Cost effectiveness of mesh prophylaxis to prevent parastomal hernia in patients undergoing permanent colostomy for rectal cancer.

Science.gov (United States)

Lee, Lawrence; Saleem, Abdulaziz; Landry, Tara; Latimer, Eric; Chaudhury, Prosanto; Feldman, Liane S

2014-01-01

Parastomal hernia (PSH) is common after stoma formation. Studies have reported that mesh prophylaxis reduces PSH, but there are no cost-effectiveness data. Our objective was to determine the cost effectiveness of mesh prophylaxis vs no prophylaxis to prevent PSH in patients undergoing abdominoperineal resection with permanent colostomy for rectal cancer. Using a cohort Markov model, we modeled the costs and effectiveness of mesh prophylaxis vs no prophylaxis at the index operation in a cohort of 60-year-old patients undergoing abdominoperineal resection for rectal cancer during a time horizon of 5 years. Costs were expressed in 2012 Canadian dollars (CAD$) and effectiveness in quality-adjusted life years. Deterministic and probabilistic sensitivity analyses were performed. In patients with stage I to III rectal cancer, prophylactic mesh was dominant (less costly and more effective) compared with no mesh. In patients with stage IV disease, mesh prophylaxis was associated with higher cost (CAD$495 more) and minimally increased effectiveness (0.05 additional quality-adjusted life years), resulting in an incremental cost-effectiveness ratio of CAD$10,818 per quality-adjusted life year. On sensitivity analyses, the decision was sensitive to the probability of mesh infection and the cost of the mesh, and method of diagnosing PSH. In patients undergoing abdominoperineal resection with permanent colostomy for rectal cancer, mesh prophylaxis might be the less costly and more effective strategy compared with no mesh to prevent PSH in patients with stage I to III disease, and might be cost effective in patients with stage IV disease. Copyright © 2014 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Mesh versus non-mesh repair of ventral abdominal hernias

International Nuclear Information System (INIS)

Jawaid, M.A.; Talpur, A.H.

2008-01-01

To investigate the relative effectiveness of mesh and suture repair of ventral abdominal hernias in terms of clinical outcome, quality of life and rate of recurrence in both the techniques. This is a retrospective descriptive analysis of 236 patients with mesh and non-mesh repair of primary ventral hernias performed between January 2000 to December 2004 at Surgery Department, Liaquat University of Medical and Health Sciences, Jamshoro. The record sheets of the patients were analyzed and data retrieved to compare the results of both techniques for short-term and long-term results. The data retrieved is statistically analyzed on SPSS version 11. There were 43 (18.22%) males and 193 (81.77%) females with a mean age of 51.79 years and a range of 59 (81-22). Para-umbilical hernia was the commonest of ventral hernia and accounted for 49.8% (n=118) of the total study population followed by incisional hernia comprising 24% (n=57) of the total number. There was a significant difference in the recurrent rate at 3 years interval with 23/101 (22.77%) recurrences in suture-repaired subjects compared to 10/135 (7.40%) in mesh repair group. Chronic pain lasting up to 1-2 years was noted in 14 patients with suture repair. Wound infection is comparatively more common (8.14%) in mesh group. The other variables such as operative and postoperative complications, total hospital stay and quality of life is also discussed. Mesh repair of ventral hernia is much superior to non-mesh suture repair in terms of recurrence and overall outcome. (author)

To mesh or not to mesh: a review of pelvic organ reconstructive surgery

Science.gov (United States)

Dällenbach, Patrick

2015-01-01

Pelvic organ prolapse (POP) is a major health issue with a lifetime risk of undergoing at least one surgical intervention estimated at close to 10%. In the 1990s, the risk of reoperation after primary standard vaginal procedure was estimated to be as high as 30% to 50%. In order to reduce the risk of relapse, gynecological surgeons started to use mesh implants in pelvic organ reconstructive surgery with the emergence of new complications. Recent studies have nevertheless shown that the risk of POP recurrence requiring reoperation is lower than previously estimated, being closer to 10% rather than 30%. The development of mesh surgery – actively promoted by the marketing industry – was tremendous during the past decade, and preceded any studies supporting its benefit for our patients. Randomized trials comparing the use of mesh to native tissue repair in POP surgery have now shown better anatomical but similar functional outcomes, and meshes are associated with more complications, in particular for transvaginal mesh implants. POP is not a life-threatening condition, but a functional problem that impairs quality of life for women. The old adage “primum non nocere” is particularly appropriate when dealing with this condition which requires no treatment when asymptomatic. It is currently admitted that a certain degree of POP is physiological with aging when situated above the landmark of the hymen. Treatment should be individualized and the use of mesh needs to be selective and appropriate. Mesh implants are probably an important tool in pelvic reconstructive surgery, but the ideal implant has yet to be found. The indications for its use still require caution and discernment. This review explores the reasons behind the introduction of mesh augmentation in POP surgery, and aims to clarify the risks, benefits, and the recognized indications for its use. PMID:25848324

Understanding and predicting size selection in diamond-mesh cod ends for danish seining: A study based on sea trials and computer simulations

DEFF Research Database (Denmark)

Herrmann, Bent; Krag, Ludvig Ahm; Feekings, Jordan P.

2016-01-01

described by a double logistic selection curve, implying that two different size selection processes occur in the cod end. The double selection process could be explained by an additional selection process occurring through slack meshes. The results imply that the escapement of 46% and 34% of the larger...... Atlantic Cod and Haddock (those above 48 cm), respectively, would be through wide-open or slack meshes. Since these mesh states are only likely to be present in the latest stage of the fishing process (e.g., when the cod end is near the surface), a large fraction of the bigger fish probably escaped near...

Positive Contrast MRI Techniques for Visualization of Iron-Loaded Hernia Mesh Implants in Patients.

Directory of Open Access Journals (Sweden)

Alexander Ciritsis

Full Text Available In MRI, implants and devices can be delineated via susceptibility artefacts. To discriminate susceptibility voids from proton-free structures, different positive contrast techniques were implemented. The purpose of this study was to evaluate a pulse sequence-based positive contrast technique (PCSI and a post-processing susceptibility gradient mapping algorithm (SGM for visualization of iron loaded mesh implants in patients.Five patients with iron-loaded MR-visible inguinal hernia mesh implants were examined at 1.5 Tesla. A gradient echo sequence (GRE; parameters: TR: 8.3ms; TE: 4.3ms; NSA:2; FA:20°; FOV:350mm² and a PCSI sequence (parameters: TR: 25ms; TE: 4.6ms; NSA:4; FA:20°; FOV:350mm² with on-resonant proton suppression were performed. SGM maps were calculated using two algorithms. Image quality and mesh delineation were independently evaluated by three radiologists.On GRE, the iron-loaded meshes generated distinct susceptibility-induced signal voids. PCSI exhibited susceptibility differences including the meshes as hyperintense signals. SGM exhibited susceptibility differences with positive contrast. Visually, the different algorithms presented no significant differences. Overall, the diagnostic value was rated best in GRE whereas PCSI and SGM were barely "sufficient".Both "positive contrast" techniques depicted implanted meshes with hyperintense signal. SGM comes without additional acquisition time and can therefore be utilized in every patient.

Mesh Excision: Is Total Mesh Excision Necessary?

Science.gov (United States)

Wolff, Gillian F; Winters, J Christian; Krlin, Ryan M

2016-04-01

Nearly 29% of women will undergo a secondary, repeat operation for pelvic organ prolapse (POP) symptom recurrence following a primary repair, as reported by Abbott et al. (Am J Obstet Gynecol 210:163.e1-163.e1, 2014). In efforts to decrease the rates of failure, graft materials have been utilized to augment transvaginal repairs. Following the success of using polypropylene mesh (PPM) for stress urinary incontinence (SUI), the use of PPM in the transvaginal repair of POP increased. However, in recent years, significant concerns have been raised about the safety of PPM mesh. Complications, some specific to mesh, such as exposures, erosion, dyspareunia, and pelvic pain, have been reported with increased frequency. In the current literature, there is not substantive evidence to suggest that PPM has intrinsic properties that warrant total mesh removal in the absence of complications. There are a number of complications that can occur after transvaginal mesh placement that do warrant surgical intervention after failure of conservative therapy. In aggregate, there are no high-quality controlled studies that clearly demonstrate that total mesh removal is consistently more likely to achieve pain reduction. In the cases of obstruction and erosion, it seems clear that definitive removal of the offending mesh is associated with resolution of symptoms in the majority of cases and reasonable practice. There are a number of complications that can occur with removal of mesh, and patients should be informed of this as they formulate a choice of treatment. We will review these considerations as we examine the clinical question of whether total versus partial removal of mesh is necessary for the resolution of complications following transvaginal mesh placement.

Energy-aware path selection metric for IEEE 802.11s wireless mesh networking

CSIR Research Space (South Africa)

Mhlanga, MM

2009-01-01

Full Text Available The IEEE 802.11s working group has commenced activities, which would lead to the development of a standard for wireless mesh networks (WMNs). The draft of 802.11s introduces a new path selection metric called airtime link metric. However...

Energy-aware path selection metric for IEEE 802.11s wireless mesh networking

CSIR Research Space (South Africa)

Mhlanga, MM

2009-08-01

Full Text Available The IEEE 802.11s working group has commenced activities, which would lead to the development of a standard for wireless mesh networks (WMNs). The draft of 802.11s introduces a new path selection metric called airtime link metric. However...

To mesh or not to mesh: a review of pelvic organ reconstructive surgery

Directory of Open Access Journals (Sweden)

Dällenbach P

2015-04-01

Full Text Available Patrick Dällenbach Department of Gynecology and Obstetrics, Division of Gynecology, Urogynecology Unit, Geneva University Hospitals, Geneva, Switzerland Abstract: Pelvic organ prolapse (POP is a major health issue with a lifetime risk of undergoing at least one surgical intervention estimated at close to 10%. In the 1990s, the risk of reoperation after primary standard vaginal procedure was estimated to be as high as 30% to 50%. In order to reduce the risk of relapse, gynecological surgeons started to use mesh implants in pelvic organ reconstructive surgery with the emergence of new complications. Recent studies have nevertheless shown that the risk of POP recurrence requiring reoperation is lower than previously estimated, being closer to 10% rather than 30%. The development of mesh surgery – actively promoted by the marketing industry – was tremendous during the past decade, and preceded any studies supporting its benefit for our patients. Randomized trials comparing the use of mesh to native tissue repair in POP surgery have now shown better anatomical but similar functional outcomes, and meshes are associated with more complications, in particular for transvaginal mesh implants. POP is not a life-threatening condition, but a functional problem that impairs quality of life for women. The old adage “primum non nocere” is particularly appropriate when dealing with this condition which requires no treatment when asymptomatic. It is currently admitted that a certain degree of POP is physiological with aging when situated above the landmark of the hymen. Treatment should be individualized and the use of mesh needs to be selective and appropriate. Mesh implants are probably an important tool in pelvic reconstructive surgery, but the ideal implant has yet to be found. The indications for its use still require caution and discernment. This review explores the reasons behind the introduction of mesh augmentation in POP surgery, and aims to

Management of complications of mesh surgery.

Science.gov (United States)

Lee, Dominic; Zimmern, Philippe E

2015-07-01

Transvaginal placements of synthetic mid-urethral slings and vaginal meshes have largely superseded traditional tissue repairs in the current era because of presumed efficacy and ease of implant with device 'kits'. The use of synthetic material has generated novel complications including mesh extrusion, pelvic and vaginal pain and mesh contraction. In this review, our aim is to discuss the management, surgical techniques and outcomes associated with mesh removal. Recent publications have seen an increase in presentation of these mesh-related complications, and reports from multiple tertiary centers have suggested that not all patients benefit from surgical intervention. Although the true incidence of mesh complications is unknown, recent publications can serve to guide physicians and inform patients of the surgical outcomes from mesh-related complications. In addition, the literature highlights the growing need for a registry to account for a more accurate reporting of these events and to counsel patients on the risk and benefits before proceeding with mesh surgeries.

Mesh size in Lichtenstein repair: a systematic review and meta-analysis to determine the importance of mesh size.

Science.gov (United States)

Seker, D; Oztuna, D; Kulacoglu, H; Genc, Y; Akcil, M

2013-04-01

Small mesh size has been recognized as one of the factors responsible for recurrence after Lichtenstein hernia repair due to insufficient coverage or mesh shrinkage. The Lichtenstein Hernia Institute recommends a 7 × 15 cm mesh that can be trimmed up to 2 cm from the lateral side. We performed a systematic review to determine surgeons' mesh size preference for the Lichtenstein hernia repair and made a meta-analysis to determine the effect of mesh size, mesh type, and length of follow-up time on recurrence. Two medical databases, PubMed and ISI Web of Science, were systematically searched using the key word "Lichtenstein repair." All full text papers were selected. Publications mentioning mesh size were brought for further analysis. A mesh surface area of 90 cm(2) was accepted as the threshold for defining the mesh as small or large. Also, a subgroup analysis for recurrence pooled proportion according to the mesh size, mesh type, and follow-up period was done. In total, 514 papers were obtained. There were no prospective or retrospective clinical studies comparing mesh size and clinical outcome. A total of 141 papers were duplicated in both databases. As a result, 373 papers were obtained. The full text was available in over 95 % of papers. Only 41 (11.2 %) papers discussed mesh size. In 29 studies, a mesh larger than 90 cm(2) was used. The most frequently preferred commercial mesh size was 7.5 × 15 cm. No papers mentioned the size of the mesh after trimming. There was no information about the relationship between mesh size and patient BMI. The pooled proportion in recurrence for small meshes was 0.0019 (95 % confidence interval: 0.007-0.0036), favoring large meshes to decrease the chance of recurrence. Recurrence becomes more marked when follow-up period is longer than 1 year (p < 0.001). Heavy meshes also decreased recurrence (p = 0.015). This systematic review demonstrates that the size of the mesh used in Lichtenstein hernia repair is rarely

Performance of the hybrid wireless mesh protocol for wireless mesh networks

DEFF Research Database (Denmark)

Boye, Magnus; Staalhagen, Lars

2010-01-01

Wireless mesh networks offer a new way of providing end-user access and deploying network infrastructure. Though mesh networks offer a price competitive solution to wired networks, they also come with a set of new challenges such as optimal path selection, channel utilization, and load balancing....... and proactive. Two scenarios of different node density are considered for both path selection modes. The results presented in this paper are based on a simulation model of the HWMP specification in the IEEE 802.11s draft 4.0 implemented in OPNET Modeler....

Functional cine MRI of the abdomen for the assessment of implanted synthetic mesh in patients after incisional hernia repair: initial results

Energy Technology Data Exchange (ETDEWEB)

Fischer, Tanja [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany); Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Klinikum Innenstadt, Munich (Germany); Ladurner, Roland; Mussack, Thomas [Ludwig-Maximilians-University Munich, Department of Surgery and Traumatology, Klinikum Innenstadt, Munich (Germany); Gangkofer, Alexander; Reiser, Maximilian; Lienemann, Andreas [Ludwig-Maximilians-University Munich, Department of Clinical Radiology, Munich (Germany)

2007-12-15

The aim of our study was to develop a method that allows the vizualiation and evaluation of implanted mesh in patients after incisional hernia repair with MRI. Furthermore, we assessed problems typically related with mesh implantation like adhesions and muscular atrophy. We enrolled 28 patients after incisional hernia repair. In 10 patients mesh implantation was done by laparoscopy (expanded polytetrafluoroethylene=ePTFE mesh) and in 18 by laparotomy (polypropylene mesh). Functional MRI was performed on a 1.5-T system in supine position. Sagittal and axial TrueFISP images of the entire abdomen were acquired with the patient repeatedly straining. Evaluation included: correct position and intact fixation of the mesh, furthermore visceral adhesions, recurrent hernia and atrophy of the rectus muscle. The ePTFE mesh was visible in all cases; the polypropylene mesh was not detectable. In seven of the ten ePTFE meshes the fixation was not intact; two recurrent hernias were detected. Twenty of 28 patients had intraabdominal adhesions. In 5 cases mobility of the abdominal wall was reduced, and 16 patients showed an atropy of the rectus muscle. Functional cine MRI is a suitable method for follow-up studies in patients after hernia repair. ePTFE meshes can be visualized directly, and typical complications like intestinal adhesions and abdominal wall dysmotility can be assessed reliably. (orig.)

Selective separation of oil and water with special wettability mesh membranes

KAUST Repository

Liu, Defei

2017-02-24

Due to the different interfacial effects of oil and water, utilizing the special wettability of solid surfaces to design an oil and water separation process has been demonstrated to be an effective approach for oil/water separation. In this report, a simple process has been developed to fabricate special surface wettability mesh membranes. The carbon nanoparticles with diameters of 10 nm were first coated onto the surface of steel wires based on a candle soot coating process. These templates of carbon nanoparticles were then coated with a more stable layer of silica (SiO2) particles via a facile chemical vapor deposition route. After being modified by two separate methods, a superhydrophobic/superoleophilic membrane was obtained by the use of 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) and a oleophobic/superhydrophilic membrane was obtained by using poly(diallyldimethylammonium-perfluorooctanoate) (PDDA–PFO). Separation experiments show that these superhydrophobic/superoleophilic or oleophobic/superhydrophilic mesh membranes can be used to selectively separate oil/water with a high flux of more than 930 L m−2 h−1 and a collecting efficiency of over 97%. Furthermore, the repetitions of the separation experiments demonstrate that these superhydrophobic/superoleophilic or oleophobic/superhydrophilic mesh membranes are durable, stable and reusable, making them encouraging candidates for practical oil-polluted water treatment.

Effect of netting direction and number of meshes around on size selection in the codend for Baltic cod (Gadus morhua)

DEFF Research Database (Denmark)

Wienbeck, Harald; Herrmann, Bent; Moderhak, Waldemar

2011-01-01

We investigated experimentally the effect that turning the netting direction 90° (T90) and halving the number of meshes around in the circumference in a diamond mesh codend had on size selection of Baltic cod. The results generally agreed with predictions of a previous simulation-based study. Both...... modifications had a significant positive effect on the size selection of cod. The best selection results were obtained for a codend in which both factors were applied together. For that codend, very little between-haul variation in cod size selection was detected, especially compared to the reference codend...

An eFTD-VP framework for efficiently generating patient-specific anatomically detailed facial soft tissue FE mesh for craniomaxillofacial surgery simulation.

Science.gov (United States)

Zhang, Xiaoyan; Kim, Daeseung; Shen, Shunyao; Yuan, Peng; Liu, Siting; Tang, Zhen; Zhang, Guangming; Zhou, Xiaobo; Gateno, Jaime; Liebschner, Michael A K; Xia, James J

2018-04-01

Accurate surgical planning and prediction of craniomaxillofacial surgery outcome requires simulation of soft tissue changes following osteotomy. This can only be achieved by using an anatomically detailed facial soft tissue model. The current state-of-the-art of model generation is not appropriate to clinical applications due to the time-intensive nature of manual segmentation and volumetric mesh generation. The conventional patient-specific finite element (FE) mesh generation methods are to deform a template FE mesh to match the shape of a patient based on registration. However, these methods commonly produce element distortion. Additionally, the mesh density for patients depends on that of the template model. It could not be adjusted to conduct mesh density sensitivity analysis. In this study, we propose a new framework of patient-specific facial soft tissue FE mesh generation. The goal of the developed method is to efficiently generate a high-quality patient-specific hexahedral FE mesh with adjustable mesh density while preserving the accuracy in anatomical structure correspondence. Our FE mesh is generated by eFace template deformation followed by volumetric parametrization. First, the patient-specific anatomically detailed facial soft tissue model (including skin, mucosa, and muscles) is generated by deforming an eFace template model. The adaptation of the eFace template model is achieved by using a hybrid landmark-based morphing and dense surface fitting approach followed by a thin-plate spline interpolation. Then, high-quality hexahedral mesh is constructed by using volumetric parameterization. The user can control the resolution of hexahedron mesh to best reflect clinicians' need. Our approach was validated using 30 patient models and 4 visible human datasets. The generated patient-specific FE mesh showed high surface matching accuracy, element quality, and internal structure matching accuracy. They can be directly and effectively used for clinical

An Approach for Patient-Specific Multi-domain Vascular Mesh Generation Featuring Spatially Varying Wall Thickness Modeling

OpenAIRE

Raut, Samarth S.; Liu, Peng; Finol, Ender A.

2015-01-01

In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent ...

Prolapse Recurrence after Transvaginal Mesh Removal.

Science.gov (United States)

Rawlings, Tanner; Lavelle, Rebecca S; Coskun, Burhan; Alhalabi, Feras; Zimmern, Philippe E

2015-11-01

We determined the rate of pelvic organ prolapse recurrence after transvaginal mesh removal. Following institutional review board approval a longitudinally collected database of women undergoing transvaginal mesh removal for complications after transvaginal mesh placement with at least 1 year minimum followup was queried for pelvic organ prolapse recurrence. Recurrent prolapse was defined as greater than stage 1 on examination or the need for reoperation at the site of transvaginal mesh removal. Outcome measures were based on POP-Q (Pelvic Organ Prolapse Quantification System) at the last visit. Patients were grouped into 3 groups, including group 1--recurrent prolapse in the same compartment as transvaginal mesh removal, 2--persistent prolapse and 3--prolapse in a compartment different than transvaginal mesh removal. Of 73 women 52 met study inclusion criteria from 2007 to 2013, including 73% who presented with multiple indications for transvaginal mesh removal. The mean interval between insertion and removal was 45 months (range 10 to 165). Overall mean followup after transvaginal mesh removal was 30 months (range 12 to 84). In group 1 (recurrent prolapse) the rate was 15% (6 of 40 patients). Four women underwent surgery for recurrent prolapse at a mean 7 of months (range 5 to 10). Two patients elected observation. The rate of persistent prolapse (group 2) was 23% (12 of 52 patients). Three women underwent prolapse reoperation at a mean of 10 months (range 8 to 12). In group 3 (de novo/different compartment prolapse) the rate was 6% (3 of 52 patients). One woman underwent surgical repair at 52 months. At a mean 2.5-year followup 62% of patients (32 of 52) did not have recurrent or persistent prolapse after transvaginal mesh removal and 85% (44 of 52) did not undergo any further procedure for prolapse. Specifically for pelvic organ prolapse in the same compartment as transvaginal mesh removal 12% of patients had recurrence, of whom 8% underwent prolapse repair

Postoperative pain outcomes after transvaginal mesh revision.

Science.gov (United States)

Danford, Jill M; Osborn, David J; Reynolds, W Stuart; Biller, Daniel H; Dmochowski, Roger R

2015-01-01

Although the current literature discusses mesh complications including pain, as well as suggesting different techniques for removing mesh, there is little literature regarding pain outcomes after surgical removal or revision. The purpose of this study is to determine if surgical removal or revision of vaginal mesh improves patient's subjective complaints of pelvic pain associated with original placement of mesh. After obtaining approval from the Vanderbilt University Medical Center Institutional Review Board, a retrospective review of female patients with pain secondary to previous mesh placement who underwent excision or revision of vaginal mesh from January 2000 to August 2012 was performed. Patient age, relevant medical history including menopause status, previous hysterectomy, smoking status, and presence of diabetes, fibromyalgia, interstitial cystitis, and chronic pelvic pain, was obtained. Patients' postoperative pain complaints were assessed. Of the 481 patients who underwent surgery for mesh revision, removal or urethrolysis, 233 patients met our inclusion criteria. One hundred and sixty-nine patients (73 %) reported that their pain improved, 19 (8 %) reported that their pain worsened, and 45 (19 %) reported that their pain remained unchanged after surgery. Prior history of chronic pelvic pain was associated with increased risk of failure of the procedure to relieve pain (OR 0.28, 95 % CI 0.12-0.64, p = 0.003). Excision or revision of vaginal mesh appears to be effective in improving patients' pain symptoms most of the time. Patients with a history of chronic pelvic pain are at an increased risk of no improvement or of worsening pain.

Reengineering of MeSH thesauri for term selection to optimize literature retrieval and knowledge reconstruction in support of stem cell research.

Science.gov (United States)

Su, Yan; Andrews, James; Huang, Hong; Wang, Yue; Kong, Liangliang; Cannon, Peter; Xu, Ping

2016-05-23

PubMed is a widely used database for scientists to find biomedical-related literature. Due to the complexity of the selected research subject and its interdisciplinary nature, as well as the exponential growth in the number of disparate pieces of biomedical literature, it is an overwhelming challenge for scientists to define the right search strategies and quickly locate all related information. Specialized subsets and groupings of controlled vocabularies, such as Medical Subject Headings (MeSH), can enhance information retrieval in specialized domains, such as stem cell research. There is a need to develop effective search strategies and convenient solutions for knowledge organization in stem cell research. The understanding of the interrelationships between these MeSH terms also facilitates the building of knowledge organization systems in related subject fields. This study collected empirical data for MeSH-related terms from stem cell literature and developed a novel approach that uses both automation and expert-selection to create a set of terms that supports enhanced retrieval. The selected MeSH terms were reconstructed into a classified thesaurus that can guide researchers towards a successful search and knowledge organization of stem cell literature. First, 4253 MeSH terms were harvested from a sample of 5527 stem cell related research papers from the PubMed database. Next, unrelated terms were filtered out based on term frequency and specificity. Precision and recall measures were used to help identify additional valuable terms, which were mostly non-MeSH terms. The study identified 15 terms that specifically referred to stem cell research for information retrieval, which would yield a higher precision (97.7 %) and recall (94.4 %) rates in comparison to other approaches. In addition, 128 root MeSH terms were selected to conduct knowledge organization of stem cell research in categories of anatomy, disease, and others. This study presented a novel strategy

Surgical intervention after transvaginal Prolift mesh repair: retrospective single-center study including 524 patients with 3 years' median follow-up.

Science.gov (United States)

de Landsheere, Laurent; Ismail, Sharif; Lucot, Jean-Philippe; Deken, Valérie; Foidart, Jean-Michel; Cosson, Michel

2012-01-01

The aim of this study was to explore the nature and rate of surgical intervention after transvaginal Prolift mesh repair for pelvic organ prolapse. This was a retrospective study of all patients who underwent Prolift mesh repair between January 2005 and January 2009. Patient data were obtained from medical records, and patients were telephoned to check if they had surgery in other hospitals. A total of 600 consecutive patients were identified. Of these, 524 patients (87.3%) were included in the study, with a median follow-up duration of 38 months (range, 15-63). Global reoperation rate was 11.6%. Indications of intervention were surgery for urinary incontinence (6.9%), mesh-related complications (3.6%), or prolapse recurrence (3%). The global reoperation rate after transvaginal Prolift mesh repair was 11.6%, with urinary incontinence surgery being the most common indication. Rates of mesh complications and prolapse recurrence are relatively low in an experienced team. Copyright © 2012 Mosby, Inc. All rights reserved.

Ventral hernia repair with poly-4-hydroxybutyrate mesh.

Science.gov (United States)

Plymale, Margaret A; Davenport, Daniel L; Dugan, Adam; Zachem, Amanda; Roth, John Scott

2018-04-01

Biomaterial research has made available a biologically derived fully resorbable poly-4-hydroxybutyrate (P4HB) mesh for use in ventral and incisional hernia repair (VIHR). This study evaluates outcomes of patients undergoing VIHR with P4HB mesh. An IRB-approved prospective pilot study was conducted to assess clinical and quality of life (QOL) outcomes for patients undergoing VIHR with P4HB mesh. Perioperative characteristics were defined. Clinical outcomes, employment status, QOL using 12-item short form survey (SF-12), and pain assessments were followed for 24 months postoperatively. 31 patients underwent VIHR with bioresorbable mesh via a Rives-Stoppa approach with retrorectus mesh placement. The median patient age was 52 years, median body mass index was 33 kg/m 2 , and just over half of the patients were female. Surgical site occurrences occurred in 19% of patients, most of which were seroma. Hernia recurrence rate was 0% (median follow-up = 414 days). Patients had significantly improved QOL at 24 months compared to baseline for SF-12 physical component summary and role emotional (p < 0.05). Ventral hernia repair with P4HB bioresorbable mesh results in favorable outcomes. Early hernia recurrence was not identified among the patient cohort. Quality of life improvements were noted at 24 months versus baseline for this cohort of patients with bioresorbable mesh. Use of P4HB mesh for ventral hernia repair was found to be feasible in this patient population. (ClinicalTrials.gov Identifier: NCT01863030).

A Tissue Relevance and Meshing Method for Computing Patient-Specific Anatomical Models in Endoscopic Sinus Surgery Simulation

Science.gov (United States)

Audette, M. A.; Hertel, I.; Burgert, O.; Strauss, G.

This paper presents on-going work on a method for determining which subvolumes of a patient-specific tissue map, extracted from CT data of the head, are relevant to simulating endoscopic sinus surgery of that individual, and for decomposing these relevant tissues into triangles and tetrahedra whose mesh size is well controlled. The overall goal is to limit the complexity of the real-time biomechanical interaction while ensuring the clinical relevance of the simulation. Relevant tissues are determined as the union of the pathology present in the patient, of critical tissues deemed to be near the intended surgical path or pathology, and of bone and soft tissue near the intended path, pathology or critical tissues. The processing of tissues, prior to meshing, is based on the Fast Marching method applied under various guises, in a conditional manner that is related to tissue classes. The meshing is based on an adaptation of a meshing method of ours, which combines the Marching Tetrahedra method and the discrete Simplex mesh surface model to produce a topologically faithful surface mesh with well controlled edge and face size as a first stage, and Almost-regular Tetrahedralization of the same prescribed mesh size as a last stage.

Clinical use of AO three-dimensionally preformed titanium mesh plates for orbital fractures

Directory of Open Access Journals (Sweden)

Ming Chen

2015-01-01

Full Text Available AIM:To evaluate the accuracy and practicability of three-dimensionally preformed Arbeitsgemeinschaft Osteosynthese AO titanium mesh plates for orbital fractures.METHODS:Forty-seven patients with isolated blow-out orbital fractures were included in this study. Fracture locations were as follows: floor/medial wall(n=26, 55%, medial wall(n=12, 26%, and floor(n=9, 19%. The floor fractures were exposed by a standard transconjunctival approach, whereas a combined transcaruncular transconjunctival approach was used in patients with medial wall fractures with temporary dissection of inferior oblique muscle. A three-dimensionally preformed AO titanium mesh plate was selected according to the size of the defect previously measured on the preoperative computed tomographic scan examination and fixed at the inferior orbital rim with 2 screws. The accuracy of plate positioning of the reconstructed orbit was assessed on the postoperative computed tomography(CTscan. The practicability of clinical use of AO three-dimensionally preformed titanium mesh plates was assessed on the preoperative and postoperative clinical data.RESULTS: Postoperative orbital CT scan showed an anatomic three-dimensional placement of the orbital mesh plates in all of the patients. All patients had a successful treatment outcome without clinical complications. 40 patients(87%had a successful enophthalmos correction. 25 patients(86%had a successful recovery from diplopia.CONCLUSION: Three-dimensionally preformed AO titanium mesh plates for orbital fracture reconstruction results in an accurate anatomic restoration of the bony orbital contour with a high rate of success to correctenophthalmos and diplopia.

[CLINICAL EVALUATION OF THE NEW ANTISEPTIC MESHES].

Science.gov (United States)

Gogoladze, M; Kiladze, M; Chkhikvadze, T; Jiqia, D

2016-12-01

Improving the results of hernia treatment and prevention of complications became a goal of our research which included two parts - experimental and clinical. Histomorphological and bacteriological researches showed that the best result out of the 3 control groups was received in case of covering implant "Coladerm"+ with chlorhexidine. Based on the experiment results working process continued in clinics in order to test and introduce new "coladerm"+ chlorhexidine covered poliprophilene meshes into practice. For clinical illustration there were 60 patients introduced to the research who had hernioplasty procedures by different nets: I group - standard meshes+"coladerm"+chlorhexidine, 35 patients; II group - standard meshes +"coladerm", 15 patients; III group - standard meshes, 10 patients. Assessment of the wound and echo-control was done post-surgery on the 8th, 30th and 90th days. This clinical research based on the experimental results once again showed the best anti-microbe features of new antiseptic polymeric biocomposite meshes (standard meshes+"coladerm"+chlorhexidine); timely termination of regeneration and reparation processes without any post-surgery suppurative complications. We hope that new antiseptic polymeric biocomposite meshes presented by us will be successfully used in surgical practice of hernia treatment based on and supported by expermental-clinical research.

Operation for recurrent cystocele with anterior colporrhaphy or non-absorbable mesh: patient reported outcomes

DEFF Research Database (Denmark)

Nüssler, Emil Karl; Greisen, Susanne; Kesmodel, Ulrik Schiøler

2013-01-01

Abstract INTRODUCTION AND HYPOTHESIS: The aim of this study was to compare patient reported outcomes and complications after repair of recurrent anterior vaginal wall prolapse in routine health care settings using standard anterior colporrhaphy or non-absorbable mesh. METHODS: The study is based...... on prospective data from the Swedish National Register for Gynaecological Surgery. 286 women were operated on for recurrent anterior vaginal wall prolapse in 2008-2010; 157 women had an anterior colporrhaphy and 129 were operated on with a non-absorbable mesh. Pre-, and perioperative data were collected from...... (0.6 %) in the anterior colporrhaphy group (p = 0.58). The infection rate was higher after mesh (8.5 %) than after anterior colporrhaphy (2.5 %; OR 3.19 ; 1.07-14.25). CONCLUSION: Implantation of synthetic mesh during operation for recurrent cystocele more than doubled the cure rate, whereas...

Laparoscopic mesh explantation and drainage of sacral abscess remote from transvaginal excision of exposed sacral colpopexy mesh.

Science.gov (United States)

Roth, Ted M; Reight, Ian

2012-07-01

Sacral colpopexy may be complicated by mesh exposure, and the surgical treatment of mesh exposure typically results in minor postoperative morbidity and few delayed complications. A 75-year-old woman presented 7 years after a laparoscopic sacral colpopexy, with Mersilene mesh, with an apical mesh exposure. She underwent an uncomplicated transvaginal excision and was asymptomatic until 8 months later when she presented with vaginal drainage and a sacral abscess. This was successfully treated with laparoscopic enterolysis, drainage of the abscess, and explantation of the remaining mesh. Incomplete excision of exposed colpopexy mesh can lead to ascending infection and sacral abscess. Laparoscopic drainage and mesh removal may be considered in these patients.

MeSH Now: automatic MeSH indexing at PubMed scale via learning to rank.

Science.gov (United States)

Mao, Yuqing; Lu, Zhiyong

2017-04-17

MeSH indexing is the task of assigning relevant MeSH terms based on a manual reading of scholarly publications by human indexers. The task is highly important for improving literature retrieval and many other scientific investigations in biomedical research. Unfortunately, given its manual nature, the process of MeSH indexing is both time-consuming (new articles are not immediately indexed until 2 or 3 months later) and costly (approximately ten dollars per article). In response, automatic indexing by computers has been previously proposed and attempted but remains challenging. In order to advance the state of the art in automatic MeSH indexing, a community-wide shared task called BioASQ was recently organized. We propose MeSH Now, an integrated approach that first uses multiple strategies to generate a combined list of candidate MeSH terms for a target article. Through a novel learning-to-rank framework, MeSH Now then ranks the list of candidate terms based on their relevance to the target article. Finally, MeSH Now selects the highest-ranked MeSH terms via a post-processing module. We assessed MeSH Now on two separate benchmarking datasets using traditional precision, recall and F 1 -score metrics. In both evaluations, MeSH Now consistently achieved over 0.60 in F-score, ranging from 0.610 to 0.612. Furthermore, additional experiments show that MeSH Now can be optimized by parallel computing in order to process MEDLINE documents on a large scale. We conclude that MeSH Now is a robust approach with state-of-the-art performance for automatic MeSH indexing and that MeSH Now is capable of processing PubMed scale documents within a reasonable time frame. http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/MeSHNow/ .

Alveolar Ridge Reconstruction with Titanium Meshes and Simultaneous Implant Placement: A Retrospective, Multicenter Clinical Study

Directory of Open Access Journals (Sweden)

Raquel Zita Gomes

2016-01-01

Full Text Available Objective. To evaluate horizontal bone gain and implant survival and complication rates in patients treated with titanium meshes placed simultaneously with dental implants and fixed over them. Methods. Twenty-five patients treated with 40 implants and simultaneous guided bone regeneration with titanium meshes (i–Gen®, MegaGen, Gyeongbuk, Republic of Korea were selected for inclusion in the present retrospective multicenter study. Primary outcomes were horizontal bone gain and implant survival; secondary outcomes were biological and prosthetic complications. Results. After the removal of titanium meshes, the CBCT evaluation revealed a mean horizontal bone gain of 3.67 mm (±0.89. The most frequent complications were mild postoperative edema (12/25 patients: 48% and discomfort after surgery (10/25 patients: 40%; these complications were resolved within one week. Titanium mesh exposure occurred in 6 patients (6/25 : 24%: one of these suffered partial loss of the graft and another experienced complete graft loss and implant failure. An implant survival rate of 97.5% (implant-based and a peri-implant marginal bone loss of 0.43 mm (±0.15 were recorded after 1 year. Conclusions. The horizontal ridge reconstruction with titanium meshes placed simultaneously with dental implants achieved predictable satisfactory results. Prospective randomized controlled trials on a larger sample of patients are required to validate these positive outcomes.

Mersiline mesh in premaxillary augmentation.

Science.gov (United States)

Foda, Hossam M T

2005-01-01

Premaxillary retrusion may distort the aesthetic appearance of the columella, lip, and nasal tip. This defect is characteristically seen in, but not limited to, patients with cleft lip nasal deformity. This study investigated 60 patients presenting with premaxillary deficiencies in which Mersiline mesh was used to augment the premaxilla. All the cases had surgery using the external rhinoplasty technique. Two methods of augmentation with Mersiline mesh were used: the Mersiline roll technique, for the cases with central symmetric deficiencies, and the Mersiline packing technique, for the cases with asymmetric deficiencies. Premaxillary augmentation with Mersiline mesh proved to be simple technically, easy to perform, and not associated with any complications. Periodic follow-up evaluation for a mean period of 32 months (range, 12-98 months) showed that an adequate degree of premaxillary augmentation was maintained with no clinically detectable resorption of the mesh implant.

Comparison of post-operative wound infection after inguinal hernia repair with polypropylene mesh and polyester mesh

International Nuclear Information System (INIS)

Mughal, M.A.; Ahmed, M.; Sajid, M.T.; Mustafa, Q.U.A.; Shukr, I.; Ahsan, J.

2012-01-01

Objective: To compare post operative wound infection frequency after inguinal hernia repair with polypropylene and polyester mesh using standard Lichtenstein hernioplasty technique. Study Design: Randomized controlled trial. Place and Duration: This study was conducted at general surgery department CMH/MH Rawalpindi from 8th April 2007 to 1st Jan 2008 over a period of 09 months. Patients and Materials: Sixty patients received through outpatient department with diagnosis of inguinal hernia satisfying inclusion/exclusion criteria were included. Patients were divided into two groups randomly. Group 1 included those patients in whom polypropylene mesh was used while group II patients were implanted with polyester mesh. Demographic as well as data concerning post operative wound infection was collected and analyzed. Results: Fifty seven patients (95%) were males while remaining (05%) were females. Mean age in group I was 41.17+-9.99 years while in group II was 41.47+-9.79 years (p=0.907). One patient (3.3%) in each group developed wound infection diagnosed by clinical evidence of pain at wound site, redness, induration and purulent discharge. Conclusion: There is no difference in post operative wound infection rate after inguinal Lichtenstein hernioplasty using either polypropylene or polyester mesh. (author)

Transrectal Mesh Erosion Requiring Bowel Resection.

Science.gov (United States)

Kemp, Marta Maria; Slim, Karem; Rabischong, Benoît; Bourdel, Nicolas; Canis, Michel; Botchorishvili, Revaz

To report a case of a transrectal mesh erosion as complication of laparoscopic promontofixation with mesh repair, necessitating bowel resection and subsequent surgical interventions. Sacrocolpopexy has become a standard procedure for vaginal vault prolapse [1], and the laparoscopic approach has gained popularity owing to more rapid recovery and less morbidity [2,3]. Mesh erosion is a well-known complication of surgical treatment for prolapse as reported in several negative evaluations, including a report from the US Food and Drug Administration in 2011 [4]. Mesh complications are more common after surgeries via the vaginal approach [5]; nonetheless, the incidence of vaginal mesh erosion after laparoscopic procedures is as high as 9% [6]. The incidence of transrectal mesh exposure after laparoscopic ventral rectopexy is roughly 1% [7]. The diagnosis may be delayed because of its rarity and variable presentation. In addition, polyester meshes, such as the mesh used in this case, carry a higher risk of exposure [8]. A 57-year-old woman experiencing genital prolapse, with the cervix classified as +3 according to the Pelvic Organ Prolapse Quantification system, underwent laparoscopic standard sacrocolpopexy using polyester mesh. Subtotal hysterectomy and bilateral adnexectomy were performed concomitantly. A 3-year follow-up consultation demonstrated no signs or symptoms of erosion of any type. At 7 years after the surgery, however, the patient presented with rectal discharge, diagnosed as infectious rectocolitis with the isolation of Clostridium difficile. She underwent a total of 5 repair surgeries in a period of 4 months, including transrectal resection of exposed mesh, laparoscopic ablation of mesh with digestive resection, exploratory laparoscopy with abscess drainage, and exploratory laparoscopy with ablation of residual mesh and transverse colostomy. She recovered well after the last intervention, exhibiting no signs of vaginal or rectal fistula and no recurrence

Obturator foramen dissection for excision of symptomatic transobturator mesh.

Science.gov (United States)

Reynolds, W Stuart; Kit, Laura Chang; Kaufman, Melissa R; Karram, Mickey; Bales, Gregory T; Dmochowski, Roger R

2012-05-01

Groin pain after transobturator synthetic mesh placement can be recalcitrant to conservative therapy and ultimately requires surgical excision. We describe our experiences with and technique of obturator foramen dissection for mesh excision. The records of 8 patients treated from 2005 to 2010, were reviewed. Obturator dissection was performed via a lateral groin incision over the inferior pubic ramus at the level of the obturator foramen, typically in conjunction with orthopedic surgery. Five patients had transobturator mid urethral sling surgery for stress urinary incontinence, 2 had mid urethral sling and trocar based anterior vaginal wall mesh kits with transobturator passage of mesh arms for stress urinary incontinence and pelvic organ prolapse, and 1 had an anterior vaginal wall mesh kit for pelvic organ prolapse. Patients had 0 to 2 prior transvaginal mesh excisions before obturator surgery. All patients presented with intractable pain in the area of the obturator foramen and/or medial groin for which conservative treatment measures had failed. Six patients underwent concurrent vaginal and obturator dissection and 2 underwent obturator dissection alone. In all cases residual mesh (3 to 11 cm) was identified and excised from the obturator foramen. Mesh was closely associated to or traversing the adductor longus muscle and tendon with significant fibrous reaction in all cases. Postoperatively 5 patients were cured of pain and/or infection, and 3 reported no or some improvement at a mean followup of 6 months (range 1 to 12). Our experience suggests that surgical excision of residual mesh can alleviate many of the symptoms in many patients. In all cases mesh remnants were identified and removed, and typically involved neuromuscular structures adjacent to the obturator foramen. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Surface mesh to voxel data registration for patient-specific anatomical modeling

Science.gov (United States)

de Oliveira, Júlia E. E.; Giessler, Paul; Keszei, András.; Herrler, Andreas; Deserno, Thomas M.

2016-03-01

Virtual Physiological Human (VPH) models are frequently used for training, planning, and performing medical procedures. The Regional Anaesthesia Simulator and Assistant (RASimAs) project has the goal of increasing the application and effectiveness of regional anesthesia (RA) by combining a simulator of ultrasound-guided and electrical nerve-stimulated RA procedures and a subject-specific assistance system through an integration of image processing, physiological models, subject-specific data, and virtual reality. Individualized models enrich the virtual training tools for learning and improving regional anaesthesia (RA) skills. Therefore, we suggest patient-specific VPH models that are composed by registering the general mesh-based models with patient voxel data-based recordings. Specifically, the pelvis region has been focused for the support of the femoral nerve block. The processing pipeline is composed of different freely available toolboxes such as MatLab, the open Simulation framework (SOFA), and MeshLab. The approach of Gilles is applied for mesh-to-voxel registration. Personalized VPH models include anatomical as well as mechanical properties of the tissues. Two commercial VPH models (Zygote and Anatomium) were used together with 34 MRI data sets. Results are presented for the skin surface and pelvic bones. Future work will extend the registration procedure to cope with all model tissue (i.e., skin, muscle, bone, vessel, nerve, fascia) in a one-step procedure and extrapolating the personalized models to body regions actually being out of the captured field of view.

3-year results of transvaginal cystocele repair with transobturator four-arm mesh: A prospective study of 105 patients

OpenAIRE

Kdous, Moez; Zhioua, Fethi

2014-01-01

Objectives To evaluate the long-term efficacy and safety of transobturator four-arm mesh for treating cystoceles. Patients and methods In this prospective study, 105 patients had a cystocele corrected between January 2004 and December 2008. All patients had a symptomatic cystocele of stage ?2 according to the Baden?Walker halfway stratification. We used only the transobturator four-arm mesh kit (Surgimesh?, Aspide Medical, France). All surgical procedures were carried out by the same experien...

Mesh Optimization for Ground Vehicle Aerodynamics

OpenAIRE

Adrian Gaylard; Essam F Abo-Serie; Nor Elyana Ahmad

2010-01-01

Mesh optimization strategy for estimating accurate drag of a ground vehicle is proposed based on examining the effect of different mesh parameters.  The optimized mesh parameters were selected using design of experiment (DOE) method to be able to work in a...

Theoretical study of the influence of twine thickness on haddock selectivity in diamond mesh cod-ends

DEFF Research Database (Denmark)

Herrmann, Bent; O'Neill, F.G.

2006-01-01

Using the cod-end simulation model PRESEMO, the influence of twine thickness on cod-end selectivity is investigated. The reduction of lateral mesh opening that arises as a result of both twine bending stiffness and the physical presence of the twine is considered. While it is shown that this lead...

On Reducing Delay in Mesh-Based P2P Streaming: A Mesh-Push Approach

Science.gov (United States)

Liu, Zheng; Xue, Kaiping; Hong, Peilin

The peer-assisted streaming paradigm has been widely employed to distribute live video data on the internet recently. In general, the mesh-based pull approach is more robust and efficient than the tree-based push approach. However, pull protocol brings about longer streaming delay, which is caused by the handshaking process of advertising buffer map message, sending request message and scheduling of the data block. In this paper, we propose a new approach, mesh-push, to address this issue. Different from the traditional pull approach, mesh-push implements block scheduling algorithm at sender side, where the block transmission is initiated by the sender rather than by the receiver. We first formulate the optimal upload bandwidth utilization problem, then present the mesh-push approach, in which a token protocol is designed to avoid block redundancy; a min-cost flow model is employed to derive the optimal scheduling for the push peer; and a push peer selection algorithm is introduced to reduce control overhead. Finally, we evaluate mesh-push through simulation, the results of which show mesh-push outperforms the pull scheduling in streaming delay, and achieves comparable delivery ratio at the same time.

Symptom resolution after operative management of complications from transvaginal mesh.

Science.gov (United States)

Crosby, Erin C; Abernethy, Melinda; Berger, Mitchell B; DeLancey, John O; Fenner, Dee E; Morgan, Daniel M

2014-01-01

Complications from transvaginal mesh placed for prolapse often require operative management. The aim of this study is to describe the outcomes of vaginal mesh removal. A retrospective review of all patients having surgery by the urogynecology group in the department of obstetrics and gynecology at our institution for a complication of transvaginal mesh placed for prolapse was performed. Demographics, presenting symptoms, surgical procedures, and postoperative symptoms were abstracted. Comparative statistics were performed using the χ or Fisher's exact test with significance at Pmesh and 84 had follow-up data. The most common presenting signs and symptoms were: mesh exposure, 62% (n=56); pain, 64% (n=58); and dyspareunia, 48% (n=43). During operative management, mesh erosion was encountered unexpectedly in a second area of the vagina in 5% (n=4), in the bladder in 1% (n=1), and in the bowel in 2% (n=2). After vaginal mesh removal, 51% (n=43) had resolution of all presenting symptoms. Mesh exposure was treated successfully in 95% of patients, whereas pain was only successfully treated in 51% of patients. Removal of vaginal mesh is helpful in relieving symptoms of presentation. Patients can be reassured that exposed mesh can almost always be successfully managed surgically, but pain and dyspareunia are only resolved completely in half of patients. III.

Chronic pain after liechtenstein mesh repair for inguinla hernia a review of 114 patients

International Nuclear Information System (INIS)

Shah, S.F.; Hameed, S.; Aurakzai, J.K.; Chaudry, MA.

2015-01-01

Objective: To determine factors related to chronic persistent pain lasting more than 6 months after mesh repair for inguinal hernia. Methodology: This study included 114 patients who underwent elective inguinal hernioplasty at Department of General Surgery, Federal General Hospital, Islamabad, Pakistan from July 2012 to December 2014. All were followed upto end of six months. Postoperatively pain was recorded at second, seventh and fourteen day and at the end of six months on Visual Analogue Scale. Results: Chronic pain at six-month follow up was present in 37 (32.45%) patients. The incidence of factors responsible for chronic pain were pain before surgery in 22 (19.29%), early postoperative pain in 10 (8.77%) of patients, wound infection in 2 (1.75%), hematoma formation in 3 (2.63%), and seroma formation in 4 (3.508%) patients. Conclusion: Chronic pain after mesh repair for inguinal hernia causes significant morbidity. Early recognition and management of the factors prevents patient morbidity. (author)

BIOLOGICAL AND SYNTHETIC MESH USE IN RECONSTRUCTIVE SURGERY IN PATIENTS WITH BREAST CANCER

Directory of Open Access Journals (Sweden)

M. V. Ermoshchenkova

2017-01-01

Full Text Available Introduction. In recent years, considerable success has been achieved in complex and combined treatment of breast cancer (BC. Reconstructive plastic surgery plays an important role in the rehabilitation of patients with breast cancer and it is currently considered as the causal treatment of mental disorders caused by loss of femininity and integrity of one’s own body. One-step breast reconstruction for cancer treatment makes it possible to use supplementary materials — synthetic and biological implants that can replace muscle autografts and thereby reduce trauma, blood loss, operation time, and thereby help to avoid the defect of donor areas. The authors describe the state of the art at present and demonstrate the results of their own research.Materials and methods. The object of study was 38 of breast cancer cases and 1 case of multiple gelioma caused by silicone implant rupture. 44 operations have been completed: 21 — radical subcutaneous mastectomy, 1 — subcutaneous mastectomy, 17 — skin-sparing radical mastectomy with one-step reconstruction with mesh implant (12 — titanium, 16 — polyester, 11 — acellular dermal matrix Permacol, 5 — prophylactic contralateral subcutaneous mastectomy with one-step reconstruction with silicone implant and a mesh implant due to a mutation of the BRCA1 gene. The technique of operations and the results of studies have been described in detail.Results. In the late post-operational period, the implants were removed in 5 cases: in 2 patients due to the development of inflammation of ADM, 3 — in connection with the development of bedsores and diastasis of the skin in the wound area when synthetic implants were used. From the total number of patients in the group (n = 39 excellent cosmetic results were reported in 21 cases (54%, good — in 13 (33% and unsatisfactory — in 5 (13% cases due to the removal of the implants.Conclusions. Biological and synthetic materials are significantly important

Anisotropic evaluation of synthetic surgical meshes.

Science.gov (United States)

Saberski, E R; Orenstein, S B; Novitsky, Y W

2011-02-01

The material properties of meshes used in hernia repair contribute to the overall mechanical behavior of the repair. The anisotropic potential of synthetic meshes, representing a difference in material properties (e.g., elasticity) in different material axes, is not well defined to date. Haphazard orientation of anisotropic mesh material can contribute to inconsistent surgical outcomes. We aimed to characterize and compare anisotropic properties of commonly used synthetic meshes. Six different polypropylene (Trelex(®), ProLite™, Ultrapro™), polyester (Parietex™), and PTFE-based (Dualmesh(®), Infinit) synthetic meshes were selected. Longitudinal and transverse axes were defined for each mesh, and samples were cut in each axis orientation. Samples underwent uniaxial tensile testing, from which the elastic modulus (E) in each axis was determined. The degree of anisotropy (λ) was calculated as a logarithmic expression of the ratio between the elastic modulus in each axis. Five of six meshes displayed significant anisotropic behavior. Ultrapro™ and Infinit exhibited approximately 12- and 20-fold differences between perpendicular axes, respectively. Trelex(®), ProLite™, and Parietex™ were 2.3-2.4 times. Dualmesh(®) was the least anisotropic mesh, without marked difference between the axes. Anisotropy of synthetic meshes has been underappreciated. In this study, we found striking differences between elastic properties of perpendicular axes for most commonly used synthetic meshes. Indiscriminate orientation of anisotropic mesh may adversely affect hernia repairs. Proper labeling of all implants by manufacturers should be mandatory. Understanding the specific anisotropic behavior of synthetic meshes should allow surgeons to employ rational implant orientation to maximize outcomes of hernia repair.

Current role of mesh in vaginal prolapse surgery.

Science.gov (United States)

Richter, Lee A; Carter, Charelle; Gutman, Robert E

2014-10-01

This report summarizes the latest literature on transvaginal mesh (TVM) for the treatment of pelvic organ prolapse, with a focus on indications for use and management of complications. We describe trends in TVM by reviewing the recent literature and summarizing national meeting presentations. Vaginal mesh complications are most often managed surgically, and the majority of patients experiencing mesh-related pain have symptom improvement after intervention. New efforts will focus on identifying variables associated with success after intervention for mesh-related complications, to aid reconstructive pelvic surgeons in outcome prediction and patient counselling. Although the use of TVM has plateaued in recent years, we are seeing an exponential rise in synthetic mesh implant removal. Reconstructive pelvic surgeons advising patients with TVM complications should report that surgical intervention is often necessary, improvement rates of pain-related symptoms after surgery are high, and up to a third may require multiple interventions.

