polymers PCTBVs (M(n) of 36,300-65,300 g/mol, T(m) of 39-40 and 142 degrees C) containing hyperbranched three-arm poly(epsilon-caprolactone) (PCL) as switching segment and microbial polyester PHBV as crystallizable hard segment were designed as biodegradable shape-memory polymer (SMP) for fast self-expandable stent and synthesized in 96% yield by the reaction of three-arm PCL-triol (M(n) of 4200 g/mol, T(m) of 47 degrees C) with methylene diphenyl 4,4'-diisocyanate isocynate (MDI) to form the hyperbrached MDI-linked PCL (PTCM; M(n) of 25,400 g/mol and a T(m) of 38 degrees C), followed by further polymerization with PHBV-diol (M(n) of 2200 g/mol, T(m) of 137 and 148 degrees C). The polymers were characterized by (1)H NMR, GPC, DSC, tensile test, and cyclic thermomechanical tensile test. PCTBVs showed desired thermal properties, mechanical properties, and ductile nature. PCTBV containing 25 wt% PHBV (PCTBV-25) demonstrated excellent shape-memory property at 40 degrees C, with R(f) of 94%, R(r) of 98%, and shape recovery within 25s. PCTBV-25 was also shown as a safe material with good biocompatibility by cytotoxicity tests and cell growth experiments. The stent made from PCTBV-25 film showed nearly complete self-expansion at 37 degrees C within only 25 s, which is much better and faster than the best known self-expandable stents. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Outcome of self-expandable metallic stent deployment in patients with malignant gastroduodenal outlet obstruction and Niti-S and WallFlex comparison: a multicenter retrospective clinical study.

Science.gov (United States)

Kato, Hironari; Kawamoto, Hirofumi; Matsumoto, Kazuya; Moriyama, Ichiro; Kamada, Hideki; Tsutsumi, Koichiro; Goto, Daisuke; Fukuba, Nobuhiko; Kato, Kiyohito; Sonoyama, Hiroki; Isomoto, Hajime; Okada, Hiroyuki

2016-08-01

Several studies report on the outcomes of self-expandable metallic stents (SEMSs) deployment for malignant gastric outlet obstruction (GOO). However, data was mostly based on the analysis of single-center studies including only a small number of patients. This study aimed to evaluate clinical outcomes after the deployment of SEMS in patients with malignant GOO and to compare the clinical outcomes of two metallic stents with different designs. Altogether 125 consecutive patients from five institutions were included. Clinical outcomes were evaluated according to technical success, clinical success, stent patency period, survival period and complications. A comparison of clinical outcomes between Niti-S pyloric/duodenal and WallFlex duodenal stents was also undertaken. Rates for clinical and technical success were 100% and 92.0%, respectively. The median stent patency and survival periods were 72.0 days (range 3-775 days) and 75.0 days (range 3-775 days), respectively. The rate of overall adverse events was 28.8%. The rate of stent dysfunction was 16.8%, and that of adverse events, except stent dysfunction was 12.0%. Massive bleeding occurred in two patients as a late complication. The clinical success rate for Niti-S stent was significantly higher than that for WallFlex stent (96.2% vs 84.8%, P = 0.023). We successfully deployed a SEMS in malignant GOO. The selection of a SEMS with a lower axial force may be important for patients to resume the oral food intake. Additionally, consideration must be given to the appropriate management of fatal bleeding as a late complication. © 2016 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Reduction of front-metallization grid shading in concentrator cells through laser micro-grooved cover glass

International Nuclear Information System (INIS)

García-Linares, Pablo; Voarino, Philippe; Besson, Pierre; Baudrit, Mathieu; Dominguez, César; Dellea, Olivier; Fugier, Pascal

2015-01-01

Concentrator solar cell front-grid metallizations are designed so that the trade-off between series resistance and shading factor (SF) is optimized for a particular irradiance. High concentrator photovoltaics (CPV) typically requires a metallic electrode pattern that covers up to 10% of the cell surface. The shading effect produced by this front electrode results in a significant reduction in short-circuit current (I SC ) and hence, in a significant efficiency loss. In this work we present a cover glass (originally meant to protect the cell surface) that is laser-grooved with a micrometric pattern that redirects the incident solar light towards interfinger regions and away from the metallic electrodes, where they would be wasted in terms of photovoltaic generation. Quantum efficiency (QE) and current (I)-voltage (V) characterization under concentration validate the proof-of-concept, showing great potential for CPV applications

Reduction of front-metallization grid shading in concentrator cells through laser micro-grooved cover glass

Energy Technology Data Exchange (ETDEWEB)

García-Linares, Pablo, E-mail: pablo.garcia-linares@cea.fr; Voarino, Philippe; Besson, Pierre; Baudrit, Mathieu [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Dominguez, César [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Instituto de Energía Solar - Universidad Politécnica de Madrid, Madrid (Spain); Dellea, Olivier; Fugier, Pascal [CEA-LITEN, Laboratoire de Surfaces Nanostructurées, Grenoble (France)

2015-09-28

Concentrator solar cell front-grid metallizations are designed so that the trade-off between series resistance and shading factor (SF) is optimized for a particular irradiance. High concentrator photovoltaics (CPV) typically requires a metallic electrode pattern that covers up to 10% of the cell surface. The shading effect produced by this front electrode results in a significant reduction in short-circuit current (I{sub SC}) and hence, in a significant efficiency loss. In this work we present a cover glass (originally meant to protect the cell surface) that is laser-grooved with a micrometric pattern that redirects the incident solar light towards interfinger regions and away from the metallic electrodes, where they would be wasted in terms of photovoltaic generation. Quantum efficiency (QE) and current (I)-voltage (V) characterization under concentration validate the proof-of-concept, showing great potential for CPV applications.

Surface sealing using self-assembled monolayers and its effect on metal diffusion in porous low-k dielectrics studied using monoenergetic positron beams

International Nuclear Information System (INIS)

Uedono, Akira; Armini, Silvia; Zhang, Yu; Kakizaki, Takeaki; Krause-Rehberg, Reinhard; Anwand, Wolfgang; Wagner, Andreas

2016-01-01

Graphical abstract: - Highlights: • Pores with cubic pore side lengths of 1.1 and 3.1 nm coexisted in the low-k film. • For the sample without the SAM sealing process, metal atoms diffused from the top Cu/MnN layer into the OSG film and were trapped by the pores. Almost all pore interiors were covered by those metals. • For the sample damaged by a plasma etch treatment before the SAM sealing process, self-assembled molecules diffused into the OSG film, and they were preferentially trapped by larger pores. - Abstract: Surface sealing effects on the diffusion of metal atoms in porous organosilicate glass (OSG) films were studied by monoenergetic positron beams. For a Cu(5 nm)/MnN(3 nm)/OSG(130 nm) sample fabricated with pore stuffing, C_4F_8 plasma etch, unstuffing, and a self-assembled monolayer (SAM) sealing process, it was found that pores with cubic pore side lengths of 1.1 and 3.1 nm coexisted in the OSG film. For the sample without the SAM sealing process, metal (Cu and Mn) atoms diffused from the top Cu/MnN layer into the OSG film and were trapped by the pores. As a result, almost all pore interiors were covered with those metals. For the sample damaged by an Ar/C_4F_8 plasma etch treatment before the SAM sealing process, SAMs diffused into the OSG film, and they were preferentially trapped by larger pores. The cubic pore side length in these pores containing self-assembled molecules was estimated to be 0.7 nm. Through this work, we have demonstrated that monoenergetic positron beams are a powerful tool for characterizing capped porous films and the trapping of atoms and molecules by pores.

Removal of retrievable self-expandable urethral stents: experience in 58 stents

International Nuclear Information System (INIS)

Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo; Park, Hyungkeun

2006-01-01

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8±42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

Removal of retrievable self-expandable urethral stents: experience in 58 stents

Energy Technology Data Exchange (ETDEWEB)

Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul (Korea); Park, Hyungkeun [Asan Medical Center, Department of Urology, University of Ulsan College of Medicine, Seoul (Korea)

2006-09-15

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8{+-}42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

Hydrogen embrittlement of metals. A bibliography with abstracts. Search period covered: 1964--August 1975

International Nuclear Information System (INIS)

Smith, M.F.

1975-10-01

The research covers the hydrogen embrittlement of both ferrous and nonferrous metals and alloys and includes nuclear technology, aircraft metallurgy, mechanical properties, testing, electroplating, fatigue, corrosion and fracture. Contains 230 abstracts

Metal selective co-ordinative self-assembly of π-donors

Indian Academy of Sciences (India)

Metal selective co-ordinative nanostructures were constructed by the supramolecular ... observed an anomalous binding of metal ion to the core sulphur groups causing redox changes in the TTF ... attention on metal-assisted co-ordinative self-assembly ..... M TTF-Py in 1:1 CHCl3: MeCN and (c) photographs showing visual.

Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

International Nuclear Information System (INIS)

Fanelli, Fabrizio; Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

2011-01-01

We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound–color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

Flexible Aperture Tuning Solution for Cellular Main Antenna in Metallic Back Cover Mobile Phone

Directory of Open Access Journals (Sweden)

Yew Choon Mark Tan

2017-10-01

Full Text Available Metal housing has been used extensively on portable communication devices such as on mobile phones and tablets. The choice of metal housing ranges from metallic rim to metallic back cover. This metal housing tends to improve the outlook appearance of the mobile devices, and add mechanical strength towards the mobile devices. However, from the aspect of the communication antenna, the metal housing often posts great challenges towards the flexibility in antenna design and reduction in antenna performance. This paper presents an approach to overcome the challenges by integrating the metal housing of the mobile phone as part of the antenna, along with the introduction of tunable antenna concept to provide different forms of Aperture Tuning to the Cellular Main Antenna, to satisfy its wide frequency band coverages for the 2nd, 3rd and 4th Generation (2G, 3G and 4G mobile network.

Radiotherapy of malignant oesophageal stenosis by insertion of an expansible metal stent

International Nuclear Information System (INIS)

Slampa, P.; Spurny, V.; Valek, V.; Benda, K.; Vomela, J.; Kala, Z.

