Are PEEK-on-Ceramic Bearings an Option for Total Disc Arthroplasty? An In Vitro Tribology Study.

Science.gov (United States)

Siskey, Ryan; Ciccarelli, Lauren; Lui, Melissa K C; Kurtz, Steven M

2016-11-01

endplates were the primary sources of wear and demonstrated an abrasive wear mechanism. Under idealized and impingement conditions, the ceramic core also demonstrated slight polishing of the articulating surface but the change in mass was unmeasurable. During abrasive testing, the titanium transfer on the core was shown to polish over 5 MC of testing. In all cases and consistent with previous studies of other PEEK bearing couples, the particle size was primarily < 2 µm and morphology was smooth and spheroidal. Overall, the idealized PEEK-on-ceramic wear rate (0.7 ± 0.1 mm 3 /MC) appears comparable to the published wear rates for other polymer-on-hard bearing couples (0.3-6.7 mm 3 /MC) and within the range of 0.2 to 1.9 mm 3 /MC reported for PEEK-on-PEEK cervical disc designs. The particles, based on size and morphology, also suggest the wear mechanism is comparable between the PEEK-on-ceramic couple and other polymer-on-ceramic orthopaedic couples. The PEEK-on-ceramic bearing considered in this study is a novel bearing couple for use in total disc arthroplasty devices and will require clinical evaluation to fully assess the bearing couple and total disc design. However, the wear rates under idealized and adverse conditions, and particle size and morphology, suggest that PEEK-on-ceramic bearings may be a reasonable alternative to polyethylene-on-CoCr and metal-on-metal bearings currently used in cervical TDRs.

Acquired spondylolysis after implantation of a lumbar ProDisc II prosthesis: case report and review of the literature.

Science.gov (United States)

Schulte, Tobias L; Lerner, Thomas; Hackenberg, Lars; Liljenqvist, Ulf; Bullmann, Viola

2007-10-15

A case of acquired lumbar spondylolysis following lumbar disc arthroplasty L5-S1 in an 40-year-old woman and review of the literature. To present and discuss a case of acquired lumbar spondylolysis after implantation of an artificial disc L5-S1 that may have impaired a good clinical result requiring additional posterior lumbar instrumentation and fusion in order to improve understanding of this condition and to propose an effective method of surgical management. Lumbar disc arthroplasty is a possible surgical option for patients with degenerative disc disease. Acquired spondylolysis is a rare but known complication of spinal fusion but has never been described as a consequence of mobile disc arthroplasty. The authors present the first case in the literature who developed this complication. A 40-year-old woman with severe osteochondrosis L5-S1 and discogenic lumbar back pain underwent implantation of an artificial disc. Surgery and postoperative course were uneventful and the patient improved significantly as for back pain and mobility. Eighteen months after surgery, the patient was again admitted to our outpatient clinic for back pain that had slowly increased over time. The radiologic workup showed a new spondylolysis L5 without a spondylolisthesis. Because of unsuccessful conservative treatment, the patient underwent posterior lumbar instrumentation and fusion L5-S1, leading to a significant pain reduction and a good clinical outcome. Spine surgeons should be aware of the possibility of lumbar disc arthroplasty to induce acquired spondylolysis impairing good clinical results.

Fusion around cervical disc prosthesis: case report.

NARCIS (Netherlands)

Bartels, R.H.M.A.; Donk, R.

2005-01-01

OBJECTIVE AND IMPORTANCE: Cervical arthroplasty is a relatively new method to maintain motion after cervical anterior discectomy. Two cases are presented in which bony fusion occurred around a cervical disc prosthesis. CLINICAL PRESENTATION: A 30-year-old man and a 49-year-old woman underwent a

Radiological aspects of Arthroplasties

International Nuclear Information System (INIS)

Garcia, Sara Eugenia; Barragan, John Henry; Narvaez, Jorge Andres

2008-01-01

The development of new surgical techniques, of new prosthetic materials, and the increase in life expectancy with greater coverage of health services has ugmented the performance of hip replacements in our country. The radiologist should be familiar with the different surgical techniques and prosthetic devices, the evaluation of its components and associated complications. The most frequently performed arthroplasties are: shoulder, elbow, hip and knee replacement. This article reviews the most frequent prosthetic devices used, the radiological aspects of arthroplasties and their most common complications.

Finite element study of a lumbar intervertebral disc nucleus replacement device

Directory of Open Access Journals (Sweden)

Jessica S Coogan

2016-12-01

Full Text Available Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics

Focal hypermobility observed in cervical arthroplasty with Mobi-C.

Science.gov (United States)

Kerferd, Jack William; Abi-Hanna, David; Phan, Kevin; Rao, Prashanth; Mobbs, Ralph J

2017-12-01

In recent decades cervical arthroplasty, or cervical disc replacement, has been steadily increasing in popularity as a procedure for the treatment of degenerative pathologies of the cervical spine. This is based on an evolving body of literature that documents superior outcomes in cervical disc replacement over fusion, for both single and double level pathologies, in well selected patients. One of the more recent and popular implants currently on the market is the Mobi-C cervical artificial disc (LDR Medical; Troyes, France). In this paper we report on two cases where focal hypermobility was observed following total disc replacement using the Mobi-C cervical artificial disc. This is followed by a discussion as to potential contributing factors to this hypermobility in relation to both implant design, and operative technique, suggesting potential changes that might prevent this in future patients.

A custom-made guide-wire positioning device for Hip Surface Replacement Arthroplasty: description and first results

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Clijmans Tim

2010-07-01

Full Text Available Abstract Background Hip surface replacement arthroplasty (SRA can be an alternative for total hip arthroplasty. The short and long-term outcome of hip surface replacement arthroplasty mainly relies on the optimal size and position of the femoral component. This can be defined before surgery with pre-operative templating. Reproducing the optimal, templated femoral implant position during surgery relies on guide wire positioning devices in combination with visual inspection and experience of the surgeon. Another method of transferring the templated position into surgery is by navigation or Computer Assisted Surgery (CAS. Though CAS is documented to increase accurate placement particularly in case of normal hip anatomy, it requires bulky equipment that is not readily available in each centre. Methods A custom made neck jig device is presented as well as the results of a pilot study. The device is produced based on data pre-operatively acquired with CT-scan. The position of the guide wire is chosen as the anatomical axis of the femoral neck. Adjustments to the design of the jig are made based on the orthopedic surgeon's recommendations for the drill direction. The SRA jig is designed as a slightly more-than-hemispherical cage to fit the anterior part of the femoral head. The cage is connected to an anterior neck support. Four knifes are attached on the central arch of the cage. A drill guide cylinder is attached to the cage, thus allowing guide wire positioning as pre-operatively planned. Custom made devices were tested in 5 patients scheduled for total hip arthroplasty. The orthopedic surgeons reported the practical aspects of the use of the neck-jig device. The retrieved femoral heads were analyzed to assess the achieved drill place in mm deviation from the predefined location and orientation compared to the predefined orientation. Results The orthopedic surgeons rated the passive stability, full contact with neck portion of the jig and knife

Failure of cervical arthroplasty in a patient with adjacent segment disease associated with Klippel-Feil syndrome

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Ioannis D Papanastassiou

2011-01-01

Full Text Available Cervical arthroplasty may be justified in patients with Klippel-Feil syndrome (KFS in order to preserve cervical motion. The aim of this paper is to report an arthroplasty failure in a patient with KFS. A 36-year-old woman with KFS underwent two-level arthroplasty for adjacent segment disc degeneration. Anterior migration of the cranial prosthesis was encountered 5 months postoperatively and was successfully revised with anterior cervical fusion. Cervical arthroplasty in an extensively stiff and fused neck is challenging and may lead to catastrophic failure. Although motion preservation is desirable in KFS, the special biomechanical features may hinder arthroplasty. Fusion or hybrid constructs may represent more reasonable options, especially when multiple fused segments are present.

The change of adjacent segment after cervical disc arthroplasty compared with anterior cervical discectomy and fusion: a meta-analysis of randomized controlled trials.

Science.gov (United States)

Dong, Liang; Xu, Zhengwei; Chen, Xiujin; Wang, Dongqi; Li, Dichen; Liu, Tuanjing; Hao, Dingjun

2017-10-01

Many meta-analyses have been performed to study the efficacy of cervical disc arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF); however, there are few data referring to adjacent segment within these meta-analyses, or investigators are unable to arrive at the same conclusion in the few meta-analyses about adjacent segment. With the increased concerns surrounding adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) after anterior cervical surgery, it is necessary to perform a comprehensive meta-analysis to analyze adjacent segment parameters. To perform a comprehensive meta-analysis to elaborate adjacent segment motion, degeneration, disease, and reoperation of CDA compared with ACDF. Meta-analysis of randomized controlled trials (RCTs). PubMed, Embase, and Cochrane Library were searched for RCTs comparing CDA and ACDF before May 2016. The analysis parameters included follow-up time, operative segments, adjacent segment motion, ASDeg, ASDis, and adjacent segment reoperation. The risk of bias scale was used to assess the papers. Subgroup analysis and sensitivity analysis were used to analyze the reason for high heterogeneity. Twenty-nine RCTs fulfilled the inclusion criteria. Compared with ACDF, the rate of adjacent segment reoperation in the CDA group was significantly lower (panalysis. There was no statistically significant difference in ASDeg between CDA and ACDF within the 24-month follow-up period; however, the rate of ASDeg in CDA was significantly lower than that of ACDF with the increase in follow-up time (p.05). Cervical disc arthroplasty provided a lower adjacent segment range of motion (ROM) than did ACDF, but the difference was not statistically significant. Compared with ACDF, the advantages of CDA were lower ASDeg and adjacent segment reoperation. However, there was no statistically significant difference in ASDis and adjacent segment ROM. Copyright © 2017 Elsevier Inc. All rights reserved.

Intratracheal Seal Disc

DEFF Research Database (Denmark)

Christiansen, Karen J; Moeslund, Niels; Lauridsen, Henrik

2017-01-01

. The device consisted of an intratracheal silicone seal disc fixated by a cord through the stoma to an external part. At day 14, computed tomography (CT) was performed before the device was extracted. With the pulling of a cord, the disc unraveled into a thin thread and was extracted through the stoma. At day...

Meta-Review of the Quantity and Quality of Evidence for Knee Arthroplasty Devices.

Directory of Open Access Journals (Sweden)

Anna R Gagliardi

Full Text Available Some cardiovascular devices are licensed based on limited evidence, potentially exposing patients to devices that are not safe or effective. Research is needed to ascertain if the same is true of other types of medical devices. Knee arthroplasty is a widely-used surgical procedure yet implant failures are not uncommon. The purpose of this study was to characterize available evidence on the safety and effectiveness of knee implants.A review of primary studies included in health technology assessments (HTA on total (TKA and unicompartmental knee arthroplasty (UKA was conducted. MEDLINE, EMBASE, CINAHL, Cochrane Library and Biotechnology & BioEngineering Abstracts were searched from 2005 to 2014, plus journal tables of contents and 32 HTA web sites. Patients were aged 18 and older who underwent primary TKA or UKA assessed in cohort or randomized controlled studies. Summary statistics were used to report study characteristics.A total of 265 eligible primary studies published between 1986 and 2014 involving 59,217 patients were identified in 10 HTAs (2 low, 7 moderate, 1 high risk of bias. Most evaluated TKA (198, 74.5%. The quality of evidence in primary studies was limited. Most studies were industry-funded (23.8% or offered no declaration of funding or conflict of interest (44.9%; based on uncontrolled single cohorts (58.5%, enrolled fewer than 100 patients (66.4%, and followed patients for 2 years or less (UKA: single cohort 29.8%, comparative cohort 16.7%, randomized trial 25.0%; TKA: single cohort 25.0%, comparative cohort 31.4%, randomized trial 48.6%. Furthermore, most devices were evaluated in only one study (55.3% TKA implants, 61.1% UKA implants.Patients, physicians, hospitals and payers rely on poor-quality evidence to support decisions about knee implants. Further research is needed to explore how decisions about the use of devices are currently made, and how the evidence base for device safety and effectiveness can be strengthened.

78 FR 29156 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...

Science.gov (United States)

2013-05-17

..., and the sale within the United States after importation of certain digital media devices, including... INTERNATIONAL TRADE COMMISSION [Docket No 2954] Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems, Tablets and Mobile Phones, Components Thereof and...

78 FR 36573 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...

Science.gov (United States)

2013-06-18

... importation, and the sale within the United States after importation of certain digital media devices... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-882] Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems, Tablets and Mobile Phones, Components...

Lumbar disc arthroplasty: indications, biomechanics, types, and radiological criteria

International Nuclear Information System (INIS)

Baur-Melnyk, A.; Reiser, M.F.; Birkenmaier, C.

2006-01-01

Lumbar total disc replacement (TDR) was developed to treat a painful degenerative lumbar motion segment while avoiding the disadvantages of fusion surgery, such as adjacent segment instabilities. Early clinical results with TDR have shown a significant reduction in low back pain and a significant improvement in disability scores. When compared to fusion, the results with TDR tend to be superior in the short-term follow-up and initial rehabilitation is faster. The radiological assessment is an integral part of the preoperative work-up. Plain X-rays of the lumbar spine should be complemented by flexion - extension views in order to assess residual segmental mobility. Computed tomography is used to exclude osteoarthritis of the zygapophyseal joints, Baastrup's disease (kissing spines) and other sources of low back pain. Magnetic resonance imaging is useful to exclude substantial disc protrusions; it allows for the detection of disc dehydration and bone marrow edema in the case of activated spondylochondrosis. If osteoporosis is suspected, an osteodensitometry of the lumbar spine should be performed. Postoperative plain X-rays should include antero-posterior and lateral views as well as flexion - extension views in the later postoperative course. Measurements should determine the disc space height in the lateral view, the segmental and total lumbar lordosis as well as the segmental mobility in the flexion - extension views. The ideal position of a TDR is exactly central in the ap-view and close to the dorsal border of the vertebral endplates in the lateral view. Malpositioning may cause segmental hyperlordosis and unbalanced loading of the endplates with the risk of implant subsidence and migration. (orig.) [de

Chiropractic management of patients post-disc arthroplasty: eight case reports

Directory of Open Access Journals (Sweden)

Descarreaux Martin

2010-04-01

Full Text Available Abstract Background When conservative therapies for low back pain (LBP are not effective, elective surgery may be proposed to these patients. Over the last 20 years, a new technology, disc replacement, has become increasingly popular because it is believed to maintain or restore the integrity of spinal movement and minimize the side-effects compared to fusion. Although disc replacement may relieve a patient from pain and related disability, soreness and stiffness of the lumbopelvic region seem to be common aftermaths of the surgery. This prospective case series was undertaken to identify and describe potential adverse events of lumbar spinal manipulation, a common therapy for low back pain, in a group of patients with symptoms after disc prostheses. Cases presentation Eight patients who underwent lumbar spine total disc replacement were referred by an orthopaedic surgeon for chiropractic treatments. These patients had 1 or 2 total lumbar disc replacements and were considered stable according to the surgical protocol but presented persistent, post-surgical, non-specific LBP or pelvic pain. They were treated with lumbar spine side posture manipulations only and received 8 to 10 chiropractic treatments based on the clinical evolution and the chiropractor's judgment. Outcome measures included benign, self-limiting, and serious adverse events after low back spinal manipulative therapy. The Oswestry Disability Index, a pain scale and the fear avoidance belief questionnaire were administered to respectively assess disability, pain and fear avoidance belief about work and physical activity. This prospective case series comprised 8 patients who all had at least 1 total disc replacement at the L4/L5 or L5/S1 level and described persistent post-surgical LBP interfering with their daily activities. Commonly-reported side-effects of a benign nature included increased pain and/or stiffness of short duration in nearly half of the chiropractic treatment period

Effect of initial fluid-system pressures on the behavior of a rupture-disc pressure-relief device

International Nuclear Information System (INIS)

Hsieh, B.J.; Shin, Y.W.; Kot, C.A.

1983-01-01

Rupture disc assemblies are used in piping network systems as a pressure-relief device to protect the system from being exposed to excess pressures. Among the various disc assemblies, the reverse-buckling type is chosen for application in the Clinch River Breeder Reactor. This rupture-disc assembly consists of a portion of a thin spherical shell with its convex side subjected to the fluid system. The reverse-buckling type rupture disc assemblies have been used successfully in environments where the fluid is gas, i.e. highly compressible, and their performances have been judged as adequate in the liquid environment. To analyze the piping system, an analysis method is needed taking into consideration of the fluid/disc interaction, the nonlinear dynamic buckling phenomenon of the disc, and the possible cavitation of the fluid. A computer code SWAAM-I had been written at the Components Technology Division, Argonne National Laboratory. Among its many functions, one is to compute the response of 1-dimensional pressure pulse propagation including the effects of many different types of boundary conditions and possible pipe plasticity

Total ankle arthroplasty: An imaging overview

Energy Technology Data Exchange (ETDEWEB)

Kim, Da Rae; Choi, Yun Sun; Chun, Ka Young; Jung, Yoon Young; Kim, Jin Su; Young, Ki Won [Eulji Hospital, Eulji University, Seoul (Korea, Republic of); Potter, Hollis G.; Li, Angela E. [Dept. of Radiology and Imaging, Hospital for Special Surgery, New York (United States)

2016-06-15

With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice.

M6-C artificial disc placement.

Science.gov (United States)

Coric, Domagoj; Parish, John; Boltes, Margaret O

2017-01-01

There has been a steady evolution of cervical total disc replacement (TDR) devices over the last decade resulting in surgical technique that closely mimics anterior cervical discectomy and fusion as well as disc design that emphasizes quality of motion. The M6-C TDR device is a modern-generation artificial disc composed of titanium endplates with tri-keel fixation as well as a polyethylene weave with a polyurethane core. Although not yet approved by the FDA, M6-C has finished a pilot and pivotal US Investigational Device Exemption (IDE) study. The authors present the surgical technique for implantation of a 2-level M6-C cervical TDR device. The video can be found here: https://youtu.be/rFEAqINLRCo .

Comparison of 2 Zero-Profile Implants in the Treatment of Single-Level Cervical Spondylotic Myelopathy: A Preliminary Clinical Study of Cervical Disc Arthroplasty versus Fusion.

Directory of Open Access Journals (Sweden)

Sheng Shi

Full Text Available Cervical disc arthroplasty (CDA with Discover prosthesis or anterior cervical discectomy and fusion (ACDF with Zero-P cage has been widely used in the treatment of cervical spondylotic myelopathy (CSM. However, little is known about the comparison of the 2 zero-profile implants in the treatment of single-level CSM. The aim was to compare the clinical outcomes and radiographic parameters of CDA with Discover prosthesis and ACDF with Zero-P cage for the treatment of single-level CSM.A total of 128 consecutive patients who underwent 1-level CDA with Discover prosthesis or ACDF with Zero-P cage for single-level CSM between September 2009 and December 2012 were included in this study. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA score and Neck Disability Index (NDI. For radiographic assessment, the overall sagittal alignment (OSA, functional spinal unit (FSU angle, and range of motion (ROM at the index and adjacent levels were measured before and after surgery. Additionally, the complications were also recorded.Both treatments significantly improved all clinical parameters (P 0.05. Besides, no significant differences existed in dysphagia, subsidence, or adjacent disc degeneration between the 2 groups (P > 0.05. However, significant differences occurred in prosthesis migration in CDA group.The results of this study showed that clinical outcomes and radiographic parameters were satisfactory and comparable with the 2 techniques. However, more attention to prosthesis migration of artificial cervical disc should be paid in the postoperative early-term follow-up.

Evaluation of gait performance of knee osteoarthritis patients after total knee arthroplasty with different assistive devices

OpenAIRE

Tereso,Ana; Martins,Maria Manuel; Santos,Cristina Peixoto

2015-01-01

IntroductionNowadays Knee Osteoarthritis (KOA) affects a large percentage of the elderly, and one solution is to perform a Total Knee Arthroplasty (TKA). In this paper, one intends to study the gait and posture of these patients after the TKA, while walking with three assistive devices (ADs) (crutches, standard walker (SW) and rollator with forearm supports (RFS)).MethodsEleven patients were evaluated in 2 phases: 5 days and 15 days after surgery. This evaluation was conducted with two inerti...

78 FR 56736 - Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems...

Science.gov (United States)

2013-09-13

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-882] Certain Digital Media Devices, Including Televisions, Blu-Ray Disc Players, Home Theater Systems, Tablets and Mobile Phones, Components... (``section 337''), in the importation into the United States, the sale for importation, and the sale within...

Rabbit model of intervertebral disc degeneration by external compression device characterized by X-ray, MRI, histology, and cell viability

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Ismail Ismail

2006-12-01

Full Text Available Appropriate experimental animal models, which mimic the degenerative process occurring in human intervertebral disc (IVD breakdown and can be used for new treatment studies such as tissue engineering or disc distraction are lacking. We studied the external compression device that used by Kroeber et al to create intervertebral disc degeneration in rabbit model characterized by X-ray, MRI, Histology, and Cell Viability. Ten NZW rabbit were randomly assigned to one of five groups. Intervertebral disc VL4-L5 are compressed using an external loading device, 1.9 MPa. First group rabbit are loaded for 14 days, second loaded for 28 days, thirth group are loaded for 14 days, and unloaded for 14 days, fourth group loaded for 28 days and unloaded for 28 days. The fifth group, rabbits underwent a sham operation. Additional, rabbits were used as sample for cell viability study. In disc height : sample in group one have biggest decreasing of disc height, that is 23.9 unit. In MRI assessment, the worst grade is grade 3. In histological score, the worst group is group three (58.69, and the best is group 4 (45.69. Group one have the largest dead cell, that are 403.5, and the smallest is group four (124.75. Trypan blue staining showed that group four have better viable cell (91.1 compare than group three (86.4. The study conclude disc degeneration can be created by external axial loading for 14 days in rabbit intervertebral disc. Duration of 28 days unloading gave better result for cells to recover. (Med J Indones 2006; 15:199-207  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Keywords: Rabbit model –intervertebral disc degeneration- external compression device-X-ray, MRI, Histology, and Cell viabilty /* 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

21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

Science.gov (United States)

2010-04-01

... implant). 872.3970 Section 872.3970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3970 Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis...

Seven-year cost-effectiveness of ProDisc-C total disc replacement: results from investigational device exemption and post-approval studies.

Science.gov (United States)

Radcliff, Kris; Lerner, Jason; Yang, Chao; Bernard, Thierry; Zigler, Jack E

2016-05-01

OBJECTIVE The purpose of this study was to evaluate the 7-year cost-effectiveness of cervical total disc replacement (CTDR) versus anterior cervical discectomy and fusion (ACDF) for the treatment of patients with single-level symptomatic degenerative disc disease. A change in the spending trajectory for spine care is to be achieved, in part, through the selection of interventions that have been proven effective yet cost less than other options. This analysis complements and builds upon findings from other cost-effectiveness evaluations of CTDR through the use of long-term, patient-level data from a randomized study. METHODS This was a 7-year health economic evaluation comparing CTDR versus ACDF from the US commercial payer perspective. Prospectively collected health care resource utilization and treatment effects (quality-adjusted life years [QALYs]) were obtained from individual patient-level adverse event reports and SF-36 data, respectively, from the randomized, multicenter ProDisc-C total disc replacement investigational device exemption (IDE) study and post-approval study. Statistical distributions for unit costs were derived from a commercial claims database and applied using Monte Carlo simulation. Patient-level costs and effects were modeled via multivariate probabilistic analysis. Confidence intervals for 7-year costs, effects, and net monetary benefit (NMB) were obtained using the nonparametric percentile method from results of 10,000 bootstrap simulations. The robustness of results was assessed through scenario analysis and within a parametric regression model controlling for baseline variables. RESULTS Seven-year follow-up data were available for more than 70% of the 209 randomized patients. In the base-case analysis, CTDR resulted in mean per-patient cost savings of $12,789 (95% CI $5362-$20,856) and per-patient QALY gains of 0.16 (95% CI -0.073 to 0.39) compared with ACDF over 7 years. CTDR was more effective and less costly in 90.8% of probabilistic

A new distraction arthroplasty device using magnetic force; a cadaveric study.

Science.gov (United States)

Kamei, Goki; Ochi, Mitsuo; Okuhara, Atsushi; Fujimiya, Mineko; Deie, Masataka; Adachi, Nobuo; Nakamae, Atsuo; Nakasa, Tomoyuki; Ohkawa, Shingo; Takazawa, Kobun; Eguchi, Akio; Katou, Tomohiro; Takada, Tsuyoshi; Usman, Muhammad Andry

2013-04-01

It is difficult for an articular cartilage injury to repair spontaneously. There are many procedures for treating cartilage injury, however there is no standard procedure for middle-aged patients who have diffuse knee osteoarthritis, especially of the lateral compartment. Therefore, Ochi developed a new distraction device that uses magnetic power to enlarge a joint space and promote cartilage regeneration with microfracture. The purpose of this study is to evaluate this new distraction arthroplasty system by using the cadaveric knee. This study used ten knees from six cadavers that were embalmed by Thiel's methods. The medial and lateral joint space was measured by AP radiographic view before and after distraction, and after weight-bearing to evaluate the joint distraction. The contact pressure of the medial and lateral compartments at the knee extension position by using a prescale film system was measured before and after weight-bearing with a 15 or 30-kg weight-bearing load to evaluate the effectiveness of this device. The lateral joint space significantly increased from the pre-distraction to the post-distraction; however, it did not change significantly between post-distraction and post-weight-bearing. With a 15 or 30-kg weight-bearing load, the contact pressure of the lateral compartment significantly decreased from the pre-distraction to the post-distraction. The most important advantage of this device is that it maintains a continuous distraction tension and enables almost the full range of motion of the knee. We believe that joint distraction by using magnetic force can be a promising option for cartilage injury in middle-aged patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a clinically relevant impingement test method for a mobile bearing lumbar total disc replacement.

Science.gov (United States)

Siskey, Ryan; Peck, Jonathan; Mehta, Hitesh; Kosydar, Allison; Kurtz, Steven; Hill, Genevieve

2016-09-01

Total disc arthroplasty is an alternative therapy to spinal fusion for the treatment of neck or low back pain and is hypothesized to reduce the risk of disease progression to the adjacent spinal levels. Radiographic and retrieval analyses of various total disc replacements (TDRs) have shown evidence of impingement damage. Impingement of TDRs can occur when the device reaches the limits of its functional range of motion, causing contact between peripheral regions of the device. Impingement can be associated with increased wear and mechanical damage; however, impingement conditions are not simulated in current standardized mechanical bench test methods. This study explored the test conditions necessary to apply clinically relevant impingement loading to a lumbar TDR in vitro. An experimental protocol was developed and evaluated using in vivo retrievals for qualitative and quantitative validation. Retrieval analysis was conducted on a set of 11 size 3 retrieved Charité devices using American Society for Testing and Materials F561 as a guide. The impingement range of motion was determined using a combination of modeling and experiments, and was used as an input in vitro testing. A 1-million cycle in vitro test was then conducted, and the in vitro samples were characterized using methods similar to the retreived devices. All in vitro tested samples exhibited impingement regions and damage patterns consistent with retrieved devices. Consistent with the retrievals, the impingement damage on the rim was a combination of abrasive wear and plastic deformation. Micro computed tomography (microCT) was used to quantitatively assess rim damage due to impingement. Rim penetration was statistically lower in the retrievals when compared with both in vitro groups. Rim elongation was comparable among all groups. The simulated-facet group had statistically greater angular rim deformations than the retrieval group and the no-facet group. Results demonstrate that clinically relevant

An evaluation of information on the internet about a new device: the cervical artificial disc replacement.

Science.gov (United States)

Qureshi, Sheeraz A; Koehler, Steven M; Lin, James D; Bird, Justin; Garcia, Ryan M; Hecht, Andrew C

2012-05-01

Cross-sectional survey. The objective of this study was to investigate the authorship, content, and quality of information available to the public on the Internet pertaining to the cervical artificial disc replacement device. The Internet is widely used by patients as an educational tool for health care information. In addition, the Internet is used as a medium for direct-to-consumer marketing. Increasing interest in cervical artificial disc replacement has led to the emergence of numerous Web sites offering information about this procedure. It is thought that patients can be influenced by information found on the Internet. A cross section of Web sites accessible to the general public was surveyed. Three commonly used search engines were used to locate 150 (50/search engine) Web sites providing information about the cervical artificial disc replacement. Each Web site was evaluated with regard to authorship and content. Fifty-three percent of the Web sites reviewed were authorized by a private physician group, 4% by an academic physician group, 13% by industry, 16% were news reports, and 14% were not otherwise categorized. Sixty-five percent of Web sites offered a mechanism for direct contact and 19% provided clear patient eligibility criteria. Benefits were expressed in 80% of Web sites, whereas associated risks were described in 35% or less. European experiences were noted in 17% of Web sites, whereas only 9% of Web sites detailed the current US experience. CONCLUSION.: The results of this study demonstrate that much of the content of the Internet-derived information pertaining to the cervical artificial disc replacement is for marketing purposes and may not represent unbiased information. Until we can confirm the content on a Web site to be accurate, patients should be cautioned when using the Internet as a source for health care information related to cervical disc replacement.

Robust control of a compact disc mechanism

NARCIS (Netherlands)

Steinbuch, M.; Schootstra, G.; Bosgra, O.H.; Levine, W.S.

1995-01-01

A compact disc (CD) player is an optical decoding device that reproduces high-quality audio from a digitally coded signal recorded as a spiral-shaped track on a reflective disc. Apart from the audio application, other optical data systems (CD-ROM, optical data drive) and combined audio/video

Development of rupture discs for the FBTR

International Nuclear Information System (INIS)

Chetal, S.C.; Raju, C.; Anandkumar, V.; Seetharaman, V.; Rajan, K.K.

1984-01-01

Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. Reverse buckling knife blade concept with austenitic stainless steel disc has been developed for the rupture disc assemblies required for Fast Breeder Test Reactor (FBTR). Hydroforming process without any die has been used for disc fabrication. One rupture disc assembly required for steam generator is undergoing sodium endurance test and has accumulated 4,500 hours. The present status of development work as demonstrated by room temperature experimental results as well as the scope for future work are discussed. (author)

Innovations in design and technology. The story of hip arthroplasty.

Science.gov (United States)

Amstutz, H C

2000-09-01

The current study reviews the early history of surgeon-initiated trial and error development in hip joint arthroplasty and the subsequent methodological evolution to proper criteria for hypothesis testing using bioengineers and other research scientists. The interplay and relationships to industry, universities, scientific organizations, and the Food and Drug Administration with respect to device development in hip arthroplasty are reviewed. The ethics of and responsibilities to involved parties are outlined, citing the history of many contemporary developments. Examples are provided from the evolution and introduction of unsuccessful innovations, and the problems inherent in the current methodology of the approval process from the Food and Drug Administration using the 5-10K, Investigative Device Exemption, and the Pre-Market Approval protocols. The pros and cons of randomized trials for devices are outlined with the conclusion that they are not appropriate for device introduction. The proper, rational methodology for introduction of new devices is a phased-in clinical trial process after pertinent bench testing. Finally, the ethical dilemmas created by managed care are addressed. Industry involvements of the surgeon-spokesmen are cited.

Mobile compression devices and aspirin for VTE prophylaxis following simultaneous bilateral total knee arthroplasty.

Science.gov (United States)

Nam, Denis; Nunley, Ryan M; Johnson, Staci R; Keeney, James A; Barrack, Robert L

2015-03-01

Recently, Levy et al questioned the effectiveness of mobile compression devices (MCDs) as the sole method of thromboprophylaxis following simultaneous bilateral total knee arthroplasty (TKA). This study's purpose was to assess if the addition of aspirin to MCDs improves venous thromboembolism (VTE) prevention following simultaneous bilateral TKA. Ninety-six patients (192 TKAs) were retrospectively reviewed: 47 patients received MCDs for 10 days and aspirin for 6 weeks postoperatively based on a risk stratification protocol, while 49 patients received warfarin for 4 weeks postoperatively. One symptomatic VTE was noted in the warfarin cohort, while one patient in the MCD/aspirin cohort and three patients in the warfarin cohort were readmitted within 3 months of surgery. In appropriately selected patients, MCDs with aspirin shows promise in VTE prevention following simultaneous bilateral TKA. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparative Study Between M6-C and Mobi-C Cervical Artificial Disc Replacement: Biomechanical Outcomes and Comparison with Normative Data.

Science.gov (United States)

Pham, My; Phan, Kevin; Teng, Ian; Mobbs, Ralph J

2018-05-01

Cervical spondylosis affects a huge proportion of the middle-aged population. Degenerative changes can occur in multiple regions of the cervical spine typically affecting the joints, intervertebral discs and endplates. These changes lead to compression of adjacent nervous structures, which results in radiculopathic and myelopathic pain. Various treatment modalities are currently available with non-surgical approaches the initial go to if there is no symptomatic cord compression. Anterior cervical discectomy and fusion, or arthroplasty are the two common surgical approaches if non-surgical treatments fail to relieve symptoms of the patients or there are signs of central cord compression. However, studies have shown that there is an increased risk of adjacent segment disease related to fusion. Cervical disc arthroplasty aims to restore normal range of motion (ROM) in patients with pain and disability due to degenerative disc disease resistant to conservative care. Two common disc prostheses used include M6-C and Mobi-C. Both prostheses comprise a mobile polymer segment sandwiched between two metal endplates with mechanisms resembling an actual intervertebral disc. This study aims to compare the kinematics associated with these prostheses, against the normal range of motion in the non-degenerative population. Patients who underwent M6-C or Mobi-C disc replacements by the senior author from 2012 to 2015 were identified at a single tertiary institution. Routine 3-month postoperative lateral radiographs were analyzed for flexion and extension ROM angles at the involved vertebral level by two independent authors. Data was compared to previous published studies investigating cervical spine ROM of asymptomatic patients. There was no statistical significance in the difference of overall flexion range between M6-C and Mobi-C prostheses. However, overall range of extension of Mobi-C was greater compared to M6-C (P = 0.028). At C 5-6 , the range of flexion for both implants

Ablation of intervertebral discs in dogs using a MicroJet-assisted dye-enhanced injection device coupled with the diode laser

Science.gov (United States)

Bartels, Kenneth E.; Henry, George A.; Dickey, D. Thomas; Stair, Ernest L.; Powell, Ronald; Schafer, Steven A.; Nordquist, Robert E.; Frederickson, Christopher J.; Hayes, Donald J.; Wallace, David B.