Convergence study of global meshing on enamel-cement-bracket finite element model

Science.gov (United States)

Samshuri, S. F.; Daud, R.; Rojan, M. A.; Basaruddin, K. S.; Abdullah, A. B.; Ariffin, A. K.

2017-09-01

This paper presents on meshing convergence analysis of finite element (FE) model to simulate enamel-cement-bracket fracture. Three different materials used in this study involving interface fracture are concerned. Complex behavior ofinterface fracture due to stress concentration is the reason to have a well-constructed meshing strategy. In FE analysis, meshing size is a critical factor that influenced the accuracy and computational time of analysis. The convergence study meshing scheme involving critical area (CA) and non-critical area (NCA) to ensure an optimum meshing sizes are acquired for this FE model. For NCA meshing, the area of interest are at the back of enamel, bracket ligature groove and bracket wing. For CA meshing, area of interest are enamel area close to cement layer, the cement layer and bracket base. The value of constant NCA meshing tested are meshing size 1 and 0.4. The value constant CA meshing tested are 0.4 and 0.1. Manipulative variables are randomly selected and must abide the rule of NCA must be higher than CA. This study employed first principle stresses due to brittle failure nature of the materials used. Best meshing size are selected according to convergence error analysis. Results show that, constant CA are more stable compare to constant NCA meshing. Then, 0.05 constant CA meshing are tested to test the accuracy of smaller meshing. However, unpromising result obtained as the errors are increasing. Thus, constant CA 0.1 with NCA mesh of 0.15 until 0.3 are the most stable meshing as the error in this region are lowest. Convergence test was conducted on three selected coarse, medium and fine meshes at the range of NCA mesh of 0.15 until 3 and CA mesh area stay constant at 0.1. The result shows that, at coarse mesh 0.3, the error are 0.0003% compare to 3% acceptable error. Hence, the global meshing are converge as the meshing size at CA 0.1 and NCA 0.15 for this model.

Opfront: mesh

DEFF Research Database (Denmark)

2015-01-01

Mesh generation and visualization software based on the CGAL library. Folder content: drawmesh Visualize slices of the mesh (surface/volumetric) as wireframe on top of an image (3D). drawsurf Visualize surfaces of the mesh (surface/volumetric). img2mesh Convert isosurface in image to volumetric m...... mesh (medit format). img2off Convert isosurface in image to surface mesh (off format). off2mesh Convert surface mesh (off format) to volumetric mesh (medit format). reduce Crop and resize 3D and stacks of images. data Example data to test the library on...

Scalable power selection method for wireless mesh networks

CSIR Research Space (South Africa)

Olwal, TO

2009-01-01

Full Text Available This paper addresses the problem of a scalable dynamic power control (SDPC) for wireless mesh networks (WMNs) based on IEEE 802.11 standards. An SDPC model that accounts for architectural complexities witnessed in multiple radios and hops...

Selectivity of Standard, Narrow and Square Mesh Panel Trawl Codends for Hake (Merluccius merluccius) and Poor Cod (Trisopterus minutus capelanus)

OpenAIRE

ÖZBİLGİN, Hüseyin; TOSUNOĞLU, Zafer; AYDIN, Celalettin; KAYKAÇ, Hakan; TOKAÇ, Adnan

2005-01-01

The selectivity of 3 trawl codends, (1) a commercially used standard codend, (2) a narrow codend (100 meshes on its circumference instead of 200) and (3) a square mesh top panel codend, was tested for hake (Merluccius merluccius) and poor cod (Trisopterus minutus capelanus) between 8 and 24 October 2003, in the Aegean Sea. Data were collected using the covered codend technique, and analysed by means of a logistic equation with the maximum likelihood method. The results show that the commer...

Evaluation of mesh morphing and mapping techniques in patient specific modeling of the human pelvis.

Science.gov (United States)

Salo, Zoryana; Beek, Maarten; Whyne, Cari Marisa

2013-01-01

Robust generation of pelvic finite element models is necessary to understand the variation in mechanical behaviour resulting from differences in gender, aging, disease and injury. The objective of this study was to apply and evaluate mesh morphing and mapping techniques to facilitate the creation and structural analysis of specimen-specific finite element (FE) models of the pelvis. A specimen-specific pelvic FE model (source mesh) was generated following a traditional user-intensive meshing scheme. The source mesh was morphed onto a computed tomography scan generated target surface of a second pelvis using a landmarked-based approach, in which exterior source nodes were shifted to target surface vertices, while constrained along a normal. A second copy of the morphed model was further refined through mesh mapping, in which surface nodes of the initial morphed model were selected in patches and remapped onto the surfaces of the target model. Computed tomography intensity based material properties were assigned to each model. The source, target, morphed and mapped models were analyzed under axial compression using linear static FE analysis and their strain distributions evaluated. Morphing and mapping techniques were effectively applied to generate good quality geometrically complex specimen-specific pelvic FE models. Mapping significantly improved strain concurrence with the target pelvis FE model. Copyright © 2012 John Wiley & Sons, Ltd.

Evaluation of mesh morphing and mapping techniques in patient specific modelling of the human pelvis.

Science.gov (United States)

Salo, Zoryana; Beek, Maarten; Whyne, Cari Marisa

2012-08-01

Robust generation of pelvic finite element models is necessary to understand variation in mechanical behaviour resulting from differences in gender, aging, disease and injury. The objective of this study was to apply and evaluate mesh morphing and mapping techniques to facilitate the creation and structural analysis of specimen-specific finite element (FE) models of the pelvis. A specimen-specific pelvic FE model (source mesh) was generated following a traditional user-intensive meshing scheme. The source mesh was morphed onto a computed tomography scan generated target surface of a second pelvis using a landmarked-based approach, in which exterior source nodes were shifted to target surface vertices, while constrained along a normal. A second copy of the morphed model was further refined through mesh mapping, in which surface nodes of the initial morphed model were selected in patches and remapped onto the surfaces of the target model. Computed tomography intensity-based material properties were assigned to each model. The source, target, morphed and mapped models were analyzed under axial compression using linear static FE analysis, and their strain distributions were evaluated. Morphing and mapping techniques were effectively applied to generate good quality and geometrically complex specimen-specific pelvic FE models. Mapping significantly improved strain concurrence with the target pelvis FE model. Copyright © 2012 John Wiley & Sons, Ltd.

Reconstructive laparoscopic prolapse surgery to avoid mesh erosions

Directory of Open Access Journals (Sweden)

Devassy, Rajesh

2013-09-01

Full Text Available Introduction: The objective of the study is to examine the efficacy of the purely laparoscopic reconstructive management of cystocele and rectocele with mesh, to avoid the risk of erosion by the graft material, a well known complication in vaginal mesh surgery. Material and methods: We performed a prospective, single-case, non-randomized study in 325 patients who received laparoscopic reconstructive management of pelvic organe prolaps with mesh. The study was conducted between January 2004 and December 2012 in a private clinic in India. The most common prolapse symptoms were reducible vaginal lump, urinary stress incontinence, constipation and flatus incontinence, sexual dysfunction and dypareunia. The degree e of the prolaps was staged according to POPQ system. The approach was purely laparoscopic and involved the use of polypropylene (Prolene or polyurethane with activated regenerated cellulose coating (Parietex mesh. Results: The mean age was 55 (30–80 years and the most of the patients were multiparous (272/325. The patients received a plastic correction of the rectocele only (138 cases, a cystocele and rectocele (187 cases with mesh. 132 patients had a concomitant total hysterectomy; in 2 cases a laparoscopic supracervical hysterectomy was performed and 190 patients had a laparoscopic colposuspension. The mean operation time was 82.2 (60–210 minutes. The mean follow up was 3.4 (3–5 years. Urinary retention developed in 1 case, which required a new laparoscopical intervention. Bladder injury, observed in the same case was in one session closed with absorbable suture. There were four recurrences of the rectocele, receiving a posterior vaginal colporrhaphy. Erosions of the mesh were not reported or documented. Conclusion: The pure laparoscopic reconstructive management of the cystocele and rectocele with mesh seems to be a safe and effective surgical procedure potentially avoiding the risk of mesh erosions.

Documentation for MeshKit - Reactor Geometry (&mesh) Generator

Energy Technology Data Exchange (ETDEWEB)

Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-30

This report gives documentation for using MeshKit’s Reactor Geometry (and mesh) Generator (RGG) GUI and also briefly documents other algorithms and tools available in MeshKit. RGG is a program designed to aid in modeling and meshing of complex/large hexagonal and rectilinear reactor cores. RGG uses Argonne’s SIGMA interfaces, Qt and VTK to produce an intuitive user interface. By integrating a 3D view of the reactor with the meshing tools and combining them into one user interface, RGG streamlines the task of preparing a simulation mesh and enables real-time feedback that reduces accidental scripting mistakes that could waste hours of meshing. RGG interfaces with MeshKit tools to consolidate the meshing process, meaning that going from model to mesh is as easy as a button click. This report is designed to explain RGG v 2.0 interface and provide users with the knowledge and skills to pilot RGG successfully. Brief documentation of MeshKit source code, tools and other algorithms available are also presented for developers to extend and add new algorithms to MeshKit. RGG tools work in serial and parallel and have been used to model complex reactor core models consisting of conical pins, load pads, several thousands of axially varying material properties of instrumentation pins and other interstices meshes.

Vacuum assisted closure therapy in the treatment of mesh infection after hernia repair.

Science.gov (United States)

Tamhankar, A P; Ravi, K; Everitt, N J

2009-10-01

Mesh related infection after prosthetic abdominal wall hernia repair is a difficult clinical problem, particularly in an era of evolving microbial resistance. Commonly advocated treatment for such infection involves complete mesh excision which usually leaves a complicated weak wound. We report the use ofVAC therapy for mesh infections that allows mesh preservation leaving a sound wound. From june 2002 to January 2007, four patients with mesh related infection after abdominal wall hernia repair were treated with VAC therapy. Patients' notes were reviewed to gather clinical details. Mesh infection was evident after a variable period (day three to eight years) following hernia repair. Of the four patients, one had infection with methicillin resistant Staphylococcus aureus (MRSA), while the bacteriological cultures from two confirmed Staphylococcus aureus in one and a mixture of Pseudomonas and enterococcus species in the other. One patient failed to show significant bacterial growth on pus swab culture, having had prior broad-spectrum antibiotic treatment for mesh infection. Three patients had complete mesh preservation and one had partial mesh excision. All patients were treated with VAC therapy, following the drainage of their operation sites, until the visible mesh was covered with granulation (one to seven weeks). No patient had a recurrent hernia after complete wound healing. VAC therapy allows salvage of infected exposed mesh by promoting granulation through the mesh. Judicious use of VAC therapy may prevent the need of mesh excision and its wound related complications.

Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

Science.gov (United States)

Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

2016-10-01

Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

Incisional hernia prevention using a cyanoacrilate-fixed retrofascial mesh.

Science.gov (United States)

Hoyuela, Carlos; Juvany, Montserrat; Trias, Miquel; Ardid, Jordi; Martrat, Antoni

2018-01-01

The rate of incisional hernia in high-risk patients (obesity, cancer, etc.) is high, even in laparoscopic surgery. The aim of this study is to evaluate the safety of the use of cyanoacrylate fixed prophylactic meshes in the assistance incision in overweight or obese patients undergoing laparoscopic colorectal surgery. A prospective, non-randomized cohort study of patients undergoing elective laparoscopic resection for colorectal cancer between January 2013 and March 2016 was performed. Those with a body mass index greater than 25kg / m 2 were evaluated to implant a prophylactic meshes fixed with cyanoacrylate (Histoacryl®) as reinforcement of the assistance incision. 52 patients were analyzed (mean body mass index: 28.4±2kg / m 2 ). Prophylactic meshes was implanted in 15 patients. The time to put the mesh in place was always less than 5minutes. There was no significant difference in wound infection rate (12% vs. 10%). No mesh had to be explanted. Although the mean follow-up was shorter (14.1±4 vs. 22.3±9 months), there were no incisional hernia in the mesh group. On the other hand, in the non-mesh group, 1 acute evisceration (2.7%) and 4 incisional hernia of the assistance incision were observed (10.8%). There were no significant differences between groups regarding trocar incisional hernia (6.6 vs. 5.4%). The implantation of a reinforcement prophylactic mesh in overweight or obese patients undergoing laparoscopic colorectal surgery is safe and seems to reduce the short-term rate of incisional hernia. Fixation with cyanoacrylate is a rapid method that facilitates the procedure without additional complications. Copyright © 2017 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Management of complications arising from transvaginal mesh kit procedures: a tertiary referral center's experience.

Science.gov (United States)

Hurtado, Eric A; Appell, Rodney A

2009-01-01

This case series' purpose is to review a referral center's experience with complications from mesh kits. A chart review of 12 patients who presented with complications associated with transvaginal mesh kit procedures was performed. All patients underwent complete surgical removal of the mesh to treat mesh exposure, pain, or vaginal bleeding/discharge followed by an anterior or posterior repair. The mean follow-up time after surgery was 3.4 months. Eight of 12 patients had mesh that had formed a fibrotic band. Six of 12 patients had complete resolution of pain. Of the nine patients with mesh exposure, all required significant resection of the vaginal wall. No further mesh exposure occurred. The use of transvaginal mesh kits may cause previously undescribed complications such as pelvic/vaginal pain or large extrusions requiring complete removal. Removal of all mesh except the arms may cure or significantly improve these problems.

Mesh-graft urethroplasty: a case report

OpenAIRE

田中, 敏博; 滝川, 浩; 香川, 征; 長江, 浩朗

1987-01-01

We used a meshed free-foreskin transplant in a two-stage procedure for reconstruction of the extended stricture of urethra after direct vision urethrotomy. The results were excellent. Mesh-graft urethroplasty is a useful method for patients with extended strictures of the urethra or recurrent strictures after several operations.

Transvaginal mesh procedures for pelvic organ prolapse.

Science.gov (United States)

Walter, Jens-Erik

2011-02-01

To provide an update on transvaginal mesh procedures, newly available minimally invasive surgical techniques for pelvic floor repair. The discussion is limited to minimally invasive transvaginal mesh procedures. PubMed and Medline were searched for articles published in English, using the key words "pelvic organ prolapse," transvaginal mesh," and "minimally invasive surgery." Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. Searches were updated on a regular basis, and articles were incorporated in the guideline to May 2010. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on the Preventive Health Care. Recommendations for practice were ranked according to the method described in that report (Table 1). Counselling for the surgical treatment of pelvic organ prolapse should consider all benefits, harms, and costs of the surgical procedure, with particular emphasis on the use of mesh. 1. Patients should be counselled that transvaginal mesh procedures are considered novel techniques for pelvic floor repair that demonstrate high rates of anatomical cure in uncontrolled short-term case series. (II-2B) 2. Patients should be informed of the range of success rates until stronger evidence of superiority is published. (II-2B) 3. Training specific to transvaginal mesh procedures should be undertaken before procedures are performed. (III-C) 4. Patients should undergo thorough preoperative counselling regarding (a) the potential serious adverse sequelae of transvaginal mesh repairs, including mesh exposure, pain, and dyspareunia; and (b) the limited data available

Coarse mesh code development

Energy Technology Data Exchange (ETDEWEB)

Lieberoth, J.

1975-06-15

The numerical solution of the neutron diffusion equation plays a very important role in the analysis of nuclear reactors. A wide variety of numerical procedures has been proposed, at which most of the frequently used numerical methods are fundamentally based on the finite- difference approximation where the partial derivatives are approximated by the finite difference. For complex geometries, typical of the practical reactor problems, the computational accuracy of the finite-difference method is seriously affected by the size of the mesh width relative to the neutron diffusion length and by the heterogeneity of the medium. Thus, a very large number of mesh points are generally required to obtain a reasonably accurate approximate solution of the multi-dimensional diffusion equation. Since the computation time is approximately proportional to the number of mesh points, a detailed multidimensional analysis, based on the conventional finite-difference method, is still expensive even with modern large-scale computers. Accordingly, there is a strong incentive to develop alternatives that can reduce the number of mesh-points and still retain accuracy. One of the promising alternatives is the finite element method, which consists of the expansion of the neutron flux by piecewise polynomials. One of the advantages of this procedure is its flexibility in selecting the locations of the mesh points and the degree of the expansion polynomial. The small number of mesh points of the coarse grid enables to store the results of several of the least outer iterations and to calculate well extrapolated values of them by comfortable formalisms. This holds especially if only one energy distribution of fission neutrons is assumed for all fission processes in the reactor, because the whole information of an outer iteration is contained in a field of fission rates which has the size of all mesh points of the coarse grid.

Oral, intestinal, and skin bacteria in ventral hernia mesh implants

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Odd Langbach

2016-07-01

Full Text Available Background: In ventral hernia surgery, mesh implants are used to reduce recurrence. Infection after mesh implantation can be a problem and rates around 6–10% have been reported. Bacterial colonization of mesh implants in patients without clinical signs of infection has not been thoroughly investigated. Molecular techniques have proven effective in demonstrating bacterial diversity in various environments and are able to identify bacteria on a gene-specific level. Objective: The purpose of this study was to detect bacterial biofilm in mesh implants, analyze its bacterial diversity, and look for possible resemblance with bacterial biofilm from the periodontal pocket. Methods: Thirty patients referred to our hospital for recurrence after former ventral hernia mesh repair, were examined for periodontitis in advance of new surgical hernia repair. Oral examination included periapical radiographs, periodontal probing, and subgingival plaque collection. A piece of mesh (1×1 cm from the abdominal wall was harvested during the new surgical hernia repair and analyzed for bacteria by PCR and 16S rRNA gene sequencing. From patients with positive PCR mesh samples, subgingival plaque samples were analyzed with the same techniques. Results: A great variety of taxa were detected in 20 (66.7% mesh samples, including typical oral commensals and periodontopathogens, enterics, and skin bacteria. Mesh and periodontal bacteria were further analyzed for similarity in 16S rRNA gene sequences. In 17 sequences, the level of resemblance between mesh and subgingival bacterial colonization was 98–100% suggesting, but not proving, a transfer of oral bacteria to the mesh. Conclusion: The results show great bacterial diversity on mesh implants from the anterior abdominal wall including oral commensals and periodontopathogens. Mesh can be reached by bacteria in several ways including hematogenous spread from an oral site. However, other sites such as gut and skin may also

Mesh Migration into the J-Pouch in a Patient with Post-Ulcerative Colitis Colectomy: A Case Report and Literature Review

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Asem Ghanim

2017-01-01

Full Text Available Mesh repair offers advantages like lower postsurgical pain and earlier return to work. Thus, it has become a widely used treatment option. Here, we present the first case report of a mesh migration into a J-pouch in a patient with history of ulcerative colitis who underwent total abdominal colectomy with J-pouch and ileoanal anastomosis and a subsequent laparoscopic ventral hernia repair with mesh.

Abdominal wall hernia repair with a composite ePTFE/polypropylene mesh: clinical outcome and quality of life in 152 patients

DEFF Research Database (Denmark)

Iversen, E; Lykke, Anna; Hensler, M

2010-01-01

No consensus has yet been reached regarding the optimal mesh for the repair of small ventral hernias. A composite polytetrafluoroethylene/polypropylene mesh (Ventralex(®)) is designed for this purpose, and this paper reports its use in a larger series of patients....

Clinical study for pancreatic fistula after distal pancreatectomy with mesh reinforcement

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Akira Hayashibe

2018-05-01

Full Text Available Summary: Background: The purpose of this cohort study was to determine whether distal pancreatectomy with mesh reinforcement can reduce postoperative pancreatic fistula (POPF rates compared with bare stapler. Methods: In total, 51 patients underwent stapled distal pancreatectomy. Out of these, 22 patients (no mesh group underwent distal pancreatectomy with bare stapler and 29 patients (mesh group underwent distal pancreatectomy with mesh reinforced stapler. The risk factor for clinically relevant POPF (grades B and C after distal pancreatectomy was also evaluated. Results: Clinical characteristics were almost similar in both the groups. The days of the mean hospital stay and drainage tube insertion in the mesh group were significantly fewer than those in the no mesh group. The mean level of amylase in the discharge fluid in the mesh group was also significantly lower than that the in no mesh group. The rate of clinically relevant POPF (grades B and C in the mesh group was significantly lower than that in the no mesh group (p=0.016. Univariate analyses of risk factors for POPF (grades B and C revealed that only mesh reinforcement was associated with POPF (grades B and C. Moreover, on multivariate analyses of POPF risk factors with p value<0.2 in univariate analyses by logistic regression, mesh reinforcement was regarded as a significant factor for POPF(grades B and C. Conclusions: The distal pancreatectomy with mesh reinforced stapler was thought to be favorable for the prevention of clinically relevant POPF (grades B and C. Keywords: mesh reinforcement, pancreatic fistula, pancreatic surgery

3-year results of transvaginal cystocele repair with transobturator four-arm mesh: A prospective study of 105 patients.

Science.gov (United States)

Kdous, Moez; Zhioua, Fethi

2014-12-01

To evaluate the long-term efficacy and safety of transobturator four-arm mesh for treating cystoceles. In this prospective study, 105 patients had a cystocele corrected between January 2004 and December 2008. All patients had a symptomatic cystocele of stage ⩾2 according to the Baden-Walker halfway stratification. We used only the transobturator four-arm mesh kit (Surgimesh®, Aspide Medical, France). All surgical procedures were carried out by the same experienced surgeon. The patients' characteristics and surgical variables were recorded prospectively. The anatomical outcome, as measured by a physical examination and postoperative stratification of prolapse, and functional outcome, as assessed by a questionnaire derived from the French equivalents of the Pelvic Floor Distress Inventory, Pelvic Floor Impact Questionnaire and the Pelvic Organ Prolapse-Urinary Incontinence-Sexual Questionnaire, were considered as the primary outcome measures. Peri- and postoperative complications constituted the secondary outcome measures. At 36 months after surgery the anatomical success rate (stage 0 or 1) was 93%. On a functional level, all the scores of quality of life and sexuality were improved. The overall satisfaction score (visual analogue scale) was 71.4%. There were no perioperative adverse events. Mesh erosion was reported in 7.6% and mesh retraction in 5.7% of the patients. If the guidelines and precautions are followed, vaginal prosthetic surgery for genitourinary prolapse has shown long-term benefits. It provides excellent results both anatomically and functionally. However, complications are not negligible and some are specific to prosthetic surgery.

Surgical excision of eroded mesh after prior abdominal sacrocolpopexy.

Science.gov (United States)

South, Mary M T; Foster, Raymond T; Webster, George D; Weidner, Alison C; Amundsen, Cindy L

2007-12-01

We previously described an endoscopic-assisted transvaginal mesh excision technique. This study compares surgical outcomes after transvaginal mesh excision vs endoscopic-assisted transvaginal mesh excision. In addition, we reviewed our postoperative outcomes with excision via laparotomy. This was an inclusive retrospective analysis of patients presenting to our institution from 1997 to 2006 for surgical management of vaginal erosion of permanent mesh after sacrocolpopexy. Three techniques were utilized: transvaginal, endoscopic-assisted transvaginal, and laparotomy. For the patients undergoing transvaginal excision, data recorded included number and type of excisions performed, number of prior excisions performed at outside facilities, intraoperative and postoperative complications (including blood transfusions, pelvic abscess, or bowel complications), use of postoperative antibiotics, persistent symptoms of vaginal bleeding and discharge at follow-up, and demographic characteristics. The intraoperative and postoperative complications and the postoperative symptoms were recorded for the laparotomy cases. Thirty-one patients underwent transvaginal mesh excision during this time period: 17 endoscopic-assisted transvaginal and 14 transvaginal without endoscope assistance. In addition, a total of 7 patients underwent abdominal excision via laparotomy. Comparison of the 2 vaginal methods revealed no difference in the demographics or success rate, with success defined as no symptoms at follow-up. Endoscopic-assisted transvaginal excision was successful in 7 of 17 patients and transvaginal without endoscopic assistance in 9 of 13 patients (1 patient excluded for lack of follow-up data) for a total vaginal success rate of 53.3%. No intraoperative and only minor postoperative complications occurred with either vaginal method. Three patients underwent 3 vaginal attempts to achieve complete symptom resolution. The average follow-up time for the entire vaginal group was 14

Prosthetic Mesh Repair for Incarcerated Inguinal Hernia

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Cihad Tatar

2016-08-01

Full Text Available Background: Incarcerated inguinal hernia is a commonly encountered urgent surgical condition, and tension-free repair is a well-established method for the treatment of noncomplicated cases. However, due to the risk of prosthetic material-related infections, the use of mesh in the repair of strangulated or incarcerated hernia has often been subject to debate. Recent studies have demonstrated that biomaterials represent suitable materials for performing urgent hernia repair. Certain studies recommend mesh repair only for cases where no bowel resection is required; other studies, however, recommend mesh repair for patients requiring bowel resection as well. Aim: The aim of this study was to compare the outcomes of different surgical techniques performed for strangulated hernia, and to evaluate the effect of mesh use on postoperative complications. Study Design: Retrospective cross-sectional study. Methods: This retrospective study was performed with 151 patients who had been admitted to our hospital’s emergency department to undergo surgery for a diagnosis of incarcerated inguinal hernia. The patients were divided into two groups based on the applied surgical technique. Group 1 consisted of 112 patients treated with mesh-based repair techniques, while Group 2 consisted of 39 patients treated with tissue repair techniques. Patients in Group 1 were further divided into two sub-groups: one consisting of patients undergoing bowel resection (Group 3, and the other consisting of patients not undergoing bowel resection (Group 4. Results: In Group 1, it was observed that eight (7.14% of the patients had wound infections, while two (1.78% had hematomas, four (3.57% had seromas, and one (0.89% had relapse. In Group 2, one (2.56% of the patients had a wound infection, while three (7.69% had hematomas, one (2.56% had seroma, and none had relapses. There were no statistically significant differences between the two groups with respect to wound infection

A single centre comparative study of laparoscopic mesh rectopexy versus suture rectopexy

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Manash Ranjan Sahoo

2014-01-01

Full Text Available Aim: The aim of our study is to compare the results of laparoscopic mesh vs. suture rectopexy. Materials and Methods: In this retrospective study, 70 patients including both male and female of age ranging between 20 years and 65 years (mean 42.5 yrs were subjected to laparoscopic rectopexy during the period between March 2007 and June 2012, of which 38 patients underwent laparoscopic mesh rectopexy and 32 patients laparoscopic suture rectopexy. These patients were followed up for a mean period of 12 months assessing first bowel movement, hospital stay, duration of surgery, faecal incontinence, constipation, recurrence and morbidity. Results: Duration of surgery was 100.8 ± 12.4 minutes in laparoscopic suture rectopexy and 120 ± 10.8 min in laparoscopic mesh rectopexy. Postoperatively, the mean time for the first bowel movement was 38 hrs and 40 hrs, respectively, for suture and mesh rectopexy. Mean hospital stay was five (range: 4-7 days. There was no significant postoperative complication except for one port site infection in mesh rectopexy group. Patients who had varying degree of incontinence preoperatively showed improvement after surgery. Eleven out of 18 (61.1% patients who underwent laparoscopic suture rectopexy as compared to nine of 19 (47.3% patients who underwent laparoscopic mesh rectopexy improved as regards constipation after surgery. Conclusion: There were no significant difference in both groups who underwent surgery except for patients undergoing suture rectopexy had better symptomatic improvement of continence and constipation. Also, cost of mesh used in laparoscopic mesh rectopexy is absent in lap suture rectopexy group. To conclude that laparoscopic suture rectopexy is a safe and feasible procedure and have comparable results as regards operative time, morbidity, bowel function, cost and recurrence or even slightly better results than mesh rectopexy.

Notes on the Mesh Handler and Mesh Data Conversion

International Nuclear Information System (INIS)

Lee, Sang Yong; Park, Chan Eok

2009-01-01

At the outset of the development of the thermal-hydraulic code (THC), efforts have been made to utilize the recent technology of the computational fluid dynamics. Among many of them, the unstructured mesh approach was adopted to alleviate the restriction of the grid handling system. As a natural consequence, a mesh handler (MH) has been developed to manipulate the complex mesh data from the mesh generator. The mesh generator, Gambit, was chosen at the beginning of the development of the code. But a new mesh generator, Pointwise, was introduced to get more flexible mesh generation capability. An open source code, Paraview, was chosen as a post processor, which can handle unstructured as well as structured mesh data. Overall data processing system for THC is shown in Figure-1. There are various file formats to save the mesh data in the permanent storage media. A couple of dozen of file formats are found even in the above mentioned programs. A competent mesh handler should have the capability to import or export mesh data as many as possible formats. But, in reality, there are two aspects that make it difficult to achieve the competence. The first aspect to consider is the time and efforts to program the interface code. And the second aspect, which is even more difficult one, is the fact that many mesh data file formats are proprietary information. In this paper, some experience of the development of the format conversion programs will be presented. File formats involved are Gambit neutral format, Ansys-CFX grid file format, VTK legacy file format, Nastran format and CGNS

Advanced 3D Mesh Manipulation in Stereolithographic Files and Post-Print Processing for the Manufacturing of Patient-Specific Vascular Flow Phantoms.

Science.gov (United States)

O'Hara, Ryan P; Chand, Arpita; Vidiyala, Sowmya; Arechavala, Stacie M; Mitsouras, Dimitrios; Rudin, Stephen; Ionita, Ciprian N

2016-02-27

Complex vascular anatomies can cause the failure of image-guided endovascular procedures. 3D printed patient-specific vascular phantoms provide clinicians and medical device companies the ability to preemptively plan surgical treatments, test the likelihood of device success, and determine potential operative setbacks. This research aims to present advanced mesh manipulation techniques of stereolithographic (STL) files segmented from medical imaging and post-print surface optimization to match physiological vascular flow resistance. For phantom design, we developed three mesh manipulation techniques. The first method allows outlet 3D mesh manipulations to merge superfluous vessels into a single junction, decreasing the number of flow outlets and making it feasible to include smaller vessels. Next we introduced Boolean operations to eliminate the need to manually merge mesh layers and eliminate errors of mesh self-intersections that previously occurred. Finally we optimize support addition to preserve the patient anatomical geometry. For post-print surface optimization, we investigated various solutions and methods to remove support material and smooth the inner vessel surface. Solutions of chloroform, alcohol and sodium hydroxide were used to process various phantoms and hydraulic resistance was measured and compared with values reported in literature. The newly mesh manipulation methods decrease the phantom design time by 30 - 80% and allow for rapid development of accurate vascular models. We have created 3D printed vascular models with vessel diameters less than 0.5 mm. The methods presented in this work could lead to shorter design time for patient specific phantoms and better physiological simulations.

Bilateral Laparoscopic Totally Extraperitoneal Repair Without Mesh Fixation

OpenAIRE

Dehal, Ahmed; Woodward, Brandon; Johna, Samir; Yamanishi, Frank

2014-01-01

Background and Objectives: Mesh fixation during laparoscopic totally extraperitoneal repair is thought to be necessary to prevent recurrence. However, mesh fixation may increase postoperative chronic pain. This study aimed to describe the experience of a single surgeon at our institution performing this operation. Methods: We performed a retrospective review of the medical records of all patients who underwent bilateral laparoscopic totally extraperitoneal repair without mesh fixation for ing...

Mesh Plug Repair of Inguinal Hernia; Single Surgeon Experience

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Ahmet Serdar Karaca

2013-10-01

Full Text Available Aim: Mesh repair of inguinal hernia repairs are shown to be an effective and reliable method. In this study, a single surgeon%u2019s experience with plug-mesh method performs inguinal hernia repair have been reported. Material and Method: 587 patients with plug-mesh repair of inguinal hernia, preoperative age, body / mass index, comorbid disease were recorded in terms of form. All of the patients during the preoperative and postoperative hernia classification of information, duration of operation, antibiotics, perioperative complications, and later, the early and late postoperative complications, infection, recurrence rates and return to normal daily activity, verbal pain scales in terms of time and postoperative pain were evaluated. Added to this form of long-term pain ones. The presence of wound infection was assessed by the presence of purulent discharge from the incision. Visual analog scale pain status of the patients was measured. Results: 587 patients underwent repair of primary inguinal hernia mesh plug. One of the patients, 439 (74% of them have adapted follow-ups. Patients%u2019 ages ranged from 18-86. Was calculated as the mean of 47±18:07. Follow-up period of the patients was found to be a minimum of 3 months, maximum 55 months. Found an average of 28.2±13.4 months. Mean duration of surgery was 35.07±4.00 min (min:22mn-max:52mn, respectively. When complication rates of patients with recurrence in 2 patients (0.5%, hematoma development (1.4% in 6 patients, the development of infection in 11 patients (2.5% and long-term groin pain in 4 patients (0.9% appeared. Discussion: In our experience, the plug-mesh repair of primary inguinal hernia repair safe, effective low recurrence and complication rates can be used.

A Comparison of the Incidence of Early Postoperative Infections between Patients Using Synthetic Mesh and Those Undergoing Traditional Pelvic Reconstructive Surgical Procedures

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Jaromír Mašata

2013-01-01

Full Text Available New mesh-related complications such as erosion, etc., can result from abnormal postoperative healing due to surgical site infection. The aim of our study was to compare systemic inflammatory responses and the incidence of early infectious complications after reconstructive surgery using synthetic mesh and after traditional vaginal wall repair. In this prospective observational study 99 women with symptomatic pelvic organ prolapse were included; 55 women underwent traditional repair and 44 repair using mesh. After the procedure infectious complications were monitored. The patients who underwent reconstructive surgery using mesh material were more likely to have febrile morbidity in the postoperative period than the patients who had been treated with traditional repair (p=0.031; there was a higher incidence of combination febrile morbidity with elevated C-reactive protein (CRP > 50 mg/l; p=0.046, and a higher incidence of CRP increase over 30 mg/l; p=0.005. Reconstructive procedures using synthetic mesh are accompanied by a higher incidence of early post-operative infectious complications.

Laparoscopic Pelvic Floor Repair Using Polypropylene Mesh

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Shih-Shien Weng

2008-09-01

Conclusion: Laparoscopic pelvic floor repair using a single piece of polypropylene mesh combined with uterosacral ligament suspension appears to be a feasible procedure for the treatment of advanced vaginal vault prolapse and enterocele. Fewer mesh erosions and postoperative pain syndromes were seen in patients who had no previous pelvic floor reconstructive surgery.

Computational mesh generation for vascular structures with deformable surfaces

International Nuclear Information System (INIS)

Putter, S. de; Laffargue, F.; Breeuwer, M.; Vosse, F.N. van de; Gerritsen, F.A.; Philips Medical Systems, Best

2006-01-01

Computational blood flow and vessel wall mechanics simulations for vascular structures are becoming an important research tool for patient-specific surgical planning and intervention. An important step in the modelling process for patient-specific simulations is the creation of the computational mesh based on the segmented geometry. Most known solutions either require a large amount of manual processing or lead to a substantial difference between the segmented object and the actual computational domain. We have developed a chain of algorithms that lead to a closely related implementation of image segmentation with deformable models and 3D mesh generation. The resulting processing chain is very robust and leads both to an accurate geometrical representation of the vascular structure as well as high quality computational meshes. The chain of algorithms has been tested on a wide variety of shapes. A benchmark comparison of our mesh generation application with five other available meshing applications clearly indicates that the new approach outperforms the existing methods in the majority of cases. (orig.)

The use of synthetic mesh in patients undergoing ventral hernia repair during colorectal resection: Risk of infection and recurrence

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Galal H. El-Gazzaz

2012-10-01

Conclusions: Use of non-absorbable mesh during colorectal resection should be very selective. Comorbidity, duration of follow-up, emergency operations, size of area covered and infection are independent factors associated with recurrence.

Short-term outcomes of the transvaginal minimal mesh procedure for pelvic organ prolapse

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Naoko Takazawa

2018-03-01

Full Text Available Purpose: This study aimed to evaluate the clinical outcomes and complications of transvaginal minimal mesh repair without using commercially available kits for treatment of pelvic organ prolapse (POP. Materials and Methods: This retrospective cohort study involved 91 women who underwent surgical management of POP with originally designed small mesh between July 2014 and August 2015. This mesh is 56% smaller than the mesh widely used in Japan, and it has only two arms delivered into each right and left sacrospinous ligament. The main study outcome was the anatomic cure rate defined as recurrence of POP quantification (POP-Q stage II or more. We also assessed changes in the overactive bladder symptom score (OABSS and prolapse quality of life questionnaire (P-QOL and evaluated adverse events. Finally, we compared patient backgrounds between the patients with and without recurrence. Results: Prolapse recurred in 10 of 91 patients (11.0%, and all patients with recurrence were diagnosed as POP-Q stage II. As adverse events, only mesh erosion occurred in two (2.2% and pelvic pain in one (1.1% of the 91 patients. The OABSS and P-QOL were significantly improved by the operation. When we compared patient backgrounds between the patients with and without recurrence, body mass index was the only factor influencing affecting recurrence. Conclusions: Transvaginal minimal mesh repair resulted in successful outcomes with low mesh-related complications and anatomic recurrence at one year. Furthermore, significant improvement in QOL was offered by this procedure. Our minimal mesh technique should be considered as one treatment option for the management of POP.

Short-term outcomes of the transvaginal minimal mesh procedure for pelvic organ prolapse.

Science.gov (United States)

Takazawa, Naoko; Fujisaki, Akiko; Yoshimura, Yasukuni; Tsujimura, Akira; Horie, Shigeo

2018-03-01

This study aimed to evaluate the clinical outcomes and complications of transvaginal minimal mesh repair without using commercially available kits for treatment of pelvic organ prolapse (POP). This retrospective cohort study involved 91 women who underwent surgical management of POP with originally designed small mesh between July 2014 and August 2015. This mesh is 56% smaller than the mesh widely used in Japan, and it has only two arms delivered into each right and left sacrospinous ligament. The main study outcome was the anatomic cure rate defined as recurrence of POP quantification (POP-Q) stage II or more. We also assessed changes in the overactive bladder symptom score (OABSS) and prolapse quality of life questionnaire (P-QOL) and evaluated adverse events. Finally, we compared patient backgrounds between the patients with and without recurrence. Prolapse recurred in 10 of 91 patients (11.0%), and all patients with recurrence were diagnosed as POP-Q stage II. As adverse events, only mesh erosion occurred in two (2.2%) and pelvic pain in one (1.1%) of the 91 patients. The OABSS and P-QOL were significantly improved by the operation. When we compared patient backgrounds between the patients with and without recurrence, body mass index was the only factor influencing affecting recurrence. Transvaginal minimal mesh repair resulted in successful outcomes with low mesh-related complications and anatomic recurrence at one year. Furthermore, significant improvement in QOL was offered by this procedure. Our minimal mesh technique should be considered as one treatment option for the management of POP.

Laparoscopic sacrocolpopexy versus transvaginal mesh for recurrent pelvic organ prolapse.

Science.gov (United States)

Iglesia, Cheryl B; Hale, Douglass S; Lucente, Vincent R

2013-03-01

Both expert surgeons agree with the following: (1) Surgical mesh, whether placed laparoscopically or transvaginally, is indicated for pelvic floor reconstruction in cases involving recurrent advanced pelvic organ prolapse. (2) Procedural expertise and experience gained from performing a high volume of cases is fundamentally necessary. Knowledge of outcomes and complications from an individual surgeon's audit of cases is also needed when discussing the risks and benefits of procedures and alternatives. Yet controversy still exists on how best to teach new surgical techniques and optimal ways to efficiently track outcomes, including subjective and objective cure of prolapse as well as perioperative complications. A mesh registry will be useful in providing data needed for surgeons. Cost factors are also a consideration since laparoscopic and especially robotic surgical mesh procedures are generally more costly than transvaginal mesh kits when operative time, extra instrumentation and length of stay are included. Long-term outcomes, particularly for transvaginal mesh procedures, are lacking. In conclusion, all surgery poses risks; however, patients should be made aware of the pros and cons of various routes of surgery as well as the potential risks and benefits of using mesh. Surgeons should provide patients with honest information about their own experience implanting mesh and also their experience dealing with mesh-related complications.

Recurrence and Pain after Mesh Repair of Inguinal Hernias

African Journals Online (AJOL)

Abstract. Background: Surgery for inguinal hernias has ... repair. Methods: The study was conducted on all inguinal hernia patients operated between 1st. October ... bilateral (1.6%). Only 101 .... Open Mesh Versus Laparoscopic Mesh. Repair ...

Seven-year retrospective clinical study evaluating efficacy of stainless steel mesh in mandibular fractures.

Science.gov (United States)

Chakraborty, Sudip; Ghosh, Samiran; Burman, Richi; Ray, Amit

2011-10-01

The use of titanium mesh in communited mandibular fractures has been substantially documented. However, the use of stainless steel mesh for routine fixation in mandibular fractures has not been widely reported. The aim of the present study was to evaluate the efficacy of stainless steel mesh for routine osteosynthesis of mandibular fractures. A total of 252 patients who had been diagnosed with 287 single or multiple mandibular fractures at Guru Nanak Institute of Dental Science and Research from 2002 to 2009 were selected for the present study. Those with condylar fractures and other maxillofacial injuries were excluded from the study. The patients were evaluated preoperatively, intraoperatively, and postoperatively at 1 day, 6 weeks, and 3 and 6 months. The local complications, occlusion (for static function), and chewing (for dynamic function) were evaluated postoperatively. The intraoperative time taken for implant fixation (from site exposure to fixation of the last screw) was 32 minutes. Of the 252 patients, 40 (15.8%) had local complications and 24 patients required implant removal. Of the 252 patients, 82% had bilaterally satisfactory occlusion according to the surgeon at 6 months postoperatively. Discomfort in chewing unilaterally or bilaterally was reported by 17% of the patients. The results of our study have shown that stainless steel mesh has acceptable complication rates and the ability to maintain occlusion and chewing postoperatively compared with the present standards of care of mandibular fractures using miniplates. The lower cost and versatile placement of screws were the principal advantages. However, placement near the mental foramen with an extraoral approach for certain sites is the primary disadvantage. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Laser additive manufacturing of 3D meshes for optical applications.

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Essa, Khamis; Sabouri, Aydin; Butt, Haider; Basuny, Fawzia Hamed; Ghazy, Mootaz; El-Sayed, Mahmoud Ahmed

2018-01-01

Selective laser melting (SLM) is a widely used additive manufacturing process that can be used for printing of intricate three dimensional (3D) metallic structures. Here we demonstrate the fabrication of titanium alloy Ti-6Al-4V alloy based 3D meshes with nodally-connected diamond like unit cells, with lattice spacing varying from 400 to 1000 microns. A Concept Laser M2 system equipped with laser that has a wavelength of 1075 nm, a constant beam spot size of 50μm and maximum power of 400W was used to manufacture the 3D meshes. These meshes act as optical shutters / directional transmitters and display interesting optical properties. A detailed optical characterisation was carried out and it was found that these structures can be optimised to act as scalable rotational shutters with high efficiencies and as angle selective transmission screens for protection against unwanted and dangerous radiations. The efficiency of fabricated lattice structures can be increased by enlarging the meshing size.

Laser additive manufacturing of 3D meshes for optical applications.

Directory of Open Access Journals (Sweden)

Khamis Essa

Full Text Available Selective laser melting (SLM is a widely used additive manufacturing process that can be used for printing of intricate three dimensional (3D metallic structures. Here we demonstrate the fabrication of titanium alloy Ti-6Al-4V alloy based 3D meshes with nodally-connected diamond like unit cells, with lattice spacing varying from 400 to 1000 microns. A Concept Laser M2 system equipped with laser that has a wavelength of 1075 nm, a constant beam spot size of 50μm and maximum power of 400W was used to manufacture the 3D meshes. These meshes act as optical shutters / directional transmitters and display interesting optical properties. A detailed optical characterisation was carried out and it was found that these structures can be optimised to act as scalable rotational shutters with high efficiencies and as angle selective transmission screens for protection against unwanted and dangerous radiations. The efficiency of fabricated lattice structures can be increased by enlarging the meshing size.

Selective separation of oil and water with special wettability mesh membranes

KAUST Repository

Liu, Defei; Yu, Yuanlie; Chen, Xin; Zheng, Yuying

2017-01-01

that these superhydrophobic/superoleophilic or oleophobic/superhydrophilic mesh membranes are durable, stable and reusable, making them encouraging candidates for practical oil-polluted water treatment.

Worlds largest particle physics laboratory selects Proxim Wireless Mesh

CERN Multimedia

2007-01-01

"Proxim Wireless has announced that the European Organization for Nuclear Research (CERN), the world's largest particle physics laboratory and the birthplace of the World Wide Web, is using it's ORiNOCO AP-4000 mesh access points to extend the range of the laboratory's Wi-Fi network and to provide continuous monitoring of the lab's calorimeters" (1/2 page)

Tension free monofilament macropore polypropylene mesh (Gynemesh PS in female genital prolapse repair

Directory of Open Access Journals (Sweden)

Vicente Sola

2006-08-01

Full Text Available OBJECTIVES: To review intraoperative and postoperative complications associated to the correction of cystocele and rectocele with polypropylene mesh macropore monofilament (Gynemesh PS using transvaginal free tension technique. MATERIALS AND METHODS: Prospective study of patients that have been submitted to correction of cystocele and/or rectocele between November 2004 and August 2005 in the Urogynecology and Vaginal Surgery Unit of Gynecology and Obstetrics Department, Las Condes Clinic. Mesh was used in 31 patients: 9 for cystocele, 11 for rectocele, and 11 for concomitant meshes. Total mesh used 42. Media age 55 years old, weight 64 kilograms. In 7 patients we used a third mesh for correction of urinary incontinence by TVT-O technique. RESULTS: They did not present intraoperative complications, neither in immediate or delayed postoperative time. We did not observe hematoma, infection, erosion or exposition mesh. Healing of cystocele and rectocele was obtained in 100% of patients, with a pursuit between 1 and 8 months. DISCUSSION: The use of prosthetic polypropylene monofilament macropore mesh in the correction of cystocele and/or rectocele, by transvaginal route with tension free technique seems to be a safe and effective surgery procedure.

Transvaginal mesh in repair of pelvic organs prolapse as a minimally invasive surgical procedure

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Argirović Rajka

2011-01-01

Full Text Available Background/Aim. Prolapse of genital organs with or without urinary stress incontinention is the most often health problem in the elderly female population tending to increase with ageing. The aim of this study was to assess the perioperative complications and short-term outcomes of prolaps repair using transvaginal polypropylene mesh (Prolift system, Gynecare, Ethicon, USA. Methods. A retrospective study was conducted evaluating 96 women from September 2006 to January 2010 who undewent vaginal repair with implatation of a soft mesh manufactured by Gynecare, Ethicon, USA. Results. All the patients had a stage 3 or stage 4 prolapse according to the POP-Q system of ICS. Total mesh was used in 12 (13% patients isolated anterior mesh in 52 (54% patients and isolated posterior mesh in 32 (33% patients. We reported one intra-operative bladder injury and no other serious complications. At 3 months, all 96 patients were available for follow-up. Vaginal erosion occured in 9 (9.3% patients, shrinkage of mesh in 6 (6.2% patients and de novo urinary incontinence in 5 (5.2% patients. Failure rate was 6.25% (recurrent prolapse stage 3 or 4 even asymptomatic. Conclusion. Our study suggests that transvaginal polypropylene mesh applied with a tensionfree technique is a safe and effective method with low intraoperative complications and low morbidity rates. However, some complications are serious and require highly specialised management.

[Transvaginal mesh in repair of pelvic organs prolapse as a minimally invasive surgical procedure].

Science.gov (United States)

Argirović, Rajka; Berisavac, Milica; Likić-Ladević, Ivana; Kadija, Sasa; Bosković, Vladimir; Zizić, Vojislav

2011-07-01

Prolapse of genital organs with or without urinary stress incontinention is the most often health problem in the elderly female population tending to increase with ageing. The aim of this study was to assess the perioperative complications and short-term outcomes of prolaps repair using transvaginal polypropylene mesh (Prolift system, Gynecare, Ethicon, USA). A retrospective study was conducted evaluating 96 women from September 2006 to January 2010 who underwent vaginal repair with implatation of a soft mesh manufactured by Gynecare, Ethicon, USA. All the patients had a stage 3 or stage 4 prolapse according to the POP-Q system of ICS. Total mesh was used in 12 (13%) patients isolated anterior mesh in 52 (54%) patients and isolated posterior mesh in 32 (33%) patients. We reported one intra-operative bladder injury and no other serious complications. At 3 months, all 96 patients were available for follow-up. Vaginal erosion occured in 9 (9.3%) patients, shrinkage of mesh in 6 (6.2%) patients and de novo urinary incontinence in 5 (5.2%) patients. Failure rate was 6.25% (recurrent prolapse stage 3 or 4 even asymptomatic). Our study suggests that transvaginal polypropylene mesh applied with a tension-free technique is a safe and effective method with low intraoperative complications and low morbidity rates. However, some complications are serious and require highly specialised management.

Use of mesh in laparoscopic paraesophageal hernia repair

DEFF Research Database (Denmark)

Müller-Stich, Beat P.; Kenngott, Hannes G.; Gondan, Matthias

2015-01-01

Introduction. Mesh augmentation seems to reduce recurrences following laparoscopic paraesophageal hernia repair (LPHR). However, there is an uncertain risk of mesh-associated complications. Risk-benefit analysis might solve the dilemma. Materials and Methods. A systematic literature search...... potential benefits of LMAH. All data regarding LMAH were used to estimate risk of mesh-associated complications. Risk-benefit analysis was performed using a Markov Monte Carlo decision-analytic model. Results. Meta-analysis of 3 RCTs and 9 OCSs including 915 patients revealed a significantly lower...

Glue versus suture for mesh fixation in inguinal hernia repair.

Science.gov (United States)

Chandrasekar, Shruthi; Jeyakumar, S; Ganapathy, Tharun

2018-03-22

Inguinal hernia is one of the most common surgical problem presenting to the surgical OPD. Surgery is the mainstay of treatment for inguinal hernia today. Surgery for inguinal hernia has undergone a great evolution over a period of several centuries. Lichenstein's tension free hernioplasty is the one of the first surgeries taught to a surgical resident. The main aim of surgeries in this era is to give the best possible results with the least possible pain, scar and time. This has given rise to so many modifications to the classical Lichenstein's procedure and also to laparoscopic hernioplasty. Pain after inguinal hernia surgery is found to be debilitating and altering the quality of life in several patients, which has been attributed to the traumatic fixation of the mesh with sutures. This has paved way to the development of various atraumatic methods of fixation, tissue glue is one such development. Hence this study, to compare traumatic and atraumatic methods of mesh fixation in inguinal hernia repair. The aim of this study was to compare suture fixation versus tissue glue fixation of the mesh in inguinal hernia repair. Primary objective was to compare the immediate and chronic post-operative pain. Secondary objective was to compare the time taken for the procedure by the two methods in use and also to compare the presence of any complications. and methodology: This study was done in the General Surgery department of XXX hospital, medical college and research centre, kattangulathur after Ethics committee clearance. It is a single blinded study. The study was done on 51 patients consenting for the study and meeting the inclusion criterias from the period of March 2016 to August 2017 out of which 26 were selected for glue mesh fixation and 25 for suture mesh fixation according to simple randomization. The suture group patients underwent classical Lichenstein's tension free hernioplasty and the glue group underwent Lichenstein's hernioplasty with glue where dots of

Evidence to justify retention of transvaginal mesh: comparison between laparoscopic sacral colpopexy and transvaginal Elevate™ mesh.

Science.gov (United States)

To, Valérie; Hengrasmee, Pattaya; Lam, Alan; Luscombe, Georgina; Lawless, Anna; Lam, Justin

2017-12-01

To determine if laparoscopic sacral colpopexy (LSC) offers better apical support with a lower exposure rate than transvaginal mesh surgery with Elevate™. This was a retrospective cohort study comparing patients with apical prolapse (POP-Q point C ≥ -1) who underwent Elevate™ mesh repair (n = 146) with patients who underwent laparoscopic sacral colpopexy (n = 267). The sacral colpopexy group had a mean age of 59 years and a BMI of 25.7. Patients in the Elevate™ group were older, with a mean age of 63 and a BMI of 26.3. Most of the patients of both groups presented with pelvic organ prolapse stage III (LSC 73.8% and Elevate™ 87.0%) and their mean POP-Q point C were not significantly different (LSC 1.4 vs Elevate™ 1.2 cm). Operative time was longer in the LSC group (113 vs 91 min, p < 0.001), but estimated blood loss was lower (75 cm 3 vs 137 cm 3 , p < 0.001). No difference in mesh exposure rate could be found between the two groups at one year (Elevate™ 0.7% vs LSC 2.6%, OR 0.26, 95% CI 0.03 to 2.10, p = 0.21). One-year objective cure rate, defined as no descent beyond the hymen, was 97.0% in the LSC group and 96.6% in the Elevate™ group (p = .81). The overall recurrence (objective, subjective recurrence or reoperation) was also not different between the groups (LSC 4.5% vs Elevate 4.8%, p = 0.89). Transvaginal Elevate™ mesh delivers comparable apical support with a low exposure rate similar to that of laparoscopic sacral colpopexy.

Prevention of parastomal hernia with a preperitoneal polypropelene mesh.