1998-01-01

Dysphagia is a frequent and the most common symptom of malignant disease in the oesophagus. Adequate palliation with low morbidity in dysphagia due to inoperable oesophageal carcinoma is difficult to achieve. Surgery probably provides the most effective palliation of dysphagia, but it is associated with a high morbidity. Self-expanding metal stents seem to offer excellent palliation with minimal morbidity for patients with inoperable carcinoma of the oesophagus. Stent treatment has a good and prompt effect on dysphagia and can be recommended for palliation of patients with malignant oesophageal strictures. A combination of radiotherapy (40 Gy) and the self-expanding metal stents can result in a prolonged palliation. This combined treatment was generally well tolerated

Self-Expandable Stenting over a Stent Graft for the Exclusion of a Carotid Stump: Troubleshooting for Device Incompatibility

International Nuclear Information System (INIS)

Youn, Sung Won; Kim, Ho Kyun; Do, Jin Kook; Kim, Young Whan

2011-01-01

Carotid stump, the blind remnant of an occluded internal carotid artery, can be a potential source of microemboli, and warrants its exclusion from the vascular lumen to prevent the recurrence of a microembolism. In a 69-year-old male with a symptomatic carotid stump and acute angle between left common carotid artery and aortic arch, a 7-Fr. shuttle sheath was scarcely placed into the left carotid artery but the 7-mm-diameter stent-graft-loading balloon could not be inserted into the 7-Fr. shuttle sheath. With the mounting a stent graft over a 5-mm balloon, the balloon-expandable stent graft was unfolded. The self-expandable stent was placed over the stent graft, and an 8-mm balloon was subsequently expanded. Self-expanding stenting can be useful for troubleshooting in a case of device incompatibility coming from the different calibers of the external and common carotid arteries for the successful exclusion of a symptomatic carotid stump.

Self-Expandable Stenting over a Stent Graft for the Exclusion of a Carotid Stump: Troubleshooting for Device Incompatibility

Energy Technology Data Exchange (ETDEWEB)

Youn, Sung Won; Kim, Ho Kyun [Dept. of Radiology, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of); Do, Jin Kook [Dept. of Neurology, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of); Kim, Young Whan [Dept. of Radiology, University College of Medicine, Daegu (Korea, Republic of)

2011-12-15

Carotid stump, the blind remnant of an occluded internal carotid artery, can be a potential source of microemboli, and warrants its exclusion from the vascular lumen to prevent the recurrence of a microembolism. In a 69-year-old male with a symptomatic carotid stump and acute angle between left common carotid artery and aortic arch, a 7-Fr. shuttle sheath was scarcely placed into the left carotid artery but the 7-mm-diameter stent-graft-loading balloon could not be inserted into the 7-Fr. shuttle sheath. With the mounting a stent graft over a 5-mm balloon, the balloon-expandable stent graft was unfolded. The self-expandable stent was placed over the stent graft, and an 8-mm balloon was subsequently expanded. Self-expanding stenting can be useful for troubleshooting in a case of device incompatibility coming from the different calibers of the external and common carotid arteries for the successful exclusion of a symptomatic carotid stump.

Preparation and characterization of expanded graphite/metal oxides for antimicrobial application.

Science.gov (United States)

Hung, Wei-Che; Wu, Kuo-Hui; Lyu, Dong-Yi; Cheng, Ken-Fa; Huang, Wen-Chien

2017-06-01

Composite materials based on expanded graphite (EG) and metal oxide (MO) particles was prepared by an explosive combustion and blending method. The objective of the study was to develop EG impregnated with metal oxide particulates (Ag 2 O, CuO and ZnO) and evaluate the level of protection the materials conferred against biological agents. The physical properties of the EG/MO composites were examined using SEM, EDX and XRD spectroscopy, and the results indicated that the MO particles were incorporated into the EG matrix after impregnation. The antimicrobial activities of the EG/MO composites against Gram-positive bacteria, Gram-negative bacteria and Bacillus anthracis were investigated using zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and plate-counting methods. EG/Ag 2 O exhibited a stronger antibacterial activity than EG/CuO and EG/ZnO, with a MIC of 0.3mg/mL and a MBC of 0.5mg/mL. To the best of our knowledge, few studies have demonstrated that EG/MO composites can inhibit the growth of Bacillus anthracis-adhered cells, thus preventing the process of biofilm formation. Nanoscale metal oxides display enhanced reactive properties toward bacteria due to their high surface area, large number of highly reactive edges, corner defect sites and high surface to volume ratio. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of visibility for four self-expanding nitinol bare stents in vitro

International Nuclear Information System (INIS)

Wiesinger, Benjamin; Stutz, Alexander; Schmehl, Joerg; Groezinger, Gerd; Claussen, Claus Detlef; Wiskirchen, Jakub

2012-01-01

Background Sufficient radiopacity of stents is a prerequisite for safe interventions and minimization of the radiation dose for the patient and the interventionist. Modern nitinol stents are considered less radiopaque compared to formerly used stents. Purpose To evaluate the objective detection rate (ODR) and the subjective radiopacity score (SRS) of four self-expanding nitinol stents with their markers on a phantom human pelvis. Material and Methods We evaluated the ODR (as a percentage of correctly identified stents) and the SRS (on a scale from 0 = not visible to 4 = excellent visibility) for four self-expanding nitinol stents (SinusSuperflex, SMART, Luminexx, Zilver) with 8 mm diameter and 40 mm length. Stents were placed on a phantom human pelvis and images of the stents were taken in four different positions (right and left lumbosacral joint and near the right and left limbus acetabuli) using the following modes: spotfilm, pulsed fluoroscopy (4, 7.5, 15, and 30 pulses/min) and at three different digital magnification modes. Dose area products (DAPs) were assessed. Results ODR and SRS, respectively, were significantly increased for the SMART stent compared to all other tested stents (P < 0.05): SMART 93.53% and 2.43, SinusSuperflex 90.81% and 2.21, Luminexx 90.39% and 2.20, and Zilver 89.28% and 2.21. ODR was significantly reduced in position 3 where the bone overlap was more pronounced for all stents (detection rates 77.14-79.56%). An increase in magnification significantly improved the ODR and SRS for all stents (70.33-99.25% and 1.07-3.28, respectively, P < 0.05). Increased pulsing frequency did not improve the ODR of the various stents but did increase the DAP. Conclusion The SMART stent had the best overall performance. In the presence of bone overlap, all self-expanding nitinol stents had poor results. Increased pulsing frequency did not improve ODR or SRS but did increase the DAP. Use of digital magnification modes had no effect on DAP increasing ODR

Self-stabilizing Synchronization in Mobile Sensor Networks with Covering

Science.gov (United States)

Beauquier, Joffroy; Burman, Janna

Synchronization is widely considered as an important service in distributed systems which may simplify protocol design. Phase clock is a general synchronization tool that provides a form of a logical time. This paper presents a self-stabilizing (a tolerating state-corrupting transient faults) phase clock algorithm suited to the model of population protocols with covering. This model has been proposed recently for sensor networks with a very large, possibly unknown number of anonymous mobile agents having small memory. Agents interact in pairs in an asynchronous way subject to the constraints expressed in terms of the cover times of agents. The cover time expresses the "frequency" of an agent to communicate with all the others and abstracts agent's communication characteristics (e.g. moving speed/patterns, transmitting/receiving capabilities). We show that a phase clock is impossible in the model with only constant-state agents. Hence, we assume an existence of resource-unlimited agent - the base station.

Long-term safety and outcome of a temporary self-expanding metallic stent for achalasia: a prospective study with a 13-year single-center experience

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jun-Gong; Li, Yong-Dong; Li, Ming-Hua; Shang, Ke-Zhong [Shanghai Tong Ji University, Department of Radiology, Tenth Affiliated People' s Hospital, Shanghai (China); Cheng, Ying-Sheng [Shanghai Tong Ji University, Department of Radiology, Tenth Affiliated People' s Hospital, Shanghai (China); Shanghai Jiao Tong University, Department of Radiology, Sixth Affiliated People' s Hospital, Shanghai (China); Chen, Ni-Wei; Chen, Wei-Xiong [Shanghai Jiao Tong University, Department of Gastroenterology, Sixth Affiliated People' s Hospital, Shanghai (China)

2009-08-15

To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4-5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n=4, 5.33%), chest pain (n=28, 38.7%), reflux (n=15, 20%), and bleeding (n=9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1-3, 3-5, 5-8, 8-10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 {+-} 0.28 years (95% CI: 2.25-3.35) and 4.28 {+-} 0.40 years (95% CI: 3.51-5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate. (orig.)

Palliation of gastrointestinal obstruction with expandable metallic stents: 3 case reports

International Nuclear Information System (INIS)

Langhorne, N.B.; Asch, M.R.; Jaffer, N.

1997-01-01

Interventional radiologists are often asked to assist in the care of patients with advanced malignant disease. Frequent clinical problems include dysphagia due to proximal involvement of the gastrointestinal (GI) tract or bowel obstruction as a result of more distal compression. Although a number of endoscopic and surgical options are available, the placement of expandable metallic stents in the bowel lumen has recently been reported as efficacious, safe and cost-effective. We present our experience with placement of stents in the small and large bowel, describing the clinical scenarios, the reasons for stent placement, and the technique and results in each of 3 cases and comparing our experience with those of others, as reported in the literature. (author)

Endovascular treatment of intrahepatic inferior vena cava obstruction from malignant hepatocellular tumor thrombus utilizing Luminexx self-expanding nitinol stents

International Nuclear Information System (INIS)

Stambo, Glenn W.; Leto, John; George, Christopher; Van Epps, Kelly; Woeste, Troy; Berlet, Mathew

2008-01-01

Inferior vena cava (IVC) obstruction is a well-described clinical entity. Most IVC obstructions from malignant neoplasms are a direct result of tumor compression [Oviedo J, Cerda S. Vascular invasion by hepatocellular carcinoma. Arch Pathol Lab Med 2001;125: 454-5; Furui S, Sawada S, et al. Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome. Radiology 1995;195:147-52; Fletcher WS, Lakin PC, et al. Results of treatment of inferior vena cava syndrome with expandable metallic stents. Arch Surg 1998;133:935-8]. The symptoms of IVC obstruction include progressive ascites, scrotal edema and lower body edema. These constellations of symptoms are described as IVC syndrome and are devastating to a patient with end-stage cancer. We describe a palliative therapy utilizing Luminexx nitinol self-expanding stents to treat intracaval hepatoma thrombus obstructing the IVC. The procedure is rapidly performed, technically reliable, and has essentially no morbidity or mortality. This procedure can be performed in the interventional radiology suite with excellent results resolving the IVC syndrome soon after placement of the stents. We believe endovascular stenting as an excellent palliative therapy for patients with IVC syndrome and should be the treatment of choice for caval obstructions due to intraluminal tumor thrombus

Endovascular treatment of intrahepatic inferior vena cava obstruction from malignant hepatocellular tumor thrombus utilizing Luminexx self-expanding nitinol stents

Energy Technology Data Exchange (ETDEWEB)

Stambo, Glenn W. [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 4516 North Armenia Avenue, Tampa, FL 33603 (United States)], E-mail: xraydoc2@yahoo.com; Leto, John [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 3001 W. Dr. Martin Luther King Jr. Blvd., Tampa, FL 33607 (United States); George, Christopher [Department of Hematology and Oncology, St. Joseph' s Hospital and Medical Center, 4301 W. Habana Avenue, Suite 1, Tampa, FL 33607 (United States); Van Epps, Kelly; Woeste, Troy; Berlet, Mathew [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 4516 North Armenia Avenue, Tampa, FL 33603 (United States)

2008-05-15

Inferior vena cava (IVC) obstruction is a well-described clinical entity. Most IVC obstructions from malignant neoplasms are a direct result of tumor compression [Oviedo J, Cerda S. Vascular invasion by hepatocellular carcinoma. Arch Pathol Lab Med 2001;125: 454-5; Furui S, Sawada S, et al. Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome. Radiology 1995;195:147-52; Fletcher WS, Lakin PC, et al. Results of treatment of inferior vena cava syndrome with expandable metallic stents. Arch Surg 1998;133:935-8]. The symptoms of IVC obstruction include progressive ascites, scrotal edema and lower body edema. These constellations of symptoms are described as IVC syndrome and are devastating to a patient with end-stage cancer. We describe a palliative therapy utilizing Luminexx nitinol self-expanding stents to treat intracaval hepatoma thrombus obstructing the IVC. The procedure is rapidly performed, technically reliable, and has essentially no morbidity or mortality. This procedure can be performed in the interventional radiology suite with excellent results resolving the IVC syndrome soon after placement of the stents. We believe endovascular stenting as an excellent palliative therapy for patients with IVC syndrome and should be the treatment of choice for caval obstructions due to intraluminal tumor thrombus.