1998-07-01

Use of holmium laser energy for vaporization/coagulation of the nucleus pulposus in canine intervertebral discs has been previously reported and is currently being applied clinically in veterinary medicine. The procedure was originally developed in the canine model and intended for potential human use. Since the pulsed (15 Hz) holmium laser energy exerts photomechanical and photothermal effects, the potential for extrusion of additional disc material to the detriment of the patient is possible using the procedure developed for the dog. To reduce this potential complication, use of diode laser (805 nm - CW mode) energy, coupled with indocyanine green (ICG) as a selective laser energy absorber, was formulated as a possible alternative. Delivery of the ICG and diode laser energy was through a MicroJet device that could dispense dye interactively between individual laser 'shots.' Results have shown that it is possible to selectively ablate nucleus pulposus in the canine model using the device described. Acute observations (gross and histopathologic) illustrate that accurate placement of the spinal needle before introduction of the MicroJet device is critically dependent on the expertise of the interventional radiologist. In addition, the success of the overall technique depends on consistent delivery of both ICG and diode laser energy. Minimizing tissue carbonization on the tip of the MicroJet device is also of crucial importance for effective application of the technique in clinical veterinary medicine.

21 CFR 866.1620 - Antimicrobial susceptibility test disc.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Antimicrobial susceptibility test disc. 866.1620 Section 866.1620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1620 Antimicrobial...

The Synovial Lining and Synovial Fluid Properties after Joint Arthroplasty

Directory of Open Access Journals (Sweden)

Michael Shang Kung

2015-05-01

Full Text Available The lubrication of the cartilaginous structures in human joints is provided by a fluid from a specialized layer of cells at the surface of a delicate tissue called the synovial lining. Little is known about the characteristics of the fluids produced after a joint arthroplasty procedure. A literature review was carried out to identify papers that characterized the synovial lining and the synovial fluids formed after total hip or knee arthroplasty. Five papers about synovial lining histology and six papers about the lubricating properties of the fluids were identified. The cells making up the re-formed synovial lining, as well as the lining of interface membranes, were similar to the typical Type A and B synoviocytes of normal joints. The synovial fluids around joint replacement devices were typically lower in viscosity than pre-arthroplasty fluids but the protein concentration and phospholipid concentrations tended to be comparable, suggesting that the lining tissue function was preserved after arthroplasty. The widespread, long-term success of joint arthroplasty suggests that the lubricant formed from implanted joint synovium is adequate for good clinical performance in the majority of joints. The role the fluid plays in component wear or failure is a topic for future study.

Management of temporomandibular joint ankylosis with combination of gap arthroplasty surgery and physiotherapy

Directory of Open Access Journals (Sweden)

Nurul Ramadhanty

2017-08-01

Full Text Available Background. Temporomandibular joint (TMJ ankylosis is a union of the articular surface of the temporal bone to the disc-condyle complex that restricts mandibular movements due to either a fibrous or bony union between the head of the condyle and the glenoid fossa. Common etiological factors are trauma, infection, and pathology in the joint or systemic diseases. The diagnosis of TMJ ankylosis is established through physical and clinical evaluation, and imaging examination. Currently, the surgical techniques used to treat TMJ ankylosis are gap arthroplasty, interpositional arthroplasty, joint reconstruction, and distraction osteogenesis. Purpose. To provide overview about management of temporomandibular joint ankylosis with gap arthroplasty combined with physiotherapy post surgery. Case. A 12-year-old female patient came to Department of Oral and Maxillofacial Surgery with complaint of opening mouth restriction, which occured since one year prior to admission. After complete physical and radiographic examination, patient then was diagnosed with TMJ ankylosis due to neglected odontogenic infection. The treatment was performed with gap arthroplasty under general anesthesia. Patient then underwent physiotherapy after the surgery, including application of heat on the affected region and exercises to open and close mouth. Discussion. Ankylosis of TMJ is an uncommon case that results in chronic and severe limited mouth opening. The critical factor of successful treatment of TMJ ankylosis is early detection, correct surgery approach, implementation of an intensive physiotherapy program, and a good post-operative conduct. Therefore on this patient, gap arthroplasty was the chosen surgery approach followed by intensive physiotherapy. Conclusion.Management goal in TMJ ankylosis is  to increase the patient’s mandibular function, correct associated facial deformity, decrease pain, and prevent reankylosis. Careful surgical technique and subsequent atten

Optical sensing system based on wireless paired emitter detector diode device and ionogels for lab-on-a-disc water quality analysis.

Science.gov (United States)

Czugala, Monika; Gorkin, Robert; Phelan, Thomas; Gaughran, Jennifer; Curto, Vincenzo Fabio; Ducrée, Jens; Diamond, Dermot; Benito-Lopez, Fernando

2012-12-07

This work describes the first use of a wireless paired emitter detector diode device (PEDD) as an optical sensor for water quality monitoring in a lab-on-a-disc device. The microfluidic platform, based on an ionogel sensing area combined with a low-cost optical sensor, is applied for quantitative pH and qualitative turbidity monitoring of water samples at point-of-need. The autonomous capabilities of the PEDD system, combined with the portability and wireless communication of the full device, provide the flexibility needed for on-site water testing. Water samples from local fresh and brackish sources were successfully analysed using the device, showing very good correlation with standard bench-top systems.

Soft-tissue tension total knee arthroplasty.

Science.gov (United States)

Asano, Hiroshi; Hoshino, Akiho; Wilton, Tim J

2004-08-01

It is far from clear how best to define the proper strength of soft-tissue tensioning in total knee arthroplasty (TKA). We attached a torque driver to the Monogram balancer/tensor device and measured soft-tissue tension in full extension and 90 degrees flexion during TKA. In our surgical procedure, when we felt proper soft-tissue tension was being applied, the mean distraction force was noted to be 126N in extension and 121N in flexion. There was no significant correlation between soft-tissue tension and the postoperative flexion angle finally achieved. To the best of our knowledge, this is the first study to assess the actual distraction forces in relation to soft-tissue tension in TKA. Further study may reveal the most appropriate forces to achieve proper soft-tissue tension in the wide variety of circumstances presenting at knee arthroplasty.

Implant survival of the most common cemented total hip devices from the Nordic Arthroplasty Register Association database

DEFF Research Database (Denmark)

Junnila, Mika; Laaksonen, Inari; Eskelinen, Antti

2016-01-01

Background and purpose - According to previous Nordic Arthroplasty Register Association (NARA) data, the 10-year implant survival of cemented total hip arthroplasties (THAs) is 94% in patients aged 65-74 and 96% in patients aged 75 or more. Here we report a brand-level comparison of cemented THA...

Difference in occurrence of heterotopic ossification according to prosthesis type in the cervical artificial disc replacement.

Science.gov (United States)

Yi, Seong; Kim, Keung Nyun; Yang, Moon Sul; Yang, Joong Won; Kim, Hoon; Ha, Yoon; Yoon, Do Heum; Shin, Hyun Chul

2010-07-15

Retrospective study of the difference of heterotopic ossification (HO) occurrence according to 3 different types of prosthesis. This study was designed to investigate the difference of HO occurrence according to different type of prosthesis. HO is defined as formation of the bone outside the skeletal system. Reported HO occurrence rate in cervical artificial disc replacement (ADR) was unexpectedly high and varied. But the influencing factors of HO in cervical ADR have not been elucidated well. The prosthesis-related factors for making difference of HO occurrence were investigated in this study. A total of 170 patients undergoing cervical arthroplasty with the Bryan cervical disc prosthesis (Medtroic Sofamor Danek, Memphis, TN), Mobi-C disc prosthesis (LDR Medical, Troyes, France), and ProDisc-C (Synthes, Inc., West Chester, PA) were included. Cervical lateral radiographs obtained before and after surgery were used to identify HO. Occurrence rate, occurrence-free period, location, and grade of HOs were investigated according to the different prosthesis. Each prosthesis group included patients as follows: Bryan disc, 81 patients; Mobi-C, 61 patients; and ProDisc-C, 28 patients. Overall HO rate was 40.6% (69 of 170 patients). Each HO occurrence rate by prosthesis was as follows: the Bryan disc group, 21.0%; Mobi-C group, 52.5%; and the ProDisc-C group, 71.4%. In the survival analysis, all patients showed 27.1 +/- 3.7 months as the median survival. The Bryan disc group showed statistically longer survival (48.4 +/- 7.4 months) than the other groups. Occurrence of HO is an inevitable postoperative complication after cervical ADR. The occurrence rate of HO was higher than our expectation. Moreover, definite differences in occurrence rate according to the prosthesis type were identified by this study.

Human and bovine spinal disc mechanics subsequent to trypsin injection

Directory of Open Access Journals (Sweden)

Jeremy Alsup

2017-10-01

The Translational Potential of this Article: Preclinical testing of novel spinal devices is essential to the design validation and regulatory processes, but current testing techniques rely on cadaveric testing of primarily older spines with essentially random amounts of disc degeneration. The present work investigates the viability of using trypsin injections to create a more uniform preclinical model of disc degeneration from a mechanics perspective, for the purpose of testing spinal devices. Such a model would facilitate translation of new spinal technologies to clinical practice.

Indigenous development of rupture discs for FBTR (Paper No. 028)

International Nuclear Information System (INIS)

Chetal, S.C.; Raju, Chander; Anandkumar, V.; Seetharaman, V.

1987-02-01

Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water-steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. As an import substitution of the costly items for the FBTR Project, development of the rupture disc assemblies has been in progress at Indira Gandhi Centre for Atomic Research, Kalpakkam. Reverse buckling knife blade concept with stainless steel disc has been taken up for development. Hydroforming process without any die has been selected for disc fabrication. One rupture disc assembly required for steam generator has been tested in sodium satisfactorily. (author). 4 tables, 5 figs

Total disc replacement using tissue-engineered intervertebral discs in the canine cervical spine.

Directory of Open Access Journals (Sweden)

Yu Moriguchi

Full Text Available The most common reason that adults in the United States see their physician is lower back or neck pain secondary to degenerative disc disease. To date, approaches to treat degenerative disc disease are confined to purely mechanical devices designed to either eliminate or enable flexibility of the diseased motion segment. Tissue engineered intervertebral discs (TE-IVDs have been proposed as an alternative approach and have shown promise in replacing native IVD in the rodent tail spine. Here we demonstrate the efficacy of our TE-IVDs in the canine cervical spine. TE-IVD components were constructed using adult canine annulus fibrosis and nucleus pulposus cells seeded into collagen and alginate hydrogels, respectively. Seeded gels were formed into a single disc unit using molds designed from the geometry of the canine spine. Skeletally mature beagles underwent discectomy with whole IVD resection at levels between C3/4 and C6/7, and were then divided into two groups that received only discectomy or discectomy followed by implantation of TE-IVD. Stably implanted TE-IVDs demonstrated significant retention of disc height and physiological hydration compared to discectomy control. Both 4-week and 16-week histological assessments demonstrated chondrocytic cells surrounded by proteoglycan-rich matrices in the NP and by fibrocartilaginous matrices in the AF portions of implanted TE-IVDs. Integration into host tissue was confirmed over 16 weeks without any signs of immune reaction. Despite the significant biomechanical demands of the beagle cervical spine, our stably implanted TE-IVDs maintained their position, structure and hydration as well as disc height over 16 weeks in vivo.

Human and bovine spinal disc mechanics subsequent to trypsin injection.

Science.gov (United States)

Alsup, Jeremy; Bishop, Timothy; Eggett, Dennis; Bowden, Anton E

2017-10-01

To investigate the biomechanical effects of injections of a protease on the characteristics of bovine coccygeal and human lumbar disc motion segments. Mechanics of treated tissues were measured immediately after injection and 3 h after injection. Motion segments underwent axial rotation and flexion-extension loading. Stiffness and neutral zone parameters experienced significant changes over time, with bovine tissues more strongly affected than human cadaver tissues. This was true in both axial rotation and flexion-extension. The treatment type significantly affected the neutral zone measurements in axial rotation. Hysteresis parameters were impacted by control injections. The extrapolation of bovine coccygeal motion testing results to human lumbar disc mechanics is not yet practical. The injected treatment may have a smaller impact on disc mechanics than time in testing. Viscoelasticity of human lumbar discs may be impacted by any damage to the annulus fibrosis induced by needlestick. Preclinical testing of novel spinal devices is essential to the design validation and regulatory processes, but current testing techniques rely on cadaveric testing of primarily older spines with essentially random amounts of disc degeneration. The present work investigates the viability of using trypsin injections to create a more uniform preclinical model of disc degeneration from a mechanics perspective, for the purpose of testing spinal devices. Such a model would facilitate translation of new spinal technologies to clinical practice.

Disc defect classification for optical disc drives

NARCIS (Netherlands)

Helvoirt, van J.; Leenknegt, G.A.L.; Steinbuch, M.; Goossens, H.J.

2005-01-01

Optical disc drives are subject to various disturbances and faults. A special type of fault is the so-called disc defect. In this paper we present an approach for disc defect classification. It is based on hierarchical clustering of measured signals that are affected by disc defects. The

[Sports participation after joint arthroplasty].

Science.gov (United States)

Dauty, M; Letenneur, J

2007-12-01

To recommand sports activities after joint arthroplasty from the literature analysis, the French surgeon's opinion and wish patients. From the Medline data base interrogation according to keywords: Sports, Arthroplasty, Athletics, Physical training, two different readers, an orthopedic surgeon and a Physical Medicine and Rehabilitation physician selected articles in French or English language according to the level of proofs of the french classification of the Accreditation and Health Evaluation National Agency (Anaes). Professional practices were estimated by the interrogation of 30 orthopedic surgeons members of the french West Orthopaedics Society (SOO). The demand of sports practice was studied with patients recently operated for a primary total knee arthroplasty (TKA) after gonarthrosis. Twenty-two articles were selected from 305 articles obtained by the search according to keywords. Ten literature reviews are limited by the absence of prospective randomized study. A level II study and eleven level IV articles are reported. According to the subjective orthropedic surgeon's opinion, the objective results based on the joint load studied and the percentage of arthroplasty revision, sport is beneficial for the individual health but perhaps not for the arthroplasty survey. However, aerobic and leisure activities are recommended (walking, swimming, cycling) in agreement with the demand of the patients recently operated with a TKA. TKA differs from Total Hip Arthroplasty for jogging because of knee joint constraints during the knee flexion. A single study reports sports possibilities after shoulder arthroplasty and ankle arthroplasty and no study reports results after elbow arthroplasty.

Prospective, randomized multicenter study of cervical arthroplasty versus anterior cervical discectomy and fusion: 5-year results with a metal-on-metal artificial disc.

Science.gov (United States)

Coric, Domagoj; Guyer, Richard D; Nunley, Pierce D; Musante, David; Carmody, Cameron; Gordon, Charles; Lauryssen, Carl; Boltes, Margaret O; Ohnmeiss, Donna D

2018-03-01

OBJECTIVE Seven cervical total disc replacement (TDR) devices have received FDA approval since 2006. These devices represent a heterogeneous assortment of implants made from various biomaterials with different biomechanical properties. The majority of these devices are composed of metallic endplates with a polymer core. In this prospective, randomized multicenter study, the authors evaluate the safety and efficacy of a metal-on-metal (MoM) TDR (Kineflex|C) versus anterior cervical discectomy and fusion (ACDF) in the treatment of single-level spondylosis with radiculopathy through a long-term (5-year) follow-up. METHODS An FDA-regulated investigational device exemption (IDE) pivotal trial was conducted at 21 centers across the United States. Standard validated outcome measures including the Neck Disability Index (NDI) and visual analog scale (VAS) for assessing pain were used. Patients were randomized to undergo TDR using the Kineflex|C cervical artificial disc or anterior cervical fusion using structural allograft and an anterior plate. Patients were evaluated preoperatively and at 6 weeks and 3, 6, 12, 24, 36, 48, and 60 months after surgery. Serum ion analysis was performed on a subset of patients randomized to receive the MoM TDR. RESULTS A total of 269 patients were enrolled and randomly assigned to undergo either TDR (136 patients) or ACDF (133 patients). There were no significant differences between the TDR and ACDF groups in terms of operative time, blood loss, or length of hospital stay. In both groups, the mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the 60-month follow-up (both p < 0.01). Similarly, VAS pain scores improved significantly by 6 weeks and remained significantly improved through the 60-month follow-up (both p < 0.01). There were no significant changes in outcomes between the 24- and 60-month follow-ups in either group. Range of motion in the TDR group decreased at 3 months but

Unicompartmental knee arthroplasty

NARCIS (Netherlands)

Kort, Nanne Pieter

2007-01-01

This thesis concerns technical aspects of unicompartmental knee arthroplasty. Recent years have witnessed a resurgence of interest in unicompartmental arthroplasty, particularly with the introduction of the minimally invasive technique. In the light of the excellent long-term results of the total

Reverse-total shoulder arthroplasty cost-effectiveness: A quality-adjusted life years comparison with total hip arthroplasty.

Science.gov (United States)

Bachman, Daniel; Nyland, John; Krupp, Ryan

2016-02-18

To compare reverse-total shoulder arthroplasty (RSA) cost-effectiveness with total hip arthroplasty cost-effectiveness. This study used a stochastic model and decision-making algorithm to compare the cost-effectiveness of RSA and total hip arthroplasty. Fifteen patients underwent pre-operative, and 3, 6, and 12 mo post-operative clinical examinations and Short Form-36 Health Survey completion. Short form-36 Health Survey subscale scores were converted to EuroQual Group Five Dimension Health Outcome scores and compared with historical data from age-matched patients who had undergone total hip arthroplasty. Quality-adjusted life year (QALY) improvements based on life expectancies were calculated. The cost/QALY was $3900 for total hip arthroplasty and $11100 for RSA. After adjusting the model to only include shoulder-specific physical function subscale items, the RSA QALY improved to 2.8 years, and its cost/QALY decreased to $8100. Based on industry accepted standards, cost/QALY estimates supported both RSA and total hip arthroplasty cost-effectiveness. Although total hip arthroplasty remains the quality of life improvement "gold standard" among arthroplasty procedures, cost/QALY estimates identified in this study support the growing use of RSA to improve patient quality of life.

Material Science in Cervical Total Disc Replacement

Science.gov (United States)

Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

Material Science in Cervical Total Disc Replacement.

Science.gov (United States)

Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

The Danish Hip Arthroplasty Register

DEFF Research Database (Denmark)

Gundtoft, Per Hviid; Varnum, Claus; Pedersen, Alma Becic

2016-01-01

AIM OF DATABASE: The aim of the Danish Hip Arthroplasty Register (DHR) is to continuously monitor and improve the quality of treatment of primary and revision total hip arthroplasty (THA) in Denmark. STUDY POPULATION: The DHR is a Danish nationwide arthroplasty register established in January 1995...

Rapid Detection of Salmonella enterica in Food Using a Compact Disc-Shaped Device

Directory of Open Access Journals (Sweden)

Shunsuke Furutani

2016-01-01

Full Text Available Rapid detection of food-borne pathogens is essential to public health and the food industry. Although the conventional culture method is highly sensitive, it takes at least a few days to detect food-borne pathogens. Even though polymerase chain reaction (PCR can detect food-borne pathogens in a few hours, it is more expensive and unsatisfactorily sensitive relative to the culture method. We have developed a method to rapidly detect Salmonella enterica by using a compact disc (CD-shaped device that can reduce reagent consumption in conventional PCR. The detection method, which combines culture and PCR, is more rapid than the conventional culture method and is more sensitive and cheaper than PCR. In this study, we also examined a sample preparation method that involved collecting bacterial cells from food. The bacteria collected from chicken meat spiked with S. enterica were mixed with PCR reagents, and PCR was performed on the device. At a low concentration of S. enterica, the collected S. enterica was cultured before PCR for sensitive detection. After cultivation for 4 h, S. enterica at 1.7 × 104 colony-forming units (CFUs·g−1 was detected within 8 h, which included the time needed for sample preparation and detection. Furthermore, the detection of 30 CFUs·g−1 of S. enterica was possible within 12 h including 8 h for cultivation.

Comparison of Animal Discs Used in Disc Research to Human Lumbar Disc: Torsion Mechanics and Collagen Content

Science.gov (United States)

Showalter, Brent L.; Beckstein, Jesse C.; Martin, John T.; Beattie, Elizabeth E.; Orías, Alejandro A. Espinoza; Schaer, Thomas P.; Vresilovic, Edward J.; Elliott, Dawn M.

2012-01-01

Study Design Experimental measurement and normalization of in vitro disc torsion mechanics and collagen content for several animal species used in intervertebral disc research and comparing these to the human disc. Objective To aid in the selection of appropriate animal models for disc research by measuring torsional mechanical properties and collagen content. Summary of Background Data There is lack of data and variability in testing protocols for comparing animal and human disc torsion mechanics and collagen content. Methods Intervertebral disc torsion mechanics were measured and normalized by disc height and polar moment of inertia for 11 disc types in 8 mammalian species: the calf, pig, baboon, goat, sheep, rabbit, rat, and mouse lumbar, and cow, rat, and mouse caudal. Collagen content was measured and normalized by dry weight for the same discs except the rat and mouse. Collagen fiber stretch in torsion was calculated using an analytical model. Results Measured torsion parameters varied by several orders of magnitude across the different species. After geometric normalization, only the sheep and pig discs were statistically different from human. Fiber stretch was found to be highly dependent on the assumed initial fiber angle. The collagen content of the discs was similar, especially in the outer annulus where only the calf and goat discs were statistically different from human. Disc collagen content did not correlate with torsion mechanics. Conclusion Disc torsion mechanics are comparable to human lumbar discs in 9 of 11 disc types after normalization by geometry. The normalized torsion mechanics and collagen content of the multiple animal discs presented is useful for selecting and interpreting results for animal models of the disc. Structural composition of the disc, such as initial fiber angle, may explain the differences that were noted between species after geometric normalization. PMID:22333953

Loop-Mediated Isothermal Amplification Using a Lab-on-a-Disc Device with Thin-film Phase Change Material.

Science.gov (United States)

Ko, Junguk; Yoo, Jae-Chern

2018-03-05

The design and fabrication of temperature measurement systems that facilitate successful realization of DNA amplification using a lab-on-a-disc (LOD) device are a highly challenging task. The major challenge lies in the fact that such a system must be directly attached to a heating chamber in a way that enables the accurate measurement of temperature of the chamber while allowing the LOD to rotate. This paper presents a temperature control system for implementing isothermal amplification of DNA samples using an LOD device. The proposed system utilizes a thin-film phase change material and non-contact heating system to remotely measure the actual temperature of the chamber and, if required, rapidly heat it to the desired temperature. The results of the experiments performed in this study demonstrate that the proposed system provides an automated platform for molecular amplification and exhibits an operational performance comparable to that of traditional microcentrifuge tube-based isothermal amplification systems.

The Warwick patellofemoral arthroplasty trial: a randomised clinical trial of total knee arthroplasty versus patellofemoral arthroplasty in patients with severe arthritis of the patellofemoral joint

Directory of Open Access Journals (Sweden)

Odumenya Michelle

2011-11-01

Full Text Available Abstract Background Severe arthritis of the knee is a disabling condition, with over 50,000 knee replacements performed each year in the UK. Isolated patellofemoral joint arthritis occurs in over 10% of these patients with the treatment options being patellofemoral arthroplasty or total knee arthroplasty. Whilst many surgeons believe total knee arthroplasty is the 'gold standard' treatment for severe knee arthritis, patellofemoral arthroplasty has certain potential advantages. Primarily, because this operation allows the patient to keep the majority of their own knee joint; preserving bone-stock and the patients' own ligaments. Patellofemoral arthroplasty has also been recognised as a less 'invasive' operation than primary total knee arthroplasty, facilitating a more rapid recovery. There are currently no published results of randomised clinical trials comparing the two arthroplasty techniques. The primary objective of the current study is to assess whether there is a difference in functional knee scores and quality of life outcome assessments at one year post-operation between patellofemoral arthroplasty and total knee arthroplasty. The secondary objective is to assess the complication rates for both procedures. Methods/design Patients who are deemed suitable, by an Orthopaedic Consultant, for patellofemoral arthroplasty and medically fit for surgery are eligible to take part in this trial. The consenting patients will be randomised in a 1:1 allocation to a total knee or patellofemoral arthroplasty. The randomisation sequence will be computer generated and administered by a central independent randomisation service. Following consent, all participants will have their knee function, quality of life and physical activity level assessed through questionnaires. The assigned surgery will then be performed using the preferred technique and implant of the operating surgeon. The first post-operative assessments will take place at six weeks, followed by

Sagittal alignment after single cervical disc arthroplasty.

Science.gov (United States)

Guérin, Patrick; Obeid, Ibrahim; Gille, Olivier; Bourghli, Anouar; Luc, Stéphane; Pointillart, Vincent; Vital, Jean-Marc

2012-02-01

Prospective study. To analyze the sagittal balance after single-level cervical disc replacement (CDR) and range of motion (ROM). To define clinical and radiologic parameters those have a significant correlation with segmental and overall cervical curvature after CDR. Clinical outcomes and ROM after CDR with Mobi-C (LDR, Troyes, France) prosthesis have been documented in few studies. No earlier report of this prosthesis has studied correlations between static and dynamic parameters or those between static parameters and clinical outcomes. Forty patients were evaluated. Clinical outcome was assessed using the Short Form-36 questionnaire, Neck Disability Index, and a Visual Analog Scale. Spineview software (Surgiview, Paris, France) was used to investigate sagittal balance parameters and ROM. The mean follow-up was 24.3 months (range: 12 to 36 mo). Clinical outcomes were satisfactory. There was a significant improvement of Short Form-36, Neck Disability Index, and Visual Analog Scale scores. Mean ROM was 8.3 degrees preoperatively and 11.0 degrees postoperatively (P=0.013). Mean preoperative C2C7 curvature was 12.8 and 16.0 degrees at last follow-up (P=0.001). Mean preoperative functional spinal unit (FSU) angle was 2.3 and 5.3 degrees postoperatively (P<0.0001). Mean postoperative shell angle was 5.5 degrees. There was a significant correlation between postoperative C2C7 alignment and preoperative C2C7 alignment, change of C2C7 alignment, preoperative and postoperative FSU angle, and prosthesis shell angle. There was also a significant correlation between postoperative FSU angle and preoperative C2C7 alignment, preoperative FSU angle, change of FSU angle, and prosthesis shell angle. Regression analysis showed that prosthesis shell angle and preoperative FSU angle contributed significantly to postoperative FSU angle. Moreover, preoperative C2C7 alignment, preoperative FSU angle, postoperative FSU angle, and prosthesis shell angle contributed significantly to

Material Science in Cervical Total Disc Replacement

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Martin H. Pham

2015-01-01

Full Text Available Current cervical total disc replacement (TDR designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti, and cobalt-chrome (CoCr. These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Adjacent segment disease and C-ADR: promises fulfilled?

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Riew, K Daniel; Schenk-Kisser, Jeannette M.; Skelly, Andrea C.

2012-01-01

Study design: Systematic review. Clinical question: Do the rates and timing of adjacent segment disease (ASD) differ between cervical total disc arthroplasty (C-ADR) and anterior cervical discectomy and fusion (ACDF) in patients treated for cervical degenerative disc disease? Methods: A systematic search of MEDLINE/PubMed and bibliographies of key articles was done to identify studies with long-term follow-up for symptomatic and/or radiographic ASD comparing C-ADR with fusion for degenerative disc disease of the cervical spine. The focus was on studies with longer follow-up (48–60 months) of primary US Food and Drug Administration trials of Prestige ST, Prodisc-C, and Bryan devices as available. Trials of other discs with a minimum of 24 months follow-up were considered for inclusion. Studies evaluating lordosis/angle changes at adjacent segments and case series were excluded. Results: From 14 citations identified, four reports from three randomized controlled trials and four nonrandomized studies are summarized. Risk differences between C-ADR and ACF for symptomatic ASD were 1.5%–2.3% and were not significant across RCT reports. Time to development of ASD did not significantly differ between treatments. Rates of radiographic ASD were variable. No meaningful comparison of ASD rates based on disc design was possible. No statistical differences in adjacent segment range of motion were noted between treatment groups. Conclusion: Our analysis reveals that, to date, there is no evidence that arthroplasty decreases ASD compared with ACDF; the promise of arthroplasty decreasing ASD has not been fulfilled. PMID:23236312

Disc degeneration: current surgical options

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C Schizas

2010-10-01

Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

A device for external γ-irradiation of experimental animals

International Nuclear Information System (INIS)

Ivanitskaya, N.F.; Talakin, Yu.N.; Lekakh, V.A.

1992-01-01

A device was developed for external gamma-irradiation of experimental animals including a radiation source, a device for fixation of the total animal or a segment of its body in the focus of irradiation, and a shilding screen. To widen the sphere of this device application by making possible a simultaneous radiation exposure of a group of animals under various radiation schedules, the device involves two discs with a common axis. The lower disc is provided with an electric drive and containers with animals are placed on it, and the upper disc is for the shielding screen. The device is supplied with an operation block

Complications of Lumbar Artificial Disc Replacement Compared to Fusion: Results From the Prospective, Randomized, Multicenter US Food and Drug Administration Investigational Device Exemption Study of the Charité Artificial Disc

Science.gov (United States)

Majd, Mohammed E.; Isaza, Jorge E.; Blumenthal, Scott L.; McAfee, Paul C.; Guyer, Richard D.; Hochschuler, Stephen H.; Geisler, Fred H.; Garcia, Rolando; Regan, John J.

2007-01-01

Background Previous reports of lumbar total disc replacement (TDR) have described significant complications. The US Food and Drug Administration (FDA) investigational device exemption (IDE) study of the Charité artificial disc represents the first level I data comparison of TDR to fusion. Methods In the prospective, randomized, multicenter IDE study, patients were randomized in a 2:1 ratio, with 205 patients in the Charité group and 99 patients in the control group (anterior lumbar interbody fusion [ALIF] with BAK cages). Inclusion criteria included confirmed single-level degenerative disc disease at L4-5 or L5-S1 and failure of nonoperative treatment for at least 6 months. Complications were reported throughout the study. Results The rate of approach-related complications was 9.8% in the investigational group and 10.1% in the control group. The rate of major neurological complications was similar between the 2 groups (investigational = 4.4%, control = 4.0%). There was a higher rate of superficial wound infection in the investigational group but no deep wound infections in either group. Pseudarthrosis occurred in 9.1% of control group patients. The rate of subsidence in the investigational group was 3.4%. The reoperation rate was 5.4% in the investigational group and 9.1% in the control group. Conclusions The incidence of perioperative and postoperative complications for lumbar TDR was similar to that of ALIF. Vigilance is necessary with respect to patient indications, training, and correct surgical technique to maintain TDR complications at the levels experienced in the IDE study. PMID:25802575

DIAM device for low back pain in degenerative disc disease : 24 months follow-up.

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Buric, Josip; Pulidori, Massimiliano; Sinan, Tariq; Mehraj, Sheikh

2011-01-01

To evaluate the usefulness of the DIAM device in patients affected by low back pain due to degenerative disc disease. Recently a number of interspinous devices for dynamic interspinous distraction-stabilization have entered the clinical practice in Europe. All of these devices have a common property of acting on the posterior part of the functional spinal unit by distracting the spinous processes and avoiding extension of the treated segment. Consequently, these systems seem to improve the cross-sectional area of the thecal sac and enlarge the diameter of the intervertebral foramina. What was found as a collateral observation after implantation of these devices was that those patients affected by low back pain, improved significantly in their pain level. Fifty-two consecutive patients were included in the study. There were 29 females and 23 males, aged between 29 and 77 years (mean 49.4 ± s.d. 12.4). The pre-operative symptom duration ranged from 6 to 84 months (mean 31.8 ± s.d. 20.2, median 24 months).The following diagnostic measures were performed in each patient: MRI, dynamic X-rays and provocative discography positive for pain reproduction.The patients were followed for pain by VAS and for functional status by self-reported Roland-Morris Disability Questionnaire. The minimum follow-up was 24 months (24-36). The intermediate follow-up at 6, 12 and 18 months was tested for, too. To determine the number of improved patients we have arbitrarily selected a cut-off criteria based on a ≥30% of improvement as calculated on the Roland Morris Disability Questionnaire scale comparing the 24 months values to the baseline values. Forty-six patients (88%) were considered as success and 2 (4%) were considered as failure. No long-term complications were observed. This preliminary report indicates that the DIAM device could possibly be useful in the treatment of LBP due to DDD. Further research with RCT is necessary to confirm these preliminary results.

A homopolar disc dynamo experiment with liquid metal contacts

OpenAIRE

Avalos-Zúñiga, R. A.; Priede, J.; Bello-Morales, C. E.

2017-01-01

We present experimental results of a homopolar disc dynamo constructed at CICATA-Quer\\'etaro in Mexico. The device consists of a flat, multi-arm spiral coil which is placed above a fast-spinning metal disc and connected to the latter by sliding liquid-metal electrical contacts. Theoretically, self-excitation of the magnetic field is expected at the critical magnetic Reynolds number Rm~45, which corresponds to a critical rotation rate of about 10 Hz. We measured the magnetic field above the di...

Floppy disc units for data collection from neutron beam experiments

International Nuclear Information System (INIS)

Hall, J.W.