Science.gov (United States)

Valdés-Hernández, Javier; Díaz Milanés, Juan Antonio; Capitán Morales, Luis Cristóbal; Del Río la Fuente, Francisco Javier; Torres Arcos, Cristina; Cañete Gómez, Jesús; Oliva Mompeán, Fernando; Padillo Ruiz, Javier

2015-01-01

To show our results with the use of a polypropylene mesh at the stoma site, as prophylaxis of parastomal hernias in patients with rectal cancer when a terminal colostomy is performed. From January 2010 until March 2014, 45 consecutive patients with rectal cancer, underwent surgical treatment with the need of a terminal colostomy. A prophylactic mesh was placed in a sublay position at the stoma site in all cases. We analyze Demographics, technical issues and effectiveness of the procedure, as well as subsequent complications. A prophylactic mesh was placed in 45 patients, 35 male and 10 females, mean age of 66.2 (47-88) and Body Mass Index 29.19 (20.4-40.6). A total of 7 middle rectal carcinoma, 36 low rectal carcinoma, one rectal melanoma and one squamous cell anal carcinoma were electively treated with identical protocol. Abdominoperineal resection was performed in 38 patients, and low anterior resection with terminal colostomy in 7. An open approach was elected in 39 patients and laparoscopy in 6, with 2 conversions to open surgery. Medium follow up was 22 months (2.1-53). Overall, 3 parastomal hernias (6.66%) were found, one of which was a radiological finding with no clinical significance. No complications related to the mesh or the colostomy were found. The use of a prophylactic polypropylene mesh placed in a sublay position at the stoma site is a safe and feasible technique. It lowers the incidence of parastomal hernias with no increased morbidity. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Lichtenstein Mesh Repair (LMR) v/s Modified Bassini's Repair (MBR) + Lichtenstein Mesh Repair of Direct Inguinal Hernias in Rural Population - A Comparative Study.

Science.gov (United States)

Patil, Santosh M; Gurujala, Avinash; Kumar, Ashok; Kumar, Kuthadi Sravan; Mithun, Gorre

2016-02-01

Lichtenstein's tension free mesh hernioplasty is the commonly done open technique for inguinal hernias. As our hospital is in rural area, majority of patients are labourers, open hernias are commonly done. The present study was done by comparing Lichtenstein Mesh Repair (LMR) v/s Modified Bassini's repair (MBR) + Lichtenstein mesh repair (LMR) of direct Inguinal Hernias to compare the technique of both surgeries and its outcome like postoperative complications and recurrence rate. A comparative randomized study was conducted on patients reporting to MNR hospital, sangareddy with direct inguinal hernias. A total of fifty consecutive patients were included in this study of which, 25 patients were operated by LMR and 25 patients were operated by MBR+LMR and followed up for a period of two years. The outcomes of the both techniques were compared. Study involved 25 each of Lichtenstein's mesh repair (LMR) and modified bassini's repair (MBR) + LMR, over a period of 2 years. The duration of surgery for lichtenstein mesh repair is around 34.56 min compared to LMR+MBR, which is 47.56 min which was statistically significant (p-value is MBR group in POD 1, but not statistically significant (p-value is 0.0949) and from POD 7 the pain was almost similar in both groups. The recurrence rate is 2% for LMR and 0% for MBR+LMR. LMR+MBR was comparatively better than only LMR in all direct inguinal hernias because of low recurrence rate (0%) and low postoperative complications, which showed in our present study.

Comparison of Absorbable Mesh Plate versus Titanium-Dynamic Mesh Plate in Reconstruction of Blow-Out Fracture: An Analysis of Long-Term Outcomes

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Woon Il Baek

2014-07-01

Full Text Available Background A blow-out fracture is one of the most common facial injuries in midface trauma. Orbital wall reconstruction is extremely important because it can cause various functional and aesthetic sequelae. Although many materials are available, there are no uniformly accepted guidelines regarding material selection for orbital wall reconstruction. Methods From January 2007 to August 2012, a total of 78 patients with blow-out fractures were analyzed. 36 patients received absorbable mesh plates, and 42 patients received titanium-dynamic mesh plates. Both groups were retrospectively evaluated for therapeutic efficacy and safety according to the incidence of three different complications: enophthalmos, extraocular movement impairment, and diplopia. Results For all groups (inferior wall fracture group, medial wall fractrue group, and combined inferomedial wall fracture group, there were improvements in the incidence of each complication regardless of implant types. Moreover, a significant improvement of enophthalmos occurred for both types of implants in group 1 (inferior wall fracture group. However, we found no statistically significant differences of efficacy or complication rate in every groups between both implant types. Conclusions Both types of implants showed good results without significant differences in long-term follow up, even though we expected the higher recurrent enophthalmos rate in patients with absorbable plate. In conclusion, both types seem to be equally effective and safe for orbital wall reconstruction. In particular, both implant types significantly improve the incidence of enophthalmos in cases of inferior orbital wall fractures.

Tensile Behaviour of Welded Wire Mesh and Hexagonal Metal Mesh for Ferrocement Application

Science.gov (United States)

Tanawade, A. G.; Modhera, C. D.

2017-08-01

Tension tests were conducted on welded mesh and hexagonal Metal mesh. Welded Mesh is available in the market in different sizes. The two types are analysed viz. Ø 2.3 mm and Ø 2.7 mm welded mesh, having opening size 31.75 mm × 31.75 mm and 25.4 mm × 25.4 mm respectively. Tensile strength test was performed on samples of welded mesh in three different orientations namely 0°, 30° and 45° degrees with the loading axis and hexagonal Metal mesh of Ø 0.7 mm, having opening 19.05 × 19.05 mm. Experimental tests were conducted on samples of these meshes. The objective of this study was to investigate the behaviour of the welded mesh and hexagonal Metal mesh. The result shows that the tension load carrying capacity of welded mesh of Ø 2.7 mm of 0° orientation is good as compared to Ø2.3 mm mesh and ductility of hexagonal Metal mesh is good in behaviour.

No. 351-Transvaginal Mesh Procedures for Pelvic Organ Prolapse.

Science.gov (United States)

Larouche, Maryse; Geoffrion, Roxana; Walter, Jens-Erik

2017-11-01

publications with study groups larger than 20 individuals were selected because this criterion was used in the largest meta-analysis referenced in this guideline. A total of 1470 studies were obtained; after selecting only applicable studies and excluding duplicates, 68 manuscripts were reviewed and included. The content and recommendations were drafted and agreed upon by the principal authors and members of the Urogynaecology Committee. The Board of the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development and Evaluation methodology framework. The Summary of Findings is available upon request. It is expected that this guideline will benefit women with pelvic organ prolapse by ensuring that health care providers are aware of outcomes related to transvaginal mesh procedures and steps in the management of related complications. This should guide patient-informed consent before such procedures are undertaken. The benefits clearly outweigh the potential harms or costs of implementation of this guideline, although no direct harms or costs are identified. Evidence will be reviewed 5 years after publication to decide whether all or part of the guideline should be updated. However, if important new evidence is published prior to the 5-year cycle, the review process may be accelerated for a more rapid update of some recommendations. RECOMMENDATIONS. Copyright © 2017 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.

3D active shape models of human brain structures: application to patient-specific mesh generation

Science.gov (United States)

Ravikumar, Nishant; Castro-Mateos, Isaac; Pozo, Jose M.; Frangi, Alejandro F.; Taylor, Zeike A.

2015-03-01

The use of biomechanics-based numerical simulations has attracted growing interest in recent years for computer-aided diagnosis and treatment planning. With this in mind, a method for automatic mesh generation of brain structures of interest, using statistical models of shape (SSM) and appearance (SAM), for personalised computational modelling is presented. SSMs are constructed as point distribution models (PDMs) while SAMs are trained using intensity profiles sampled from a training set of T1-weighted magnetic resonance images. The brain structures of interest are, the cortical surface (cerebrum, cerebellum & brainstem), lateral ventricles and falx-cerebri membrane. Two methods for establishing correspondences across the training set of shapes are investigated and compared (based on SSM quality): the Coherent Point Drift (CPD) point-set registration method and B-spline mesh-to-mesh registration method. The MNI-305 (Montreal Neurological Institute) average brain atlas is used to generate the template mesh, which is deformed and registered to each training case, to establish correspondence over the training set of shapes. 18 healthy patients' T1-weightedMRimages form the training set used to generate the SSM and SAM. Both model-training and model-fitting are performed over multiple brain structures simultaneously. Compactness and generalisation errors of the BSpline-SSM and CPD-SSM are evaluated and used to quantitatively compare the SSMs. Leave-one-out cross validation is used to evaluate SSM quality in terms of these measures. The mesh-based SSM is found to generalise better and is more compact, relative to the CPD-based SSM. Quality of the best-fit model instance from the trained SSMs, to test cases are evaluated using the Hausdorff distance (HD) and mean absolute surface distance (MASD) metrics.

Clinical outcomes after parastomal hernia repair with a polyester monofilament composite mesh

DEFF Research Database (Denmark)

Oma, E; Pilsgaard, B; Jorgensen, L N

2018-01-01

with intraperitoneal placement of a polyester monofilament macroporous composite mesh. METHODS: Data on all patients undergoing parastomal hernia repair with Parietex™ Composite Parastomal Mesh at our institution during a 4-year period were examined. Patients with urostomy were excluded. A team of three experienced...... chronic pain. CONCLUSION: In this study, we found low rates of recurrence and chronic pain following parastomal hernia repair using intraperitoneal reinforcement with a polyester monofilament composite mesh....

Transvaginal mesh kits--how "serious" are the complications and are they reversible?

Science.gov (United States)

Lee, Dominic; Dillon, Benjamin; Lemack, Gary; Gomelsky, Alex; Zimmern, Philippe

2013-01-01

To review the merit of the U.S. Food and Drug Administration-issued warnings on the use of transvaginal mesh in women with pelvic organ prolapse because of escalating complications. On institutional review board approval, we reviewed the data from 2 tertiary institutions managing complications of transvaginal mesh. The data recorded included mesh type, details of surgical removal, and patient-reported clinical outcomes. From 2006 to March 2011, 58 women were evaluated. Their mean age was 54.6 years (range 32-80), with a mean follow-up of 13 months (range 6-67). The mean interval to mesh excision surgery from the original prolapse surgery was 21 months (range 2-60). Of the 58 women, 35 (60%) had undergone concurrent midurethral sling surgery with the transvaginal mesh surgery. Also, 21 of the 58 patients (36%) had undergone initial mesh removal attempts before their referral to either tertiary institution. Most women presented with multiple complaints, with mesh extrusion the most frequently reported (n=43 [74%]). Of the 58 women, 17 (29%) required re-excision of residual mesh, 13 once and 4 twice. Five women developed recurrent symptomatic pelvic organ prolapse (7%). The residual rate of dyspareunia and pelvic pain was 14% and 22%, respectively. Fourteen women (24%) were treated successfully, with complete resolution of all presenting symptoms. As outlined in the Food and Drug Administration notifications, patients should be forewarned that some transvaginal mesh complications are life altering and might not always be surgically correctable. Copyright © 2013 Elsevier Inc. All rights reserved.

Conforming to interface structured adaptive mesh refinement: 3D algorithm and implementation

Science.gov (United States)

Nagarajan, Anand; Soghrati, Soheil

2018-03-01

A new non-iterative mesh generation algorithm named conforming to interface structured adaptive mesh refinement (CISAMR) is introduced for creating 3D finite element models of problems with complex geometries. CISAMR transforms a structured mesh composed of tetrahedral elements into a conforming mesh with low element aspect ratios. The construction of the mesh begins with the structured adaptive mesh refinement of elements in the vicinity of material interfaces. An r-adaptivity algorithm is then employed to relocate selected nodes of nonconforming elements, followed by face-swapping a small fraction of them to eliminate tetrahedrons with high aspect ratios. The final conforming mesh is constructed by sub-tetrahedralizing remaining nonconforming elements, as well as tetrahedrons with hanging nodes. In addition to studying the convergence and analyzing element-wise errors in meshes generated using CISAMR, several example problems are presented to show the ability of this method for modeling 3D problems with intricate morphologies.

Objective and subjective outcome 3 years after synthetic transobturator nonabsorbable anterior mesh use in symptomatic advanced pelvic organ prolapse surgery

Directory of Open Access Journals (Sweden)

Tsia-Shu Lo

2015-05-01

Conclusion: The Perigee System gave a favorable result in both anatomical and subjective success rates with a low rate of mesh-related morbidities. The strength of the study reported here is its long-term follow up of a relatively large number of patients and the use of validated questionnaires. Limitations are that it is not a RCT; hence, selection and indication bias is unavoidable. The favorable outcome and low morbidities resulting from mesh use is from a single surgeon's perspective and may not be generalized to others.

Biological Mesh Implants for Abdominal Hernia Repair: US Food and Drug Administration Approval Process and Systematic Review of Its Efficacy.

Science.gov (United States)

Huerta, Sergio; Varshney, Anubodh; Patel, Prachi M; Mayo, Helen G; Livingston, Edward H

2016-04-01

Expensive biological mesh materials are increasingly used to reinforce abdominal wall hernia repairs. The clinical and cost benefit of these materials are unknown. To review the published evidence on the use of biological mesh materials and to examine the US Food and Drug Administration (FDA) approval history for these devices. Search of multiple electronic databases (Ovid, MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, and Cochrane National Health Service Economic Evaluation Database) to identify articles published between 1948 and June 30, 2015, on the use of biological mesh materials used to reinforce abdominal wall hernia repair. Keywords searched included surgical mesh, abdominal hernia, recurrence, infection, fistula, bioprosthesis, biocompatible materials, absorbable implants, dermis, and collagen. The FDA online database for 510(k) clearances was reviewed for all commercially available biological mesh materials. The median national price for mesh materials was established by a benchmarking query through several Integrated Delivery Network and Group Purchasing Organization tools. Of 274 screened articles, 20 met the search criteria. Most were case series that reported results of convenience samples of patients at single institutions with a variety of clinical problems. Only 3 of the 20 were comparative studies. There were no randomized clinical trials. In total, outcomes for 1033 patients were described. Studies varied widely in follow-up time, operative technique, meshes used, and patient selection criteria. Reported outcomes and clinical outcomes, such as fistula formation and infection, were inconsistently reported across studies. Conflicts of interest were not reported in 16 of the 20 studies. Recurrence rates ranged from 0% to 80%. All biological mesh devices were approved by the FDA based on substantial equivalence to a group of nonbiological predicate

Complications of transvaginal silicone-coated polyester synthetic mesh sling.

Science.gov (United States)

Govier, F E; Kobashi, K C; Kuznetsov, D D; Comiter, C; Jones, P; Dakil, S E; James, R

2005-10-01

To report a premarket multicenter trial to test the feasibility of a transvaginal silicone-coated polyester synthetic mesh sling in women with anatomic incontinence. Fifty-one patients in four centers underwent transvaginal placement of a silicone-coated polyester synthetic mesh sling (American Medical Systems) during an 8-month period. Of the 51 patients, 31 were part of a prospective institutional review board-approved feasibility trial in three centers funded by American Medical Systems (group 1) and 20 underwent implantation by a single surgeon and their data were retrospectively reviewed (group 2). The studies were done concomitantly, and all slings were fixed transvaginally with bone anchors. All patients in group 1 were followed up at 4 weeks, 6 months, and 1 year (as applicable) with repeat questionnaires, physical examinations, and pad tests. In group 1, 20 patients completed 6 months of follow-up. Ten patients (32%) required a second surgical procedure at an average of 183 days (range 68 to 343) postoperatively. Eight patients (26%) had vaginal extrusion of the mesh, one (3%) required sling lysis, and one (3%) required sling removal because of infection. In group 2, 8 patients (40%) underwent sling removal for vaginal extrusion at a mean of 160 days (range 83 to 214). Transvaginally placed silicone-coated mesh slings used for the treatment of urinary incontinence demonstrated an unacceptably high vaginal extrusion rate in this study. Once identified, this study was immediately terminated, and this product was not marketed for this application in the United States.

Challenging the Myth: Transvaginal Mesh is Not Associated with Carcinogenesis.

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Chughtai, Bilal; Sedrakyan, Art; Mao, Jialin; Thomas, Dominique; Eilber, Karyn S; Clemens, J Quentin; Anger, Jennifer T

2017-10-01

We sought to determine if there was a potential link between synthetic polypropylene mesh implantation for transvaginal pelvic organ prolapse and stress urinary incontinence, and carcinogenesis using statewide administrative data. Women who underwent transvaginal surgery for pelvic organ prolapse or stress urinary incontinence with mesh between January 2008 and December 2009 in New York State were identified using ICD-9-CM procedure codes and CPT-4 codes. Patients in the mesh cohort were individually matched to 2 control cohorts based on comorbidities and procedure date. Carcinogenesis was determined before and after matching at 1, 2 and 3 years, and during the entire followup time. A total of 2,229 patients who underwent mesh based pelvic organ prolapse surgery and 10,401 who underwent sling surgery for stress urinary incontinence between January 2008 and December 2009 were included in the study. Mean followup was 6 years (range 5 to 7). Exact matching between the mesh and control cohorts resulted in 1,870 pairs for pelvic organ prolapse mesh and cholecystectomy (1:2), 1,278 pairs for pelvic organ prolapse mesh and hysterectomy (1:1), 7,986 pairs for sling and cholecystectomy (1:1) and 3,810 pairs for sling and hysterectomy (1:1). Transvaginal mesh implantation was not associated with an increased risk of a cancer diagnosis (pelvic/local cancers or any cancer) at 1 year and during the entire followup of up to 7 years. Transvaginal surgery with implantation of mesh was not associated with the development of malignancy at a mean followup of 6 years. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Laparoscopy-like operative vaginoscopy: a new approach to manage mesh erosions.

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Billone, Valentina; Amorim-Costa, Célia; Campos, Sara; Rabischong, Benoĭt; Bourdel, Nicolas; Canis, Michel; Botchorishvili, Revaz

2015-01-01

Mesh erosion through the vagina is the most common complication of synthetic mesh used for pelvic organ prolapse repair. However, conventional transvaginal mesh excision has many technical limitations. We aimed at creating and describing a new surgical technique for transvaginal removal of exposed mesh that would enable better exposition and access, thus facilitating optimal treatment. A step-by-step video showing the technique. A university tertiary care hospital. Five patients previously submitted to pelvic organ prolapse repair using synthetic mesh, presenting mesh erosion through the vagina. Mesh excision using a laparoscopy-like operative vaginoscopy in which standard laparoscopic instruments are used through a single-incision laparoscopic surgery port device placed in the vagina. In all cases, a very good exposure of the mesh was achieved, a minimal tissue traction was required, and the procedures were performed in a very ergonomic way. All the patients were discharged on the same day of the surgery and had a painless postoperative course. So far, there have been no cases of relapse. This seems to be a simple, cheap, and valuable minimally invasive technique with many advantages in comparison with the conventional approach. More cases and time are necessary to access its long-term efficacy. It may possibly be used for the management of other conditions. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

Lichtenstein Mesh Repair (LMR) v/s Modified Bassini’s Repair (MBR) + Lichtenstein Mesh Repair of Direct Inguinal Hernias in Rural Population – A Comparative Study

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Patil, Santosh M; Kumar, Ashok; Kumar, Kuthadi Sravan; Mithun, Gorre

2016-01-01

Introduction Lichtenstein’s tension free mesh hernioplasty is the commonly done open technique for inguinal hernias. As our hospital is in rural area, majority of patients are labourers, open hernias are commonly done. The present study was done by comparing Lichtenstein Mesh Repair (LMR) v/s Modified Bassini’s repair (MBR) + Lichtenstein mesh repair (LMR) of direct Inguinal Hernias to compare the technique of both surgeries and its outcome like postoperative complications and recurrence rate. Materials and Methods A comparative randomized study was conducted on patients reporting to MNR hospital, sangareddy with direct inguinal hernias. A total of fifty consecutive patients were included in this study of which, 25 patients were operated by LMR and 25 patients were operated by MBR+LMR and followed up for a period of two years. The outcomes of the both techniques were compared. Results Study involved 25 each of Lichtenstein’s mesh repair (LMR) and modified bassini’s repair (MBR) + LMR, over a period of 2 years. The duration of surgery for lichtenstein mesh repair is around 34.56 min compared to LMR+MBR, which is 47.56 min which was statistically significant (p-value is MBR group in POD 1, but not statistically significant (p-value is 0.0949) and from POD 7 the pain was almost similar in both groups. The recurrence rate is 2% for LMR and 0% for MBR+LMR. Conclusion LMR+MBR was comparatively better than only LMR in all direct inguinal hernias because of low recurrence rate (0%) and low postoperative complications, which showed in our present study. PMID:27042517

Urogynecologic Surgical Mesh Implants

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... procedures performed to treat pelvic floor disorders with surgical mesh: Transvaginal mesh to treat POP Transabdominal mesh to treat ... address safety risks Final Order for Reclassification of Surgical Mesh for Transvaginal Pelvic Organ Prolapse Repair Final Order for Effective ...

Intravesical midurethral sling mesh erosion secondary to transvaginal mesh reconstructive surgery

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Sukanda Bin Jaili

2015-05-01

Conclusion: Repeated vaginal reconstructive surgery may jeopardize a primary mesh or sling, and pose a high risk of mesh erosion, which may be delayed for several years. Removal of the mesh erosion and bladder repair are feasible pervaginally with good outcome.

A THREE-YEAR EXPERIENCE WITH ANTERIOR TRANSOBTURATOR MESH (ATOM AND POSTERIOR ISCHIORECTAL MESH (PIRM

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Marijan Lužnik

2018-02-01

Full Text Available Background. Use of alloplastic mesh implantates allow a new urogynecologycal surgical techniques achieve a marked improvement in pelvic organ static and pelvic floor function with minimally invasive needle transvaginal intervention like an anterior transobturator mesh (ATOM and a posterior ischiorectal mesh (PIRM procedures. Methods. In three years, between April 2006 and May 2009, we performed one hundred and eightyfour operative corrections of female pelvic organ prolapse (POP and pelvic floor dysfunction (PFD with mesh implantates. The eighty-three patients with surgical procedure TVT-O or Monarc as solo intervention indicated by stress urinary incontinence without POP, are not included in this number. In 97 % of mesh operations, Gynemesh 10 × 15 cm was used. For correction of anterior vaginal prolapse with ATOM procedure, Gynemesh was individually trimmed in mesh with 6 free arms for tension-free transobturator application and tension-free apical collar. IVS (Intravaginal sling 04 Tunneller (Tyco needle system was used for transobturator application of 6 arms through 4 dermal incisions (2 on right and 2 on left. Minimal anterior median colpotomy was made in two separate parts. For correction of posterior vaginal prolapse with PIRM procedure Gynemesh was trimmed in mesh with 4 free arms and tension-free collar. Two ischiorectal long arms for tension-free application through fossa ischiorectale – right and left, and two short arms for perineal body also on both sides. IVS 02 Tunneller (Tyco needle system was used for tension-free application of 4 arms through 4 dermal incisions (2 on right and 2 on left in PIRM. Results. All 184 procedures were performed relatively safely. In 9 cases of ATOM we had perforation of bladder, in 5 by application of anterior needle, in 3 by application of posterior needle and in one case with pincette when collar was inserted in lateral vesico – vaginal space. In 2 cases of PIRM we had perforation of rectum

[Implants for genital prolapse : Contra mesh surgery].

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Hampel, C

2017-12-01

Alloplastic transvaginal meshes have become very popular in the surgery of pelvic organ prolapse (POP) as did alloplastic suburethral slings in female stress incontinence surgery, but without adequate supporting data. The simplicity of the mesh procedure facilitates its propagation with acceptance of higher revision and complication rates. Since attending physicians do more and more prolapse surgeries without practicing or teaching alternative techniques, expertise in these alternatives, which might be very useful in cases of recurrence, persistence or complications, is permanently lost. It is doubtful that proper and detailed information about alternatives, risks, and benefits of transvaginal alloplastic meshes is provided to every single prolapse patient according to the recommendations of the German POP guidelines, since the number of implanted meshes exceeds the number of properly indicated mesh candidates by far. Although there is no dissent internationally about the available mesh data, thousands of lawsuits in the USA, insolvency of companies due to claims for compensation and unambiguous warnings from foreign urological societies leave German urogynecologists still unimpressed. The existing literature in pelvic organ prolapse exclusively focusses on POP stage and improvement of that stage with surgical therapy. Instead, typical prolapse symptoms should trigger therapy and improvement of these symptoms should be the utmost treatment goal. It is strongly recommended for liability reasons to obtain specific written informed consent.

Anterior six arms prolene mesh for high stage vaginal prolapse: five years follow-up

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Luis Gustavo M. de Toledo

Full Text Available ABSTRACT Introduction In high stage vaginal prolapse, recurrence risk patients, anterior and apical defects need to be addressed in the same procedure. The pre-molded commercial mesh kits are expensive and not always available. Alternative effective and safe treatment ways, with lower costs are desirable. Objective To present long term follow-up of patients treated with a homemade mesh shape to correct high stage prolapses. Materials and Methods We describe prospectively 18 patients with anterior and apical vaginal prolapses, stages III and IV, repaired using this specific design of mesh. All patients were submitted to pre-operative clinical evaluation and urodynamics. Prolapse was classified using the pelvic organ prolapse quantification (POP-Q. Intervention Prolapse surgery, using a six arms prolene mesh, through a single anterior vaginal incision. Outcome Measurements: POP-Q, patients satisfaction, descriptive statistical analysis. Results Between February 2009 and Oct 2010, 18 consecutive women underwent the above-mentioned surgery. Mean age was 68 years. At a mean follow-up of .,4 years (5 to 5.8 years, 16 (89% patients were continent, mean Ba point came from +4.7cm to - 2.5cm, mean C point from +2.8cm to -6.6cm and mean Bp point from +1.3 to -1.7cm. There were two (11% objective failures, but all the patients were considered success subjectively. There were two cases of mesh vaginal extrusion. Conclusions The homemade six arms prolene mesh allows concomitant correction of anterior and apical prolapses, through a single anterior vaginal incision, being an effective, safe and affordable treatment option when mesh is needed.

Treatment of Mesh Skin Grafted Scars Using a Plasma Skin Regeneration System

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Takamitsu Higashimori

2010-01-01

Full Text Available Objectives. Several modalities have been advocated to treat traumatic scars, including surgical techniques and laser resurfacing. Recently, a plasma skin regeneration (PSR system has been investigated. There are no reports on plasma treatment of mesh skin grafted scars. The objective of our study is to evaluate the effectiveness and complications of plasma treatment of mesh skin grafted scars in Asian patients. Materials and Methods. Four Asian patients with mesh skin grafted scars were enrolled in the study. The plasma treatments were performed at monthly intervals with PSR, using energy settings of 3 to 4 J. Improvement was determined by patient questionnaires and physician evaluation of digital photographs taken prior to treatment and at 3 months post treatment. The patients were also evaluated for any side effects from the treatment. Results. All patients showed more than 50% improvement. The average pain score on a 10-point scale was 6.9 +/− 1.2 SD and all patients tolerated the treatments. Temporary, localized hypopigmentation was observed in two patients. Hyperpigmentation and worsening of scarring were not observed. Conclusions. Plasma treatment is clinically effective and is associated with minimal complications when used to treat mesh skin grafted scars in Asian patients.

Polygonal Prism Mesh in the Viscous Layers for the Polyhedral Mesh Generator, PolyGen

International Nuclear Information System (INIS)

Lee, Sang Yong; Park, Chan Eok; Kim, Shin Whan

2015-01-01

Polyhedral mesh has been known to have some benefits over the tetrahedral mesh. Efforts have been made to set up a polyhedral mesh generation system with open source programs SALOME and TetGen. The evaluation has shown that the polyhedral mesh generation system is promising. But it is necessary to extend the capability of the system to handle the viscous layers to be a generalized mesh generator. A brief review to the previous works on the mesh generation for the viscous layers will be made in section 2. Several challenging issues for the polygonal prism mesh generation will be discussed as well. The procedure to generate a polygonal prism mesh will be discussed in detail in section 3. Conclusion will be followed in section 4. A procedure to generate meshes in the viscous layers with PolyGen has been successfully designed. But more efforts have to be exercised to find the best way for the generating meshes for viscous layers. Using the extrusion direction of the STL data will the first of the trials in the near future

Surgeon Experience and Complications of Transvaginal Prolapse Mesh.

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Kelly, Erin C; Winick-Ng, Jennifer; Welk, Blayne

2016-07-01

To measure the proportion of women with transvaginal prolapse mesh complications and their association with surgeon volume. We conducted a retrospective, population-based cohort study of all women who underwent a mesh-based prolapse procedure using administrative data (hospital procedure and physician billing records) between 2002 and 2013 in Ontario, Canada. The primary outcome was surgical revision of the mesh. Primary exposure was surgeon volume: high (greater than the 75th percentile, requiring a median of five [interquartile range 5-6] procedures per year) and very high (greater than the 90th percentile, requiring a median of 13 [interquartile range 11-14] procedures per year) volume mesh implanters were identified each year. Primary analysis was an adjusted Cox proportional hazards model. A total of 5,488 women underwent mesh implantation by 1 of 368 unique surgeons. Median follow-up time was 5.4 (interquartile range 3.0-8.0) years. We found that 218 women (4.0%) underwent mesh reoperation a median of 1.17 (interquartile range 0.58-2.90) years after implantation. The hazard of reoperation for complications was only lower for patients of very high-volume surgeons (3.0% [145/3,001] compared with 4.8% [73/2,447], adjusted hazards ratio 0.59, 95% confidence interval 0.40-0.86). In multivariable modeling, younger age, concomitant hysterectomy, blood transfusion, and increased medical comorbidity were all associated with vaginal mesh reoperation. Approximately 5% of women who underwent mesh-based prolapse surgery required reoperation for a mesh complication within 10 years. The risk of reoperation was lowest for surgeons performing 14 or more procedures per year.

Assessment of Pain and Quality of Life in Lichtenstein Hernia Repair Using a New Monofilament PTFE Mesh: Comparison of Suture vs. Fibrin-Sealant Mesh Fixation.

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Fortelny, René H; Petter-Puchner, Alexander H; Redl, Heinz; May, Christopher; Pospischil, Wolfgang; Glaser, Karl

2014-01-01

Inguinal hernia repair is one of the most common operations in general surgery. The Lichtenstein tension-free operation has become the gold standard in open inguinal hernia repair. Despite the low recurrence rates, pain and discomfort remain a problem for a large number of patients. The aim of this study was to compare suture fixation vs. fibrin sealing by using a new monofilament PTFE mesh, i.e., the Infinit(®) mesh by W. L. Gore & Associates. This study was designed as a controlled prospective single-center two-cohort study. A total of 38 patients were enrolled and operated in Lichtenstein technique either standard suture mesh fixation or fibrin-sealant mesh fixation were used as described in the TIMELI trial. Primary outcome parameters were postoperative complications with the new mesh (i.e., seroma, infection), pain, and quality of life evaluated by the VAS and the SF-36 questionnaire. Secondary outcome was recurrence assessed by ultrasound and physical examination. Follow-up time was 1 year. Significantly, less postoperative pain was reported in the fibrin-sealant group compared to the suture group at 6 weeks (P = 0.035), 6 months (P = 0.023), and 1 year (P = 0.011) postoperatively. Additionally, trends toward a higher postoperative quality of life, a faster surgical procedure, and a shorter hospital stay were seen in the fibrin-sealant group. Fibrin-sealant mesh fixation in Lichtenstein hernioplasty effectively reduces acute and chronic postoperative pain. Monofilament, macro-porous, knitted PTFE meshes seem to be a practicable alternative to commonly used polypropylene meshes in open inguinal hernia repair.

Assessment of pain and quality of life in Lichtenstein hernia repair using a new monofilament PTFE mesh: comparison of suture vs. fibrin sealant mesh fixation

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René H Fortelny

2014-11-01

Full Text Available Background: Inguinal hernia repair is one of the most common operations in general surgery. The Lichtenstein tension-free operation has become the gold standard in open inguinal hernia repair. Despite the low recurrence rates, pain and discomfort remain a problem for a large number of patients. The aim of this study was to compare suture fixation vs. fibrin sealing by using a new monofilament PTFE mesh, i.e. the Infinit® mesh by W. L. Gore & Associates. Methods: This study was designed as a controlled prospective single-centre two cohort study. A total of 38 patients were enrolled and operated in Lichtenstein technique either standard suture mesh fixation or fibrin sealant mesh fixation were used as described in the TIMELI trial. Primary outcome parameters were postoperative complications with the new mesh (i.e. seroma, infection, pain and quality of life evaluated by the VAS and the SF-36 questionnaire. Secondary outcome was recurrence assessed by ultrasound and physical examination. Follow-up time was 1 year.Results: Significantly less postoperative pain was reported in the fibrin sealant group compared to the suture group at 6 weeks (P=0.035, 6 months (P=0.023 and 1 year (P=0.011 postoperatively. Additionally trends towards a higher postoperative quality of life, a faster surgical procedure and a shorter hospital stay were seen in the fibrin sealant group.Conclusion: Fibrin sealant mesh fixation in Lichtenstein hernioplasty effectively reduces acute and chronic postoperative pain. Monofilament, macro-porous, knitted PTFE meshes seem to be a practicable alternative to commonly used polypropylene meshes in open inguinal hernia repair.

Postoperative Urinary Retention and Urinary Tract Infections Predict Midurethral Sling Mesh Complications.

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Punjani, Nahid; Winick-Ng, Jennifer; Welk, Blayne

2017-01-01

To determine if postoperative urinary retention and urinary tract infections (UTIs) were predictors of future mesh complications requiring surgical intervention after midurethral sling (MUS). Administrative data in Ontario, Canada, between 2002 and 2013 were used to identify all women who underwent a mesh-based MUS. The primary outcome was revision of the transvaginal mesh sling (including mesh removal/erosion/fistula, or urethrolysis). Two potential risk factors were analyzed: postoperative retention (within 30 days of procedure) and number of postoperative emergency room visits or hospital admissions for UTI symptoms. A total of 59,556 women had a MUS, of which 1598 (2.7%) required revision surgery. Of the 2025 women who presented to the emergency room or were admitted to hospital for postoperative retention, 212 (10.5%) required operative mesh revision. Of the 11,747 patients who had at least one postoperative UTI, 366 (3.1%) patients required operative mesh revision. In adjusted analysis, postoperative retention was significantly predictive of future reoperation (hazard ratio [HR] 3.46, 95% confidence interval [CI] 2.97-4.02), and this difference persisted when urethrolysis was excluded as a reason for sling revision (HR 3.08, 95% CI 2.62-3.63). Similarly, in adjusted analysis, each additional postoperative hospital visit for UTI symptoms increased the risk for surgical intervention for mesh complications (HR 1.74, 95% CI 1.61-1.87). Postoperative urinary retention and hospital presentation for UTI symptoms are associated with an increased risk of reoperation for MUS complications. These patients should be followed and investigated for mesh complications when appropriate. Copyright © 2016 Elsevier Inc. All rights reserved.

Toward An Unstructured Mesh Database

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Rezaei Mahdiraji, Alireza; Baumann, Peter Peter

2014-05-01

Unstructured meshes are used in several application domains such as earth sciences (e.g., seismology), medicine, oceanography, cli- mate modeling, GIS as approximate representations of physical objects. Meshes subdivide a domain into smaller geometric elements (called cells) which are glued together by incidence relationships. The subdivision of a domain allows computational manipulation of complicated physical structures. For instance, seismologists model earthquakes using elastic wave propagation solvers on hexahedral meshes. The hexahedral con- tains several hundred millions of grid points and millions of hexahedral cells. Each vertex node in the hexahedrals stores a multitude of data fields. To run simulation on such meshes, one needs to iterate over all the cells, iterate over incident cells to a given cell, retrieve coordinates of cells, assign data values to cells, etc. Although meshes are used in many application domains, to the best of our knowledge there is no database vendor that support unstructured mesh features. Currently, the main tool for querying and manipulating unstructured meshes are mesh libraries, e.g., CGAL and GRAL. Mesh li- braries are dedicated libraries which includes mesh algorithms and can be run on mesh representations. The libraries do not scale with dataset size, do not have declarative query language, and need deep C++ knowledge for query implementations. Furthermore, due to high coupling between the implementations and input file structure, the implementations are less reusable and costly to maintain. A dedicated mesh database offers the following advantages: 1) declarative querying, 2) ease of maintenance, 3) hiding mesh storage structure from applications, and 4) transparent query optimization. To design a mesh database, the first challenge is to define a suitable generic data model for unstructured meshes. We proposed ImG-Complexes data model as a generic topological mesh data model which extends incidence graph model to multi

Application of individually performed titanium mesh in infraorbital wall fracture reconstruction

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Kai-Jian Sun

2016-04-01

Full Text Available AIM:To discuss the application effect of individually performed titanium mesh in infraorbital wall fracture reconstruction. METHODS:Sixty-seven patients(67 eyesdiagnosed as infraorbital fracture from January 2011 to February 2014 were performed reconstruction with individually performed titanium mesh. The recovery of incision, visual acuity, eyeball mobility, diplopia and proptosis were monitored by post-operation follow-up which lasted for 1a. RESULTS:No infection, titanium mesh transposition, prolapse, deformities, exclusion or ectropion were occurred in the follow-up period. The eyeball embole was less than 2mm by bilateral proptosis contrast. The diplopia in 5 eyes were disappeared in 4 and approved in one. The eyeball descent in 2 cases was disappeared. The visual acuity was the same compared with pre-operation. The rate of disappeared diplopia at primary position was 93% and improved significantly in the other 3 patients. The rate of disappeared diplopia at peripheral visual field was 86% and improved significantly in the other 2 patients.CONCLUSION:The reconstruction effect of individually performed titanium mesh in infraorbital wall fracture was satisfied and safe.

Mesh optimization for microbial fuel cell cathodes constructed around stainless steel mesh current collectors

KAUST Repository

Zhang, Fang

2011-02-01

Mesh current collectors made of stainless steel (SS) can be integrated into microbial fuel cell (MFC) cathodes constructed of a reactive carbon black and Pt catalyst mixture and a poly(dimethylsiloxane) (PDMS) diffusion layer. It is shown here that the mesh properties of these cathodes can significantly affect performance. Cathodes made from the coarsest mesh (30-mesh) achieved the highest maximum power of 1616 ± 25 mW m-2 (normalized to cathode projected surface area; 47.1 ± 0.7 W m-3 based on liquid volume), while the finest mesh (120-mesh) had the lowest power density (599 ± 57 mW m-2). Electrochemical impedance spectroscopy showed that charge transfer and diffusion resistances decreased with increasing mesh opening size. In MFC tests, the cathode performance was primarily limited by reaction kinetics, and not mass transfer. Oxygen permeability increased with mesh opening size, accounting for the decreased diffusion resistance. At higher current densities, diffusion became a limiting factor, especially for fine mesh with low oxygen transfer coefficients. These results demonstrate the critical nature of the mesh size used for constructing MFC cathodes. © 2010 Elsevier B.V. All rights reserved.

Outcome of transvaginal mesh and tape removed for pain only.

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Hou, Jack C; Alhalabi, Feras; Lemack, Gary E; Zimmern, Philippe E

2014-09-01

Because there is reluctance to operate for pain, we evaluated midterm outcomes of vaginal mesh and synthetic suburethral tape removed for pain as the only indication. After receiving institutional review board approval we reviewed a prospective database of women without a neurogenic condition who underwent surgery for vaginal mesh or suburethral tape removal with a focus on pain as the single reason for removal and a minimum 6-month followup. The primary outcome was pain level assessed by a visual analog scale (range 0 to 10) at baseline and at each subsequent visit with the score at the last visit used for analysis. Parameters evaluated included demographics, mean time to presentation and type of mesh or tape inserted. From 2005 to 2013, 123 patients underwent surgical removal of mesh (69) and suburethral tape (54) with pain as the only indication. Mean followup was 35 months (range 6 to 59) in the tape group and 22 months (range 6 to 47) in the mesh group. The visual analog scale score decreased from a mean preoperative level of 7.9 to 0.9 postoperatively (p = 0.0014) in the mesh group and from 5.3 to 1.5 (p = 0.00074) in the tape group. Pain-free status, considered a score of 0, was achieved in 81% of tape and 67% of mesh cases, respectively. No statistically significant difference was found between the groups. When pain is the only indication for suburethral tape or vaginal mesh removal, a significant decrease in the pain score can be durably expected after removal in most patients at midterm followup. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Vaginal mucosal flap as a sling preservation for the treatment of vaginal exposure of mesh.

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Kim, Sea Young; Park, Jong Yeon; Kim, Han Kwon; Park, Chang Hoo; Kim, Sung Jin; Sung, Gi Teck; Park, Chang Myon

2010-06-01

Tension-free vaginal tape (TVT) procedures are used for the treatment of stress urinary incontinence in women. The procedures with synthetic materials can have a risk of vaginal erosion. We experienced transobturator suburethral sling (TOT) tape-induced vaginal erosion and report the efficacy of a vaginal mucosal covering technique. A total of 560 female patients diagnosed with stress urinary incontinence underwent TOT procedures at our hospital between January 2005 and August 2009. All patients succeeded in follow-ups, among which 8 patients (mean age: 50.5 years) presented with vaginal exposure of the mesh. A vaginal mucosal covering technique was performed under local anesthesia after administration of antibiotics and vaginal wound dressings for 3-4 days. Seven of the 8 patients complained of persistent vaginal discharge postoperatively. Two of the 8 patients complained of dyspareunia of their male partners. The one remaining patient was otherwise asymptomatic, but mesh erosion was discovered at the routine follow-up visit. Six of the 8 patients showed complete mucosal covering of the mesh after the operation (mean follow-up period: 16 moths). Vaginal mucosal erosion recurred in 2 patients, and the mesh was then partially removed. One patient had recurrent stress urinary incontinence. Vaginal mucosal covering as a sling preservation with continued patient continence may be a feasible and effective option for the treatment of vaginal exposure of mesh after TOT tape procedures.

In vitro extracellular matrix model to evaluate stroma cell response to transvaginal mesh.

Science.gov (United States)

Wu, Ming-Ping; Huang, Kuan-Hui; Long, Cheng-Yu; Yang, Chau-Chen; Tong, Yat-Ching

2014-04-01

The use of surgical mesh for female pelvic floor reconstruction has increased in recent years. However, there is paucity of information about the biological responses of host stroma cells to different meshes. This study was aimed to establish an in vitro experimental model to study the micro-environment of extracellular matrix (ECM) with embedded mesh and the stroma cell behaviors to different synthetic meshes. Matrigel multi-cellular co-culture system with embedded mesh was used to evaluate the interaction of stroma cells and synthetic mesh in a simulated ECM environment. Human umbilical vein endothelial cells (HUVEC) and NIH3T3 fibroblasts were inoculated in the system. The established multi-cellular Matrigel co-culture system was used to detect stroma cell recruitment and tube formation ability for different synthetic meshes. HUVEC and NIH3T3 cells were recruited into the mesh interstices and organized into tube-like structures in type I mesh material from Perigee, Marlex and Prolift 24 hr after cell inoculation. On the contrary, there was little recruitment of HUVEC and NIH3T3 cells into the type III mesh of intra-vaginal sling (IVS). The Matrigel multi-cellular co-culture system with embedded mesh offers a useful in vitro model to study the biological behaviors of stroma cells in response to different types of synthetic meshes. The system can help to select ideal mesh candidates before actual implantation into the human body. © 2013 Wiley Periodicals, Inc.

Surgical treatment of subcostal incisional hernia with polypropylene mesh - analysis of late results

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Marco Antonio de Oliveira Peres

Full Text Available OBJECTIVE: To evaluate the results of subcostal incisional hernia repair using polypropylene mesh, the technical aspects of musculo-aponeurotic reconstruction, routine fixation of supra-aponeurotic mesh and follow-up for five years.METHODS: We conducted a retrospective study that assessed 24 patients undergoing subcostal incisional hernia repair with use of polypropylene mesh; 15 patients (62.5% were female; ages ranged from 33 to 82, and 79.1% had comorbidities.RESULTS: Early complications: three cases (12.5% of wound infection, three cases (12.5% of seroma, one case (4.1% of hematoma; and one case (4.1% of wound dehiscence. Late complications occurred in one case (4.1% of hernia recurrence attributed to technical failure in the fixation of the mesh and in one case (4.1% of chronic pain. There were no cases of exposure or rejection of the mesh.CONCLUSION: The subcostal incisional hernia, though not very relevant, requires adequate surgical treatment. Its surgical correction involves rebuilding the muscle-aponeurotic defect, supra-aponeurotic fixation of polypropylene mesh, with less complexity and lower rates of complications and recurrences.

[Expandable metal mesh stents for treatment of tracheal stenoses and tracheomalacia].

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Müller, C; Dienemann, H; Hoffmann, H; Berger, H; Storck, M; Jolk, A; Schildberg, F W

1993-01-01

The treatment of tracheo-bronchial stenosis or tracheomalacia is mainly carried out by means of resection or tracheoplastic operative strategies. Since the introduction of metal-mesh stents, a definitive endoluminal therapy has to be considered under new aspects. Six patients with malignant stenosis or tracheomalacia due to compression were treated by implantation of Palmaz- or Wallstents. Immediately after the implantation, patients were relieved from dyspnoea, the forced inspiratory volume-1 (FIV1) was normalized. All implanted stents were well tolerated, even in the long-time follow-up (19 months). Bronchoscopic control showed overgrowth of the metal meshes by respiratory epithelium. The implantation of metal-mesh stents is an adequate alternative in the treatment of malignant stenosis and tracheomalacia.

Gear selectivity of large-mesh nets and drumlines used to catch ...

African Journals Online (AJOL)

Catches of sharks and bycatch in large-mesh nets and baited drumlines used by the Queensland Shark Control Program were examined to determine the efficacy of both gear types and assess fishing strategies that minimise their impacts. There were few significant differences in the size of both sharks and bycatch in the ...

Native-tissue repair of isolated primary rectocele compared with nonabsorbable mesh

DEFF Research Database (Denmark)

Madsen, Lene Duch; Nussler, Emil; Kesmodel, Ulrik Schioler

2017-01-01

and included 3988 women with a primary operation for rectocele between 2006 and 2014: 3908 women had native-tissue repair, 80 were operated with nonabsorbable mesh. No concurrent operations were performed. Pre- and perioperative data were collected from doctors and patients. Patient-reported outcomes were......INTRODUCTION: We evaluated patient-reported outcomes and complications after treatment of isolated primary rectocele in routine health-care settings using native-tissue repair or nonabsorbable mesh. METHODS: We used prospective data from the Swedish National Register for Gynaecological Surgery...

Split thickness skin graft meshing ratio indications and common practices.

Science.gov (United States)

Pripotnev, Stahs; Papp, Anthony

2017-12-01

Split thickness skin grafting is a commonly used technique in burn surgery for resurfacing wounds that are unlikely to heal without scarring. Meshing and expanding skin grafts allow for reconstruction of larger wounds with smaller donor sites. A retrospective chart review was performed of 210 patients with burns equal to or greater than 20% total body surface area admitted to Vancouver General Hospital between 1998 and 2014. Charts were reviewed to collect data on patient and burn demographics. A survey was sent to Canadian plastic surgeons registered with the CSPS to collect data on common practices in burn surgery nationwide. The patients that received 3:1 or higher meshed grafts were all flame burns, had a significantly higher average TBSA (51.89%±14.87 vs 29.13%±9.48, p=0.001), and a significantly higher full thickness burn TBSA (25.76%±21.97 vs 6.20%±9.04, p=0.001). We found no significant differences in gender, age, or burn location between the less than 2:1 and 3:1 or greater meshing ratio groups. The survey of plastic surgeons performing burn surgery in Canada revealed that 60% of responders had experience with skin grafts using meshing ratios of 3:1 or higher. Of these surgeons, 100% felt that burn size and 36% felt that burn location would influence their decision to use a 3:1 or higher meshing ratio. A larger burn size is the major influencing factor for the use of higher skin graft meshing ratios by Canadian burn surgeons. Furthermore, burn location determines the choice of donor and recipient sites in these cases. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Prevention of Incisional Hernias with Biological MeshA Systematic Review of the Literature

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FILIP ETIENNE MUYSOMS

2016-09-01

Full Text Available Background: Prophylactic mesh augmented reinforcement during closure of abdominal wall incisions has been proposed in patients with increased risk for development of incisional hernias (IH. As part of the BioMesh consensus project, a systematic literature review has been performed to detect those studies where MAR was performed with a non-permanent absorbable mesh (biological or biosynthetic. Methods: A computerized search was performed within 12 databases (Embase, Medline, Web-of-Science, Scopus, Cochrane, CINAHL, Pubmed publisher, Lilacs, Scielo, ScienceDirect, ProQuest, Google scholar with appropriate search terms. Qualitative evaluation was performed using the MINORS score for cohort studies and the Jadad score for RCTs. Results: For midline laparotomy incisions and stoma reversal wounds, 2 RCTs, 2 case control studies and 2 case series were identified. The studies were very heterogeneous in terms of mesh configuration (cross linked versus non cross linked, mesh position (intraperitoneal versus retromuscular versus onlay, surgical indication (gastric bypass versus aortic aneurysm, outcome results (effective versus non effective. After qualitative assessment we have to conclude that the level of evidence on the efficacy and safety of biological meshes for prevention of incisional hernias is very low. No comparative studies were found comparing biological mesh with synthetic non-absorbable meshes for the prevention of incisional hernias. Conclusion: There is no evidence supporting the use of non-permanent absorbable mesh (biological or biosynthetic for prevention of incisional hernias when closing a laparotomy in high-risk patients or in stoma reversal wounds. There is no evidence that a non-permanent absorbable mesh should be preferred to synthetic non-absorbable mesh both in clean or clean-contaminated surgery.

Transvaginal Excision of an Eroded Sacrocolpopexy Mesh by Using Single-Incision Laparoscopic Surgery Equipment.

Science.gov (United States)

Mohr, Stefan; Siegenthaler, Franziska; Imboden, Sara; Kuhn, Annette; Mueller, Michael D

To show a new technique of using single-incision laparoscopic surgery (SILS) equipment in vaginal surgery to create a "pneumovagina." Explanatory video demonstrating the technique and intraoperative findings. University hospital. The 68-year-old patient was referred with a vaginal mesh erosion that resulted in abscess formation at the vaginal apex. The patient was symptomatic with an increasingly foul-smelling vaginal discharge for about 1 year. She had a laparoscopic sacrocolpopexy in a remote hospital 22 months before the current operation and had a total abdominal hysterectomy 15 years ago. The, patient's history was uneventful without dyspareunia, incontinence or voiding difficulties, and she was otherwise content with the sacrocolpopexy result. The local institutional review board granted exemption for this publication. Frequently, pelvic organ prolapse can only be effectively treated if the surgical procedure comprises support of the central compartment. Laparoscopic sacrocolpopexy shows superior outcomes for this indication, with success rates of up to 96%. However, a rare side effect of laparoscopic sacrocolpopexy is mesh erosion, occurring in up to 2.4% [1]. These erosions are usually treated laparoscopically [2]. In this video we show an alternative route for excision of a symptomatic exposed mesh by using a transvaginal approach: The SILS trocar is used vaginally for abscess irrigation and mesh excision with minimally invasive instruments. For treatment of the abscess and removal of the exposed mesh, the SILS trocar was placed vaginally, and laparoscopic instruments were used. The abscess was incised, cleansed and irrigated, debrided, and the mesh excised. Because no mesh material was exposed after excision, the vagina was not closed to avoid creating a cavity with the risk of promoting reabscess formation, and secondary wound healing was anticipated. Laparoscopy was used to confirm that no intra-abdominal lesion coexisted or occurred. There were

Dynamic evaluation of pelvic floor reconstructive surgery using radiopaque meshes and three-dimensional helical CT

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Paulo Palma

2010-04-01

Full Text Available PURPOSE: This prospective study was performed to achieve visualization of the reestablishment of anatomy after reconstructive surgery in the different pelvic compartments with non-absorbable radiopaque meshes, providing valuable anatomic information for surgeons implanting meshes. MATERIALS AND METHODS: A total of 30 female patients with stress urinary incontinence (SUI, anterior and posterior vaginal wall prolapse, or both underwent surgical repair using radiopaque meshes after written informed consent. Patients with SUI underwent five different surgeries. Patients with anterior vaginal prolapse underwent a procedure using a combined pre-pubic and transobturator mesh, and those with posterior vaginal prolapse underwent posterior slingplasty. Three-dimensional reconstruction using helical CT was performed four weeks postoperatively. RESULTS: In all cases, the mesh was clearly visualized. Transobturator slings were shown at the midurethra, and the anchoring tails perforated the obturator foramen at the safety region. Mini-slings were in the proper place, and computed angiography revealed that the anchoring system was away from the obturator vessels. In patients undergoing procedure for anterior vaginal prolapse, both pre-pubic armpit and obturator slings were clearly seen and the mesh was in the proper position, supporting the bladder base and occluding the distal part of the urogenital hiatus. Transcoccygeal sacropexy revealed indirectly a well-supported "neo rectovaginal fascia" and the anchoring tails at the level of ischial spines. CONCLUSION: Three-dimensional helical tomography images of the female pelvis using radiopaque meshes have a potential role in improving our understanding of pelvic floor reconstructive surgeries. These radiopaque meshes might be the basis of a new investigative methodology.

OUR EXPERINCE WITH USE OF POSTERIOR MESH RECTOPEXY IN COMPLETE RECTAL PROLAPSE

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Sudhansu Sekhar Mohanty

2017-12-01

Full Text Available BACKGROUND Mesh rectopexy is one of the accepted treatment options for rectal prolapse. We used polypropylene posterior mesh rectopexy for prolapse rectum. The aim of the study was to see demographic, clinical and functional outcome of posterior mesh rectopexy in our setup. MATERIALS AND METHODS The case report of 33 patients under gone posterior abdominal mesh rectopexy in MKCG medical college and hospital from 1st July 2012 to 1st July 2017 were reviewed retrospectively and the patients were followed up in surgical OPD/telephonic questionnaire. All patients had undergone standard posterior abdominal mesh rectopexy without the division of lateral ligaments with utmost care for prevention of bleeding and nerve damage. RESULTS Out of 33 cases of abdominal rectopexy, 12 (36% were males and 21 (64% were females. 27 (82% were within 61-80 years of age group. The most common symptoms were mass per annum (100% followed by incontinence for liquid stool and flatus 24 (72%. There was no operative mortality. The average hospital stay 7.8 days (5-11 days. The constipation (p=0.019 and incontinence (p=0.0165 were better postoperatively. There was 1 (3% partial recurrence of rectal prolapse in 91-year-old lady in 2 years follow up. CONCLUSION The recurrence rate as well as clinical and functional outcome of open abdominal mesh rectopexy seems to be satisfactory, however, long-term effect has to be seen.