Expanding beyond canonical metabolism: Interfacing alternative elements, synthetic biology, and metabolic engineering

Directory of Open Access Journals (Sweden)

Kevin B. Reed

2018-03-01

Full Text Available Metabolic engineering offers an exquisite capacity to produce new molecules in a renewable manner. However, most industrial applications have focused on only a small subset of elements from the periodic table, centered around carbon biochemistry. This review aims to illustrate the expanse of chemical elements that can currently (and potentially be integrated into useful products using cellular systems. Specifically, we describe recent advances in expanding the cellular scope to include the halogens, selenium and the metalloids, and a variety of metal incorporations. These examples range from small molecules, heteroatom-linked uncommon elements, and natural products to biomining and nanotechnology applications. Collectively, this review covers the promise of an expanded range of elemental incorporations and the future impacts it may have on biotechnology.

Self-expanding metal stents versus antrectomy for the palliative treatment of obstructive adenocarcinoma of the gastric antrum Prótesis metálicas autoexpandibles versus antrectomía en el tratamiento paliativo del adenocarcinoma obstructivo del antro gástrico

Directory of Open Access Journals (Sweden)

Juan Octavio Alonso-Larraga

2012-04-01

Full Text Available Background: gastric cancer patients are first diagnosed with an unresectable tumor in up to 40% of cases. Gastric outlet obstruction causes nausea, vomiting, dehydration and malnutrition. The aim of the study was to compare self-expanding metal stents to antrectomy and Roux-en Y gastrojejunostomy for palliation of obstructive adenocarcinoma of the gastric antrum. Methods: retrospective study in patients with obstructing cancer of the gastric antrum. Patients were divided into two groups: group A, underwent endoscopic placement of self-expanding metal stents and group B underwent surgical treatment with antrectomy and Roux-en Y gastrojejunostomy. Collected Data included: age, gender, performance status (Karnofsky's score, body mass index, histopathology, clinical stage (TNM classification, technical and clinical success of the procedure, time to oral intake, in-hospital stay, re-intervention rate, and complications related to the treatment and survival. Results: a total of 39 patients with gastric adenocarcinoma were included, 21 male and 18 female. Nineteen patients were assigned to group A and 20 patients to group B. There were no statistically significant differences between groups in regards to age, body mass index, Karnofsky's score and clinical stage. The technical and clinical success was similar for both groups. There was a statistically significant difference between groups favoring Self-expanding metal stent in time to oral intake (1 ± 0 vs. 4.9 ± 0.6 days, p = 0.0001 and in-hospital stay (0.94 ± 1.18 vs. 7.8 ± 7.7 days, p = 0.0005. We did not find statistically significant differences with regards to long-term survival. Conclusions: in patients with malignant gastric outlet obstruction due to gastric cancer, endoscopic palliation with self-expanding metal stents provide a shorter interval to oral intake, shorter in-hospital stay and lower rate of complications.Introducción: los pacientes con cáncer gástrico tienen un tumor

Preoperative biliary drainage by plastic or self-expandable metal stents in patients with periampullary tumors: results of a randomized clinical study

Science.gov (United States)

Olsson, Greger; Frozanpor, Farshad; Lundell, Lars; Enochsson, Lars; Ansorge, Christoph; Del Chiaro, Marco; Reuterwall-Hansson, Marcus; Shetye, Alysha; Arnelo, Urban

2017-01-01

Background and study aims  Preoperative biliary drainage in patients with periampullary tumors and jaundice has been popularized to improve the quality of life and minimize the risks associated with subsequent radical surgery. The aim of this study was to investigate the possible superiority of self-expandable metal stents (SEMS) over plastic stents, by comparing the amount of bacteria in intraoperatively collected bile and using this variable as a proxy for the efficacy of the respective biliary drainage modalities. Patients and methods  In this randomized clinical trial, 92 patients with obstructive jaundice were enrolled; 45 were allocated to the plastic stent group and 47 to the SEMS group. The primary outcome was the extent and magnitude of biliary bacterial growth at the time of surgical exploration. Secondary outcomes were: macroscopic grading of inflammation of the stented bile ducts, occurrence of adverse events after stenting, stent dysfunction, recognized surgical complexities, and incidence of postoperative complications. Results  The patients were well matched regarding clinical and disease-specific characteristics. At surgery, there were no group differences in the bacterial amount and composition of the bile cultures or the perceived difficulty of surgical dissection. During the preoperative biliary drainage period, more instances of stent dysfunction requiring stent replacement were recorded in the plastic stent group (19 % vs. 0 %; P  = 0.03). Postoperative complications in patients who underwent curative surgery were more common in patients with plastic stents (72 % vs. 52 %), among which clinically significant leakage from the pancreatic anastomoses seemed to predominate (12 % vs. 3.7 %); however, none of these differences in postoperative adverse events reached statistical significance. Conclusion  This randomized clinical study was unable to demonstrate any superiority of SEMS in the efficacy of preoperative bile

Fundamentals of radiation materials science metals and alloys

CERN Document Server

Was, Gary S

2017-01-01

The revised second edition of this established text offers readers a significantly expanded introduction to the effects of radiation on metals and alloys. It describes the various processes that occur when energetic particles strike a solid, inducing changes to the physical and mechanical properties of the material. Specifically it covers particle interaction with the metals and alloys used in nuclear reactor cores and hence subject to intense radiation fields. It describes the basics of particle-atom interaction for a range of particle types, the amount and spatial extent of the resulting radiation damage, the physical effects of irradiation and the changes in mechanical behavior of irradiated metals and alloys. Updated throughout, some major enhancements for the new edition include improved treatment of low- and intermediate-energy elastic collisions and stopping power, expanded sections on molecular dynamics and kinetic Monte Carlo methodologies describing collision cascade evolution, new treatment of t...

17 CFR 31.28 - Self-regulatory organization adoption and surveillance of minimum financial, cover, segregation...

Science.gov (United States)

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Self-regulatory organization... TRANSACTIONS § 31.28 Self-regulatory organization adoption and surveillance of minimum financial, cover, segregation and sales practice requirements. (a) Each self-regulatory organization must adopt, and submit for...

Kinetics of self-interstitial migration in bcc and fcc transition metals

Science.gov (United States)

Bukkuru, S.; Bhardwaj, U.; Srinivasa Rao, K.; Rao, A. D. P.; Warrier, M.; Valsakumar, M. C.

2018-03-01

Radiation damage is a multi-scale phenomenon. A thorough understanding of diffusivities and the migration energies of defects is a pre-requisite to quantify the after-effects of irradiation. We investigate the thermally activated mobility of self-interstitial atom (SIA) in bcc transition metals Fe, Mo, Nb and fcc transition metals Ag, Cu, Ni, Pt using molecular dynamics (MD) simulations. The self-interstitial diffusion involves various mechanisms such as interstitialcy, dumbbell or crowdion mechanisms. Max-Space Clustering (MSC) method has been employed to identify the interstitial and its configuration over a wide range of temperature. The self-interstitial diffusion is Arrhenius like, however, there is a slight deviation at high temperatures. The migration energies, pre-exponential factors of diffusion and jump-correlation factors, obtained from these simulations can be used as inputs to Monte Carlo simulations of defect transport. The jump-correlation factor shows the degree of preference of rectilinear or rotational jumps. We obtain the average jump-correlation factor of 1.4 for bcc metals and 0.44 for fcc metals. It indicates that rectilinear jumps are preferred in bcc metals and rotational jumps are preferred in fcc metals.

The expanding universe: an introduction

OpenAIRE

Pössel, Markus

2017-01-01

An introduction to the physics and mathematics of the expanding universe, using no more than high-school level / undergraduate mathematics. Covered are the basics of scale factor expansion, the dynamics of the expanding universe, various distance concepts and the generalized redshift-luminosity relation, among other topics.

A novel self-expanding fully retrievable intracranial stent (SOLO): experience in nine procedures of stent-assisted aneurysm coil occlusion

International Nuclear Information System (INIS)

Liebig, Thomas; Henkes, Hans; Reinartz, Joerg; Miloslavski, Elina; Kuehne, Dietmar

2006-01-01

The endovascular treatment of large and broad-necked aneurysms may require the use of a remodelling balloon or a stent system to achieve proper occlusion while maintaining the patency of the parent vessel. With the advent of self-expanding stents that can be delivered through a microcatheter, this kind of treatment has improved and problems with the previously used balloon expandable stents have largely been overcome. However, rigidity, insufficient trackability, and limited or non-existent retrievability may still restrict the application of self-expanding stents in some situations. Recently, a stent system with a new and different design has been introduced. This stent is highly flexible, fully retrievable, and can be delivered through a standard 0.021-inch microcatheter without a wire. We describe the first nine cases of stent-assisted coil occlusion of intracranial aneurysms with the use of this stent system. Between May and June of 2004, nine patients with large or broad-necked aneurysms were treated in two endovascular centres. The anatomy of the aneurysms and parent vessels, technical details of the procedure, performance of the stent system, and follow-up results were evaluated. In all procedures, the SOLO stent could be introduced without difficulty, in one procedure after positioning of a different self-expanding stent system had failed due to vessel tortuosity. Overlapping stents were placed in one patient and stent retrieval or repositioning was successfully performed in two procedures. There was no interference or limitation of subsequent coil occlusion after stenting. With regard to the stent, immediate postprocedure and follow-up angiograms were unremarkable in terms of thromboembolic events and signs of intimal hyperplasia. From our experience, we conclude that the SOLO stent shows satisfactory performance overall. Its unique design gives the stent properties that may help overcome some of the difficulties experienced with other self-expanding

Self-expandable metal stents for relieving malignant colorectal obstruction: short-term safety and efficacy within 30 days of stent procedure in 447 patients.