1976-02-01

The replacement of paper tape output facilities on neutron beam equipment on DIDO and PLUTO reactors by floppy discs will improve reliability and provide a more manageable data storage medium. The cost of floppy disc drives is about the same as a tape punch and printer and less than other devices such as a magnetic tape. Suitable floppy disc controllers are not at present available and a unit was designed as a directly pluggable replacement for paper tape punches. This design was taken as the basis in the development of a prototype unit for use in neutron beam equipment. The circuit operation for this prototype unit is described. (author)

A novel technique for impaction bone grafting in acetabular reconstruction of revision total hip arthroplasty using an ex vivo compaction device

International Nuclear Information System (INIS)

Akiyama, Haruhiko; Takemoto, Mitsuru; Morishima, Takkan

2011-01-01

Impaction bone grafting allows restoration of the acetabular bone stock in revision hip arthroplasty. The success of this technique depends largely on achieving adequate initial stability of the component. To obtain well-compacted, well-graded allograft aggregates, we developed an ex vivo compaction device to apply it in revision total hip arthroplasty on the acetabular side, and characterized mechanical properties and putative osteoconductivity of allograft aggregates. Morselized allograft bone chips were compacted ex vivo using the creep technique and subsequent impaction technique to form the bone aggregates. Impaction allograft reconstruction of the acetabulum using an ex vivo compaction device was performed on eight hips. The mechanical properties and three-dimensional micro-CT-based structural characteristics of the bone aggregates were investigated. In clinical practice, this technique offered good reproducibility in reconstructing the cavity and the segmental defects of the acetabulum, with no migration and no loosening of the component. In vitro analysis showed that the aggregates generated from 25 g fresh-frozen bone chips gained compression stiffness of 13.5-15.4 MPa under uniaxial consolidation strain. The recoil of the aggregates after compaction was 2.6-3.9%. The compression stiffness and the recoil did not differ significantly from those measured using a variety of proportions of large- and small-sized bone chips. Micro-CT-based structural analysis revealed average pore sizes of 268-299 μm and average throat diameter of pores in the bone aggregates of more than 100 μm. These sizes are desirable for osteoconduction, although large interconnected pores of more than 500 μm were detectable in association with the proportion of large-sized bone chips. Cement penetration into the aggregates was related to the proportion of large-sized bone chips. This study introduces the value of an ex vivo compaction device in bone graft compaction in clinical

Validity of a device designed to measure braking power in bicycle disc brakes.

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Miller, Matthew C; Fink, Philip W; Macdermid, Paul William; Perry, Blake G; Stannard, Stephen R

2017-07-21

Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r 2  = 0.989; p brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists' ability to traverse through various terrains.

Stemless shoulder arthroplasty: current status.

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Churchill, R Sean

2014-09-01

Since the original Neer humeral replacement in the 1950s, the standard primary anatomic total shoulder arthroplasty design has slowly evolved. Most recently, the humeral stem has become progressively shorter to help combat stem-related complications. Currently, there are several companies who have developed and marketed a stemless humeral arthroplasty component. Manufacturers' data for 5 stemless shoulder arthroplasty components currently on the market were analyzed and reviewed. A literature review of short-term results for stemless shoulder arthroplasty was completed. Of the stemless shoulder arthroplasty systems available on the market, 3 are currently undergoing clinical trials in the United States. The Tornier Simpliciti (Tornier, Edina, MN, USA) clinical trial began in 2011. The study with 2-year minimum follow-up results is scheduled for completion in November 2014. The Arthrex Eclipse (Arthrex, Naples, FL, USA) clinical trial was started in January 2013. The tentative study completion date is 2017. The Biomet Nano (Biomet, Warsaw, IN, USA) clinical trial began in October 2013 and also has a tentative completion date of 2017. No other clinical trial is currently under way in the United States. Early results for stemless shoulder arthroplasty indicate clinical results similar to standard stemmed shoulder arthroplasty. Radiographic analysis indicates implant stability without migration or subsidence at 2- to 3-year minimum follow-up.. Several stemless shoulder arthroplasty implants are available outside the United States. Early clinical and radiographic results are promising, but well-designed clinical studies and midterm results are lacking. Three clinical trials are currently under way in the United States with initial availability for use anticipated in 2015. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Arthroplasty register for Germany

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Hagen, Anja

2009-10-01

Full Text Available Scientific background: The annual number of joint replacement operations in Germany is high. The introduction of an arthroplasty register promises an important contribution to the improvement of the quality of patient’s care. Research questions: The presented report addresses the questions on organization and functioning, benefits and cost-benefits as well as on legal, ethical and social aspects of the arthroplasty registers. Methods: A systematic literature search was conducted in September 2008 in the medical databases MEDLINE, EMBASE etc. and was complemented with a hand search. Documents describing arthroplasty registers and/or their relevance as well as papers on legal, ethical and social aspects of such registers were included in the evaluation. The most important information was extracted and analysed. Results: Data concerning 30 arthroplasty registers in 19 countries as well as one international arthroplasty register were identified. Most of the arthroplasty registers are maintained by national orthopedic societies, others by health authorities or by their cooperation. Mostly, registries are financially supported by governments and rarely by other sources.The participation of the orthopedists in the data collection process of the arthroplasty registry is voluntary in most countries. The consent of the patients is usually required. The unique patient identification is ensured in nearly all registers.Each data set consists of patient and clinic identification numbers, data on diagnosis, the performed intervention, the operation date and implanted prostheses. The use of clinical scores, patient-reported questionnaires and radiological documentation is rare. Methods for data documentation and transfer are paper form, electronic entry as well as scanning of the data using bar codes. The data are mostly being checked for their completeness and validity. Most registers offer results of the data evaluation to the treating orthopedists and

Application of TACT registered to the evaluation of total joint arthroplasty

International Nuclear Information System (INIS)

Fahey, Frederic H.; Webber, Richard L.; Chew, Felix S.-K.; Dickerson, Bryon A.

2003-01-01

Three-dimensional imaging may be valuable in the evaluation of total joint arthroplasty. The partial-volume effect and streak artifacts from the metallic components of these devices limit the applicability of computed tomography (CT) to this application. Tuned-aperture computed tomography registered (TACT registered ) is a tomographic approach that has been successfully used in other medical applications. In TACT, the acquisition geometry is inferred from the localization of fiducial markers in a series of projection images. The flexibility and robustness of TACT, as well as the fact that through an appropriate choice of reconstruction algorithms it can suppress streak artifacts, potentially makes it an appropriate approach for evaluating total joint arthroplasty. A simple computer-simulated model of a total knee replacement (TKR) was generated and used to evaluate the accuracy and artifacts associated with three-dimensional (3-D) renderings produced using TACT. A knee specimen from a cadaver that had received a TKR was used to investigate further the potential of TACT for this application. In both tests, TACT provided high-quality 3-D representations of the object. Both simple back-projection and minimum pixel back-projection were used to reconstruct the data. Minimum pixel back-projection provided high-contrast images that appeared to be relatively free of tomosynthetic artifacts. In summary, the potential of TACT in the evaluation of total joint arthroplasty was demonstrated. Future investigations will study TACT's ability to quantify the spatial relationship between the metallic components of these devices as well as TACT's ability to identify bony changes of diagnostic consequence

Design and Development of Micro-Power Generating Device for Biomedical Applications of Lab-on-a-Disc.

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Karunan Joseph

Full Text Available The development of micro-power generators for centrifugal microfluidic discs enhances the platform as a green point-of-care diagnostic system and eliminates the need for attaching external peripherals to the disc. In this work, we present micro-power generators that harvest energy from the disc's rotational movement to power biomedical applications on the disc. To implement these ideas, we developed two types of micro-power generators using piezoelectric films and an electromagnetic induction system. The piezoelectric-based generator takes advantage of the film's vibration during the disc's rotational motion, whereas the electromagnetic induction-based generator operates on the principle of current generation in stacks of coil exposed to varying magnetic flux. We have successfully demonstrated that at the spinning speed of 800 revolutions per minute (RPM the piezoelectric film-based generator is able to produce up to 24 microwatts using 6 sets of films and the magnetic induction-based generator is capable of producing up to 125 milliwatts using 6 stacks of coil. As a proof of concept, a custom made localized heating system was constructed to test the capability of the magnetic induction-based generator. The heating system was able to achieve a temperature of 58.62 °C at 2200 RPM. This development of lab-on-a-disc micro power generators preserves the portability standards and enhances the future biomedical applications of centrifugal microfluidic platforms.

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

Science.gov (United States)

Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Improving tibial component coronal alignment during total knee arthroplasty with use of a tibial planing device.

Science.gov (United States)

Patil, Shantanu; D'Lima, Darryl D; Fait, James M; Colwell, Clifford W

2007-02-01

The outcomes of knee arthroplasty have been shown to be affected by component alignment. Intramedullary and extramedullary alignment instrumentation are fairly effective for achieving the desired mean tibial component coronal alignment. However, there are outliers representing >3 degrees of varus or valgus alignment with respect to the anatomic tibial shaft axis. We measured the efficacy of a custom tibial planing device for reducing the outliers in tibial alignment. We designed a tibial planing tool in an effort to improve tibial alignment. In one cohort (100 knees), we used traditional intramedullary alignment instrumentation to make the tibial bone cut. In a second cohort (120 knees), we used intramedullary alignment instrumentation to make the cut and also used a custom tool to check the cut and to correct an inexact cut. Tibial tray alignment relative to the long axis of the tibial shaft was measured in the coronal and sagittal planes on postoperative radiographs. The target coronal alignment was 90 degrees with respect to the tibial shaft axis (with alignment). A total of 100 anteroposterior radiographs and sixty-five lateral radiographs were analyzed for the group that was treated with traditional instrumentation alone, and a total of 120 anteroposterior radiographs and fifty-five lateral radiographs were analyzed for the group that was treated with use of the custom tibial planing device. The mean coronal alignment of the tibial component was 89.5 degrees +/- 2.1 degrees in the group that was treated with traditional instrumentation alone and 89.6 degrees +/- 1.4 degrees in the group that was treated with use of the custom planing device. Although the mean coronal alignment was not significantly different, the number of outliers was substantially reduced when the custom planing device was used. All 120 components that had been aligned with use of the custom planing device were within 3 degrees of the target coronal alignment, compared with only eighty

No clinical difference between large metal-on-metal total hip arthroplasty and 28-mm-head total hip arthroplasty?

NARCIS (Netherlands)

Zijlstra, Wierd P; van den Akker-Scheek, Inge; Zee, Mark J M; van Raay, Jos J A M

2011-01-01

PURPOSE: We aimed to test the claim of greater range of motion (ROM) with large femoral head metal-on-metal total hip arthroplasty. METHODS: We compared 28-mm metal-on-polyethylene (MP) total hip arthroplasty with large femoral head metal-on-metal (MM) total hip arthroplasty in a randomised clinical

Failure of aseptic revision total knee arthroplasties.

Science.gov (United States)

Leta, Tesfaye H; Lygre, Stein Håkon L; Skredderstuen, Arne; Hallan, Geir; Furnes, Ove

2015-02-01

In Norway, the proportion of revision knee arthroplasties increased from 6.9% in 1994 to 8.5% in 2011. However, there is limited information on the epidemiology and causes of subsequent failure of revision knee arthroplasty. We therefore studied survival rate and determined the modes of failure of aseptic revision total knee arthroplasties. This study was based on 1,016 aseptic revision total knee arthroplasties reported to the Norwegian Arthroplasty Register between 1994 and 2011. Revisions done for infections were not included. Kaplan-Meier and Cox regression analyses were used to assess the survival rate and the relative risk of re-revision with all causes of re-revision as endpoint. 145 knees failed after revision total knee arthroplasty. Deep infection was the most frequent cause of re-revision (28%), followed by instability (26%), loose tibial component (17%), and pain (10%). The cumulative survival rate for revision total knee arthroplasties was 85% at 5 years, 78% at 10 years, and 71% at 15 years. Revision total knee arthroplasties with exchange of the femoral or tibial component exclusively had a higher risk of re-revision (RR = 1.7) than those with exchange of the whole prosthesis. The risk of re-revision was higher for men (RR = 2.0) and for patients aged less than 60 years (RR = 1.6). In terms of implant survival, revision of the whole implant was better than revision of 1 component only. Young age and male sex were risk factors for re-revision. Deep infection was the most frequent cause of failure of revision of aseptic total knee arthroplasties.

Placing a price on medical device innovation: the example of total knee arthroplasty.

Directory of Open Access Journals (Sweden)

Lisa G Suter

Full Text Available BACKGROUND: Total knee arthroplasty (TKA is common, effective, and cost-effective. Innovative implants promising reduced long-term failure at increased cost are under continual development. We sought to define the implant cost and performance thresholds under which innovative TKA implants are cost-effective. METHODS: We performed a cost-effectiveness analysis using a validated, published computer simulation model of knee osteoarthritis. Model inputs were derived using published literature, Medicare claims, and National Health and Nutrition Examination Survey data. We compared projected TKA implant survival, quality-adjusted life expectancy (QALE, lifetime costs, and cost-effectiveness (incremental cost-effectiveness ratios or ICERs of standard versus innovative TKA implants. We assumed innovative implants offered 5-70% decreased long-term TKA failure rates at costs 20-400% increased above standard implants. We examined the impact of patient age, comorbidity, and potential increases in short-term failure on innovative implant cost-effectiveness. RESULTS: Implants offering ≥50% decrease in long-term TKA failure at ≤50% increased cost offered ICERs <$100,000 regardless of age or baseline comorbidity. An implant offering a 20% decrease in long-term failure at 50% increased cost provided ICERs <$150,000 per QALY gained only among healthy 50-59-year-olds. Increasing short-term failure, consistent with recent device failures, reduced cost-effectiveness across all groups. Increasing the baseline likelihood of long-term TKA failure among younger, healthier and more active individuals further enhanced innovative implant cost-effectiveness among younger patients. CONCLUSIONS: Innovative implants must decrease actual TKA failure, not just radiographic wear, by 50-55% or more over standard implants to be broadly cost-effective. Comorbidity and remaining life span significantly affect innovative implant cost-effectiveness and should be considered in the

In vitro-analysis of kinematics and intradiscal pressures in cervical arthroplasty versus fusion--A biomechanical study in a sheep model with two semi-constrained prosthesis.

Science.gov (United States)

Daentzer, Dorothea; Welke, Bastian; Hurschler, Christof; Husmann, Nathalie; Jansen, Christina; Flamme, Christian Heinrich; Richter, Berna Ida

2015-03-24

As an alternative technique to arthrodesis of the cervical spine, total disc replacement (TDR) has increasingly been used with the aim of restoration of the physiological function of the treated and adjacent motions segments. The purpose of this experimental study was to analyze the kinematics of the target level as well as of the adjacent segments, and to measure the pressures in the proximal and distal disc after arthrodesis as well as after arthroplasty with two different semi-constrained types of prosthesis. Twelve cadaveric ovine cervical spines underwent polysegmental (C2-5) multidirectional flexibility testing with a sensor-guided industrial serial robot. Additionally, pressures were recorded in the proximal and distal disc. The following three conditions were tested: (1) intact specimen, (2) single-level arthrodesis C3/4, (3) single-level TDR C3/4 using the Discover® in the first six specimens and the activ® C in the other six cadavers. Statistical analysis was performed for the total range of motion (ROM), the intervertebral ROM (iROM) and the intradiscal pressures (IDP) to compare both the three different conditions as well as the two disc prosthesis among each other. The relative iROM in the target level was always lowered after fusion in the three directions of motion. In almost all cases, the relative iROM of the adjacent segments was almost always higher compared to the physiologic condition. After arthroplasty, we found increased relative iROM in the treated level in comparison to intact state in almost all cases, with relative iROM in the adjacent segments observed to be lower in almost all situations. The IDP in both adjacent discs always increased in flexion and extension after arthrodesis. In all but five cases, the IDP in each of the adjacent level was decreased below the values of the intact specimens after TDR. Overall, in none of the analyzed parameters were statistically significantly differences between both types of prostheses

Advances in Patellofemoral Arthroplasty.

Science.gov (United States)

Strickland, Sabrina M; Bird, Mackenzie L; Christ, Alexander B

2018-06-01

To describe current indications, implants, economic benefits, comparison to TKA, and functional and patient-reported outcomes of patellofemoral arthroplasty. Modern onlay implants and improved patient selection have allowed for recent improvements in short- and long-term outcomes after patellofemoral joint replacement surgery. Patellofemoral arthroplasty has become an increasingly utilized technique for the successful treatment of isolated patellofemoral arthritis. Advances in patient selection, implant design, and surgical technique have resulted in improved performance and longevity of these implants. Although short- and mid-term data for modern patellofemoral arthroplasties appear promising, further long-term clinical studies are needed to evaluate how new designs and technologies will affect patient outcomes and long-term implant performance.

Cervical artificial disc extrusion after a paragliding accident.

Science.gov (United States)

Niu, Tianyi; Hoffman, Haydn; Lu, Daniel C

2017-01-01

Cervical total disc replacement (TDR) is an established alternative to anterior cervical discectomy and fusion (ACDF) with excellent long-term outcomes and low failure rates. Cases of implant failure and migration are scarce and primarily limited to several years postoperatively. The authors report a case of anterior extrusion of a C4-C5 ProDisc-C (DePuy Synthes, West Chester, PA, USA) cervical artificial disc (CAD) 14 months after placement due to minor trauma. A 33-year-old female who had undergone C4-C5 CAD implantation presented with neck pain and spasm after experiencing a paragliding accident. A 4 mm anterior protrusion of the CAD was seen on x-ray. She underwent removal of the CAD followed by anterior fusion. Other cases of CAD extrusion in the literature are discussed and the device's durability and testing are considered. Overall, CAD extrusion is a rare event. This case is likely the result of insufficient osseous integration. Patients undergoing cervical TDR should avoid high-risk activities to prevent trauma that could compromise the disc's placement, and future design/research should focus on how to enhance osseous integration at the interface while minimizing excessive heterotopic ossification.

Centrifugally driven microfluidic disc for detection of chromosomal translocations

DEFF Research Database (Denmark)

Brøgger, Anna Line; Kwasny, Dorota; Bosco, Filippo G.

2012-01-01

and prognosis of patients. In this work we demonstrate a novel, centrifugally-driven microfluidic system for controlled manipulation of oligonucleotides and subsequent detection of chromosomal translocations. The device is fabricated in the form of a disc with capillary burst microvalves employed to control...

Mycobacterium smegmatis infection of a prosthetic total knee arthroplasty.

Science.gov (United States)

Saffo, Zaid; Ognjan, Anthony

2016-01-01

The most common organisms causing prosthetic knee joint infections are staphylococci. However, arthroplasty infections with atypical microbial pathogens, such as Mycobacteria can occur. Due to the rarity of mycobacterial prosthetic joint infections, diagnosis, treatment, and management of these atypical infections represent a clinical challenge. A 71-year old female post-operative day 40 after a left total knee arthroplasty was hospitalized secondary to left knee pain and suspected arthroplasty infection. She had failed outpatient oral antimicrobial treatment for superficial stitch abscess; and outpatient IV/Oral antimicrobials for a clinical postoperative septic bursitis. Ultimately, resection arthroplasty with operative tissue acid fast bacterial cultures demonstrated growth of the Mycobacterium smegmatis group. Post-operatively, she completed a combination course of oral doxycycline and levofloxacin and successfully completed a replacement arthroplasty with clinical and microbial resolution of the infection. To our knowledge, literature review demonstrates three case of knee arthroplasty infection caused by the Mycobacterium smegmatis group. Correspondingly, optimal surgical procedures and antimicrobial management including antimicrobial selection, treatment duration are not well defined. Presently, the best treatment options consists of two step surgical management including prosthesis hardware removal followed by extended antimicrobial therapy, followed by consideration for re-implantation arthroplasty. Our case illustrates importance of considering atypical mycobacterial infections in post-operative arthroplasty infections not responding to traditional surgical manipulations and antimicrobials. For an arthroplasty infection involving the atypical Mycobacterium smegmatis group, two step arthroplasty revision, including arthroplasty resection, with a combination of oral doxycycline and levofloxacin can lead to successful infection resolution, allowing for a

Comparing return to sport activities after short metaphyseal femoral arthroplasty with resurfacing and big femoral head arthroplasties.

Science.gov (United States)

Karampinas, Panagiotis K; Papadelis, Eustratios G; Vlamis, John A; Basiliadis, Hlias; Pneumaticos, Spiros G

2017-07-01

Young patients feel that maintaining sport activities after total hip arthroplasty constitutes an important part of their quality of life. The majority of hip surgeons allow patients to return to low-impact activities, but significant caution is advised to taking part in high-impact activities. The purpose of this study is to compare and evaluate the post-operative return to daily living habits and sport activities following short-metaphyseal hip and high functional total hip arthroplasties (resurfacing and big femoral head arthroplasties). In a study design, 48 patients (55 hips) were enrolled in three different comparative groups, one with the short-metaphyseal arthroplasties, a second with high functional resurfacing arthroplasties and a third of big femoral head arthroplasties. Each patient experienced a clinical examination and evaluated with Harris Hip Score, WOMAC, Sf-36, UCLA activity score, satisfaction VAS, anteroposterior and lateral X-rays of the hip and were followed in an outpatient setting for 2 years. Statistical analysis revealed no notable differences between the three groups regarding their demographic data however significant differences have been found between preoperative and postoperative clinical scores of each group. Also, we fail to reveal any significant differences when comparing data of all three groups at the final 2 years postoperative control regarding their clinical scores. The overall outcome of all three groups was similar, all the patients were satisfied and returned to previous level of sport activities. Short metaphyseal hip arthroplasties in young patients intending to return to previous and even high impact sport activities, similar to high functional resurfacing, big femoral head arthroplasties. Short stems with hard on hard bearing surfaces might become an alternative to standard stems and hip resurfacing.

Artroplastia total de disco cervical com prótese de Bryan: resultados clínicos e funcionais Artroplastía cervical total con prótesis de Bryan: resultados clínicos y funcionales Cervical total disc arthroplasty with Bryan disc: clinical and functional outcomes

Directory of Open Access Journals (Sweden)

Eduardo Machado de Menezes

2012-09-01

resultados buenos y excelentes, 10% satisfactorios y el 7% malos. Hubo sólo una complicación (3%, que se revirtió con artrodesis anterior. CONCLUSIONES: La artroplastia discal cervical ha demostrado ser un método seguro y eficaz para el tratamiento de casos seleccionados de hernia de disco cervical asociada a la radiculopatía y/o a compresión de la médula espinal en el corto y mediano plazo.OBJECTIVE: To evaluate results of cervical disc arthroplasty with the Bryan prosthesis for treatment of cervicobrachial pain (radiculopathy and spinal cord compression (myelopathy. METHODS: From 2002 to 2007, the CECOL surgical staff has operated 65 patients. Only 28 patients were found in 2010 to a new data collection. The pre- and post-operative evaluation was conducted using the CSOQ questionnaire (Cervical Spine Outcomes Questionnaire. Odom criteria were used only in the postoperative evaluation. Both were translated and adapted to local culture. RESULTS: There was a significant symptomatic and functional improvement in most patients. The reduction of neck pain (axial and brachial pain (radicular was similar. Odom criteria showed 82.1% good and excellent results, 10% satisfactory and 7% poor. There was only one complication (3% which was reversed with anterior arthrodesis. CONCLUSIONS: The total cervical disc arthroplasty has proved to be a safe and effective method to treat selected cases of cervical disc herniation with radiculopathy and/or myelopathy in the short and medium term.

Rapid washing of filter paper discs in a solid-phase radioimmunoassay with a constant flow washing device

International Nuclear Information System (INIS)

Kemeny, D.M.; West, F.B.

1982-01-01

A machine has been developed for the rapid washing of the cellulose filter paper discs that are used in a number of radioimmunoassays. The machine is simple in design, easy to use, and is capable of washing 96 filter paper discs simultaneously. The efficiency of the machine is demonstrated by a RAST assay for measuring IgE antibodies to the venom. Time taken to wash the discs was reduced 3-fold without loss of sensitivity or reproducibility. (Auth.)

Disc operational system

International Nuclear Information System (INIS)

Veretenov, V.Yu.; Volkov, A.I.; Gurevich, M.I.; Kozik, V.S.; Pod'yachev, E.I.; Shapiro, M.L.

1974-01-01

A disc operational system is proposed, which is based on the file structure and designed for use in a BESM-6 computer with the software system comprising a dispatcher DD-73 and a monitor 'Dubna'. The main distinguishing feature of the disc operational system is the decentralization of the file system. Each disc package is an independent file unaffected by the state of the other disc packages. The use of several disc packages is allowed. The above feature of the disc operational system makes it possible to simplify the language of communication with the system, to give the user the opportunity of controlling the file quite independently, and to simplify the maintenance of the discs by the computer personnel. One and the same disc can be simultaneously addressed by all problems in the processor (both mathematical and service). A single file, however, may be used in the recording mode by only one problem. The description presented is the instruction for users. It also describes special possibilities open to the system programmers [ru

Chronic infections in hip arthroplasties

DEFF Research Database (Denmark)

Lange, Jeppe; Troelsen, Anders; Thomsen, Reimar W

2012-01-01

Two-stage revision is regarded by many as the best treatment of chronic infection in hip arthroplasties. Some international reports, however, have advocated one-stage revision. No systematic review or meta-analysis has ever compared the risk of reinfection following one-stage and two-stage revisi......Two-stage revision is regarded by many as the best treatment of chronic infection in hip arthroplasties. Some international reports, however, have advocated one-stage revision. No systematic review or meta-analysis has ever compared the risk of reinfection following one-stage and two......-stage revisions for chronic infection in hip arthroplasties....

Kinematic evaluation of patients with total and reverse shoulder arthroplasty during rehabilitation exercises with different loads.

Science.gov (United States)

de Toledo, Joelly Mahnic; Loss, Jefferson Fagundes; Janssen, Thomas W; van der Scheer, Jan W; Alta, Tjarco D; Willems, W Jaap; Veeger, DirkJan H E J

2012-10-01

Following shoulder arthroplasty, any well-planned rehabilitation program should include muscle strengthening. However, it is not always clear how different external loads influence shoulder kinematics in patients with shoulder prostheses. The objective of this study was to describe shoulder kinematics and determine the contribution of the scapulothoracic joint to total shoulder motion of patients with total and reverse shoulder arthroplasties and of healthy individuals during rehabilitation exercises (anteflexion and elevation in the scapular plane) using different loading conditions (without external load, 1 kg and elastic resistance). Shoulder motions were measured using an electromagnetic tracking device. A force transducer was used to record force signals during loaded conditions using elastic resistance. Statistical comparisons were made using a three-way repeated-measures analysis of variance with a Bonferroni post hoc testing. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects. The same applies for loaded conditions (1 kg and elastic resistance) relative to unloaded tasks. For scapular internal rotation, upward rotation and posterior tilt no significant differences among groups were found during both exercises. Glenohumeral elevation angles during anteflexion were significantly higher in the total shoulder arthroplasty group compared to the reverse shoulder arthroplasty group. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant. However, compared to healthy subjects, they were. Furthermore, scapular kinematics of patients with shoulder arthroplasty was influenced by implementation of external loads, but not by the type of load. Copyright © 2012 Elsevier Ltd. All rights reserved.

Transfemoral amputation after failure of knee arthroplasty

DEFF Research Database (Denmark)

Gottfriedsen, Tinne B; Morville Schrøder, Henrik; Odgaard, Anders

2016-01-01

BACKGROUND: Transfemoral amputation is considered the last treatment option for failed knee arthroplasty. The extent to which this procedure is performed is not well known. The purpose of this study was to identify the incidence and causes of amputation following failure of knee arthroplasty...... were followed by amputation. Hospital records of all identified cases were reviewed. A competing-risk model was used to estimate the cumulative incidence of amputation. Differences in cumulative incidences were analyzed with use of the Gray test. RESULTS: A total of 115 amputations were performed...... for causes related to failed knee arthroplasty. The 15-year cumulative incidence of amputation was 0.32% (95% confidence interval [CI], 0.23% to 0.48%). The annual incidence of amputation following arthroplasties performed from 1997 to 2002 was 0.025% compared with 0.018% following arthroplasties performed...

Knee Arthrodesis After Failure of Knee Arthroplasty

DEFF Research Database (Denmark)

Gottfriedsen, Tinne B; Morville Schrøder, Henrik; Odgaard, Anders

2016-01-01

BACKGROUND: Arthrodesis is considered a salvage procedure after failure of a knee arthroplasty. Data on the use of this procedure are limited. The purpose of this study was to identify the incidence, causes, surgical techniques, and outcomes of arthrodesis after failed knee arthroplasty...... in a nationwide population. METHODS: Data were extracted from the Danish Civil Registration System, the Danish National Patient Register, and the Danish Knee Arthroplasty Register. A total of 92,785 primary knee arthroplasties performed in Denmark from 1997 to 2013 were identified by linking the data using....... Differences in cumulative incidence were compared with the Gray test. RESULTS: A total of 164 of the 165 arthrodeses were performed for causes related to failed knee arthroplasty. The 15-year cumulative incidence of arthrodesis was 0.26% (95% confidence interval, 0.21% to 0.31%). The 5-year cumulative...

Return to sports after shoulder arthroplasty

Science.gov (United States)

Johnson, Christine C; Johnson, Daniel J; Liu, Joseph N; Dines, Joshua S; Dines, David M; Gulotta, Lawrence V; Garcia, Grant H

2016-01-01

Many patients prioritize the ability to return to sports following shoulder replacement surgeries, including total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RTSA), and hemiarthroplasty (HA). While activity levels after hip and knee replacements have been well-established in the literature, studies on this topic in the field of shoulder arthroplasty are relatively limited. A review of the literature regarding athletic activity after shoulder arthroplasty was performed using the PubMed database. All studies relevant to shoulder arthroplasty and return to sport were included. The majority of patients returned to their prior level of activity within six months following TSA, RTSA, and shoulder HA. Noncontact, low demand activities are permitted by most surgeons postoperatively and generally have higher return rates than contact sports or high-demand activities. In some series, patients reported an improvement in their ability to participate in sports following the arthroplasty procedure. The rates of return to sports following TSA (75%-100%) are slightly higher than those reported for HA (67%-76%) and RTSA (75%-85%). Patients undergoing TSA, RTSA, and shoulder HA should be counseled that there is a high probability that they will be able to return to their preoperative activity level within six months postoperatively. TSA has been associated with higher rates of return to sports than RTSA and HA, although this may reflect differences in patient population or surgical indication. PMID:27672564

Biomechanical evaluation of a spherical lumbar interbody device at varying levels of subsidence.

Science.gov (United States)

Rundell, Steven A; Isaza, Jorge E; Kurtz, Steven M

2011-01-01

Ulf Fernström implanted stainless steel ball bearings following discectomy, or for painful disc disease, and termed this procedure disc arthroplasty. Today, spherical interbody spacers are clinically available, but there is a paucity of associated biomechanical testing. The primary objective of the current study was to evaluate the biomechanics of a spherical interbody implant. It was hypothesized that implantation of a spherical interbody implant, with combined subsidence into the vertebral bodies, would result in similar ranges of motion (RoM) and facet contact forces (FCFs) when compared with an intact condition. A secondary objective of this study was to determine the effect of using a polyetheretherketone (PEEK) versus a cobalt chrome (CoCr) implant on vertebral body strains. We hypothesized that the material selection would have a negligible effect on vertebral body strains since both materials have elastic moduli substantially greater than the annulus. A finite element model of L3-L4 was created and validated by use of ROM, disc pressure, and bony strain from previously published data. Virtual implantation of a spherical interbody device was performed with 0, 2, and 4 mm of subsidence. The model was exercised in compression, flexion, extension, axial rotation, and lateral bending. The ROM, vertebral body effective (von Mises) strain, and FCFs were reported. Implantation of a PEEK implant resulted in slightly lower strain maxima when compared with a CoCr implant. For both materials, the peak strain experienced by the underlying bone was reduced with increasing subsidence. All levels of subsidence resulted in ROM and FCFs similar to the intact model. The results suggest that a simple spherical implant design is able to maintain segmental ROM and provide minimal differences in FCFs. Large areas of von Mises strain maxima were generated in the bone adjacent to the implant regardless of whether the implant was PEEK or CoCr.

Effect of prosthesis endplate lordosis angles on L5-S1 kinematics after disc arthroplasty.

Science.gov (United States)

Tsitsopoulos, Parmenion P; Wojewnik, Bartosz; Voronov, Leonard I; Havey, Robert M; Renner, Susan M; Zelenakova, Julia; McIntosh, Braden; Carandang, Gerard; Abjornson, Celeste; Patwardhan, Avinash G

2012-06-01

We hypothesized that L5-S1 kinematics will not be affected by the lordosis distribution between the prosthesis endplates. Twelve cadaveric lumbosacral spines (51.3 ± 9.8 years) were implanted with 6° or 11° prostheses (ProDisc-L) with four combinations of superior/inferior lordosis (6°/0°, 3°/3°, 11°/0°, 3°/8°). Specimens were tested intact and after prostheses implantation with different lordosis distributions. Center of rotation (COR) and range of motion (ROM) were quantified. Six-degree lordosis prostheses (n = 7) showed no difference in flexion-extension ROM, regardless of design (6°/0° or 3°/3°) (p > 0.05). In lateral bending (LB), both designs reduced ROM (p lordosis prostheses (n = 5) showed no difference in flexion-extension ROM for either design (p > 0.05). LB ROM decreased with distributed lordosis prostheses (3°/8°) (p lordosis distribution among the two prosthesis endplates. The ProDisc-L prosthesis design where all lordosis is concentrated in the superior endplate yielded COR locations that were anterior and caudal to intact controls. The prosthesis with lordosis distributed between the two endplates yielded a COR that tended to be closer to intact. Further clinical and biomechanical studies are needed to assess the long-term impact of lordosis angle distribution on the fate of the facet joints.

Status of prototype rupture disc testing in the large leak test rig

International Nuclear Information System (INIS)

Amos, J.C.