Adaptive radial basis function mesh deformation using data reduction

Science.gov (United States)

Gillebaart, T.; Blom, D. S.; van Zuijlen, A. H.; Bijl, H.

2016-09-01

Radial Basis Function (RBF) mesh deformation is one of the most robust mesh deformation methods available. Using the greedy (data reduction) method in combination with an explicit boundary correction, results in an efficient method as shown in literature. However, to ensure the method remains robust, two issues are addressed: 1) how to ensure that the set of control points remains an accurate representation of the geometry in time and 2) how to use/automate the explicit boundary correction, while ensuring a high mesh quality. In this paper, we propose an adaptive RBF mesh deformation method, which ensures the set of control points always represents the geometry/displacement up to a certain (user-specified) criteria, by keeping track of the boundary error throughout the simulation and re-selecting when needed. Opposed to the unit displacement and prescribed displacement selection methods, the adaptive method is more robust, user-independent and efficient, for the cases considered. Secondly, the analysis of a single high aspect ratio cell is used to formulate an equation for the correction radius needed, depending on the characteristics of the correction function used, maximum aspect ratio, minimum first cell height and boundary error. Based on the analysis two new radial basis correction functions are derived and proposed. This proposed automated procedure is verified while varying the correction function, Reynolds number (and thus first cell height and aspect ratio) and boundary error. Finally, the parallel efficiency is studied for the two adaptive methods, unit displacement and prescribed displacement for both the CPU as well as the memory formulation with a 2D oscillating and translating airfoil with oscillating flap, a 3D flexible locally deforming tube and deforming wind turbine blade. Generally, the memory formulation requires less work (due to the large amount of work required for evaluating RBF's), but the parallel efficiency reduces due to the limited

Preperitoneal Surgery Using a Self-Adhesive Mesh for Inguinal Hernia Repair

OpenAIRE

Mangram, Alicia; Oguntodu, Olakunle F.; Rodriguez, Francisco; Rassadi, Roozbeh; Haley, Michael; Shively, Cynthia J.; Dzandu, James K.

2014-01-01

Background and Objectives: Laparoscopic preperitoneal hernia repair with mesh has been reported to result in improved patient outcomes. However, there are few published data on the use of a totally extraperitoneal (TEP) approach. The purpose of this study was to present our experience and evaluate early outcomes of TEP inguinal hernia repair with self-adhesive mesh. Methods: This cohort study was a retrospective review of patients who underwent laparoscopic TEP inguinal hernial repair from Ap...

Laparoscopic appendicectomy for suspected mesh-induced appendicitis after laparoscopic transabdominal preperitoneal polypropylene mesh inguinal herniorraphy

Directory of Open Access Journals (Sweden)

Jennings Jason

2010-01-01

Full Text Available Laparoscopic inguinal herniorraphy via a transabdominal preperitoneal (TAPP approach using Polypropylene Mesh (Mesh and staples is an accepted technique. Mesh induces a localised inflammatory response that may extend to, and involve, adjacent abdominal and pelvic viscera such as the appendix. We present an interesting case of suspected Mesh-induced appendicitis treated successfully with laparoscopic appendicectomy, without Mesh removal, in an elderly gentleman who presented with symptoms and signs of acute appendicitis 18 months after laparoscopic inguinal hernia repair. Possible mechanisms for Mesh-induced appendicitis are briefly discussed.

The Disability Impact and Associated Cost per Disability in Women Who Underwent Surgical Revision of Transvaginal Mesh Kits for Prolapse Repair.

Science.gov (United States)

Javadian, Pouya; Shobeiri, S Abbas

2017-09-13

The aim of this study was to investigate disability impact in patients and cost to the families of patients who have had complications of transvaginal prolapse mesh kits and underwent surgical revision. Patients who developed complications of transvaginal mesh kits for prolapse and who had undergone vaginal prolapse mesh surgical revision/removal in 2009 to 2014 at a single institution were identified by Current Procedural Terminology codes. The group was invited to complete a phone survey pertaining to the initial vaginal mesh used for prolapse surgery utilizing Sheehan Disability Scale (scale 0-10) and Years of life Lived with Disability (YLDs) questionnaires. The data collected were used to estimate the disability and cost analysis. We used our data to estimate the economic and quality-of-life impact of vaginal mesh complications on patients in the United States RESULTS: Sixty-two patients (62/198 [31.2%]) were consented to participate and completed the questionnaires by phone. Extremely disabled patients were 18 (29%) of 62 of whole cases, and 5 (8%) of 62 reported that they had no disability after vaginal mesh surgery. The median for overall disability score after vaginal mesh procedure was 8 (which reflects marked disability on a scale of 0-10). The majority of patients missed a median of 12 months of their school or work because of their mesh complications. Thirty-seven (59.6%) of 62 did not improve after mesh removal. Twenty-one (33.9%) of 62 stated that their family income dropped because of productivity loss related to mesh complications. The mean time between vaginal mesh surgery and mesh removal procedure was 4.7 years. Sheehan Disability Scale scores are significantly correlated with YLDs outcomes. Patients' overall disability score showed a significant correlation with YLDs scores (P mesh for prolapse reduction complications had a sustained disability impact that continued despite mesh removal. Likewise, the complications were associated with

A prospective randomised trial comparing mesh types and fixation in totally extraperitoneal inguinal hernia repairs.

Science.gov (United States)

Cristaudo, Adam; Nayak, Arun; Martin, Sarah; Adib, Reza; Martin, Ian

2015-05-01

The totally extraperitoneal (TEP) approach for surgical repair of inguinal hernias has emerged as a popular technique. We conducted a prospective randomised trial to compare patient comfort scores using different mesh types and fixation using this technique. Over a 14 month period, 146 patients underwent 232 TEP inguinal hernia repairs. We compared the comfort scores of patients who underwent these procedures using different types of mesh and fixation. A non-absorbable 15 × 10 cm anatomical mesh fixed with absorbable tacks (Control group) was compared with either a non-absorbable 15 × 10 cm folding slit mesh with absorbable tacks (Group 2), a partially-absorbable 15 × 10 cm mesh with absorbable tacks (Group 3) or a non-absorbable 15 × 10 cm anatomical mesh fixed with 2 ml fibrin sealant (Group 4). Outcomes were compared at 1, 2, 4 and 12 weeks using the Carolina Comfort Scale (CCS) scores. At 1, 2, 4 and 12 weeks, the median global CCS scores were low for all treatment groups. Statistically significant differences were seen only for median CCS scores and subscores with the use of partially-absorbable mesh with absorbable tacks (Group 3) at weeks 2 and 4. However, these were no longer significant at week 12. In this study, the TEP inguinal hernia repair with minimal fixation results in low CCS scores. There were no statistical differences in CCS scores when comparing types of mesh, configuration of the mesh or fixation methods. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

The IUGA/ICS classification of synthetic mesh complications in female pelvic floor reconstructive surgery: a multicenter study.

Science.gov (United States)

Miklos, John R; Chinthakanan, Orawee; Moore, Robert D; Mitchell, Gretchen K; Favors, Sheena; Karp, Deborah R; Northington, Gina M; Nogueiras, Gladys M; Davila, G Willy

2016-06-01

The objective was to report patterns of sling and transvaginal mesh-related complications using the IUGA/ICS classification of prosthesis-related complications. This was a retrospective chart review of all patients who underwent surgical removal of sling, transvaginal mesh, and sacrocolpopexy for mesh-related complications from 2011 to 2013 at three tertiary referral centers. The International Urogynecological Association (IUGA)/International Continence Society (ICS) classification system was utilized. We identified 445 patients with mesh complications, 506 pieces of synthetic mesh were removed, and 587 prostheses-related complications were classified. 3.7 % of patients had viscus organ penetration or vaginal exposure as their presenting chief complaint and 59.7 % were classified as not having any vaginal epithelial separation or category 1. The most common category was spontaneous pain (1Be: 32.5 %) followed by dyspareunia (1Bc: 14.7 %). The sling group was 20 % more likely to have pain compared with the pelvic organ prolapse (POP) mesh group (OR 1.2, 95 % CI 0.8-1.6). The most commonly affected site (S2) was away from the suture line (49 %). Compared with the sling group, the POP group had a higher rate of mesh exposure, which mostly occurred at the suture line area. The majority of patients presented with mesh-related complications more than 1 year post-insertion (T4; average 3.68 ± 2.47 years). Surgeons should be aware that patients with vaginal mesh complications routinely exhibit complications more than 1 year after the implantation with pain as the most common presenting symptom.

Analysis of Surgical Outcomes and Determinants of Litigation Among Women With Transvaginal Mesh Complications.

Science.gov (United States)

Zoorob, Dani; Karram, Mickey; Stecher, Anna; Maxwell, Rose; Whiteside, James

To identify litigation predictors among women with complications of transvaginal mesh. Chart review and patient survey were conducted among women who had undergone a complication-related explant of a transvaginal prolapse or incontinence sling mesh. Trained study personnel administered a 57-question survey addressing subjective complaints related to bowel, bladder, sexual dysfunction, and development of pain or recurrent prolapse. These data were analyzed with respect to the subject's reported pursuit of litigation related to the mesh complication. Categorical and continuous variables were analyzed using the χ test and the t test as indicated. Ninety-five (68%) of 139 women completed the surveys with 60% of the patients pursuing litigation at the time of the survey. Individual risk factors for pursuing litigation included development of vaginal pain after mesh placement (P = 0.01); dyspareunia after mesh placement (P = 0.01); persistence of dyspareunia, suprapubic pain, and groin pain after mesh excision (P = 0.04, P = 0.02, and P = 0.001, respectively); unsuccessful attempts at conservative management of pelvic pain using pelvic floor rehabilitation (P = 0.002). There is an association between a higher likelihood of pursuing litigation and new-onset or persistent pain symptoms attributable to transvaginal mesh.

Practical implementation of tetrahedral mesh reconstruction in emission tomography

Science.gov (United States)

Boutchko, R.; Sitek, A.; Gullberg, G. T.

2013-05-01

This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio

Practical implementation of tetrahedral mesh reconstruction in emission tomography

International Nuclear Information System (INIS)

Boutchko, R; Gullberg, G T; Sitek, A

2013-01-01

This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio

Polypropylene mesh as an alternative option for uterine preservation in pelvic reconstruction in patients with uterine prolapse.

Science.gov (United States)

Huang, Kuan-Hui; Chuang, Fei-Chi; Fu, Hung-Chun; Kung, Fu-Tsai

2012-01-01

  The aim of this study was to evaluate the efficacy and safety of polypropylene mesh for uterine preservation during pelvic reconstruction in patients with severe uterine prolapse. The study included 67 women with severe uterine prolapse (pelvic organ prolapse quantification stage III/IV) who received transvaginal mesh reconstruction with uterine preservation. Surgery combined with a transobturator membrane sling procedure (tension-free vaginal tape-transobturator route) was performed in 54 patients. Among them, 18 had urodynamic stress incontinence, 30 had occult stress urinary incontinence, and six had mixed urinary incontinence. Objective assessments were carried out with the pelvic organ prolapse quantification staging system, urodynamic examination, and 1-h pad test. Evaluation of urinary and prolapse symptoms comprised the subjective assessment. The mean follow-up interval was 19.6 months (12-40 months). The objective cure rate for the treatment of uterine prolapse was 89.5%, and the objective cure rate for the treatment of urinary incontinence was more than 90%. Uterine preservation in pelvic reconstruction is technically feasible and the subjective and objective assessments imply that uterine preservation in pelvic reconstruction is an alternative option for indicated patients. © 2011 The Authors. Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology.

Use of biologic mesh at ostomy takedown to prevent incisional hernia: A case series

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Sepehr Lalezari

Full Text Available Introduction: Incisional hernias are a relatively common occurrence after ostomy takedown with a incidence of 30–35%. The use of biologic mesh offers a means to bolster the stoma incision site with a lower risk of infection than synthetic mesh. Methods: This study represents a retrospective chart review of six patients who underwent stoma takedown and had biologic mesh placed in the retrorectus position during repair from March 2015 until March 2016. Results: There has been a zero-rate of hernia occurrence for the six patients who underwent stoma takedown. No incisional hernias were noted on physical exam with follow up ranging from 11 to 25 months. Conclusion: We conclude that placement of biologic mesh is a safe and effective way of preventing incisional hernias at stoma sites. Keywords: Biologic mesh, Ostomy takedown, Stoma reversal, Incisional hernia, Parastomal hernia, Hernia prophylaxis

Indications and Complications Associated with the Removal of 506 Pieces of Vaginal Mesh Used in Pelvic Floor Reconstruction: A Multicenter Study.

Science.gov (United States)

Miklos, John R; Chinthakanan, Orawee; Moore, Robert D; Karp, Deborah R; Nogueiras, Gladys M; Davila, G Willy

2016-10-26

Synthetic mesh utilized to treat stress urinary incontinence (SUI) and pelvic organ prolapse (POP) can often result in postoperative complications. The objectives of this study were to determine: 1) the most common indications for mesh removal; 2) the incidences of the removal of specific mesh procedures (such as suburethral sling [SUS], transvaginal mesh [TVM], or sacrocolpopexy); and 3) the idences and types of surgical complications associated with mesh removal. This was a retrospective study. Design Classification: Canadian Task Force II-3. Three tertiary referral centers in the United States. We examined data from all patients at the three centers who underwent surgical removal of synthetic materials from previous SUS, TVM, and sacrocolpopexy procedures for mesh-related complications from 2011 to 2013. Patients underwent vaginal, intra-abdominal, and inguinal mesh revisions by cutting, partial removal, or total removal of the mesh for mesh-related complications. Overall, 445 patients with complications underwent mesh removal laparoscopically, via groin dissection and/or transvaginally. There were a total of 506 mesh products removed. Of these, 56.5% were slings and 43.5% were for pelvic organ prolapse (POP). Synthetic mesh removed from patients included: transvaginal mesh (TVM) anterior for anterior vaginal prolapse, TVM posterior for posterior vaginal prolapse, sacrocolpopexy mesh, and suburethral slings (SUS) for stress urinary incontinence. Synthetic SUS removed included: retropubic (RPS), transobturator (TOT), and single-incision slings (SIS). TOT was the most common type of sling removed. Patients with a sling who only complained of vaginal pain with or without intercourse underwent a vaginal approach for surgical revision/removal of the sling (86.6%). Patients with an RPS with lower abdominal/suprapubic pain and vaginal pain underwent a vaginal and laparoscopic approach for sling removal (18.4%). Patients with a TOT sling who complained of vaginal and

Surface meshing with curvature convergence

KAUST Repository

Li, Huibin; Zeng, Wei; Morvan, Jean-Marie; Chen, Liming; Gu, Xianfengdavid

2014-01-01

Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

Surface meshing with curvature convergence

KAUST Repository

Li, Huibin

2014-06-01

Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

The Importance of Registries in the Postmarketing Surveillance of Surgical Meshes.

Science.gov (United States)

Köckerling, Ferdinand; Simon, Thomas; Hukauf, Martin; Hellinger, Achim; Fortelny, Rene; Reinpold, Wolfgang; Bittner, Reinhard

2017-06-07

To assess the role of registries in the postmarketing surveillance of surgical meshes. To date, surgical meshes are classified as group II medical devices. Class II devices do not require premarket clearance by clinical studies. Ethicon initiated a voluntary market withdrawal of Physiomesh for laparoscopic use after an analysis of unpublished data from the 2 large independent hernia registries-Herniamed German Registry and Danish Hernia Database. This paper now presents the relevant data from the Herniamed Registry. The present analysis compares the prospective perioperative and 1-year follow-up data collected for all patients with incisional hernia who had undergone elective laparoscopic intraperitoneal onlay mesh repair either with Physiomesh (n = 1380) or with other meshes recommended in the guidelines (n = 3834). Patients with Physiomesh repair had a markedly higher recurrence rate compared with the other recommended meshes (12.0% vs 5.0%; P manufacturing company must be taken into account.This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0.

Do patients prefer mesh or anterior colporrhaphy for primary correction of anterior vaginal wall prolapse: a labelled discrete choice experiment

NARCIS (Netherlands)

Notten, K. J. B.; Essers, B. A.; Weemhoff, M.; Rutten, A. G. H.; Donners, J. J. A. E.; van Gestel, I.; Kruitwagen, R. F. M. P.; Roovers, J. P. W. R.; Dirksen, C. D.

2015-01-01

We investigated patients' preferences for anterior colporrhaphy or mesh surgery as surgical correction of anterior vaginal wall prolapse. Labelled discrete choice experiment. Three Dutch teaching hospitals. Women with anterior vaginal wall prolapse Pelvic Organ Prolapse Quantification stage 2 or

Work in progress: a channel selection algorithm for a TVWS mesh network

CSIR Research Space (South Africa)

Zlobinsky, Natasha

2016-09-01

Full Text Available and routing for throughput optimization in multi-radio wireless mesh networks,” Proc. 11th Annu. Int. Conf. Mob. Comput. Netw. - MobiCom ’05, p. 58, 2005. [4] M. R. Rai, S. Vahid, and K. Moessner, “SINR based Topology Control for Multihop Wireless Networks...

Anterior lumbar fusion with titanium threaded and mesh interbody cages.

Science.gov (United States)

Rauzzino, M J; Shaffrey, C I; Nockels, R P; Wiggins, G C; Rock, J; Wagner, J

1999-12-15

metastatic breast cancer who had undergone an L-3 corpectomy with placement of a mesh cage. Although her back pain was immediately resolved, she died of systemic disease 3 months after surgery and before fusion could occur. Complications related to the anterior approach included two vascular injuries (two left common iliac vein lacerations); one injury to the sympathetic plexus; one case of superficial phlebitis; two cases of prolonged ileus (greater than 48 hours postoperatively); one anterior femoral cutaneous nerve palsy; and one superficial wound infection. No deaths were directly related to the surgical procedure. There were no cases of dural laceration and no nerve root injury. There were no cases of deep venous thrombosis, pulmonary embolus, retrograde ejaculation, abdominal hernia, bowel or ureteral injury, or deep wound infection. Fusion-related complications included an iliac crest hematoma and prolonged donor-site pain in one patient. There were no complications related to placement or migration of the cages, but there was one case of screw fracture of the Kaneda device that did not require revision. The authors conclude that anterior lumbar fusion performed using titanium interbody or mesh cages, packed with autologous bone, is an effective, safe method to achieve fusion in a wide variety of pathological conditions of the thoracolumbar spine. The fusion rate of 96% compares favorably with results reported in the literature. The complication rate mirrors the low morbidity rate associated with the anterior approach. A detailed study of clinical outcomes is in progress. Patient selection and strategies for avoiding complication are discussed.

Necrotising fasciitis after hysterectomy and concomitant transvaginal mesh repair in a patient with pelvic organ prolapse.

Science.gov (United States)

Pushkar, Dmitry Y; Vasilchenko, Mikhail I; Kasyan, George R

2013-10-01

Necrotising fasciitis is a severe form of soft tissue infection. Herein, we present an unreported complication of the transvaginal repair of a pelvic organ prolapse (POP) with trocar-guided polypropylene mesh and a concomitant hysterectomy. A 61-year-old Caucasian female who had been using an intrauterine device (IUD) for 30 years presented with a stage 3 pelvic organ prolapse. A genital ultrasound examination confirmed the presence of an IUD, but found no endometrial abnormalities. The surgical management was limited to a transvaginal hysterectomy and simultaneous anterior vaginal wall repair augmented with trocar-guided mesh. A morphological examination of the removed uterus confirmed the presence of the intrauterine device and additionally found endometrial cancer (T1N0M0), which was not revealed during the preoperative ultrasound. Within 6 days of the surgery, she developed anaerobic bilateral necrotising fasciitis on both thighs. Non-clostridial streptococci were identified in the wound. After 18 days of intensive care, the patient died of fatal coagulopathy.

Voltammetry at micro-mesh electrodes

Directory of Open Access Journals (Sweden)

Wadhawan Jay D.

2003-01-01

Full Text Available The voltammetry at three micro-mesh electrodes is explored. It is found that at sufficiently short experimental durations, the micro-mesh working electrode first behaves as an ensemble of microband electrodes, then follows the behaviour anticipated for an array of diffusion-independent micro-ring electrodes of the same perimeter as individual grid-squares within the mesh. During prolonged electrolysis, the micro-mesh electrode follows that behaviour anticipated theoretically for a cubically-packed partially-blocked electrode. Application of the micro-mesh electrode for the electrochemical determination of carbon dioxide in DMSO electrolyte solutions is further illustrated.

[Current state of transvaginal meshes by resolution of pelvic organ prolapse].

Science.gov (United States)

Jírová, J; Pán, M

Treatment of pelvic organs prolapse with transvaginal mesh kits represents nowadays a widespread surgical method, which partially replaced classic operations due to high success rate and low count of recurrences. Just like any other surgical method, the placement of transvaginal mesh is linked with occurrence of complications. In this article we attempt to review the more and less known facts about trans-vaginal meshes, their efficacy, count of recurrence and the spectrum of complications and we try to compare this technique with traditional surgical methods used to treat pelvic organs prolapse (without graft materials). Review. Department of Obstetrics and Gynecology, Regional hospital Mladá Boleslav a.s., Mladá Boleslav. Overview of the results of recent studies published in the Czech and English language in recent years. Pelvic organ prolapse repair with vaginal mesh has generally lower count of relapse especially in patients with wide genital hiatal area and with major levator ani avulsion. The spectrum of complications differs from classical techniques because of the presence of synthetic nonabsorbable material. Some of the specific complications we did not encounter during classical operations include vaginal mesh erosion, infection of mesh associated with chronic pelvic pain, dyspareunia, protrusion of the mesh into the closest organs or the rejection and progressive extrusion of the mesh. Primary enthusiasm has now been replaced with worries of major complications. Future tasks should therefore be aimed at minimizing the rate of complications associated with transvaginal meshes. Except using well-known and safe materials and providing specialized training of physicians for each mesh implantation technique, other precautions outlined in this article should help, such as a closer specification of indication for the application of transvaginal mesh.

Streaming simplification of tetrahedral meshes.

Science.gov (United States)

Vo, Huy T; Callahan, Steven P; Lindstrom, Peter; Pascucci, Valerio; Silva, Cláudio T

2007-01-01

Unstructured tetrahedral meshes are commonly used in scientific computing to represent scalar, vector, and tensor fields in three dimensions. Visualization of these meshes can be difficult to perform interactively due to their size and complexity. By reducing the size of the data, we can accomplish real-time visualization necessary for scientific analysis. We propose a two-step approach for streaming simplification of large tetrahedral meshes. Our algorithm arranges the data on disk in a streaming, I/O-efficient format that allows coherent access to the tetrahedral cells. A quadric-based simplification is sequentially performed on small portions of the mesh in-core. Our output is a coherent streaming mesh which facilitates future processing. Our technique is fast, produces high quality approximations, and operates out-of-core to process meshes too large for main memory.

Complications of Transvaginal Mesh for Pelvic Organ Prolapse and Stress Urinary Incontinence: Tips for Prevention, Recognition, and Management.

Science.gov (United States)

MacDonald, Susan; Terlecki, Ryan; Costantini, Elisabetta; Badlani, Gopal

2016-08-01

Mesh-related complications following transvaginal management of pelvic organ prolapse (POP) and/or stress urinary incontinence (SUI) have received significant attention in the last decade. We sought to identify patient, product, and technical factors associated with an increased risk of complications after mesh-based transvaginal repair of anterior POP and SUI. In this review we clarify the different pattern of complications after POP and SUI repairs. Our aim is to provide a practical evidence-based guide for physicians to prevent and, if necessary, manage product-associated complications in a stepwise manner. We conducted a comprehensive PubMed search of all English-language articles published from 2010 to June 2016, using these search terms: mesh, pelvic organ prolapse, and stress urinary incontinence. Expert opinion is also provided. Mesh-related complications are much lower after repair of SUI compared with POP, despite its more frequent use. Vaginal exposure is the most common mesh-specific complication. Patients may present with vaginal discharge, dyspareunia, pain, recurrent urinary tract infection, and/or hematuria. Conversely, patients may be asymptomatic. Small asymptomatic mesh exposures (mesh encountered within the urinary tract must be fully excised. Following excision, pain may persist in up to 50% of patients. Vaginal extrusion, persistent pain, and urethral and/or bladder erosion are the three most common product-specific complications following mesh-based repair for SUI or POP. Conservative therapies may be attempted, but most patients ultimately require partial or complete mesh excision. We reviewed the recent literature on mesh-related complications after repair of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Vaginal exposure, persistent pain, and erosion into the urinary tract are the most common. These often require surgical management, best suited to a urologist with training and experience in this area. Evidence supports

Outcomes of trocar-guided Gynemesh PS™ versus single-incision trocarless Polyform™ transvaginal mesh procedures.

Science.gov (United States)

Larouche, Maryse; Merovitz, Lisa; Correa, José A; Walter, Jens-Erik

2015-01-01

The aim of the study was to compare rates of success, mesh exposure, and surgical re-intervention after trocar-guided Gynemesh PS™ and trocarless Polyform™ transvaginal mesh procedures. We conducted a retrospective cohort study of all transvaginal mesh procedures performed at our centers between January 2008 and May 2012. Multiple logistic regression models were used to explore the binary outcomes of objective and subjective success rates, as well as mesh exposure and re-intervention rates, between the two procedures after adjustment for patient's age, parity, body mass index, smoking status, previous hysterectomy, previous prolapse surgery, and follow-up time. We included 103 transvaginal mesh procedures (47 trocar-guided Gynemesh PS™ and 56 trocarless Polyform™). In both groups, Pelvic Organ Prolapse Quantification (POP-Q) scores were significantly improved after the procedure. Median follow-up was 340 days and interquartile range (IQR) 152-644. Objective success rates were 55.3 % (26/47) in the trocar group and 60.7 % (34/56) in the trocarless group (p = 0.9), whereas subjective success was 83.0 % (39/47) and 94.6 % (53/56), respectively (p = 0.1). The adjusted odds of developing mesh exposure were significantly less after trocarless transvaginal mesh procedures compared to trocar-guided ones [odds ratio (OR) 0.16, 95 % confidence interval (CI) 0.03-0.97]. Surgical re-interventions, aimed mostly at treating recurrent prolapse, mesh exposure, and latent stress urinary incontinence, were also significantly less frequent after trocarless procedures [5 patients (8.9 %) requiring re-intervention versus 15 (31.9 %), respectively, adjusted OR 0.15, 95 % CI 0.04-0.60]. Trocar-guided Gynemesh PS™ and trocarless Polyform™ transvaginal mesh systems result in similar objective and subjective success rates. The newer Polyform™ mesh results in significantly fewer mesh exposures and surgical re-interventions.

Efficacy of Prophylactic Mesh in End-Colostomy Construction: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Science.gov (United States)

Wang, Shuanhu; Wang, Wenbin; Zhu, Bing; Song, Guolei; Jiang, Congqiao

2016-10-01

Parastomal hernia is a very common complication after colostomy, especially end-colostomy. It is unclear whether prophylactic placement of mesh at the time of stoma formation could prevent parastomal hernia formation after surgery for rectal cancer. A systematic review and meta-analysis were conducted to evaluate the efficacy of prophylactic mesh in end-colostomy construction. PubMed, Embase, and the Cochrane Library were searched, covering records entered from their inception to September 2015. Randomized controlled trials (RCTs) comparing stoma with mesh to stoma without mesh after surgery for rectal cancer were included. The primary outcome was the incidence of parastomal hernia. Pooled risk ratios (RR) with 95 % confidence intervals (CI) were obtained using random effects models. Six RCTs containing 309 patients were included. Parastomal hernia occurred in 24.4 % (38 of 156) of patients with mesh and 50.3 % (77 of 153) of patients without mesh. Meta-analysis showed a lower incidence of parastomal hernia (RR, 0.42; 95 % CI 0.22-0.82) and reoperation related to parastomal hernia (RR, 0.23; 95 % CI 0.06-0.89) in patients with mesh. Stoma-related morbidity was similar between mesh group and non-mesh group (RR, 0.65; 95 % CI 0.33-1.30). Prophylactic placement of a mesh at the time of a stoma formation seems to be associated with a significant reduction in the incidence of parastomal hernia and reoperation related to parastomal hernia after surgery for rectal cancer, but not the rate of stoma-related morbidity. However, the results should be interpreted with caution because of the heterogeneity among the studies.

MeshVoro: A Three-Dimensional Voronoi Mesh Building Tool for the TOUGH Family of Codes

Energy Technology Data Exchange (ETDEWEB)

Freeman, C. M.; Boyle, K. L.; Reagan, M.; Johnson, J.; Rycroft, C.; Moridis, G. J.

2013-09-30

Few tools exist for creating and visualizing complex three-dimensional simulation meshes, and these have limitations that restrict their application to particular geometries and circumstances. Mesh generation needs to trend toward ever more general applications. To that end, we have developed MeshVoro, a tool that is based on the Voro (Rycroft 2009) library and is capable of generating complex threedimensional Voronoi tessellation-based (unstructured) meshes for the solution of problems of flow and transport in subsurface geologic media that are addressed by the TOUGH (Pruess et al. 1999) family of codes. MeshVoro, which includes built-in data visualization routines, is a particularly useful tool because it extends the applicability of the TOUGH family of codes by enabling the scientifically robust and relatively easy discretization of systems with challenging 3D geometries. We describe several applications of MeshVoro. We illustrate the ability of the tool to straightforwardly transform a complex geological grid into a simulation mesh that conforms to the specifications of the TOUGH family of codes. We demonstrate how MeshVoro can describe complex system geometries with a relatively small number of grid blocks, and we construct meshes for geometries that would have been practically intractable with a standard Cartesian grid approach. We also discuss the limitations and appropriate applications of this new technology.

Self-adhesive mesh for Lichtenstein inguinal hernia repair. Experience of a single center.

Science.gov (United States)

Tarchi, P; Cosola, D; Germani, P; Troian, M; De Manzini, N

2014-06-01

Lichtenstein tension-free mesh repair is the most frequently performed procedure for inguinal hernioplasty. In the past surgery aimed to control recurrences. Nowadays it is important to avoid postoperative chronic pain and thus several studies have examined the potential role of meshes in causing postoperative pain. The purpose of this study was to retrospectively assess the early and long-term results after Lichtenstein tension-free repair using a self-adhesive mesh (Parietex ProgripTM - Covidien, Germany) in a single center. The study enrolled 211 patients, 199 males (94.3%) and 12 females (5.7%), mean age 62 years (28-90 years), between January 2008 and December 2011. Of these, 206 had primary inguinal hernias while 5 were recurrences following previous tension repair. Ten different general surgeons, including residents, performed Lichtenstein hernia repair using a 12 x 8-cm Parietex ProgripTM mesh. In 88.1% of patients no additional fixation was used, while in 11.9% a single 2-0 polypropylene stitch was placed on the pubic bone. A 1-10 visual analog scale (VAS) was used to assess postoperative pain, evaluating it at 1 week, 1 month and 12, 24 and 36 months. Local paresthesia was assessed at same intervals. Any pain sensation lasting longer than 3 months postoperatively, or requiring injection of analgesics was defined as chronic pain. Mean operating time was 64.1 minutes (SD ± 21.14). There were no intraoperative complications. Early postoperative complications included hematoma-seroma (5.7% cases), superficial wound infection (1%), urinary retention (0.5%), and scrotal swelling (1%). The main follow-up period was 3 years, although patients operated between 2009 and 2011 underwent a shorter follow-up. At one-year follow-up, 17 patients reported groin discomfort, but did not require analgesics. Three patients reported moderate pain, requiring occasional use of oral analgesics, and 2 of these described a discontinuous pain mainly during movement. One patient

Fibrin sealant for mesh fixation in laparoscopic groin hernia repair does not increase long-term recurrence

DEFF Research Database (Denmark)

Fenger, Andreas Qwist; Helvind, Neel Maria; Pommergaard, Hans-Christian

2016-01-01

BACKGROUND: Methods of groin hernia repair include laparoscopic techniques using tissue-penetrating mesh fixation or non-penetrating fixation. Concerns regarding hernia repair include postoperative chronic pain, sexual dysfunction, and recurrence. Earlier estimations of recurrence rates have......) laparoscopic groin hernia repair using either fibrin sealant or tacks for mesh fixation. METHODS: This study used data from the Danish Hernia Database to create the following cohort: All patients operated laparoscopically for primary groin hernia with a TAPP procedure using fibrin sealant for mesh fixation...... difference in long-term reoperation rates and clinical recurrences in patients undergoing TAPP repair with meshes fixated with fibrin sealant compared with tacks....

Improving the selectivity of beam trawls in The Netherlands: the effect of large mesh top panels on the catch rates of sole, plaice, cod and whiting

NARCIS (Netherlands)

Marlen, van B.

2003-01-01

This paper presents the results of experiments aimed to improve the selectivity of beam trawls in the North Sea for roundfish whilst minimizing losses on target flatfish. Large-meshed top panels were designed for the tickler chain type of beam trawls used in this fishery. The design process involved

Mesh optimization for microbial fuel cell cathodes constructed around stainless steel mesh current collectors

KAUST Repository

Zhang, Fang; Merrill, Matthew D.; Tokash, Justin C.; Saito, Tomonori; Cheng, Shaoan; Hickner, Michael A.; Logan, Bruce E.

2011-01-01

that the mesh properties of these cathodes can significantly affect performance. Cathodes made from the coarsest mesh (30-mesh) achieved the highest maximum power of 1616 ± 25 mW m-2 (normalized to cathode projected surface area; 47.1 ± 0.7 W m-3 based on liquid

SUPERIMPOSED MESH PLOTTING IN MCNP

Energy Technology Data Exchange (ETDEWEB)

J. HENDRICKS

2001-02-01

The capability to plot superimposed meshes has been added to MCNP{trademark}. MCNP4C featured a superimposed mesh weight window generator which enabled users to set up geometries without having to subdivide geometric cells for variance reduction. The variance reduction was performed with weight windows on a rectangular or cylindrical mesh superimposed over the physical geometry. Experience with the new capability was favorable but also indicated that a number of enhancements would be very beneficial, particularly a means of visualizing the mesh and its values. The mathematics for plotting the mesh and its values is described here along with a description of other upgrades.

Mesh Nanoelectronics: Seamless Integration of Electronics with Tissues.

Science.gov (United States)

Dai, Xiaochuan; Hong, Guosong; Gao, Teng; Lieber, Charles M

2018-02-20

nanoelectronics into rodent brains. First, we describe the design of ultraflexible mesh nanoelectronics with size features and mechanical properties similar to brain tissue and a novel syringe-injection methodology that allows the mesh nanoelectronics to be precisely delivered to targeted brain regions in a minimally invasive manner. Next, we discuss time-dependent histology studies showing seamless and stable integration of mesh nanoelectronics within brain tissue on at least one year scales without evidence of chronic immune response or glial scarring characteristic of conventional implants. Third, armed with facile input/output interfaces, we describe multiplexed single-unit recordings that demonstrate stable tracking of the same individual neurons and local neural circuits for at least 8 months, long-term monitoring and stimulation of the same groups of neurons, and following changes in individual neuron activity during brain aging. Moving forward, we foresee substantial opportunities for (1) continued development of mesh nanoelectronics through, for example, broadening nanodevice signal detection modalities and taking advantage of tissue-like properties for selective cell targeting and (2) exploiting the unique capabilities of mesh nanoelectronics for tackling critical scientific and medical challenges such as understanding and potentially ameliorating cell and circuit level changes associated with natural and pathological aging, as well as using mesh nanoelectronics as active tissue scaffolds for regenerative medicine and as neuroprosthetics for monitoring and treating neurological diseases.

Cache-Oblivious Mesh Layouts

International Nuclear Information System (INIS)

Yoon, S; Lindstrom, P; Pascucci, V; Manocha, D

2005-01-01

We present a novel method for computing cache-oblivious layouts of large meshes that improve the performance of interactive visualization and geometric processing algorithms. Given that the mesh is accessed in a reasonably coherent manner, we assume no particular data access patterns or cache parameters of the memory hierarchy involved in the computation. Furthermore, our formulation extends directly to computing layouts of multi-resolution and bounding volume hierarchies of large meshes. We develop a simple and practical cache-oblivious metric for estimating cache misses. Computing a coherent mesh layout is reduced to a combinatorial optimization problem. We designed and implemented an out-of-core multilevel minimization algorithm and tested its performance on unstructured meshes composed of tens to hundreds of millions of triangles. Our layouts can significantly reduce the number of cache misses. We have observed 2-20 times speedups in view-dependent rendering, collision detection, and isocontour extraction without any modification of the algorithms or runtime applications

User Manual for the PROTEUS Mesh Tools

Energy Technology Data Exchange (ETDEWEB)

Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, Emily R. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-06-01

This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial or .merge) can be used as “mesh” input for any of the mesh tools discussed in this manual.

Biologic meshes and synthetic meshes in cancer patients: a double-edged sword: differences in production of IL-6 and IL-12 caused by acellular dermal matrices in human immune cells.

Science.gov (United States)

Karsten, Maria Margarete; Enders, Sabine; Knabl, Julia; Kirn, Verena; Düwell, Peter; Rack, Brigitte; Blohmer, Jens-Uwe; Mayr, Doris; Dian, Darius

2018-05-01

In 2005, Breuing et al. first described the use of acellular dermal matrices (ADMs) in breast cancer patients. ADMs are assumed to be safe to use in an oncologic setting, but data from controlled studies are still needed. Here, we investigate the effects of ADMs on the production of interleukin (IL)-6 and IL-12, key regulators of immune suppression and activation. Strattice (ST), CollaMend (CM), and Biodesign (BD) biologic meshes and TiLoop, a synthetic mesh (TL), were used in this study. We isolated myeloid dendritic cells (MDCs), untouched plasmacytoid dendritic cells (pDCs), naïve B cells, and CD8+ T cells and co-cultured these cells with either the biologic meshes or TL. As positive controls, we used CpG ODN 2216 or lipopolysaccharide (LPS). The cytokine concentrations of IL-12p70 and IL-6 were determined after 7 days using sandwich ELISA sets. There were highly significant differences between the ADMs and TL in terms of their ability to stimulate immunologic responses. IL-6 expression was significantly increased in B cells (p = 0.0006131) and T cells (p = 0.00418) when comparing TL and ADMs. We also identified significant differences in IL-12 production by B cells (p = 0.0166) and T cells (p = 0.003636) when comparing TL and ADMs. Despite the assumed lack of an immunological response to ADMs, in our experimental study, human immune cells reacted with significantly different cytokine profiles. These findings may have implications for the potential activation or suppression of effector cells in cancer patients and could explain some of the post clinical post surgical signs of ADMS like skin rush and seroma.

6th International Meshing Roundtable '97

Energy Technology Data Exchange (ETDEWEB)

White, D.

1997-09-01

The goal of the 6th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the pas~ the Roundtable has enjoyed significant participation born each of these groups from a wide variety of countries. The Roundtable will consist of technical presentations from contributed papers and abstracts, two invited speakers, and two invited panels of experts discussing topics related to the development and use of automatic mesh generation tools. In addition, this year we will feature a "Bring Your Best Mesh" competition and poster session to encourage discussion and participation from a wide variety of mesh generation tool users. The schedule and evening social events are designed to provide numerous opportunities for informal dialog. A proceedings will be published by Sandia National Laboratories and distributed at the Roundtable. In addition, papers of exceptionally high quaIity will be submitted to a special issue of the International Journal of Computational Geometry and Applications. Papers and one page abstracts were sought that present original results on the meshing process. Potential topics include but are got limited to: Unstructured triangular and tetrahedral mesh generation Unstructured quadrilateral and hexahedral mesh generation Automated blocking and structured mesh generation Mixed element meshing Surface mesh generation Geometry decomposition and clean-up techniques Geometry modification techniques related to meshing Adaptive mesh refinement and mesh quality control Mesh visualization Special purpose meshing algorithms for particular applications Theoretical or novel ideas with practical potential Technical presentations from industrial researchers.

User Manual for the PROTEUS Mesh Tools

Energy Technology Data Exchange (ETDEWEB)

Smith, Micheal A. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, Emily R [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-09-19

PROTEUS is built around a finite element representation of the geometry for visualization. In addition, the PROTEUS-SN solver was built to solve the even-parity transport equation on a finite element mesh provided as input. Similarly, PROTEUS-MOC and PROTEUS-NEMO were built to apply the method of characteristics on unstructured finite element meshes. Given the complexity of real world problems, experience has shown that using commercial mesh generator to create rather simple input geometries is overly complex and slow. As a consequence, significant effort has been put into place to create multiple codes that help assist in the mesh generation and manipulation. There are three input means to create a mesh in PROTEUS: UFMESH, GRID, and NEMESH. At present, the UFMESH is a simple way to generate two-dimensional Cartesian and hexagonal fuel assembly geometries. The UFmesh input allows for simple assembly mesh generation while the GRID input allows the generation of Cartesian, hexagonal, and regular triangular structured grid geometry options. The NEMESH is a way for the user to create their own mesh or convert another mesh file format into a PROTEUS input format. Given that one has an input mesh format acceptable for PROTEUS, we have constructed several tools which allow further mesh and geometry construction (i.e. mesh extrusion and merging). This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT_MeshToMesh.x and the MT_RadialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial

Biologic mesh reconstruction of the pelvic floor after extralevator abdominoperineal excision; a systematic review

Directory of Open Access Journals (Sweden)

Nasra N Alam

2016-02-01

Full Text Available IntroductionThe aim of this review is to provide an overview of the evidence for the use of biologic mesh in the reconstruction of the pelvic floor after extralevator abdominoperineal excision of the rectum (ELAPE.MethodsA systematic search of PubMed was conducted using the search terms ‘ELAPE’, ‘extralevator abdominoperineal excision of rectum’ or ‘extralevator abdominoperineal resection’. The search yielded 17 studies.ResultsBiologic mesh was used in perineal reconstruction in 463 cases. There were 41 perineal hernias reported but rates were not consistently reported in all studies. The most common complications were perineal wound infection (n = 93, perineal sinus and fistulae (n = 26 and perineal haematoma or seroma (n = 11. There were very few comparative studies, with only one RCT identified that compared patients undergoing ELAPE with perineal reconstruction using a biological mesh, with patients undergoing a conventional abdominoperineal excision of the rectum with no mesh. There was no significant difference in perineal hernia rates or perineal wound infections between the groups. Other comparative studies comparing the use of biologic mesh with techniques such as the use of myocutaneous flaps were of low quality.ConclusionsBiologic mesh-assisted perineal reconstruction is a promising technique to improve wound healing and has comparable complications rates to other techniques. However, there is not enough evidence to support its use in all patients who have undergone ELAPE. Results from high-quality prospective RCTs and national/international collaborative audits are required.

User Manual for the PROTEUS Mesh Tools

International Nuclear Information System (INIS)

Smith, Micheal A.; Shemon, Emily R.

2015-01-01

This report describes the various mesh tools that are provided with the PROTEUS code giving both descriptions of the input and output. In many cases the examples are provided with a regression test of the mesh tools. The most important mesh tools for any user to consider using are the MT M eshToMesh.x and the MT R adialLattice.x codes. The former allows the conversion between most mesh types handled by PROTEUS while the second allows the merging of multiple (assembly) meshes into a radial structured grid. Note that the mesh generation process is recursive in nature and that each input specific for a given mesh tool (such as .axial or .merge) can be used as ''mesh'' input for any of the mesh tools discussed in this manual.

Effects of electromagnetic fields from mobile phones on depression and anxiety after titanium mesh cranioplasty among patients with traumatic brain injury.

Science.gov (United States)

Zhu, Yongjian; Jin, Wen; Liu, Hui; Peng, Deqing; Ding, Zheyuan; Tang, Zhuxiao; Zhu, Liangliang; Yu, Yunxian

2016-01-01

To explore the effects of radiofrequency-electromagnetic fields (RF-EMFs) from mobile phones on depression and anxiety after titanium mesh cranioplasty among patients with traumatic brain injury (TBI). Two hundred and twenty patients with TBI and titanium mesh cranioplasty who were hospitalized from 2008-2012 were recruited in this study. From November-December 2012, the relevant information was surveyed including socio-demographic characteristics, lifestyle variables, injury-related information, RF-EMF exposure of mobile phone, Self-rating Depression Scale (SDS) and Self-rating Anxiety Scale (SAS). Associations of RF-EMFs exposure after titanium mesh cranioplasty with SAS and SDS were respectively estimated by multivariable linear regression models. The patients with long durations of mobile phone use (β = -6.6, p = 0.002), long individual call duration (β = -5.3, p = 0.012), more daily calls (β = -3.6, p = 0.027), invariably answer call immediately (β = -3.9, p = 0.022) and high comprehensive exposure level (β = -4.8, p = 0.003) had a lower score of depression compared with those without a mobile phone. Moreover, an ipsilateral and contralateral answering phone enhanced the protective effect on depression. Individuals with a long duration of mobile phone use had a lower score of anxiety (β = -4.2, p = 0.008), while those with a bilateral answering phone had higher anxiety (β = 3.9, p = 0.012) in comparison to those without a mobile phone. RF-EMFs after cranioplasty were significantly associated with the lower risk of depression and anxiety status among patients with TBI. Chronic and frequent RF-EMFs exposure may improve psychiatric disorders among patients with TBI.

Streaming Compression of Hexahedral Meshes

Energy Technology Data Exchange (ETDEWEB)

Isenburg, M; Courbet, C

2010-02-03

We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

RGG: Reactor geometry (and mesh) generator

International Nuclear Information System (INIS)

Jain, R.; Tautges, T.

2012-01-01

The reactor geometry (and mesh) generator RGG takes advantage of information about repeated structures in both assembly and core lattices to simplify the creation of geometry and mesh. It is released as open source software as a part of the MeshKit mesh generation library. The methodology operates in three stages. First, assembly geometry models of various types are generated by a tool called AssyGen. Next, the assembly model or models are meshed by using MeshKit tools or the CUBIT mesh generation tool-kit, optionally based on a journal file output by AssyGen. After one or more assembly model meshes have been constructed, a tool called CoreGen uses a copy/move/merge process to arrange the model meshes into a core model. In this paper, we present the current state of tools and new features in RGG. We also discuss the parallel-enabled CoreGen, which in several cases achieves super-linear speedups since the problems fit in available RAM at higher processor counts. Several RGG applications - 1/6 VHTR model, 1/4 PWR reactor core, and a full-core model for Monju - are reported. (authors)

Ventral incisional hernia (VIH) repair after liver transplantation (OLT) with a biological mesh: experience in 3 cases.

Science.gov (United States)

Schaffellner, S; Sereinigg, M; Wagner, D; Jakoby, E; Kniepeiss, D; Stiegler, P; Haybäck, J; Müller, H

2016-05-01

Hernias after orthotopic liver transplant (OLT) occur in about 30 % of cases. Predisposing factors in liver cirrhotic patients of cases are ascites, low abdominal muscle mass and cachexia before and immunosuppression after OLT. Standard operative transplant-technique even in small hernias is to implant a mesh. For patients after liver transplantation a porcine non-cross linked biological patch being less immunogenic than synthetic and cross-linked meshes is chosen for ventral incisional hernia repair. 3 patients (1 female, 2 male), OLT indications Hepatitis C, exogenous- toxic cirrhosis, median-age 53 (51 - 56) and median time to hernia occurrence after OLT were 10 month (6 - 18 m) are documented. 2 patients suffered from diabetes, 2 from chronic-obstructive lung disease. Maintenance immunosuppressions were Everolimus in 1 patient, Everolimus + MMF in the second and Everolimus +Tacrolimus in the third patient. The biological was chosen for hernia repair due to the preexisting risk- factors. Meshes, 10 × 16 cm were placed, in IPOM (Intra-Peritonel-Onlay-Mesh) -position by relaparatomy. Insolvable, monofile, interrupted sutures were used. All patients recovered primarily, and were dismissed within 10 d post OP. No wound healing disorders or signs of postoperative infections occurred. All are free of hernia recurrence in a mean observation time of 22 month (10 - 36). The usage of porcine non-cross-linked biological patches seems feasible for incisional hernia repair after OLT. Wound infections in these patients have been observed with other meshes. Further investigation is needed to prove potential superiority of this biological to the other meshes. © Georg Thieme Verlag KG Stuttgart · New York.

Properties of meshes used in hernia repair: a comprehensive review of synthetic and biologic meshes.

Science.gov (United States)

Ibrahim, Ahmed M S; Vargas, Christina R; Colakoglu, Salih; Nguyen, John T; Lin, Samuel J; Lee, Bernard T

2015-02-01

Data on the mechanical properties of the adult human abdominal wall have been difficult to obtain rendering manufacture of the ideal mesh for ventral hernia repair a challenge. An ideal mesh would need to exhibit greater biomechanical strength and elasticity than that of the abdominal wall. The aim of this study is to quantitatively compare the biomechanical properties of the most commonly used synthetic and biologic meshes in ventral hernia repair and presents a comprehensive literature review. A narrative review of the literature was performed using the PubMed database spanning articles from 1982 to 2012 including a review of company Web sites to identify all available information relating to the biomechanical properties of various synthetic and biologic meshes used in ventral hernia repair. There exist differences in the mechanical properties and the chemical nature of different meshes. In general, most synthetic materials have greater stiffness and elasticity than what is required for abdominal wall reconstruction; however, each exhibits unique properties that may be beneficial for clinical use. On the contrary, biologic meshes are more elastic but less stiff and with a lower tensile strength than their synthetic counterparts. The current standard of practice for the treatment of ventral hernias is the use of permanent synthetic mesh material. Recently, biologic meshes have become more frequently used. Most meshes exhibit biomechanical properties over the known abdominal wall thresholds. Augmenting strength requires increasing amounts of material contributing to more stiffness and foreign body reaction, which is not necessarily an advantage. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Temporary abdominal closure with zipper-mesh device for management of intra-abdominal sepsis

Directory of Open Access Journals (Sweden)

Edivaldo Massazo Utiyama

Full Text Available OBJECTIVE: to present our experience with scheduled reoperations in 15 patients with intra-abdominal sepsis. METHODS: we have applied a more effective technique consisting of temporary abdominal closure with a nylon mesh sheet containing a zipper. We performed reoperations in the operating room under general anesthesia at an average interval of 84 hours. The revision consisted of debridement of necrotic material and vigorous lavage of the involved peritoneal area. The mean age of patients was 38.7 years (range, 15 to 72 years; 11 patients were male, and four were female. RESULTS: forty percent of infections were due to necrotizing pancreatitis. Sixty percent were due to perforation of the intestinal viscus secondary to inflammation, vascular occlusion or trauma. We performed a total of 48 reoperations, an average of 3.2 surgeries per patient. The mesh-zipper device was left in place for an average of 13 days. An intestinal ostomy was present adjacent to the zipper in four patients and did not present a problem for patient management. Mortality was 26.6%. No fistulas resulted from this technique. When intra-abdominal disease was under control, the mesh-zipper device was removed, and the fascia was closed in all patients. In three patients, the wound was closed primarily, and in 12 it was allowed to close by secondary intent. Two patients developed hernia; one was incisional and one was in the drain incision. CONCLUSION: the planned reoperation for manual lavage and debridement of the abdomen through a nylon mesh-zipper combination was rapid, simple, and well-tolerated. It permitted effective management of severe septic peritonitis, easy wound care and primary closure of the abdominal wall.

Towards a real time computation of the dose in a phantom segmented into homogeneous meshes

International Nuclear Information System (INIS)

Blanpain, B.

2009-10-01

Automatic radiation therapy treatment planning necessitates a very fast computation of the dose delivered to the patient. We propose to compute the dose by segmenting the patient's phantom into homogeneous meshes, and by associating, to the meshes, projections to dose distributions pre-computed in homogeneous phantoms, along with weights managing heterogeneities. The dose computation is divided into two steps. The first step impacts the meshes: projections and weights are set according to physical and geometrical criteria. The second step impacts the voxels: the dose is computed by evaluating the functions previously associated to their mesh. This method is very fast, in particular when there are few points of interest (several hundreds). In this case, results are obtained in less than one second. With such performances, practical realization of automatic treatment planning becomes practically feasible. (author)

Open tension-free hernioplasty using a novel lightweight self-gripping mesh: medium-term experience from two institutions.

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Pedano, Nicolás; Pastor, Carlos; Arredondo, Jorge; Poveda, Ignacio; Ruiz, Jaime; Montón, Soledad; Molina, María; Hernández-Lizoain, José Luis

2012-02-01

The process of mesh fixation and the potential risk of associated chronic pain are always surgeon's main concerns in hernia surgery. A wide variety of lightweight mesh models are currently available on the market to overcome some of these problems showing good preliminary results, but no data representing the medium- or long-term results. The present study aims to report the clinical outcomes of two institutional series of patients who underwent hernia repair using a partially absorbable auto adherent mesh (Parietene™ Progrip™--PP). A prospective analysis was performed including unselected patients with primary groin hernia who underwent a standardized Lichtenstein procedure using the PP mesh at two tertiary institutions. During the 2-year study period, 181 patients (167 males; 14 females) with a median age of 63 years (19-85 years) were operated on at both centers. Short-term complications occurred in 27 patients (15%), the most commonly seen being urinary retention (6%) followed by hematoma (5%) and acute orchitis (2%). With a median follow-up of 17 months (12-29 months), 4 patients (2%) had a feeling of a foreign body in the groin, and 7 (4%) developed chronic pain. A total of four patients (2%) developed recurrence. In our experience, the use of the PP mesh for hernioplasties offers a potential benefit not only in the short-term period but also in a medium-term follow-up with low recurrence and late chronic pain rates. However, this particular mesh does not fully prevent all complications and chronic pain and recurrent hernias have been reported for the first time.