Science.gov (United States)

Meisner, Søren; González-Huix, Ferran; Vandervoort, Jo G; Goldberg, Paul; Casellas, Juan A; Roncero, Oscar; Grund, Karl E; Alvarez, Alberto; García-Cano, Jesús; Vázquez-Astray, Enrique; Jiménez-Pérez, Javier

2011-10-01

The self-expandable metal stent (SEMS) can alleviate malignant colonic obstruction and avoid emergency decompressive surgery. To document performance, safety, and effectiveness of colorectal stents used per local standards of practice in patients with malignant large-bowel obstruction to avoid palliative stoma surgery in incurable patients (PAL) and facilitate bowel decompression as a bridge to surgery for curable patients (BTS). Prospective clinical cohort study. Two global registries with 39 academic and community centers. This study involved 447 patients with malignant colonic obstruction who received stents (255 PAL, 182 BTS, 10 no indication specified). Colorectal through-the-scope SEMS placement. The primary endpoint was clinical success at 30 days, defined as the patient's ability to maintain bowel function without adverse events related to the procedure or stent. Secondary endpoints were procedural success, defined as successful stent placement in the correct position, symptoms of persistent or recurrent colonic obstruction, and complications. The procedural success rate was 94.8% (439/463), and the clinical success rates were 90.5% (313/346) as assessed on a per protocol basis and 71.6% (313/437) as assessed on an intent-to-treat basis. Complications included 15 (3.9%) perforations, 3 resulting in death, 7 (1.8%) migrations, 7 (1.8%) cases of pain, and 2 (0.5%) cases of bleeding. No control group. No primary endpoint analysis data for 25% of patients. This largest multicenter, prospective study of colonic SEMS placement demonstrates that colonic SEMSs are safe and highly effective for the short-term treatment of malignant colorectal obstruction, allowing most curable patients to have 1-step resection without stoma and providing most incurable patients minimally invasive palliation instead of surgery. The risk of complications, including perforation, was low. Copyright © 2011 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All

Expanded Organic Building Units for the Construction of Highly Porous Metal-Organic Frameworks

NARCIS (Netherlands)

Kong, G.Q.; Han, Z.D.; He, Y.; Qu, S.; Zhou, W.; Yildirim, T.; Krishna, R.; Zou, C.; Chen, B.; Wu, C.D.

2013-01-01

wo new organic building units that contain dicarboxylate sites for their self-assembly with paddlewheel [Cu2(CO2)4] units have been successfully developed to construct two isoreticular porous metal-organic frameworks (MOFs), ZJU-35 and ZJU-36, which have the same tbo topologies (Reticular Chemistry

Long-term safety and outcome of a temporary self-expanding metallic stent for achalasia: a prospective study with a 13-year single-center experience

International Nuclear Information System (INIS)

Zhao, Jun-Gong; Li, Yong-Dong; Li, Ming-Hua; Shang, Ke-Zhong; Cheng, Ying-Sheng; Chen, Ni-Wei; Chen, Wei-Xiong

2009-01-01

To prospectively evaluate the long-term clinical safety and efficacy of a newly designed self-expanding metallic stent (SEMS) in the treatment of patients with achalasia. Seventy-five patients with achalasia were treated with a temporary SEMS with a 30-mm diameter. The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4-5 days after stent placement. Follow-up data focused on dysphagia score, technique and clinical success, clinical remissions and failures, and complications and was performed at 6 months, 1 year, and within 3 to 5 years, 5 to 8 years, 8 to 10 years, and >10 years postoperatively. Stent placement was technically successful in all patients. Complications included stent migration (n=4, 5.33%), chest pain (n=28, 38.7%), reflux (n=15, 20%), and bleeding (n=9, 12%). No perforation or 30-day mortality occurred. Clinical success was achieved in all patients 1 month after stent removal. The overall remission rates at 6 months, 1, 1-3, 3-5, 5-8, 8-10, and >10 year follow-up periods were 100%, 96%, 93.9%, 90.9%, 100%, 100%, and 83.3%, respectively. Stent treatment failed in six patients, and the overall remission rate in our series was 92%. The median and mean primary patencies were 2.8 ± 0.28 years (95% CI: 2.25-3.35) and 4.28 ± 0.40 years (95% CI: 3.51-5.05), respectively. The use of temporary SEMSs with 30-mm diameter proved to be a safe and effective approach for managing achalasia with a long-term satisfactory clinical remission rate. (orig.)

Electronic structure and dynamics of metal and metal-covered surfaces

International Nuclear Information System (INIS)

Yang, Shu.

1992-01-01

The unoccupied electronic states of;Ni(111) and Al(111) have been studied using angle-resolved inverse-photoemission (IPE) spectroscopy. We have characterized the n = 1 image potential state on Ni(111) measuring an effective mass of m * /m = 1, consistent with recent two-photon photoemission results as well as theoretical calculations using a phase-analysis model, but differing considerably from the earlier angle-resolved IPE measurements. The bulk related features on Ni(111) observed in our experiment agree very well with an empirical Ni band structure calculation. On Al(111), we have conducted an extensive study of the image potential resonance using both angle-resolved IPE spectroscopy and tunneling spectroscopy with the scanning tunneling microscope. We have used Al as a testing case for both nearly-free-electron model and first-principles calculations were needed to obtain a semi-quantitative account of the bulk features of Al, a simple metal. Improved quantitative agreement occurred when excitation effects were considered. In addition, several surface resonance features have been identified and characterized on Al(111). We have also conducted a geometric structural investigation of a metal overlayer system, Ni/Cu(111), using high-resolution electron energy loss spectroscopy with CO as a probe molecule. The results indicate island formation and two-dimensional mixing at the initial stage of bimetallic interface formation. A new adsorption site with CO bonded to both Ni and Cu has been discovered on the Ni-Cu intermixed surface. IPE results for the Cu-covered Ni(111) surface show an enhanced angular range for the Cu image state. Finally, the unique ability of Auger-photoelectron coincidence spectroscopy to probing local valence electronic structure has been tested in a case study of TaC(111). A novel Auger decay channel has also been observed

[Evaluation of pollution of an urban area by level of heavy metals in snow cover].

Science.gov (United States)

Stepanova, N V; Khamitova, R Ia; Petrova, R S

2003-01-01

The goal of this study was to systematize various methodological approaches to evaluating the contamination of the snow cover with heavy metals (HM) by using Kazan, an industrial city with diversified industry, as an example. The findings suggest that it is necessary to characterize the contamination of the snow cover by the actual entrance of an element per area unit of the snow cover for a definite period of time rather than by the concentration of TM in the volume unit of snow water (mg/l), which minimizes the uncertainties with spatial and temporary snow cover variations. The index of the maximum allowable entrance, which is of practical value, may be used to objectively calibrate the pollution of the snow cover, by estimating the amount of a coming element and its toxicity.

Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

International Nuclear Information System (INIS)

Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won

2016-01-01

To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m"2. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

Uranium Concentration of Contaminated Zone due to the Cover Depth for Self-Disposal

Energy Technology Data Exchange (ETDEWEB)

Koo, Dae Seo; Sung, Hyun Hee; Kim, Gye Nam; Kim, Seung Soo; Kim, Il Gook; Han, Gyu Seong; Choi, Jong Won [KAERI, Daejeon (Korea, Republic of)

2016-05-15

To acquire radiation dose under self disposal from them, the study on decontamination of some uranium contaminated soil and concrete wastes was performed using electrokinetic-electrodialytic. In this study, we evaluated radiation dose due to cover depth on contaminated zone such as uranium contaminated soil and concrete wastes under radiation dose limit using RESRAD Version 6.5. At first, the calculation of the radiation dose on the contaminated zone are carried out. The second, the uranium concentration of contaminated zone due to the cover depth are also analyzed. The uranium contaminated soil and concrete wastes under radiation dose limit by decontaminating them have application to self-disposal of contaminated zone. The area of contaminated zone is 1,500 m{sup 2}. The thickness of contaminated zone is 2 m. The length parallel to aquifer flow is 43.702m. The age of the residents on contaminated zone is 15 years old. The period of evaluation on the contaminated zone is from regulation exemption of uranium contaminated soil and concrete wastes till 1,000 years. The calculation of the radiation dose on contaminated zone are carried out. The uranium concentration of contaminated zone due to the cover depth was also analyzed. as the cover depth increases, the uranium concentration has an increasing trend. As the cover depth increases, radiation dose of a person has a decreasing trend. As the cover depth increases, the radiation dose of residents has also a decreasing trend.

Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

Directory of Open Access Journals (Sweden)

Birger Mensel

Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

[Fine mesh metal endoprostheses for treatment of extensive cervical and intrathoracic tracheomalacia].

Science.gov (United States)

Wilmes, E; Berger, H; Dienemann, H; Jolk, A

1994-01-01

The treatment of tracheal stenoses caused by tracheomalacia is mainly carried out by means of sleeve resection, tracheopexy with ring support or other tracheoplastic operative procedures. If patients cannot be treated by surgical operative strategies, conventional stents are usually used to dilate the trachea. The use of a self-expanding elastic metal prosthesis in 5 patients with tracheal airway obstruction caused by tracheomalacia proved to be a true alternative in the therapy of tracheobronchial stenoses. We report on the long term use of 5 patients with tracheal stenoses treated by implantation of elastic metal wallstents. The implantation of the stents resulted in immediate improvement in respiratory function in all 5 patients. None of the patients experienced complications secondary to the stent placement. The stents were well tolerated (long-time follow-up 26 months). The implantation of self-expanding metal stents type "wallstent" seems to offer alternative possibilities for the treatment of tracheomalacia.

Lightweight self-compacting concrete with light expanded clay aggregate (LECA

Directory of Open Access Journals (Sweden)

Heiza Khaled

2018-01-01

Full Text Available Lightweight concretes have been successfully applied in building constructions for many years due to their favorable material properties, particularly their low specific weight in connection with a high strength, a high capability of thermal insulation and a high durability. The development leading to lightweight self-compacting concrete (LWSCC represents an important advanced step within the recent years. This concrete combines the favorable properties of a lightweight concrete with those of a self-compacting concrete. Research work is aimed on development of (LWSCC with the use of light aggregates “Light expanded clay aggregate (LECA”. In this research, first by specific gravity factor method, twenty different mix designs of (LWSCC were cast and tested to find out the values of slump flow, J-ring , V-funnel and 28 day compressive strength. Based on the results obtained, the best mix design was selected for further investigation. This paper also focuses on studying the effect of changing the reinforcement ratio on reinforced two way slabs when the dimensions were kept constant.