1979-09-01

The prototype CRBRP double membrane rupture disc assembly is being performance tested in conjunction with the LLTR Series II Large Leak Program. In May 1979, the double membrane disc assembly was inadvertently activated during sodium system pressure instrument calibration. This experience indicated that the rupture disc burst at essentially the design burst pressure when a gradually increasing state pressure was applied. The area of membrane opening was found to be about 25 to 30% of the cross-sectional area. In July 1979, the disc assembly was again tested (this time in a single membrane configuration) in conjunction with the first LLTR Series II Test A-1a (inert gas injection). Test data indicated that the disc burst in about 35 ms at essentially the design burst pressure with an opening of about 30% of the cross-sectional area. The pressure immediately downstream of the disc dropped below atmospheric pressure following the rupture tube event (releasing high pressure nitrogen into sodium) for about 1.5 seconds before increasing to a maximum of 30 psig. This behavior raises a question on the adequacy of a downstream pressure device for rapid sensing of disc rupture and initiating plant shutdown following a large SWR event. 14 figures

An evaluation of information on the Internet of a new device: the lumbar artificial disc replacement.

Science.gov (United States)

Garcia, Ryan M; Messerschmitt, Patrick J; Ahn, Nicholas U

2009-02-01

An analysis of websites, accessible to the public, was conducted pertaining to the lumbar artificial disc replacement. The objective was to investigate the content of information available on the Internet pertaining to the lumbar artificial disc replacement. The Internet is widely used by patients as an educational tool for health care information. Additionally, the Internet is used as a medium for direct-to-consumer marketing. Recent approval of the lumbar artificial disc replacement has led to the emergence of numerous websites offering information about this procedure. It is thought that patients can be influenced by information found on the Internet; therefore, it is imperative that this information be accurate and as complete as possible. Three commonly used search engines were used to locate 105 (35/search engine) websites providing information about the lumbar artificial disc replacement. Each website was evaluated with regard to authorship and content. Fifty-nine percent of the websites reviewed were authorized by a private physician group, 9% by an academic physician group, 6% by industry, 11% were news reports, and 15% were not otherwise categorized. Seventy-two percent offered a mechanism for direct contact and 30% provided clear patient selection criteria. Benefits were expressed in 87% of websites, whereas associated risks were described in 28% or less. European experiences were noted in 53%, whereas only 22% of websites detailed the current US experience. The results of this study demonstrate that much of the content of Internet-derived information pertaining to the lumbar artificial disc replacement is potentially misleading. Until long-term data are available, patients should be cautioned when using the Internet as a source for health care information, particularly with regard to the lumbar artificial disc replacement.

Imaging of hip arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Miller, Theodore T., E-mail: millertt@hss.edu [Department of Radiology and Imaging, Hospital for Special Surgery, 535 E. 70th Street, New York, NY 10021 (United States)

2012-12-15

The imaging evaluation of the prosthetic hip begins with radiography, but arthrography, aspiration, scintigraphy, sonography, CT and MR imaging all have roles in the evaluation of the painful prosthesis. This article will review the appearance of normal hip arthroplasty including hemiarthroplasty, total arthroplasty, and hip resurfacing, as well as the appearances of potential complications such as aseptic loosening and osteolysis, dislocation, infection, periprosthetic fracture, hardware failure, and soft tissue abnormalities.

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Science.gov (United States)

2010-01-01

Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty

Directory of Open Access Journals (Sweden)

Denkena Berend

2010-06-01

Full Text Available Abstract Background Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. Methods A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. Results The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. Conclusions The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in

A rolling-gliding wear simulator for the investigation of tribological material pairings for application in total knee arthroplasty.

Science.gov (United States)

Richter, Berna I; Ostermeier, Sven; Turger, Anke; Denkena, Berend; Hurschler, Christof

2010-06-15

Material wear testing is an important technique in the development and evaluation of materials for use in implant for total knee arthroplasty. Since a knee joint induces a complex rolling-gliding movement, standardised material wear testing devices such as Pin-on-Disc or Ring-on-Disc testers are suitable to only a limited extent because they generate pure gliding motion only. A rolling-gliding wear simulator was thus designed, constructed and implemented, which simulates and reproduces the rolling-gliding movement and loading of the knee joint on specimens of simplified geometry. The technical concept was to run a base-plate, representing the tibia plateau, against a pivoted cylindrical counter-body, representing one femur condyle under an axial load. A rolling movement occurs as a result of the friction and pure gliding is induced by limiting the rotation of the cylindrical counter-body. The set up also enables simplified specimens handling and removal for gravimetrical wear measurements. Long-term wear tests and gravimetrical wear measurements were carried out on the well known material pairings: cobalt chrome-polyethylene, ceramic-polyethylene and ceramic-ceramic, over three million motion cycles to allow material comparisons to be made. The observed differences in wear rates between cobalt-chrome on polyethylene and ceramic on polyethylene pairings were similar to the differences of published data for existing material-pairings. Test results on ceramic-ceramic pairings of different frontal-plane geometry and surface roughness displayed low wear rates and no fracture failures. The presented set up is able to simulate the rolling-gliding movement of the knee joint, is easy to use, and requires a minimum of user intervention or monitoring. It is suitable for long-term testing, and therefore a useful tool for the investigation of new and promising materials which are of interest for application in knee joint replacement implants.

Clinical outcome after treatment of infected primary total knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik; Jensen, Tim Toftgaard

2002-01-01

Twenty-six consecutive cases of infected primary total knee arthroplasties were treated at our institution from 1989 through 2000. Eleven patients had debridement and irrigation performed within 2 months of index arthroplasty or hematogenous spread; only one infection was eradicated. Twenty......-five patients had their prostheses removed; 17 had two-stage revision arthroplasty, following which infection was eradicated in 15; one had a permanent spacer, 7 had arthrodesis (following failed revision arthroplasty in one) and 2 had a femur amputation (following failed revision arthroplasty in one) at follow......-up of mean 24 months. Infections were cured equally well with revision arthroplasty and arthrodesis. Among the 15 patients who ended up with revision arthroplasty, 11 had a better range of motion compared to the index arthroplasty, but 8 had daily pain. We present our treatment protocol, which eradicated 15...

One-stage versus two-stage exchange arthroplasty for infected total knee arthroplasty: a systematic review.

Science.gov (United States)

Nagra, Navraj S; Hamilton, Thomas W; Ganatra, Sameer; Murray, David W; Pandit, Hemant

2016-10-01

Infection complicating total knee arthroplasty (TKA) has serious implications. Traditionally the debate on whether one- or two-stage exchange arthroplasty is the optimum management of infected TKA has favoured two-stage procedures; however, a paradigm shift in opinion is emerging. This study aimed to establish whether current evidence supports one-stage revision for managing infected TKA based on reinfection rates and functional outcomes post-surgery. MEDLINE/PubMed and CENTRAL databases were reviewed for studies that compared one- and two-stage exchange arthroplasty TKA in more than ten patients with a minimum 2-year follow-up. From an initial sample of 796, five cohort studies with a total of 231 patients (46 single-stage/185 two-stage; median patient age 66 years, range 61-71 years) met inclusion criteria. Overall, there were no significant differences in risk of reinfection following one- or two-stage exchange arthroplasty (OR -0.06, 95 % confidence interval -0.13, 0.01). Subgroup analysis revealed that in studies published since 2000, one-stage procedures have a significantly lower reinfection rate. One study investigated functional outcomes and reported that one-stage surgery was associated with superior functional outcomes. Scarcity of data, inconsistent study designs, surgical technique and antibiotic regime disparities limit recommendations that can be made. Recent studies suggest one-stage exchange arthroplasty may provide superior outcomes, including lower reinfection rates and superior function, in select patients. Clinically, for some patients, one-stage exchange arthroplasty may represent optimum treatment; however, patient selection criteria and key components of surgical and post-operative anti-microbial management remain to be defined. III.

New Universal Tribometer as Pin or Ball-on-Disc and Reciprocating Pin-on-Plate Types

Directory of Open Access Journals (Sweden)

H. Kaleli

2016-06-01

Full Text Available The present paper contains a description of a new Universal Tribometer design which enables simulation of different contact and test types such as pin-on-disc, ball-on-disc and linear reciprocating tests. There are many models of wear Tribometer in the world market. These devices are manufactured by various companies abroad and are imported to our country. Cost of this devices start from 50.000 euros and goes to hundreds of thousands of euros. One of the most commonly used of this device is Reciprocating Pin-on-Plate Tribo Test Machine. This wear tester is produced at a low limited cost within the KAP (Scientifical Research Project Coordinator of Yıldız Technical University. The test machine can work including three types of Tribotest rigs (Reciprocating Pin-on-Plate, Pin-on-Disc and Ball-on-Disc. It is designed to operate also at high temperatures up to 500 ˚C. The new piece of equipment allows instrumented tribological testing of piston ring and cylinder liner samples at low and high temperatures and boundary lubrication conditions of any typical gasoline or Diesel engines. Some friction results were shown in boundary lubricating conditions between piston ring and cylinder liner sliding pairs describing Tribotest machine is driven by AC servo motor which is more accurate than DC motor.

Robotics in Arthroplasty: A Comprehensive Review.

Science.gov (United States)

Jacofsky, David J; Allen, Mark

2016-10-01

Robotic-assisted orthopedic surgery has been available clinically in some form for over 2 decades, claiming to improve total joint arthroplasty by enhancing the surgeon's ability to reproduce alignment and therefore better restore normal kinematics. Various current systems include a robotic arm, robotic-guided cutting jigs, and robotic milling systems with a diversity of different navigation strategies using active, semiactive, or passive control systems. Semiactive systems have become dominant, providing a haptic window through which the surgeon is able to consistently prepare an arthroplasty based on preoperative planning. A review of previous designs and clinical studies demonstrate that these robotic systems decrease variability and increase precision, primarily focusing on component positioning and alignment. Some early clinical results indicate decreased revision rates and improved patient satisfaction with robotic-assisted arthroplasty. The future design objectives include precise planning and even further improved consistent intraoperative execution. Despite this cautious optimism, many still wonder whether robotics will ultimately increase cost and operative time without objectively improving outcomes. Over the long term, every industry that has seen robotic technology be introduced, ultimately has shown an increase in production capacity, improved accuracy and precision, and lower cost. A new generation of robotic systems is now being introduced into the arthroplasty arena, and early results with unicompartmental knee arthroplasty and total hip arthroplasty have demonstrated improved accuracy of placement, improved satisfaction, and reduced complications. Further studies are needed to confirm the cost effectiveness of these technologies. Copyright © 2016 Elsevier Inc. All rights reserved.

Utility of noninvasive transcutaneous measurement of postoperative hemoglobin in total joint arthroplasty patients.

Science.gov (United States)

Stoesz, Michael; Wood, Kristin; Clark, Wesley; Kwon, Young-Min; Freiberg, Andrew A

2014-11-01

This study prospectively evaluated the clinical utility of a noninvasive transcutaneous device for postoperative hemoglobin measurement in 100 total hip and knee arthroplasty patients. A protocol to measure hemoglobin noninvasively, prior to venipuncture, successfully avoided venipuncture in 73% of patients. In the remaining 27 patients, there were a total of 48 venipunctures performed during the postoperative hospitalization period due to reasons including transcutaneous hemoglobin measurement less than or equal to 9 g/dL (19), inability to obtain a transcutaneous hemoglobin measurement (8), clinical signs of anemia (3), and noncompliance with the study protocol (18). Such screening protocols may provide a convenient and cost-effective alternative to routine venipuncture for identifying patients at risk for blood transfusion after elective joint arthroplasty. Copyright © 2014 Elsevier Inc. All rights reserved.

Imaging of knee arthroplasty

International Nuclear Information System (INIS)

Miller, Theodore T.

2005-01-01

Knee replacement surgery, either with unicompartmental or total systems, is common. The purpose of this manuscript is to review the appearance of normal knee arthroplasty and the appearances of complications such as infection, polyethylene wear, aseptic loosening and particle-induced osteolysis, patellofemoral abnormalities, axial instability, and periprosthetic and component fracture. Knowledge of the potential complications and their imaging appearances will help the radiologist in the diagnostic evaluation of the patient with a painful knee arthroplasty

Imaging of knee arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Miller, Theodore T. [Department of Radiology, North Shore University Hospital, 825 Northern Blvd., Great Neck, NY 11021 (United States)]. E-mail: TMiller@NSHS.edu

2005-05-01

Knee replacement surgery, either with unicompartmental or total systems, is common. The purpose of this manuscript is to review the appearance of normal knee arthroplasty and the appearances of complications such as infection, polyethylene wear, aseptic loosening and particle-induced osteolysis, patellofemoral abnormalities, axial instability, and periprosthetic and component fracture. Knowledge of the potential complications and their imaging appearances will help the radiologist in the diagnostic evaluation of the patient with a painful knee arthroplasty.

Heterotopic ossification associated with myelopathy following cervical disc prosthesis implantation.

Science.gov (United States)

Wenger, Markus; Markwalder, Thomas-Marc

2016-04-01

This case report presents a 37-year-old man with clinical signs of myelopathy almost 9 years after implantation of a Bryan disc prosthesis (Medtronic Sofamor Danek, Memphis, TN, USA) for C5/C6 soft disc herniation. As demonstrated on MRI and CT scan, spinal cord compression was caused by bony spurs due to heterotopic ossification posterior to the still moving prosthesis. The device, as well as the ectopic bone deposits, had to be removed because of myelopathy and its imminent aggravation. Conversion to anterior spondylodesis was performed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hip Resurfacing Arthroplasty and Perioperative Blood Testing

Directory of Open Access Journals (Sweden)

Andrew Cook

2014-01-01

Full Text Available It is standard practice in many institutions to routinely perform preoperative and postoperative haemoglobin level testing in association with hip joint arthroplasty procedures. It is our observation, however, that blood transfusion after uncomplicated primary hip arthroplasty in healthy patients is uncommon and that the decision to proceed with blood transfusion is typically made on clinical grounds. We therefore question the necessity and clinical value of routine perioperative blood testing about the time of hip resurfacing arthroplasty. We present analysis of perioperative blood tests and transfusion rates in 107 patients undertaking unilateral hybrid hip resurfacing arthroplasty by the senior author at a single institution over a three-year period. We conclude that routine perioperative testing of haemoglobin levels for hip resurfacing arthroplasty procedures does not assist in clinical management. We recommend that postoperative blood testing only be considered should the patient demonstrate clinical signs of symptomatic anaemia or if particular clinical circumstances necessitate.

Total hip arthroplasty in Denmark

DEFF Research Database (Denmark)

Pedersen, Alma Becic; Johnsen, Søren Paaske; Overgaard, Søren

2005-01-01

The annual number of total hip arthroplasties (THA) has increased in Denmark over the past 15 years. There is, however, limited detailed data available on the incidence of THAs.......The annual number of total hip arthroplasties (THA) has increased in Denmark over the past 15 years. There is, however, limited detailed data available on the incidence of THAs....

Star-disc interaction in galactic nuclei: formation of a central stellar disc

Science.gov (United States)

Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

2018-05-01

We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

Hip arthroplasty in failed intertrochanteric fractures in elderly

Directory of Open Access Journals (Sweden)

Javahir A Pachore

2013-01-01

Full Text Available Background: Failed intertrochanteric fractures in elderly patients are surgical challenge with limited options. Hip arthroplasty is a good salvage procedure even though it involves technical issues such as implant removal, bone loss, poor bone quality, trochanteric nonunion and difficulty of surgical exposure. Materials and Methods: 30 patients of failed intertrochanteric fractures where hip arthroplasty was done between May 2008 and December 2011 were included in study. 13 were males and 17 were females with average age of 67.3 years. There were 2 cemented bipolar arthroplasties, 19 uncemented bipolar, 4 cemented total hip arthroplasty and 5 uncemented total hip arthroplasties. 16 patients had a trochanteric nonunion, which was treated by tension band principles. Total hip was considered where there was acetabular damage due to the penetration of implant. Results: The average followup was 20 months (range 6-48 months. Patients were followed up from 6 to 48 months with average followup of 20 months. None of the patients were lost to followup. There was no dislocation. All patients were ambulatory at the final followup. Conclusion: A predictable functional outcome can be achieved by hip arthroplasty in elderly patients with failed intertrochanteric fractures. Though technically demanding, properly performed hip arthroplasty can be a good salvage option for this patient group.

Long-term outcomes of patellofemoral arthroplasty.

NARCIS (Netherlands)

Jonbergen, J.P.W. van; Werkman, D.M.; Barnaart, L.F.; Kampen, A. van

2010-01-01

The purpose of this study was to correlate the long-term survival of patellofemoral arthroplasty with primary diagnosis, age, sex, and body mass index. One hundred eighty-five consecutive Richards type II patellofemoral arthroplasties were performed in 161 patients with isolated patellofemoral

A protocol avoiding allogeneic transfusion in joint arthroplasties.

Science.gov (United States)

Suh, You-Sung; Nho, Jae-Hwi; Choi, Hyung-Suk; Ha, Yong-Chan; Park, Jong-Seok; Koo, Kyung-Hoi

2016-09-01

Arthroplasties of hip and knee are associated with blood loss, which may lead to adverse patient outcome. Performing arthroplasties in Jehovah's Witness patients who do not accept transfusion has been a matter of concern. We developed a protocol, which avoids transfusion in arthroplasties of Jehovah's Witness patients, and evaluated the feasibility and safety of the protocol. The target of preoperative hemoglobin was more than 10 g/dL. When preoperative hemoglobin was lower than 10 g/dL, 4000 U erythropoietin (3 times a week) and 100 mg iron supplement (every day) were administered until the hemoglobin reached 10 g/dL. When the preoperative hemoglobin was higher than 10 g/dL, 4000 U erythropoietin and 100 mg iron supplement were administered once, before operation. During the operation, cell saver was used. Postoperatively, erythropoietin and iron supplements were administered until the hemoglobin reached 10 g/dL, similar to the preoperative protocol. We evaluated the feasibility of our protocol, perioperative complications and hematologic changes. From 2002 to 2014, 186 Witness patients visited our department. In 179 patients (96.2 %), 77 total knee arthroplasties, 69 bipolar hemiarthroplasties and 33 total hip arthroplasties were performed. The mean hemoglobin level was 12.3 g/dL preoperatively, 9.4 g/dL on postoperative day 3 and 10.3 g/dL on postoperative day 7. One patient died immediately after the arthroplasty and the remaining 178 patients survived. Total joint arthroplasty could be done without transfusion using this protocol in most of our patients. The rates of infection and mortality were similar with known infection and mortality rates of arthroplasties. In patients who do not want allogeneic transfusions, our protocol is a safe alternative to perform joint arthroplasties.

Cryotherapy on postoperative rehabilitation of joint arthroplasty.

Science.gov (United States)

Ni, Sheng-Hui; Jiang, Wen-Tong; Guo, Lei; Jin, Yu-Heng; Jiang, Tian-Long; Zhao, Yuyan; Zhao, Jie

2015-11-01

The effectiveness of cryotherapy on joint arthroplasty recovery remains controversial. This systematic review was conducted to assess the effectiveness of cryotherapy in patients after joint arthroplasty. Comprehensive literature searches of several databases including Cochrane Library (2013), MEDLINE (1950-2013), and Embase (1980-2013) were performed. We sought randomised controlled trials that compared the experimental group received any form of cryotherapy with any control group after joint arthroplasty. The main outcomes were postoperative blood loss, adverse events, and pain. Analyses were performed with Revman 5.0. Results were shown as mean differences (MD) and standard deviations or as risk difference and 95 % confidence intervals (CIs). Ten trials comprised 660 total knee arthroplastys and three trials comprised 122 total hip arthroplastys (THAs) met the inclusion criteria. Blood loss was significantly decreased by cryotherapy (MD = -109.68; 95 % CI -210.92 to -8.44; P = 0.03). Cryotherapy did not increase the risk of adverse effect (n.s.). Cryotherapy decreased pain at the second day of postoperative (MD = -1.32; 95 % CI -2.37 to -0.27; P = 0.0003), but did not decreased pain at the first and third day of postoperative (n.s.). Cryotherapy appears effective in these selected patients after joint arthroplasty. The benefits of cryotherapy on blood loss after joint arthroplasty were obvious. However, the subgroup analysis indicated that cryotherapy did not decreased blood loss after THA. Cryotherapy did not increase the risk of adverse effect. Cryotherapy decreased pain at the second day of postoperative, but did not decreased pain at the first and third day of postoperative. II.

Automated assembly of microfluidic "lab-on-a-disc"

Science.gov (United States)

Berger, M.; Müller, T.; Voebel, T.; Baum, C.; Glennon, T.; Mishra, R.; Kinahan, D.; King, D.; Ducrée, J.; Brecher, C.

2018-02-01

Point-of-care (POC) testing attracts more and more attention in the medical health sector because of their specific property to perform the diagnostic close to the patient. The fast diagnosis right at the hospital or the doctor's office improves the medical reaction time and the chances for a successful healing process. One of this POC test systems is a "Lab-on-a-Disc" (LoaD) which looks like a compact disc crisscrossed with microfluidic tubes and cavities. The fluid to be analysed is placed in the LoaD and an external device then rotates the LoaD. The cavities inside the LoaD and the centrifugal force ensure a clearly defined sequence of the analysis. Furthermore, we aim for an inexpensive manufacture of the medical product without neglecting its quality and functionality. Therefore, the Fraunhofer IPT works on an assembly cell to implement dissoluble films concisely into the disc. This dissoluble film demonstrates its successful usage as a gate for the fluid, which opens after a predefined moment in the cycle. Furthermore, we investigate to integrate a laser welding process into our gantry system and demonstrate its efficiency with the welding of polymer discs. This procedure is clinically safe because no further laser absorption material is needed in the sealing process, which might pollute the LoaD. Moreover, this process allows the alignment of several discs before the welding and therefore leads to precisely manufactured LoaDs in large quantities. All these methods together enable a fast, costefficient and reliable mass production to bring POC testing among the people.

Comparison of radiographic changes after ACDF versus Bryan disc arthroplasty in single and bi-level cases

Science.gov (United States)

Limson, Marc Anthony; Kim, Soo-Bum; Arbatin, Jose Joefrey F.; Chang, Kee-Young; Park, Moon-Soo; Shin, Jae-hyuk; Ju, Yeong-Su

2009-01-01

The object of this study is to compare radiographic outcomes of anterior cervical decompression and fusion (ACDF) versus cervical disc replacement using the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN) in terms of range of motion (ROM), Functional spinal unit (FSU), overall sagittal alignment (C2–C7), anterior intervertebral height (AIH), posterior intervertebral height (PIH) and radiographic changes at the implanted and adjacent levels. The study consisted of 105 patients. A total of 63 Bryan disc were placed in 51 patients. A single level procedure was performed in 39 patients and a two-level procedure in the other 12. Fifty-four patients underwent ACDF, 26 single level cases and 28 double level cases. The Bryan group had a mean follow-up 19 months (12–38). Mean follow-up for the ACDF group was 20 months (12–40 months). All patients were evaluated using static and dynamic cervical spine radiographs as well as MR imaging. All patients underwent anterior cervical discectomy followed by autogenous bone graft with plate (or implantation of a cage) or the Bryan artificial disc prosthesis. Clinical evaluation included the visual analogue scale (VAS), and neck disability index (NDI). Radiographic evaluation included static and dynamic flexion-extension radiographs using the computer software (Infinitt PiviewSTAR 5051) program. ROM, disc space angle, intervertebral height were measured at the operative site and adjacent levels. FSU and overall sagittal alignment (C2–C7) were also measured pre-operatively, postoperatively and at final follow-up. Radiological change was analyzed using χ2 test (95% confidence interval). Other data were analyzed using the mixed model (SAS enterprises guide 4.1 versions). There was clinical improvement within each group in terms of VAS and NDI scores from pre-op to final follow-up but not significantly between the two groups for both single (VAS p = 0.8371, NDI p = 0.2872) and double (VAS p = 0

Lumbar disc arthroplasty: indications, biomechanics, types, and radiological criteria; Lumbale Bandscheibenendoprothesen: Indikationen, Biomechanik, Typen und radiologische Kriterien

Energy Technology Data Exchange (ETDEWEB)

Baur-Melnyk, A; Reiser, M F [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Orthopaedische Klinik und Poliklinik, Muenchen (Germany); Birkenmaier, C [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)

2006-09-15

Lumbar total disc replacement (TDR) was developed to treat a painful degenerative lumbar motion segment while avoiding the disadvantages of fusion surgery, such as adjacent segment instabilities. Early clinical results with TDR have shown a significant reduction in low back pain and a significant improvement in disability scores. When compared to fusion, the results with TDR tend to be superior in the short-term follow-up and initial rehabilitation is faster. The radiological assessment is an integral part of the preoperative work-up. Plain X-rays of the lumbar spine should be complemented by flexion - extension views in order to assess residual segmental mobility. Computed tomography is used to exclude osteoarthritis of the zygapophyseal joints, Baastrup's disease (kissing spines) and other sources of low back pain. Magnetic resonance imaging is useful to exclude substantial disc protrusions; it allows for the detection of disc dehydration and bone marrow edema in the case of activated spondylochondrosis. If osteoporosis is suspected, an osteodensitometry of the lumbar spine should be performed. Postoperative plain X-rays should include antero-posterior and lateral views as well as flexion - extension views in the later postoperative course. Measurements should determine the disc space height in the lateral view, the segmental and total lumbar lordosis as well as the segmental mobility in the flexion - extension views. The ideal position of a TDR is exactly central in the ap-view and close to the dorsal border of the vertebral endplates in the lateral view. Malpositioning may cause segmental hyperlordosis and unbalanced loading of the endplates with the risk of implant subsidence and migration. (orig.) [German] Die lumbale Bandscheibenendoprothese (LBEP) wurde entwickelt, um ein schmerzhaftes lumbales Bewegungssegment unter Vermeidung der Nachteile einer Fusionsoperation zu behandeln. Erste klinische Ergebnisse der LBEP zeigen eine signifikante Reduktion der

Lumbar disc arthroplasty: indications, biomechanics, types, and radiological criteria; Lumbale Bandscheibenendoprothesen: Indikationen, Biomechanik, Typen und radiologische Kriterien

Energy Technology Data Exchange (ETDEWEB)

Baur-Melnyk, A.; Reiser, M.F. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Orthopaedische Klinik und Poliklinik, Muenchen (Germany); Birkenmaier, C. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet, Institut fuer Klinische Radiologie, Muenchen (Germany)

2006-09-15

Lumbar total disc replacement (TDR) was developed to treat a painful degenerative lumbar motion segment while avoiding the disadvantages of fusion surgery, such as adjacent segment instabilities. Early clinical results with TDR have shown a significant reduction in low back pain and a significant improvement in disability scores. When compared to fusion, the results with TDR tend to be superior in the short-term follow-up and initial rehabilitation is faster. The radiological assessment is an integral part of the preoperative work-up. Plain X-rays of the lumbar spine should be complemented by flexion - extension views in order to assess residual segmental mobility. Computed tomography is used to exclude osteoarthritis of the zygapophyseal joints, Baastrup's disease (kissing spines) and other sources of low back pain. Magnetic resonance imaging is useful to exclude substantial disc protrusions; it allows for the detection of disc dehydration and bone marrow edema in the case of activated spondylochondrosis. If osteoporosis is suspected, an osteodensitometry of the lumbar spine should be performed. Postoperative plain X-rays should include antero-posterior and lateral views as well as flexion - extension views in the later postoperative course. Measurements should determine the disc space height in the lateral view, the segmental and total lumbar lordosis as well as the segmental mobility in the flexion - extension views. The ideal position of a TDR is exactly central in the ap-view and close to the dorsal border of the vertebral endplates in the lateral view. Malpositioning may cause segmental hyperlordosis and unbalanced loading of the endplates with the risk of implant subsidence and migration. (orig.) [German] Die lumbale Bandscheibenendoprothese (LBEP) wurde entwickelt, um ein schmerzhaftes lumbales Bewegungssegment unter Vermeidung der Nachteile einer Fusionsoperation zu behandeln. Erste klinische Ergebnisse der LBEP zeigen eine signifikante Reduktion der

MR imaging findings of a sequestered disc in the lumbar spine: a comparison with an extruded disc

International Nuclear Information System (INIS)

Sim, Su Youn; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook

2007-01-01

To compare the MR findings of a sequestered disc with an extruded disc. MR images of 28 patients with a sequestered disc and 18 patients with an extruded disc were retrospectively reviewed. Patients with sequestered discs were divided into two groups whether definite separation from the parent disc was or was not seen. In the latter group (definite separation not seen) and the extruded disc group of patients, the signal intensities of the herniated discs were compared with the signal intensities of the parent discs and were evaluated on T1-and T2-weighted images. We also assessed the presence of a notch within the herniated disc. In the sequestered disc group of patients (28 discs), only 5 discs (18%) showed obvious separation from the parent disc. Among the remaining 23 discs with indefinite separation, the notch was visible in 14 discs (61%) and 9 discs (39%) had no notch. In the extruded disc group (18 discs), the notch was visible in 2 (11%) discs and the difference between the two groups was statistically significant (ρ 0.0002). The signal intensities of the herniated discs on T1-weighted images were isointense in both the sequestered and extruded discs. The difference of incidence of high signal intensities on T2-weighted images was not statistically significant (ρ = 0.125). It is necessary to consider the possibility of the presence of a sequestered disc when a herniated disc material shows a notch

Ten-year in vivo wear measurement of a fully congruent mobile bearing unicompartmental knee arthroplasty.

Science.gov (United States)

Price, A J; Short, A; Kellett, C; Beard, D; Gill, H; Pandit, H; Dodd, C A F; Murray, D W

2005-11-01

Polyethylene particulate wear debris continues to be implicated in the aetiology of aseptic loosening following knee arthroplasty. The Oxford unicompartmental knee arthroplasty employs a spherical femoral component and a fully congruous meniscal bearing to increase contact area and theoretically reduce the potential for polyethylene wear. This study measures the in vivo ten-year linear wear of the device, using a roentgenstereophotogrammetric technique. In this in vivo study, seven medial Oxford unicompartmental prostheses, which had been implanted ten years previously were studied. Stereo pairs of radiographs were acquired for each patient and the films were analysed using a roentgen stereophotogrammetric analysis calibration and a computer-aided design model silhouette-fitting technique. Penetration of the femoral component into the original volume of the bearing was our estimate of linear wear. In addition, eight control patients were examined less than three weeks post-insertion of an Oxford prosthesis, where no wear would be expected. The control group showed no measured wear and suggested a system accuracy of 0.1 mm. At ten years, the mean linear wear rate was 0.02 mm/year. The results from this in vivo study confirm that the device has low ten-year linear wear in clinical practice. This may offer the device a survival advantage in the long term.

Instability of warped discs

Science.gov (United States)

Doǧan, S.; Nixon, C. J.; King, A. R.; Pringle, J. E.

2018-05-01

Accretion discs are generally warped. If a warp in a disc is too large, the disc can `break' apart into two or more distinct planes, with only tenuous connections between them. Further, if an initially planar disc is subject to a strong differential precession, then it can be torn apart into discrete annuli that precess effectively independently. In previous investigations, torque-balance formulae have been used to predict where and when the disc breaks into distinct parts. In this work, focusing on discs with Keplerian rotation and where the shearing motions driving the radial communication of the warp are damped locally by turbulence (the `diffusive' regime), we investigate the stability of warped discs to determine the precise criterion for an isolated warped disc to break. We find and solve the dispersion relation, which, in general, yields three roots. We provide a comprehensive analysis of this viscous-warp instability and the emergent growth rates and their dependence on disc parameters. The physics of the instability can be understood as a combination of (1) a term that would generally encapsulate the classical Lightman-Eardley instability in planar discs (given by ∂(νΣ)/∂Σ < 0) but is here modified by the warp to include ∂(ν1|ψ|)/∂|ψ| < 0, and (2) a similar condition acting on the diffusion of the warp amplitude given in simplified form by ∂(ν2|ψ|)/∂|ψ| < 0. We discuss our findings in the context of discs with an imposed precession, and comment on the implications for different astrophysical systems.

Metal-on-Metal Total Hip Resurfacing Arthroplasty

Science.gov (United States)

2006-01-01

alcohol and/or a nutritionally deficient diet may have a marked synergistic effect with the cardiotoxicity of cobalt. Conclusions MOM hip resurfacing arthroplasty has been shown to be an effective arthroplasty procedure as tested in younger patients. However, evidence for effectiveness is based only on 7 case series with short duration of follow-up (2.8–3.5 years). There are no RCTs or other well-controlled studies that compare MOM hip resurfacing with THR. Revision rates reported in the MOM studies using implants currently licensed in Canada (hybrid systems, uncemented acetabular, and cemented femoral) range from 0.3% to 3.6% for a mean follow-up ranging from 2.8 to 3.5 years. Fracture of femoral neck is not very common; it occurs in 0.4% to 2.2% of cases (as observed in a short follow-up period). All the studies that measured health outcomes have reported improvement in Harris Hip and SF-12 scores; 1 study reported significant reduction in pain and improvement in function, and 2 studies reported significant improvement in SF-12 scores. One study reported significant improvement in UCLA Hip scores. Concerns remain on the potential adverse effects of metal ions. Longer-term follow-up data will help to resolve the inconsistency of findings on adverse effects, including toxicity and carcinogenicity. Ontario-Based Economic Analysis The device cost for MOM ranges from $4,300 to $6,000 (Cdn). Traditional hip replacement devices cost about $2,000 (Cdn). Using Ontario Case Costing Initiative data, the total estimated costs for hip resurfacing surgery including physician fees, device fees, follow-up consultation, and postsurgery rehabilitation is about $15,000 (Cdn). Figure 1: Cost of Total Hip Replacement Surgery in Ontario Hip Resurfacing Surgery (Based on 2005/06 inflationary-adjusted rates) Weighted Average (Academic Community! al-inclusive hospitalization cost of surgery $ 6.767.18 Device Cost $ 5,400.00 Additional Medication $ 330.75 Follow-up Consultation $ 190.30 Rehab

Evolution of viscous discs. 3. Giant discs in symbiotic stars

Energy Technology Data Exchange (ETDEWEB)

Bath, G T [Oxford Univ. (UK). Dept. of Astrophysics; Pringle, J E [Cambridge Univ. (UK). Inst. of Astronomy

1982-10-01

The structure of time-dependent accretion discs in giant binaries with separation of the order of 10/sup 13/ cm is examined. Radiative ..cap alpha..-viscosity discs with ..cap alpha.. of order unity accreting on to main-sequence stars at accretion rates which generate luminosities greater than a giant companion decay on time-scales of the same order as the binary period, unlike those in dwarf nova binaries which decay on time-scales 100 times longer than the binary period. This results from the lower gravitational potential and consequent larger disc thickness (relative to the radius) of luminous 'giant' discs accreting at high accretion rates. The eruptions of the symbiotic binary C I Cygni are modelled by an ..cap alpha.. = 1 disc with outer radius 8.5 x 10/sup 12/ cm and a sequence of five mass-transfer bursts at rates between 1.5 x 10/sup 21/ and 4 x 10/sup 22/g s/sup -1/.