Sierra toolkit computational mesh conceptual model

International Nuclear Information System (INIS)

Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.

2010-01-01

The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

Parallel 3D Mortar Element Method for Adaptive Nonconforming Meshes

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Feng, Huiyu; Mavriplis, Catherine; VanderWijngaart, Rob; Biswas, Rupak

2004-01-01

High order methods are frequently used in computational simulation for their high accuracy. An efficient way to avoid unnecessary computation in smooth regions of the solution is to use adaptive meshes which employ fine grids only in areas where they are needed. Nonconforming spectral elements allow the grid to be flexibly adjusted to satisfy the computational accuracy requirements. The method is suitable for computational simulations of unsteady problems with very disparate length scales or unsteady moving features, such as heat transfer, fluid dynamics or flame combustion. In this work, we select the Mark Element Method (MEM) to handle the non-conforming interfaces between elements. A new technique is introduced to efficiently implement MEM in 3-D nonconforming meshes. By introducing an "intermediate mortar", the proposed method decomposes the projection between 3-D elements and mortars into two steps. In each step, projection matrices derived in 2-D are used. The two-step method avoids explicitly forming/deriving large projection matrices for 3-D meshes, and also helps to simplify the implementation. This new technique can be used for both h- and p-type adaptation. This method is applied to an unsteady 3-D moving heat source problem. With our new MEM implementation, mesh adaptation is able to efficiently refine the grid near the heat source and coarsen the grid once the heat source passes. The savings in computational work resulting from the dynamic mesh adaptation is demonstrated by the reduction of the the number of elements used and CPU time spent. MEM and mesh adaptation, respectively, bring irregularity and dynamics to the computer memory access pattern. Hence, they provide a good way to gauge the performance of computer systems when running scientific applications whose memory access patterns are irregular and unpredictable. We select a 3-D moving heat source problem as the Unstructured Adaptive (UA) grid benchmark, a new component of the NAS Parallel

Comparison of computed tomography based parametric and patient-specific finite element models of the healthy and metastatic spine using a mesh-morphing algorithm.

Science.gov (United States)

O'Reilly, Meaghan Anne; Whyne, Cari Marisa

2008-08-01

A comparative analysis of parametric and patient-specific finite element (FE) modeling of spinal motion segments. To develop patient-specific FE models of spinal motion segments using mesh-morphing methods applied to a parametric FE model. To compare strain and displacement patterns in parametric and morphed models for both healthy and metastatically involved vertebrae. Parametric FE models may be limited in their ability to fully represent patient-specific geometries and material property distributions. Generation of multiple patient-specific FE models has been limited because of computational expense. Morphing methods have been successfully used to generate multiple specimen-specific FE models of caudal rat vertebrae. FE models of a healthy and a metastatic T6-T8 spinal motion segment were analyzed with and without patient-specific material properties. Parametric and morphed models were compared using a landmark-based morphing algorithm. Morphing of the parametric FE model and including patient-specific material properties both had a strong impact on magnitudes and patterns of vertebral strain and displacement. Small but important geometric differences can be represented through morphing of parametric FE models. The mesh-morphing algorithm developed provides a rapid method for generating patient-specific FE models of spinal motion segments.

Transvaginal repair of genital prolapse: preliminary results of a new tension-free vaginal mesh (Prolift technique)--a case series multicentric study.

Science.gov (United States)

Fatton, B; Amblard, J; Debodinance, P; Cosson, M; Jacquetin, B

2007-07-01

Our goal was to report the preliminary results of a transvaginal mesh repair of genital prolapse using the Prolift system. This retrospective multicentric study includes 110 patients. All patients had a stage 3 (at the hymen) or stage 4 (beyond the hymen) prolapse. Total mesh was used in 59 patients (53.6%), an isolated anterior mesh in 22 patients (20%) and an isolated posterior mesh in 29 patients (26.4%). We report one bladder injury sutured at surgery and two haematomas requiring secondary surgical management. At 3 months, 106 patients were available for follow-up. Mesh exposure occurred in five patients (4.7%), two of them requiring a surgical management. Granuloma without exposure occurred in three patients (2.8%). Failure rate (recurrent prolapse even asymptomatic or low grade symptomatic prolapse) was 4.7%. According to the perioperative and immediate post-operative results, Prolift repair seems to be a safe technique to correct pelvic organ prolapse. Anatomical and functional results must be assessed with a long-term follow-up to confirm the effectiveness and safety of the procedure.

Energy Efficient Monitoring for Intrusion Detection in Battery-Powered Wireless Mesh Networks

KAUST Repository

Hassanzadeh, Amin

2011-07-18

Wireless Mesh Networks (WMN) are easy-to-deploy, low cost solutions for providing networking and internet services in environments with no network infrastructure, e.g., disaster areas and battlefields. Since electric power is not readily available in such environments battery-powered mesh routers, operating in an energy efficient manner, are required. To the best of our knowledge, the impact of energy efficient solutions, e.g., involving duty-cycling, on WMN intrusion detection systems, which require continuous monitoring, remains an open research problem. In this paper we propose that carefully chosen monitoring mesh nodes ensure continuous and complete detection coverage, while allowing non-monitoring mesh nodes to save energy through duty-cycling. We formulate the monitoring node selection problem as an optimization problem and propose distributed and centralized solutions for it, with different tradeoffs. Through extensive simulations and a proof-of-concept hardware/software implementation we demonstrate that our solutions extend the WMN lifetime by 8%, while ensuring, at the minimum, a 97% intrusion detection rate.

Textile properties of synthetic prolapse mesh in response to uniaxial loading

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Barone, William R.; Moalli, Pamela A.; Abramowitch, Steven D.

2016-01-01

, with values decreasing by as much as 87% (P mesh products that were tested were found to have porosities that approached 0% and 0 pores with diameters >1 mm. CONCLUSION In this study, it was shown that the pore size of current prolapse meshes dramatically decreases in response to mechanical loading. These findings suggest that prolapse meshes, which are more likely to experience tensile forces in vivo relative to hernia repair meshes, have pores that are unfavorable for tissue integration after surgical tensioning and/or loading in urogynecologic surgeries. Such decreases in pore geometry support the hypothesis that regional increases in the concentration of mesh leads to an enhanced local foreign body response. Although pore deformation in transvaginal meshes requires further characterization, the findings presented here provide a mechanical understanding that can be used to recognize potential areas of concern for complex mesh geometries. Understanding mesh mechanics in response to surgical and in vivo loading conditions may provide improved design criteria for mesh and a refinement of surgical techniques, ultimately leading to better patient outcomes. PMID:27001219

From 4D Medical Images (CT, MRI, and Ultrasound to 4D Structured Mesh Models of the Left Ventricular Endocardium for Patient-Specific Simulations

Directory of Open Access Journals (Sweden)

Federico Canè

2018-01-01

Full Text Available With cardiovascular disease (CVD remaining the primary cause of death worldwide, early detection of CVDs becomes essential. The intracardiac flow is an important component of ventricular function, motion kinetics, wash-out of ventricular chambers, and ventricular energetics. Coupling between Computational Fluid Dynamics (CFD simulations and medical images can play a fundamental role in terms of patient-specific diagnostic tools. From a technical perspective, CFD simulations with moving boundaries could easily lead to negative volumes errors and the sudden failure of the simulation. The generation of high-quality 4D meshes (3D in space + time with 1-to-1 vertex becomes essential to perform a CFD simulation with moving boundaries. In this context, we developed a semiautomatic morphing tool able to create 4D high-quality structured meshes starting from a segmented 4D dataset. To prove the versatility and efficiency, the method was tested on three different 4D datasets (Ultrasound, MRI, and CT by evaluating the quality and accuracy of the resulting 4D meshes. Furthermore, an estimation of some physiological quantities is accomplished for the 4D CT reconstruction. Future research will aim at extending the region of interest, further automation of the meshing algorithm, and generating structured hexahedral mesh models both for the blood and myocardial volume.

Long-term outcome after transvaginal mesh repair of pelvic organ prolapse.

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Heinonen, Pia; Aaltonen, Riikka; Joronen, Kirsi; Ala-Nissilä, Seija

2016-07-01

The aim of this study was to report long-term subjective and objective outcomes after the transvaginal mesh (TVM) procedure in long-term. Possible late-onset complications were of particular interest. This was a retrospective analysis of TVM performed using Prolift™ transvaginal mesh measuring subjective outcome using validated questionnaires. Objective outcome was assessed using the Pelvic Organ Prolapse Quantification (POP-Q) system using two definitions: POP-Q stage ≤ 1, and vaginal wall prolapse at or above the hymen or vaginal apex not descending below the upper third of the vagina. Complications were reported with the Prosthesis/Graft Complication Classification Code designed by the International Continence Society/International Urogynecological Association (ICS/IUGA). Of 195 patients, 161 (82.6 %) participated this study after a median of 7 years. The scores in questionnaires evaluating urinary (UI) or anal incontinence and constipation or pelvic floor symptoms were low, indicating favorable surgical outcomes. Altogether, 80.1 % of patients were satisfied with the procedure. Anatomical cure was 56.4 % and 69.3 % depending on the definition used. Reoperation due to POP in any compartment was performed in 16.2 % of patients. Mesh exposure rate was 23 %, most of these being asymptomatic and of late onset. Outcome of the TVM procedure was satisfactory. Anatomical cure was inferior to subjective cure. Mesh exposure rate was high; most exposures observed in the long-term were of late onset and were asymptomatic.

SLIC: an interactive mesh generator for finite element and finite difference application programs

International Nuclear Information System (INIS)

Gerhard, M.A.; Greenlaw, R.C.

1979-01-01

Computers with extended memory, such as the CDC STAR 100 and the CRAY 1 with mega-word capacities, are greatly enlarging the size of finite element problems which can be solved. The cost of developing and testing large meshes can be prohibitive unless one uses a computer program for mesh generation and plotting. SLIC is an interactive mesh program which builds and plots 2- and 3-D continuum meshes from interactive terminal or disc input. The user inputs coordinates for certain key points and enters commands which complete the description of the geometry. Entire surfaces and volumes are then generated from the geometric skeleton. SLIC allows the user to correct input errors and saves the corrected command list for later reuse. The mesh can be plotted on a video display at any stage of development to evaluate the work in progress. Output is in the form of an input file to a user-selected computer code. Among the available output types are ADINA, SAP4, and NIKE2D. 11 figures

Transvaginal mesh in the media following the 2011 US food and drug administration public health notification update.

Science.gov (United States)

Koo, Kevin; Gormley, E Ann

2017-02-01

Prompted by patients' changing perceptions of transvaginal mesh, this study examines how mesh has been reported in the news following the 2011 US Food and Drug Administration (FDA) updated notification about the use of mesh in the treatment of pelvic organ prolapse. Two national newspaper databases were queried for articles discussing transvaginal mesh published within 3 years of the FDA announcement. Content analysis included headline subjects, mesh-related complications, quoted sources, and the FDA recommendations. To determine whether more widely read sources publish higher quality reporting, a subgroup analysis was conducted based on newspaper circulation. Ninety-five articles met inclusion criteria. Mesh-related litigation was the most common headline subject (36 articles, 38%), and 54% of all articles referenced legal action. Fifty-seven articles (60%) cited at least one mesh-related complication. Only 18 articles (19%) quoted surgeons who use transvaginal mesh. For the FDA update, 40% of articles that first reported the announcement accurately specified that it applies to mesh for prolapse, not incontinence. This ambiguity persisted: half of all articles cited the warning, but only 23% distinguished between prolapse and incontinence. Higher newspaper circulation did not significantly improve the quality of reporting about the content or context of the FDA's recommendations. Despite frequent media coverage of transvaginal mesh and its complications since 2011, very few news sources that cited the FDA warning distinguished between prolapse and incontinence. Given prevalent reporting of mesh-related litigation, the findings raise concern about how patients perceive the safety and efficacy of transvaginal mesh, regardless of indication. Neurourol. Urodynam. 36:329-332, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Anterior colporrhaphy versus transvaginal mesh for pelvic-organ prolapse.

Science.gov (United States)

Altman, Daniel; Väyrynen, Tapio; Engh, Marie Ellström; Axelsen, Susanne; Falconer, Christian

2011-05-12

The use of standardized mesh kits for repair of pelvic-organ prolapse has spread rapidly in recent years, but it is unclear whether this approach results in better outcomes than traditional colporrhaphy. In this multicenter, parallel-group, randomized, controlled trial, we compared the use of a trocar-guided, transvaginal polypropylene-mesh repair kit with traditional colporrhaphy in women with prolapse of the anterior vaginal wall (cystocele). The primary outcome was a composite of the objective anatomical designation of stage 0 (no prolapse) or 1 (position of the anterior vaginal wall more than 1 cm above the hymen), according to the Pelvic Organ Prolapse Quantification system, and the subjective absence of symptoms of vaginal bulging 12 months after the surgery. Of 389 women who were randomly assigned to a study treatment, 200 underwent prolapse repair with the transvaginal mesh kit and 189 underwent traditional colporrhaphy. At 1 year, the primary outcome was significantly more common in the women treated with transvaginal mesh repair (60.8%) than in those who underwent colporrhaphy (34.5%) (absolute difference, 26.3 percentage points; 95% confidence interval, 15.6 to 37.0). The surgery lasted longer and the rates of intraoperative hemorrhage were higher in the mesh-repair group than in the colporrhaphy group (Pmesh-repair group and 0.5% in the colporrhaphy group (P=0.07), and the respective rates of new stress urinary incontinence after surgery were 12.3% and 6.3% (P=0.05). Surgical reintervention to correct mesh exposure during follow-up occurred in 3.2% of 186 patients in the mesh-repair group. As compared with anterior colporrhaphy, use of a standardized, trocar-guided mesh kit for cystocele repair resulted in higher short-term rates of successful treatment but also in higher rates of surgical complications and postoperative adverse events. (Funded by the Karolinska Institutet and Ethicon; ClinicalTrials.gov number, NCT00566917.).

Hybrid NOTES transvaginal intraperitoneal onlay mesh in abdominal wall hernias: an alternative to traditional laparoscopic procedures.

Science.gov (United States)

Descloux, Alexandre; Pohle, Sebastian; Nocito, Antonio; Keerl, Andreas

2015-12-01

Abdominal wall hernias are increasingly treated by laparoscopic placement of an intraperitoneal onlay mesh (IPOM). We present an alternative technique for women: the laparoscopic-assisted transvaginal IPOM. Before surgery, all patients underwent a gynecological examination. The patients agreed to IPOM repair via a transvaginal approach, and written informed consent for surgery was obtained. Pneumoperitoneum was established with a Veress needle at the umbilicus. This access was subsequently dilated to 5 mm (VersaStep), and a 5-mm laparoscope was inserted. Under laparoscopic view, the transvaginal trocars (12-mm VersaStep and 5-mm flexible accesses) were safely inserted after lifting the uterus with a uterus manipulator. After preparation of the falciform ligament, the ligamentum teres and the preperitoneal fat, a lightweight composite mesh was introduced through the transvaginal access and fixed with absorbable tacks using the double-crown technique. From September 2011 to December 2012, we performed six laparoscopic-assisted transvaginal IPOM procedures (one epigastric, three umbilical, two combined epigastric and umbilical hernias; all were primary hernias). In the initial phase, only patients with small or medium primary abdominal wall hernia were selected (max. 3 cm diameter). Median hospital stay was 3 days (range 2-6 days). One minor complication occurred perioperatively (second-degree skin burn to the labia majora). At 1-year follow-up, we identified one recurrence in a high-risk patient with a body mass index higher than 35 kg/m(2). No infection and no mortality were observed. Although no final conclusion can be made regarding the presumed non-inferiority of this technique in terms of recurrence and mesh infection compared with traditional laparoscopic IPOM, laparoscopic-assisted transvaginal IPOM is a feasible alternative to treat abdominal wall hernias.

Road to recovery after transvaginal surgery for urethral mesh perforation: evaluation of outcomes and subsequent procedures.

Science.gov (United States)

Kowalik, Casey G; Cohn, Joshua A; Kakos, Andrea; Lang, Patrick; Reynolds, W Stuart; Kaufman, Melissa R; Karram, Mickey M; Dmochowski, Roger R

2018-01-29

Urethral injury resulting from transvaginal mesh slings is a rare complication with an estimated incidence of surgical management and functional outcomes of women presenting with urethral mesh perforation following midurethral sling (MUS) placement. This was a retrospective multicenter review of women who from January 2011 to March 2016 at two institutions underwent mesh sling excision for urethral perforation with Female Pelvic Medicine and Reconstructive Surgery fellowship-trained surgeons. Data comprising preoperative symptoms, operative details, and postoperative outcomes were collected by telephone (n 13) or based on their last follow-up appointment. Nineteen women underwent transvaginal sling excision for urethral mesh perforation. Eight (42%) patients had undergone previous sling revision surgery. Sixty percent of women had resolution of their pelvic pain postoperatively. At follow-up, 92% reported urinary incontinence (UI), and three had undergone five additional procedures for vaginal prolapse mesh exposure (n 1), incontinence (onabotulinum toxin injection n 1, rectus fascia autologous sling n 1), prolapse (colpopexy n 1), and pain (trigger-point injection n 1). Patient global impression of improvement data was available for 13 patients, of whom seven (54%) rated their postoperative condition as Very much better or Much better. The management of urethral mesh perforation is complex. Most women reported resolution of their pelvic pain and a high rate of satisfaction with their postoperative condition despite high rates of incontinence.

Transvaginal Resection of an Infected Sacrocolpopexy Mesh by Single-Port Trocar.

Science.gov (United States)

Schaub, Marie; Lecointre, Lise; Faller, Emilie; Boisramé, Thomas; Baldauf, Jean-Jacques; Akladios, Cherif Youssef

Laparoscopy using a single port improves morbidity while keeping the same level of requirement. This technique has been evaluated in gynecology for salpingectomy, ovarian surgery, and hysterectomy. Here, the authors illustrate a new use of a single port using the transvaginal approach. Case report (Canadian Task Force classification III). Tertiary referral center in Strasbourg, France. Woman age 59 years. Single-port platform used in the transvaginal approach for resection of sacrocolpopexy mesh. The local institutional review board approved the video. A 59-year-old woman suffering from insulin-dependent diabetes and a tobacco user had 2 laparoscopic sacrocolpopexies for recurrent rectocele, the first in 2007 and the second in 2012. The sequences were marked by mesh erosion and granuloma in the vagina, requiring its surgical excision in 2016. The patient was then symptomatic, with an increasingly foul-smelling vaginal discharge with recurrent mesh erosion. Magnetic resonance imaging showed an abscess formation along the length of the mesh to the promontory. The patient then underwent surgery, realized under probabilistic antibiotic therapy, consisting of complete excision of the sacrocolpopexy mesh by the transvaginal approach. After putting the single-port trocar (GelPoint; Applied Medical, Rancho Santa Margarita, CA) into the vagina and obtaining distension with the insufflator (AirSeal; Conmed, Utica, NY), classic laparoscopic instruments were introduced by the single-port trocar. The mesh was entirely resected in the retroperitoneal space. Mesh was again used because the exposed space is almost always surrounded by loose granulation tissue that facilitates dissection and also prevents injury to adjacent structures such as bladder, rectum, and peritoneum. Moreover, the opening of adjacent structures will manifest gas leaks and, consequently, loss of the pneumovagina. At the end of procedure, the vagina is not closed to permit optimal drainage with a multitubular

Short term post-operative morphing of sacrocolpopexy mesh measured by magnetic resonance imaging.

Science.gov (United States)

Sindhwani, Nikhil; Callewaert, Geertje; Deprest, Thomas; Housmans, Susanne; Van Beckevoort, Dirk; Deprest, Jan

2018-04-01

Sacrocolpopexy (SC) involves suspension of the vaginal vault or cervix to the sacrum using a mesh. Following insertion, the meshes have been observed to have undergone dimensional changes. To quantify dimensional changes of meshes following implantation and characterize their morphology in-vivo. 24 patients underwent SC using PolyVinyliDeneFluoride mesh loaded with Fe 3 O 4 particles. Tailored anterior and posterior mesh flaps were sutured to the respective vaginal walls, uniting at the apex. The posterior flap continued to the sacrum and was attached there. Meshes were visualized on magnetic resonance (MR) imaging at 12 [3-12] (median [range]) months postoperatively and 3D models of the mesh were generated. Dynamic MR sequences were acquired during valsalva to record mesh mobility. The area of the vagina effectively supported by the mesh (Effective Support Area (ESA)) was calculated. The 3D models' wall thickness map was analyzed to identify the locations of mesh folding. Intraclass correlation (ICC) was calculated to test the reliability of the methods. To measure the laxity and flatness of the mesh, the curvature and the ellipticity of the sacral flap were calculated. The ESA calculation methodology had ICC = 0.97. A reduction of 75.49 [61.55-78.67] % (median [IQR]) in area, 47.64 [38.07-59.81] % in anterior flap, and of 23.95 [10.96-27.21] % in the posterior flap was measured. The mesh appeared thicker near its attachment at the sacral promontory (n = 19) and near the vaginal apex (n = 22). The laxity of the mesh was 1.13 [1.10-1.16] and 60.55 [49.76-76.25] % of the sacral flap was flat. We could not reliably measure mesh mobility (ICC = 0.16). A methodology for complete 3D characterization of SC meshes using MR images was presented. After implantation, the supported area is much lower than what is prepared prior to implantation. We propose this happened during the surgery itself. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prophylactic mesh at end-colostomy construction reduces parastomal hernia rate: a randomized trial.

Science.gov (United States)

Lambrecht, J R; Larsen, S G; Reiertsen, O; Vaktskjold, A; Julsrud, L; Flatmark, K

2015-10-01

Parastomal hernia (PSH) is the most common complication of an end-colostomy and about one-quarter of patients need operative repair, which is often unsuccessful. A randomized trial was carried out to compare the results of using mesh or no mesh at the time of formation of a colostomy with the clinical identification of PSH as the primary outcome. In this two-centre randomized trial (Oslo University Hospital and Sykehuset Innlandet Hospital Trust, Norway), patients with rectal cancer undergoing open pelvic surgery were randomized to receive a retromuscular synthetic mesh (study group, n = 32) or no mesh (control group, n = 26) at the time of end-colostomy formation. Postoperative follow up was not blinded and included clinical examination and routine CT. The median period of follow up was 40 (range: 84) months. There were no differences in demographic variables or complications between the study and control groups. PSH developed in two patients of the study group and in 12 of the control group [OR = 0.04 (95% CI: 0.01-0.30) and hazard ratio 0.134 (95% CI: 0.030-0.603); P colostomy reduced the risk of PSH. Colorectal Disease © 2015 The Association of Coloproctology of Great Britain and Ireland.

Method and system for mesh network embedded devices

Science.gov (United States)

Wang, Ray (Inventor)

2009-01-01

A method and system for managing mesh network devices. A mesh network device with integrated features creates an N-way mesh network with a full mesh network topology or a partial mesh network topology.

Fog water collection effectiveness: Mesh intercomparisons

Science.gov (United States)

Fernandez, Daniel; Torregrosa, Alicia; Weiss-Penzias, Peter; Zhang, Bong June; Sorensen, Deckard; Cohen, Robert; McKinley, Gareth; Kleingartner, Justin; Oliphant, Andrew; Bowman, Matthew

2018-01-01

To explore fog water harvesting potential in California, we conducted long-term measurements involving three types of mesh using standard fog collectors (SFC). Volumetric fog water measurements from SFCs and wind data were collected and recorded in 15-minute intervals over three summertime fog seasons (2014–2016) at four California sites. SFCs were deployed with: standard 1.00 m2 double-layer 35% shade coefficient Raschel; stainless steel mesh coated with the MIT-14 hydrophobic formulation; and FogHa-Tin, a German manufactured, 3-dimensional spacer fabric deployed in two orientations. Analysis of 3419 volumetric samples from all sites showed strong relationships between mesh efficiency and wind speed. Raschel mesh collected 160% more fog water than FogHa-Tin at wind speeds less than 1 m s–1 and 45% less for wind speeds greater than 5 m s–1. MIT-14 coated stainless-steel mesh collected more fog water than Raschel mesh at all wind speeds. At low wind speeds of steel mesh collected 3% more and at wind speeds of 4–5 m s–1, it collected 41% more. FogHa-Tin collected 5% more fog water when the warp of the weave was oriented vertically, per manufacturer specification, than when the warp of the weave was oriented horizontally. Time series measurements of three distinct mesh across similar wind regimes revealed inconsistent lags in fog water collection and inconsistent performance. Since such differences occurred under similar wind-speed regimes, we conclude that other factors play important roles in mesh performance, including in-situ fog event and aerosol dynamics that affect droplet-size spectra and droplet-to-mesh surface interactions.

Meshes optimized for discrete exterior calculus (DEC).

Energy Technology Data Exchange (ETDEWEB)

Mousley, Sarah C. [Univ. of Illinois, Urbana-Champaign, IL (United States); Deakin, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knupp, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

We study the optimization of an energy function used by the meshing community to measure and improve mesh quality. This energy is non-traditional because it is dependent on both the primal triangulation and its dual Voronoi (power) diagram. The energy is a measure of the mesh's quality for usage in Discrete Exterior Calculus (DEC), a method for numerically solving PDEs. In DEC, the PDE domain is triangulated and this mesh is used to obtain discrete approximations of the continuous operators in the PDE. The energy of a mesh gives an upper bound on the error of the discrete diagonal approximation of the Hodge star operator. In practice, one begins with an initial mesh and then makes adjustments to produce a mesh of lower energy. However, we have discovered several shortcomings in directly optimizing this energy, e.g. its non-convexity, and we show that the search for an optimized mesh may lead to mesh inversion (malformed triangles). We propose a new energy function to address some of these issues.

Adaptive hybrid mesh refinement for multiphysics applications

International Nuclear Information System (INIS)

Khamayseh, Ahmed; Almeida, Valmor de

2007-01-01

The accuracy and convergence of computational solutions of mesh-based methods is strongly dependent on the quality of the mesh used. We have developed methods for optimizing meshes that are comprised of elements of arbitrary polygonal and polyhedral type. We present in this research the development of r-h hybrid adaptive meshing technology tailored to application areas relevant to multi-physics modeling and simulation. Solution-based adaptation methods are used to reposition mesh nodes (r-adaptation) or to refine the mesh cells (h-adaptation) to minimize solution error. The numerical methods perform either the r-adaptive mesh optimization or the h-adaptive mesh refinement method on the initial isotropic or anisotropic meshes to equidistribute weighted geometric and/or solution error function. We have successfully introduced r-h adaptivity to a least-squares method with spherical harmonics basis functions for the solution of the spherical shallow atmosphere model used in climate modeling. In addition, application of this technology also covers a wide range of disciplines in computational sciences, most notably, time-dependent multi-physics, multi-scale modeling and simulation

Comparative efficacy of Prolene and Prolene-Vicryl composite mesh for experimental ventral hernia repair in dogs.

Science.gov (United States)

Anjum, H; Bokhari, S G; Khan, M A; Awais, M; Mughal, Z U; Shahzad, H K; Ijaz, F; Siddiqui, M I; Khan, I U; Chaudhry, A S; Akhtar, R; Aslam, S; Akbar, H; Asif, M; Maan, M K; Khan, M A; Noor, A; Khan, W A; Ullah, A; Hayat, M A

2016-01-01

In this study, efficacy of two hernia mesh implants viz. conventional Prolene and a novel Prolene-Vicryl composite mesh was assessed for experimental ventral hernia repair in dogs. Twelve healthy mongrel dogs were selected and randomly divided into three groups, A, Band C (n=4). In all groups, an experimental laparotomy was performed; thereafter, the posterior rectus sheath and peritoneum were sutured together, while, a 5 × 5 cm defect was created in the rectus muscle belly and anterior rectus sheath. For sublay hernioplasty, the hernia mesh (Prolene: group A; Prolene-Vicryl composite mesh: group B), was implanted over the posterior rectus sheath. In group C (control), mesh was not implanted; instead the laparotomy incision was closed after a herniorrhaphy. Post-operative pain, mesh shrinkage and adhesion formation were assessed as short term complications. Post-operatively, pain at surgical site was significantly less (P<0.001) in group B (composite mesh); mesh shrinkage was also significantly less in group B (21.42%, P<0.05) than in group A (Prolene mesh shrinkage: 58.18%). Group B (composite mesh) also depicted less than 25% adhesions (Mean ± SE: 0.75 ± 0.50 scores, P≤0.013) when assessed on the basis of a Quantitative Modified Diamond scale; a Qualitative Adhesion Tenacity scale also depicted either no adhesions (n=2), or, only flimsy adhesions (n=2) in group B (composite mesh), in contrast to group A (Prolene), which manifested greater adhesion formation and presence of dense adhesions requiring blunt dissection. Conclusively, the Prolene-Vicryl composite mesh proved superior to the Prolene mesh regarding lesser mesh contraction, fewer adhesions and no short-term follow-up complications.

Stapled Mesh stomA Reinforcement Technique (SMART) in the prevention of parastomal hernia: a single-centre experience.

Science.gov (United States)

Ng, Z Q; Tan, P; Theophilus, M

2017-06-01

Parastomal hernia remains a frequent complication following creation of an abdominal stoma. Previous interests have centred around the exploration of methods to repair; however, prophylactic mesh placement has demonstrated its efficacy in reduction of parastomal hernia. The aim of this retrospective analysis was to evaluate the outcomes of Stapled Mesh stomA Reinforcement Technique (SMART) in terms of parastomal hernia occurrence rate and mesh-related complications. All patients operated with an abdominal perineal resection or Hartmann's procedure with SMART from November 2013 to March 2016 were included. Patient demographics, operative details and stoma-related symptoms were collected. Patients were examined clinically by the medical team and also reviewed independently by a specialist stoma care nurse for signs of stoma-related complications. As part of oncological follow-up, CT scans were available for review for evidence of parastomal herniation. 14 patients (mean age 76 years) were included in the analysis. All the SMART cases were successfully completed with no intraoperative or immediate post-operative complications. No cases of mesh-related complications such as infection, immediate stomal prolapse, stenosis, retraction, stomal obstruction, mesh erosion or fistulation were observed. No mesh removal was required. There were two cases of parastomal hernia detected on CT scan. Both cases have remained asymptomatic no intervention was required at this stage. Median follow-up was 24 months. Our medium-term experience has demonstrated the efficacy of SMART in the reduction of parastomal hernia occurrence. With appropriate learning curve, parastomal hernia can be prevented.

Feasibility and outcome after laparoscopic ventral hernia repair using Proceed mesh

DEFF Research Database (Denmark)

Rosenberg, J.; Burcharth, J.

2008-01-01

laparoscopic ventral hernia repair using the Proceed mesh secured with tackers with a double crown technique. Patients were discharged according to standard discharge criteria, and follow-up was performed with a search in the national patient database and with manual search in the patients' files. RESULTS: Our...

An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

International Nuclear Information System (INIS)

Kühnlein, Christian; Smolarkiewicz, Piotr K.

2017-01-01

An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

Energy Technology Data Exchange (ETDEWEB)

Kühnlein, Christian, E-mail: christian.kuehnlein@ecmwf.int; Smolarkiewicz, Piotr K., E-mail: piotr.smolarkiewicz@ecmwf.int

2017-04-01

An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

[Three years results of transvaginal cystocele repair with polypropylene mesh using a tension-free technique].

Science.gov (United States)

El Harrech, Y; Ameur, A; Janane, A; Moufide, K; Ghadouane, M; Abbar, M

2010-01-01

To evaluate the long term efficacy and safety of transvaginal implantation of a non-resorbable synthetic prosthesis (Gynemesh) for the treatment of cystocele using transvaginal free tension technique. Prospective study of patients that have been submitted to correction of cystocele between April 2004 and July 2007. A prolene mesh was cut to an appropriate size to cover the whole cystocele leaving two tabs on each side. The two tabs of the mesh were then placed in paravaginal spaces, tension free, without stitches. Mesh was used in 31 patients. All patients had a symptomatic cystocele >or= 2 according to Baden-Walker halfway classification. Patients were reviewed initially at 1 and 3 month and then every 6 months. The mean age of the patients was 58 years (range: 47-70 years). Mean parity was 5.8 (range 1-11), and mean weight was 75 kg (range 60-82Kg). All women were postmenopausal. The operation was combined with vaginal hysterectomy in 2 patients, Posterior colporraphy in 2 patients, Perineorrhaphy in 1 patient, Sacrospinous fixation in 2 patients, transobturator tape for stress urinary incontinence in 7 women. Average time of surgery was 23 minutes for cystocele. There were no major complications, such as trauma to the bladder, urethra, bowels, or large vessels in the patient group treated. There was no immediate postoperative complications (up to 7 days) recorded. No hematoma or infection was observed in the operative area. Mesh erosion was detected in one patient. It was treated by excision of the eroded part of the mesh. Mean follow-up was 36.4 months (18 to 52 months). Using our definition of success based on both anatomic and functional outcomes, the overall cure rate was 74.19% (asymptomatic with no or grade 1 cystocele). The improvement rate (asymptomatic with a grade 2 cystocele) was 19.35% and the overall failure rate (symptomatic or with a grade 3 or 4 cystocele) was only 6.4% (2 women). The interposition of a sub-vesical transversal tension

Modelling axisymmetric cod-ends made of different mesh types

DEFF Research Database (Denmark)

Priour, D.; Herrmann, Bent; O'Neill, F.G.

2009-01-01

the selectivity process has become more important. This paper presents a model of the deformation of an axisymmetric cod-end. The twine tension and the catch pressure acting on the knots of each mesh along the cod-end profile are calculated, and a Newton-Raphson scheme is used to estimate the equilibrium position...

Stress adapted embroidered meshes with a graded pattern design for abdominal wall hernia repair

Science.gov (United States)

Hahn, J.; Bittrich, L.; Breier, A.; Spickenheuer, A.

2017-10-01

Abdominal wall hernias are one of the most relevant injuries of the digestive system with 25 million patients in 2013. Surgery is recommended primarily using allogenic non-absorbable wrap-knitted meshes. These meshes have in common that their stress-strain behaviour is not adapted to the anisotropic behaviour of native abdominal wall tissue. The ideal mesh should possess an adequate mechanical behaviour and a suitable porosity at the same time. An alternative fabrication method to wrap-knitting is the embroidery technology with a high flexibility in pattern design and adaption of mechanical properties. In this study, a pattern generator was created for pattern designs consisting of a base and a reinforcement pattern. The embroidered mesh structures demonstrated different structural and mechanical characteristics. Additionally, the investigation of the mechanical properties exhibited an anisotropic mechanical behaviour for the embroidered meshes. As a result, the investigated pattern generator and the embroidery technology allow the production of stress adapted mesh structures that are a promising approach for hernia reconstruction.

Mesh complications in female pelvic floor reconstructive surgery and their management: A systematic review

Directory of Open Access Journals (Sweden)

Hemendra N Shah

2012-01-01

Full Text Available We reviewed the incidence, predisposing factors, presentation and management of complications related to the use of synthetic mesh in the management of stress urinary incontinence and pelvic organ prolapse repair. Immediate complications, such as bleeding, hematoma, injury to adjacent organs during placement of mesh and complication of voiding dysfunction are not discussed in this review, since they are primarily related to technique. A PubMed search of related articles published in English was done from April 2008 to March 2011. Key words used were urinary incontinence, mesh, complications, midurethral sling, anterior prolapse, anterior vaginal repair, pelvic organ prolapse, transvaginal mesh, vault prolapse, midurethral slings, female stress urinary incontinence, mesh erosion, vaginal mesh complications, and posterior vaginal wall prolapse. Since there were very few articles dealing with the management of mesh-related complications in the period covered in the search we extended the search from January 2005 onwards. Articles were selected to fit the scope of the topic. In addition, landmark publications and Manufacturer and User Facility Device Experience (MAUDE data (FDA website were included on the present topic. A total of 170 articles were identified. The use of synthetic mesh in sub-urethral sling procedures is now considered the standard for the surgical management of stress urinary incontinence. Synthetic mesh is being increasingly used in the management of pelvic organ prolapse. While the incidence of extrusion and erosion with mid-urethral sling is low, the extrusion rate in prolapse repair is somewhat higher and the use in posterior compartment remains controversial. When used through the abdominal approach the extrusion and erosion rates are lower. The management of mesh complication is an individualized approach. The choice of the technique should be based on the type of mesh complication, location of the extrusion and/or erosion

Mesh complications in female pelvic floor reconstructive surgery and their management: A systematic review

Science.gov (United States)

Shah, Hemendra N.; Badlani, Gopal H.

2012-01-01

We reviewed the incidence, predisposing factors, presentation and management of complications related to the use of synthetic mesh in the management of stress urinary incontinence and pelvic organ prolapse repair. Immediate complications, such as bleeding, hematoma, injury to adjacent organs during placement of mesh and complication of voiding dysfunction are not discussed in this review, since they are primarily related to technique. A PubMed search of related articles published in English was done from April 2008 to March 2011. Key words used were urinary incontinence, mesh, complications, midurethral sling, anterior prolapse, anterior vaginal repair, pelvic organ prolapse, transvaginal mesh, vault prolapse, midurethral slings, female stress urinary incontinence, mesh erosion, vaginal mesh complications, and posterior vaginal wall prolapse. Since there were very few articles dealing with the management of mesh-related complications in the period covered in the search we extended the search from January 2005 onwards. Articles were selected to fit the scope of the topic. In addition, landmark publications and Manufacturer and User Facility Device Experience (MAUDE) data (FDA website) were included on the present topic. A total of 170 articles were identified. The use of synthetic mesh in sub-urethral sling procedures is now considered the standard for the surgical management of stress urinary incontinence. Synthetic mesh is being increasingly used in the management of pelvic organ prolapse. While the incidence of extrusion and erosion with mid-urethral sling is low, the extrusion rate in prolapse repair is somewhat higher and the use in posterior compartment remains controversial. When used through the abdominal approach the extrusion and erosion rates are lower. The management of mesh complication is an individualized approach. The choice of the technique should be based on the type of mesh complication, location of the extrusion and/or erosion, its magnitude

Connectivity editing for quadrilateral meshes

KAUST Repository

Peng, Chihan

2011-12-12

We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.

Connectivity editing for quadrilateral meshes

KAUST Repository

Peng, Chihan; Zhang, Eugene; Kobayashi, Yoshihiro; Wonka, Peter

2011-01-01

We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and impossible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing operations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular vertices (i.e., two). The irregular vertex movement operations are supplemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed highlevel operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadrangulation techniques. © 2011 ACM.

Leveraging the power of mesh

Energy Technology Data Exchange (ETDEWEB)

Glass, H. [Cellnet, Alpharetta, GA (United States)

2006-07-01

Mesh network applications are used by utilities for metering, demand response, and mobile workforce management. This presentation provided an overview of a multi-dimensional mesh application designed to offer improved scalability and higher throughput in advanced metering infrastructure (AMI) systems. Mesh applications can be used in AMI for load balancing and forecasting, as well as for distribution and transmission planning. New revenue opportunities can be realized through the application's ability to improve notification and monitoring services, and customer service communications. Mesh network security features include data encryption, data fragmentation and the automatic re-routing of data. In order to use mesh network applications, networks must have sufficient bandwidth and provide flexibility at the endpoint layer to support multiple devices from multiple vendors, as well as support multiple protocols. It was concluded that smart meters will not enable energy response solutions without an underlying AMI that is reliable, scalable and self-healing. .refs., tabs., figs.

OPTIMASI OLSR ROUTING PROTOCOL PADA JARINGAN WIRELESS MESH DENGAN ADAPTIVE REFRESHING TIME INTERVAL DAN ENHANCE MULTI POINT RELAY SELECTING ALGORITHM

Directory of Open Access Journals (Sweden)

Faosan Mapa

2014-01-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Wireless Mesh Network (WMN adalah suatu konektivitas jaringan yang self-organized, self-configured dan multi-hop. Tujuan dari WMN adalah menawarkan pengguna suatu bentuk jaringan nirkabel yang dapat dengan mudah berkomunikasi dengan jaringan konvensional dengan kecepatan tinggi dan dengan cakupan yang lebih luas serta biaya awal yang minimal. Diperlukan suatu desain protokol routing yang efisien untuk WMN yang secara adaptif dapat mendukung mesh routers dan mesh clients. Dalam tulisan ini, diusulkan untuk mengoptimalkan protokol OLSR, yang merupakan protokol routing proaktif. Digunakan heuristik yang meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki metode MPR selecting algorithm. Suatu analisa dalam meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki algoritma pemilihan MPR menunjukkan kinerja yang signifikan dalam hal throughput jika dibandingkan dengan protokol OLSR yang asli. Akan tetapi, terdapat kenaikan dalam hal delay. Pada simulasi yang dilakukan dapat disimpulkan bahwa OLSR dapat dioptimalkan dengan memodifikasi pemilihan node MPR berdasarkan cost effective dan penyesuaian waktu interval refreshing hello message sesuai dengan keadaan

Porcine dermis compared with polypropylene mesh for laparoscopic sacrocolpopexy: a randomized controlled trial.

Science.gov (United States)

Culligan, Patrick J; Salamon, Charbel; Priestley, Jennifer L; Shariati, Amir

2013-01-01

To compare the surgical outcomes 12 months after laparoscopic sacrocolpopexy performed with porcine dermis and the current gold standard of polypropylene mesh. Patients scheduled for laparoscopic sacrocolpopexy were eligible for this randomized controlled trial. Both our clinical research nurse and the patients were blinded as to which material was used. Our primary end point was objective anatomic cure defined as no pelvic organ prolapse quantification (POP-Q) points Stage 2 or greater at any postoperative interval. Our sample size calculation called for 57 patients in each group to achieve 90% power to detect a 23% difference in objective anatomic cure at 12 months (α=0.05). Our secondary end point was clinical cure. Any patient with a POP-Q point greater than zero, or Point C less than or equal to -5, or any complaints of prolapse symptoms whatsoever on Pelvic Floor Distress Inventory-20 or Pelvic Floor Impact Questionnaire, Short Form 7, or reoperation for prolapse were considered "clinical failures"; the rest were "clinical cures." Statistical comparisons were performed using the χ or independent samples t test as appropriate. As expected, there were no preoperative differences between the porcine (n=57) and mesh (n=58) groups. The 12-month objective anatomic cure rates for the porcine and mesh groups were 80.7% and 86.2%, respectively (P=.24), and the "clinical cure" rates for the porcine and mesh groups were 84.2% and 89.7%, respectively (P=.96). Pelvic Floor Distress Inventory-20 and Pelvic Floor Impact Questionnaire, Short Form 7 score improvements were significant for both groups with no differences found between groups. There were no major operative complications. There were similar outcomes in subjective or objective results 12 months after laparoscopic sacrocolpopexy performed with either porcine dermis or polypropylene mesh. ClinicalTrials.gov, www.clinicaltrials.gov, NCT00564083. I.

Hernia Surgical Mesh Implants

Science.gov (United States)

... knitted mesh or non-knitted sheet forms. The synthetic materials used can be absorbable, non-absorbable or a combination of absorbable and non-absorbable materials. Animal-derived mesh are made of animal tissue, such as intestine or skin, that has been processed and disinfected to be ...

Meshed doped silicon photonic crystals for manipulating near-field thermal radiation

Science.gov (United States)

Elzouka, Mahmoud; Ndao, Sidy

2018-01-01

The ability to control and manipulate heat flow is of great interest to thermal management and thermal logic and memory devices. Particularly, near-field thermal radiation presents a unique opportunity to enhance heat transfer while being able to tailor its characteristics (e.g., spectral selectivity). However, achieving nanometric gaps, necessary for near-field, has been and remains a formidable challenge. Here, we demonstrate significant enhancement of the near-field heat transfer through meshed photonic crystals with separation gaps above 0.5 μm. Using a first-principle method, we investigate the meshed photonic structures numerically via finite-difference time-domain technique (FDTD) along with the Langevin approach. Results for doped-silicon meshed structures show significant enhancement in heat transfer; 26 times over the non-meshed corrugated structures. This is especially important for thermal management and thermal rectification applications. The results also support the premise that thermal radiation at micro scale is a bulk (rather than a surface) phenomenon; the increase in heat transfer between two meshed-corrugated surfaces compared to the flat surface (8.2) wasn't proportional to the increase in the surface area due to the corrugations (9). Results were further validated through good agreements between the resonant modes predicted from the dispersion relation (calculated using a finite-element method), and transmission factors (calculated from FDTD).

Energy optimization based path selection algorithm for IEEE 802.11s wireless mesh networks

CSIR Research Space (South Africa)

Mhlanga, MM

2011-09-01

Full Text Available It is everyone’s dream to have network connectivity anywhere at all times. This dream can only be realized provided there are feasible solutions that are put in place for the next generation of wireless works. Wireless Mesh Networks (WMNs...

[The ultrasound semiotics of uncomplicated wound healing after inguinal mesh plastics].

Science.gov (United States)

Kharitonov, S V; Ziniakova, M V

2012-01-01

Dynamic ultrasound (US) investigation was performed in 89 patients operated on inguinal hernia with the use of meshes of various type. The US scanning proved to be a highly informative means of visualization, allowing the objective postoperative assessment of muscular and aponeurotic structures as well as the implant form and position. The study showed, that the mesh implantation was always accompanied by the exudative tissue reaction, which was determined by the physico-chemical characteristics of the implant.

Long-term results of incisional hernia repair with retromuscular mesh

Directory of Open Access Journals (Sweden)

Miran Rems

2011-04-01

Conclusions: The retromuscular mesh placement for postoperative hernia repair results in a low rate of recurrences and postoperative complications. Complications are more common in patients admitted due to incarceration and in patients having suffered from stoma. Pain inflicted by postoperative hernia repair is an underrated with treatment results.

Laparoscopic sacrocolpopexy for recurrent pelvic organ prolapse after failed transvaginal polypropylene mesh surgery.

Science.gov (United States)

Schmid, Corina; O'Rourke, Peter; Maher, Christopher

2013-05-01

A prospective case series to assess the safety and efficacy of laparoscopic sacrocolpopexy for the surgical management of recurrent pelvic organ prolapse (POP) after transvaginal polypropylene mesh prolapse surgery. Between January and December 2010, women with post-hysterectomy recurrent prolapse (≥ stage 2 POP-Q) after transvaginal polypropylene mesh prolapse surgery were included. Perioperative morbidity and short-term complications were recorded and evaluated. Surgical outcomes were objectively assessed utilising the Pelvic Organ Prolapse Quantification system (POP-Q), the validated, condition-specific Australian Pelvic Floor Questionnaire (APFQ) and the Patient Global Impression of Improvement (PGI-I) at 12 months. All 16 women in this study had undergone surgery with trocar-guided transvaginal polypropylene mesh kits. In 75% the recurrent prolapse affected the compartment of prior mesh surgery with the anterior (81%) and apical (75%) compartment prolapse predominating. At a mean follow-up of 12 months, all women had resolution of awareness of prolapse, had transvaginal mesh surgery is feasible and safe. Further widespread evaluation is required.

Age-stratified analysis of long-term outcomes of transvaginal mesh repair for treatment of pelvic organ prolapse.

Science.gov (United States)

Dong, Shengnan; Zhong, Yanbo; Chu, Lei; Li, Huaifang; Tong, Xiaowen; Wang, Jianjun

2016-10-01

To investigate long-term outcomes after transvaginal mesh repair among patients with pelvic organ prolapse in different age groups. A retrospective cohort study was conducted among women who underwent transvaginal mesh repair with polypropylene mesh for pelvic organ prolapse of stage II or higher between January 2007 and November 2011 at a center in Shanghai, China. Patients were invited to attend a follow-up appointment between July 2014 and May 2015. Surgical outcomes were compared among three age groups (≤59, 60-74, and ≥75 years), and quality-of-life questionnaires were evaluated. Multivariate logistic regression was used to identify risk factors associated with recurrent prolapse and mesh exposure. Among 158 patients, 143 (90.5%) were objectively cured and 149 (94.3%) were subjectively cured at follow-up. Surgical outcomes were similar across all age groups. Significant improvements were observed on the Pelvic Floor Distress Inventory across all applicable subscales in all age groups (Pmesh exposure (odds ratio 11.89, 95% confidence interval 1.08-131.48; P=0.043). Transvaginal mesh repair was found to be a safe and effective technique for treating pelvic organ prolapse among women of all ages. An active postoperative sex life increased the odds of mesh exposure. Copyright © 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Repair of large frontal temporal parietal skull defect with digitally reconstructed titanium mesh: a report of 20 cases

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Gang-ge CHENG

2013-09-01

Full Text Available Objective　To explore the clinical effect and surgical technique of the repair of large defect involving frontal, temporal, and parietal regions using digitally reconstructed titanium mesh. Methods　Twenty patients with large frontal, temporal, and parietal skull defect hospitalized in Air Force General Hospital from November 2006 to May 2012 were involved in this study. In these 20 patients, there were 13 males and 7 females, aged 18-58 years (mean 39 years, and the defect size measured from 7.0cm×9.0cm to 11.5cm×14.0cm (mean 8.5cm×12.0cm. Spiral CT head scan and digital three-dimensional reconstruction of skull were performed in all the patients. The shape and geometric size of skull defect was traced based on the symmetry principle, and then the data were transferred into digital precision lathe to reconstruct a titanium mesh slightly larger (1.0-1.5cm than the skull defect, and the finally the prosthesis was perfected after pruning the border. Cranioplasty was performed 6-12 months after craniotomy using the digitally reconstructed titanium mesh. Results　The digitally reconstructed titanium mesh was used in 20 patients with large frontal, temporal, parietal skull defect. The surgical technique was relatively simple, and the surgical duration was shorter than before. The titanium mesh fit to the defect of skull accurately with satisfactory molding effect, good appearance and symmetrical in shape. No related complication was found in all the patients. Conclusion　Repair of large frontal, temporal, parietal skull defect with digitally reconstructed titanium mesh is more advantageous than traditional manual reconstruction, and it can improve the life quality of patients.

Atlas-Based Automatic Generation of Subject-Specific Finite Element Tongue Meshes.

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Bijar, Ahmad; Rohan, Pierre-Yves; Perrier, Pascal; Payan, Yohan

2016-01-01

Generation of subject-specific 3D finite element (FE) models requires the processing of numerous medical images in order to precisely extract geometrical information about subject-specific anatomy. This processing remains extremely challenging. To overcome this difficulty, we present an automatic atlas-based method that generates subject-specific FE meshes via a 3D registration guided by Magnetic Resonance images. The method extracts a 3D transformation by registering the atlas' volume image to the subject's one, and establishes a one-to-one correspondence between the two volumes. The 3D transformation field deforms the atlas' mesh to generate the subject-specific FE mesh. To preserve the quality of the subject-specific mesh, a diffeomorphic non-rigid registration based on B-spline free-form deformations is used, which guarantees a non-folding and one-to-one transformation. Two evaluations of the method are provided. First, a publicly available CT-database is used to assess the capability to accurately capture the complexity of each subject-specific Lung's geometry. Second, FE tongue meshes are generated for two healthy volunteers and two patients suffering from tongue cancer using MR images. It is shown that the method generates an appropriate representation of the subject-specific geometry while preserving the quality of the FE meshes for subsequent FE analysis. To demonstrate the importance of our method in a clinical context, a subject-specific mesh is used to simulate tongue's biomechanical response to the activation of an important tongue muscle, before and after cancer surgery.

A comparative study of onlay and retrorectus mesh placement in incisional hernia repair

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Kundan Kharde

2013-01-01

Full Text Available Introduction: Incisional hernia after abdominal surgery is a well-known complication and the incidence of incisional hernias continues to be 2-11% after laparotomy. The repair of incisional hernia has always been a challenge to the surgeon. Various operative techniques for the repair of incisional hernia are in practice; however, the management is not standardized. The retro-rectus mesh placement or the sub-lay technique, popularized by Rives and Stoppa in Europe, has been reported to be quite effective, with low recurrence rates (0-23% and minimal complications. Aims and Objective: The purpose of this study was to compare the traditional on-lay mesh and retro-rectus mesh placement in incisional hernia repairs in terms of time taken for surgery, early complications (wound infections, Mesh extrusion, and Delayed complications (Recurrence. Materials and Methods: This is a prospective study which was conducted in the surgical department of our hospital. A total of 50 cases were included in this study. Of these cases, 25 cases were operated by the on-lay mesh method and 25 by retro-rectus mesh placement. Only the patients with midline hernias up to 10 cm in diameter were included in the study. Result: The operative time for retro-rectus mesh placement was insignificantly higher than that of on-lay mesh repair, whereas, complications like superficial Surgical site infection SSI were identical in both the study groups, but deep SSI leading to infection of mesh was higher in on-lay mesh repair. The recurrence rate was found to be 4% in on-lay mesh repair and 0% in retro-rectus mesh repair. Conclusion: The follow-up period in this study was 6months; hence, late recurrences were not taken into account. However, the low rate of local complications and the low recurrence rate indicate that retro-rectus mesh repair has an advantage over traditional on-lay repair.

The Role of Vaginal Mesh Procedures in Pelvic Organ Prolapse Surgery in View of Complication Risk

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David R. Ellington

2013-01-01

Full Text Available Synthetic transvaginal mesh has been employed in the treatment of pelvic organ prolapse for more than a decade. As the use of these devices increased during this period so did adverse event reporting. In 2008, the Food and Drug Administration (FDA Public Health Notification informed physicians and patients of rising concerns with the use of synthetic transvaginal mesh. Shortly thereafter and in parallel to marked increases in adverse event reporting within the Manufacturer and User Device Experience (MAUDE, the FDA released a Safety Communication regarding urogynecologic surgical mesh use. Following this report and in the wake of increased medical industry product withdrawal, growing medicolegal concerns, patient safety, and clinical practice controversy, many gynecologists and pelvic reconstructive surgeons are left with limited long-term data, clinical guidance, and growing uncertainty regarding the role of synthetic transvaginal mesh use in pelvic organ prolapse. This paper reviews the reported complications of synthetic transvaginal mesh with an evidence-based approach as well as providing suggested guidance for the future role of its use amidst the controversy.