Synthesis of Inorganic Nanocomposites by Selective Introduction of Metal Complexes into a Self-Assembled Block Copolymer Template

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Hiroaki Wakayama

2015-01-01

Full Text Available Inorganic nanocomposites have characteristic structures that feature expanded interfaces, quantum effects, and resistance to crack propagation. These structures are promising for the improvement of many materials including thermoelectric materials, photocatalysts, and structural materials. Precise control of the inorganic nanocomposites’ morphology, size, and chemical composition is very important for these applications. Here, we present a novel fabrication method to control the structures of inorganic nanocomposites by means of a self-assembled block copolymer template. Different metal complexes were selectively introduced into specific polymer blocks of the block copolymer, and subsequent removal of the block copolymer template by oxygen plasma treatment produced hexagonally packed porous structures. In contrast, calcination removal of the block copolymer template yielded nanocomposites consisting of metallic spheres in a matrix of a metal oxide. These results demonstrate that different nanostructures can be created by selective use of processes to remove the block copolymer templates. The simple process of first mixing block copolymers and magnetic nanomaterial precursors and then subsequently removing the block copolymer template enables structural control of magnetic nanomaterials, which will facilitate their applicability in patterned media, including next-generation perpendicular magnetic recording media.

Observation of self-sputtering in energetic condensation of metal ions

International Nuclear Information System (INIS)

Anders, Andre

2004-01-01

The condensation of energetic metal ions on a surface may cause self-sputtering even in the absence of substrate bias. Charge-state-averaged self-sputtering yields were determined for both zirconium and gold ions generated by a cathodic vacuum arc. Films were deposited on differently biased substrates exposed to streaming Zr and Au vacuum arc plasma. The self-sputtering yields for both metals were estimated to be about 0.05 in the absence of bias, and exceeding 0.5 when bias reached-50 V. These surprisingly high values can be reconciled with binary collision theory and molecular dynamics calculations taking high the kinetic and potential energy of vacuum arc ions into account

Self-trapping of helium in metals

International Nuclear Information System (INIS)

Wilson, W.D.; Bisson, C.L.; Baskes, M.I.

1981-01-01

Atomistic calculations are presented which demonstrate that helium atoms in a metal lattice are able to cluster with each other, producing vacancies and nearby self-interstitial defects. Even a small number of helium atoms is found to be sufficient to create these large distortions. As few as five interstitial helium can spontaneously produce a lattice vacancy and nearby self-interstitial. An eight-helium-atom cluster gives rise to two such defects, and 16 helium atoms to more than five self-interstitial vacancy pairs. It was noted that the self-interstitials prefer to agglomerate on the same ''side'' of the helium cluster rather than to spread themselves out uniformly. The binding energy of each additional helium atom to these clusters increases with helium concentration and the trap is apparently unsaturable. A rate theory using these atomistic binding energies has been used to calculate the kinetics of helium-bubble nucleation and growth. The results are consistent with measurements of the properties of helium resulting from tritium decay

Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes.

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Bae, Jichul; Benoit, Diane L; Watson, Alan K

2016-06-01

In southern Québec, supplement roadside ground covers (i.e. Trifolium spp.) struggle to establish near edges of major roads and thus fail to assist turf recruitment. It creates empty niches vulnerable to weed establishment such as common ragweed (Ambrosia artemisiifolia). We hypothesized that heavy metal stresses may drive such species shifts along roadside edges. A growth chamber experiment was conducted to assess effects of metals (Zn, Pb, Ni, Cu, and Cd) on germination and seedling behaviors of roadside weed (A. artemisiifolia) and ground cover legumes (Coronilla varia, Lotus corniculatus, and Trifolium arvense). All metals inhibited T. arvense germination, but the effect was least on A. artemisiifolia. Low levels of Pb and Ni promoted germination initiation of A. artemisiifolia. Germination of L. corniculatus was not affected by Zn, Pb, and Ni, but inhibited by Cu and Cd. Germination of C. varia was decreased by Ni, Cu, and Cd and delayed by Zn and Pb. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth. Seedling mortality was lowest in A. artemisiifolia but highest in T. arvense when exposed to the metal treatments. L. corniculatus and C. varia seedlings survived when subjected to high levels of Zn, Pb, and Cd. In conclusion, the successful establishment of A. artemisiifolia along roadside edges can be associated with its greater tolerance of heavy metals. The findings also revealed that L. corniculatus is a potential candidate for supplement ground cover in metal-contaminated roadside edges in southern Québec, especially sites contaminated with Zn and Pb. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-interstitial atoms in metals

International Nuclear Information System (INIS)

Schilling, W.

1978-01-01

The present state of knowledge and understanding of the properties of self-interstitial atoms (SIAs) in metals is reviewed. Special emphasis is given to a discussion of the structure of SIAs and those properties which relate to structure such as relaxation volumes, elastic polarizabilities, defect vibrations, geometry of jump processes, and elastic interactions. The present experimental status with respect to these properties is summarized, and the basic theoretical concepts for their understanding are presented as simply as possible. (Auth.)

Covered Metallic Stents With an Anti-Migration Design vs. Uncovered Stents for the Palliation of Malignant Gastric Outlet Obstruction: A Multicenter, Randomized Trial

Science.gov (United States)

Lee, Hyuk; Min, Byung-Hoon; Lee, Jeong Hoon; Shin, Cheol Min; Kim, Younjoo; Chung, Hyunsoo; Lee, Sang Hyub

2015-01-01

OBJECTIVES: Previous studies reported comparable stent patency between covered self-expandable metallic stents (SEMS) and uncovered SEMS (UCS) for palliation of malignant gastric outlet obstruction (GOO). The aim of this study was to evaluate the efficacy and safety of the newly developed WAVE-covered SEMS (WCS), which has an anti-migration design, compared with UCS in gastric cancer patients with symptomatic GOO. METHODS: A total of 102 inoperable gastric cancer patients with symptomatic GOO were prospectively enrolled from five referral centers and randomized to undergo UCS or WCS placement. Stent patency and recurrence of obstructive symptoms were assessed at 8 weeks and 16 weeks after stent placement. RESULTS: At the 8-week follow-up, both stent patency rates (72.5% vs. 62.7%) and re-intervention rates (19.6% vs. 19.6%) were comparable between the WCS and the UCS groups. Both stent stenosis (2.4% vs. 8.1%) and migration rates (9.5% vs. 5.4%) were comparable between WCS and UCS groups. At the 16-week follow-up, however, the WCS group had a significantly higher stent patency rate than the UCS group (68.6% vs. 41.2%). Re-intervention rates in the WCS and UCS groups were 23.5% and 39.2%, respectively. Compared with the UCS group, the WCS group had a significantly lower stent restenosis rate (7.1% vs. 37.8%) and a comparable migration rate (9.5% vs. 5.4%). Overall stent patency was significantly longer in the WCS group than in the UCS group. No stent-associated significant adverse events occurred in either the WCS or UCS groups. In the multivariate analysis, WCS placement and chemotherapy were identified as independent predictors of 16-week stent patency. CONCLUSIONS: WCS group showed comparable migration rate and significantly more durable long-term stent patency compared with UCS group for the palliation of GOO in patients with inoperable gastric cancer. PMID:26372507

Expand Your Horizon: A programme that improves body image and reduces self-objectification by training women to focus on body functionality.

Science.gov (United States)

Alleva, Jessica M; Martijn, Carolien; Van Breukelen, Gerard J P; Jansen, Anita; Karos, Kai

2015-09-01

This study tested Expand Your Horizon, a programme designed to improve body image by training women to focus on the functionality of their body using structured writing assignments. Eighty-one women (Mage=22.77) with a negative body image were randomised to the Expand Your Horizon programme or to an active control programme. Appearance satisfaction, functionality satisfaction, body appreciation, and self-objectification were measured at pretest, posttest, and one-week follow-up. Following the intervention, participants in the Expand Your Horizon programme experienced greater appearance satisfaction, functionality satisfaction, and body appreciation, and lower levels of self-objectification, compared to participants in the control programme. Partial eta-squared effect sizes were of small to medium magnitude. This study is the first to show that focusing on body functionality can improve body image and reduce self-objectification in women with a negative body image. These findings provide support for addressing body functionality in programmes designed to improve body image. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficacy of a Self-Expandable Porous Stent as the Sole Curative Treatment for Extracranial Carotid Pseudoaneurysms.

Science.gov (United States)

Chen, Peng Roc; Edwards, Nancy J; Sanzgiri, Aditya; Day, Arthur L

2016-04-01

Extracranial carotid pseudoaneurysms are uncommon vascular lesions. Even with conservative management complications can happen, such as delayed cerebral embolization or symptoms due to flow limitation. Although endovascular therapy can be curative, literature demonstrating a preferred technique is scant. Our goal was to evaluate the use of 1 technique only-the deployment of overlapping self-expandable porous stents-to treat a series of extracranial carotid pseudoaneurysms. From 2008 to 2014, 14 consecutive cases of symptomatic extracranial carotid pseudoaneurysms were managed with single or multilayer porous stents at our institution. Each patient underwent a standardized angiographic follow-up at 6 months. Twelve patients also received a follow-up computed tomography angiogram at 12 months, and yearly thereafter (median radiographic follow-up, 38 months). The total clinical follow-up period ranged between 6 and 69 months (median, 46 months). In our series, each of the extracranial carotid pseudoaneurysms appeared to be the result of carotid artery dissection with associated carotid stenosis at the origin of every pseudoaneurysm. Endovascular treatment consisted of 1-3 layers of self-expandable porous stents placed without balloon angioplasty. Immediately after stenting angiographic images were notable for stagnant opacification of the pseudoaneurysm through the stent(s). All pseudoaneurysms were completely obliterated by the 6-month follow-up angiogram and remained so throughout the radiographic follow-up period. Complications were minimal, consisting of 1 patient developing a mild Horner's syndrome after treatment that resolved during clinical follow-up. Extracranial carotid pseudoaneurysms can be successfully obliterated with the use of porous, self-expandable stents. Copyright © 2016 Elsevier Inc. All rights reserved.

Midterm to long-term safety and efficacy of self-expandable nitinol stent implantation for coarctation of aorta in adults.

Science.gov (United States)

Haji Zeinali, Ali Mohammad; Sadeghian, Mohammad; Qureshi, Shakeel A; Ghazi, Payam

2017-09-01

Endovascular treatment of coarctation of aorta (CoA) by self-expandable Nitinol stents is one of the recognized treatment methods and may be an alternative to surgery or balloon-expandable stent implantation for CoA but there is little information about midterm to long term results of self-expandable stents. Sixty-two patients with CoA (40 men), with a mean age of 30.7 ± 11 years, (range 17-63 years) underwent stent implantation with Optimed self-expandable Nitinol stents between 2005 and 2014. Successful outcome was defined as peak systolic pressure gradient ≤20 mmHg after stent implantation. The patients were followed-up clinically and by echocardiography and in patients, in whom there was suspicion of recoarctation, CT angiography or recatheterization was performed. 65 stents were successfully implanted in all 62 patients. Peak systolic pressure gradient decreased from mean 62.4 ± 18 mmHg (range 35-100 mmHg) to mean 2.8 ± 5 mmHg (range 0-15 mmHg; P Stent displacement occurred in 3 patients during the procedure. These were managed successfully by an overlapping second stent. None of the patients had major complications such as aortic dissection, rupture, or vascular access problems. In follow up, only three patients had recoarctation, and two of these were managed successfully by balloon redilation or further stenting 16 and 18 months after the first procedure and one patient refused reintervention. There were two deaths, unrelated to the procedure, 12 and 78 months after the initial intervention. Follow-up of a mean of 45.5 ± 17 months (range 12-105 months) demonstrated no evidence of aneurysm formation or stent fracture. Self-expandable nitinol stents for the treatment of native and recurrent CoA is safe and has good efficacy with acceptable midterm to long-term outcome. © 2017 Wiley Periodicals, Inc.