Shoulder arthroplasty for sequelae of poliomyelitis.

Science.gov (United States)

Werthel, Jean-David; Schoch, Bradley; Sperling, John W; Cofield, Robert; Elhassan, Bassem T

2016-05-01

Polio infection can often lead to orthopedic complications such as arthritis, osteoporosis, muscle weakness, skeletal deformation, and chronic instability of the joints. The purpose of this study was to assess the outcomes and associated complications of arthroplasty in shoulders with sequelae of poliomyelitis. Seven patients (average age, 70 years) were treated between 1976 and 2013 with shoulder arthroplasty for the sequelae of polio. One patient underwent reverse shoulder arthroplasty, 2 had a hemiarthroplasty, and 4 had total shoulder arthroplasty. Average follow-up was 87 months. Outcome measures included pain, range of motion, and postoperative modified Neer ratings. Overall pain scores improved from 5 to 1.6 points (on a 5-point scale) after shoulder arthroplasty. Six shoulders had no or mild pain at latest follow-up, and 6 shoulders rated the result as much better or better. Mean shoulder elevation improved from 72° to 129°, and external rotation improved from 11° to 56°. Average strength in elevation decreased from 3.9 to 3.4 postoperatively, and external rotation strength decreased from 3.9 to 3.3. This, however, did not reach significance. Evidence of muscle imbalance with radiographic instability was found in 4 shoulders that demonstrated superior subluxation, anterior subluxation, or both. This remained asymptomatic. No shoulder required revision or reoperation. Shoulder arthroplasty provides significant pain relief and improved motion in patients with sequelae of poliomyelitis. Muscle weakness may be responsible for postoperative instability, and careful selection of the patient with good upper extremity muscles must be made. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Superluminous accretion discs

Energy Technology Data Exchange (ETDEWEB)

Sikora, M [Cambridge Univ. (UK). Inst. of Astronomy; Polska Akademia Nauk, Warsaw. Centrum Astronomiczne)

1981-07-01

Upper limits are computed for the total luminosities and collimation of radiation from thick, radiation supported accretion discs around black holes. Numerical results are obtained for the 'extreme' discs with rsub(out) = 10/sup 3/ GMsub(BH)/c/sup 2/, the angular momentum of the black hole being Jsub(BH) = 0.998 GMsub(BH)/c. The high luminosity (L approximately 8.5 Lsub(Edd)) and substantial collimation of radiation found for these discs indicate that such discs can explain both the high luminosities of quasars and similar objects and may produce some of the observed beams and jets.

Instability after total hip arthroplasty

Science.gov (United States)

Werner, Brian C; Brown, Thomas E

2012-01-01

Instability following total hip arthroplasty (THA) is an unfortunately frequent and serious problem that requires thorough evaluation and preoperative planning before surgical intervention. Prevention through optimal index surgery is of great importance, as the management of an unstable THA is challenging even for an experienced joints surgeon. However, even after well-planned surgery, a significant incidence of recurrent instability still exists. Non-operative management is often successful if the components are well-fixed and correctly positioned in the absence of neurocognitive disorders. If conservative management fails, surgical options include revision of malpositioned components; exchange of modular components such as the femoral head and acetabular liner; bipolar arthroplasty; tripolar arthroplasty; use of a larger femoral head; use of a constrained liner; soft tissue reinforcement and advancement of the greater trochanter. PMID:22919568

The Efficacy and Safety of Autologous Transfusion in Unilateral Total Knee Arthroplasty

OpenAIRE

Yoo, Moon-Jib; Park, Hee-Gon; Ryu, Jee-Won; Kim, Jeong-Sang

2015-01-01

Purpose Although allogeneic blood transfusion is the most common method of transfusion in total knee arthroplasty (TKA), there are reports showing significant decrease in the amount of allogeneic transfusion and incidence of side effects after combined use of autologous transfusion. The purpose of this study is to investigate the efficacy of using an autologous transfusion device in TKA. Materials and Methods Patients who underwent TKA at our institution from January 2003 to January 2014 were...

Tracing Planets in Circumstellar Discs

Directory of Open Access Journals (Sweden)

Uribe Ana L.

2013-04-01

Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

Preoperative Optimization of Total Joint Arthroplasty Surgical Risk: Obesity.

Science.gov (United States)

Fournier, Matthew N; Hallock, Justin; Mihalko, William M

2016-08-01

Obesity is a problem that is increasing in prevalence in the United States and in other countries, and it is a common comorbidity in patients seeking total joint arthroplasty for degenerative musculoskeletal diseases. Obesity, as well as commonly associated comorbidities such as diabetes mellitus, cardiovascular disease, and those contributing to the diagnosis of metabolic syndrome, have been shown to have detrimental effects on total joint arthroplasty outcomes. Although there are effective surgical and nonsurgical interventions which can result in weight loss in these patients, concomitant benefit on arthroplasty outcomes is not clear. Preoperative optimization of surgical risk in obese total joint arthroplasty patients is an important point of intervention to improve arthroplasty outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

TOTAL HIP ARTHROPLASTY IN CHILDREN WHO HAVE UNDERGONE ARTHROPLASTY WITH DEMINERALIZED BONE-CARTILAGE ALLOCUPS

Directory of Open Access Journals (Sweden)

Vladimir E. Baskov

2017-03-01

Full Text Available Introduction. Treating children with degenerative dystrophic diseases of the hip joint has become one of the most acute problems in contemporary orthopedics. Until recently, we performed arthroplasty by demineralized bone-cartilage allocups (DBCA in the Clinic of the Hip Joint Pathology of the Turner Scientific and Research Institute for Children’s Orthopedics for patients showing clinical and radiological signs of irreversible destruction of the hip joint; we carried out this procedure to preserve the function of the lower limb. However, over the last 8 years, we have changed our protocol for children older than 12 years of age and have replaced DBCA with total hip replacement. In a number of cases, total hip replacement was performed after a previous intervention involving arthroplasty with DBCA. Objective. To determine the technical peculiarities of total hip replacement after a previous intervention involving arthroplasty with DBCA. Material and methods. We analyzed the results of treatment involving various types of hip pathology in 13 children (100% aged between 15 and 16 years [8 girls (61.5% and 5 boys (38.5%]. The medical histories of all 13 children (100% showed repeated operations on the hip joint, ultimately resulting in arthroplasty with DBCA. All 13 children (100% underwent a total hip replacement. Upon hip replacement, all 13 patients (100% showed a pronounced thinning and hardening of the edges and the bottom of the acetabulum, which created some difficulties in the process of acetabular component implantation. The transformation of DBCA was not evident in any of the 13 cases (100%. Results. During the observation period of 3–5 years following total hip arthroplasty, all 13 cases (100% showed recovery in the range of motion and absence of pain. An important criterion for evaluating the quality of care was the complete social and domestic adaptation of all 13 children (100% during the period from 6 to 9 months following total

Total hip arthroplasty in children who have undergone arthroplasty with demineralized bone-cartilage allocups

Directory of Open Access Journals (Sweden)

Vladimir E. Baskov

2017-03-01

Full Text Available Introduction. Treating children with degenerative dystrophic diseases of the hip joint has become one of the most acute problems in contemporary orthopedics. Until recently, we performed arthroplasty by demineralized bone-cartilage allocups (DBCA in the Clinic of the Hip Joint Pathology of the Turner Scientific and Research Institute for Children’s Orthopedics for patients showing clinical and radiological signs of irreversible destruction of the hip joint; we carried out this procedure to preserve the function of the lower limb. However, over the last 8 years, we have changed our protocol for children older than 12 years of age and have replaced DBCA with total hip replacement. In a number of cases, total hip replacement was performed after a previous intervention involving arthroplasty with DBCA. Objective. To determine the technical peculiarities of total hip replacement after a previous intervention involving arthroplasty with DBCA. Material and methods. We analyzed the results of treatment involving various types of hip pathology in 13 children (100% aged between 15 and 16 years [8 girls (61.5% and 5 boys (38.5%]. The medical histories of all 13 children (100% showed repeated operations on the hip joint, ultimately resulting in arthroplasty with DBCA. All 13 children (100% underwent a total hip replacement. Upon hip replacement, all 13 patients (100% showed a pronounced thinning and hardening of the edges and the bottom of the acetabulum, which created some difficulties in the process of acetabular component implantation. The transformation of DBCA was not evident in any of the 13 cases (100%. Results. During the observation period of 3–5 years following total hip arthroplasty, all 13 cases (100% showed recovery in the range of motion and absence of pain. An important criterion for evaluating the quality of care was the complete social and domestic adaptation of all 13 children (100% during the period from 6 to 9 months following total

Risk factors for blood transfusion after shoulder arthroplasty.

Science.gov (United States)

Padegimas, E M; Clyde, C T; Zmistowski, B M; Restrepo, C; Williams, G R; Namdari, S

2016-02-01

Currently, there is little information about the need for peri-operative blood transfusion in patients undergoing shoulder arthroplasty. The purpose of this study was to identify the rate of transfusion and its predisposing factors, and to establish a blood conservation strategy. We identified all patients who had undergone shoulder arthroplasty at our hospital between 1 January 2011 and 31 December 2013. The rate of transfusion was determined from the patient's records. While there were exceptions, patients typically underwent transfusion if they had a level of haemoglobin of transfusion. High- and low-risk cohorts for transfusion were identified from a receiver operating characteristic (ROC) curve. Of 1174 shoulder arthroplasties performed on 1081 patients, 53 cases (4.5%) required transfusion post-operatively. Predictors of blood transfusion were a lower pre-operative haematocrit (p transfusion. In total 48 of the 436 (11%) shoulder arthroplasties with a pre-operative haematocrit transfusion compared with five of the 738 (0.70%) shoulder arthroplasties with a haematocrit above this level. We found that transfusion was needed less frequently than previously described for shoulder arthroplasty. Patients with a pre-operative haematocrit blood transfusion, while those with a haematocrit above this level are unlikely to require transfusion. The rate of transfusion after shoulder arthroplasty is under 5%, and those with a pre-operative haematocrit greater than or equal to 39.6% have a very low likelihood (transfusion. ©2016 The British Editorial Society of Bone & Joint Surgery.

Digital versus analogue preoperative planning of total hip arthroplasties - A randomized clinical trial of 210 total hip arthroplasties

NARCIS (Netherlands)

The, Bertram; Verdonschot, Nico; van Horn, Jim R.; van Ooijen, Peter M. A.; Diercks, Ron L.

The objective of this randomized clinical trial was to compare the clinical and technical results of digital preoperative planning for primary total hip arthroplasties with analogue planning. Two hundred and ten total hip arthroplasties were randomized. All plans were constructed on standardized

Semiconductor-based, large-area, flexible, electronic devices

Science.gov (United States)

Goyal, Amit [Knoxville, TN

2011-03-15

Novel articles and methods to fabricate the same resulting in flexible, large-area, triaxially textured, single-crystal or single-crystal-like, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

A reactor/separator device for use in automated solid phase immunoassay

International Nuclear Information System (INIS)

Farina, P.R.; Ordonez, K.P.; Siewers, I.J.

1979-01-01

A reactor/separator device is described for use in automated solid phase immunoassay, including radioimmunoassays. The device is a column fitted at the bottom portion with a water impermeable disc which can hold, for example, immunoabsorbents, immobilized antisera or ion exchange resins. When the contents of the column supported by the disc are brought into contact with an aqueous phase containing reagents or reactants, a chemical reaction is initiated. After the reaction, centrifugally applied pressure forces the aqueous phase through the filter disc making it water permeable and separating a desired component for subsequent analysis. The reactor/separator device of the present invention permits kinetic solid phase assays (non-equilibrium conditions) to be carried out which would be difficult to perform by other conventional methods. (author)

the choice of arthroplasty implants in a developing country

African Journals Online (AJOL)

The use of arthroplasty in end stage arthritis in Kenya is now established. Arthroplasty is now carried out in a number of the main city hospitals, particularly in the private sector and in some mission hospitals. Some patients travel out of the country, particularly to India in search of arthroplasty. There is, also, an increasing.

Accretion discs around neutron stars

International Nuclear Information System (INIS)

Pringle, J.E.

1982-01-01

If the central object in the disc is a neutron star, then we do not need the disc itself to produce the X-rays. In other words, the disc structure itself is not important as long as it plays the role of depositing matter on the neutron star at a sufficient rate to produce the X-ray flux. Similarly, in the outer disc regions, the main disc luminosity comes from absorption and reradiation of X-ray photons and not from the intrinsic, viscously-produced, local energy production rate. These two points indicate why in the compact binary X-ray sources confrontation between disc theory and observations is not generally practicable. For this reason I will divide my talk into two parts: one on observational discs in which I discuss what observational evidence there is for discs in the compact X-ray sources and what the evidence can tell the theorist about disc behaviour, and the other on theoretical discs where I consider in what ways theoretical arguments can put limits or cast doubt on some of the empirical models put forward to explain the observations. (orig.)

Expectations in patients with total knee arthroplasty.

Science.gov (United States)

Tekin, Burcu; Unver, Bayram; Karatosun, Vasfi

2012-01-01

The primary objective of total knee arthroplasty (TKA) is to decrease pain and restore functional knee joint. Current hypotheses indicate higher knee flexion is required in terms of life style, culture and expectations in Eastern communities. Therefore, society-specific features related to life style and cultural habits are needed. The objective of this study was to investigate the expectations of patients undergoing TKA. The study included 131 patients (18 male, 113 female; mean age: 66.2 ± 8.3 years) who underwent cemented TKA due to knee osteoarthritis. All patients were operated by the same surgeon using the same implant and surgical technique. Patients were evaluated using the Hospital for Special Surgery (HSS) knee score, a 15-item clinical knee assessment questionnaire and the HSS knee arthroplasty expectation questionnaire. Mean HSS score for the right knee was 89.2 ± 10.5 and for the left knee was 89.6 ± 9.4. The two most expected outcomes were improvements in pain (99.2%) and gait (96.2%) and the two least expected outcomes were improvements in psychological well-being (22.9%) and communicative skills (35.1%). Expectations were not affected by education and working conditions. Patients' most expected outcomes were improvement in pain and restoration of function (gait, climbing stairs and no need of assistive devices), similar to Western and American communities.

CT and MRI of hip arthroplasty

International Nuclear Information System (INIS)

Cahir, J.G.; Toms, A.P.; Marshall, T.J.; Wimhurst, J.; Nolan, J.

2007-01-01

Plain films are the initial imaging method of choice for evaluation of hip arthroplasty. Recent advances in technology and imaging techniques have largely overcome the problems of beam hardening in computed tomography (CT) and magnetic susceptibility artefact in magnetic resonance imaging (MRI). CT and MRI have now become useful imaging techniques in the assessment of hip arthroplasty

The innovation trap: modular neck in total hip arthroplasty

Directory of Open Access Journals (Sweden)

Samo Karel Fokter

2017-04-01

Full Text Available Background: Innovations play the key role in the success of orthopaedic surgery. However, even minor modifications in the established concepts and proven designs may result in disasters. The endemic of modular femoral neck fracture (24 cases of about 4000 implanted in fully modular total hip arthroplasty, popular in our country for the last 20 years, seems to challenge us with such an unfortunate consequences. The aim of this report was to analyze the extent and the causes of the problem on the one hand and to propose possible solutions on the other.Methods: Literature search for problems associated with Profemur Z (or earlier versions with the same taper-cone design fully-modular femoral stem made of titanium alloy (Ti6Al4V was performed, and hip arthroplasty registries were searched to evaluate the failure rates of the mentioned design. Mechanisms of failure were studied to get in-depth understanding of this particular hip reconstruction device.Results: Since 2010 onwards, several case reports on catastrophic modular femoral neck fractures of Profemur Z were published. Te frst Slovenian case was described in 2012. The first two larger series with modular femoral neck fractures were published in 2016. Te Australian Joint Replacement Registry was the first to discover increased revision rates due to fractures of this hip reconstruction system. Public Agency of the Republic of Slovenia for Medicinal Products and Medical Devices (JAZMP received frst two reports regarding Profemur Z modular neck complication from abroad in 2010, the first Slovenian report was received in 2012, and altogether 7 reports from Slovenian hospitals were received until December 2016. Corrosion at the neck-taper interface, where two equal or different materials are subject to constant wear in the presence of body fluids, is assumed to be responsible for the unacceptable high failure rate.Conclusions: Manufacturers are responsible to produce and market only safe devices

Simultaneous and staged bilateral total hip arthroplasty

DEFF Research Database (Denmark)

Lindberg-Larsen, Martin; Joergensen, Christoffer Calov; Husted, Henrik

2013-01-01

Bilateral total hip arthroplasty (BTHA) and bilateral simultaneous total hip arthroplasty (BSTHA) are done increasingly. Previous studies evaluating outcomes after bilateral procedures have found different results. The aim of this study was to investigate length of hospital stay (LOS), 30 days...

Double rupture disc experience

International Nuclear Information System (INIS)

1979-01-01

Result of these observations, comparisons and evaluations can be summarized in the following list of concerns regarding the use of double rupture discs coupled to the liquid space of a steam generator that is subjected to a large leak sodium water reaction event. Single rupture disc show delayed collapse characteristics in LLTR Series I and double disc assemblies are presumed to be more complex with additional delay before opening to give pressure relief. Delayed failure increases pressures in the IHTS and must be adequately covered by design requirements. With CRBR design, the first disc may fail only partially reducing the loading on the second disc with the result that relief performance may not meet requirements

Imaging patellar complications after knee arthroplasty

International Nuclear Information System (INIS)

Melloni, Pietro; Valls, Rafael; Veintemillas, Maite

2008-01-01

The purpose of this study is to describe complications affecting the patella in patients with total or partial knee arthroplasty. We respectively analysed plain-film radiographs, as well as ultrasound images when acquired, in a consecutive series of 1272 patients. The mean interval from knee replacement to patellar complications was 5 years and 7 months (range, 5 months to 14 years). The complications described include fracture, instability, dislocation or luxation, necrosis of the patella, infection of the patella, erosion of the patella, patellar impingement on the prosthesis and patellar or quadricipital tendon tear. We discuss the pathological imaging findings in the patella and their differential diagnosis after knee arthroplasty. Patellar complications after knee arthroplasty are uncommon but often potentially serious

Imaging patellar complications after knee arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Melloni, Pietro [Unitat de Imatge d' Alta Tecnologia, Centre Diagnostic, Corporacio Parc Tauli, Universitat Autonoma de Barcelona, Sabadell (Barcelona) (Spain)], E-mail: pmelloni@cspt.es; Valls, Rafael; Veintemillas, Maite [Unitat de Imatge d' Alta Tecnologia, Centre Diagnostic, Corporacio Parc Tauli, Universitat Autonoma de Barcelona, Sabadell (Barcelona) (Spain)

2008-03-15

The purpose of this study is to describe complications affecting the patella in patients with total or partial knee arthroplasty. We respectively analysed plain-film radiographs, as well as ultrasound images when acquired, in a consecutive series of 1272 patients. The mean interval from knee replacement to patellar complications was 5 years and 7 months (range, 5 months to 14 years). The complications described include fracture, instability, dislocation or luxation, necrosis of the patella, infection of the patella, erosion of the patella, patellar impingement on the prosthesis and patellar or quadricipital tendon tear. We discuss the pathological imaging findings in the patella and their differential diagnosis after knee arthroplasty. Patellar complications after knee arthroplasty are uncommon but often potentially serious.

Radially truncated galactic discs

NARCIS (Netherlands)

Grijs, R. de; Kregel, M.; Wesson, K H

2000-01-01

Abstract: We present the first results of a systematic analysis of radially truncatedexponential discs for four galaxies of a sample of disc-dominated edge-onspiral galaxies. Edge-on galaxies are very useful for the study of truncatedgalactic discs, since we can follow their light distributions out

Research Regarding the Manufacturing through AM Technologies of an Implant for Cervical Disc Replacement

Directory of Open Access Journals (Sweden)

Miron-Borzan Cristina Stefana

2017-01-01

Full Text Available Worldwide, accidents are one of the main causes of illness in developed and undeveloped socio-economic countries. Additive Manufacturing (AM technologies bring extremely useful and advantageous applications for the new neurosurgical procedures. Because the surgical insertion of devices for cervical disc replacement is very difficult, the development of new devices that can minimize these disadvantages, are needed. The aim of this paper was to improve the characteristics of an implant for cervical intervertebral disc replacement, a model based on an existing implant. A cervical cage designed for stabilization and arthrodesis between the cervical vertebrae was analyzed. A new design of a cage that have some improvements, useful for patient safety, as well as for facilitating the surgery was developed. The new proposed design was verified through Fine Element Analysis.

Investigation of biomechanical behavior of lumbar vertebral segments with dynamic stabilization device using finite element approach

Science.gov (United States)

Deoghare, Ashish B.; Kashyap, Siddharth; Padole, Pramod M.

2013-03-01

Degenerative disc disease is a major source of lower back pain and significantly alters the biomechanics of the lumbar spine. Dynamic stabilization device is a remedial technique which uses flexible materials to stabilize the affected lumbar region while preserving the natural anatomy of the spine. The main objective of this research work is to investigate the stiffness variation of dynamic stabilization device under various loading conditions under compression, axial rotation and flexion. Three dimensional model of the two segment lumbar spine is developed using computed tomography (CT) scan images. The lumbar structure developed is analyzed in ANSYS workbench. Two types of dynamic stabilization are considered: one with stabilizing device as pedicle instrumentation and second with stabilization device inserted around the inter-vertebral disc. Analysis suggests that proper positioning of the dynamic stabilization device is of paramount significance prior to the surgery. Inserting the device in the posterior region indicates the adverse effects as it shows increase in the deformation of the inter-vertebral disc. Analysis executed by positioning stabilizing device around the inter-vertebral disc yields better result for various stiffness values under compression and other loadings. [Figure not available: see fulltext.

Double-disc gate valve

International Nuclear Information System (INIS)

Wheatley, S.J.

1979-01-01

The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

Evaluation of gait performance of knee osteoarthritis patients after total knee arthroplasty with different assistive devices

Directory of Open Access Journals (Sweden)

Ana Tereso

Full Text Available IntroductionNowadays Knee Osteoarthritis (KOA affects a large percentage of the elderly, and one solution is to perform a Total Knee Arthroplasty (TKA. In this paper, one intends to study the gait and posture of these patients after the TKA, while walking with three assistive devices (ADs (crutches, standard walker (SW and rollator with forearm supports (RFS.MethodsEleven patients were evaluated in 2 phases: 5 days and 15 days after surgery. This evaluation was conducted with two inertial sensors, one attached to the operated leg ankle, to measure spatiotemporal parameters, and the other at the sacrum, to measure posture and fall risk-related parameters. Multivariate analysis of variance (MANOVA with repeated measures was performed to detect group differences.ResultsThe MANOVA results show that all spatiotemporal parameters are significantly different (p0.05. The interaction between time and ADs only affects significantly the velocity (p<0.05. In terms of fall risk parameters, time only significantly affects the antero-posterior direction (p<0.05 and ADs affects significantly root mean square in medio-lateral direction (p<0.05. In terms of interaction between time and ADs, there are no statistical significant differences.ConclusionThis study concludes that depending on the state of recovery of the patient, different ADs should be prescribed. On the overall, standard walker is good to give stability to the patient and RFS allows the patient to present a gait pattern closer to a natural gait.

Optic disc oedema

DEFF Research Database (Denmark)

Nielsen, Marianne Kromann; Hamann, Steffen

2014-01-01

Optic disc oedema describes the nonspecific, localized swelling of the optic nerve head regardless of aetiology. Therefore, differentiating among the various aetiologies depends on a thorough history and knowledge of the clinical characteristics of the underlying conditions. Papilloedema strictly...... refers to optic disc oedema as a consequence of elevated intracranial pressure. It is usually a bilateral condition and visual function is preserved until late. Optic disc oedema caused by an anterior optic neuropathy is usually unilateral and accompanied by the loss of visual function....

CURBSIDE CONSULTATION IN KNEE ARTHROPLASTY: 49 CLINICAL QUESTIONS

Directory of Open Access Journals (Sweden)

Craig J. Della Vale

2008-12-01

Full Text Available A user- friendly reference for decision making in complicated cases of knee arthroplasty desingned in a question and answers format composed of articles containing current concepts and preferences of experts in total knee replacement surgery, enhanced by several images, diagrams and references and written in the form of a casual advice by Craig J. Della Vale, MD. and his collaborators. PURPOSE By this practical reference of knee arthroplasty, the editor and the contributors have aimed providing straightforward and brief answers, evidence-based advices, their preference and opinions containing current concepts for unanswered questions about complicated cases in total knee replacement surgery which are often controversial and not addressed clearly in traditional knee arthroplasty references. FEATURES There are 49 subjects each written by a different expert designed in 4 sections in a question and answers format including several images and diagrams and also essential references at the end of each article. In the first section preoperative questions is subjected including indications, unicompartmental osteoarthritis of the knee, patient with vascular problems, donating blood, bilateral arthroplasty, patellar resurfacing, range of motion, bearing surface, contraindications, teaching class for patients prior surgery. The second section is about intraoperative questions including skin incision, patella femoral maltracking, femoral component rotation, tibial component rotation, lateral release, femoral component sizing, flexion instability, varus deformity, and valgus deformity, tightness in extension, iatrogenic MCL injury, antibiotic-loaded cement, and perioperative pain. The third section subjects postoperative questions including wound drainage, preventing tromboembolic events, vascular complications, foot drop, manipulation under anesthesia, patella fractures, supracondylar femur fractures, acute extensor mechanism disruptions. In the fourth

Advances in Proximal Interphalangeal Joint Arthroplasty: Biomechanics and Biomaterials.

Science.gov (United States)

Zhu, Andy F; Rahgozar, Paymon; Chung, Kevin C

2018-05-01

Proximal interphalangeal (PIP) joint arthritis is a debilitating condition. The complexity of the joint makes management particularly challenging. Treatment of PIP arthritis requires an understanding of the biomechanics of the joint. PIP joint arthroplasty is one treatment option that has evolved over time. Advances in biomaterials have improved and expanded arthroplasty design. This article reviews biomechanics and arthroplasty design of the PIP joint. Copyright © 2018 Elsevier Inc. All rights reserved.

Physical activity of elderly patients after total hip arthroplasty.

Science.gov (United States)

Cukras, Zbigniew; Praczko, Katarzyna; Kostka, Tomasz; Jegier, Anna

2007-01-01

Total hip arthroplasty (THA) is the most common method of treatment of severe hip osteoarthritis. There is little data concerning the physical activity of total hip arthroplasty patients in Poland and investigations to explore this area are useful. The aim of the study was to describe the post-operative physical activity of total hip arthroplasty patients. A total of 146 adult people were examined, among which 28 men and 41 women had undergone total hip arthroplasty due to primary osteoarthritis of the hip, while another 32 men and 41 women matched for age who had not undergone hip surgery for osteoarthritis served as controls. The physical activity of study participants was assessed with the 7-Day Physical Activity Recall Questionnaire. All participants were also asked about the type and amount of physical activity they engaged in to maintain good health. Physical activity measured as the total amount of calories expended through physical activity per week was similar in the post-THA patients compared to the controls. The only differences were a smaller amount of calories expended during low-intensity physical activity by men after total hip arthroplasty compared to men who had not undergone surgery for osteoarthritis and a smaller amount of calories expended through high-intensity physical activity by women after total hip arthroplasty compared to female controls. The kinds of recreational physical activity most commonly practised by patients a mean of two years after total hip arthroplasty were marching, bicycling and general body conditioning exercises (usually the continuation of exercises recommended during post-operative rehabilitation). The percentage of post-THA patients undertaking physical activity for the prevention of non-communicable diseases was low. Physical activity should be more effectively encouraged in patients after total hip arthroplasty.

Eradication of multidrug-resistant Acinetobacter baumannii in a female patient with total hip arthroplasty, with debridement and retention: a case report

Directory of Open Access Journals (Sweden)

Beieler Alison M

2009-02-01

Full Text Available Abstract Introduction Multidrug-resistant Acinetobacter baumannii has become a significant cause of healthcare-associated infections, but few reports have addressed Acinetobacter baumannii infections associated with orthopedic devices. The current recommended treatment for complicated infections due to orthopedic devices, including resistant gram-negative rods, consists of antimicrobial therapy with debridement and removal of implants. Case presentation The patient, a 47-year-old woman, had previously had a prior total hip arthroplasty at 16 years of age for a complex femoral neck fracture, and multiple subsequent revisions. This time, she underwent a fifth revision secondary to pain. Surgery was complicated by hypotension resulting in transfer to the intensive care unit and prolonged respiratory failure. She received peri-operative cefazolin but postoperatively developed surgical wound drainage requiring debridement of a hematoma. Cultures of this grew ampicillin-sensitive Enterococcus and Acinetobacter baumannii (sensitive only to amikacin and imipenem. The patient was started on imipenem. Removal of the total hip arthroplasty was not recommended because of the recent surgical complications, and the patient was eventually discharged home. She was seen weekly for laboratory tests and examinations and, after 4 months of therapy, the imipenem was discontinued. She did well clinically for 7 months before recurrent pain led to removal of the total hip arthroplasty. Intra-operative cultures grew ampicillin-sensitive Enterococcus and coagulase-negative Staphylococcus but no multidrug-resistant Acinetobacter baumannii. The patient received ampicillin for 8 weeks and had not had recurrent infection at the time of writing, 37 months after discontinuing imipenem. Conclusion We describe the successful treatment of an acute infection from multidrug-resistant Acinetobacter baumannii with debridement and retention of the total hip arthroplasty, using

Total knee arthroplasty in patients with a previous patellectomy.

Science.gov (United States)

Maslow, Jed; Zuckerman, Joseph D; Immerman, Igor

2013-01-01

Post-patellectomy patients represent a specific subgroup of patients that may develop arthritis and persistent knee pain and potentially require treatment with total knee arthroplasty. This article reviews the treatment and functional outcomes following total knee arthroplasty in patients with prior patellectomy. A case report is presented as an example of the clinical management of a post-patellectomy patient with significant knee pain and disability treated with total knee arthroplasty. Emphasis will be placed in decision- making, specifically with the use of a posterior stabilized implant. In addition, postoperative strengthening of the quadriceps is essential to compensate for the lack of the patella and increase the success of total knee arthroplasty in this subgroup of patients.

Can an arthroplasty risk score predict bundled care events after total joint arthroplasty?

Directory of Open Access Journals (Sweden)

Blair S. Ashley, MD

2018-03-01

Full Text Available Background: The validated Arthroplasty Risk Score (ARS predicts the need for postoperative triage to an intensive care setting. We hypothesized that the ARS may also predict hospital length of stay (LOS, discharge disposition, and episode-of-care cost (EOCC. Methods: We retrospectively reviewed a series of 704 patients undergoing primary total hip and knee arthroplasty over 17 months. Patient characteristics, 90-day EOCC, LOS, and readmission rates were compared before and after ARS implementation. Results: ARS implementation was associated with fewer patients going to a skilled nursing or rehabilitation facility after discharge (63% vs 74%, P = .002. There was no difference in LOS, EOCC, readmission rates, or complications. While the adoption of the ARS did not change the mean EOCC, ARS >3 was predictive of high EOCC outlier (odds ratio 2.65, 95% confidence interval 1.40-5.01, P = .003. Increased ARS correlated with increased EOCC (P = .003. Conclusions: Implementation of the ARS was associated with increased disposition to home. It was predictive of high EOCC and should be considered in risk adjustment variables in alternative payment models. Keywords: Bundled payments, Risk stratification, Arthroplasty

Proto-planetary disc evolution and dispersal

Science.gov (United States)

Rosotti, Giovanni Pietro

2015-05-01

Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion

CT discography for cervical soft disc hernia

Energy Technology Data Exchange (ETDEWEB)

Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

1985-03-01

In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five intervertebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernias between the median and posterolateral discs. They were also valuable in classifying types of hernias and surgical approaches.

Fast-track revision knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B

2011-01-01

Abstract Background and purpose Fast-track surgery has reduced the length of hospital stay (LOS), morbidity, and convalescence in primary hip and knee arthroplasty (TKA). We assessed whether patients undergoing revision TKA for non-septic indications might also benefit from fast-track surgery....... Methods 29 patients were operated with 30 revision arthroplasties. Median age was 67 (34-84) years. All patients followed a standardized fast-track set-up designed for primary TKA. We determined the outcome regarding LOS, morbidity, mortality, and satisfaction. Results Median LOS was 2 (1-4) days...

Fast-track hip and knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik

2012-01-01

Fast-track hip and knee arthroplasty aims at giving the patients the best available treatment at all times, being a dynamic entity. Fast-track combines evidence-based, clinical features with organizational optimization including a revision of traditions resulting in a streamlined pathway from...... on clinical and organizational aspects of fast-track hip and knee arthroplasty (I–IX). A detailed description of the fast-track set-up and its components is provided. Major results include identification of patient characteristics to predict length of stay and satisfaction with different aspects...... of the hospital stay (I); how to optimize analgesia by using a compression bandage in total knee arthroplasty (II); the clinical and organizational set-up facilitating or acting as barriers for early discharge (III); safety aspects following fast-track in the form of few readmissions in general (IV) and few...