The Role of Vaginal Mesh Procedures in Pelvic Organ Prolapse Surgery in View of Complication Risk

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Ellington, David R.; Richter, Holly E.

2013-01-01

Synthetic transvaginal mesh has been employed in the treatment of pelvic organ prolapse for more than a decade. As the use of these devices increased during this period so did adverse event reporting. In 2008, the Food and Drug Administration (FDA) Public Health Notification informed physicians and patients of rising concerns with the use of synthetic transvaginal mesh. Shortly thereafter and in parallel to marked increases in adverse event reporting within the Manufacturer and User Device Experience (MAUDE), the FDA released a Safety Communication regarding urogynecologic surgical mesh use. Following this report and in the wake of increased medical industry product withdrawal, growing medicolegal concerns, patient safety, and clinical practice controversy, many gynecologists and pelvic reconstructive surgeons are left with limited long-term data, clinical guidance, and growing uncertainty regarding the role of synthetic transvaginal mesh use in pelvic organ prolapse. This paper reviews the reported complications of synthetic transvaginal mesh with an evidence-based approach as well as providing suggested guidance for the future role of its use amidst the controversy. PMID:24069035

Fog water collection effectiveness: Mesh intercomparisons

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Fernandez, Daniel; Torregrosa, Alicia; Weiss-Penzias, Peter; Zhang, Bong June; Sorensen, Deckard; Cohen, Robert; McKinley, Gareth; Kleingartner, Justin; Oliphant, Andrew; Bowman, Matthew

2018-01-01

To explore fog water harvesting potential in California, we conducted long-term measurements involving three types of mesh using standard fog collectors (SFC). Volumetric fog water measurements from SFCs and wind data were collected and recorded in 15-minute intervals over three summertime fog seasons (2014–2016) at four California sites. SFCs were deployed with: standard 1.00 m2 double-layer 35% shade coefficient Raschel; stainless steel mesh coated with the MIT-14 hydrophobic formulation; and FogHa-Tin, a German manufactured, 3-dimensional spacer fabric deployed in two orientations. Analysis of 3419 volumetric samples from all sites showed strong relationships between mesh efficiency and wind speed. Raschel mesh collected 160% more fog water than FogHa-Tin at wind speeds less than 1 m s–1 and 45% less for wind speeds greater than 5 m s–1. MIT-14 coated stainless-steel mesh collected more fog water than Raschel mesh at all wind speeds. At low wind speeds of wind speeds of 4–5 m s–1, it collected 41% more. FogHa-Tin collected 5% more fog water when the warp of the weave was oriented vertically, per manufacturer specification, than when the warp of the weave was oriented horizontally. Time series measurements of three distinct mesh across similar wind regimes revealed inconsistent lags in fog water collection and inconsistent performance. Since such differences occurred under similar wind-speed regimes, we conclude that other factors play important roles in mesh performance, including in-situ fog event and aerosol dynamics that affect droplet-size spectra and droplet-to-mesh surface interactions.

Technique and complications of reconstruction of the pelvic floor with polyglactin mesh

International Nuclear Information System (INIS)

Sener, S.F.; Imperato, J.P.; Blum, M.D.; Ignatoff, J.M.; Soper, T.G.; Winchester, D.P.; Meiselman, M.

1989-01-01

A polyglactin mesh sling was used to reconstruct the pelvis in eight patients after colorectal or urologic resections in preparation for postoperative radiation therapy. There were three perioperative complications--a pelvic abscess requiring percutaneous drainage, a wound dehiscence and a herniation of the small intestine between the pelvic sidewall and mesh requiring small intestinal resection. There were two delayed complications, both partial small intestinal obstructions. One occurred just after the conclusion of radiation treatment and the other occurred five months after the conclusion of radiation therapy. Both obstructions responded to conservative management. None of the common acute radiation effects occurred during radiotherapy. One patient with delayed partial small intestinal obstruction had possible late radiation effects. The median follow-up period after radiation therapy was 12.5 months. Despite the complications described in this report, the use of a polyglactin mesh sling as an adjunct to resection of carcinoma of the pelvis has merit and should be studied further

3D-2D Deformable Image Registration Using Feature-Based Nonuniform Meshes.

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Zhong, Zichun; Guo, Xiaohu; Cai, Yiqi; Yang, Yin; Wang, Jing; Jia, Xun; Mao, Weihua

2016-01-01

By using prior information of planning CT images and feature-based nonuniform meshes, this paper demonstrates that volumetric images can be efficiently registered with a very small portion of 2D projection images of a Cone-Beam Computed Tomography (CBCT) scan. After a density field is computed based on the extracted feature edges from planning CT images, nonuniform tetrahedral meshes will be automatically generated to better characterize the image features according to the density field; that is, finer meshes are generated for features. The displacement vector fields (DVFs) are specified at the mesh vertices to drive the deformation of original CT images. Digitally reconstructed radiographs (DRRs) of the deformed anatomy are generated and compared with corresponding 2D projections. DVFs are optimized to minimize the objective function including differences between DRRs and projections and the regularity. To further accelerate the above 3D-2D registration, a procedure to obtain good initial deformations by deforming the volume surface to match 2D body boundary on projections has been developed. This complete method is evaluated quantitatively by using several digital phantoms and data from head and neck cancer patients. The feature-based nonuniform meshing method leads to better results than either uniform orthogonal grid or uniform tetrahedral meshes.

3D-2D Deformable Image Registration Using Feature-Based Nonuniform Meshes

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Zichun Zhong

2016-01-01

Full Text Available By using prior information of planning CT images and feature-based nonuniform meshes, this paper demonstrates that volumetric images can be efficiently registered with a very small portion of 2D projection images of a Cone-Beam Computed Tomography (CBCT scan. After a density field is computed based on the extracted feature edges from planning CT images, nonuniform tetrahedral meshes will be automatically generated to better characterize the image features according to the density field; that is, finer meshes are generated for features. The displacement vector fields (DVFs are specified at the mesh vertices to drive the deformation of original CT images. Digitally reconstructed radiographs (DRRs of the deformed anatomy are generated and compared with corresponding 2D projections. DVFs are optimized to minimize the objective function including differences between DRRs and projections and the regularity. To further accelerate the above 3D-2D registration, a procedure to obtain good initial deformations by deforming the volume surface to match 2D body boundary on projections has been developed. This complete method is evaluated quantitatively by using several digital phantoms and data from head and neck cancer patients. The feature-based nonuniform meshing method leads to better results than either uniform orthogonal grid or uniform tetrahedral meshes.

Comparison of a lightweight polypropylene mesh (Optilene® LP) and a large-pore knitted PTFE mesh (GORE® INFINIT® mesh)--Biocompatibility in a standardized endoscopic extraperitoneal hernia model.

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Jacob, Dietmar A; Schug-Pass, Christine; Sommerer, Florian; Tannapfel, Andrea; Lippert, Hans; Köckerling, Ferdinand

2012-02-01

The use of a mesh with good biocompatibility properties is of decisive importance for the avoidance of recurrences and chronic pain in endoscopic hernia repair surgery. As we know from numerous experiments and clinical experience, large-pore, lightweight polypropylene meshes possess the best biocompatibility. However, large-pore meshes of different polymers may be used as well and might be an alternative solution. Utilizing a totally extraperitoneal technique in an established animal model, 20 domestic pigs were implanted with either a lightweight large-pore polypropylene (PP) mesh (Optilene® LP) or a medium-weight large-pore knitted polytetrafluorethylene (PTFE) mesh (GORE® INFINIT® mesh). After 94 days, the pigs were sacrificed and postmortem diagnostic laparoscopy was performed, followed by explantation of the specimens for macroscopic, histological and immunohistochemical evaluation. The mean mesh shrinkage rate was 14.2% for Optilene® LP vs. 24.7% for INFINIT® mesh (p = 0.017). The partial volume of the inflammatory cells was 11.2% for Optilene® LP vs. 13.9% for INFINIT (n.s.). CD68 was significantly higher for INFINIT (11.8% vs. 5.6%, p = 0.007). The markers of cell turnover, namely Ki67 and the apoptotic index, were comparable at 6.4% vs. 12.4% (n.s.) and 1.6% vs. 2.0% (n.s.). In the extracellular matrix, TGF-β was 35.4% for Optilene® LP and 31.0% for INFINIT® (n.s.). Collagen I (pos/300 μm) deposits were 117.8 and 114.9, respectively. In our experimental examinations, Optilene® LP and INFINIT® showed a comparable biocompatibility in terms of chronic inflammatory reaction; however, the shrinkage rate was significantly higher for INFINIT® after 3 months. The higher shrinkage rate of INFINIT® should be taken into account when choosing the mesh size for an adequate hernia overlap.

Mesh fixation in laparoscopic incisional hernia repair: glue fixation provides attachment strength similar to absorbable tacks but differs substantially in different meshes.

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Rieder, Erwin; Stoiber, Martin; Scheikl, Verena; Poglitsch, Marcus; Dal Borgo, Andrea; Prager, Gerhard; Schima, Heinrich

2011-01-01

Laparoscopic ventral hernia repair has gained popularity among minimally invasive surgeons. However, mesh fixation remains a matter of discussion. This study was designed to compare noninvasive fibrin-glue attachment with tack fixation of meshes developed primarily for intra-abdominal use. It was hypothesized that particular mesh structures would substantially influence detachment force. For initial evaluation, specimens of laminated polypropylene/polydioxanone meshes were anchored to porcine abdominal walls by either helical titanium tacks or absorbable tacks in vitro. A universal tensile-testing machine was used to measure tangential detachment forces (TF). For subsequent experiments of glue fixation, polypropylene/polydioxanone mesh and 4 additional meshes with diverse particular mesh structure, ie, polyvinylidene fluoride/polypropylene mesh, a titanium-coated polypropylene mesh, a polyester mesh bonded with a resorbable collagen, and a macroporous condensed PTFE mesh were evaluated. TF tests revealed that fibrin-glue attachment was not substantially different from that achieved with absorbable tacks (median TF 7.8 Newton [N], range 1.3 to 15.8 N), but only when certain open porous meshes (polyvinylidene fluoride/polypropylene mesh: median 6.2 N, range 3.4 to 10.3 N; titanium-coated polypropylene mesh: median 5.2 N, range 2.1 to 11.7 N) were used. Meshes coated by an anti-adhesive barrier (polypropylene/polydioxanone mesh: median 3.1 N, range 1.7 to 5.8 N; polyester mesh bonded with a resorbable collagen: median 1.3 N, range 0.5 to 1.9 N), or the condensed PTFE mesh (median 3.1 N, range 2.1 to 7.0 N) provided a significantly lower TF (p < 0.01). Fibrin glue appears to be an appealing noninvasive option for mesh fixation in laparoscopic ventral hernia repair, but only if appropriate meshes are used. Glue can also serve as an adjunct to mechanical fixation to reduce the number of invasive tacks. Copyright © 2010 American College of Surgeons. Published by Elsevier

Quality of pharmacy-specific Medical Subject Headings (MeSH) assignment in pharmacy journals indexed in MEDLINE.

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Minguet, Fernando; Salgado, Teresa M; van den Boogerd, Lucienne; Fernandez-Llimos, Fernando

2015-01-01

The Medical Subject Headings (MeSH) is the National Library of Medicine (NLM) controlled vocabulary for indexing articles. Inaccuracies in the MeSH thesaurus have been reported for several areas including pharmacy. To assess the quality of pharmacy-specific MeSH assignment to articles indexed in pharmacy journals. The 10 journals containing the highest number of articles published in 2012 indexed under the MeSH 'Pharmacists' were identified. All articles published over a 5-year period (2008-2012) in the 10 previously selected journals were retrieved from PubMed. MeSH terms used to index these articles were extracted and pharmacy-specific MeSH terms were identified. The frequency of use of pharmacy-specific MeSH terms was calculated across journals. A total of 6989 articles were retrieved from the 10 pharmacy journals, of which 328 (4.7%) were articles not fully indexed and therefore did not contain any MeSH terms assigned. Among the 6661 articles fully indexed, the mean number of MeSH terms was 10.1 (SD = 4.0), being 1.0 (SD = 1.3) considered as Major MeSH. Both values significantly varied across journals. The mean number of pharmacy-specific MeSH terms per article was 0.9 (SD = 1.2). A total of 3490 (52.4%) of the 6661 articles were indexed in pharmacy journals without a single pharmacy-specific MeSH. Of the total 67193 MeSH terms assigned to articles, on average 10.5% (SD = 13.9) were pharmacy-specific MeSH. A statistically significant different pattern of pharmacy-specific MeSH assignment was identified across journals (Kruskal-Wallis P journals can be improved to further enhance evidence gathering in pharmacy. Over half of the articles published in the top-10 journals publishing pharmacy literature were indexed without a single pharmacy-specific MeSH. Copyright © 2015 Elsevier Inc. All rights reserved.

Parallel adaptive simulations on unstructured meshes

International Nuclear Information System (INIS)

Shephard, M S; Jansen, K E; Sahni, O; Diachin, L A

2007-01-01

This paper discusses methods being developed by the ITAPS center to support the execution of parallel adaptive simulations on unstructured meshes. The paper first outlines the ITAPS approach to the development of interoperable mesh, geometry and field services to support the needs of SciDAC application in these areas. The paper then demonstrates the ability of unstructured adaptive meshing methods built on such interoperable services to effectively solve important physics problems. Attention is then focused on ITAPs' developing ability to solve adaptive unstructured mesh problems on massively parallel computers

[Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

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Han, Xiao-hui; Zhang, Jia-yu; Cai, Jian-qiu; Shi, Ming-guang

2011-05-10

To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

Prevention of a parastomal hernia by biological mesh reinforcement

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René H Fortelny

2015-10-01

Full Text Available Introduction: In the field of hernia prevention the prophylactic mesh-reinforcement of stoma-sites is one of the most controversially discussed issues. The incidence of parastomal hernias in the literature reported to be up to 48.1% after end colostomy and up to 30.8 % after of loop colostomy respectively, but still remains uncertain due to diagnostic variety of clinical or radiological methods, heterogeneous patient groups and variable follow-up intervals respectively. Anyway, the published data regarding the use of synthetic or bio-prostethic meshes in the prevention of parastomal hernia at the primary operation are very scarce. Methods: A literature search of the Medline database in terms of biological prophylactic mesh implantation in stoma creation identified 6 systematic reviews, 2 randomized controlled trials (RCT, 2 case controlled studies and 1 technical report. Results: In a systematic review focusing on the prevention of parastomal hernia including only RCTs encompassing one RCT using bio-prosthetic mesh the incidence of herniation was 12.5 % compared to 53% in the control group (p<0.0001. In 1 RCT and 2 case control studies respectively, there was a significant smaller incidence of parastomal herniation as well as a similar complication rate compared to the control group respectively. Only in 1 RCT no significant difference regarding the incidence of parastomal hernia was reported with comparable complication rates. Conclusion: Thus so far 2 RCT and 2 case control studies are published with prophylactic bio prosthetic reinforcement in stoma sites. The majority revealed significant better results in terms of parastomal herniation and without any mesh related complications in comparison to the non mesh group. Further multicenter RCT are required to achieve a sufficient level of recommendation.

Automatic mesh generation with QMESH program

International Nuclear Information System (INIS)

Ise, Takeharu; Tsutsui, Tsuneo

1977-05-01

Usage of the two-dimensional self-organizing mesh generation program, QMESH, is presented together with the descriptions and the experience, as it has recently been converted and reconstructed from the NEACPL version to the FACOM. The program package consists of the QMESH code to generate quadrilaterial meshes with smoothing techniques, the QPLOT code to plot the data obtained from the QMESH on the graphic COM, and the RENUM code to renumber the meshes by using a bandwidth minimization procedure. The technique of mesh reconstructuring coupled with smoothing techniques is especially useful when one generates the meshes for computer codes based on the finite element method. Several typical examples are given for easy access to the QMESH program, which is registered in the R.B-disks of JAERI for users. (auth.)

In-vitro examination of the biocompatibility of fibroblast cell lines on alloplastic meshes and sterilized polyester mosquito mesh.

Science.gov (United States)

Wiessner, R; Kleber, T; Ekwelle, N; Ludwig, K; Richter, D-U

2017-06-01

The use of alloplastic implants for tissue strengthening when treating hernias is an established therapy worldwide. Despite the high incidence of hernias in Africa and Asia, the implantation of costly mesh netting is not financially feasible. Because of that various investigative groups have examined the use of sterilized mosquito netting. The animal experiments as well as the clinical trials have both shown equivalent short- and long-term results. The goal of this paper is the comparison of biocompatibility of human fibroblasts on the established commercially available nets and on sterilized polyester mosquito mesh over a period of 12 weeks. Three commercially available plastic mesh types and a gas-sterilized mosquito polyethylenterephtalate (polyester) mesh were examined. Human fibroblasts from subcutaneous healthy tissue were used. Various tests for evaluating the growth behavior and the cell morphology of human fibroblasts were conducted. The semi-quantitative (light microscopy) and qualitative (scanning electron microscopy) analyses were performed after 1 week and then again after 12 weeks. The cell proliferation and cytotoxicity of the implants were investigated with the help of the 5'-bromo-2'-deoxyuridine (BrdU)-cell proliferation test and the LDH-cytotoxicity test. The number of live cells per ml was determined with the Bürker counting chamber. In addition, analyses were made of the cell metabolism (oxidative stress) by measuring the pH value, hydrogen peroxide, and glycolysis. After 12 weeks, a proliferation of fibroblasts on all mesh is documented. No mesh showed a complete apoptosis of the cells. This qualitative observation could be confirmed quantitatively in a biochemical assay by marking the proliferating cells with BrdU. The biochemical analysis brought the proof that the materials used, including the polyester of the mosquito mesh, are not cytotoxic for the fibroblasts. The vitality of the cells was between 94 and 98%. The glucose metabolism

Facial reconstruction using polypropylene mesh after resection of maxillary ossifying fibroma

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R. Soesanto

2012-09-01

Full Text Available Background: Ossifying fibroma is a variant of fibrous dysplasia and catagorized as osteofibrosis lesion. It commonly affects long bones but occasionally involves jaws. Mandible affected more common than maxilla. The treatment of ossifying fibroma include excision and resection. Excision of lesion and resection of maxilla could cause facial defect which cannot be reconstructed with bone graft. Purpose: The aim of this case report is to report the potential use of polypropylene mesh in facial reconstruction after hemimaxillectomy in patients diagnosed with ossifying fibroma of the maxilla. Case: A 17-years-old female patient came to Oral and Maxillofacial Surgery clinic, Dental Hospital, Faculty of Dentistry, Airlangga University, with chief complaint of swelling in the upper left cheek of 2 years duration which was not related to any history of toothache. Patient also complained of the itchiness and pain on the swelling area occasionally as well as salty discharge from the mass. The FNA was done and the citology result indicated a benign mesenchimal tumor. Incisonal biopsy was subsequently performed and the histopathology report confirmed the diagnosis of cementifying fibroma. Case management: Left hemimaxillectomy was done, and post surgical defect in the facial and buccal aspect was immediately reconstructed using three layers of polypropylene mesh. On follow-up, eleven months post-operatively, the patient was well and there was no facial deformity or asymmetry. Conclusion: Polypropylene mesh is a potential material for facial reconstruction as it can reduce the risk of facial deformity after hemimaxillectomy of patients with tumor of the maxilla.Latar belakang: Ossifying fibroma merupakan varian dari fibrous dysplasia dan termasuk di dalam kategori lesi osteofibrosis. Umumnya mengenai tulang panjang tetapi dapat juga mengenai rahang dan lebih banyak menyerang tulang mandibula dibanding maksila. Perawatan ossifying fibroma dilakukan dengan

Long-term anisotropic mechanical response of surgical meshes used to repair abdominal wall defects.

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Hernández-Gascón, B; Peña, E; Pascual, G; Rodríguez, M; Bellón, J M; Calvo, B

2012-01-01

Routine hernia repair surgery involves the implant of synthetic mesh. However, this type of procedure may give rise to pain and bowel incarceration and strangulation, causing considerable patient disability. The purpose of this study was to compare the long-term behaviour of three commercial meshes used to repair the partially herniated abdomen in New Zealand White rabbits: the heavyweight (HW) mesh, Surgipro(®) and lightweight (LW) mesh, Optilene(®), both made of polypropylene (PP), and a mediumweight (MW) mesh, Infinit(®), made of polytetrafluoroethylene (PTFE). The implanted meshes were mechanical and histological assessed at 14, 90 and 180 days post-implant. This behaviour was compared to the anisotropic mechanical behaviour of the unrepaired abdominal wall in control non-operated rabbits. Both uniaxial mechanical tests conducted in craneo-caudal and perpendicular directions and histological findings revealed substantial collagen growth over the repaired hernial defects causing stiffness in the repair zone, and thus a change in the original properties of the meshes. The mechanical behaviour of the healthy tissue in the craneo-caudal direction was not reproduced by any of the implanted meshes after 14 days or 90 days of implant, whereas in the perpendicular direction, SUR and OPT achieved similar behaviour. From a mechanical standpoint, the anisotropic PP-lightweight meshes may be considered a good choice in the long run, which correlates with the structure of the regenerated tissue. Copyright © 2011 Elsevier Ltd. All rights reserved.

Refficientlib: an efficient load-rebalanced adaptive mesh refinement algorithm for high-performance computational physics meshes

OpenAIRE

Baiges Aznar, Joan; Bayona Roa, Camilo Andrés

2017-01-01

No separate or additional fees are collected for access to or distribution of the work. In this paper we present a novel algorithm for adaptive mesh refinement in computational physics meshes in a distributed memory parallel setting. The proposed method is developed for nodally based parallel domain partitions where the nodes of the mesh belong to a single processor, whereas the elements can belong to multiple processors. Some of the main features of the algorithm presented in this paper a...

[Vaginal mesh operations in the urogynecological practice after the FDA warnings. Use or not to use mesh?

Science.gov (United States)

Fekete, Zoltán; Körösi, Szilvia; Németh, Gábor

2018-03-01

The prevalence of pelvic organ prolapse (POP) with aging is escalating alarmingly, and now becoming a growing epidemic among the elderly. Synthetic transvaginal mesh (TVM) has been employed with increasing popularity in the treatment of POP until the end of the last decade. After the U.S. Drug and Food Administration (FDA) warnings in the years 2008 and 2011, the number of vaginal mesh operations has decreased dramatically. The aim of the study was to evaluate and compare the anti-POP effectivity, the anti-stress incontinence (anti-SUI) efficacy, and the late (36 months) post-operative complications of the anterior vaginoplasty and the TVM operations. We analysed the clinical data from 120 patients with stage II-III anterior prolapse and concomitant SUI who had undergone surgery at a tertiary referral centre in Hungary between January 2013 and January 2014. Sixty patients underwent Kelly-Stoeckel vaginoplasty and the other 60 cases had TVM operation. The surgical complications were classified using the Clavien-Dindo (CD) classification system. The anti-POP (91.6% vs. 63.3%; pmesh surgery represents an effective procedure for prolapse and concomitant SUI with a decreased risk of short- and long-term complications. Orv Hetil. 2018; 159(10): 397-404.

Outcomes of Orbital Floor Reconstruction After Extensive Maxillectomy Using the Computer-Assisted Fabricated Individual Titanium Mesh Technique.

Science.gov (United States)

Zhang, Wen-Bo; Mao, Chi; Liu, Xiao-Jing; Guo, Chuan-Bin; Yu, Guang-Yan; Peng, Xin

2015-10-01

Orbital floor defects after extensive maxillectomy can cause severe esthetic and functional deformities. Orbital floor reconstruction using the computer-assisted fabricated individual titanium mesh technique is a promising method. This study evaluated the application and clinical outcomes of this technique. This retrospective study included 10 patients with orbital floor defects after maxillectomy performed from 2012 through 2014. A 3-dimensional individual stereo model based on mirror images of the unaffected orbit was obtained to fabricate an anatomically adapted titanium mesh using computer-assisted design and manufacturing. The titanium mesh was inserted into the defect using computer navigation. The postoperative globe projection and orbital volume were measured and the incidence of postoperative complications was evaluated. The average postoperative globe projection was 15.91 ± 1.80 mm on the affected side and 16.24 ± 2.24 mm on the unaffected side (P = .505), and the average postoperative orbital volume was 26.01 ± 1.28 and 25.57 ± 1.89 mL, respectively (P = .312). The mean mesh depth was 25.11 ± 2.13 mm. The mean follow-up period was 23.4 ± 7.7 months (12 to 34 months). Of the 10 patients, 9 did not develop diplopia or a decrease in visual acuity and ocular motility. Titanium mesh exposure was not observed in any patient. All patients were satisfied with their postoperative facial symmetry. Orbital floor reconstruction after extensive maxillectomy with an individual titanium mesh fabricated using computer-assisted techniques can preserve globe projection and orbital volume, resulting in successful clinical outcomes. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Full-thickness skin graft vs. synthetic mesh in the repair of giant incisional hernia: a randomized controlled multicenter study.

Science.gov (United States)

Clay, L; Stark, B; Gunnarsson, U; Strigård, K

2018-04-01

Repair of large incisional hernias includes the implantation of a synthetic mesh, but this may lead to pain, stiffness, infection and enterocutaneous fistulae. Autologous full-thickness skin graft as on-lay reinforcement has been tested in eight high-risk patients in a proof-of-concept study, with satisfactory results. In this multicenter randomized study, the use of skin graft was compared to synthetic mesh in giant ventral hernia repair. Non-smoking patients with a ventral hernia > 10 cm wide were randomized to repair using an on-lay autologous full-thickness skin graft or a synthetic mesh. The primary endpoint was surgical site complications during the first 3 months. A secondary endpoint was patient comfort. Fifty-three patients were included. Clinical evaluation was performed at a 3-month follow-up appointment. There were fewer patients in the skin graft group reporting discomfort: 3 (13%) vs. 12 (43%) (p = 0.016). Skin graft patients had less pain and a better general improvement. No difference was seen regarding seroma; 13 (54%) vs. 13 (46%), or subcutaneous wound infection; 5 (20%) vs. 7 (25%). One recurrence appeared in each group. Three patients in the skin graft group and two in the synthetic mesh group were admitted to the intensive care unit. No difference was seen for the primary endpoint short-term surgical complication. Full-thickness skin graft appears to be a reliable material for ventral hernia repair producing no more complications than when using synthetic mesh. Patients repaired with a skin graft have less subjective abdominal wall symptoms.

Unstructured mesh adaptivity for urban flooding modelling

Science.gov (United States)

Hu, R.; Fang, F.; Salinas, P.; Pain, C. C.

2018-05-01

Over the past few decades, urban floods have been gaining more attention due to their increase in frequency. To provide reliable flooding predictions in urban areas, various numerical models have been developed to perform high-resolution flood simulations. However, the use of high-resolution meshes across the whole computational domain causes a high computational burden. In this paper, a 2D control-volume and finite-element flood model using adaptive unstructured mesh technology has been developed. This adaptive unstructured mesh technique enables meshes to be adapted optimally in time and space in response to the evolving flow features, thus providing sufficient mesh resolution where and when it is required. It has the advantage of capturing the details of local flows and wetting and drying front while reducing the computational cost. Complex topographic features are represented accurately during the flooding process. For example, the high-resolution meshes around the buildings and steep regions are placed when the flooding water reaches these regions. In this work a flooding event that happened in 2002 in Glasgow, Scotland, United Kingdom has been simulated to demonstrate the capability of the adaptive unstructured mesh flooding model. The simulations have been performed using both fixed and adaptive unstructured meshes, and then results have been compared with those published 2D and 3D results. The presented method shows that the 2D adaptive mesh model provides accurate results while having a low computational cost.

Removal of Polypropylene Sling Mesh From the Urethra: An Anatomic Technique.

Science.gov (United States)

Freilich, Drew A; Rovner, Eric S

2015-07-01

To describe a technique for removal of intraurethral mesh with minimal disruption of the periurethral anatomy. Through a midline transvaginal approach the sling is located lateral to the urethra and divided. The medial portion of the divided sling is carefully dissected back to its entrance laterally into the urethral lumen. A stay suture is placed on the dissected sling. The sling is located on the contralateral side and likewise divided and dissected back to the urethral lumen. The completely dissected sling is pulled through such that the holding stitch is through and through the urethral lumen, allowing easy localization of the urethral defect on lateral walls of the urethra. These defects are closed with an absorbable suture and the vaginal incision is closed. Three patients have undergone a transvaginal removal of their intraurethral mesh using the described technique. At a mean follow-up of 6.0 months, there were no intraoperative or postoperative complications. All patients were obstructed preoperatively and all developed stress urinary incontinence postoperatively requiring 0-1 pads per day. Current approaches to the surgical repair of chronic intraurethral mesh have significant limitations that are minimized by the described technique. This anatomic removal of mesh from the urethra has several advantages including no disruption of the ventral wall of the urethra, complete removal of foreign body from the urethra, and simplified localization of the urethral wall defect to allow for anatomic closure. Copyright © 2015 Elsevier Inc. All rights reserved.

Retrospective analysis of a VACM (vacuum-assisted closure and mesh-mediated fascial traction treatment manual for temporary abdominal wall closure – results of 58 consecutive patients

Directory of Open Access Journals (Sweden)

Beltzer, Christian

2016-07-01

Full Text Available Introduction: The optimal treatment concept for temporary abdominal closure (TAC in critically ill visceral surgery patients with open abdomen (OA continues to be unclear. The VACM (vacuum-assisted closure and mesh-mediated fascial traction therapy seems to permit higher delayed primary fascial closure rates (FCR than other TAC procedures. Material and methods: Patients of our clinic (n=58 who were treated by application of a VAC/VACM treatment manual in the period from 2005 to 2008 were retrospectively analysed. Results: The overall FCR of all patients was 48.3% (95% confidence interval: 34.95–61.78. An FCR of 61.3% was achieved in patients who had a vicryl mesh implanted at the fascial level (VACM therapy in the course of treatment. Mortality among patients treated with VACM therapy was 45.2% (95% CI: 27.32–63.97.Conclusions: The results of our own study confirm the results of previous studies which showed an acceptable FCR among non-trauma patients who were treated with VACM therapy. VACM therapy currently appears to be the treatment regime of choice for patients with OA requiring TAC.

The routine use of prosthetic mesh in austere environments: dogma vs data.

Science.gov (United States)

Kuckelman, John P; Barron, Morgan R; Blair, Kelly; Martin, Matthew J

2016-05-01

Mesh repair has become the standard in adult hernia repairs. Mesh infection is an uncommon but potentially devastating complication. Currently, there is widespread dogma against the use of prosthetic mesh (PM) in deployed or austere environments but little available data to support or refute this bias. Retrospective review of all hernia repairs over 1 year in a forward deployed surgical unit in Afghanistan. Demographics, hernia type, repair performed, and mesh type were evaluated. Follow-up was completed up to 6 weeks and then as needed for up to a year, and complications to include infection were recorded. Sixty-six patients were identified, mean age was 38 (range 3 to 80) and 98% were male. Single-dose perioperative antibiotics and standard sterile technique were used in all cases. The majority (70%) had PM placed. The mean operative time was 54 min, and mean estimated blood loss was less than 25 cm(3). The vast majority of our hernias were inguinal (95%) with 1 ventral and 2 umbilical hernias. In the PM group, there were no surgical site infections, no mesh infections, and no mesh explantation or reoperation. There were no recurrences in either group identified at up to 1-year postoperation. There was no statistically significant difference in any outcome measure between the PM and no-PM groups. The use of PM for hernia repairs in the austere or forward environment appears safe and did not increase the risk of wound infection, mesh infections, or recurrence. Published by Elsevier Inc.

Mesh complications and failure rates after transvaginal mesh repair compared with abdominal or laparoscopic sacrocolpopexy and to native tissue repair in treating apical prolapse.

Science.gov (United States)

Dandolu, Vani; Akiyama, Megumi; Allenback, Gayle; Pathak, Prathamesh

2017-02-01

Our objective was to quantitate the extent of complications and failure rate for apical prolapse repair with transvaginal mesh (TVM) use versus sacrocolpopexy over a minimum of 2 years of follow-up. Truven CCAE and Medicare Supplemental databases 2008-2013 were used for analysis. Patients with apical prolapse repair via transvaginal mesh (TVMR), abdominal sacrocolpopexy (ASCP), laparoscopic sacrocolpopexy (LSCP), or native tissue repair (NTR) and continuously enrolled for years were in the study cohort. Surgical failures were identified by reoperation for any prolapse or subsequent use of pessary. SAS® 9.3 was used for analysis. Mesh removal/revision was reported highest in TVMR (5.1 %), followed by LSCP (1.7 %) and ASCP (1.2 %). In those with concomitant sling, combined rates for mesh/sling revision were high, at 9.0 % in TVMR + sling, 5.6 % in ASCP + sling, and 4.5 % LSCP + sling. Sling-alone cases reported a 3.5 % revision rate. Pelvic pain (16.4-22.7 %) and dyspareunia (5.6-7.5 %) were high in all three approaches for apical prolapse repairs. Reoperation for apical prolapse was more common for TVMR (2.9 %) compared with NTR (2.3 %) [odds ratio (OR) 1.27; confidence interval (CI) 1.1-1.47; p 0.002]. Both ASCP and LSCP were superior to NTR (ASCP 1.5 %, OR 0.63, CI 0.46-0.86; p 0.003) and LSCP 1.8 % (OR 0.79, CI 0.62-1.01; p 0.07). Overall prolapse recurrence, as indicated by any compartment surgery for prolapse and/or pessary use, was also noted highest in TVMR (5.9 % OR 1.23, CI 1.11-1.36; p mesh is used for repair, mesh revision is highest with TVMR and lowest with ASCP.

Monitoring and evaluation of wire mesh forming life

Science.gov (United States)

Enemuoh, Emmanuel U.; Zhao, Ping; Kadlec, Alec

2018-03-01

Forming tables are used with stainless steel wire mesh conveyor belts to produce variety of products. The forming tables will typically run continuously for several days, with some hours of scheduled downtime for maintenance, cleaning and part replacement after several weeks of operation. The wire mesh conveyor belts show large variation in their remaining life due to associated variations in their nominal thicknesses. Currently the industry is dependent on seasoned operators to determine the replacement time for the wire mesh formers. The drawback of this approach is inconsistency in judgements made by different operators and lack of data knowledge that can be used to develop decision making system that will be more consistent with wire mesh life prediction and replacement time. In this study, diagnostic measurements about the health of wire mesh former is investigated and developed. The wire mesh quality characteristics considered are thermal measurement, tension property, gage thickness, and wire mesh wear. The results show that real time thermal sensor and wear measurements would provide suitable data for the estimation of wire mesh failure, therefore, can be used as a diagnostic parameter for developing structural health monitoring (SHM) system for stainless steel wire mesh formers.

The mesh controversy [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Joshua A. Cohn

2016-09-01

Full Text Available Pelvic organ prolapse and stress urinary incontinence are common conditions for which approximately 11% of women will undergo surgical intervention in their lifetime. The use of vaginal mesh for pelvic organ prolapse and stress urinary incontinence rose rapidly in the early 2000s as over 100 mesh products were introduced into the clinical armamentarium with little regulatory oversight for their use. US Food and Drug Administration Public Health Notifications in 2008 and 2011, as well as reclassification of transvaginal mesh for prolapse to class III in early 2016, were a response to debilitating complications associated with transvaginal mesh placement in many women. The midurethral sling has not been subject to the same reclassification and continues to be endorsed as the “gold standard” for surgical management of stress urinary incontinence by subspecialty societies. However, litigators have not differentiated between mesh for prolapse and mesh for incontinence. As such, all mesh, including that placed for stress urinary incontinence, faces continued controversy amidst an uncertain future. In this article, we review the background of the mesh controversy, recent developments, and the anticipated role of mesh in surgery for prolapse and stress urinary incontinence going forward.

Feature-Sensitive Tetrahedral Mesh Generation with Guaranteed Quality

OpenAIRE

Wang, Jun; Yu, Zeyun

2012-01-01

Tetrahedral meshes are being extensively used in finite element methods (FEM). This paper proposes an algorithm to generate feature-sensitive and high-quality tetrahedral meshes from an arbitrary surface mesh model. A top-down octree subdivision is conducted on the surface mesh and a set of tetrahedra are constructed using adaptive body-centered cubic (BCC) lattices. Special treatments are given to the tetrahedra near the surface such that the quality of the resulting tetrahedral mesh is prov...

Surgical management of a De Garengeot’s hernia using a biologic mesh: A case report and review of literature

Directory of Open Access Journals (Sweden)

Amandine Klipfel

2017-01-01

Conclusion: The De Garengeot hernia is an uncommon differential diagnosis for patients presenting with clinical signs of strangled femoral hernia. Although hernia repairs with a synthetic mesh in the presence of appendicitis have been reported, we describe a case of femoral hernia repair using a biologic mesh, in a patient with a De Garengot hernia.

Laser patterned carbon–polyethylene mesh electrodes for wound diagnostics

Energy Technology Data Exchange (ETDEWEB)

Phair, Jolene; Joshi, Mayank; Benson, John; McDonald, Damian; Davis, James, E-mail: james.davis@ulster.ac.uk

2014-02-14

Carbon loaded polyethylene films were selected as the base substrate for a mechanically flexible and conductive sensing material for use wound monitoring technologies. The films were processed using laser ablation of the surface to increase the effective surface area of the electrode and then subject to an oxidative electrochemical etch to improve the electron transfer kinetics. The surface morphology of the resulting films was analysed and the electrode performance in relation to monitoring uric acid, a key wound biomarker, was optimized. A prototype smart bandage was designed, based on interfacing the mesh to a portable potentiostat, and the response to urate and potential interferences assessed. - Highlights: • Innovative use of a carbon–polyethylene mesh for wound sensing applications. • Electroanalytical characterisation of a mechanically flexible conductive film. • Design and preliminary characterisation of an integrated smart bandage.

Laser patterned carbon–polyethylene mesh electrodes for wound diagnostics

International Nuclear Information System (INIS)

Phair, Jolene; Joshi, Mayank; Benson, John; McDonald, Damian; Davis, James

2014-01-01

Carbon loaded polyethylene films were selected as the base substrate for a mechanically flexible and conductive sensing material for use wound monitoring technologies. The films were processed using laser ablation of the surface to increase the effective surface area of the electrode and then subject to an oxidative electrochemical etch to improve the electron transfer kinetics. The surface morphology of the resulting films was analysed and the electrode performance in relation to monitoring uric acid, a key wound biomarker, was optimized. A prototype smart bandage was designed, based on interfacing the mesh to a portable potentiostat, and the response to urate and potential interferences assessed. - Highlights: • Innovative use of a carbon–polyethylene mesh for wound sensing applications. • Electroanalytical characterisation of a mechanically flexible conductive film. • Design and preliminary characterisation of an integrated smart bandage

Protection from radiation enteritis by an absorbable polyglycolic acid mesh sling

International Nuclear Information System (INIS)

Devereux, D.F.; Thompson, D.; Sandhaus, L.; Sweeney, W.; Haas, A.

1987-01-01

Patients with malignant tumors of the pelvis who cannot be cured surgically often are treated with radiation after surgery. A devastating side effect of this treatment is radiation-associated small bowel injury (RASBI). The purpose of this study was to test the hypothesis that removal of the small bowel from the radiation field would protect it against RASBI. Twenty cebus monkeys underwent low anterior resection. In 10 animals an absorbable polyglycolic acid (PGA) mesh was sewn circumferentially around the interior of the abdominal cavity as a supporting apron, which prevented the small bowel's descent into the pelvis. The other 10 monkeys did not receive the mesh. All animals received 2000 rads by linear acceleration in a single dose. Twenty-four-hour stool fat, serum vitamin B12, and other serum values were obtained during the study. Animals were sacrificed after 1, 2, 3, 6, and 12 months, and the small bowel and rectum were examined histologically in a blind manner. Two monkeys who did not undergo surgery, or exposure to radiation served as controls. At all sacrifice periods, the animals with PGA mesh slings demonstrated normal small bowel function and histologic structure. Animals without mesh slings had abnormal stool and blood values at 1 month, and by 2 months all had died of small bowel necrosis. The animals that received the slings had no evidence of infection or obstruction, and by 6 months all evidence of the mesh was gone. Support of the small bowel out of the pelvis by an absorbable PGA mesh sling protects against RASBI and is without apparent complications

Data-Parallel Mesh Connected Components Labeling and Analysis

Energy Technology Data Exchange (ETDEWEB)

Harrison, Cyrus; Childs, Hank; Gaither, Kelly

2011-04-10

We present a data-parallel algorithm for identifying and labeling the connected sub-meshes within a domain-decomposed 3D mesh. The identification task is challenging in a distributed-memory parallel setting because connectivity is transitive and the cells composing each sub-mesh may span many or all processors. Our algorithm employs a multi-stage application of the Union-find algorithm and a spatial partitioning scheme to efficiently merge information across processors and produce a global labeling of connected sub-meshes. Marking each vertex with its corresponding sub-mesh label allows us to isolate mesh features based on topology, enabling new analysis capabilities. We briefly discuss two specific applications of the algorithm and present results from a weak scaling study. We demonstrate the algorithm at concurrency levels up to 2197 cores and analyze meshes containing up to 68 billion cells.

Reduced order modelling techniques for mesh movement strategies as applied to fluid structure interactions

CSIR Research Space (South Africa)

Bogaers, Alfred EJ

2010-01-01

Full Text Available of Laplacian or Bi-harmonic equations [7], radial basis function (RBF) interpolation [3, 15] or through mesh optimization [1, 6]. Despite the successes of these algorithms in reducing the frequency and necessity for re- meshing, they still account for a... simulations of a real system. What makes POD remarkable is that the selected modes are not only appropriate but make up the optimal linear basis for describing any given system. POD has been applied in a wide range of disciplines including image processing...

Obtuse triangle suppression in anisotropic meshes

KAUST Repository

Sun, Feng; Choi, Yi King; Wang, Wen Ping; Yan, Dongming; Liu, Yang; Lé vy, Bruno L.

2011-01-01

Anisotropic triangle meshes are used for efficient approximation of surfaces and flow data in finite element analysis, and in these applications it is desirable to have as few obtuse triangles as possible to reduce the discretization error. We present a variational approach to suppressing obtuse triangles in anisotropic meshes. Specifically, we introduce a hexagonal Minkowski metric, which is sensitive to triangle orientation, to give a new formulation of the centroidal Voronoi tessellation (CVT) method. Furthermore, we prove several relevant properties of the CVT method with the newly introduced metric. Experiments show that our algorithm produces anisotropic meshes with much fewer obtuse triangles than using existing methods while maintaining mesh anisotropy. © 2011 Elsevier B.V. All rights reserved.

Obtuse triangle suppression in anisotropic meshes

KAUST Repository

Sun, Feng

2011-12-01

Anisotropic triangle meshes are used for efficient approximation of surfaces and flow data in finite element analysis, and in these applications it is desirable to have as few obtuse triangles as possible to reduce the discretization error. We present a variational approach to suppressing obtuse triangles in anisotropic meshes. Specifically, we introduce a hexagonal Minkowski metric, which is sensitive to triangle orientation, to give a new formulation of the centroidal Voronoi tessellation (CVT) method. Furthermore, we prove several relevant properties of the CVT method with the newly introduced metric. Experiments show that our algorithm produces anisotropic meshes with much fewer obtuse triangles than using existing methods while maintaining mesh anisotropy. © 2011 Elsevier B.V. All rights reserved.

A coarse-mesh nodal method-diffusive-mesh finite difference method

International Nuclear Information System (INIS)

Joo, H.; Nichols, W.R.

1994-01-01

Modern nodal methods have been successfully used for conventional light water reactor core analyses where the homogenized, node average cross sections (XSs) and the flux discontinuity factors (DFs) based on equivalence theory can reliably predict core behavior. For other types of cores and other geometries characterized by tightly-coupled, heterogeneous core configurations, the intranodal flux shapes obtained from a homogenized nodal problem may not accurately portray steep flux gradients near fuel assembly interfaces or various reactivity control elements. This may require extreme values of DFs (either very large, very small, or even negative) to achieve a desired solution accuracy. Extreme values of DFs, however, can disrupt the convergence of the iterative methods used to solve for the node average fluxes, and can lead to a difficulty in interpolating adjacent DF values. Several attempts to remedy the problem have been made, but nothing has been satisfactory. A new coarse-mesh nodal scheme called the Diffusive-Mesh Finite Difference (DMFD) technique, as contrasted with the coarse-mesh finite difference (CMFD) technique, has been developed to resolve this problem. This new technique and the development of a few-group, multidimensional kinetics computer program are described in this paper

Transvaginal six-arm mesh OPUR in women with apical pelvic organ prolapse - analysis of short-term results, pelvic floor ultrasound evaluation.

Science.gov (United States)

Kluz, Tomasz; Wlaźlak, Edyta; Surkont, Grzegorz

2017-01-01

Analysis of feasibility, efficacy and short-term results after six-arm transvaginal mesh OPUR implantation in women with apical prolapse. The same surgeon operated all of 39 women using mesh OPUR. Preoperatively patients had a standardized interview and clinical examination. Intraoperative and postoperative complications were analyzed. Postoperative evaluation included standardized interview, clinical examination and standardized pelvic floor ultrasound performed with 2D transvaginal probe and 4D abdominal probe. There was no complication that needed operative intervention. Hematomas in 3 patients resolved spontaneously. Transient voiding difficulties which lasted less than 7 days were observed in 5 patients. No erosion was observed. Comparison of pre- and postoperative results in 34 women revealed that in all 3 compartments improvement in POP-Q scale was statistically significant (p mesh needed re-operation. During PFS-TV in 94.1% of patients urethra was normobile or hypermobile. In all of the patients urethral end of the mesh was positioned far enough from the middle part of the urethra (ultrasound) to implant suburethral sling without risk of collision. Sexually active women did not inform of any important discomfort or pain during intercourse. It seems that six-arm OPUR mesh, if implanted under strict surgical rules, gives low risk of complications and high chance to successfully reduce POP symptoms in short term after the operation. It seems that OPUR mesh should not have negative influence on the results after anti-incontinence suburethral sling.

Percutaneous Vertebral Augmentation with Polyethylene Mesh and Allograft Bone for Traumatic Thoracolumbar Fractures

Directory of Open Access Journals (Sweden)

C. Schulz

2015-01-01

Full Text Available Purpose. In cases of traumatic thoracolumbar fractures, percutaneous vertebral augmentation can be used in addition to posterior stabilisation. The use of an augmentation technique with a bone-filled polyethylene mesh as a stand-alone treatment for traumatic vertebral fractures has not yet been investigated. Methods. In this retrospective study, 17 patients with acute type A3.1 fractures of the thoracic or lumbar spine underwent stand-alone augmentation with mesh and allograft bone and were followed up for one year using pain scales and sagittal endplate angles. Results. From before surgery to 12 months after surgery, pain and physical function improved significantly, as indicated by an improvement in the median VAS score and in the median pain and work scale scores. From before to immediately after surgery, all patients showed a significant improvement in mean mono- and bisegmental kyphoses. During the one-year period, there was a significant loss of correction. Conclusions. Based on this data a stand-alone approach with vertebral augmentation with polyethylene mesh and allograft bone is not a suitable therapy option for incomplete burst fractures for a young patient collective.

Image-Based Geometric Modeling and Mesh Generation

CERN Document Server

2013-01-01

As a new interdisciplinary research area, “image-based geometric modeling and mesh generation” integrates image processing, geometric modeling and mesh generation with finite element method (FEM) to solve problems in computational biomedicine, materials sciences and engineering. It is well known that FEM is currently well-developed and efficient, but mesh generation for complex geometries (e.g., the human body) still takes about 80% of the total analysis time and is the major obstacle to reduce the total computation time. It is mainly because none of the traditional approaches is sufficient to effectively construct finite element meshes for arbitrarily complicated domains, and generally a great deal of manual interaction is involved in mesh generation. This contributed volume, the first for such an interdisciplinary topic, collects the latest research by experts in this area. These papers cover a broad range of topics, including medical imaging, image alignment and segmentation, image-to-mesh conversion,...

Improving MeSH classification of biomedical articles using citation contexts.

Science.gov (United States)

Aljaber, Bader; Martinez, David; Stokes, Nicola; Bailey, James

2011-10-01

Medical Subject Headings (MeSH) are used to index the majority of databases generated by the National Library of Medicine. Essentially, MeSH terms are designed to make information, such as scientific articles, more retrievable and assessable to users of systems such as PubMed. This paper proposes a novel method for automating the assignment of biomedical publications with MeSH terms that takes advantage of citation references to these publications. Our findings show that analysing the citation references that point to a document can provide a useful source of terms that are not present in the document. The use of these citation contexts, as they are known, can thus help to provide a richer document feature representation, which in turn can help improve text mining and information retrieval applications, in our case MeSH term classification. In this paper, we also explore new methods of selecting and utilising citation contexts. In particular, we assess the effect of weighting the importance of citation terms (found in the citation contexts) according to two aspects: (i) the section of the paper they appear in and (ii) their distance to the citation marker. We conduct intrinsic and extrinsic evaluations of citation term quality. For the intrinsic evaluation, we rely on the UMLS Metathesaurus conceptual database to explore the semantic characteristics of the mined citation terms. We also analyse the "informativeness" of these terms using a class-entropy measure. For the extrinsic evaluation, we run a series of automatic document classification experiments over MeSH terms. Our experimental evaluation shows that citation contexts contain terms that are related to the original document, and that the integration of this knowledge results in better classification performance compared to two state-of-the-art MeSH classification systems: MeSHUP and MTI. Our experiments also demonstrate that the consideration of Section and Distance factors can lead to statistically

Inguinal Hernia Repair Using Self-adhering Sutureless Mesh: Adhesix™: A 3-Year Follow-up with Low Chronic Pain and Recurrence Rate.

Science.gov (United States)

Tabbara, Malek; Genser, Laurent; Bossi, Manuela; Barat, Maxime; Polliand, Claude; Carandina, Sergio; Barrat, Christophe

2016-02-01

To review our experience and outcomes after inguinal hernia repair using the lightweight self-adhering sutureless mesh "Adhesix™" and demonstrate the safety and efficacy of this mesh. This is a 3-year retrospective study that included 143 consecutive patients who underwent 149 inguinal hernia repairs at our department of surgery. All hernias were repaired using a modified Lichtenstein technique. Preoperative, perioperative, and postoperative data were prospectively collected. Incidence of chronic pain, postoperative complications, recurrence, and patient satisfaction were assessed three years postoperatively by conducting a telephone survey. We had 143 patients with a mean age of 58 years (17-84), who underwent 149 hernia repairs using the Adhesix™ mesh. Ninety-two per cent (131 patients) were males. Only 10 patients (7%) had a postoperative pain for more than three years. In our series, neither age nor gender was predictive of postoperative pain. Only one patient had a hematoma lasting for more than one month and only four patients (2.8%) had a recurrence of their hernia within three years of their initial surgery. Ninety per cent of the patient expressed their satisfaction when surveyed three years after their surgery. In conclusion, the use of the self-adhering sutureless mesh for inguinal hernia repair has been proving itself as effective as the traditional mesh. Adhesix™ is associated with low chronic pain rate, recurrence rate, and postoperative complications rate, and can be safely adopted as the sole technique for inguinal hernia repair.

Preliminary report of a sutureless onlay technique for incisional hernia repair using fibrin glue alone for mesh fixation.

Science.gov (United States)

Stoikes, Nathaniel; Webb, David; Powell, Ben; Voeller, Guy

2013-11-01

The Rives repair for ventral/incisional (V/I) hernias involves sublay mesh placement requiring retrorectus dissection and transfascial stitches. Chevrel described a repair by onlaying mesh after a unique primary fascial closure. Although Chevrel fixated mesh to the anterior fascia with sutures, he used fibrin glue for fascial closure reinforcement. We describe an onlay technique with mesh fixated to the anterior fascia solely with fibrin glue without suture fixation. From January 2010 to January 2012, 50 patients underwent a V/I hernia onlay technique with fibrin glue mesh fixation. Records were reviewed for technical details, demographics, mesh characteristics, and postoperative outcomes. Primary fascial closure with interrupted permanent suture was done with or without myofascial advancement flaps. Onlay polypropylene mesh was placed providing 8 cm of overlap. Fibrin glue was applied over the prosthesis and subcutaneous drains were placed. Mean age was 62.4 years. Mean body mass index was 30.1 kg/m(2). Average mesh size was 14.5 cm × 19.1 cm. Mean operative time was 144.4 minutes (range, 38 to 316 minutes). Mean discharge was postoperative Day 2.9 (range, 0 to 15 days). Morbidity included eight seromas, one hematoma, and three wound infections. Seventeen patients required components separation. Mean follow-up was 19.5 months with no recurrences. This is the first series describing fibrin glue alone for mesh fixation for V/I hernia repair. It allows for immediate prosthesis fixation to the anterior fascia. Early results are promising. Potential advantages include less operative time, less technical difficulty, and less long-term pain. A prospective trial is needed to evaluate this approach.

Anterior Z-plate and titanic mesh fixation for acute burst thoracolumbar fracture.