Nuclear reactor pressure vessel with an inner metal coating covered with a high temperature resistant thermal insulator

International Nuclear Information System (INIS)

1974-01-01

The thermal insulator covering the metal coating of a reactor vessel is designed for resisting high temperatures. It comprises one or several porous layers of ceramic fibers or of stacked metal foils, covered with a layer of bricks or ceramic tiles. The latter are fixed in position by fasteners comprising pins fixed to the coating and passing through said porous layers and fasteners (nut or bolts) for individually fixing the bricks to said pins, whereas ceramic plugs mounted on said bricks or tiles provide for the thermal insulation of the pins and of the nuts or bolts; such a thermal insulation can be applied to high-temperature reactors or to fast reactors [fr

Dysphagia with malignant stricture of esophagogastric junction: treatment with self-expandable nitinol stent

International Nuclear Information System (INIS)

Lee, Choon Hyeong; Oh, Joo Hyeong; Yoon, Yup

1995-01-01

To evaluate the effectiveness, patency and safety of a self-expandable nitinol stent for palliative treatment of malignant stricture of gastroesophageal junction. An esophageal stent was inserted in five consecutive patients with malignant stricture of esophagogastric junction. Histologically, four cases were adenocarcinoma, and one was squamous cell carcinoma. The location and severity of stricture were evaluated with gastrografin just before stent insertion. In one patient with past subtotal gastrectomy, esophagography revealed fistulous fract at stricture site. No technical failure or procedural complications occurred, and improvement of dysphagia was noted in all patients soon after stent insertion. On follow up esophagograms performed 3 to 7 days after stent insertion, all stents were completely expanded and unchanged in positions. In one patient with fistulous connection at stricture site, esophagogram immediately after the procedure revealed complete occlusion of the fistula. Three patients died within 4, 7 and 8 consecutive months after stent insertion. Two patients are alive maintaining adequate body weight and passing most diet. Seft-expandable nitinol stent with it's good longitudinal flexibility and efficient radial force was effective in the palliative treatment of dysphagia in patient with malignant stricture at esophagogastric junction

Dysphagia with malignant stricture of esophagogastric junction: treatment with self-expandable nitinol stent

Energy Technology Data Exchange (ETDEWEB)

Lee, Choon Hyeong; Oh, Joo Hyeong; Yoon, Yup [Kyung Hee University Hospital, Seoul (Korea, Republic of)

1995-02-15

To evaluate the effectiveness, patency and safety of a self-expandable nitinol stent for palliative treatment of malignant stricture of gastroesophageal junction. An esophageal stent was inserted in five consecutive patients with malignant stricture of esophagogastric junction. Histologically, four cases were adenocarcinoma, and one was squamous cell carcinoma. The location and severity of stricture were evaluated with gastrografin just before stent insertion. In one patient with past subtotal gastrectomy, esophagography revealed fistulous fract at stricture site. No technical failure or procedural complications occurred, and improvement of dysphagia was noted in all patients soon after stent insertion. On follow up esophagograms performed 3 to 7 days after stent insertion, all stents were completely expanded and unchanged in positions. In one patient with fistulous connection at stricture site, esophagogram immediately after the procedure revealed complete occlusion of the fistula. Three patients died within 4, 7 and 8 consecutive months after stent insertion. Two patients are alive maintaining adequate body weight and passing most diet. Seft-expandable nitinol stent with it's good longitudinal flexibility and efficient radial force was effective in the palliative treatment of dysphagia in patient with malignant stricture at esophagogastric junction.

Use of Self-Expanding Stents for the Treatment of Vertebral Artery Ostial Stenosis: a Single Center Experience

International Nuclear Information System (INIS)

Chung, Sun Young; Lee, Deok Hee; Choi, Jin Woo; Choi, Byung Se; In, Hyun Sin; Kim, Sun Mi; Choi, Choong Gon; Kim, Sang Joon; Suh, Dae Chul

2010-01-01

To evaluate our early experience using self-expanding stents to treat atherosclerotic vertebral artery ostial stenosis (VAOS), with respect to technical feasibility and clinical and imaging follow-up results. A total of 20 lesions in 20 patients underwent stenting of the VAOS using a self-expanding stent (Precise RX; Cordis Neurovascular, Miami Lakes, FL). Two patients were asymptomatic. We analyzed the technical success rate, causes of technical failure, occurrence of any vascular or neurological event, and the occurrence of any neurological abnormality or in-stent restenosis (ISR) seen on follow-up. The imaging follow-up was performed with Doppler ultrasound (DUS) as a primary screening modality. One instance of technical failure was caused by failure of the guidewire passage. The stent diameter was 5 mm, and post-stenting balloon dilatations were necessary in all cases. Stent misplacement requiring placement of an additional stent occurred in four cases. Following a 14.8 month average clinical follow-up time, two patients showed anterior circulation ischemia, which was not attributed to the VAOS we treated. Following a 13.7 month average DUS follow-up, five patients showed a mild degree of diffuse or focal intimal thickening in the stent lumen; however, none of the stenosis showed luminal loss of more than 50% and no stent fracture was noted. The use of self-expanding stents for treating VAOS was technically feasible and helped to improve artery patency during our limited follow-up interval

Self-made metal stent in treatment of nasolacrimal duct obstruction

International Nuclear Information System (INIS)

Du Wei; Pang Ruilin; Luo Gang; Gu Jingchuan; Gong Yongxiang

2003-01-01

Objective: To evaluate application of self-made metal stent in treatment of nasolacrimal duct obstruction. Methods: In total 15 cases, self-made metal stents made of stainless steel wire were implanted in 18 obstructed nasolacrimal ducts. The lacrimal passages were rinsed and re-canalized followed by antegrade inserting the guide wire from upper dacryon. A dilator was inserted over the guide wire, and then a stent was released from a sheath into the impaired section of nasolacrimal duct. Dacryocystography was performed before and after the interventional procedure. Results: Dacryocystography showed patent nasolacrimal duct after treatment. Epiphora disappeared completely in 11 cases (13 ducts), improved in 4 cases (5 ducts). These cases had been followed up for 61-219 days (167 days in average). Relapse was found in 2 cases (2 ducts) in three months. Those 2 stents were removed by surgical procedure and found occluded by granulation. Conclusion: Interventional placement of the self-made metal stent is a simple, safe, low-cost and effective treatment of the nasolacrimal duct obstruction

On the self-diffusion process in liquid metals and alloys by the radioactive tracer method

International Nuclear Information System (INIS)

Ganovici, L.

1978-01-01

A theoretical and experimental study of self-diffusion process in liquid metals and alloys is presented. There are only a few pure metals for which diffusion coefficients in a liquid state are known. The thesis aims at increasing the number of liquid metals for which diffusion coefficients are available, by determining these values for liquids: Cd, Tl, Sb and Te. The self-diffusion coefficients of Te in some tellurium based liquid alloys such as Tl 2 Te, PbTe and Bi 90 Te 10 were also determined. Self-diffusion coefficients have been measured using two radioactive tracer methods: a) the capillary-reservoir method; b) the semi-infinite capillary method. The self-diffusion coefficients were derived from the measured radioactive concentration profile, using the solutions of Fick's second law for appropriate initial and limit conditions. The temperature dependence study of self-diffusion coefficients in liquids Cd, Tl, Sb and Te, was used to check some theoretical models on the diffusion mechanism in metallic melts. The experimental diffusion data interpreted in terms of the Arrhenius type temperature dependence, was used to propose two simple empiric relations for determining self diffusion coefficients of group I liquid metals and for liquid semi-metals. It was established a marked decrease of self-diffusion coefficients of liquid Te close to the solidification temperature. The diffusivity of Te in liquid Tl 2 Te points to an important decrease close to the solidification temperature. A simplified model was proposed for the diffusion structural unit in this alloy and the hard sphere model for liquid metals was checked by comparing the theoretical and experimental self-diffusion coefficients. (author)

Study design and rationale of the 'Balloon-Expandable Cobalt Chromium SCUBA Stent versus Self-Expandable COMPLETE-SE Nitinol Stent for the Atherosclerotic ILIAC Arterial Disease (SENS-ILIAC Trial) Trial': study protocol for a randomized controlled trial.

Science.gov (United States)

Choi, Woong Gil; Rha, Seung Woon; Choi, Cheol Ung; Kim, Eung Ju; Oh, Dong Joo; Cho, Yoon Hyung; Park, Sang Ho; Lee, Seung Jin; Hur, Ae Yong; Ko, Young Guk; Park, Sang Min; Kim, Ki Chang; Kim, Joo Han; Kim, Min Woong; Kim, Sang Min; Bae, Jang Ho; Bong, Jung Min; Kang, Won Yu; Seo, Jae Bin; Jung, Woo Yong; Cho, Jang Hyun; Kim, Do Hoi; Ahn, Ji Hoon; Kim, Soo Hyun; Jang, Ji Yong

2016-06-25

The self-expandable COMPLETE™ stent (Medtronic) has greater elasticity, allowing it to regain its shape after the compression force reduces, and has higher trackability, thus is easier to maneuver through tortuous vessels, whereas the balloon-expandable SCUBA™ stent (Medtronic) has higher radial stiffness and can afford more accurate placement without geographic miss, which is important in aortoiliac bifurcation lesions. To date, there have been no randomized control trials comparing efficacy and safety between the self-expanding stent and balloon-expandable stent in advanced atherosclerotic iliac artery disease. The purpose of our study is to examine primary patency (efficacy) and incidence of stent fracture and geographic miss (safety) between two different major representative stents, the self-expanding nitinol stent (COMPLETE-SE™) and the balloon-expanding cobalt-chromium stent (SCUBA™), in stenotic or occlusive iliac arterial lesions. This trial is designed as a prospective, randomized, multicenter trial to demonstrate a noninferiority of SCUBA™ stent to COMPLETE-SE™ stent following balloon angioplasty in iliac arterial lesions, and a total of 280 patients will be enrolled. The primary end point of this study is the rate of primary patency in the treated segment at 12 months after intervention as determined by catheter angiography, computed tomography angiography, or duplex ultrasound. The SENS-ILIAC trial will give powerful insight into whether the stent choice according to deployment mechanics would impact stent patency, geographic miss, or stent fracture in patients undergoing stent implantation in iliac artery lesions. National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier: NCT01834495 ), registration date: May 8, 2012.

Nanostructural self-organization and dynamic adaptation of metal-polymer tribosystems

Science.gov (United States)

Mashkov, Yu. K.