CT discography for cervical soft disc hernia

International Nuclear Information System (INIS)

Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

1985-01-01

In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five interververtebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernians between the median and posterolateral discs. They were also valuable in classifying types of hernians and surgical aproaches. (author)

Patient-reported outcome after fast-track knee arthroplasty

DEFF Research Database (Denmark)

Larsen, Kristian; Hansen, Torben B; Søballe, Kjeld

2012-01-01

PURPOSE: The purpose of this study was to describe patient-related functional outcomes after fast-track total knee arthroplasty and unicompartmental knee arthroplasty. Furthermore, we wanted to assess physical areas where an additional need for rehabilitation could be identified, and finally, we...

Design and fabrication of substrates with microstructures for bio-applications through the modified optical disc process

Science.gov (United States)

Chiu, Kuo-Chi; Chang, Sheng-Li; Huang, Chu-Yu; Guan, Hann-Wen

2011-05-01

The modified optical disc process has been investigated and demonstrated to enable fast prototyping in fabricating molds and replicating substrates with various microstructures including micro-chambers and micro-channels. A disc-like microfluidic device was created and the testing results showed good performance in bonding and packaging. The switching of the nozzle-like micro-valve was also validated to work well. Furthermore, the relevant procedures of liquid samples loading, separating and mixing were also accomplished through food experiments.

Well device for removing small objects

Energy Technology Data Exchange (ETDEWEB)

Rastorguyev, M.A.; Mubashirov, S.G.; Nikolayev, G.I.; Prokopov, O.I.

1982-01-01

A well device is proposed for removing small objects. It contains a hollow housing with worm and crown installed with the possibility of rotation in relation to the housing. It is distinguished by the fact that in order to increase reliability of holding the trapped objects, on the lower end of the housing there is a disc which forms with the housing a chamber for the trapped objects. In this case the disc is made with sector slit, one of whose sidewalls is superposed with the worm blade rigidly connected to the disc, while along the other side wall a plate is vertically attached.

[Sport activity after hip and knee arthroplasty].

Science.gov (United States)

Keren, Amit; Berkovich, Yaron; Berkovitch, Yaron; Soudry, Michael

2013-11-01

Joint arthroplasty is one of the commonest surgical procedures in orthopedic surgery. In recent years there was an increase in the number of procedures, patient satisfaction and implant survival. Originally, these operations were designed for old patients in order to relieve pain and to enable ambulation. Over the past few years, these operations have become common in younger patients which desire to return to activity, including sports activities. The importance of physical activity is a well known fact. In recent years it became clear that with the proper physical activity the outcomes of the operations are better. There are several types of arthroplasty. Many factors influence the outcome of the operation apart from the post-surgery physical activity. These factors include patient factors, surgical technique and type of arthroplasty. This review summarizes the recommendations for sports activities after hip and knee arthroplasties. These activities are evaluated according to surgeons' recommendations, stress applied on the implant and long term outcomes. The recommended sports activities after joint arthroplasties are walking, swimming and cycling. Soccer, basketball and jogging are not advised. Tennis, downhill skiing and horse riding are recommended with previous experience. There are many more sports activities that patients can participate in, and it is important that the patient discuss the different options prior to the operation. Since these operations are so common, many non-orthopedic physicians encounter these patients in their practice. They should be acquainted with the recommendations for sports activities and encourage them.

Gravitating discs around black holes

International Nuclear Information System (INIS)

Karas, V; Hure, J-M; Semerak, O

2004-01-01

Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole-disc system using analytical solutions of stationary, axially symmetric Einstein equations. Then, more detailed considerations are focused to the middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring. However, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging are completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the surrounding environment. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star-disc interactions, which can be recognized in observational properties, such as the relation between the central mass and stellar velocity dispersion. (topical review)

Imaging of hip joint arthroplasty

International Nuclear Information System (INIS)

Mayerhoefer, M.E.; Fruehwald-Pallamar, J.; Czerny, C.

2009-01-01

The hip joint is the largest joint in the human body and consequently, its evaluation by diagnostic imaging is highly important. This includes imaging of hip joint arthroplasty, which is used to avoid joint immobility following a wide spectrum of diseases, such as end-stage degenerative disease, avascular necrosis of the femoral head or post-traumatic fractures. Conventional radiography is still the standard imaging modality for the evaluation of hip arthroplasty both directly following surgery and for periodical follow-up. In the majority of cases conventional radiography enables adequate assessment of early and late complications that can arise following hip arthroplasty, such as loosening, prosthetic or periprosthetic fracture, luxation, infection and soft tissue calcification. If the diagnosis cannot be established by means of radiography, advanced imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI), with or without injection of contrast media, may provide additional information. This is particularly true for the depiction of inflammatory processes. Regardless of the imaging modality used patients' clinical symptoms must also be taken into account in order to establish the correct diagnosis. (orig.) [de

Postoperative effects of neuromuscular exercise prior to hip or knee arthroplasty

DEFF Research Database (Denmark)

Villadsen, Allan; Overgaard, Søren; Holsgaard-Larsen, Anders

2014-01-01

neuromuscular exercise prior to total joint arthroplasty (TJA) of the hip or knee did not confer additional benefits 3 months postoperatively compared with TJA alone. However, the intervention group experienced a statistically significant short-term benefit in ADL and pain, suggesting an earlier onset......OBJECTIVE: To investigate the postoperative efficacy of a supervised programme of neuromuscular exercise prior to hip or knee arthroplasty. METHODS: In this assessor-blinded randomised controlled trial, we included 165 patients scheduled for hip or knee arthroplasty due to severe osteoarthritis (OA......). An 8-week preoperative neuromuscular supervised exercise programme was delivered twice a week for 1 h as adjunct treatment to the standard arthroplasty procedure and compared with the standard arthroplasty procedure alone. The primary outcome was self-reported physical function measured...

Fas ligand exists on intervertebral disc cells: a potential molecular mechanism for immune privilege of the disc.

Science.gov (United States)

Takada, Toru; Nishida, Kotaro; Doita, Minoru; Kurosaka, Masahiro

2002-07-15

Rat and human intervertebral disc specimens were examined immunohistochemically. Reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed on rat disc tissue to demonstrate the existence of Fas ligand. To clarify the existence of Fas ligand on intact intervertebral disc cells. The nucleus pulposus has been reported to be an immune-privileged site. The immune-privileged characteristic in other tissues such as the retina and testis has been attributed to the local expression of Fas ligand, which acts by inducing apoptosis of invading Fas-positive T-cells. The existence of Fas ligand in normal disc cells has not yet been addressed. Skeletally mature SD male rats were killed, and the coccygeal discs were harvested. Human disc specimens were obtained from idiopathic scoliosis patients during surgical procedures. Immunohistochemical staining for Fas ligand was performed for cross-sections of the discs by standard procedures. Reverse transcription polymerase chain reaction analysis was also carried out to demonstrate Fas ligand mRNA expression on rat intervertebral discs. Testes of the rats were used for positive controls, and muscles were used for negative controls. The sections were observed by light microscopy. The nucleus pulposus cells exhibited intense positive immune staining for Fas ligand. The outer anulus fibrosus cells and notochordal cells exhibited little immunopositivity. The positive controls exhibited positive immune staining, and the negative control showed no immunopositivity. The result of RT-PCR confirmed the existence of Fas ligand in disc cells. The human nucleus pulposus cells showed a similar predilection to rat disc cells. We demonstrated the existence of Fas ligand on disc cells, which should play a key role in the potential molecular mechanism to maintain immune privilege of the disc. Immune privilege and Fas ligand expression of the intervertebral disc may provide a new insight for basic science research as well as

Humeral windows in revision total elbow arthroplasty.

Science.gov (United States)

Peach, Chris A; Salama, Amir; Stanley, David

2016-04-01

The use of cortical windows for revision elbow arthroplasty has not previously been widely reported. Their use aids safe revision of a well fixed humeral prosthesis and can be used in the setting of dislocation, periprosthetic fracture or aseptic loosening of the ulnar component. We describe our technique and results of cortical windows in the distal humerus for revision elbow arthroplasty surgery.

Distraction arthroplasty with arthroscopic microfracture in a patient with rheumatoid arthritis of the ankle joint.

Science.gov (United States)

Nakasa, Tomoyuki; Adachi, Nobuo; Kato, Tomohiro; Ochi, Mitsuo

2015-01-01

We treated a 39-year-old female who had experienced destruction of her ankle joint owing to rheumatoid arthritis. This relatively young patient wished to avoid ankle fusion and joint replacement. Therefore, distraction arthroplasty with arthroscopic microfracture was performed to improve her symptoms and preserve motion. A microfracture procedure specifically for cartilage defects of the tibial plafond and talar dome was performed with the arthroscope, after which a hinged external fixator was applied to distract the ankle joint. The ankle joint space was enlarged by the external device and joint movement allowed. After 3 months, removal of the external device and repeat arthroscopy revealed newly formed fibrocartilage on the surfaces of both the tibia and the talus. At 2 years after the surgery, a radiograph showed that the joint space enlargement of the ankle had been maintained. The American Orthopaedic Foot and Ankle Society score improved from 37 points preoperatively to 82 points at 2 years postoperatively. Our findings suggest that good clinical results can be achieved with distraction arthroplasty and arthroscopic microfracture in a relatively young patient with rheumatoid arthritis. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

Science.gov (United States)

Lee, Jong Eun; Sung, Kyung Rim; Park, Ji Min; Yoon, Joo Young; Kang, Sung Yong; Park, Sung Bae; Koo, Hyung Jin

2017-03-01

To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia. Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD. Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7 years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.

A randomised controlled trial of total hip arthroplasty versus resurfacing arthroplasty in the treatment of young patients with arthritis of the hip joint.

Science.gov (United States)

Achten, Juul; Parsons, Nick R; Edlin, Richard P; Griffin, Damian R; Costa, Matthew L

2010-01-14

Hip replacement (arthroplasty) surgery is a highly successful treatment for patients with severe symptomatic arthritis of the hip joint. For older patients, several designs of Total Hip Arthroplasty have shown excellent results in terms of both function and value for money. However, in younger more active patients, there is approximately a 50% failure rate at 25 years for traditional implants. Hip resurfacing is a relatively new arthroplasty technique. In a recent review of the literature on resurfacing arthroplasty it was concluded that the short-term functional results appear promising but some potential early disadvantages were identified, including the risk of femoral neck fracture and collapse of the head of the femur. The aim of the current study is to assess whether there is a difference in functional hip scores at one year post-operation between Total Hip Arthroplasty and Resurfacing Arthroplasty. Secondary aims include assessment of complication rates for both procedures as well cost effectiveness. All patients medically fit for surgery and deemed suitable for a resurfacing arthroplasty are eligible to take part in this study. A randomisation sequence will be produced and administered independently. After consenting, all patients will be clinically reviewed and hip function, quality of life and physical activity level will be assessed through questionnaires. The allocated surgery will then be performed with the preferred technique of the surgeon. Six weeks post-operation hip function will be assessed and complications recorded. Three, six and 12 months post-operation hip function, quality of life and physical activity level will be assessed. Additional information about patients' out-of-pocket expenses will also be collected. Current Controlled Trials ISRCTN33354155. UKCLRN portfolio ID 4093.

Reverse hybrid total hip arthroplasty

DEFF Research Database (Denmark)

Wangen, Helge; Havelin, Leif I.; Fenstad, Anne M

2017-01-01

Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty....... Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk...

Retina image–based optic disc segmentation

Directory of Open Access Journals (Sweden)

Ching-Lin Wang

2016-05-01

Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

Distraction Arthroplasty of the Trapeziometacarpal Joint Without Trapeziectomy

Directory of Open Access Journals (Sweden)

Kin Weng Wong

2011-01-01

Conclusion: Our technique (distraction arthroplasty without trapeziectomy preserves bony and adjacent structures. It is easier and quicker than traditional arthroplasties. It serves as another effective and stable method of tendon reconstruction with a less invasive approach. A larger series is needed for further observation of validity of the procedure.

Prognosis of intervertebral disc loss from diagnosis of degenerative disc disease

Science.gov (United States)

Li, S.; Lin, A.; Tay, K.; Romano, W.; Osman, Said

2015-03-01

Degenerative Disc Disease (DDD) is one of the most common causes of low back pain, and is a major factor in limiting the quality of life of an individual usually as they enter older stages of life, the disc degeneration reduces the shock absorption available which in turn causes pain. Disc loss is one of the central processes in the pathogenesis of DDD. In this study, we investigated whether the image texture features quantified from magnetic resonance imaging (MRI) could be appropriate markers for diagnosis of DDD and prognosis of inter-vertebral disc loss. The main objective is to use simple image based biomarkers to perform prognosis of spinal diseases using non-invasive procedures. Our results from 65 subjects proved the higher success rates of the combination marker compared to the individual markers and in the future, we will extend the study to other spine regions to allow prognosis and diagnosis of DDD for a wider region.

Physiological pattern of lumbar disc height

International Nuclear Information System (INIS)

Biggemann, M.; Frobin, W.; Brinckmann, P.

1997-01-01

Purpose of this study is to present a new method of quantifying objectively the height of all discs in lateral radiographs of the lumbar spine and of analysing the normal craniocaudal sequence pattern of lumbar disc heights. Methods: The new parameter is the ventrally measured disc height corrected for the dependence on the angle of lordosis by normalisation to mean angles observed in the erect posture of healthy persons. To eliminate radiographic magnification, the corrected ventral height is related to the mean depth of the cranially adjoining vertebra. In this manner lumbar disc heights were objectively measured in young, mature and healthy persons (146 males and 65 females). The craniocaudal sequence pattern was analysed by mean values from all persons and by height differences of adjoining discs in each individual lumbar spine. Results: Mean normative values demonstrated an increase in disc height between L1/L2 and L4/L5 and a constant or decreasing disc height between L4/L5 and L5/S1. However, this 'physiological sequence of disc height in the statistical mean' was observed in only 36% of normal males and 55% of normal females. Conclusion: The radiological pattern of the 'physiological sequence of lumbar disc height' leads to a relevant portion of false positive pathological results especially at L4/L5. An increase of disc height from L4/L5 to L5/S1 may be normal. The recognition of decreased disc height should be based on an abrupt change in the heights of adjoining discs and not on a deviation from a craniocaudal sequence pattern. (orig.) [de

CT morphometry of adult thoracic intervertebral discs.

Science.gov (United States)

Fletcher, Justin G R; Stringer, Mark D; Briggs, Christopher A; Davies, Tilman M; Woodley, Stephanie J

2015-10-01

Despite being commonly affected by degenerative disorders, there are few data on normal thoracic intervertebral disc dimensions. A morphometric analysis of adult thoracic intervertebral discs was, therefore, undertaken. Archival computed tomography scans of 128 recently deceased individuals (70 males, 58 females, 20-79 years) with no known spinal pathology were analysed to determine thoracic disc morphometry and variations with disc level, sex and age. Reliability was assessed by intraclass correlation coefficients (ICCs). Anterior and posterior intervertebral disc heights and axial dimensions were significantly greater in men (anterior disc height 4.0±1.4 vs 3.6±1.3 mm; posterior disc height 3.6±0.90 vs 3.4±0.93 mm; p<0.01). Disc heights and axial dimensions at T4-5 were similar or smaller than at T2-3, but thereafter increased caudally (mean anterior disc height T4-5 and T10-11, 2.7±0.7 and 5.4±1.2 mm, respectively, in men; 2.6±0.8 and 5.1±1.3 mm, respectively, in women; p<0.05). Except at T2-3, anterior disc height decreased with advancing age and anteroposterior and transverse disc dimensions increased; posterior and middle disc heights and indices of disc shape showed no consistent statistically significant changes. Most parameters showed substantial to almost perfect agreement for intra- and inter-rater reliability. Thoracic disc morphometry varies significantly and consistently with disc level, sex and age. This study provides unique reference data on adult thoracic intervertebral disc morphometry, which may be useful when interpreting pathological changes and for future biomechanical and functional studies.

Disc-halo interactions in ΛCDM

Science.gov (United States)

Bauer, Jacob S.; Widrow, Lawrence M.; Erkal, Denis

2018-05-01

We present a new method for embedding a stellar disc in a cosmological dark matter halo and provide a worked example from a Λ cold dark matter zoom-in simulation. The disc is inserted into the halo at a redshift z = 3 as a zero-mass rigid body. Its mass and size are then increased adiabatically while its position, velocity, and orientation are determined from rigid-body dynamics. At z = 1, the rigid disc (RD) is replaced by an N-body disc whose particles sample a three-integral distribution function (DF). The simulation then proceeds to z = 0 with live disc (LD) and halo particles. By comparison, other methods assume one or more of the following: the centre of the RD during the growth phase is pinned to the minimum of the halo potential, the orientation of the RD is fixed, or the live N-body disc is constructed from a two rather than three-integral DF. In general, the presence of a disc makes the halo rounder, more centrally concentrated, and smoother, especially in the innermost regions. We find that methods in which the disc is pinned to the minimum of the halo potential tend to overestimate the amount of adiabatic contraction. Additionally, the effect of the disc on the subhalo distribution appears to be rather insensitive to the disc insertion method. The LD in our simulation develops a bar that is consistent with the bars seen in late-type spiral galaxies. In addition, particles from the disc are launched or `kicked up' to high galactic latitudes.

The comparative analysis of rocks' resistance to forward-slanting disc cutters and traditionally installed disc cutters

Science.gov (United States)

Zhang, Zhao-Huang; Fei, Sun; Liang, Meng

2016-08-01

At present, disc cutters of a full face rock tunnel boring machine are mostly mounted in the traditional way. Practical use in engineering projects reveals that this installation method not only heavily affects the operation life of disc cutters, but also increases the energy consumption of a full face rock tunnel boring machine. To straighten out this issue, therefore, a rock-breaking model is developed for disc cutters' movement after the research on the rock breaking of forward-slanting disc cutters. Equations of its displacement are established based on the analysis of velocity vector of a disc cutter's rock-breaking point. The functional relations then are brought forward between the displacement parameters of a rock-breaking point and its coordinate through the analysis of micro displacement of a rock-breaking point. Thus, the geometric equations of rock deformation are derived for the forward-slanting installation of disc cutters. With a linear relationship remaining between the acting force and its deformation either before or after the leap breaking, the constitutive relation of rock deformation can be expressed in the form of generalized Hooke law, hence the comparative analysis of the variation in the resistance of rock to the disc cutters mounted in the forward-slanting way with that in the traditional way. It is discovered that with the same penetration, strain of the rock in contact with forward-slanting disc cutters is apparently on the decline, in other words, the resistance of rock to disc cutters is reduced. Thus wear of disc cutters resulted from friction is lowered and energy consumption is correspondingly decreased. It will be useful for the development of installation and design theory of disc cutters, and significant for the breakthrough in the design of full face rock tunnel boring machine.

Comparison of cemented and uncemented fixation in total knee arthroplasty.

Science.gov (United States)

Brown, Thomas E; Harper, Benjamin L; Bjorgul, Kristian

2013-05-01

As a result of reading this article, physicians should be able to :1. Understand the rationale behind using uncemented fixation in total knee arthroplasty.2.Discuss the current literature comparing cemented and uncemented total knee arthroplasty3. Describe the value of radiostereographic analysis in assessing implant stability.4. Appreciate the limitations in the available literature advocating 1 mode of fixation in total knee arthroplasty. Total knee arthroplasty performed worldwide uses either cemented, cementless, or hybrid (cementless femur with a cemented tibia) fixation of the components. No recent literature review concerning the outcomes of cemented vs noncemented components has been performed. Noncemented components offer the potential advantage of a biologic interface between the bone and implants, which could demonstrate the greatest advantage in long-term durable fixation in the follow-up of young patients undergoing arthroplasty. Several advances have been made in the backing of the tibial components that have not been available long enough to yield long-term comparative follow-up studies. Short-term radiostereographic analysis studies have yielded differing results. Although long-term, high-quality studies are still needed, material advances in biologic fixation surfaces, such as trabecular metal and hydroxyapatite, may offer promising results for young and active patients undergoing total knee arthroplasty when compared with traditional cemented options. Copyright 2013, SLACK Incorporated.

MR-fluid yield surface determination in disc-type MR rotary brakes

International Nuclear Information System (INIS)

Farjoud, Alireza; Vahdati, Nader; Fah, Yap Fook

2008-01-01

Magneto-rheological (MR) fluids are currently attracting a great deal of attention because of their unique rheological behavior. Many devices have been designed using MR fluids, and of potential interest here are disc-type MR rotary brakes. The plug flow region in MR devices is defined as the region where the fluid is not flowing. The plug flow region plays an important role in design and analysis of MR devices. In MR dampers, the damping coefficient is a function of the plug thickness. In MR valves, the plug thickness is used to control the flow rate through, and the pressure drop across, the MR valve. A MR clutch is performing at the highest efficiency when the entire MR gap is the plug region. For an MR rotary brake, the highest restraining torque is obtained when the entire gap is the plug region as far as there are no wall slip effects. In this paper, using the Bercovier and Engelman constitutive model, the MR fluid flow in disc-type MR brakes is modeled to determine the plug flow region. The resulting system of equations is solved numerically. It is shown that the existence of a plug flow region in the brake will affect the control torque ratio. Better estimation of the plug flow region results in better estimation of the viscous torque

A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

2004-01-01

Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...... for making the design of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs with surface defects is presented. The main novel element in the model is a model of the surface defects. That model is based on data from discs with surface defects. This model...

Patient-reported outcome measures in arthroplasty registries

DEFF Research Database (Denmark)

Rolfson, Ola; Bohm, Eric; Franklin, Patricia

2016-01-01

The International Society of Arthroplasty Registries (ISAR) Patient-Reported Outcome Measures (PROMs) Working Group have evaluated and recommended best practices in the selection, administration, and interpretation of PROMs for hip and knee arthroplasty registries. The 2 generic PROMs in common use...... are the Short Form health surveys (SF-36 or SF-12) and EuroQol 5-dimension (EQ-5D). The Working Group recommends that registries should choose specific PROMs that have been appropriately developed with good measurement properties for arthroplasty patients. The Working Group recommend the use of a 1-item pain...... should consider the absolute level of pain, function, and general health status as well as improvement, missing data, approaches to analysis and case-mix adjustment, minimal clinically important difference, and minimal detectable change. The Working Group recommends data collection immediately before...

Reduced survival for uncemented compared to cemented total hip arthroplasty after operatively treated acetabular fractures.

Science.gov (United States)

Clarke-Jenssen, John; Westberg, Marianne; Røise, Olav; Storeggen, Stein Arne Øvre; Bere, Tone; Silberg, Ingunn; Madsen, Jan Erik

2017-11-01

Post traumatic arthritis and avascular necrosis of the femoral head are common complications after operatively treated acetabular fractures. This may cause severe disabilities for the patient, necessitating a total hip arthroplasty. Even though an arthroplasty may provide good symptomatic relief, the long-term results are more uncertain and no consensus exists according to preferred prosthetic designs. With this cohort study, we aimed to investigate the medium to long term arthroplasty survival and clinical results of total hip arthroplasty after operatively treated acetabular fractures. We included 52 patients treated with a secondary total hip arthroplasty at a median of 2.4 (0.1-14.1) years after an operatively treated acetabular fracture. The median age was 54 (11-82) years. Cemented arthroplasty was used for 33 patients, 10 patients had an uncemented arthroplasty and 9 patients received a hybrid arthroplasty. Average follow up was 8.0 (SD 5.0) years. Ten-year revision free arthroplasty survival was 79%. Uncemented arthroplasties had a significantly worse 10-year survival of 57%. Arthroplasties performed at a centre without a pelvic fracture service also had a significantly worse 10-years survival of 51%. Cox regression showed similar results with an 8-fold increase in risk of revision for both uncemented arthroplasties and operations performed at a non-pelvic trauma centre. Total hip arthroplasty secondary to an operatively treated acetabular fracture provides good symptomatic relief. These patients are, however, complex cases and are probably best treated at specialist centres with both pelvic trauma surgeons and arthroplasty surgeons proficient in complex revisions present. Copyright © 2017 Elsevier Ltd. All rights reserved.

MR image assessment of disc configuration and degree of anterior disc displacement in internal derangement related to age

International Nuclear Information System (INIS)

Igarashi, Chinami; Kobayashi, Kaoru; Imanaka, Masahiro; Yuasa, Masao; Yamamoto, Akira

1999-01-01

This study was designed to evaluate the configuration of the articular disc and degree of anterior disc displacement on magnetic resonance (MR) imagings in temporomandibular joints (TMJs) with internal derangement. A total of 363 joints diagnosed as having anterior disc displacement with reduction (ADD w R) and 523 joints diagnosed as having anterior disc displacement without reduction (ADD wo R) by MR imaging were examined. These joints did not show severe osseous changes on the condylar head or glenoid fossa. We assessed the configuration of the articular disc and degree of anterior disc displacement. In the ADD w R group, 82.6% of the articular discs showed biconcave configuration; enlargement of the posterior band in 4.6%, biconvex configuration in 0.5%, and others in 10.7%. Moreover 62.5% of the discs showed a slight degree of anterior disc displacement; were 27.2% moderately displaced and were 10.2% severe displaced. The prevalence of slightly displaced discs was higher in the TMJs of cases over 50 years of age than in cases under 30 years in the ADD w R group. On the other hand, in the ADD wo R group 35.9% of the articular discs showed biconcave configuration; enlargement of the posterior band in 12.6%, biconvex configuration in 25.4%, and others in 22.3%. Furthermore, 4.4% of the discs were slightly displaced; 43.9% moderately displaced and 51.6% were severely displaced. The prevalence of severely displaced and deformed discs in joints of cases over 40 years of age was high in the ADD wo R group. The prevalence of slightly displaced biconcave discs was higher in the ADD w R group. The other hand, the prevalence of severely displaced deformed discs was higher in the ADD wo R group. MR findings of internal derangement of the TMJ were found to be significantly correlated with age. (author)

Outcomes of an anatomic total shoulder arthroplasty with a contralateral reverse total shoulder arthroplasty.

Science.gov (United States)

Cox, Ryan M; Padegimas, Eric M; Abboud, Joseph A; Getz, Charles L; Lazarus, Mark D; Ramsey, Matthew L; Williams, Gerald R; Horneff, John G

2018-06-01

It is common for patients to require staged bilateral shoulder arthroplasties. There is a unique cohort of patients who require an anatomic total shoulder arthroplasty (TSA) and a contralateral reverse shoulder arthroplasty (RSA). This study compared the outcomes of patients with a TSA in 1 shoulder and an RSA in the contralateral shoulder. Our institutional database was queried to identify all patients with a TSA and a contralateral RSA. Data collection included patient demographics, preoperative and latest follow-up shoulder range of motion, radiographic analysis, and postoperative complications. Identified patients were assessed at follow-up visits or contacted by phone for functional outcome scores. Nineteen patients met our inclusion/exclusion criteria. There was statistically significant greater internal rotation in the TSA shoulder (P= .044) but no significant difference in forward elevation (P = .573) or external rotation (P= .368). There was no radiographic evidence of humeral or glenoid component loosening of any arthroplasty implants. There were no significant differences between TSA and RSA shoulders for the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment (P= .381), Simple Shoulder Test (P = .352), Single Assessment Numerical Evaluation (P = .709), and visual analog scale satisfaction (P= .448) or pain scores (P= .305). Thirteen patients (68.4%) preferred the RSA side, 1 patient (5.3%; z = 4.04, P < .001) patient preferred the TSA side, and 5 patients expressed no preference. Despite known limitations and differences between TSA and RSA designs, patients who have received both implants are highly satisfied with both. The only parameter in which the TSA had superior outcomes was internal rotation. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

ChromiSense: A colourimetric lab-on-a-disc sensor for chromium speciation in water.

Science.gov (United States)

Duffy, G; Maguire, I; Heery, Brendan; Gers, Pauline; Ducrée, J; Regan, F

2018-02-01

The development of a centrifugal device for quantitative analysis of both chromium (III) and (VI) species in water is reported. ChromiSense is a colourimetric sensor system that has been applied to the measurement of chromium in spiked river water samples. For analysis, the sample is loaded into a reservoir on the disposable microfluidic disc, along with reagents. A centrifugal force is created by spinning the disc to pump liquids through microchannels, causing them to mix and react to form a coloured product. The coloured product is then presented to a low-cost optical detection system, where absorbance measurements can be recorded. The optical detection system consists of a light emitting diode (LED) and photodiode (PD) couple. Chromium (III) was measured using 2,6-pyridine dicarboxylic acid as a ligand, forming a complex that was measured at 535nm and at 335nm. While measuring at 535nm allowed for the use of a low cost LED, the sensitivity was improved 2.5 times by measuring at 335nm. However, 335nm also yielded a diminished linear range with little improvement in limit of deteciton (LOD), and required a lengthier manufacturing process due to the need for a UV-transparent material. Chromium (VI) was detected using 1,5-diphenyl carbazide (DPC). This standard analysis method was simplified for automation on-disc, and optimised to achieve a low LOD. The LOD for trivalent and hexavalent chromium using this device were 21mgL -1 and 4μgL -1 , respectively. The linear range for quantitative analysis was found to be 69-1000mgL -1 for Cr(III) and 14-1000μgL -1 for Cr (VI). While this range is high for Cr(III), incorporation of an off-disc pre-concentration method would make this technology suitable for environmental sample analysis. The device is simple to use, low in cost, and could provide rapid on-site measurements, with results comparable to those obtained using a benchtop spectrophotometer. Copyright © 2017 Elsevier B.V. All rights reserved.

Knee arthroplasty and bleeding: when to remove drainages.

Science.gov (United States)

Ares, Oscar; Seijas, Roberto; Hernandez, Alberto; Castellet, Enric; Sallent, Andrea

2013-02-01

The aim of this study is an attempt to clarify the productive time of drainages as we find that the use of drains in knee arthroplasty is controversial, and there is no consensus regarding their length-time maintenance. We analysed the survival curve of bleeding within three surgical techniques for knee arthroplasty and the effect of two variables on survival curve. One hundred and eighty-eight out of 234 knees were included in the study, and patients were divided into three groups according to the surgical technique: conventional total knee arthroplasty (TKA), subvastus TKA and unicompartmental knee arthroplasty. Variables of study were type of surgery, number and placement of drains. Mean of survival curve for postoperative bleeding time was 16 h (95 % CI: 15.4; 16.6). The risk for longer bleeding increased 1.38-fold with each additional drain used (95 % CI 1.1; 1.8). According to the present study, drains can be safely removed at around 17 h postoperative. Bleeding time reduces as less drains are applied. Therapeutic study, Level III.

Lumbar disc excision through fenestration

Directory of Open Access Journals (Sweden)

Sangwan S

2006-01-01

Full Text Available Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases. Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method. Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value< 0.001, paired t test. No significant complications were recorded. Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

Semiconductor-based, large-area, flexible, electronic devices on {110} oriented substrates

Science.gov (United States)

Goyal, Amit

2014-08-05

Novel articles and methods to fabricate the same resulting in flexible, oriented, semiconductor-based, electronic devices on {110} textured substrates are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

[100] or [110] aligned, semiconductor-based, large-area, flexible, electronic devices

Science.gov (United States)

Goyal, Amit

2015-03-24

Novel articles and methods to fabricate the same resulting in flexible, large-area, [100] or [110] textured, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

Metrical analysis of disc-condyle relation with different splint treatment positions in patients with TMJ disc displacement

Directory of Open Access Journals (Sweden)

Mu-Qing Liu

Full Text Available Abstract Objective: To evaluate the effect of bite positions characterizing different splint treatments (anterior repositioning and stabilization splints on the disc-condyle relation in patients with TMJ disc displacement with reduction (DDwR, using magnetic resonance imaging (MRI. Material and Methods: 37 patients, with a mean age of 18.8±4.3 years (7 male and 30 females and diagnosed with DDwR based on the RDC/TMD, were recruited. MRI metrical analysis of the spatial changes of the disc/condyle, as well as their relationships, was done in three positions: maximum intercuspation (Position 1, anterior repositioning splint position (Position 2, and stabilization splint position (Position 3. Disc/condyle coordinate measurements and disc condyle angles were determined and compared. Results: In Position 1, the average disc-condyle angle was 53.4° in the 60 joints with DDwR, while it was −13.3° with Position 2 and 30.1° with Position 3. The frequency of successful "disc recapture" with Position 2 was significantly higher (58/60, 96.7% than Position 3 (20/60, 33.3%. In Positions 2 and 3, the condyle moved forward and downward while the disc moved backward. The movements were, however, more remarkable with Position 2. Conclusions: Anterior repositioning of the mandible improves the spatial relationship between the disc and condyle in patients with DDwR. In addition to anterior and inferior movement of the condyle, transitory posterior movement of the disc also occurred.

Should gram stains have a role in diagnosing hip arthroplasty infections?