Science.gov (United States)

Xu, Jian-Guang; Zeng, Bing-Fang; Zhou, Wei; Kong, Wei-Qing; Fu, Yi-Shan; Zhao, Bi-Zeng; Zhang, Tao; Lian, Xiao-Feng

2011-04-01

A retrospective study. To evaluate the clinical outcome, effectiveness, and security of the surgical management of acute thoracolumbar burst fracture with corpectomy, titanic mesh autograft, and Z-plate fixation by anterior approach. Many surgical methods were adopted to treat acute burst thoracolumbar fracture. But the optimal surgical management remains controversial. A retrospective review of a consecutive series of 48 patients with thoracolumbar burst fracture treated with anterior corpectomy, titanic mesh autograft, and Z-plate internal fixation was carried out. Preoperative clinical and radiographic data of all cases were originally collected. Surgical indications were motor neurologic deficit and thoracolumbar column instability. Twenty-two patients (45.8%) with acute thoracolumbar burst fractures presented with a neurologic deficit. The postoperative recovery of neural function, restoration of anterior cortex collapse, kyphotic angle, and spinal canal compromise were observed. The preoperative kyphotic angle was improved to a mean of 5.6°, radiographic height restored to 95.8% of the adjacent normal levels, and canal compromise was 0%. None of the patients had neurologic deterioration. Mean follow-up time was 32.4 months (range, 24-47 months). All 22 patients with neurologic deficit demonstrated at least one Frankel grade improvement on final observation, with 16 (73%) patients had accomplished complete neurologic recovery. Forty-six (96%) patients reported minimal or no pain at final follow-up observation, and 40 (83%) patients who had been working before injury returned to original work. The authors considered spinal cord decompression with anterior corpectomy and stability reconstruction with titanic mesh autograft and Z-plate fixation at same time in one incision as an effective technique for unstable thoracolumbar burst fracture with and without neurologic deficit.

Clinical observation of a modified surgical method: posterior vaginal mesh suspension of female rectocele with intractable constipation.

Science.gov (United States)

Hong, Ling; Li, Huai-Fang; Sun, Jing; Zhu, Jian-Long; Ai, Gui-hai; Li, Li; Zhang, Bo; Chi, Feng-li; Tong, Xiao-Wen

2012-01-01

To explore the feasibility and effectiveness of a modified posterior vaginal mesh suspension method in treating female rectocele with intractable constipation. Descriptive study (Canadian Task Force classification II-3). The study was performed in the Study Center for Female Pelvic Dysfunction Disease, Department of Obstetrics and Gynecology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China. The Study Center includes 15 physicians, most of whom have received advanced training in pelvic floor dysfunctional disease and can skillfully perform many types of operations in patients with such disease. Almost 1500 operations to treat pelvic floor dysfunctional disease are performed every year at the center. Thirty-six women with rectocele with intractable constipation. Posterior vaginal mesh suspension. All patients were followed up for 15 to 36 months. In 29 patients, the condition was cured completely; in 5 patients it had improved; and in 2 patients, the intervention had no effect. Insofar as recovery and improved results, the overall effectiveness rate was 94.4%. Posterior vaginal mesh suspension is an effective, harmless, and convenient method for treatment of female rectocele with intractable constipation. It has positive short-term curative effects, with few complications and sequelae. However, the long-term effects of posterior vaginal mesh suspension should be evaluated. Copyright © 2012 AAGL. Published by Elsevier Inc. All rights reserved.

Simplified Technique for Incorporating a Metal Mesh into Record Bases for Mandibular Implant Overdentures.

Science.gov (United States)

Godoy, Antonio; Siegel, Sharon C

2015-12-01

Mandibular implant-retained overdentures have become the standard of care for patients with mandibular complete edentulism. As part of the treatment, the mandibular implant-retained overdenture may require a metal mesh framework to be incorporated to strengthen the denture and avoid fracture of the prosthesis. Integrating the metal mesh framework as part of the acrylic record base and wax occlusion rim before the jaw relation procedure will avoid the distortion of the record base and will minimize the chances of processing errors. A simplified method to incorporate the mesh into the record base and occlusion rim is presented in this technique article. © 2015 by the American College of Prosthodontists.

Dynamic Mesh Adaptation for Front Evolution Using Discontinuous Galerkin Based Weighted Condition Number Mesh Relaxation

Energy Technology Data Exchange (ETDEWEB)

Greene, Patrick T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schofield, Samuel P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nourgaliev, Robert [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-06-21

A new mesh smoothing method designed to cluster mesh cells near a dynamically evolving interface is presented. The method is based on weighted condition number mesh relaxation with the weight function being computed from a level set representation of the interface. The weight function is expressed as a Taylor series based discontinuous Galerkin projection, which makes the computation of the derivatives of the weight function needed during the condition number optimization process a trivial matter. For cases when a level set is not available, a fast method for generating a low-order level set from discrete cell-centered elds, such as a volume fraction or index function, is provided. Results show that the low-order level set works equally well for the weight function as the actual level set. Meshes generated for a number of interface geometries are presented, including cases with multiple level sets. Dynamic cases for moving interfaces are presented to demonstrate the method's potential usefulness to arbitrary Lagrangian Eulerian (ALE) methods.

Configuring the Mesh Size, Side Taper and Wing Depth of Penaeid Trawls to Reduce Environmental Impacts

Science.gov (United States)

Broadhurst, Matt K.; Sterling, David J.; Millar, Russell B.

2014-01-01

The effects of reducing mesh size while concomitantly varying the side taper and wing depth of a generic penaeid-trawl body were investigated to improve engineering performance and minimize bycatch. Five trawl bodies (with the same codends) were tested across various environmental (e.g. depth and current) and biological (e.g. species and sizes) conditions. The first trawl body comprised 41-mm mesh and represented conventional designs (termed the ‘41 long deep-wing'), while the remaining trawl bodies were made from 32-mm mesh and differed only in their side tapers, and therefore length (i.e. 1N3B or ‘long’ and ∼28o to the tow direction vs 1N5B or ‘short’ and ∼35o) and wing depths (‘deep’–97 T vs ‘shallow’–60 T). There were incremental drag reductions (and therefore fuel savings – by up to 18 and 12% per h and ha trawled) associated with reducing twine area via either modification, and subsequently minimizing otter-board area in attempts to standardize spread. Side taper and wing depth had interactive and varied effects on species selectivity, but compared to the conventional 41 long deep-wing trawl, the 32 short shallow-wing trawl (i.e. the least twine area) reduced the total bycatch by 57% (attributed to more fish swimming forward and escaping). In most cases, all small-meshed trawls also caught more smaller school prawns Metapenaeus macleayi but to decrease this effect it should be possible to increase mesh size slightly, while still maintaining the above engineering benefits and species selectivity. The results support precisely optimizing mesh size as a precursor to any other anterior penaeid-trawl modifications designed to improve environmental performance. PMID:24911786

Geometrically Consistent Mesh Modification

KAUST Repository

Bonito, A.

2010-01-01

A new paradigm of adaptivity is to execute refinement, coarsening, and smoothing of meshes on manifolds with incomplete information about their geometry and yet preserve position and curvature accuracy. We refer to this collectively as geometrically consistent (GC) mesh modification. We discuss the concept of discrete GC, show the failure of naive approaches, and propose and analyze a simple algorithm that is GC and accuracy preserving. © 2010 Society for Industrial and Applied Mathematics.

A prospective study of transobturator tape as treatment for stress urinary incontinence after transvaginal mesh repair.

Science.gov (United States)

Lau, Hui-Hsuan; Su, Tsung-Hsien; Huang, Wen-Chu; Hsieh, Ching-Hung; Su, Chin-Hui; Chang, Rhu-Chu

2013-10-01

The transobturator suburethral sling is a common surgical treatment for stress urinary incontinence (SUI). In patients with incontinence after trocar-guided transvaginal mesh repair (Prolift), data on outcome remain limited. In the present study, we hypothesized that transobturator tape in such cases is assumed to be as effective as surgery alone. This was a prospective analysis of outcomes of transobturator slings in women who had undergone transvaginal mesh repair and in those who underwent sling surgery alone (controls). Objective cure was defined as the absence of urinary leakage during the stress test at filling cystometry and a negative cough test during pelvic examination. The success rates were evaluated 3-6 months postoperatively. One hundred women were recruited for the study. Compared to the control group, women after transvaginal mesh repair had a significantly lower objective success rate (62 vs 86%, p = 0.005) and poorer bladder neck mobility (0.5 ± 0.8 vs 1.1 ± 0.5 cm, p = 0.001). The transobturator sling has lower objective success rate in women after transvaginal mesh that may be due to decreased bladder neck mobility. Patients with post-mesh repair SUI who opt for sling surgery should be informed of these less satisfactory outcomes during preoperative counseling.

Multi-phase Volume Segmentation with Tetrahedral Mesh

DEFF Research Database (Denmark)

Nguyen Trung, Tuan; Dahl, Vedrana Andersen; Bærentzen, Jakob Andreas

Volume segmentation is efficient for reconstructing material structure, which is important for several analyses, e.g. simulation with finite element method, measurement of quantitative information like surface area, surface curvature, volume, etc. We are concerned about the representations of the 3......D volumes, which can be categorized into two groups: fixed voxel grids [1] and unstructured meshes [2]. Among these two representations, the voxel grids are more popular since manipulating a fixed grid is easier than an unstructured mesh, but they are less efficient for quantitative measurements....... In many cases, the voxel grids are converted to explicit meshes, however the conversion may reduce the accuracy of the segmentations, and the effort for meshing is also not trivial. On the other side, methods using unstructured meshes have difficulty in handling topology changes. To reduce the complexity...

High-grade hemorrhoids requiring surgical treatment are common after laparoscopic ventral mesh rectopexy

NARCIS (Netherlands)

van Iersel, J. J.; Formijne Jonkers, H. A.; Verheijen, P. M.; Draaisma, W. A.; Consten, E. C J; Broeders, I. A M J

2016-01-01

Purpose: To describe patients developing grade III and IV hemorrhoids requiring surgery after laparoscopic ventral mesh rectopexy (LVMR) and to explore the relationship between developing such hemorrhoids and recurrence of rectal prolapse after LVMR. Methods: All consecutive patients receiving LVMR

MHD simulations on an unstructured mesh

International Nuclear Information System (INIS)

Strauss, H.R.; Park, W.

1996-01-01

We describe work on a full MHD code using an unstructured mesh. MH3D++ is an extension of the PPPL MH3D resistive full MHD code. MH3D++ replaces the structured mesh and finite difference / fourier discretization of MH3D with an unstructured mesh and finite element / fourier discretization. Low level routines which perform differential operations, solution of PDEs such as Poisson's equation, and graphics, are encapsulated in C++ objects to isolate the finite element operations from the higher level code. The high level code is the same, whether it is run in structured or unstructured mesh versions. This allows the unstructured mesh version to be benchmarked against the structured mesh version. As a preliminary example, disruptions in DIIID reverse shear equilibria are studied numerically with the MH3D++ code. Numerical equilibria were first produced starting with an EQDSK file containing equilibrium data of a DIII-D L-mode negative central shear discharge. Using these equilibria, the linearized equations are time advanced to get the toroidal mode number n = 1 linear growth rate and eigenmode, which is resistively unstable. The equilibrium and linear mode are used to initialize 3D nonlinear runs. An example shows poloidal slices of 3D pressure surfaces: initially, on the left, and at an intermediate time, on the right

Capacity Analysis of Wireless Mesh Networks

Directory of Open Access Journals (Sweden)

M. I. Gumel

2012-06-01

Full Text Available The next generation wireless networks experienced a great development with emergence of wireless mesh networks (WMNs, which can be regarded as a realistic solution that provides wireless broadband access. The limited available bandwidth makes capacity analysis of the network very essential. While the network offers broadband wireless access to community and enterprise users, the problems that limit the network capacity must be addressed to exploit the optimum network performance. The wireless mesh network capacity analysis shows that the throughput of each mesh node degrades in order of l/n with increasing number of nodes (n in a linear topology. The degradation is found to be higher in a fully mesh network as a result of increase in interference and MAC layer contention in the network.

Field-aligned mesh joinery

OpenAIRE

Cignoni, Paolo; Pietroni, Nico; Malomo, Luigi

2014-01-01

Mesh joinery is an innovative method to produce illustrative shape approximations suitable for fabrication. Mesh joinery is capable of producing complex fabricable structures in an efficient and visually pleasing manner. We represent an input geometry as a set of planar pieces arranged to compose a rigid structure, by exploiting an efficient slit mechanism. Since slices are planar, to fabricate them a standard 2D cutting system is enough. We automatically arrange slices according to a smooth ...

The effects of vaginal prolapse surgery using synthetic mesh on vaginal wall sensibility, vaginal vasocongestion, and sexual function: a prospective single-center study

NARCIS (Netherlands)

Weber, Maaike A.; Lakeman, Marielle M. E.; Laan, Ellen; Roovers, Jan-Paul W. R.

2014-01-01

Vaginal mesh surgery in patients with pelvic organ prolapse (POP) has been associated with sexual dysfunction. Implantation of synthetic mesh might damage vaginal innervation and vascularization, which could cause sexual dysfunction. We aim to evaluate the effects of vaginal mesh surgery on vaginal

Mesh three-dimensional arm orthosis with built-in ultrasound physiotherapy system

Science.gov (United States)

Kashapova, R. M.; Kashapov, R. N.; Kashapova, R. S.

2017-09-01

The possibility of using the built-in ultrasound physiotherapy system of the hand orthosis is explored in the work. The individual mesh orthosis from nylon 12 was manufactured by the 3D prototyping method on the installation of selective laser sintering SLS SPro 60HD. The applied technology of three-dimensional scanning made it possible to obtain a model of the patient’s hand and on the basis of it to build a virtual model of the mesh frame. In the course of the research, the developed system of ultrasound exposure was installed on the orthosis and its tests were carried out. As a result, the acceleration of the healing process and the reduction in the time of wearing orthosis were found.

Evaluation of the generality and accuracy of a new mesh morphing procedure for the human femur.

Science.gov (United States)

Grassi, Lorenzo; Hraiech, Najah; Schileo, Enrico; Ansaloni, Mauro; Rochette, Michel; Viceconti, Marco

2011-01-01

Various papers described mesh morphing techniques for computational biomechanics, but none of them provided a quantitative assessment of generality, robustness, automation, and accuracy in predicting strains. This study aims to quantitatively evaluate the performance of a novel mesh-morphing algorithm. A mesh-morphing algorithm based on radial-basis functions and on manual selection of corresponding landmarks on template and target was developed. The periosteal geometries of 100 femurs were derived from a computed tomography scan database and used to test the algorithm generality in producing finite element (FE) morphed meshes. A published benchmark, consisting of eight femurs for which in vitro strain measurements and standard FE model strain prediction accuracy were available, was used to assess the accuracy of morphed FE models in predicting strains. Relevant parameters were identified to test the algorithm robustness to operative conditions. Time and effort needed were evaluated to define the algorithm degree of automation. Morphing was successful for 95% of the specimens, with mesh quality indicators comparable to those of standard FE meshes. Accuracy of the morphed meshes in predicting strains was good (R(2)>0.9, RMSE%0.05) and partially to the number of landmark used. Producing a morphed mesh starting from the triangularized geometry of the specimen requires on average 10 min. The proposed method is general, robust, automated, and accurate enough to be used in bone FE modelling from diagnostic data, and prospectively in applications such as statistical shape modelling. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Pure transvaginal excision of mesh erosion involving the bladder.

Science.gov (United States)

Firoozi, Farzeen; Goldman, Howard B

2013-06-01

We present a pure transvaginal approach to the removal of eroded mesh involving the bladder secondary to placement of transvaginal mesh for management of pelvic organ prolapse (POP) using a mesh kit. Although technically challenging, we demonstrate the feasibility of a purely transvaginal approach, avoiding a potentially more morbid transabdominal approach. The video presents the surgical technique of pure transvaginal excision of mesh erosion involving the bladder after mesh placement using a prolapse kit was performed. This video shows that purely transvaginal removal of mesh erosion involving the bladder can be done safely and is feasible.

First human use of hybrid synthetic/biologic mesh in ventral hernia repair: a multicenter trial.

Science.gov (United States)

Bittner, James G; El-Hayek, Kevin; Strong, Andrew T; LaPinska, Melissa Phillips; Yoo, Jin S; Pauli, Eric M; Kroh, Matthew

2018-03-01

Mesh options for reinforcement of ventral/incisional hernia (VIH) repair include synthetic or biologic materials. While each material has known advantages and disadvantages, little is understood about outcomes when these materials are used in combination. This multicenter study reports on the first human use of a novel synthetic/biologic hybrid mesh (Zenapro ® Hybrid Hernia Repair Device) for VIH repair. This prospective, multicenter post-market clinical trial enrolled consecutive adults who underwent elective VIH repair with hybrid mesh placed in the intraperitoneal or retromuscular/preperitoneal position. Patients were classified as Ventral Hernia Working Group (VHWG) grades 1-3 and had clean or clean-contaminated wounds. Outcomes of ventral and incisional hernia were compared using appropriate parametric tests. In all, 63 patients underwent VIH repair with hybrid mesh. Most were females (54.0%), had a mean age of 54.8 ± 10.9 years and mean body mass index of 34.5 ± 7.8 kg/m 2 , and classified as VHWG grade 2 (87.3%). Most defects were midline (92.1%) with a mean area of 106 ± 155 cm 2 . Cases were commonly classified as clean (92.1%) and were performed laparoscopically (60.3%). Primary fascial closure was achieved in 82.5% with 28.2% requiring component separation. Mesh location was frequently intraperitoneal (69.8%). Overall, 39% of patients available for follow-up at 12 months suffered surgical site events, which were generally more frequent after incisional hernia repair. Of these, seroma (23.7%) was most common, but few (8.5%) required procedural intervention. Other surgical site events that required procedural intervention included hematoma (1.7%), wound dehiscence (1.7%), and surgical site infection (3.4%). Recurrence rate was 6.8% (95% CI 2.2-16.6%) at 12-months postoperatively. Zenapro ® Hybrid Hernia Repair Device is safe and effective in VHWG grade 1-2 patients with clean wounds out to 12 months. Short-term outcomes and recurrence rate

Prospective, Randomized Study on the Use of a Prosthetic Mesh for Prevention of Parastomal Hernia of Permanent Colostomy.

Science.gov (United States)

Vierimaa, Mika; Klintrup, Kai; Biancari, Fausto; Victorzon, Mikael; Carpelan-Holmström, Monika; Kössi, Jyrki; Kellokumpu, Ilmo; Rauvala, Erkki; Ohtonen, Pasi; Mäkelä, Jyrki; Rautio, Tero

2015-10-01

Prophylactic placement of a mesh has been suggested to prevent parastomal hernia, but evidence to support this approach is scarce. The aim of this study was to evaluate whether laparoscopic placement of a prophylactic, dual-component, intraperitoneal onlay mesh around a colostomy is safe and prevents parastomal hernia formation after laparoscopic abdominoperineal resection. This is a prospective, multicenter, randomized controlled clinical trial. This study was conducted at 2 university and 3 central Finnish hospitals. From 2010 to 2013, 83 patients undergoing laparoscopic abdominoperineal resection for rectal cancer were recruited. After withdrawals and exclusions, the outcome of 70 patients, 35 patients in each study group, could be examined. In the intervention group, an end colostomy was created with placement of a intraperitoneal, dual-component onlay mesh and compared with a group with a traditional stoma. The main outcome measures were the incidence of clinically and radiologically detected parastomal hernias and their extent 12 months after surgery. Stoma-related morbidity and the need for surgical repair of parastomal hernia were secondary outcome measures. Parastomal hernia was observed by clinical inspection in 5 intervention patients (14.3%) and in 12 control patients (32.3%; p = 0.049). Surgical repair of parastomal hernia was performed in 1 control patient (3.2%) and in none of the patients in the intervention group. CT detected parastomal hernia in 18 intervention patients (51.4%) and in 17 control patients (53.1%; p = 1.00). The extent of hernias was similar according to European Hernia Society classification (p = 0.41). Colostomy-related morbidity (32.3% vs 14.3%; p = 0.140) did not differ between the study groups. The study was limited by its small size and short follow-up time. Prophylactic laparoscopic placement of intraperitoneal onlay mesh does not significantly reduce the overall risk of radiologically detected parastomal hernia after

Highly Symmetric and Congruently Tiled Meshes for Shells and Domes

Science.gov (United States)

Rasheed, Muhibur; Bajaj, Chandrajit

2016-01-01

We describe the generation of all possible shell and dome shapes that can be uniquely meshed (tiled) using a single type of mesh face (tile), and following a single meshing (tiling) rule that governs the mesh (tile) arrangement with maximal vertex, edge and face symmetries. Such tiling arrangements or congruently tiled meshed shapes, are frequently found in chemical forms (fullerenes or Bucky balls, crystals, quasi-crystals, virus nano shells or capsids), and synthetic shapes (cages, sports domes, modern architectural facades). Congruently tiled meshes are both aesthetic and complete, as they support maximal mesh symmetries with minimal complexity and possess simple generation rules. Here, we generate congruent tilings and meshed shape layouts that satisfy these optimality conditions. Further, the congruent meshes are uniquely mappable to an almost regular 3D polyhedron (or its dual polyhedron) and which exhibits face-transitive (and edge-transitive) congruency with at most two types of vertices (each type transitive to the other). The family of all such congruently meshed polyhedra create a new class of meshed shapes, beyond the well-studied regular, semi-regular and quasi-regular classes, and their duals (platonic, Catalan and Johnson). While our new mesh class is infinite, we prove that there exists a unique mesh parametrization, where each member of the class can be represented by two integer lattice variables, and moreover efficiently constructable. PMID:27563368

How to model wireless mesh networks topology

International Nuclear Information System (INIS)

Sanni, M L; Hashim, A A; Anwar, F; Ali, S; Ahmed, G S M

2013-01-01

The specification of network connectivity model or topology is the beginning of design and analysis in Computer Network researches. Wireless Mesh Networks is an autonomic network that is dynamically self-organised, self-configured while the mesh nodes establish automatic connectivity with the adjacent nodes in the relay network of wireless backbone routers. Researches in Wireless Mesh Networks range from node deployment to internetworking issues with sensor, Internet and cellular networks. These researches require modelling of relationships and interactions among nodes including technical characteristics of the links while satisfying the architectural requirements of the physical network. However, the existing topology generators model geographic topologies which constitute different architectures, thus may not be suitable in Wireless Mesh Networks scenarios. The existing methods of topology generation are explored, analysed and parameters for their characterisation are identified. Furthermore, an algorithm for the design of Wireless Mesh Networks topology based on square grid model is proposed in this paper. The performance of the topology generated is also evaluated. This research is particularly important in the generation of a close-to-real topology for ensuring relevance of design to the intended network and validity of results obtained in Wireless Mesh Networks researches

Comparative analysis of early adverse events of pelvic organ prolapse repair with or without transvaginal mesh using Clavien-Dindo classification.

Science.gov (United States)

Besser, Limor; Schwarzman, Polina; Mastrolia, Salvatore A; Rotem, Reut; Leron, Elad; Yohay, David; Weintraub, Adi Y

2018-04-10

To assess adverse events following surgical repair of pelvic organ prolapse (POP) with or without the use of transvaginal mesh. The present retrospective study was conducted among women who underwent surgical POP repair at Soroka University Medical Center, Beer Sheva, Israel, between January 1, 2013, and December 31, 2015. Patients underwent anterior and posterior colporrhaphy either with transvaginal mesh (Elevate Prolapse Repair System; American Medical Systems, Minnetonka, MN, USA) or without transvaginal mesh (native tissue repair). Perioperative adverse events were assessed using the Clavien-Dindo classification; multivariate regression models were constructed to predict minor and major adverse events. There were 111 women included; 35 were treated with transvaginal mesh, and 76 underwent native tissue repair. Women undergoing native tissue repair had a lower mean grade of cystocele (P=0.023) and a higher rate of urinary stress incontinence (P=0.017) than patients treated with transvaginal mesh. The duration of surgery (P=0.002), duration of hospitalization (Ptransvaginal mesh was not associated with increased odds of major or minor adverse events (P>0.05 for all models examined). Perioperative and postoperative adverse events were comparable regardless of the operative approach. © 2018 International Federation of Gynecology and Obstetrics.

Challenges in Second-Generation Wireless Mesh Networks

Directory of Open Access Journals (Sweden)

Pescapé Antonio

2008-01-01

Full Text Available Wireless mesh networks have the potential to provide ubiquitous high-speed Internet access at low costs. The good news is that initial deployments of WiFi meshes show the feasibility of providing ubiquitous Internet connectivity. However, their performance is far below the necessary and achievable limit. Moreover, users' subscription in the existing meshes is dismal even though the technical challenges to get connectivity are low. This paper provides an overview of the current status of mesh networks' deployment, and highlights the technical, economical, and social challenges that need to be addressed in the next years. As a proof-of-principle study, we discuss the above-mentioned challenges with reference to three real networks: (i MagNets, an operator-driven planned two-tier mesh network; (ii Berlin Freifunk network as a pure community-driven single-tier network; (iii Weimar Freifunk network, also a community-driven but two-tier network.

MeSH key terms for validation and annotation of gene expression clusters

Energy Technology Data Exchange (ETDEWEB)

Rechtsteiner, A. (Andreas); Rocha, L. M. (Luis Mateus)

2004-01-01

associated with MeSH terms. MeSH terms can be associated with genes through co-occurrence of these in MEDLINE citations, i.e. the genes occur in titles or abstracts and the MeSH terms are assigned by experts. To identify MeSH terms associated with a group of genes we used the tool MESHGENE developed at the Information Dynamics Lab at HP Labs (http://www-idl.hpl.hp.com/meshgene/). When presented with a list of human genes, MESHGENE uses some sophisticated techniques to search for these gene symbols in the titles and abstracts of all MEDLINE citations. MeSH terms and the number of co-occurrences can be retrieved. Gene symbols that are aliases of each other are pooled from several databases. This addresses the problem of synonymy, the fact that several symbols can refer to the same gene. MESHGENE employs some sophisticated algorithms that disregards symbols that are likely to be acronyms for other concepts than a gene. This addresses the problem of polysemy, i.e. possible multiple meanings of a gene symbol. We applied our approach to gene expression data from herpes virus infected human fibroblast cells. The data contains 12 time-points, between 1/2 hrs and 48 hrs after infection. Singular Value Decomposition was used to identify the dominant modes of expression. 75% of the variance in the expression data was captured by the first two modes, the first exhibiting a monotonly increasing expression pattern and the second a more transient pattern. Projection of the gene expression vectors onto this first two modes identified 3 statistically significant clusters of co-expressed genes. 500 genes from cluster 1 and 300 genes from clusters 2 and 3 each were uploaded to MESHGENE and the MeSH terms and co-occurrence values were retrieved. MeSH terms were also obtained for 5 groups of randomly selected genes with similar numbers of genes. The log was taken of the co-occurrence values and for each MeSH term these log co-occurrence values were summed for each group over the genes in that

SALOME PLATFORM and TetGen for Polyhedral Mesh Generation

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Yong; Park, Chan Eok; Kim, Shin Whan [KEPCO E and C Company, Inc., Daejeon (Korea, Republic of)

2014-05-15

SPACE and CUPID use the unstructured mesh and they also require reliable mesh generation system. The combination of CAD system and mesh generation system is necessary to cope with a large number of cells and the complex fluid system with structural materials inside. In the past, a CAD system Pro/Engineer and mesh generator Pointwise were evaluated for this application. But, the cost of those commercial CAD and mesh generator is sometimes a great burden. Therefore, efforts have been made to set up a mesh generation system with open source programs. The evaluation of the TetGen has been made in focusing the application for the polyhedral mesh generation. In this paper, SALOME will be evaluated for the efforts in conjunction with TetGen. In section 2, review will be made on the CAD and mesh generation capability of SALOME. SALOME and TetGen codes are being integrated to construct robust polyhedral mesh generator. Edge removal on the flat surface and vertex reattachment to the solid are two challenging tasks. It is worthwhile to point out that the Python script capability of the SALOME should be fully utilized for the future investigation.

Mesh requirements for neutron transport calculations

International Nuclear Information System (INIS)

Askew, J.R.

1967-07-01

Fine-structure calculations are reported for a cylindrical natural uranium-graphite cell using different solution methods (discrete ordinate and collision probability codes) and varying the spatial mesh. It is suggested that of formulations assuming the source constant in a mesh interval the differential approach is generally to be preferred. Due to cancellation between approximations made in the derivation of the finite difference equations and the errors in neglecting source variation, the discrete ordinate code gave a more accurate estimate of fine structure for a given mesh even for unusually coarse representations. (author)

Infection of PTFE mesh 15 years following pedicled TRAM flap breast reconstruction: mechanism and aetiology.

Science.gov (United States)

Elfaki, A; Gkorila, A; Khatib, M; Malata, C M

2018-01-01

The pedicled transverse rectus abdominis myocutaneous (TRAM) flap procedure is still widely used for breast reconstruction. The repair of the flap harvest site in the transverse rectus abdominis muscle and sheath is often assisted by the use of prosthetic meshes. This decreases the risk of abdominal wall weakness and herniation but, being a foreign body, it also carries the risk of infection. In this report, we describe the case of a 63-year-old patient who, whilst receiving chemotherapy for metastatic breast cancer, presented with an infected polytetrafluoroethylene mesh 15 years after pedicled TRAM flap immediate breast reconstruction. This necessitated mesh removal to treat the infection. Following a thorough review of the English literature, this is the longest recorded presentation of an abdominal prosthetic mesh infection. The mechanism and aetiology of such a late complication are discussed.

Improved mesh generator for the POISSON Group Codes

International Nuclear Information System (INIS)

Gupta, R.C.

1987-01-01

This paper describes the improved mesh generator of the POISSON Group Codes. These improvements enable one to have full control over the way the mesh is generated and in particular the way the mesh density is distributed throughout this model. A higher mesh density in certain regions coupled with a successively lower mesh density in others keeps the accuracy of the field computation high and the requirements on the computer time and computer memory low. The mesh is generated with the help of codes AUTOMESH and LATTICE; both have gone through a major upgrade. Modifications have also been made in the POISSON part of these codes. We shall present an example of a superconducting dipole magnet to explain how to use this code. The results of field computations are found to be reliable within a few parts in a hundred thousand even in such complex geometries

Reconstruction of Midface and Orbital Wall Defects After Maxillectomy and Orbital Content Preservation With Titanium Mesh and Fascia Lata: 3-Year Follow-Up.

Science.gov (United States)

Motiee-Langroudi, Maziar; Harirchi, Iraj; Amali, Amin; Jafari, Mehrdad

2015-12-01

To describe the authors' experience in the reconstruction of patients after total maxillectomy with preservation of orbital contents for maxillary tumors using titanium mesh and autogenous fascia lata, where no setting for free flap reconstruction is available. Twelve consecutive patients with paranasal sinus tumors underwent total maxillectomy without orbital exenterations and primary reconstruction. The defects were reconstructed by titanium mesh in combination with autogenous fascia lata in the orbital floor performed by 1 surgical team. Titanium mesh (0.2 mm thick) was contoured and fixed to reconstruct the orbital floor and obtain midface projection. Fascia lata was used to cover the titanium mesh along the orbital floor to prevent fat entrapment in the mesh holes. The most common pathology was squamous cell carcinoma (50%). Patients' mean age was 45.66 years (33 to 74 yr). The mean follow-up period was 35.2 months (30 to 49 months). During follow-up, no infection or foreign body reaction was encountered. Extrusion of titanium mesh occurred in 4 patients who underwent postoperative radiotherapy. Two cases of mild diplopia at extreme gaze occurred early during the postoperative period that resolved after a few months. Placing fascia lata between the titanium mesh surface of the orbital implant and the orbital contents was successful in preventing long-term diplopia or dystopia. Nevertheless, exposure of the titanium implant through the skin surface represented a complication of this technique in 25% of patients. Further studies are required with head-to-head comparisons of artificial materials and free flaps for reconstruction of maxillectomy defects. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

A new anisotropic mesh adaptation method based upon hierarchical a posteriori error estimates

Science.gov (United States)

Huang, Weizhang; Kamenski, Lennard; Lang, Jens

2010-03-01

A new anisotropic mesh adaptation strategy for finite element solution of elliptic differential equations is presented. It generates anisotropic adaptive meshes as quasi-uniform ones in some metric space, with the metric tensor being computed based on hierarchical a posteriori error estimates. A global hierarchical error estimate is employed in this study to obtain reliable directional information of the solution. Instead of solving the global error problem exactly, which is costly in general, we solve it iteratively using the symmetric Gauß-Seidel method. Numerical results show that a few GS iterations are sufficient for obtaining a reasonably good approximation to the error for use in anisotropic mesh adaptation. The new method is compared with several strategies using local error estimators or recovered Hessians. Numerical results are presented for a selection of test examples and a mathematical model for heat conduction in a thermal battery with large orthotropic jumps in the material coefficients.

Predicting mesh density for adaptive modelling of the global atmosphere.

Science.gov (United States)

Weller, Hilary

2009-11-28

The shallow water equations are solved using a mesh of polygons on the sphere, which adapts infrequently to the predicted future solution. Infrequent mesh adaptation reduces the cost of adaptation and load-balancing and will thus allow for more accurate mapping on adaptation. We simulate the growth of a barotropically unstable jet adapting the mesh every 12 h. Using an adaptation criterion based largely on the gradient of the vorticity leads to a mesh with around 20 per cent of the cells of a uniform mesh that gives equivalent results. This is a similar proportion to previous studies of the same test case with mesh adaptation every 1-20 min. The prediction of the mesh density involves solving the shallow water equations on a coarse mesh in advance of the locally refined mesh in order to estimate where features requiring higher resolution will grow, decay or move to. The adaptation criterion consists of two parts: that resolved on the coarse mesh, and that which is not resolved and so is passively advected on the coarse mesh. This combination leads to a balance between resolving features controlled by the large-scale dynamics and maintaining fine-scale features.

Mesh Adaptation and Shape Optimization on Unstructured Meshes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this SBIR CRM proposes to implement the entropy adjoint method for solution adaptive mesh refinement into the Loci/CHEM unstructured flow solver. The scheme will...

Mesh networks: an optimum solution for AMR

Energy Technology Data Exchange (ETDEWEB)

Mimno, G.

2003-12-01

Characteristics of mesh networks and the advantage of using them in automatic meter reading equipment (AMR) are discussed. Mesh networks are defined as being similar to a fishing net made of knots and links. In mesh networks the knots represent meter sites and the links are the radio paths between the meter sites and the neighbourhood concentrator. In mesh networks any knot in the communications chain can link to any other and the optimum path is calculated by the network by hopping from meter to meter until the radio message reaches a concentrator. This mesh communications architecture is said to be vastly superior to many older types of radio-based meter reading technologies; its main advantage is that it not only significantly improves the economics of fixed network deployment, but also supports time-of-use metering, remote disconnect services and advanced features, such as real-time pricing, demand response, and other efficiency measures, providing a better return on investment and reliability.

Shape space exploration of constrained meshes

KAUST Repository

Yang, Yongliang; Yang, Yijun; Pottmann, Helmut; Mitra, Niloy J.

2011-01-01

We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc. © 2011 ACM.

Shape space exploration of constrained meshes

KAUST Repository

Yang, Yongliang

2011-12-12

We present a general computational framework to locally characterize any shape space of meshes implicitly prescribed by a collection of non-linear constraints. We computationally access such manifolds, typically of high dimension and co-dimension, through first and second order approximants, namely tangent spaces and quadratically parameterized osculant surfaces. Exploration and navigation of desirable subspaces of the shape space with regard to application specific quality measures are enabled using approximants that are intrinsic to the underlying manifold and directly computable in the parameter space of the osculant surface. We demonstrate our framework on shape spaces of planar quad (PQ) meshes, where each mesh face is constrained to be (nearly) planar, and circular meshes, where each face has a circumcircle. We evaluate our framework for navigation and design exploration on a variety of inputs, while keeping context specific properties such as fairness, proximity to a reference surface, etc. © 2011 ACM.

A general coarse and fine mesh solution scheme for fluid flow modeling in VHTRS

International Nuclear Information System (INIS)

Clifford, I; Ivanov, K; Avramova, M.

2011-01-01

Coarse mesh Computational Fluid Dynamics (CFD) methods offer several advantages over traditional coarse mesh methods for the safety analysis of helium-cooled graphite-moderated Very High Temperature Reactors (VHTRs). This relatively new approach opens up the possibility for system-wide calculations to be carried out using a consistent set of field equations throughout the calculation, and subsequently the possibility for hybrid coarse/fine mesh or hierarchical multi scale CFD simulations. To date, a consistent methodology for hierarchical multi-scale CFD has not been developed. This paper describes work carried out in the initial development of a multi scale CFD solver intended to be used for the safety analysis of VHTRs. The VHTR is considered on any scale to consist of a homogenized two-phase mixture of fluid and stationary solid material of varying void fraction. A consistent set of conservation equations was selected such that they reduce to the single-phase conservation equations for the case where void fraction is unity. The discretization of the conservation equations uses a new pressure interpolation scheme capable of capturing the discontinuity in pressure across relatively large changes in void fraction. Based on this, a test solver was developed which supports fully unstructured meshes for three-dimensional time-dependent compressible flow problems, including buoyancy effects. For typical VHTR flow phenomena the new solver shows promise as an effective candidate for predicting the flow behavior on multiple scales, as it is capable of modeling both fine mesh single phase flows as well as coarse mesh flows in homogenized regions containing both fluid and solid materials. (author)

ROLE OF MESH REPAIR IN PELVIC ORGAN PROLAPSE, WITH PARTICULAR REFERENCE TO VAULT PROLAPSE & NULLIPAROUS PROLAPSE

Directory of Open Access Journals (Sweden)

Geeta Vandana Reddi

2017-12-01

Full Text Available BACKGROUND Pelvic organ prolapse is a common complaint in gynaecological practice. Nulliparous prolapse is seen in 2% of female population and vault prolapse in 0.5% following hysterectomy. Various surgical procedures have been described for the repair of vault prolapse e.g. transvaginal sacrospinous colpopexy, transabdominal sacral colpopexy, Le Forte's operation, colpoclesis, posterior intravaginal sling plasty etc. The introduction of synthetic mesh like Prolene, Mersilene for the repair of vault prolapse have the advantage of tensile strength. In nulliparous prolapse and uterovaginal prolapse also, the supports of uterus are weakened, so there seems to be a definite advantage of mesh repair over sling surgeries. MATERIALS AND METHODS A prospective study done in 50 patients with vault prolapse, Nulliparous prolapse and patients with UV prolapse who want to retain their menstrual and reproductive function were identified and repair of defects were done. 2 cases who underwent both hysterectomy and sacral colpopexy in two sittings were included in the study. They were followed up for a period of 6 weeks - 29 months. RESULTS In the present study, the mean age for vault prolapse was 52.14 years, mean parity was 3.36. Vault prolapses were found to be more common after abdominal hysterectomy 60.97% compared to vaginal 39.02%. Common indication for hysterectomy is pelvic organ prolapse followed by DUB in this study. The mean time between the hysterectomy and vault prolapse in this study was 5.46 years. Importance should be given to proper enterocoele repair and vault suspense time of primary surgery. In this study incidence of smoking in vault prolapse cases was 34.14% significant. In cases of sacral colpopexy for vault prolapse in this study there were no major mesh related complications and the cure rate was 97.5%. So, sacral colpopexy with prolene mesh i.e. abdominal mesh repair can be employed as the primary surgery for vault prolapse. The safety

Wireless mesh networks.

Science.gov (United States)

Wang, Xinheng

2008-01-01

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

Expansion of the role of web-based social networks related to synthetic mesh/tape complications.

Science.gov (United States)

Stephens, Caroline; Zimmern, Philippe E

2015-07-01

To update a prior report on web-based networks and frequently visited forums used by patients affected by synthetic mesh and/or tape (SMT) complications and to present the new developments in this dynamic SMT field following recent FDA notifications. A review of available blogs and forums on SMT complications was conducted using the terms "mesh complications", "mesh blogs", and "polypropylene mesh removal" in Internet search engines for the United States and several other countries. Forums from a prior report were analyzed for updates, and new forums with their founders were identified using same search methodology. The number of posts and new fields from 07/2011 to 10/2013 was recorded, and then divided into categories based on broad content (personal stories, supportive replies to complaints, patients recommending physicians, legal stories, newspaper/article stories with reactions, other). Although four social networks became inactive, four expanded and at least five new major ones surfaced. While personal stories and support remained a prominent topic of discussion, other categories increased, such as the number of posts discussing physician referrals and reactions to news stories. Additionally, the number of posts designated to personal stories decreased. Finally, discussion about the topic expanded internationally. Web-based social networks for women suffering from SMT have expanded and the contents have broadened with new domains being introduced. Patient networking remains a dynamic force in the current debate on the future of these procedures.

21 CFR 870.3650 - Pacemaker polymeric mesh bag.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker polymeric mesh bag. 870.3650 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3650 Pacemaker polymeric mesh bag. (a) Identification. A pacemaker polymeric mesh bag is an implanted device used to hold a...

Energy mesh optimization for multi-level calculation schemes

International Nuclear Information System (INIS)

Mosca, P.; Taofiki, A.; Bellier, P.; Prevost, A.

2011-01-01

The industrial calculations of third generation nuclear reactors are based on sophisticated strategies of homogenization and collapsing at different spatial and energetic levels. An important issue to ensure the quality of these calculation models is the choice of the collapsing energy mesh. In this work, we show a new approach to generate optimized energy meshes starting from the SHEM 281-group library. The optimization model is applied on 1D cylindrical cells and consists of finding an energy mesh which minimizes the errors between two successive collision probability calculations. The former is realized over the fine SHEM mesh with Livolant-Jeanpierre self-shielded cross sections and the latter is performed with collapsed cross sections over the energy mesh being optimized. The optimization is done by the particle swarm algorithm implemented in the code AEMC and multigroup flux solutions are obtained from standard APOLLO2 solvers. By this new approach, a set of new optimized meshes which encompass from 10 to 50 groups has been defined for PWR and BWR calculations. This set will allow users to adapt the energy detail of the solution to the complexity of the calculation (assembly, multi-assembly, two-dimensional whole core). Some preliminary verifications, in which the accuracy of the new meshes is measured compared to a direct 281-group calculation, show that the 30-group optimized mesh offers a good compromise between simulation time and accuracy for a standard 17 x 17 UO 2 assembly with and without control rods. (author)

QMESH RENUM QPLOT, Mesh Generator on 2-D Bodies for Finite Element Method Analysis, with Plot Utility

International Nuclear Information System (INIS)

Jones, R.E.; Schkade, A.F.; Eyberger, L.R.

1991-01-01

1 - Description of problem or function: A set of five programs which make up a self-organising mesh generation package. QMESH generates meshes having quadrilateral elements on arbitrarily-shaped, two-dimensional (planar or axisymmetric) bodies. It is designed for use with two-dimensional finite element analysis applications. A flexible hierarchical input scheme is used to describe bodies to QMESH as collections of regions. A mesh for each region is developed independently, with the final assembly and bandwidth minimization performed by the independent program, RENUM or RENUM8. RENUM is applied when four-node elements are desired. Eight-node elements (with mid-side nodes) may be obtained with RENUM8., QPLOT and QPLOT8 are plot programs for meshes generated by the QMESH/RENUM and QMESH/RENUM8 program pairs, respectively. QPLOT and QPLOT8 automatically section the mesh into appropriately-sized sections for legible display of node and element numbers. An overall plot showing the position of the selected plot areas is produced. 2 - Method of solution: The mesh generating process for each individual region begins with the installation of an initial mesh which is a transformation of a regular grid on the unit square. The dimensions and orientation of the initial mesh may be defined by the user or, optionally, may be chosen by QMESH. Various smoothing algorithms may be applied to the initial mesh. Then, the mesh may be 'restructured' using an iterative scheme involving 'element pair restructuring', 'acute element deletion', and smoothing. In element pair restructuring, the interface side between two elements is removed and placed between two different nodes belonging to the pair of elements, provided that the change produces an overall improvement in the shapes of the two elements. In acute element deletion, an element having one diagonal much shorter than the other is deleted by collapsing the short diagonal to zero length The exact order in which restructuring, element

Reconfigurable lattice mesh designs for programmable photonic processors.

Science.gov (United States)

Pérez, Daniel; Gasulla, Ivana; Capmany, José; Soref, Richard A

2016-05-30

We propose and analyse two novel mesh design geometries for the implementation of tunable optical cores in programmable photonic processors. These geometries are the hexagonal and the triangular lattice. They are compared here to a previously proposed square mesh topology in terms of a series of figures of merit that account for metrics that are relevant to on-chip integration of the mesh. We find that that the hexagonal mesh is the most suitable option of the three considered for the implementation of the reconfigurable optical core in the programmable processor.

Postoperative infection of an abdominal mesh due to methicillin resistant Staphylococcus Aureus - A case report

Directory of Open Access Journals (Sweden)

Ashok R

2004-01-01

Full Text Available Methicillin resistant Stephylococcus aureus (MRSA infection has now become a major problem in hospitals. We present a case of postoperative infection MRSA where the primary source of the infection was found to be an abdominal mesh that was used to reinforce the abdominal wall. After one year of surgery, the patient developed wound dehiscence and discharge. MRSA was isolated from the wound, mesh, external nares, throat and axilla. Initially she was started on clindamycin and discharged from the hospital. After 5 months, patient came back to the hospital with infection at the same site. The patient was then treated with vancomycin and MRSA clearance. She responded to the treatment with complete healing of the wound and clearance of MRSA.

Volume Decomposition and Feature Recognition for Hexahedral Mesh Generation

Energy Technology Data Exchange (ETDEWEB)

GADH,RAJIT; LU,YONG; TAUTGES,TIMOTHY J.

1999-09-27

Considerable progress has been made on automatic hexahedral mesh generation in recent years. Several automatic meshing algorithms have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on more general geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithm the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into meshable volumes. There are four phases in this approach: (1) Feature Determination to extinct decomposition features, (2) Cutting Surfaces Generation to form the ''tailored'' cutting surfaces, (3) Body Decomposition to get the imprinted volumes; and (4) Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Results are demonstrated over several parts with complicated topology and geometry.

A Reconfigurable Mesh-Ring Topology for Bluetooth Sensor Networks

Directory of Open Access Journals (Sweden)

Ben-Yi Wang

2018-05-01

Full Text Available In this paper, a Reconfigurable Mesh-Ring (RMR algorithm is proposed for Bluetooth sensor networks. The algorithm is designed in three stages to determine the optimal configuration of the mesh-ring network. Firstly, a designated root advertises and discovers its neighboring nodes. Secondly, a scatternet criterion is built to compute the minimum number of piconets and distributes the connection information for piconet and scatternet. Finally, a peak-search method is designed to determine the optimal mesh-ring configuration for various sizes of networks. To maximize the network capacity, the research problem is formulated by determining the best connectivity of available mesh links. During the formation and maintenance phases, three possible configurations (including piconet, scatternet, and hybrid are examined to determine the optimal placement of mesh links. The peak-search method is a systematic approach, and is implemented by three functional blocks: the topology formation block generates the mesh-ring topology, the routing efficiency block computes the routing performance, and the optimum decision block introduces a decision-making criterion to determine the optimum number of mesh links. Simulation results demonstrate that the optimal mesh-ring configuration can be determined and that the scatternet case achieves better overall performance than the other two configurations. The RMR topology also outperforms the conventional ring-based and cluster-based mesh methods in terms of throughput performance for Bluetooth configurable networks.

Coarse-mesh rebalancing acceleration for eigenvalue problems

International Nuclear Information System (INIS)

Asaoka, T.; Nakahara, Y.; Miyasaka, S.

1974-01-01

The coarse-mesh rebalance method is adopted for Monte Carlo schemes for aiming at accelerating the convergence of a source iteration process. At every completion of the Monte Carlo game for one batch of neutron histories, the scaling factor for the neutron flux is calculated to achieve the neutron balance in each coarse-mesh zone into which the total system is divided. This rebalance factor is multiplied to the weight of each fission source neutron in the coarse-mesh zone for playing the next Monte Carlo game. The numerical examples have shown that the coarse-mesh rebalance Monte Carlo calculation gives a good estimate of the eigenvalue already after several batches with a negligible extra computer time compared to the standard Monte Carlo. 5 references. (U.S.)

LR: Compact connectivity representation for triangle meshes

Energy Technology Data Exchange (ETDEWEB)

Gurung, T; Luffel, M; Lindstrom, P; Rossignac, J

2011-01-28

We propose LR (Laced Ring) - a simple data structure for representing the connectivity of manifold triangle meshes. LR provides the option to store on average either 1.08 references per triangle or 26.2 bits per triangle. Its construction, from an input mesh that supports constant-time adjacency queries, has linear space and time complexity, and involves ordering most vertices along a nearly-Hamiltonian cycle. LR is best suited for applications that process meshes with fixed connectivity, as any changes to the connectivity require the data structure to be rebuilt. We provide an implementation of the set of standard random-access, constant-time operators for traversing a mesh, and show that LR often saves both space and traversal time over competing representations.

Repair of an inguinoscrotal hernia in a patient with Becker muscular dystrophy.

Science.gov (United States)

Tatulli, F; Caraglia, A; Delcuratolo, A; Cassano, S; Chetta, G S

2017-01-01

Inguinal hernia repairs are routinely performed as outpatient procedures in most patients, whereas a few require admission due to clinical or social peculiarities. Muscular dystrophies are inherited disorders characterized by progressive muscle wasting and weakness. In case of surgery there is no definite recommendation for either general or regional anesthesia. This contribution regards a 48 y. o. male patient diagnosed with Becker Muscular Dystrophy by muscle biopsy 10 years earlier. He had a left-sided sizable inguinoscrotal hernia with repeat episodes of incarceration. An elective mesh repair with suction drainage was accomplished under selective spinal anesthesia. The post-operative course was uneventful. A few inguinal hernia repairs require admission due to peculiarities such as extensive scrotal hernias requiring suction drainage. Muscular dystrophies are inherited disorders with no cure and no two dystrophy patients are exactly alike, therefore the health issues will be different for each individual. In case of surgery there is no definite recommendation for either general or regional anesthesia. This contribution regards the successful elective mesh repair with suction drainage of a large left-sided inguino-scrotal hernia in a 48 y. o. male patient affected by Becker muscular dystrophy by selective spinal anesthesia obtained by 10 milligrams of hyperbaric bupivacaine. Effective mesh repair with suction drainage of large inguinal hernias under spinal anesthesia can be achieved in patients affected by muscular dystrophy.

HypGrid2D. A 2-d mesh generator

Energy Technology Data Exchange (ETDEWEB)

Soerensen, N N

1998-03-01

The implementation of a hyperbolic mesh generation procedure, based on an equation for orthogonality and an equation for the cell face area is described. The method is fast, robust and gives meshes with good smoothness and orthogonality. The procedure is implemented in a program called HypGrid2D. The HypGrid2D program is capable of generating C-, O- and `H`-meshes for use in connection with the EllipSys2D Navier-Stokes solver. To illustrate the capabilities of the program, some test examples are shown. First a series of C-meshes are generated around a NACA-0012 airfoil. Secondly a series of O-meshes are generated around a NACA-65-418 airfoil. Finally `H`-meshes are generated over a Gaussian hill and a linear escarpment. (au)

Adaptive mesh refinement for shocks and material interfaces

Energy Technology Data Exchange (ETDEWEB)

Dai, William Wenlong [Los Alamos National Laboratory

2010-01-01

There are three kinds of adaptive mesh refinement (AMR) in structured meshes. Block-based AMR sometimes over refines meshes. Cell-based AMR treats cells cell by cell and thus loses the advantage of the nature of structured meshes. Patch-based AMR is intended to combine advantages of block- and cell-based AMR, i.e., the nature of structured meshes and sharp regions of refinement. But, patch-based AMR has its own difficulties. For example, patch-based AMR typically cannot preserve symmetries of physics problems. In this paper, we will present an approach for a patch-based AMR for hydrodynamics simulations. The approach consists of clustering, symmetry preserving, mesh continuity, flux correction, communications, management of patches, and load balance. The special features of this patch-based AMR include symmetry preserving, efficiency of refinement across shock fronts and material interfaces, special implementation of flux correction, and patch management in parallel computing environments. To demonstrate the capability of the AMR framework, we will show both two- and three-dimensional hydrodynamics simulations with many levels of refinement.

Connectivity editing for quad-dominant meshes

KAUST Repository

Peng, Chihan

2013-08-01

We propose a connectivity editing framework for quad-dominant meshes. In our framework, the user can edit the mesh connectivity to control the location, type, and number of irregular vertices (with more or fewer than four neighbors) and irregular faces (non-quads). We provide a theoretical analysis of the problem, discuss what edits are possible and impossible, and describe how to implement an editing framework that realizes all possible editing operations. In the results, we show example edits and illustrate the advantages and disadvantages of different strategies for quad-dominant mesh design. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and John Wiley & Sons Ltd.

High-fidelity meshes from tissue samples for diffusion MRI simulations.

Science.gov (United States)

Panagiotaki, Eleftheria; Hall, Matt G; Zhang, Hui; Siow, Bernard; Lythgoe, Mark F; Alexander, Daniel C

2010-01-01

This paper presents a method for constructing detailed geometric models of tissue microstructure for synthesizing realistic diffusion MRI data. We construct three-dimensional mesh models from confocal microscopy image stacks using the marching cubes algorithm. Random-walk simulations within the resulting meshes provide synthetic diffusion MRI measurements. Experiments optimise simulation parameters and complexity of the meshes to achieve accuracy and reproducibility while minimizing computation time. Finally we assess the quality of the synthesized data from the mesh models by comparison with scanner data as well as synthetic data from simple geometric models and simplified meshes that vary only in two dimensions. The results support the extra complexity of the three-dimensional mesh compared to simpler models although sensitivity to the mesh resolution is quite robust.

Sexual function in women following transvaginal mesh procedures for the treatment of pelvic organ prolapse.