2017-02-01

The results of investigating the effect of nanosize modifiers of a polymer matrix on the nanostructural self-organization of polymer composites and dynamic adaptation of metal-polymer tribosystems, which considerably affect the wear resistance of polymer composite materials, have been analyzed. It has been shown that the physicochemical nanostructural self-organization processes are developed in metal-polymer tribosystems with the formation of thermotropic liquid-crystal structures of the polymer matrix, followed by the transition of the system to the stationary state with a negative feedback that ensures dynamic adaptation of the tribosystem to given operating conditions.

[Snow cover pollution monitoring in Ufa].

Science.gov (United States)

Daukaev, R A; Suleĭmanov, R A

2008-01-01

The paper presents the results of examining the snow cover polluted with heavy metals in the large industrial town of Ufa. The level of man-caused burden on the snow cover of the conventional parts of the town was estimated and compared upon exposure to a wide range of snow cover pollutants. The priority snow cover pollutants were identified among the test heavy metals.

Membrane-like structure in the urinary bladder neck of a young cat: diagnosis and treatment using balloon dilatation and a balloon-expandable metallic stent

Directory of Open Access Journals (Sweden)

Matias Ruiz-Drebing

2017-10-01

Full Text Available Case summary A 33-month-old, spayed female domestic shorthair cat was referred to the Animal Health Trust for the investigation of urinary incontinence and straining to urinate. A membrane-like structure was detected in the bladder neck, which caused partial obstruction of the urinary bladder. A combination of different imaging techniques, including ultrasonography, radiography, CT and fluoroscopy, was essential in the diagnosis, surgical planning and treatment of this intravesicular stricture. During retrograde vaginourethrocystogram, unexpected subcapsular accumulation of contrast medium was seen around both kidneys on radiographs and confirmed with CT. Three different treatments were performed, including surgical debridement, balloon dilatation and placement of a self-expanding metallic stent across the stricture. Histopathology of the membrane was unable to differentiate whether the lesion was congenital or acquired. No urinary incontinence was observed 5 months after placement of the metallic stent. Relevance and novel information This is the first reported case using fluoroscopic-guided balloon dilatation of the bladder neck for the treatment of a bladder neck stricture. Presence of renal subcapsular contrast medium secondary to a retrograde vaginourethrocystogram due to partial obstruction at the bladder neck in a cat has not been previously described.

Clinical outcomes of self-expandable stent placement for benign esophageal diseases: A pooled analysis of the literature

NARCIS (Netherlands)

van Halsema, Emo E.; van Hooft, Jeanin E.

2015-01-01

AIM: To analyze the outcomes of self-expandable stent placement for benign esophageal strictures and benign esophageal leaks in the literature. METHODS: The PubMed, Embase and Cochrane databases were searched for relevant articles published between January 2000 and July 2014. Eight prospective

Poly (Ethylene Glycol)-Based Hydrogels as Self-Inflating Tissue Expanders with Tunable Mechanical and Swelling Properties.

Science.gov (United States)

Jamadi, Mahsa; Shokrollahi, Parvin; Houshmand, Behzad; Joupari, Mortaza Daliri; Mashhadiabbas, Fatemeh; Khademhosseini, Ali; Annabi, Nasim

2017-08-01

Tissue expansion is used by plastic/reconstructive surgeons to grow additional skin/tissue for replacing or repairing lost or damaged soft tissues. Recently, hydrogels have been widely used for tissue expansion applications. Herein, a self-inflating tissue expander blend composition from three different molecular weights (2, 6, and 10 kDa) of poly (ethylene glycol) diacrylate (PEGDA) hydrogel with tunable mechanical and swelling properties is presented. The in vitro results demonstrate that, of the eight studied compositions, P6 (PEGDA 6 kDa:10 kDa (50:50)) and P8 (PEGDA 6 kDa:10 kDa (35:65)) formulations provide a balance of mechanical property and swelling capability suitable for tissue expansion. Furthermore, these expanders can be compressed up to 60% of their original height and can be loaded and unloaded cyclically at least ten times with no permanent deformation. The in vivo results indicate that these two engineered blend compositions are capable to generate a swelling pressure sufficient to dilate the surrounding tissue while retaining their original shape. The histological analyses reveal the formation of fibrous capsule at the interface between the implant and the subcutaneous tissue with no signs of inflammation. Ultimately, controlling the PEGDA chain length shows potential for the development of self-inflating tissue expanders with tunable mechanical and swelling properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Circumferential and fusiform intracranial aneurysms: reconstructive endovascular treatment with self-expandable stents

Energy Technology Data Exchange (ETDEWEB)

Lubicz, Boris [Erasme University Hospital, Department of Neuroradiology, Brussels (Belgium); Hopital Erasme, Service de Radiologie (EA 2691), Brussels (Belgium); Collignon, Laurent; Baleriaux, Danielle [Erasme University Hospital, Department of Neuroradiology, Brussels (Belgium); Lefranc, Florence; Bruneau, Michael; Brotchi, Jacques; Witte, Olivier de [Erasme University Hospital, Department of Neurosurgery, Brussels (Belgium)

2008-06-15

We report our experience with endovascular treatment (EVT) of circumferential and fusiform intracranial aneurysms by a reconstructive approach with self-expandable stents. A retrospective review of our prospectively maintained database identified all circumferential and fusiform aneurysms treated by a reconstructive endovascular approach over a 3-year period. Clinical charts, procedural data, and angiographic results were reviewed. From April 2004 to May 2007, 13 patients were identified, of whom 12 were asymptomatic and 1 presented with a subarachnoid hemorrhage. Two patients with an aneurysm {<=}2 mm were treated by stent-within-stent placement without coiling (group 1). In 11 patients with a larger aneurysm, stenting with subsequent coiling was performed (group 2). In this latter approach, a balloon was temporarily inflated within the stent to ensure safe coil delivery. All patients showed an excellent clinical outcome. Asymptomatic procedural complications occurred in three patients, two with cervical internal carotid artery dissection and one with retroperitoneal hematoma. In patients of group 1, the aneurysm had completely disappeared at 6 months. In patients of group 2, aneurysm occlusion was complete in three and incomplete in eight. Follow-up angiography in 12 patients showed four with further thrombosis, six with stable results, and two with minor recanalization. Circumferential and fusiform intracranial aneurysms may be treated by a reconstructive endovascular approach with self-expandable stents. In small aneurysms, a stent-within-stent technique is effective, whereas stenting and subsequent coiling is indicated in larger aneurysms. This therapeutic protocol is associated with good clinical and anatomical results. (orig.)

INSIGHTS INTO PRE-ENRICHMENT OF STAR CLUSTERS AND SELF-ENRICHMENT OF DWARF GALAXIES FROM THEIR INTRINSIC METALLICITY DISPERSIONS

International Nuclear Information System (INIS)

Leaman, Ryan

2012-01-01

Star clusters are known to have smaller intrinsic metallicity spreads than dwarf galaxies due to their shorter star formation timescales. Here we use individual spectroscopic [Fe/H] measurements of stars in 19 Local Group dwarf galaxies, 13 Galactic open clusters, and 49 globular clusters to show that star cluster and dwarf galaxy linear metallicity distributions are binomial in form, with all objects showing strong correlations between their mean linear metallicity Z-bar and intrinsic spread in metallicity σ(Z) 2 . A plot of σ(Z) 2 versus Z-bar shows that the correlated relationships are offset for the dwarf galaxies from the star clusters. The common binomial nature of these linear metallicity distributions can be explained with a simple inhomogeneous chemical evolution model, where the star cluster and dwarf galaxy behavior in the σ(Z) 2 - Z-bar diagram is reproduced in terms of the number of enrichment events, covering fraction, and intrinsic size of the enriched regions. The inhomogeneity of the self-enrichment sets the slope for the observed dwarf galaxy σ(Z) 2 - Z-bar correlation. The offset of the star cluster sequence from that of the dwarf galaxies is due to pre-enrichment, and the slope of the star cluster sequence represents the remnant signature of the self-enriched history of their host galaxies. The offset can be used to separate star clusters from dwarf galaxies without a priori knowledge of their luminosity or dynamical mass. The application of the inhomogeneous model to the σ(Z) 2 - Z-bar relationship provides a numerical formalism to connect the self-enrichment and pre-enrichment between star clusters and dwarf galaxies using physically motivated chemical enrichment parameters. Therefore we suggest that the σ(Z) 2 - Z-bar relationship can provide insight into what drives the efficiency of star formation and chemical evolution in galaxies, and is an important prediction for galaxy simulation models to reproduce.

Self-cooled liquid-metal blanket concept

International Nuclear Information System (INIS)

Malang, S.; Arheidt, K.; Barleon, L.

1988-01-01

A blanket concept for the Next European Torus (NET) where 83Pb-17Li serves both as breeder material and as coolant is described. The concept is based on the use of novel flow channel inserts for a decisive reduction of the magnetohydrodynamic (MHD) pressure drop and employs beryllium as neutron multiplier in order to avoid the need for breeding blankets at the inboard side of the torus. This study includes the design, neutronics, thermal hydraulics, stresses, MHDs, corrosion, tritium recovery, and safety of a self-cooled liquid-metal blanket. The results of the investigations indicate that the self-cooled blanket is an attractive alternative to other driver blanket concepts for NET and that it can be extrapolated to the conditions of a DEMO reactor

Transjugular Intrahepatic Portosystemic Shunt Flow Reduction with Adjustable Polytetrafluoroethylene-Covered Balloon-Expandable Stents Using the “Sheath Control” Technique

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Blue, Robert C., E-mail: Robert.c.blue@gmail.com; Lo, Grace C.; Kim, Edward; Patel, Rahul S.; Scott Nowakowski, F.; Lookstein, Robert A.; Fischman, Aaron M. [Icahn School of Medicine at Mount Sinai, Interventional Radiology Section, Department of Radiology (United States)

2016-06-15

PurposeA complication of transjugular intrahepatic portosystemic shunts (TIPS) placement is refractory portosystemic encephalopathy (PSE) often requiring TIPS reduction. We report the results of a “sheath control technique” utilizing constraining sheaths during deployment of polytetrafluoroethylene (PTFE)-covered balloon-expandable stents, minimizing stent migration, and providing additional procedural control.MethodsTIPS reduction was performed in 10 consecutive patients for PSE using Atrium iCast covered stents (Atrium Maquet Getinge Group, Germany). Within the indwelling TIPS stent, a 9 mm × 59 mm iCast stent was deployed with 2 cm exposed from the sheath’s distal end and the majority of the stent within the sheath to create the distal hourglass shape. During balloon retraction, the stent was buttressed by the sheath. The proximal portion of the stent was angioplastied to complete the hourglass configuration, and the central portion of the stent was dilated to 5 mm. Demographics, pre- and post-procedure laboratory values, and outcomes were recorded.ResultsTen patients underwent TIPS reduction with 100 % technical success. There was no stent migration during stent deployment. All patients experienced initial improvement of encephalopathy. One patient ultimately required complete TIPS occlusion for refractory PSE, and another developed TIPS occlusion 36 days post-procedure. There was no significant trend toward change in patients’ MELD scores immediately post-procedure or at 30 days (p = 0.46, p = 0.47, respectively).ConclusionTIPS reduction using Atrium iCast PTFE balloon-expandable stents using the “sheath control technique” is safe and effective, and minimizes the risk of stent migration.