Science.gov (United States)

Johnson, Aaron J; Zywiel, Michael G; Stroh, D Alex; Marker, David R; Mont, Michael A

2010-09-01

The utility of Gram stains in diagnosing periprosthetic infections following total hip arthroplasty has recently been questioned. Several studies report low sensitivity of the test, and its poor ability to either confirm or rule out infection in patients undergoing revision total hip arthroplasty. Despite this, many institutions including that of the senior author continue to perform Gram stains during revision total hip arthroplasty. We assessed the sensitivity, specificity, accuracy, and positive and negative predictive values of Gram stains from surgical-site samplings taken from procedures on patients with both infected and aseptic revision total hip arthroplasties. A review was performed on patients who underwent revision total hip arthroplasty between 2000 and 2007. Eighty-two Gram stains were performed on patients who had infected total hip arthroplasties and underwent revision procedures. Additionally, of the 410 revision total hip arthroplasties performed on patients who were confirmed infection-free, 120 Gram stains were performed. Patients were diagnosed as infected using multiple criteria at the time of surgery. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated from these Gram stain results. The Gram stain demonstrated a sensitivity and specificity of 9.8% and 100%, respectively. In this series, the Gram stain had a negative predictive value of 62%, a positive predictive value of 100%, and an accuracy of 63%. Gram stains obtained from surgical-site samples had poor sensitivity and poor negative predictive value. Based on these findings, as well as those of other authors, we believe that Gram stains should no longer be considered for diagnosing infections in revision total hip arthroplasty. Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

High risk for revision after shoulder arthroplasty for failed osteosynthesis of proximal humeral fractures

DEFF Research Database (Denmark)

Kristensen, Marc Randall; Rasmussen, Jeppe Vejlgaard; Elmengaard, Brian

2018-01-01

Background and purpose - It is unclear whether previous osteosynthesis is a risk factor for inferior outcome following shoulder arthroplasty for a proximal humeral fracture. We used data from the Danish Shoulder Arthroplasty Registry (DSR) to examine this question. Patients and methods - All 285...... patients treated with a shoulder arthroplasty after failed osteosynthesis of a proximal humeral fracture reported to DSR from 2006 to 2013 were included. Each case was matched with 2 controls (570) treated with a primary shoulder arthroplasty for an acute proximal humeral fracture. Patient reported outcome...... for a shoulder arthroplasty after failed osteosynthesis was 2 with a primary arthroplasty for fracture as reference. In a separate analysis of patients treated by locking plate the mean WOOS was 46 (24), with a relative risk of revision at 1.5 with a primary arthroplasty as reference. Interpretation - Compared...

Disc Golf: Teaching a Lifetime Activity

Science.gov (United States)

Eastham, Susan L.

2015-01-01

Disc golf is a lifetime activity that can be enjoyed by students of varying skill levels and abilities. Disc golf follows the principles of ball golf but is generally easier for students to play and enjoy success. The object of disc golf is similar to ball golf and involves throwing a disc from the teeing area to the target in as few throws as…

Endovascular Management of Recurrent Spontaneous Hemarthrosis After Arthroplasty

International Nuclear Information System (INIS)

Kolber, Marcin K.; Shukla, Pratik A.; Kumar, Abhishek; Zybulewski, Adam; Markowitz, Todd; Silberzweig, James E.

2017-01-01

PurposeRecurrent spontaneous hemarthrosis is an infrequent but debilitating late complication of joint replacement, affecting up to 1.6% of patients with arthroplasty of the affected joint. Repeated episodes of bleeding result in an inflammatory cascade that further propagates bleeding events. Open and arthroscopic synovectomy are often performed when conservative treatments fail. Transarterial embolization is increasingly utilized as a less invasive option; however, its role is not widely established. We performed a systematic literature review to report the safety and efficacy of transarterial embolization in treating recurrent hemarthrosis in the setting of prior arthroplasty.Materials and MethodsA systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. A structured search was performed in PubMed, Web of Science, Embase, and SCOPUS databases of patients undergoing embolization for recurrent hemarthrosis after arthroplasty. Patients immediately post-operative, those embolized at first bleeding episode, and those with hemophilia were excluded. Demographic data, clinical information, angiographic findings, treatment, and outcomes were tabulated.ResultsThe search identified 119 titles of which 24 were deemed relevant, comprising 91 patients undergoing 99 embolization procedures. Mean time from prosthesis implantation was 32.2 months. Technical success was 99%. Mean follow-up time was 24.9 months. There were 10 recurrences (10%). Two cases were complicated by joint infection requiring arthroplasty revision.ConclusionsTransarterial embolization for recurrent spontaneous hemarthrosis may be safe and effective in patients having undergone arthroplasty of the affected joint.

Endovascular Management of Recurrent Spontaneous Hemarthrosis After Arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Kolber, Marcin K.; Shukla, Pratik A.; Kumar, Abhishek; Zybulewski, Adam; Markowitz, Todd; Silberzweig, James E., E-mail: jsilberzweig@chpnet.org [Mount Sinai Beth Israel, Division of Vascular and Interventional Radiology, Department of Radiology (United States)

2017-02-15

PurposeRecurrent spontaneous hemarthrosis is an infrequent but debilitating late complication of joint replacement, affecting up to 1.6% of patients with arthroplasty of the affected joint. Repeated episodes of bleeding result in an inflammatory cascade that further propagates bleeding events. Open and arthroscopic synovectomy are often performed when conservative treatments fail. Transarterial embolization is increasingly utilized as a less invasive option; however, its role is not widely established. We performed a systematic literature review to report the safety and efficacy of transarterial embolization in treating recurrent hemarthrosis in the setting of prior arthroplasty.Materials and MethodsA systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. A structured search was performed in PubMed, Web of Science, Embase, and SCOPUS databases of patients undergoing embolization for recurrent hemarthrosis after arthroplasty. Patients immediately post-operative, those embolized at first bleeding episode, and those with hemophilia were excluded. Demographic data, clinical information, angiographic findings, treatment, and outcomes were tabulated.ResultsThe search identified 119 titles of which 24 were deemed relevant, comprising 91 patients undergoing 99 embolization procedures. Mean time from prosthesis implantation was 32.2 months. Technical success was 99%. Mean follow-up time was 24.9 months. There were 10 recurrences (10%). Two cases were complicated by joint infection requiring arthroplasty revision.ConclusionsTransarterial embolization for recurrent spontaneous hemarthrosis may be safe and effective in patients having undergone arthroplasty of the affected joint.

[Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

Science.gov (United States)

Guder, E; Hill, S; Kandziora, F; Schnake, K J

2009-01-01

The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

Fast-track knee arthroplasty – status and future challenges

DEFF Research Database (Denmark)

Kehlet, Henrik; Thienpont, Emmanuel

2013-01-01

Fast-track programs have been developed for different surgical procedures leading to higher patient satisfaction and lower morbidity. This concept has been extended to knee arthroplasty in recent years. The purpose of this narrative review was to discuss the different aspects of fast-track knee...... arthroplasty....

Radiological assessment of loss of disc height during acute and chronic degenerative lumbar disc alterations

International Nuclear Information System (INIS)

Zoellner, J.; Sancaktaroglu, T.; Nafe, B.; Eysel, P.; Loew, R.

2001-01-01

Aim of the study: A loss of disc height with increasing segmental mobility is an important reason for low back pain. The measurement of hyaluronic acid content of the nucleus pulposus prolaps shows a difference between acute (group 1) and chronic (group 2) disc degeneration. The purpose of the present investigation was to determine the decreasing of disc height between these two groups and the no-symptomatic segments of these patients. Methods: 20 human lateral preoperative X-ray measurements according to Frobin et al. were taken; group 1 with 7 patients (mean age 41 years) and group 2 with 13 patients (mean age 44 years). Results: There was a significant tendency (p=0.091) to a reduction of disc height in group 2 between symptomatic and asymptomatic discs. Conclusion: The used method is not suitable to answer the present question conclusively. (orig.) [de

Actuator disc edge singularity. The key to a revised actuator disc concept and momentum theory

Energy Technology Data Exchange (ETDEWEB)

Kuik, G.A.M. van (The Wind Energy Group of the Technical University Eindhoven (NL))

1989-01-01

Since the beginning of rotor aerodynamics the actuator disc momentum theory occupies a prominant place in almost any textbook on this subject. Specially in axial flow the theory provides an easy and rather accurate performance prediction. The results first obtained by Lanchester for the induced power of a hovering rotor and the maximum power of a wind turbine are still used as guidelines for complicated calculations. On the other hand, experimental results for propellers are known to deviate systematically (some 10%) from the momentum theory results. This is commonly attributed to the differences between a real rotor and an actuator disc. However, some actuator disc- and actuator strip (the 2-dimensional version) experiments are described in literature, showing the same deviations from momentum theory results. Therefore, apart from the question how representative an actuator disc is for a real rotor, the actuator disc concept itself may be inadequate. This problem is the subject of the work describe here. It will be shown that the classical actuator disc concept ignores discrete forces resulting from a flow singularity at the edge of the disc. The (extended) momentum theory, applied to this actuator strip model, shows a shift of the results towards the experimental data, and for the static case (hover) even a quantitative agreement is obtained. (author) 12 refs.

Vascular complications of prosthetic inter-vertebral discs.

Science.gov (United States)

Daly, Kevin J; Ross, E Raymond S; Norris, Heather; McCollum, Charles N

2006-10-01

Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had eroded into the bifurcation of the inferior vena cava and the left common iliac vein. In three cases the aortic bifurcation was also involved. The fibrosis was so severe that dissecting out the arteries and veins to provide access to the relevant disc proved impossible. Formal division of the left common iliac vein and artery with subsequent repair was our solution. Anterior inter-vertebral disc displacement was associated with severe vascular injury. Preventing anterior disc displacement is essential in disc design. In the event of anterior displacement, disc removal should be planned with a Vascular Surgeon.

Deep-down ionization of protoplanetary discs

Science.gov (United States)

Glassgold, A. E.; Lizano, S.; Galli, D.

2017-12-01

The possible occurrence of dead zones in protoplanetary discs subject to the magneto-rotational instability highlights the importance of disc ionization. We present a closed-form theory for the deep-down ionization by X-rays at depths below the disc surface dominated by far-ultraviolet radiation. Simple analytic solutions are given for the major ion classes, electrons, atomic ions, molecular ions and negatively charged grains. In addition to the formation of molecular ions by X-ray ionization of H2 and their destruction by dissociative recombination, several key processes that operate in this region are included, e.g. charge exchange of molecular ions and neutral atoms and destruction of ions by grains. Over much of the inner disc, the vertical decrease in ionization with depth into the disc is described by simple power laws, which can easily be included in more detailed modelling of magnetized discs. The new ionization theory is used to illustrate the non-ideal magnetohydrodynamic effects of Ohmic, Hall and Ambipolar diffusion for a magnetic model of a T Tauri star disc using the appropriate Elsasser numbers.

Physiotherapy-led arthroplasty review clinic: a preliminary outcomes analysis.

Science.gov (United States)

Large, Kate E; Page, Carolyn J; Brock, Kim; Dowsey, Michelle M; Choong, Peter F M

2014-11-01

With the rising demand for Orthopaedics in the healthcare sector, service delivery innovations need to be explored to accommodate the increasing workload. Senior Musculoskeletal Physiotherapists have the specialised skills in the assessment of musculoskeletal conditions to determine the impact of surgery on patient outcomes. The aim of the present study was to compare outcomes between a physiotherapy-led arthroplasty review clinic (PT clinic) and the traditional model of orthopaedic surgeon review (OS clinic) after hip and knee replacement. This study was a retrospective case-controlled audit using a comprehensive database. Twenty-four patients who had a hip arthroplasty and 52 patients who had a knee arthroplasty were reviewed solely by the PT clinic at 3, 6 and 12 months after surgical reviews. These patients were matched 1:2 against patients seen only by the OS clinic. The outcome measures included International Knee Score (IKS), Harris Hip Score (HHS) and the Short Form (SF)-12. There were no significant differences in HHS or SF-12 scores for patients after hip arthroplasty. Significant differences for knee arthroplasty were observed favouring the PT clinic; IKS, PT clinic 147.6 (37.07), OS clinic 135.4 (35.68), P≤0.01, and physical component of the SF-12, PT clinic 41.98 (10.45), OS clinic 37.20 (10.44), Pphysiotherapy-led arthroplasty review clinic appears to be a safe and effective service alternative to reviews conducted by orthopaedic surgeons. WHAT IS KNOWN ABOUT THE TOPIC?: Osteoarthritis (OA) is a leading cause of musculoskeletal pain and disability and the burden of the disease is rapidly increasing. Joint arthroplasty surgery is the mainstay of treatment for people with end-stage OA; it is a high-cost, high-volume procedure that dominates surgical wait lists around Australia. Long-term follow up is encouraged by the Arthroplasty Society of Australia and endorsed by the Australian Orthopaedics Association, but it is acknowledged that it is impossible

Shoulder arthroplasty. Part 1: Prosthesis terminology and classification

International Nuclear Information System (INIS)

Sheridan, B.D.; Ahearn, N.; Tasker, A.; Wakeley, C.; Sarangi, P.

2012-01-01

Shoulder arthroplasty is the third most common joint replacement procedure in the UK, and there are a number of different implant options available to surgeons to treat a variety of shoulder disorders. With an increasing burden placed on clinical follow-up, more patients are remaining under the care of their general practitioners and musculoskeletal triage assessment services and are not necessarily being seen by specialists. Referrals to orthopaedic specialists are therefore often prompted by radiological reports describing evidence of implant failure. This article is the first of two reviews on shoulder arthroplasty, concentrating on implant features and the indications for their use. The second article will address the modes of failure of shoulder arthroplasty and describe the relevant associated radiological features.

Shoulder arthroplasty. Part 1: Prosthesis terminology and classification

Energy Technology Data Exchange (ETDEWEB)

Sheridan, B.D., E-mail: bdsheridan@hotmail.com [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom); Ahearn, N.; Tasker, A.; Wakeley, C.; Sarangi, P. [Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol (United Kingdom)

2012-07-15

Shoulder arthroplasty is the third most common joint replacement procedure in the UK, and there are a number of different implant options available to surgeons to treat a variety of shoulder disorders. With an increasing burden placed on clinical follow-up, more patients are remaining under the care of their general practitioners and musculoskeletal triage assessment services and are not necessarily being seen by specialists. Referrals to orthopaedic specialists are therefore often prompted by radiological reports describing evidence of implant failure. This article is the first of two reviews on shoulder arthroplasty, concentrating on implant features and the indications for their use. The second article will address the modes of failure of shoulder arthroplasty and describe the relevant associated radiological features.

Does advanced cryotherapy reduce pain and narcotic consumption after knee arthroplasty?

Science.gov (United States)

Thienpont, Emmanuel

2014-11-01

Cryotherapy has been used to enhance recovery after orthopaedic surgery. Several cooling devices are available but few can guarantee a fixed temperature during a prolonged time and therefore have been criticized. The arrival of new advanced cryotherapy devices made it possible to test the effect of prolonged cooling on rehabilitation after joint replacement. The hypotheses of this randomized controlled trial (RCT) were that advanced cryotherapy devices compared with cold packs result in (1) better postoperative pain control resulting in a lower consumption of narcotics; (2) better early ROM; and (3) less postoperative bleeding and swelling. A priori sample size calculation had determined that to detect a difference of 2 points on the VAS, a sample size of 50 subjects per group at followup would be required, given a study power of 80%. One hundred sixteen patients were included and randomly allocated to receive advanced cryotherapy (n=58) or use of cold packs (n=58). The primary outcomes for the study were to evaluate pain with the VAS and analgesics consumption. Secondary outcomes were postoperative ROM, swelling, and blood loss. One hundred (50 in each group) patients had complete data available for analysis. No statistically significant differences in VAS, need for analgesics, nor in secondary outcomes were observed, except for substantially reduced flexion at 6 weeks in the advanced cryotherapy group (114° versus 120°). Advanced cryotherapy with a continuous temperature for a prolonged period does not deliver expected results of superior early recovery after knee arthroplasty. Greater sample sizes are required to fully determine significant differences between the two techniques for these study parameters. Immobilization of the knee in extension during the prolonged cryotherapy session resulted in lower active flexion at 6 weeks after surgery for the advanced cryotherapy group. Advanced cryotherapy should not be used in fast track knee arthroplasty if the

Comparison of Heidelberg Retina Tomograph with disc-macula distance to disc diameter ratio in diagnosing optic nerve hypoplasia.

Science.gov (United States)

Pang, Yi; Frantz, Kelly A

2016-05-01

To evaluate whether Heidelberg Retinal Tomograph (HRT) is a valid test for diagnosing congenital optic nerve hypoplasia (CONH) compared to the ratio of the distance between the centre of the optic disc and the centre of the macula and the mean optic disc diameter (DM:DD ratio). Furthermore, to determine the optimal cut-off value of HRT disc area to differentiate a hypoplastic disc from a normal optic disc. A total of 33 subjects with CONH (4-67 years old) and 160 normal subjects (5-65 years old) were recruited and underwent comprehensive eye examinations, fundus photography and HRT. Receiver operating characteristic curves for DM:DD ratio and HRT disc area were constructed based on data from the 46 CONH eyes and 160 control eyes. Mean (±S.D.) HRT disc area was 1.94 (±0.54) mm(2) for the control eyes and 0.84 (±0.35) mm(2) for the CONH eyes (p < 0.0001). The area under the curve (AUC) for DM:DD ratio was 0.83 (95% confidence interval: 0.76-0.90). The AUC for HRT disc area was 0.96 (95% confidence interval: 0.94-0.99). A statistically significant difference was found between AUC for HRT disc area and that for DM:DD ratio (p = 0.0004). The optimal cut-off value for HRT disc area was 1.42 mm(2) with 95% sensitivity and 85% specificity. The optimal cut-off value for DM:DD ratio was 3.20 with 78% sensitivity and 78% specificity. Both HRT and the DM:DD ratio are valid tests to aid diagnosis of CONH. HRT is superior to DM:DD ratio in diagnosing CONH with higher sensitivity and specificity. We suggest the optimal cut-off value for HRT disc area as 1.42 mm(2) in order to discriminate a hypoplastic disc from a normal optic disc. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

CT findings of lumbar intervertebral disc: II. Disc herniation (HNP)

International Nuclear Information System (INIS)

Yang, W. J.; Lee, J. M.; Bahk, Y. W.

1984-01-01

In lumbar region the epidural fat pad is relatively abundant so that CT can provides sufficient information in diagnosis of lumbar HNP. Many authors have reported on the CT findings of HNP such as focal nodular protrusion of the posterior disc margin, obliteration of epidural fat pad, impingement of dural sac and nerve root, swelling of nerve root, soft tissue density in the spinal canal and calcification of disc. However there was so previous report describing incidence and reliability of the findings. It is the purpose of the present study to survey the frequency, reliability, and limitation of these CT findings. The clinical material was consisted of 30 operatively proven cases of HNP of the lumbar spine. Each lumbar CT scan was reviewed retrospectively and the findings were analysed by two radiologists independently. There were 20 males and 10 females and the mean age was 36.7 years. Involvement of L4-S5 level was 2.3 times more frequent than that of L5-S1 level. Of 30 cases, 22 were unilateral posterolateral types and 8 cases central or unilateral far lateral types. CT findings observed were nodular protrusion of the posterior margin of the disc, obliteration of epidural fat pad, impingement of dural sac or nerve root, soft tissue density in the spinal canal and calcification in the posterior portion of the protruded disc, in order of decreasing frequency. The conclusions are follows: 1. Nodular protrusion of the posterior disc margin accompanied by obliteration of epidural fat pad was observed in every case. The former findings was designated as direct sign and the latter indirect. 2. Obliteration of the epidural fat appears to be significant in lateral recesses especially when it occurs unilaterally. This was not true, however, in the centrally located fat pad. 3. Impingement of the dural sac and nerve root were observed in 90% and 67%, respectively, and were very helpful in establishing HNP diagnosis when the direct and indirect signs were equivocal

The Galactic stellar disc

International Nuclear Information System (INIS)

Feltzing, S; Bensby, T

2008-01-01

The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular, we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained elemental abundances and ages based on high-resolution spectroscopy. For all the stars we also have full kinematic information as well as information about their stellar orbits. We confirm results from previous studies that the thin and the thick discs have distinct abundance patterns. But we also explore a larger range of orbital parameters than what has been possible in our previous studies. Several new results are presented. We find that stars that reach high above the Galactic plane and have eccentric orbits show remarkably tight abundance trends. This implies that these stars formed out of well-mixed gas that had been homogenized over large volumes. We find some evidence that suggest that the event that most likely caused the heating of this stellar population happened a few billion years ago. Through a simple, kinematic exploration of stars with super-solar [Fe/H], we show that the solar neighbourhood contains metal-rich, high velocity stars that are very likely associated with the thick disc. Additionally, the HR1614 moving group and the Hercules and Arcturus stellar streams are discussed and it is concluded that, probably, a large fraction of the groups and streams so far identified in the disc are the result of evolution and interactions within the stellar disc rather than being dissolved stellar clusters or engulfed dwarf galaxies.

Björk-Shiley strut fracture and disc escape: literature review and a method of disc retrieval.

Science.gov (United States)

Hendel, P N

1989-03-01

Embolization of a prosthetic valve poppet is a rare but life-threatening event. It was reported sporadically before the introduction of the Björk-Shiley 70-degree convexoconcave prosthesis in 1980. Since that time, there have been a large number of reported mechanical failures with disc escape. The rate for the 29-mm to 33-mm mitral valves is estimated as 5.2%. In 29 of 35 patients (including the 2 presented here) in whom the site of disc lodgment could be determined, the disc was in the descending or abdominal aorta. Fifteen of these patients died. Six survivors had the disc removed at the same operation and 6 at a later operation. In 2 patients, the disc was not removed. In 2 patients in whom the disc was not removed initially, it was thought to contribute to postoperative complications. Two more cases of structural failure of the Björk-Shiley convexoconcave prosthesis are presented. A transpericardial approach to the descending aorta on bypass is described. It allows easy removal of the disc and eliminates the need for a second operation.

Patellofemoral Joint Arthroplasty: Our Experience in Isolated Patellofemoral and Bicompartmental Arthritic Knees

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L. Sabatini

2016-01-01

Full Text Available Introduction Isolated patellofemoral (PF arthritis is rare, and there is no complete agreement about the best surgical treatment. The operative treatments are total knee arthroplasty and patellofemoral replacement (PFR. The incidence of many early complications of PF arthroplasty has decreased with the introduction of newer designs. Nowadays, the main cause of revision surgery is the progression of tibiofemoral osteoarthritis. In the past, PF arthroplasty was contraindicated in patients with evidence of osteoarthritis or pain in medial or lateral tibiofemoral compartments. The improvement in implant designs and surgical techniques has allowed the addition of a monocompartmental arthroplasty for the medial or lateral tibiofemoral compartment. In this work, we evaluate our first experience with PF arthroplasty and its combination with unicompartmental knee arthroplasty. Materials and Methods From May 2014 to March 2016, we treated 14 patients. An isolated PF arthroplasty was performed in six knees (five patients, and a combined PF and unicompartmental knee arthroplasty was performed in nine cases. We observed a significant improvement in the clinical and functional Knee Society Scores (KSSs after surgery in our patients. Results We obtained good results in our cases both for clinical and functional KSSs. Patellar clunk was recorded in one case. Discussion and Conclusion We are going toward a new attitude in which partial osteoarthritic changes could be treated with partial resurfacing prosthetic solutions such as unicompartmental, bi–unicompartmental or PFR alone, or unicompartmental combined, which respects the cruciates and achieves maximal bone preservation, which is vital, particularly, for young patients.

Experience of the posterior lip augmentation device in a regional hip arthroplasty unit as a treatment for recurrent dislocation.

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Hoggett, L; Cross, C; Helm, T

2017-12-01

Dislocation after total hip arthroplasty (THA) remains a significant complication of the procedure and is the third leading cause for revision THA. One technique for treatment of this complication is the use of the posterior lip augmentation device (PLAD). We describe our experience using the PLAD including complication rates. A retrospective review of 55 PLADs (54 patients) was carried out following identification from electronic theatre records. Basic patient demographics, operative records and radiographs were collected and reviewed and data was analysed using Microsoft Excel. Failure of the PLAD was defined as further operative intervention after PLAD insertion and included: dislocation, implant breakage, infection and revision of the THA for loosening of either component. 55 PLADs were implanted in 54 patients with an average age of 77 years. There was a significant preponderance of females and a variety of surgical approaches had been used for the original hip replacement, including trochanteric osteotomy, posterior and antero-lateral. 9 (16%) patients had recurrent dislocations,1 (2%) failed secondary to screw breakage, 3 (5%) had and infection requiring intervention and 2 (4%) underwent further revision for aseptic loosening of the femoral component. The overall failure rate was 25% with 14 patients requiring intervention post PLAD. Our results are inferior to other published results and indicate that the PLAD should be used with caution for recurrent dislocations of the Charnley hip replacement.

Infected primary knee arthroplasty: Risk factors for surgical treatment failure

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Joao Gabriel Duarte Paes Pradella

2013-09-01

Full Text Available OBJECTIVE: To present epidemiological data and risk factors associated with surgical out-comes favorable or unfavorable for the treatment of infection in infected total knee arthroplasty. METHODS: We reviewed medical records of 48 patients who underwent treatment of primary total knee arthroplasty for infection between January 1994 and December 2008, in the Orthopedics and Traumatology Department of the Santa Casa de Misericórdia de São Paulo. The variables associated with favorable outcome of surgical treatment (debridement and retention or exchange arthroplasty in two days or unfavorable (arthrodesis or death infection. RESULTS: A total of 39 cases of infection after primary total knee arthroplasty, 22 progressed to 17 for a favorable outcome and unfavorable outcome. Early infections (OR: 14.0, 95% CI 1.5-133.2, p = 0.016 and diabetes (OR: 11.3, 95% CI 1.4-89.3, p = 0.032 were associated with arthrodesis joint and death respectively. CONCLUSION: Patients with early infection had a higher risk of developing surgical procedure with unfavorable outcome (arthrodesis and diabetics had higher odds of death after infection of primary knee arthroplasties.

Debris disc constraints on planetesimal formation

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Krivov, Alexander V.; Ide, Aljoscha; Löhne, Torsten; Johansen, Anders; Blum, Jürgen

2018-02-01

Two basic routes for planetesimal formation have been proposed over the last decades. One is a classical `slow-growth' scenario. Another one is particle concentration models, in which small pebbles are concentrated locally and then collapse gravitationally to form planetesimals. Both types of models make certain predictions for the size spectrum and internal structure of newly born planetesimals. We use these predictions as input to simulate collisional evolution of debris discs left after the gas dispersal. The debris disc emission as a function of a system's age computed in these simulations is compared with several Spitzer and Herschel debris disc surveys around A-type stars. We confirm that the observed brightness evolution for the majority of discs can be reproduced by classical models. Further, we find that it is equally consistent with the size distribution of planetesimals predicted by particle concentration models - provided the objects are loosely bound `pebble piles' as these models also predict. Regardless of the assumed planetesimal formation mechanism, explaining the brightest debris discs in the samples uncovers a `disc mass problem'. To reproduce such discs by collisional simulations, a total mass of planetesimals of up to ˜1000 Earth masses is required, which exceeds the total mass of solids available in the protoplanetary progenitors of debris discs. This may indicate that stirring was delayed in some of the bright discs, that giant impacts occurred recently in some of them, that some systems may be younger than previously thought or that non-collisional processes contribute significantly to the dust production.

Sports Activity Following Cementless Metaphyseal Hip Joint Arthroplasty

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Czech Szymon

2017-12-01

Full Text Available An adequate level of physical activity has a substantial effect on both mental and physical human health. Physical activity is largely dependent on the function of the musculoskeletal and articular system. One of the most frequent diseases of this system is degenerative joint disease. Due to the changing and more demanding lifestyles and patients’ willingness to be involved in sports activity, the expectations of hip joint arthroplasty are becoming increasingly high. Alleviating pain ceases to be the only reason for which patients choose surgical interventions, while the expectations often include involvement in various sports. Only few studies contain recommendations concerning the frequency, type and intensity of sports activity which are acceptable after hip joint arthroplasty. The aim of the study was to evaluate function and physical activity of people following cementless short-stem hip joint arthroplasty in the observation of at least five years. The study group comprised 106 patients who underwent total hip arthroplasty due to degenerative joint diseases, chosen according to inclusion criteria. Patients underwent routine physical examinations following the Harris Hip Score protocol, responded to the UCLA scale and questionnaires concerning pre-surgical and current physical activity. Our results demonstrated that hip joint arthroplasty in people suffering from degenerative joint diseases has a beneficial effect on their level of functioning and physical activity. Although physical activity and the level of functioning obviously reduced as a person aged, the level of physical activity continued to be very high in both groups, with function of the hip joint evaluated as very good.

Sports Activity Following Cementless Metaphyseal Hip Joint Arthroplasty.

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Czech, Szymon; Hermanson, Jacek; Rodak, Piotr; Stołtny, Tomasz; Rodak, Łukasz; Kasperczyk, Sławomir; Koczy, Bogdan; Mielnik, Michał

2017-12-01

An adequate level of physical activity has a substantial effect on both mental and physical human health. Physical activity is largely dependent on the function of the musculoskeletal and articular system. One of the most frequent diseases of this system is degenerative joint disease. Due to the changing and more demanding lifestyles and patients' willingness to be involved in sports activity, the expectations of hip joint arthroplasty are becoming increasingly high. Alleviating pain ceases to be the only reason for which patients choose surgical interventions, while the expectations often include involvement in various sports. Only few studies contain recommendations concerning the frequency, type and intensity of sports activity which are acceptable after hip joint arthroplasty. The aim of the study was to evaluate function and physical activity of people following cementless short-stem hip joint arthroplasty in the observation of at least five years. The study group comprised 106 patients who underwent total hip arthroplasty due to degenerative joint diseases, chosen according to inclusion criteria. Patients underwent routine physical examinations following the Harris Hip Score protocol, responded to the UCLA scale and questionnaires concerning pre-surgical and current physical activity. Our results demonstrated that hip joint arthroplasty in people suffering from degenerative joint diseases has a beneficial effect on their level of functioning and physical activity. Although physical activity and the level of functioning obviously reduced as a person aged, the level of physical activity continued to be very high in both groups, with function of the hip joint evaluated as very good.

T1 hyperintense disc in alkaptonuria.

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Sag, Alan A; Silbergleit, Richard; Olson, Rick E; Wilson, Jon; Krishnan, Anant

2012-10-01

Case report. To report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation. A 46-year-old man without previous diagnosis of alkaptonuria underwent evaluation for progressive back pain revealing a T1-hyperintense disc herniation at the L3-L4 level. Discectomy recovered a blackened disc that was pathologically confirmed to be nucleus pulposus with alkaptonuric involvement. The differential diagnosis of a T1-hyperintense, T2-hypointense disc on magnetic resonance imaging is discussed, with emphasis on the pathophysiology of alkaptonuria. A single patient is reported. Pathologically proven patient presentation with radiological and pathological images. We report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation.

Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

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van Raaij Jos JAM

2008-10-01

Full Text Available Abstract Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA, serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score, physician reported functional status and range of motion (Harris hip score, number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years. Discussion

Displays mounted on cutting blocks reduce the learning curve in navigated total knee arthroplasty.

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Schnurr, Christoph; Eysel, Peer; König, Dietmar Pierre

2011-01-01

The use of computer navigation in total knee arthroplasty (TKA) improves the implant alignment but increases the operation time. Studies have shown that the operation time is further prolonged due to the surgeon's learning curve, and longer operation times have been associated with higher morbidity risks. It has been our hypothesis that an improvement in the human-machine interface might reduce the time required during the learning curve. Accordingly, we asked whether the use of navigation devices with a display fixed on the surgical instruments would reduce the operation time in navigated TKAs performed by navigation beginners. Thirty medical students were randomized and used two navigation devices in rotation: these were the Kolibri® device with an external display and the Dash® device with a display that was fixed on the cutting blocks. The time for adjustment of the tibial and femoral cutting blocks on knee models while using these devices was measured. A significant time reduction was demonstration when the Dash® device was used: The time reduction was 21% for the tibial block (p = 0.007), 40% for the femoral block (p learning curve may be diminished.

Non-axisymmetric line-driven disc winds - I. Disc perturbations

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Dyda, Sergei; Proga, Daniel

2018-04-01

We study mass outflows driven from accretion discs by radiation pressure due to spectral lines. To investigate non-axisymmetric effects, we use the ATHENA++ code and develop a new module to account for radiation pressure driving. In 2D, our new simulations are consistent with previous 2D axisymmetric solutions by Proga et al., who used the ZEUS 2D code. Specifically, we find that the disc winds are time dependent, characterized by a dense stream confined to ˜45° relative to the disc mid-plane and bounded on the polar side by a less dense, fast stream. In 3D, we introduce a vertical, ϕ-dependent, subsonic velocity perturbation in the disc mid-plane. The perturbation does not change the overall character of the solution but global outflow properties such as the mass, momentum, and kinetic energy fluxes are altered by up to 100 per cent. Non-axisymmetric density structures develop and persist mainly at the base of the wind. They are relatively small, and their densities can be a few times higher than the azimuthal average. The structure of the non-axisymmetric and axisymmetric solutions differ also in other ways. Perhaps most importantly from the observational point of view are the differences in the so-called clumping factors, that serve as a proxy for emissivity due to two body processes. In particular, the spatially averaged clumping factor over the entire fast stream, while it is of a comparable value in both solutions, it varies about 10 times faster in the non-axisymmetric case.

The presence and absence of lymphatic vessels in the adult human intervertebral disc: relation to disc pathology

International Nuclear Information System (INIS)

Kliskey, Karolina; Williams, Kelly; Yu, J.; Urban, Jill; Athanasou, Nick; Jackson, David

2009-01-01

Although the normal adult human intervertebral disc is considered to be avascular, vascularised cellular fibrous tissue can be found in pathological conditions involving the disc such as disc herniation. Whether lymphatics vessels form a component of this reparative tissue is not known as the presence or absence of lymphatics in herniated and normal disc tissue is not known. We examined spinal tissues and discectomy specimens for the presence of lymphatics. The examination used immunohistochemistry to identify the specific lymphatic endothelial cell markers, podoplanin and LYVE1. Lymphatic vessels were not found in the nucleus pulposus or annulus fibrosus of intact, non-herniated lumbar and thoracic discs but were present in the surrounding ligaments. Ingrowth of fibrous tissue was seen in 73% of herniated disc specimens of which 36% contained LYVE1+/podoplanin + lymphatic vessels. Lymphatic vessels were not seen in the sacrum and coccyx or biopsies of four sacrococcygeal chordomas, but they were noted in surrounding extra-osseous fat and fibrous tissue at the edge of the infiltrating tumour. Our findings indicate that lymphatic vessels are not present in the normal adult intervertebral disc but that, when there is extrusion of disc material into surrounding soft tissue, there is ingrowth of reparative fibrous tissue containing lymphatic vessels. Our findings also indicate that chordoma, a tumour of notochordal origin, spreads to regional lymph nodes via lymphatics in para-spinal soft tissues. (orig.)