Science.gov (United States)

Liang, Ching-Chung; Lo, Tsia-Shu; Tseng, Ling-Hong; Lin, Yi-Hao; Lin, Yu-Jr; Chang, Shuenn-Dhy

2012-10-01

Synthetic mesh kits recently adopted in pelvic reconstructive surgeries have achieved great surgical efficacy, but the effects of transvaginal synthetic mesh procedures on women's sexual function are still controversial. This study was conducted to demonstrate sexual function in women before and after surgery with transvaginal mesh (TVM) repair for pelvic organ prolapse (POP). A total of 93 sexually active women scheduled for correcting POP with synthetic mesh kits were recruited. In addition to urogynecological history, pelvic examination by the Pelvic Organ Prolapse Quantification system, and urodynamic testing, consenting participants were asked to complete the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12) to evaluate sexual function before and after surgery. At the 3-month urodynamic studies, among the 25 patients with coexistent urodynamic stress incontinence (USI) who had undergone a concomitant transobturator suburethral tape procedure (TOT), 1 (4 %) had persistent USI; 8 of 68 (11.8 %) patients with a negative pessary test developed postoperative USI. Six-month prolapse recurrence rates following TVM alone and TVM with concomitant TOT were 9 and 12 %, respectively. The total PISQ-12 score after surgery showed worse results in the TVM alone group but not in the TVM with concomitant TOT group. The individual scores of PISQ-12 after surgery demonstrated prolapse-related items improved in both TVM groups; sexual function worsened in dyspareunia and behavior domains. Our data revealed that transvaginal synthetic mesh procedures for the treatment of POP generated favorable clinical outcomes, but situations might worsen in dyspareunia and behavior domains, thereby invoking a negative emotional reaction during intercourse after surgery.

Texturing of continuous LOD meshes with the hierarchical texture atlas

Science.gov (United States)

Birkholz, Hermann

2006-02-01

For the rendering of detailed virtual environments, trade-offs have to be made between image quality and rendering time. An immersive experience of virtual reality always demands high frame-rates with the best reachable image qual-ity. Continuous Level of Detail (cLoD) triangle-meshes provide an continuous spectrum of detail for a triangle mesh that can be used to create view-dependent approximations of the environment in real-time. This enables the rendering with a constant number of triangles and thus with constant frame-rates. Normally the construction of such cLoD mesh representations leads to the loss of all texture information of the original mesh. To overcome this problem, a parameter domain can be created, in order to map the surface properties (colour, texture, normal) to it. This parameter domain can be used to map the surface properties back to arbitrary approximations of the original mesh. The parameter domain is often a simplified version of the mesh to be parameterised. This limits the reachable simplification to the domain mesh which has to map the surface of the original mesh with the least possible stretch. In this paper, a hierarchical domain mesh is presented, that scales between very coarse domain meshes and good property-mapping.

MeSH: a window into full text for document summarization.

Science.gov (United States)

Bhattacharya, Sanmitra; Ha-Thuc, Viet; Srinivasan, Padmini

2011-07-01

Previous research in the biomedical text-mining domain has historically been limited to titles, abstracts and metadata available in MEDLINE records. Recent research initiatives such as TREC Genomics and BioCreAtIvE strongly point to the merits of moving beyond abstracts and into the realm of full texts. Full texts are, however, more expensive to process not only in terms of resources needed but also in terms of accuracy. Since full texts contain embellishments that elaborate, contextualize, contrast, supplement, etc., there is greater risk for false positives. Motivated by this, we explore an approach that offers a compromise between the extremes of abstracts and full texts. Specifically, we create reduced versions of full text documents that contain only important portions. In the long-term, our goal is to explore the use of such summaries for functions such as document retrieval and information extraction. Here, we focus on designing summarization strategies. In particular, we explore the use of MeSH terms, manually assigned to documents by trained annotators, as clues to select important text segments from the full text documents. Our experiments confirm the ability of our approach to pick the important text portions. Using the ROUGE measures for evaluation, we were able to achieve maximum ROUGE-1, ROUGE-2 and ROUGE-SU4 F-scores of 0.4150, 0.1435 and 0.1782, respectively, for our MeSH term-based method versus the maximum baseline scores of 0.3815, 0.1353 and 0.1428, respectively. Using a MeSH profile-based strategy, we were able to achieve maximum ROUGE F-scores of 0.4320, 0.1497 and 0.1887, respectively. Human evaluation of the baselines and our proposed strategies further corroborates the ability of our method to select important sentences from the full texts. sanmitra-bhattacharya@uiowa.edu; padmini-srinivasan@uiowa.edu.

Adaptive-mesh zoning by the equipotential method

Energy Technology Data Exchange (ETDEWEB)

Winslow, A.M.

1981-04-01

An adaptive mesh method is proposed for the numerical solution of differential equations which causes the mesh lines to move closer together in regions where higher resolution in some physical quantity T is desired. A coefficient D > 0 is introduced into the equipotential zoning equations, where D depends on the gradient of T . The equations are inverted, leading to nonlinear elliptic equations for the mesh coordinates with source terms which depend on the gradient of D. A functional form of D is proposed.

Fire performance of basalt FRP mesh reinforced HPC thin plates

DEFF Research Database (Denmark)

Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

2013-01-01

An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh...

Robust, multidimensional mesh motion based on Monge-Kantorovich equidistribution

Energy Technology Data Exchange (ETDEWEB)

Delzanno, G L [Los Alamos National Laboratory; Finn, J M [Los Alamos National Laboratory

2009-01-01

Mesh-motion (r-refinement) grid adaptivity schemes are attractive due to their potential to minimize the numerical error for a prescribed number of degrees of freedom. However, a key roadblock to a widespread deployment of the technique has been the formulation of robust, reliable mesh motion governing principles, which (1) guarantee a solution in multiple dimensions (2D and 3D), (2) avoid grid tangling (or folding of the mesh, whereby edges of a grid cell cross somewhere in the domain), and (3) can be solved effectively and efficiently. In this study, we formulate such a mesh-motion governing principle, based on volume equidistribution via Monge-Kantorovich optimization (MK). In earlier publications [1, 2], the advantages of this approach in regards to these points have been demonstrated for the time-independent case. In this study, demonstrate that Monge-Kantorovich equidistribution can in fact be used effectively in a time stepping context, and delivers an elegant solution to the otherwise pervasive problem of grid tangling in mesh motion approaches, without resorting to ad-hoc time-dependent terms (as in moving-mesh PDEs, or MMPDEs [3, 4]). We explore two distinct r-refinement implementations of MK: direct, where the current mesh relates to an initial, unchanging mesh, and sequential, where the current mesh is related to the previous one in time. We demonstrate that the direct approach is superior in regards to mesh distortion and robustness. The properties of the approach are illustrated with a paradigmatic hyperbolic PDE, the advection of a passive scalar. Imposed velocity flow fields or varying vorticity levels and flow shears are considered.

Current situation of transvaginal mesh repair for pelvic organ prolapse.

Science.gov (United States)

Zhu, Lan; Zhang, Lei

2014-09-01

Surgical mesh is a metallic or polymeric screen intended to be implanted to reinforce soft tissue or bone where weakness exists. Surgical mesh has been used since the 1950s to repair abdominal hernias. In the 1970s, gynecologists began using surgical mesh products to indicate the repair of pelvic organ prolapse (POP), and in the 1990s, gynecologists began using surgical mesh for POP. Then the U.S. Food and Drug Administration (FDA) approved the first surgical mesh product specifically for use in POP. Surgical mesh materials can be divided into several categories. Most surgical mesh devices cleared for POP procedures are composed of non-absorbable synthetic polypropylene. Mesh can be placed in the anterior vaginal wall to aid in the correction of cystocele (anterior repair), in the posterior vaginal wall to aid in correction of rectocele (posterior repair), or attached to the top of the vagina to correct uterine prolapse or vaginal apical prolapse (apical repair). Over the past decades, surgical mesh products for transvaginal POP repair became incorporated into "kits" that included tools to aid in the delivery and insertion of the mesh. Surgical mesh kits continue to evolve, adding new insertion tools, tissue fixation anchors, surgical techniques, and ab- sorbable and biological materials. This procedure has been performed popularly. It was also performed increased in China. But this new technique met some trouble recently and let shake in urogynecology.

Short-term complications associated with the use of transvaginal mesh in pelvic floor reconstructive surgery: Results from a multi-institutional prospectively maintained dataset.

Science.gov (United States)

Caveney, Maxx; Haddad, Devin; Matthews, Catherine; Badlani, Gopal; Mirzazadeh, Majid

2017-11-01

Vaginal reconstructive surgery can be performed with or without mesh. We sought to determine comparative rates of perioperative complications of native tissue versus vaginal mesh repairs for pelvic organ prolapse. Using the National Surgical Quality Improvement Program (NSQIP) database, we concatenated surgical data from vaginal procedures for prolapse repair, including anterior and posterior colporrhaphy, paravaginal defect repair, enterocele repair, and vaginal colpopexy using Current Procedural Terminology (CPT) coding. We stratified this data by the modifier associated with mesh usage at the time of the procedure. We then compared 30-day perioperative outcomes, postoperative complications (bleeding, infection, etc), and readmission rates between women with and without mesh-based repairs. We identified 10 657 vaginal reconstructive procedures without mesh and 959 mesh-based repairs from 2009 through 2013. Patients undergoing mesh repair were more likely to experience at least one complication than native tissue repair (9.28% vs 6.15%, P mesh group (11.37% vs 9.39%, P = 0.03). Procedures with mesh had a higher rate of perioperative bleeding requiring transfusion than native tissue repair (2.3% vs 0.49%, P surgical site infection (SSI) (0.52% vs 0.17%, P = 0.02). There were no significant differences in rates of readmission, superficial, or deep SSIs, pneumonia, urinary tract infection, sepsis, or renal failure. The use of vaginal mesh for pelvic organ prolapse repair appears to result in a higher rate of perioperative complications than native tissue repair. Patients undergoing these procedures should be counselled preoperatively concerning these risks. © 2017 Wiley Periodicals, Inc.

Using small meshed collecting bags on trawls to quantify trawls seabed disturbance of aquatic organisms

DEFF Research Database (Denmark)

Krag, Ludvig Ahm

impact on commercial fishing grounds. In this study we develop and test small-meshed collecting bags designed to retain juvenile fish and benthic megafauna. The collecting bags are mounted in the wings and body of the trawl. The catches in the collection bags provide information of the species and size...... in the mechanical effect, such as penetration depth of the ground gear of different trawl designs. Collecting bags are also mounted to the different sections of the trawl in pairs, one to collect the organisms that pass through the trawl meshes and one to collect the population. Standard selectivity analyses...

A Wrapping Method for Inserting Titanium Micro-Mesh Implants in the Reconstruction of Blowout Fractures

Directory of Open Access Journals (Sweden)

Tae Joon Choi

2016-01-01

Full Text Available Titanium micro-mesh implants are widely used in orbital wall reconstructions because they have several advantageous characteristics. However, the rough and irregular marginal spurs of the cut edges of the titanium mesh sheet impede the efficacious and minimally traumatic insertion of the implant, because these spurs may catch or hook the orbital soft tissue, skin, or conjunctiva during the insertion procedure. In order to prevent this problem, we developed an easy method of inserting a titanium micro-mesh, in which it is wrapped with the aseptic transparent plastic film that is used to pack surgical instruments or is attached to one side of the inner suture package. Fifty-four patients underwent orbital wall reconstruction using a transconjunctival or transcutaneous approach. The wrapped implant was easily inserted without catching or injuring the orbital soft tissue, skin, or conjunctiva. In most cases, the implant was inserted in one attempt. Postoperative computed tomographic scans showed excellent placement of the titanium micro-mesh and adequate anatomic reconstruction of the orbital walls. This wrapping insertion method may be useful for making the insertion of titanium micro-mesh implants in the reconstruction of orbital wall fractures easier and less traumatic.

Long-term quality-of-life outcome after mesh sacrocolpopexy for vaginal vault prolapse.

LENUS (Irish Health Repository)

Thomas, Arun Z

2009-12-01

To evaluate the long-term outcome of mesh sacrocolpopexy (MSC, which aims to restore normal pelvic floor anatomy to alleviate prolapse related symptoms) and its effect on patient\\'s quality of life, as women with vaginal vault prolapse commonly have various pelvic floor symptoms that can affect urinary, rectal and sexual function.

NeuroTessMesh: A Tool for the Generation and Visualization of Neuron Meshes and Adaptive On-the-Fly Refinement

Directory of Open Access Journals (Sweden)

Juan J. Garcia-Cantero

2017-06-01

Full Text Available Gaining a better understanding of the human brain continues to be one of the greatest challenges for science, largely because of the overwhelming complexity of the brain and the difficulty of analyzing the features and behavior of dense neural networks. Regarding analysis, 3D visualization has proven to be a useful tool for the evaluation of complex systems. However, the large number of neurons in non-trivial circuits, together with their intricate geometry, makes the visualization of a neuronal scenario an extremely challenging computational problem. Previous work in this area dealt with the generation of 3D polygonal meshes that approximated the cells’ overall anatomy but did not attempt to deal with the extremely high storage and computational cost required to manage a complex scene. This paper presents NeuroTessMesh, a tool specifically designed to cope with many of the problems associated with the visualization of neural circuits that are comprised of large numbers of cells. In addition, this method facilitates the recovery and visualization of the 3D geometry of cells included in databases, such as NeuroMorpho, and provides the tools needed to approximate missing information such as the soma’s morphology. This method takes as its only input the available compact, yet incomplete, morphological tracings of the cells as acquired by neuroscientists. It uses a multiresolution approach that combines an initial, coarse mesh generation with subsequent on-the-fly adaptive mesh refinement stages using tessellation shaders. For the coarse mesh generation, a novel approach, based on the Finite Element Method, allows approximation of the 3D shape of the soma from its incomplete description. Subsequently, the adaptive refinement process performed in the graphic card generates meshes that provide good visual quality geometries at a reasonable computational cost, both in terms of memory and rendering time. All the described techniques have been

Shear Alignment of Diblock Copolymers for Patterning Nanowire Meshes

Energy Technology Data Exchange (ETDEWEB)

Gustafson, Kyle T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-09-08

Metallic nanowire meshes are useful as cheap, flexible alternatives to indium tin oxide – an expensive, brittle material used in transparent conductive electrodes. We have fabricated nanowire meshes over areas up to 2.5 cm² by: 1) mechanically aligning parallel rows of diblock copolymer (diBCP) microdomains; 2) selectively infiltrating those domains with metallic ions; 3) etching away the diBCP template; 4) sintering to reduce ions to metal nanowires; and, 5) repeating steps 1 – 4 on the same sample at a 90° offset. We aligned parallel rows of polystyrene-b-poly(2-vinylpyridine) [PS(48.5 kDa)-b-P2VP(14.5 kDa)] microdomains by heating above its glass transition temperature (T_g ≈ 100°C), applying mechanical shear pressure (33 kPa) and normal force (13.7 N), and cooling below T_g. DiBCP samples were submerged in aqueous solutions of metallic ions (15 – 40 mM ions; 0.1 – 0.5 M HCl) for 30 – 90 minutes, which coordinate to nitrogen in P2VP. Subsequent ozone-etching and sintering steps yielded parallel nanowires. We aimed to optimize alignment parameters (e.g. shear and normal pressures, alignment duration, and PDMS thickness) to improve the quality, reproducibility, and scalability of meshes. We also investigated metals other than Pt and Au that may be patterned using this technique (Cu, Ag).

Resterilized Polypropylene Mesh for Inguinal Hernia Repair

African Journals Online (AJOL)

2018-04-19

Apr 19, 2018 ... Conclusion: The use of sterilized polypropylene mesh for the repair of inguinal ... and nonabsorbable materials to reduce the tissue–mesh. INTRODUCTION ... which we have been practicing in our center since we introduced ...

Evaluation of endoscopic laser excision of polypropylene mesh/sutures following anti-incontinence procedures.

LENUS (Irish Health Repository)

Davis, N F

2012-11-01

We reviewed our experience with and outcome of the largest series to our knowledge of patients who underwent endoscopic laser excision of eroded polypropylene mesh or sutures as a complication of previous anti-incontinence procedures.

Meshed-Pumpkin Super-Pressure Balloon Design

Science.gov (United States)

Jones, Jack; Yavrouian, Andre

2003-01-01

An improved, lightweight design has been proposed for super-pressure balloons used to carry scientific instruments at high altitudes in the atmosphere of Earth for times as long as 100 days. [A super-pressure balloon is one in which the pressure of the buoyant gas (typically, helium) is kept somewhat above ambient pressure in order to maintain approximately constant density and thereby regulate the altitude.] The proposed design, called "meshed pumpkin," incorporates the basic concept of the pumpkin design, which is so named because of its appearance. The pumpkin design entails less weight than does a spherical design, and the meshed-pumpkin design would reduce weight further. The basic idea of the meshed-pumpkin design is to reinforce the membrane of a pumpkin balloon by attaching a strong, lightweight fabric mesh to its outer surface. The reinforcement would make it possible to reduce the membrane mass to one-third or less of that of the basic pumpkin design while retaining sufficient strength to enable the balloon to remain at approximately constant altitude for months.

Anisotropic mesh adaptation for marine ice-sheet modelling

Science.gov (United States)

Gillet-Chaulet, Fabien; Tavard, Laure; Merino, Nacho; Peyaud, Vincent; Brondex, Julien; Durand, Gael; Gagliardini, Olivier

2017-04-01

Improving forecasts of ice-sheets contribution to sea-level rise requires, amongst others, to correctly model the dynamics of the grounding line (GL), i.e. the line where the ice detaches from its underlying bed and goes afloat on the ocean. Many numerical studies, including the intercomparison exercises MISMIP and MISMIP3D, have shown that grid refinement in the GL vicinity is a key component to obtain reliable results. Improving model accuracy while maintaining the computational cost affordable has then been an important target for the development of marine icesheet models. Adaptive mesh refinement (AMR) is a method where the accuracy of the solution is controlled by spatially adapting the mesh size. It has become popular in models using the finite element method as they naturally deal with unstructured meshes, but block-structured AMR has also been successfully applied to model GL dynamics. The main difficulty with AMR is to find efficient and reliable estimators of the numerical error to control the mesh size. Here, we use the estimator proposed by Frey and Alauzet (2015). Based on the interpolation error, it has been found effective in practice to control the numerical error, and has some flexibility, such as its ability to combine metrics for different variables, that makes it attractive. Routines to compute the anisotropic metric defining the mesh size have been implemented in the finite element ice flow model Elmer/Ice (Gagliardini et al., 2013). The mesh adaptation is performed using the freely available library MMG (Dapogny et al., 2014) called from Elmer/Ice. Using a setup based on the inter-comparison exercise MISMIP+ (Asay-Davis et al., 2016), we study the accuracy of the solution when the mesh is adapted using various variables (ice thickness, velocity, basal drag, …). We show that combining these variables allows to reduce the number of mesh nodes by more than one order of magnitude, for the same numerical accuracy, when compared to uniform mesh

Fault diagnosis for wind turbine planetary ring gear via a meshing resonance based filtering algorithm.

Science.gov (United States)

Wang, Tianyang; Chu, Fulei; Han, Qinkai

2017-03-01

Identifying the differences between the spectra or envelope spectra of a faulty signal and a healthy baseline signal is an efficient planetary gearbox local fault detection strategy. However, causes other than local faults can also generate the characteristic frequency of a ring gear fault; this may further affect the detection of a local fault. To address this issue, a new filtering algorithm based on the meshing resonance phenomenon is proposed. In detail, the raw signal is first decomposed into different frequency bands and levels. Then, a new meshing index and an MRgram are constructed to determine which bands belong to the meshing resonance frequency band. Furthermore, an optimal filter band is selected from this MRgram. Finally, the ring gear fault can be detected according to the envelope spectrum of the band-pass filtering result. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Multiphase flow of immiscible fluids on unstructured moving meshes

DEFF Research Database (Denmark)

Misztal, Marek Krzysztof; Erleben, Kenny; Bargteil, Adam

2012-01-01

In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization op...

Multiphase Flow of Immiscible Fluids on Unstructured Moving Meshes

DEFF Research Database (Denmark)

Misztal, Marek Krzysztof; Erleben, Kenny; Bargteil, Adam

2013-01-01

In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization op...

Laparoscopic removal of mesh used in pelvic floor surgery.

Science.gov (United States)

Khong, Su-Yen; Lam, Alan

2009-01-01

Various meshes are being used widely in clinical practice for pelvic reconstructive surgery despite the lack of evidence of their long-term safety and efficacy. Management of complications such as mesh erosion and dyspareunia can be challenging. Most mesh-related complications can probably be managed successfully via the transvaginal route; however, this may be impossible if surgical access is poor. This case report demonstrates the successful laparoscopic removal of mesh after several failed attempts via the vaginal route.

Shear strength of reinforced concrete beams strengthened by P.B.O. fiber mesh under loading

Directory of Open Access Journals (Sweden)

Blikharskyy Zinoviy

2017-01-01

Full Text Available This article presents experimental study of sheer strength of reinforced concrete beams without transverse steel reinforcement, which strengthened by composite materials. The feature of tests is that the beams’ strengthening is made under simultaneous action of loading. The research program involves a series of test beams with size 2100 × 200 × 100 mm and which contains control sample and three reinforced samples by reinforcing FRCM system. FRCM system consisting of two components: mineral mortar based on modified cement Ruredil X Mesh M750 and reinforcing P.B.O. fiber mesh Ruredil X Mesh Gold (Italy. The strength research of test samples was carried out with the shear distance to effective depth ratio a/d = 2. The strengthening loading levels were selected at 0.0, 0.3, 0.5 from shear strength of non strengthened control sample. As a result of experimental studies we found that during strengthening design the inclined cross section of beams we should take into account the existing level of loading. Using the strengthening system Ruredil X Mesh Gold the strengthening effect is reduced at 2.8 to 2.9 times while the existing level of loading increase from 0 to 50%.

GENERATION OF IRREGULAR HEXAGONAL MESHES

Directory of Open Access Journals (Sweden)

Vlasov Aleksandr Nikolaevich

2012-07-01

Decomposition is performed in a constructive way and, as option, it involves meshless representation. Further, this mapping method is used to generate the calculation mesh. In this paper, the authors analyze different cases of mapping onto simply connected and bi-connected canonical domains. They represent forward and backward mapping techniques. Their potential application for generation of nonuniform meshes within the framework of the asymptotic homogenization theory is also performed to assess and project effective characteristics of heterogeneous materials (composites.

Grid adaptation using chimera composite overlapping meshes

Science.gov (United States)

Kao, Kai-Hsiung; Liou, Meng-Sing; Chow, Chuen-Yen

1994-01-01

The objective of this paper is to perform grid adaptation using composite overlapping meshes in regions of large gradient to accurately capture the salient features during computation. The chimera grid scheme, a multiple overset mesh technique, is used in combination with a Navier-Stokes solver. The numerical solution is first converged to a steady state based on an initial coarse mesh. Solution-adaptive enhancement is then performed by using a secondary fine grid system which oversets on top of the base grid in the high-gradient region, but without requiring the mesh boundaries to join in any special way. Communications through boundary interfaces between those separated grids are carried out using trilinear interpolation. Application to the Euler equations for shock reflections and to shock wave/boundary layer interaction problem are tested. With the present method, the salient features are well-resolved.

THM-GTRF: New Spider meshes, New Hydra-TH runs

Energy Technology Data Exchange (ETDEWEB)

Bakosi, Jozsef [Los Alamos National Laboratory; Christon, Mark A. [Los Alamos National Laboratory; Francois, Marianne M. [Los Alamos National Laboratory; Lowrie, Robert B. [Los Alamos National Laboratory; Nourgaliev, Robert [Los Alamos National Laboratory

2012-06-20

Progress is reported on computational capabilities for the grid-to-rod-fretting (GTRF) problem of pressurized water reactors. Numeca's Hexpress/Hybrid mesh generator is demonstrated as an excellent alternative to generating computational meshes for complex flow geometries, such as in GTRF. Mesh assessment is carried out using standard industrial computational fluid dynamics practices. Hydra-TH, a simulation code developed at LANL for reactor thermal-hydraulics, is demonstrated on hybrid meshes, containing different element types. A series of new Hydra-TH calculations has been carried out collecting turbulence statistics. Preliminary results on the newly generated meshes are discussed; full analysis will be documented in the L3 milestone, THM.CFD.P5.05, Sept. 2012.

AUTOMATIC MESH GENERATION OF 3-D GEOMETRIC MODELS

Institute of Scientific and Technical Information of China (English)

刘剑飞

2003-01-01

In this paper the presentation of the ball-packing method is reviewed,and a scheme to generate mesh for complex 3-D geometric models is given,which consists of 4 steps:(1)create nodes in 3-D models by ball-packing method,(2)connect nodes to generate mesh by 3-D Delaunay triangulation,(3)retrieve the boundary of the model after Delaunay triangulation,(4)improve the mesh.

Water Penetration through a Superhydrophobic Mesh During a Drop Impact

Science.gov (United States)

Ryu, Seunggeol; Sen, Prosenjit; Nam, Youngsuk; Lee, Choongyeop

2017-01-01

When a water drop impacts a mesh having submillimeter pores, a part of the drop penetrates through the mesh if the impact velocity is sufficiently large. Here we show that different surface wettability, i.e., hydrophobicity and superhydrophobicity, leads to different water penetration dynamics on a mesh during drop impact. We show, despite the water repellence of a superhydrophobic surface, that water can penetrate a superhydrophobic mesh more easily (i.e., at a lower impact velocity) over a hydrophobic mesh via a penetration mechanism unique to a superhydrophobic mesh. On a superhydrophobic mesh, the water penetration can occur during the drop recoil stage, which appears at a lower impact velocity than the critical impact velocity for water penetration right upon impact. We propose that this unique water penetration on a superhydrophobic mesh can be attributed to the combination of the hydrodynamic focusing and the momentum transfer from the water drop when it is about to bounce off the surface, at which point the water drop retrieves most of its kinetic energy due to the negligible friction on superhydrophobic surfaces.

Engagement of Metal Debris into Gear Mesh

Science.gov (United States)

handschuh, Robert F.; Krantz, Timothy L.

2010-01-01

A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

A conceptual framework for technology-enabled and technology-dependent user behavior toward device mesh and mesh app

Directory of Open Access Journals (Sweden)

Ming-Hsiung Hsiao

2018-06-01

Full Text Available The device mesh and mesh app revealed by Gartner as the future strategic technology trend are able to predict people's need from their historic data, then provides the needed services or service innovation to support their activity engagement. However, many theories have identified that it is the motivation, rather than technology, that drives people to engage in activities or tasks. For this reason, this study builds a conceptual framework by integrating the extant logic and theories to explore how future technology would generate benefits for people. It integrates task-technology fit (TTF model and motivation theory (mainly expectancy-value theory to explain such technology user behavior. It also points out the difference between technology-enabled and technology-dependent user behavior and concludes that too much emphasis on the role of technology with too little attention on motivation would distort technology user behavior, and the role of technology as well. Keywords: Device mesh, Mesh app, Expectancy-value theory, Task-technology fit (TTF, Technology-enabled user, Technology-dependent user

LAPAROSCOPIC MANAGEMENT OF GIANT PARAESOPHAGEAL HERNIA WITH A SILICONE-COATED BIFACIAL MESH

Directory of Open Access Journals (Sweden)

S. Unguryanu

2016-01-01

Full Text Available BACKGROUND. Paraesophageal hernias are relatively uncommon. The incidence of this disease has increased recently, and esophageal hernias now account for 5–10% of all hiatus hernias. Surgical treatment is recommended for all patients with this disease because of high risk of complications: strangulation or perforation.CASE REPORT. A 44-year-old male patient with a giant and symptomatic paraesophageal hernia. The diagnosis was confirmed by instrumental examination. We performed laparoscopic repair using silicone-coated polypropylene bifacial mesh. The postoperative period was uneventful.CONCLUSION. The laparoscopic approach may be successfully used as a therapeutic option in the treatment for hiatal hernias. Our clinical experience showed, that the technique appeared to be valid and safe. In cases of large hiatal hernia with a defect greater than 5 cm, it is recommended to apply the mesh in order to minimize the recurrence rate.

A Survey of Solver-Related Geometry and Meshing Issues

Science.gov (United States)

Masters, James; Daniel, Derick; Gudenkauf, Jared; Hine, David; Sideroff, Chris

2016-01-01

There is a concern in the computational fluid dynamics community that mesh generation is a significant bottleneck in the CFD workflow. This is one of several papers that will help set the stage for a moderated panel discussion addressing this issue. Although certain general "rules of thumb" and a priori mesh metrics can be used to ensure that some base level of mesh quality is achieved, inadequate consideration is often given to the type of solver or particular flow regime on which the mesh will be utilized. This paper explores how an analyst may want to think differently about a mesh based on considerations such as if a flow is compressible vs. incompressible or hypersonic vs. subsonic or if the solver is node-centered vs. cell-centered. This paper is a high-level investigation intended to provide general insight into how considering the nature of the solver or flow when performing mesh generation has the potential to increase the accuracy and/or robustness of the solution and drive the mesh generation process to a state where it is no longer a hindrance to the analysis process.

Automated quadrilateral mesh generation for digital image structures

Institute of Scientific and Technical Information of China (English)

无

2011-01-01

With the development of advanced imaging technology, digital images are widely used. This paper proposes an automatic quadrilateral mesh generation algorithm for multi-colour imaged structures. It takes an original arbitrary digital image as an input for automatic quadrilateral mesh generation, this includes removing the noise, extracting and smoothing the boundary geometries between different colours, and automatic all-quad mesh generation with the above boundaries as constraints. An application example is...

Adaptive and dynamic meshing methods for numerical simulations

Science.gov (United States)

Acikgoz, Nazmiye

For the numerical simulation of many problems of engineering interest, it is desirable to have an automated mesh adaption tool capable of producing high quality meshes with an affordably low number of mesh points. This is important especially for problems, which are characterized by anisotropic features of the solution and require mesh clustering in the direction of high gradients. Another significant issue in meshing emerges in the area of unsteady simulations with moving boundaries or interfaces, where the motion of the boundary has to be accommodated by deforming the computational grid. Similarly, there exist problems where current mesh needs to be adapted to get more accurate solutions because either the high gradient regions are initially predicted inaccurately or they change location throughout the simulation. To solve these problems, we propose three novel procedures. For this purpose, in the first part of this work, we present an optimization procedure for three-dimensional anisotropic tetrahedral grids based on metric-driven h-adaptation. The desired anisotropy in the grid is dictated by a metric that defines the size, shape, and orientation of the grid elements throughout the computational domain. Through the use of topological and geometrical operators, the mesh is iteratively adapted until the final mesh minimizes a given objective function. In this work, the objective function measures the distance between the metric of each simplex and a target metric, which can be either user-defined (a-priori) or the result of a-posteriori error analysis. During the adaptation process, one tries to decrease the metric-based objective function until the final mesh is compliant with the target within a given tolerance. However, in regions such as corners and complex face intersections, the compliance condition was found to be very difficult or sometimes impossible to satisfy. In order to address this issue, we propose an optimization process based on an ad

A Rare Complication of Composite Dual Mesh: Migration and Enterocutaneous Fistula Formation

Directory of Open Access Journals (Sweden)

Ozgur Bostanci

2015-01-01

Full Text Available Introduction. Mesh is commonly employed for abdominal hernia repair because it ensures a low recurrence rate. However, enterocutaneous fistula due to mesh migration can occur as a very rare, late complication, for which diagnosis is very difficult. Presentation of Case. Here we report the case of an enterocutaneous fistula due to late mesh migration in a mentally retarded, diabetic, 35-year-old male after umbilical hernia repair with composite dual mesh in 2010. Discussion. Mesh is a foreign substance, because of that some of the complications including hematoma, seroma, foreign body reaction, organ damage, infection, mesh rejection, and fistula formation may occur after implantation of the mesh. In the literature, most cases of mesh-associated enterocutaneous fistula due to migration involved polypropylene meshes. Conclusion. This case serves as a reminder of migration of composite dual meshes.

Grid adaption using Chimera composite overlapping meshes

Science.gov (United States)

Kao, Kai-Hsiung; Liou, Meng-Sing; Chow, Chuen-Yen

1993-01-01

The objective of this paper is to perform grid adaptation using composite over-lapping meshes in regions of large gradient to capture the salient features accurately during computation. The Chimera grid scheme, a multiple overset mesh technique, is used in combination with a Navier-Stokes solver. The numerical solution is first converged to a steady state based on an initial coarse mesh. Solution-adaptive enhancement is then performed by using a secondary fine grid system which oversets on top of the base grid in the high-gradient region, but without requiring the mesh boundaries to join in any special way. Communications through boundary interfaces between those separated grids are carried out using tri-linear interpolation. Applications to the Euler equations for shock reflections and to a shock wave/boundary layer interaction problem are tested. With the present method, the salient features are well resolved.

The Analysis of the Usefulness of Welded Meshes to Embankment Reinforcement

Directory of Open Access Journals (Sweden)

Ćwirko Marcin

2017-09-01

Full Text Available The aim of this paper was to find an answer to the question about the possibility of using steel welded mesh in building the retaining walls of gabion baskets. In light of the currently used gabion structure solutions, among which double-woven mesh is much more popular, the focus was put on the possibility of using welded mesh. A numerical analysis was conducted to examine the behavior of welded and woven mesh subjected to various loads and the results obtained for both types of mesh were directly compared. The maximal displacement in mesh nodes was admitted as the measurement of the system behavior (in the case of both undamaged and damaged mesh.

Parallel Adaptive Mesh Refinement for High-Order Finite-Volume Schemes in Computational Fluid Dynamics

Science.gov (United States)

Schwing, Alan Michael

For computational fluid dynamics, the governing equations are solved on a discretized domain of nodes, faces, and cells. The quality of the grid or mesh can be a driving source for error in the results. While refinement studies can help guide the creation of a mesh, grid quality is largely determined by user expertise and understanding of the flow physics. Adaptive mesh refinement is a technique for enriching the mesh during a simulation based on metrics for error, impact on important parameters, or location of important flow features. This can offload from the user some of the difficult and ambiguous decisions necessary when discretizing the domain. This work explores the implementation of adaptive mesh refinement in an implicit, unstructured, finite-volume solver. Consideration is made for applying modern computational techniques in the presence of hanging nodes and refined cells. The approach is developed to be independent of the flow solver in order to provide a path for augmenting existing codes. It is designed to be applicable for unsteady simulations and refinement and coarsening of the grid does not impact the conservatism of the underlying numerics. The effect on high-order numerical fluxes of fourth- and sixth-order are explored. Provided the criteria for refinement is appropriately selected, solutions obtained using adapted meshes have no additional error when compared to results obtained on traditional, unadapted meshes. In order to leverage large-scale computational resources common today, the methods are parallelized using MPI. Parallel performance is considered for several test problems in order to assess scalability of both adapted and unadapted grids. Dynamic repartitioning of the mesh during refinement is crucial for load balancing an evolving grid. Development of the methods outlined here depend on a dual-memory approach that is described in detail. Validation of the solver developed here against a number of motivating problems shows favorable

Parallel adaptation of general three-dimensional hybrid meshes

International Nuclear Information System (INIS)

Kavouklis, Christos; Kallinderis, Yannis

2010-01-01

A new parallel dynamic mesh adaptation and load balancing algorithm for general hybrid grids has been developed. The meshes considered in this work are composed of four kinds of elements; tetrahedra, prisms, hexahedra and pyramids, which poses a challenge to parallel mesh adaptation. Additional complexity imposed by the presence of multiple types of elements affects especially data migration, updates of local data structures and interpartition data structures. Efficient partition of hybrid meshes has been accomplished by transforming them to suitable graphs and using serial graph partitioning algorithms. Communication among processors is based on the faces of the interpartition boundary and the termination detection algorithm of Dijkstra is employed to ensure proper flagging of edges for refinement. An inexpensive dynamic load balancing strategy is introduced to redistribute work load among processors after adaptation. In particular, only the initial coarse mesh, with proper weighting, is balanced which yields savings in computation time and relatively simple implementation of mesh quality preservation rules, while facilitating coarsening of refined elements. Special algorithms are employed for (i) data migration and dynamic updates of the local data structures, (ii) determination of the resulting interpartition boundary and (iii) identification of the communication pattern of processors. Several representative applications are included to evaluate the method.

Enriching Triangle Mesh Animations with Physically Based Simulation.

Science.gov (United States)

Li, Yijing; Xu, Hongyi; Barbic, Jernej

2017-10-01

We present a system to combine arbitrary triangle mesh animations with physically based Finite Element Method (FEM) simulation, enabling control over the combination both in space and time. The input is a triangle mesh animation obtained using any method, such as keyframed animation, character rigging, 3D scanning, or geometric shape modeling. The input may be non-physical, crude or even incomplete. The user provides weights, specified using a minimal user interface, for how much physically based simulation should be allowed to modify the animation in any region of the model, and in time. Our system then computes a physically-based animation that is constrained to the input animation to the amount prescribed by these weights. This permits smoothly turning physics on and off over space and time, making it possible for the output to strictly follow the input, to evolve purely based on physically based simulation, and anything in between. Achieving such results requires a careful combination of several system components. We propose and analyze these components, including proper automatic creation of simulation meshes (even for non-manifold and self-colliding undeformed triangle meshes), converting triangle mesh animations into animations of the simulation mesh, and resolving collisions and self-collisions while following the input.

Finite element simulation of impact response of wire mesh screens

Directory of Open Access Journals (Sweden)

Wang Caizheng

2015-01-01

Full Text Available In this paper, the response of wire mesh screens to low velocity impact with blunt objects is investigated using finite element (FE simulation. The woven wire mesh is modelled with homogeneous shell elements with equivalent smeared mechanical properties. The mechanical behaviour of the woven wire mesh was determined experimentally with tensile tests on steel wire mesh coupons to generate the data for the smeared shell material used in the FE. The effects of impacts with a low mass (4 kg and a large mass (40 kg providing the same impact energy are studied. The joint between the wire mesh screen and the aluminium frame surrounding it is modelled using contact elements with friction between the corresponding elements. Damage to the screen of different types compromising its structural integrity, such as mesh separation and pulling out from the surrounding frame is modelled. The FE simulation is validated with results of impact tests conducted on woven steel wire screen meshes.

Finite element meshing approached as a global minimization process

Energy Technology Data Exchange (ETDEWEB)

WITKOWSKI,WALTER R.; JUNG,JOSEPH; DOHRMANN,CLARK R.; LEUNG,VITUS J.

2000-03-01

The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested

Interactive Shape Modeling using a Skeleton-Mesh Co-Representation

DEFF Research Database (Denmark)

Bærentzen, Jacob Andreas; Abdrashitov, Rinat; Singh, Karan

2014-01-01

We introduce the Polar-Annular Mesh representation (PAM). A PAM is a mesh-skeleton co-representation designed for the modeling of 3D organic, articulated shapes. A PAM represents a manifold mesh as a partition of polar (triangle fans) and annular (rings of quads) regions. The skeletal topology of...... a PAM to a quad-only mesh. We further present a PAM-based multi-touch sculpting application in order to demonstrate its utility as a shape representation for the interactive modeling of organic, articulated figures as well as for editing and posing of pre-existing models....

Transvaginal Mesh and Transanal Resection to Treat Outlet Obstruction Constipation Caused by Rectocele

OpenAIRE

Shi, Yang; Yu, Yongjun; Zhang, Xipeng; Li, Yuwei

2017-01-01

Background The aim of this study was to evaluate the curative effect of transvaginal mesh repair (TVMR) and stapled transanal rectal resection (STARR) in treating outlet obstruction constipation caused by rectocele. Material/Methods Patients who had outlet obstruction constipation caused by rectocele were retrospectively analyzed and 39 patients were enrolled the study. Patients were assigned to either the TVMR or STARR group. Postoperative factors such as complications, pain, recurrence rate...

ABOUT ESTIMATION OF THE OPTIMAL PARAMETERS OF MESH IN FISHING GEAR FOR FISHERY IN UKRAINE

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A. Chuklin

2013-06-01

Full Text Available The analysis of biometric exterior indicators of haarder (Liza haematocheilus in the Azov Sea is given and by example of use of these indicators the calculations for optimization of the parameters of mesh in fishing gear for fish catching in the Ukraine is complete. The calculations show that the minimum mesh size which provides selective catch capacity concerning haarder of commercial measure (more than 38 cm should be increased in size from 30 mm to 40 mm. In this case, the probability to continue catching of juveniles from 26.8 cm to 38 cm remains, but its share will be significantly less than in case of using adopted now mesh size of 30 mm. The proposed method is recommended for engineering and biological calculations for the design of new gear and improvement of commercial fishing regulations in order to optimize and improve the effectiveness of management of fish stocks.

Cartesian anisotropic mesh adaptation for compressible flow

International Nuclear Information System (INIS)

Keats, W.A.; Lien, F.-S.

2004-01-01

Simulating transient compressible flows involving shock waves presents challenges to the CFD practitioner in terms of the mesh quality required to resolve discontinuities and prevent smearing. This paper discusses a novel two-dimensional Cartesian anisotropic mesh adaptation technique implemented for compressible flow. This technique, developed for laminar flow by Ham, Lien and Strong, is efficient because it refines and coarsens cells using criteria that consider the solution in each of the cardinal directions separately. In this paper the method will be applied to compressible flow. The procedure shows promise in its ability to deliver good quality solutions while achieving computational savings. The convection scheme used is the Advective Upstream Splitting Method (Plus), and the refinement/ coarsening criteria are based on work done by Ham et al. Transient shock wave diffraction over a backward step and shock reflection over a forward step are considered as test cases because they demonstrate that the quality of the solution can be maintained as the mesh is refined and coarsened in time. The data structure is explained in relation to the computational mesh, and the object-oriented design and implementation of the code is presented. Refinement and coarsening algorithms are outlined. Computational savings over uniform and isotropic mesh approaches are shown to be significant. (author)

Prevention of parastomal hernias with 3D funnel meshes in intraperitoneal onlay position by placement during initial stoma formation.

Science.gov (United States)

Köhler, G; Hofmann, A; Lechner, M; Mayer, F; Wundsam, H; Emmanuel, K; Fortelny, R H

2016-02-01

In patients with terminal ostomies, parastomal hernias (PSHs) occur on a frequent basis. They are commonly associated with various degrees of complaints and occasionally lead to life-threatening complications. Various strategies and measures have been tested and evaluated, but to date there is a lack of published evidence with regard to the best surgical technique for the prevention of PSH development. We conducted a retrospective analysis of prospectively collected data of eighty patients, who underwent elective permanent ostomy formation between 2009 and 2014 by means of prophylactic implantation of a three-dimensional (3D) funnel mesh in intraperitoneal onlay (IPOM) position. PSH developed in three patients (3.75%). No mesh-related complications were encountered and none of the implants had to be removed. Ostomy-related complications had to be noted in seven (8.75%) cases. No manifestation of ostomy prolapse occurred. Follow-up time was a median 21 (range 3-47) months. The prophylactical implantation of a specially shaped, 3D mesh implant in IPOM technique during initial formation of a terminal enterostomy is safe, highly efficient and comparatively easy to perform. As opposed to what can be achieved with flat or keyhole meshes, the inner boundary areas of the ostomy itself can be well covered and protected from the surging viscera with the 3D implants. At the same time, the vertical, tunnel-shaped part of the mesh provides sufficient protection from an ostomy prolapse. Further studies will be needed to compare the efficacy of various known approaches to PSH prevention.

Moving mesh generation with a sequential approach for solving PDEs

DEFF Research Database (Denmark)

In moving mesh methods, physical PDEs and a mesh equation derived from equidistribution of an error metrics (so-called the monitor function) are simultaneously solved and meshes are dynamically concentrated on steep regions (Lim et al., 2001). However, the simultaneous solution procedure...... a simple and robust moving mesh algorithm in one or multidimension. In this study, we propose a sequential solution procedure including two separate parts: prediction step to obtain an approximate solution to a next time level (integration of physical PDEs) and regriding step at the next time level (mesh...... generation and solution interpolation). Convection terms, which appear in physical PDEs and a mesh equation, are discretized by a WENO (Weighted Essentially Non-Oscillatory) scheme under the consrvative form. This sequential approach is to keep the advantages of robustness and simplicity for the static...

The Role of Vaginal Mesh Procedures in Pelvic Organ Prolapse Surgery in View of Complication Risk

OpenAIRE

Ellington, David R.; Richter, Holly E.

2013-01-01

Synthetic transvaginal mesh has been employed in the treatment of pelvic organ prolapse for more than a decade. As the use of these devices increased during this period so did adverse event reporting. In 2008, the Food and Drug Administration (FDA) Public Health Notification informed physicians and patients of rising concerns with the use of synthetic transvaginal mesh. Shortly thereafter and in parallel to marked increases in adverse event reporting within the Manufacturer and User Device E...

Preliminary experience of titanium mesh cages for pathological fracture of middle and lower cervical vertebrae.

Science.gov (United States)

Chuang, Hao-Che; Wei, Sung-Tai; Lee, Han-Chung; Chen, Chun-Chung; Lee, Wen-Yuen; Cho, Der-Yang

2008-11-01

The advantages and disadvantages of titanium mesh cages (TMCs) assisted by anterior cervical plates (ACPs) for interbody fusion following cervical corpectomy were investigated. Between January 2002 and September 2006, 17 patients with cervical radiculomyelopathy caused by metastasis-induced pathologic fractures were selected for anterior corpectomy. TMCs were inserted into the post-corpectomy defect and stabilized by placement of ACPs filled with Triosite. Post-operative plain X-ray films indicated maintenance of spinal stability. No ceramic, donor site or surgery-related complications were observed. True trabeculation was observed in axial and reconstructive CT scans in all surviving patients one year after surgery. Neurological recovery, pain control, and good quality of life were achieved. Short hospital stays, minimal blood loss, short operation times and brief periods of bed confinement were also observed. We conclude that a TMC assisted by an ACP is safe and effective for interbody fusion following cervical corpectomy for pathological fractures resulting from cervical vertebral metastases.

Polyhedral meshing in numerical analysis of conjugate heat transfer

Science.gov (United States)

Sosnowski, Marcin; Krzywanski, Jaroslaw; Grabowska, Karolina; Gnatowska, Renata

2018-06-01

Computational methods have been widely applied in conjugate heat transfer analysis. The very first and crucial step in such research is the meshing process which consists in dividing the analysed geometry into numerous small control volumes (cells). In Computational Fluid Dynamics (CFD) applications it is desirable to use the hexahedral cells as the resulting mesh is characterized by low numerical diffusion. Unfortunately generating such mesh can be a very time-consuming task and in case of complicated geometry - it may not be possible to generate cells of good quality. Therefore tetrahedral cells have been implemented into commercial pre-processors. Their advantage is the ease of its generation even in case of very complex geometry. On the other hand tetrahedrons cannot be stretched excessively without decreasing the mesh quality factor, so significantly larger number of cells has to be used in comparison to hexahedral mesh in order to achieve a reasonable accuracy. Moreover the numerical diffusion of tetrahedral elements is significantly higher. Therefore the polyhedral cells are proposed within the paper in order to combine the advantages of hexahedrons (low numerical diffusion resulting in accurate solution) and tetrahedrons (rapid semi-automatic generation) as well as to overcome the disadvantages of both the above mentioned mesh types. The major benefit of polyhedral mesh is that each individual cell has many neighbours, so gradients can be well approximated. Polyhedrons are also less sensitive to stretching than tetrahedrons which results in better mesh quality leading to improved numerical stability of the model. In addition, numerical diffusion is reduced due to mass exchange over numerous faces. This leads to a more accurate solution achieved with a lower cell count. Therefore detailed comparison of numerical modelling results concerning conjugate heat transfer using tetrahedral and polyhedral meshes is presented in the paper.

r-Adaptive mesh generation for shell finite element analysis

International Nuclear Information System (INIS)

Cho, Maenghyo; Jun, Seongki

2004-01-01

An r-adaptive method or moving grid technique relocates a grid so that it becomes concentrated in the desired region. This concentration improves the accuracy and efficiency of finite element solutions. We apply the r-adaptive method to computational mesh of shell surfaces, which is initially regular and uniform. The r-adaptive method, given by Liao and Anderson [Appl. Anal. 44 (1992) 285], aggregate the grid in the region with a relatively high weight function without any grid-tangling. The stress error estimator is calculated in the initial uniform mesh for a weight function. However, since the r-adaptive method is a method that moves the grid, shell surface geometry error such as curvature error and mesh distortion error will increase. Therefore, to represent the exact geometry of a shell surface and to prevent surface geometric errors, we use the Naghdi's shell theory and express the shell surface by a B-spline patch. In addition, using a nine-node element, which is relatively less sensitive to mesh distortion, we try to diminish mesh distortion error in the application of an r-adaptive method. In the numerical examples, it is shown that the values of the error estimator for a cylinder, hemisphere, and torus in the overall domain can be reduced effectively by using the mesh generated by the r-adaptive method. Also, the reductions of the estimated relative errors are demonstrated in the numerical examples. In particular, a new functional is proposed to construct an adjusted mesh configuration by considering a mesh distortion measure as well as the stress error function. The proposed weight function provides a reliable mesh adaptation method after a parameter value in the weight function is properly chosen

Form-finding with polyhedral meshes made simple

KAUST Repository

Tang, Chengcheng

2014-07-27

We solve the form-finding problem for polyhedral meshes in a way which combines form, function and fabrication; taking care of user-specified constraints like boundary interpolation, planarity of faces, statics, panel size and shape, enclosed volume, and last, but not least, cost. Our main application is the interactive modeling of meshes for architectural and industrial design. Our approach can be described as guided exploration of the constraint space whose algebraic structure is simplified by introducing auxiliary variables and ensuring that constraints are at most quadratic. Computationally, we perform a projection onto the constraint space which is biased towards low values of an energy which expresses desirable "soft" properties like fairness. We have created a tool which elegantly handles difficult tasks, such as taking boundary-alignment of polyhedral meshes into account, planarization, fairing under planarity side conditions, handling hybrid meshes, and extending the treatment of static equilibrium to shapes which possess overhanging parts.

Form-finding with polyhedral meshes made simple

KAUST Repository

Tang, Chengcheng; Sun, Xiang; Gomes, Maria Alexandra; Wallner, Johannes; Pottmann, Helmut

2014-01-01

We solve the form-finding problem for polyhedral meshes in a way which combines form, function and fabrication; taking care of user-specified constraints like boundary interpolation, planarity of faces, statics, panel size and shape, enclosed volume, and last, but not least, cost. Our main application is the interactive modeling of meshes for architectural and industrial design. Our approach can be described as guided exploration of the constraint space whose algebraic structure is simplified by introducing auxiliary variables and ensuring that constraints are at most quadratic. Computationally, we perform a projection onto the constraint space which is biased towards low values of an energy which expresses desirable "soft" properties like fairness. We have created a tool which elegantly handles difficult tasks, such as taking boundary-alignment of polyhedral meshes into account, planarization, fairing under planarity side conditions, handling hybrid meshes, and extending the treatment of static equilibrium to shapes which possess overhanging parts.

A moving mesh method with variable relaxation time

OpenAIRE

Soheili, Ali Reza; Stockie, John M.

2006-01-01

We propose a moving mesh adaptive approach for solving time-dependent partial differential equations. The motion of spatial grid points is governed by a moving mesh PDE (MMPDE) in which a mesh relaxation time \\tau is employed as a regularization parameter. Previously reported results on MMPDEs have invariably employed a constant value of the parameter \\tau. We extend this standard approach by incorporating a variable relaxation time that is calculated adaptively alongside the solution in orde...

Mesh Inguinal Hernia Repair and Appendectomy in the Treatment of Amyand’s Hernia with Non-Inflamed Appendices

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Emin Kose

2017-01-01

Full Text Available Amyand’s hernia is defined as protrusion of the vermiform appendix in an inguinal hernia sac. It is a rare entity with variable clinical presentation from normal vermiform appendix to abscess formation due to perforation of acute appendicitis. Although surgical treatment includes appendectomy and hernia repair, appendectomy in the absence of an inflamed appendix and use of a mesh in cases of appendectomy remain to be controversial. The aim of this study was to review the experience of mesh inguinal hernia repair plus appendectomy performed for Amyand’s hernia with noninflamed appendices. There were five male patients with a mean age of 42.4 ± 16.1 years in this retrospective study in which Amyand’s hernia was treated with mesh inguinal hernia repair plus appendectomy for noninflamed appendices. Patients with acute appendicitis and perforated vermiform appendix were excluded. There were four right sided and one bilateral inguinal hernia. Postoperative courses were uneventful. During the follow-up period (14.0 ± 7.7 months, there was no inguinal hernia recurrence. Mesh inguinal hernia repair with appendectomy can be performed for Amyand’s hernia in the absence of acute appendicitis. However, presence of fibrous connections between the vermiform appendix and the surrounding hernia sac may be regarded as a parameter to perform appendectomy.

Introducing a distributed unstructured mesh into gyrokinetic particle-in-cell code, XGC

Science.gov (United States)

Yoon, Eisung; Shephard, Mark; Seol, E. Seegyoung; Kalyanaraman, Kaushik

2017-10-01

XGC has shown good scalability for large leadership supercomputers. The current production version uses a copy of the entire unstructured finite element mesh on every MPI rank. Although an obvious scalability issue if the mesh sizes are to be dramatically increased, the current approach is also not optimal with respect to data locality of particles and mesh information. To address these issues we have initiated the development of a distributed mesh PIC method. This approach directly addresses the base scalability issue with respect to mesh size and, through the use of a mesh entity centric view of the particle mesh relationship, provides opportunities to address data locality needs of many core and GPU supported heterogeneous systems. The parallel mesh PIC capabilities are being built on the Parallel Unstructured Mesh Infrastructure (PUMI). The presentation will first overview the form of mesh distribution used and indicate the structures and functions used to support the mesh, the particles and their interaction. Attention will then focus on the node-level optimizations being carried out to ensure performant operation of all PIC operations on the distributed mesh. Partnership for Edge Physics Simulation (EPSI) Grant No. DE-SC0008449 and Center for Extended Magnetohydrodynamic Modeling (CEMM) Grant No. DE-SC0006618.