Successful management of a benign anastomotic colonic stricture with self-expanding metallic stents: A case report

Science.gov (United States)

Guan, Yong-Song; Sun, Long; Li, Xiao; Zheng, Xiao-Hua

2004-01-01

AIM: To assess the effectiveness of and complications associated with metallic stent placement for treatment of anastomotic colonic strictures. METHODS: A 46-year-old man underging two procedures of surgery for perforation of descending colon due to a traffic accident presented with pain, abdominal distention, and inability to defecate. Single-contrast barium enema radiograph showed a severe stenosis in the region of surgical anastomosis and the patient was too weak to accept another laparotomy. Under fluoroscopic and endoscopic guidance, we placed two metallic stents in the stenosis site of the anastomosis of the patient with anastomotic colonic strictures. RESULTS: In this case of postsurgical stenosis, the first stent relieved the symptoms of obstruction, but stent migration happened on the next day so an additional stent was required to deal with the stricture and relieve the symptoms. CONCLUSION: This case confirms that metallic stenting may represent an effective treatment for anastomotic colonic strictures in the absence of other therapeutic alternatives. PMID:15526381

Long-term results after carotid artery stenting. Restenosis after carotid artery stenting using self-expandable stent

International Nuclear Information System (INIS)

Matsumoto, Yasushi; Furui, Eisuke; Tsuboi, Ken; Takahashi, Akira; Ezura, Masayuki

2008-01-01

Carotid artery stenting has emerged as an acceptable treatment alternative in patients with carotid artery stenosis. Although early clinical results of carotid artery stenting have shown promise, long, term clinical results remain less certain. We report the frequency, management, and clinical results of in-stent restenosis after carotid artery stenting using a self-expandable stent. Between August 1998 and September 2004, 80 carotid artery stenting procedures in 78 patients were performed. We evaluated 76 of the 80 procedures in 75 of the 78 patients treated during this period who had a minimum 6-month clinical and imaging (ultrasound and/or magnetic resonance angiography) follow-up. Recurrent stenosis (≥50%) after carotid artery stenting occurred in 3 (3.9%) patients. The recurrent stenosis occurred within one year after the procedure in all cases. The low rate of in-stent restenosis using self-expandable stent suggested that carotid artery stenting may be an effective alternative treatment for carotid artery stenosis, but more data of long-term follow-up are required. (author)

Self-ligating versus conventional metallic brackets on Streptococcus mutans retention: A systematic review.

Science.gov (United States)

Longoni, Juliano N; Lopes, Beatriz M; Freires, Irlan A; Dutra, Kamile L; Franco, Ademir; Paranhos, Luiz R

2017-01-01

The present study aimed to review the literature systematically and assess comparatively whether self-ligating metallic brackets accumulate less Streptococcus mutans biofilm than conventional metallic brackets. The systematic search was performed following PRISMA guidelines and registration in PROSPERO. Seven electronic databases (Google Scholar, LILACS, Open Grey, PubMed, SciELO, ScienceDirect, and Scopus) were consulted until April 2016, with no restriction of language and time of publication. Only randomized clinical studies verifying S. mutans colonization in metallic brackets (self-ligating and conventional) were included. All steps were performed independently by two operators. The search resulted in 546 records obtained from the electronic databases. Additionally, 216 references obtained from the manual search of eligible articles were assessed. Finally, a total of 5 studies were included in the qualitative synthesis. In 1 study, the total bacterial count was not different among self-ligating and conventional brackets, whereas in 2 studies the amount was lower for self-ligating brackets. Regarding the specific count of S. mutans , 2 studies showed less accumulation in self-ligating than in conventional brackets. Based on the limited evidence, self-ligating metallic brackets accumulate less S. mutans than conventional ones. However, these findings must be interpreted in conjunction with particularities individual for each patient - such as hygiene and dietary habits, which are components of the multifactorial environment that enables S. Mutans to proliferate and keep retained in the oral cavity.

Electrokinetic remediation of heavy metals contaminated kaolin by a CNT-covered polyethylene terephthalate yarn cathode

International Nuclear Information System (INIS)

Yuan, Lizhu; Li, Haiyan; Xu, Xingjian; Zhang, Jing; Wang, Nana; Yu, Hongwen

2016-01-01

In the current study, carbon nanotube (CNT) covered polyethylene terephthalate yarns (PET-CNT) electrode has been investigated as a novel cathode material for the electrokinetic (EK) remediation of multi-metals (Cd, Cu, Ni, Pb, Zn) contaminated kaolin. The results of scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) showed that CNT was successfully covered on the surface of PET. The results obtained from EK process showed that PET-CNT as a cathode obviously elevated electric current and electro-osmotic flow (EOF), significantly decreased kaolin pH, and enhanced heavy metals removal efficiencies. The removal efficiencies of Cd, Cu, Ni, Pb, and Zn in PET-CNT treatment were 89.7%, 63.6%, 90.7%, 19.2%, and 88.7%, respectively. In comparison with the Pt/Ti and graphite treatments, the removal efficiencies of Cd, Ni, and Zn were improved at least about 30%, Cu and Pb were improved at least 16.6% and 6.9%, respectively. Our results demonstrated the PET-CNT was a good alternative cathode material for enhancing efficiency of EK remediation.

Tratamiento paliativo de la obstrucción tumoral del vaciamiento gástrico con prótesis metálicas autoexpandibles insertadas endoscópicamente Palliative management of malignant gastric outlet obstruction with endoscopically inserted self-expanding metal stents

Directory of Open Access Journals (Sweden)

J. García-Cano

2008-06-01

Spanish National Health System. Patients and methods: a retrospective five-year study (2003-2007 was conducted in 23 patients who underwent 27 procedures aimed at resolving malignant gastric outlet obstruction (mean, 0.45 procedures per month using endoscopically inserted noncovered stents (Wallstent® and Wallflex®. Results: insertion was technically feasible in all 27 (100% attempts, with satisfactory clinical results in 25 cases (92.5%. Endoscopy alone was used 10 times (37%, and both endoscopy and fluoroscopy on 17 (63% occasions. After stent insertion, one patient was intervened for treatment, and a patient with an unsuccessful prosthesis received a palliative surgical bypass. Four stents became obstructed by tumoral ingrowth, and patency was reestablished by inserting a new stent. Obstructive jaundice caused by stents covering the papilla of Vater occurred in three cases. There were no other complications or mortality due to the procedure. Mean survival was 104 days (range 28-400, SD ± 94. Conclusions: In our experience endoscopic insertion of self-expanding metal stents appears to be a safe and efficient palliative method for malignant gastric outlet obstruction, and can be performed successfully in a center with our characteristics.

In-vitro interactions of human chondrocytes and mesenchymal stem cells, and of mouse macrophages with phospholipid-covered metallic implant materials

Directory of Open Access Journals (Sweden)

R Willumeit

2007-03-01

Full Text Available Phospholipid-coatings on metallic implant surfaces were evaluated in terms of adhesion, proliferation and matrix production of skeletal cells, and of macrophage stimulation. The working hypothesis is that mimicking a model biomembrane by phospholipids on surfaces to which cells adhere, the surface recognition by surrounding cells is altered. In this study, 1 mirror-like polished Ti-6Al-7Nb and 2 porous Ti-6Al-4V specimens were covered with the phospholipids POPE (palmitoyl-oleoyl phosphatidyl-ethanolamine and POPC (palmitoyl-oleoyl phosphatidyl-choline, and the interactions of a human articular chondrocytes (HAC, b human mesenchymal stem cells (HMSC, and c mouse macrophages (RAW 264.7 were tested in vitro. On POPE-covered polished surfaces adherence of HAC (42% of seeded cells after 2 hrs and metabolic activity (MTT after 3 days were reduced, while on porous surfaces 99% HAC adhered, and metabolic activity was significantly increased, compared to respective native surfaces. On both POPE-covered surfaces the chondrocyte phenotype was present. After 3 weeks of chondrogenic differentiation, cartilage matrix production (measuring chondroitin sulphate per HAC number was significantly increased by about 30% on both POPE-covered metallic surfaces. On both POPC-covered surfaces nearly no adhering and surviving HAC were found. HMSC grown on POPE-covered porous substrates showed osteogenic differentiation by improved osteopontin and collagen I expression in RT-PCR, and osteocalcin fluorescence and bone nodule formation was only detectable on POPE-covered porous surfaces. In contrast to POPC and other phospholipids used as positive controls, POPE did not stimulate the NO production in mouse macrophage cultures. We therefore conclude that a phospholipid coating by POPE shows potential as surface modification for metallic implant materials.

Performances of an expanding insect under elevated CO{sub 2} and snow cover in the Alps

Energy Technology Data Exchange (ETDEWEB)

Battisti, B.; Petrucco-Toffolo, E. [University of Padova, Legnaro (Italy). Dept. of Environmental Agronomy

2008-09-30

Variations of phenology and distribution have been recently highlighted in numerous insect species and attributed to climate change, particularly the increase of temperature and atmospheric carbon dioxide (CO{sub 2}). Both have been shown to have direct and indirect effects on insect species of various ecosystems, though the responses are often species-specific. The pine processionary moth, Thaumetopoea pityocampa (Lepidoptera, Notodontidae) is an important pest of conifers in the Mediterranean region, and has been recently shown to expand its altitudinal range in the Alps, including the mountain pine Pinus mugo as a novel host. We had the opportunity to transplant colonies of the pine processionary moth to a high elevation site well outside of the current range of the insect (Stillberg, Davos, Switzerland, 2180 m), where trees of the mountain pine have been grown for five years under ambient and elevated CO{sub 2} concentrations (ca. 570 ppm). The aim of the study was to evaluate the response of first instar larvae to extreme conditions of temperature and to an altered performance induced by the change of host metabolism under elevated CO{sub 2}. Larval mortality and relative growth rate did not differ between host trees grown in ambient or elevated CO{sub 2}. As extended snow cover may be an important mortality factor of larval colonies on the dwarf trees of mountain pine, we tested the survival of colonies transplanted at two extreme sites of Eastern Alps. The snow cover extended over more than one month proved to be an important mortality factor of larval colonies on mountain pine. We concluded that the first instar larvae of the pine processionary moth are not concerned by unusually low temperature and CO{sub 2} increase whereas they can be later strongly affected by snow accumulation. The decrease of snow cover observed in the last decades, however, may reduce such a risk.

[The implantation of elastic metal endoprostheses in tracheal stenosis and tracheomalacia. The initial results with 4 patients].