The risk of venous thromboembolism with aspirin compared to anticoagulants after hip and knee arthroplasty.

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Chu, Janet N; Maselli, Judith; Auerbach, Andrew D; Fang, Margaret C

2017-07-01

Recent guidelines include aspirin as an option to prevent venous thromboembolism (VTE) in selected patients undergoing hip or knee replacement surgery. However, the efficacy of aspirin after arthroplasty has not been well-defined, particularly in more contemporary patient populations. We compared rates of post-operative VTE between patients who received aspirin-only versus anticoagulants after hip or knee arthroplasty, using data from a large US-based administrative database. We conducted a retrospective cohort study of 231,780 adults who underwent total knee arthroplasty and 110,621 who underwent total hip arthroplasty in 2009-2012 and who received pharmacologic VTE prophylaxis (aspirin or anticoagulant) within the first 7days after surgery. We compared the risk of post-operative VTE between patients receiving aspirin-only vs. anticoagulants, controlling for clinical and hospital characteristics using multivariable logistic regression with propensity score adjustment. Aspirin-only prophylaxis was administered to 7.5% of patients after knee arthroplasty and 8.0% after hip arthroplasty. Post-operative VTE was diagnosed in 2217 (0.96%) patients after knee arthroplasty and 454 (0.41%) after hip arthroplasty. Compared to anticoagulants, aspirin was not associated with a higher risk for post-operative VTE either after knee arthroplasty (adjusted odds ratio and 95% confidence interval [OR] 0.34 [0.24-0.48]) or hip arthroplasty (OR 0.82 [0.45-1.51]). Aspirin was uncommonly administered as the sole prophylactic agent after hip or knee arthroplasty in this study. However, patients who received aspirin-only had similar rates of post-operative VTE compared to patients who received anticoagulants. Further research should focus on distinguishing which patients benefit more from anticoagulants versus aspirin after arthroplasty. Copyright © 2017 Elsevier Ltd. All rights reserved.

Post-irradiation examinations and high-temperature tests on undoped large-grain UO{sub 2} discs

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Noirot, J., E-mail: jean.noirot@cea.fr [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Pontillon, Y. [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Yagnik, S. [EPRI, P.O. Box 10412, Palo Alto, CA 94303-0813 (United States); Turnbull, J.A. [Independent Consultant (United Kingdom)

2015-07-15

Within the Nuclear Fuel Industry Research (NFIR) programme, several fuel variants –in the form of thin circular discs – were irradiated in the Halden Boiling Water Reactor (HBWR) at burn-ups up to ∼100 GWd/t{sub HM}. The design of the fuel assembly was similar to that used in other HBWR programmes: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature differences within each fuel disc. One such variant was made of large-grain UO{sub 2} discs (3D grain size = ∼45 μm) which were subjected to three burn-ups: 42, 72 and 96 GWd/t{sub HM}. Detailed characterizations of some of these irradiated large-grain UO{sub 2} discs were performed in the CEA Cadarache LECA-STAR hot laboratory. The techniques used included electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS). Comparisons were then carried out with more standard grain size UO{sub 2} discs irradiated under the same conditions. Examination of the high burn-up large-grain UO{sub 2} discs revealed the limited formation of a high burn-up structure (HBS) when compared with the standard-grain UO{sub 2} discs at similar burn-up. High burn-up discs were submitted to temperature transients up to 1200 °C in the heating test device called Merarg at a relatively low temperature ramp rate (0.2 °C/s). In addition to the total gas release during these tests, the release peaks throughout the temperature ramp were monitored. Tests at 1600 °C were also conducted on the 42 GWd/t{sub HM} discs. The fuels were then characterized with the same microanalysis techniques as those used before the tests, to investigate the effects of these tests on the fuel’s microstructure and on the fission gas behaviour. This paper outlines the high resistance of this fuel to gas precipitation at high temperature and to HBS formation at high burn-up. It also shows the similarity of the positions, within the grains, where HBS forms

Does core mobility of lumbar total disc arthroplasty influence sagittal and frontal intervertebral displacement? Radiologic comparison with fixed-core prosthesis

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Delécrin, Joël; Allain, Jérôme; Beaurain, Jacques; Steib, Jean-Paul; Chataigner, Hervé; Aubourg, Lucie; Huppert, Jean; Ameil, Marc; Nguyen, Jean-Michel

2009-01-01

Background An artificial disc prosthesis is thought to restore segmental motion in the lumbar spine. However, it is reported that disc prosthesis can increase the intervertebral translation (VT). The concept of the mobile-core prosthesis is to mimic the kinematic effects of the migration of the natural nucleus and therefore core mobility should minimize the VT. This study explored the hypothesis that core translation should influence VT and that a mobile core prosthesis may facilitate physiological motion. Methods Vertebral translation (measured with a new method presented here), core translation, range of motion (ROM), and distribution of flexion-extension were measured on flexion-extension, neutral standing, and lateral bending films in 89 patients (63 mobile-core [M]; 33 fixed-core [F]). Results At L4-5 levels the VT with M was lower than with F and similar to the VT of untreated levels. At L5-S1 levels the VT with M was lower than with F but was significantly different compared to untreated levels. At M levels a strong correlation was found between VT and core translation; the VT decreases as the core translation increases. At F levels the VT increases as the ROM increases. No significant difference was found between the ROM of untreated levels and levels implanted with either M or F. Regarding the mobility distribution with M and F we observed a deficit in extension at L5-S1 levels and a similar distribution at L4-5 levels compared to untreated levels. Conclusion The intervertebral mobility was different between M and F. The M at L4-5 levels succeeded to replicate mobility similar to L4-5 untreated levels. The M at L5-S1 succeeded in ROM, but failed regarding VT and mobility distribution. Nevertheless M minimized VT at L5-S1 levels. The F increased VT at both L4-5 and L5-S1. Clinical Relevance This study validates the concept that the core translation of an artificial lumbar disc prosthesis minimizes the VT. PMID:25802632

Shoulder arthroplasty in osteoarthritis: current concepts in biomechanics and surgical technique

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Merolla, G; Nastrucci, G; Porcellini, G

Shoulder arthroplasty is a technically demanding procedure to restore shoulder function in patients with severe osteoarthritis of the glenohumeral joint. The modern prosthetic system exploit the benefits of modularity and the availibility of additional sizes of the prosthetic components. In this paper we describe the biomechanics of shoulder arthroplasty and the technique for shoulder replacement including total shoulder arthroplasty (TSA) with all-polyethylene and metal-backed glenoid component, humeral head resurfacing and stemless humeral replacement. PMID:24251240

Return to sport after shoulder arthroplasty: a systematic review and meta-analysis.

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Liu, Joseph N; Steinhaus, Michael E; Garcia, Grant H; Chang, Brenda; Fields, Kara; Dines, David M; Warren, Russell F; Gulotta, Lawrence V

2018-01-01

With increasing incidence and indications for shoulder arthroplasty, there is an increasing emphasis on the ability to return to sports. The main goal of this study was to determine the rate of return to sport after shoulder arthroplasty. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to perform this systematic review and meta-analysis. A search was performed on MEDLINE, Scopus, EMBASE, and the Cochrane Library. The quality of the included studies was evaluated according to the Methodological Index for Nonrandomized Studies checklist. The main judgement outcome was the rate of return to sports activity after shoulder arthroplasty and the level of play upon return (identical or higher/lower level). Thirteen studies were reviewed, including 944 patients (506 athletes), treated with shoulder arthroplasty at an average follow-up of 5.1 years (range, 0.5-12.6 years). The most common sports were swimming (n = 169), golf (n = 144), fitness sports (n = 71), and tennis (n = 63). The overall rate of return to sport was 85.1% (95% CI, 76.5-92.3%), including 72.3% (95% CI, 60.6-82.8%) returning to an equivalent or improved level of play, after 1-36 months. Patients undergoing anatomic total shoulder arthroplasty returned at a significantly higher rate (92.6%) compared to hemiarthroplasty (71.1%, p = 0.02) or reverse total shoulder arthroplasty (74.9%, p = 0.003). Most patients are able to return to one or more sports following shoulder arthroplasty, with anatomic total shoulder arthroplasty having the highest rate of return. IV.

Archival-grade optical disc design and international standards

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Fujii, Toru; Kojyo, Shinichi; Endo, Akihisa; Kodaira, Takuo; Mori, Fumi; Shimizu, Atsuo

2015-09-01

Optical discs currently on the market exhibit large variations in life span among discs, making them unsuitable for certain business applications. To assess and potentially mitigate this problem, we performed accelerated degradation testing under standard ISO conditions, determined the probable disc failure mechanisms, and identified the essential criteria necessary for a stable disc composition. With these criteria as necessary conditions, we analyzed the physical and chemical changes that occur in the disc components, on the basis of which we determined technological measures to reduce these degradation processes. By applying these measures to disc fabrication, we were able to develop highly stable optical discs.

Activity and Quality of Life after Total Hip Arthroplasty.

Science.gov (United States)

Świtoń, Anna; Wodka-Natkaniec, Ewa; Niedźwiedzki, Łukasz; Gaździk, Tadeusz; Niedźwiedzki, Tadeusz

2017-10-31

Coxarthrosis is a chronic musculoskeletal condition that causes severe pain and considerable limi-tation of the patient's motor performance. Total hip arthroplasty is one of the most common and effective methods used in the treatment of advanced degenerative changes. The aim of the present study was to evaluate the activity and quality of life of patients after unilateral total hip arthroplasty. The study was conducted in a group of 189 patients who had undergone unilateral total hip arthroplasty. Goniometry was used to determine the range of motion of both hip joints. Patients' physical ability and pain severity were assessed based on the Harris Hip Score (HHS) questionnaire. The examination of the range of motion in the lower extremities revealed statistically significant diffe-rences in flexion (p<0.01), abduction (p=<0.01), adduction (p<0.01) and external rotation (p<0.01) between the operated and the healthy extremity. The greatest limitation of motion was demonstrated for external rotation (<14°). Approximately 14% of the patients were not able to perform this motion in their healthy hip joint, while 17.5% of them could not do so in the affected hip joint. Analysis of HHS results (mean = 79 pts) revealed that more than 50% of the patients described their functional ability and quality of life as good and excellent. It was demonstrated that 54% of patients did not suffer from pain, whereas minor or mild pain was noted in 35%. 1. A subjective clinical assessment of patients after total hip arthroplasty showed that their quality of life had improved. 2. It is necessary to perform physiotherapy after total hip arthroplasty, on both the operated and healthy side. 3. Exacerbation of pain and impaired activity in patients after total hip arthroplasty were associated with the female sex to a considerable extent.

Perioperative blood saving measures in total hip and knee arthroplasty

NARCIS (Netherlands)

Horstmann, W.G.

2011-01-01

This dissertation explores and discusses different aspects of blood loss and blood-saving measures in total hip and knee arthroplasty. Background: Worldwide, approximately 1 million total hip and 1 million total knee prostheses are implanted each year. Total hip arthroplasty and total

Short Operative Duration and Surgical Site Infection Risk in Hip and Knee Arthroplasty Procedures.

Science.gov (United States)

Dicks, Kristen V; Baker, Arthur W; Durkin, Michael J; Anderson, Deverick J; Moehring, Rebekah W; Chen, Luke F; Sexton, Daniel J; Weber, David J; Lewis, Sarah S

2015-12-01

To determine the association (1) between shorter operative duration and surgical site infection (SSI) and (2) between surgeon median operative duration and SSI risk among first-time hip and knee arthroplasties. Retrospective cohort study A total of 43 community hospitals located in the southeastern United States. Adults who developed SSIs according to National Healthcare Safety Network criteria within 365 days of first-time knee or hip arthroplasties performed between January 1, 2008 and December 31, 2012. Log-binomial regression models estimated the association (1) between operative duration and SSI outcome and (2) between surgeon median operative duration and SSI outcome. Hip and knee arthroplasties were evaluated in separate models. Each model was adjusted for American Society of Anesthesiology score and patient age. A total of 25,531 hip arthroplasties and 42,187 knee arthroplasties were included in the study. The risk of SSI in knee arthroplasties with an operative duration shorter than the 25th percentile was 0.40 times the risk of SSI in knee arthroplasties with an operative duration between the 25th and 75th percentile (risk ratio [RR], 0.40; 95% confidence interval [CI], 0.38-0.56; Poperative duration did not demonstrate significant association with SSI for hip arthroplasties (RR, 1.04; 95% CI, 0.79-1.37; P=.36). Knee arthroplasty surgeons with shorter median operative durations had a lower risk of SSI than surgeons with typical median operative durations (RR, 0.52; 95% CI, 0.43-0.64; Poperative durations were not associated with a higher SSI risk for knee or hip arthroplasty procedures in our analysis.

Elbow arthroplasty in perspective

NARCIS (Netherlands)

Heijink, A.

2017-01-01

This thesis focuses on the effect of biomechanical aspects of prosthesis design and outcome after radial head and total elbow arthroplasty. First, we examine the available evidence regarding the role of several unfavorable biomechanical conditions about the elbow in the development of

Cemented versus Uncemented Oxford Unicompartmental Knee Arthroplasty: Is There a Difference?

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Burak Akan

2013-01-01

Full Text Available Purpose. The use of uncemented unicompartmental knee prostheses has recently increased. However, few studies on the outcomes of uncemented unicompartmental knee prostheses have been performed. The purpose of this study was to compare the outcomes of cemented and uncemented Oxford unicompartmental knee arthroplasty. Materials and Methods. This retrospective observational study evaluated the clinical and radiological outcomes of 263 medial Oxford unicompartmental prostheses (141 cemented, 122 uncemented implanted in 235 patients. The mean follow-up was 42 months in the cemented group and 30 months in the uncemented group. Results. At the last follow-up, there were no significant differences in the clinical results or survival rates between the two groups. However, the operation time in the uncemented unicompartmental knee arthroplasty group was shorter than that in the cemented unicompartmental knee arthroplasty group. In addition, the cost of uncemented arthroplasty was greater. Conclusion. Despite the successful midterm results in the uncemented unicompartmental knee arthroplasty group, a longer follow-up period is required to determine the best fixation mode.

Thermochemical modelling of brown dwarf discs

NARCIS (Netherlands)

Greenwood, A. J.; Kamp, I.; Waters, L. B. F. M.; Woitke, P.; Thi, W.-F.; Rab, Ch.; Aresu, G.; Spaans, M.

The physical properties of brown dwarf discs, in terms of their shapes and sizes, are still largely unexplored by observations. ALMA has by far the best capabilities to observe these discs in sub-mm CO lines and dust continuum, while also spatially resolving some discs. To what extent brown dwarf

Patient expectations predict greater pain relief with joint arthroplasty.

Science.gov (United States)

Gandhi, Rajiv; Davey, John Roderick; Mahomed, Nizar

2009-08-01

We examined the relationship between patient expectations of total joint arthroplasty and functional outcomes. We surveyed 1799 patients undergoing primary hip or knee arthroplasty for demographic data and Western Ontario McMaster University Osteoarthritis Index scores at baseline, 3 months, and 1 year of follow-up. Patient expectations were determined with 3 survey questions. The patients with the greatest expectations of surgery were younger, male, and had a lower body mass index. Linear regression modeling showed that a greater expectation of pain relief with surgery independently predicted greater reported pain relief at 1 year of follow-up, adjusted for all relevant covariates (P relief after joint arthroplasty is an important predictor of outcomes at 1 year.

Combined in-depth, 3D, en face imaging of the optic disc, optic disc pits and optic disc pit maculopathy using swept-source megahertz OCT at 1050 nm.

Science.gov (United States)

Maertz, Josef; Kolb, Jan Philip; Klein, Thomas; Mohler, Kathrin J; Eibl, Matthias; Wieser, Wolfgang; Huber, Robert; Priglinger, Siegfried; Wolf, Armin

2018-02-01

To demonstrate papillary imaging of eyes with optic disc pits (ODP) or optic disc pit associated maculopathy (ODP-M) with ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s. To generate 3D-renderings of the papillary area with 3D volume-reconstructions of the ODP and highly resolved en face images from a single densely-sampled megahertz-OCT (MHz-OCT) dataset for investigation of ODP-characteristics. A 1.68 MHz-prototype SS-MHz-OCT system at 1050 nm based on a Fourier-domain mode-locked laser was employed to acquire high-definition, 3D datasets with a dense sampling of 1600 × 1600 A-scans over a 45° field of view. Six eyes with ODPs, and two further eyes with glaucomatous alteration or without ocular pathology are presented. 3D-rendering of the deep papillary structures, virtual 3D-reconstructions of the ODPs and depth resolved isotropic en face images were generated using semiautomatic segmentation. 3D-rendering and en face imaging of the optic disc, ODPs and ODP associated pathologies showed a broad spectrum regarding ODP characteristics. Between individuals the shape of the ODP and the appending pathologies varied considerably. MHz-OCT en face imaging generates distinct top-view images of ODPs and ODP-M. MHz-OCT generates high resolution images of retinal pathologies associated with ODP-M and allows visualizing ODPs with depths of up to 2.7 mm. Different patterns of ODPs can be visualized in patients for the first time using 3D-reconstructions and co-registered high-definition en face images extracted from a single densely sampled 1050 nm megahertz-OCT (MHz-OCT) dataset. As the immediate vicinity to the SAS and the site of intrapapillary proliferation is located at the bottom of the ODP it is crucial to image the complete structure and the whole depth of ODPs. Especially in very deep pits, where non-swept-source OCT fails to reach the bottom, conventional swept-source devices and the MHz-OCT alike are feasible

Bilateral simultaneous total hip arthroplasty in a fast track setting

DEFF Research Database (Denmark)

Otte, Kristian S; Husted, Henrik; Ørsnes, Thue

2011-01-01

and low complication rates when performed in a fast-track setting. We believed it would be useful to assess hip arthroplasty in this context, and we report 50 consecutive fast-track simultaneous bilateral hip arthroplasty procedures. The median length of stay was 4 days. Mortality within 90 days was 4......% and 8% required a further operative procedure. The overall complication rate was 22%. 55% of the complications were considered to be caused by failures in surgical technique and 45% by other factors. Bilateral simultaneous hip arthroplasty may have a high complication rate in a fast-track setting...

{100} or 45.degree.-rotated {100}, semiconductor-based, large-area, flexible, electronic devices

Science.gov (United States)

Goyal, Amit [Knoxville, TN

2012-05-15

Novel articles and methods to fabricate the same resulting in flexible, {100} or 45.degree.-rotated {100} oriented, semiconductor-based, electronic devices are disclosed. Potential applications of resulting articles are in areas of photovoltaic devices, flat-panel displays, thermophotovoltaic devices, ferroelectric devices, light emitting diode devices, computer hard disc drive devices, magnetoresistance based devices, photoluminescence based devices, non-volatile memory devices, dielectric devices, thermoelectric devices and quantum dot laser devices.

Notochord Cells in Intervertebral Disc Development and Degeneration

Science.gov (United States)

McCann, Matthew R.; Séguin, Cheryle A.

2016-01-01

The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches. PMID:27252900

Notochord Cells in Intervertebral Disc Development and Degeneration

Directory of Open Access Journals (Sweden)

Matthew R. McCann

2016-01-01

Full Text Available The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches.

The life cycles of Be viscous decretion discs: fundamental disc parameters of 54 SMC Be stars

Science.gov (United States)

Rímulo, L. R.; Carciofi, A. C.; Vieira, R. G.; Rivinius, Th; Faes, D. M.; Figueiredo, A. L.; Bjorkman, J. E.; Georgy, C.; Ghoreyshi, M. R.; Soszyński, I.

2018-05-01

Be stars are main-sequence massive stars with emission features in their spectrum, which originates in circumstellar gaseous discs. Even though the viscous decretion disc model can satisfactorily explain most observations, two important physical ingredients, namely the magnitude of the viscosity (α) and the disc mass injection rate, remain poorly constrained. The light curves of Be stars that undergo events of disc formation and dissipation offer an opportunity to constrain these quantities. A pipeline was developed to model these events that use a grid of synthetic light curves, computed from coupled hydrodynamic and radiative transfer calculations. A sample of 54 Be stars from the OGLE survey of the Small Magellanic Cloud (SMC) was selected for this study. Because of the way our sample was selected (bright stars with clear disc events), it likely represents the densest discs in the SMC. Like their siblings in the Galaxy, the mass of the disc in the SMC increases with the stellar mass. The typical mass and angular momentum loss rates associated with the disc events are of the order of ˜10-10 M⊙ yr-1 and ˜5 × 1036 g cm2 s-2, respectively. The values of α found in this work are typically of a few tenths, consistent with recent results in the literature and with the ones found in dwarf novae, but larger than current theory predicts. Considering the sample as a whole, the viscosity parameter is roughly two times larger at build-up ( = 0.63) than at dissipation ( = 0.26). Further work is necessary to verify whether this trend is real or a result of some of the model assumptions.

Transfusion practice in hip arthroplasty - a nationwide study

DEFF Research Database (Denmark)

Jans, Øivind; Kehlet, H; Hussain, Zubair Butt

2011-01-01

) in Denmark. Materials and Methods We performed a retrospective cohort study of all patients undergoing THA or RTHA in Denmark in 2008. Primary outcomes were intercentre variation in red blood cell (RBC) transfusion rates and the timing of transfusion related to surgery. Results Six thousand nine hundred......Background and Objectives The optimal transfusion strategy in hip arthroplasty remains controversial despite existing guidelines. The aim of this study was to evaluate the transfusion practice in patients undergoing primary total hip arthroplasty (THA) or revision total hip arthroplasty (RTHA...... thirty-two THA patients and 1132 RTHA patients were included for analysis of which 1674 (24%) THA and 689 (61%) RTHA patients received RBC transfusion. Of these, 47% of THA and 73% of RTHA patients received transfusion on the day of surgery. Transfusion rates between centres varied from 7 to 71...

High-performance spinning device for DVD-based micromechanical signal transduction

DEFF Research Database (Denmark)

Hwu, En-Te; Chen, Ching-Hsiu; Bosco, Filippo

2013-01-01

Here we report a high-throughput spinning device for nanometric scale measurements of microstructures with instrumentation details and experimental results. The readout technology implemented in the designed disc-like device is based on a DVD data storage optical pick-up unit (OPU). With a spinning...

Care principles at four fast-track arthroplasty departments in Denmark

DEFF Research Database (Denmark)

Husted, Henrik; Solgaard, Søren; Hansen, Torben B

2010-01-01

The goal of this study was to describe the logistic and clinical set-up at four Danish arthroplasty departments offering fast-track surgery.......The goal of this study was to describe the logistic and clinical set-up at four Danish arthroplasty departments offering fast-track surgery....

Low implant migration of the SIGMA® medial unicompartmental knee arthroplasty

DEFF Research Database (Denmark)

Koppens, Daan; Stilling, Maiken; Munk, Stig

2017-01-01

The purpose of this study was to evaluate implant migration of the fixed-bearing Sigma® medial unicompartmental knee arthroplasty (UKA). UKA is a regularly used treatment for patients with medial osteoarthritis (OA) of the knee. UKA has a higher revision rate than total knee arthroplasty. Implant...

Changes in collagen metabolites in serum after cemented hip and knee arthroplasty

DEFF Research Database (Denmark)

Joerring, S; Jensen, L T

1993-01-01

Markers of types I and III collagen turnover were measured in serial blood samples collected preoperatively and 60 days after surgery in 13 patients undergoing cemented total hip arthroplasty and 11 patients undergoing cemented total knee arthroplasty. The markers were the carboxyterminal extension....... We suggest that the changes in serum PICP and serum PIIINP reflect collagen formation in healing soft connective tissue 60 days after cemented hip or knee arthroplasty....

On the illumination of neutron star accretion discs

Science.gov (United States)

Wilkins, D. R.

2018-03-01

The illumination of the accretion disc in a neutron star X-ray binary by X-rays emitted from (or close to) the neutron star surface is explored through general relativistic ray tracing simulations. The applicability of the canonical suite of relativistically broadened emission line models (developed for black holes) to discs around neutron stars is evaluated. These models were found to describe well emission lines from neutron star accretion discs unless the neutron star radius is larger than the innermost stable orbit of the accretion disc at 6 rg or the disc is viewed at high inclination, above 60° where shadowing of the back side of the disc becomes important. Theoretical emissivity profiles were computed for accretion discs illuminated by hotspots on the neutron star surfaces, bands of emission and emission by the entirety of the hot, spherical star surface and in all cases, the emissivity profile of the accretion disc was found to be well represented by a single power law falling off slightly steeper than r-3. Steepening of the emissivity index was found where the emission is close to the disc plane and the disc can appear truncated when illuminated by a hotspot at high latitude. The emissivity profile of the accretion disc in Serpens X-1 was measured and found to be consistent with a single unbroken power law with index q=3.5_{-0.4}^{+0.3}, suggestive of illumination by the boundary layer between the disc and neutron star surface.

Minimum weight design of inhomogeneous rotating discs

International Nuclear Information System (INIS)

Jahed, Hamid; Farshi, Behrooz; Bidabadi, Jalal

2005-01-01

There are numerous applications for gas turbine discs in the aerospace industry such as in turbojet engines. These discs normally work under high temperatures while subjected to high angular velocities. Minimizing the weight of such items in aerospace applications results in benefits such as low dead weights and lower costs. High speed of rotation causes large centrifugal forces in a disc and simultaneous application of high temperatures reduces disc material strength. Thus, the latter effects tend to increase deformations of the disc under the applied loads. In order to obtain a reliable disc analysis and arrive at the corresponding correct stress distribution, solutions should consider changes in material properties due to the temperature field throughout the disc. To achieve this goal, an inhomogeneous disc model with variable thickness is considered. Using the variable material properties method, stresses are obtained for the disc under rotation and a steady temperature field. In this paper this is done by modelling the rotating disc as a series of rings of different but constant properties. The optimum disc profile is arrived at by sequentially proportioning the thicknesses of each ring to satisfy the stress requirements. This method vis-a-vis a mathematical programming procedure for optimization shows several advantages. Firstly, it is simple iterative proportioning in each design cycle not requiring involved mathematical operations. Secondly, due to its simplicity it alleviates the necessity of certain simplifications that are common in so-called rigorous mathematical procedures. The results obtained, compared to those published in the literature show agreement and superiority. A further advantage of the proposed method is the independence of the end results from the initially assumed point in the iterative design routine, unlike most methods published so far

Spectroscopic Parameters of Lumbar Intervertebral Disc Material

Science.gov (United States)

Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.

2009-06-01

There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

Revision of infected knee arthroplasties in Denmark

DEFF Research Database (Denmark)

Lindberg-Larsen, Martin; Jørgensen, Christoffer C; Bagger, Jens

2016-01-01

Background and purpose - The surgical treatment of periprosthetic knee infection is generally either a partial revision procedure (open debridement and exchange of the tibial insert) or a 2-stage exchange arthroplasty procedure. We describe the failure rates of these procedures on a nationwide...... basis. Patients and methods - 105 partial revisions (100 patients) and 215 potential 2-stage revision procedures (205 patients) performed due to infection from July 1, 2011 to June 30, 2013 were identified from the Danish Knee Arthroplasty Register (DKR). Failure was defined as surgically related death...

Postoperative radiologic imaging of joint arthroplasty; Postoperative radiologische Beurteilung von Gelenkendoprothesen

Energy Technology Data Exchange (ETDEWEB)

Aldinger, P.R. [Abt. Orthopaedie I, Orthopaedische Universitaetsklinik Heidelberg (Germany); Ludwig, K. [Sektion Diagnostische Radiologie, Orthopaedische Universitaetsklinik Heidelberg (Germany)

2006-06-15

With increased life expectancy in industrialised countries, improvement of implant design and operative technique, arthroplasty has become a routine procedure. The hip and knee joints are treated by arthroplasty most frequently. Nowadays joint replacement can be performed in many other joints. Radiologic imaging is an important tool for evaluation of the operative results and for detection of early and late complications. In the following article we describe the relevance of different imaging modalities as well as their systematic application in patients with joint arthroplasty. (orig.)

Biomaterials for intervertebral disc regeneration and repair.

Science.gov (United States)

Bowles, Robert D; Setton, Lori A

2017-06-01

The intervertebral disc contributes to motion, weight bearing, and flexibility of the spine, but is susceptible to damage and morphological changes that contribute to pathology with age and injury. Engineering strategies that rely upon synthetic materials or composite implants that do not interface with the biological components of the disc have not met with widespread use or desirable outcomes in the treatment of intervertebral disc pathology. Here we review bioengineering advances to treat disc disorders, using cell-supplemented materials, or acellular, biologically based materials, that provide opportunity for cell-material interactions and remodeling in the treatment of intervertebral disc disorders. While a field still in early development, bioengineering-based strategies employing novel biomaterials are emerging as promising alternatives for clinical treatment of intervertebral disc disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

On the diversity and statistical properties of protostellar discs

Science.gov (United States)

Bate, Matthew R.

2018-04-01

We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈105 yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales ≲ 104 yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r-1. Disc to protostar mass ratios rarely exceed two, with a typical range of Md/M* = 0.1-1 to ages ≲ 104 yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.

Effect of body mass index on functional outcomes following arthroplasty procedures.

Science.gov (United States)

Polat, Gokhan; Ceylan, Hasan Huseyin; Sayar, Safak; Kucukdurmaz, Fatih; Erdil, Mehmet; Tuncay, Ibrahim

2015-12-18

To evaluate the body mass index (BMI) change in arthroplasty patients and its impact on the patients' functional results. Between October 2010 and May 2013, 606 patients who were operated due to gonarthrosis, coxarthrosis, aseptic loosening of the total knee and hip prosthesis were evaluated prospectively. Patients were operated by three surgeons in three medical centers. Patients who were between 30-90 years of age and who were underwent total knee arthroplasty, total hip arthroplasty, revision knee arthroplasty, or revision hip arthroplasty were included in the study. We excluded the patients who cannot tolerate our standard postoperative rehabilitation program. Additionally, patients who had systemic inflammatory diseases, diabetes mellitus, or endochrinopathies were excluded from the study. The remaining 513 patients comprised our study group. Preoperative functional joint scores, height, weight and BMI of all patients were recorded. We used the Knee Society Score (KSS) for knee and Harris Hip Score (HHS) for hip patients. Postoperative functional scores were measured at 1(st), 6(th) and 12(th) months and recorded separately at outpatient visits. The mean age of the patients was 64.7 (range: 30-90) years (207 males/306 females) and the mean follow-up duration was 14.3 (range: 12-26) mo. We found that arthroplasty patients had weight gain and had an increase in BMI at the postoperative 1(st), 6(th) and 12(th) months. The mean BMI of the patients was 27.7 preoperatively, 27.8 at the postoperative 1(st) month, 28.1 at the 6(th) month and 28.6 at the 12(th) month (P < 0.01). At the last visit, the mean postoperative HHS of the hip arthroplasty patients was 82.2 ± 7.12 (preoperatively, 52.3; 1(st) month, 78.2; 6(th) month, 81.1; 12(th) month, 82.2), and the mean KSS of the knee arthroplasty patients was 79.3 ± 4.31 (preoperatively, 35.8; 1(st) month, 75.2; 6(th) month, 79.1; 12(th) month, 79.3). Worse functional results were noted in the patients who had a BMI

Aspirin or Rivaroxaban for VTE Prophylaxis after Hip or Knee Arthroplasty.

Science.gov (United States)

Anderson, David R; Dunbar, Michael; Murnaghan, John; Kahn, Susan R; Gross, Peter; Forsythe, Michael; Pelet, Stephane; Fisher, William; Belzile, Etienne; Dolan, Sean; Crowther, Mark; Bohm, Eric; MacDonald, Steven J; Gofton, Wade; Kim, Paul; Zukor, David; Pleasance, Susan; Andreou, Pantelis; Doucette, Steve; Theriault, Chris; Abianui, Abongnwen; Carrier, Marc; Kovacs, Michael J; Rodger, Marc A; Coyle, Doug; Wells, Philip S; Vendittoli, Pascal-Andre

2018-02-22

Clinical trials and meta-analyses have suggested that aspirin may be effective for the prevention of venous thromboembolism (proximal deep-vein thrombosis or pulmonary embolism) after total hip or total knee arthroplasty, but comparisons with direct oral anticoagulants are lacking for prophylaxis beyond hospital discharge. We performed a multicenter, double-blind, randomized, controlled trial involving patients who were undergoing total hip or knee arthroplasty. All the patients received once-daily oral rivaroxaban (10 mg) until postoperative day 5 and then were randomly assigned to continue rivaroxaban or switch to aspirin (81 mg daily) for an additional 9 days after total knee arthroplasty or for 30 days after total hip arthroplasty. Patients were followed for 90 days for symptomatic venous thromboembolism (the primary effectiveness outcome) and bleeding complications, including major or clinically relevant nonmajor bleeding (the primary safety outcome). A total of 3424 patients (1804 undergoing total hip arthroplasty and 1620 undergoing total knee arthroplasty) were enrolled in the trial. Venous thromboembolism occurred in 11 of 1707 patients (0.64%) in the aspirin group and in 12 of 1717 patients (0.70%) in the rivaroxaban group (difference, 0.06 percentage points; 95% confidence interval [CI], -0.55 to 0.66; Paspirin group and in 5 (0.29%) in the rivaroxaban group (difference, 0.18 percentage points; 95% CI, -0.65 to 0.29; P=0.42). Clinically important bleeding occurred in 22 patients (1.29%) in the aspirin group and in 17 (0.99%) in the rivaroxaban group (difference, 0.30 percentage points; 95% CI, -1.07 to 0.47; P=0.43). Among patients who received 5 days of rivaroxaban prophylaxis after total hip or total knee arthroplasty, extended prophylaxis with aspirin was not significantly different from rivaroxaban in the prevention of symptomatic venous thromboembolism. (Funded by the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT01720108 .).

Queixas auditivas de disc jockeys da cidade de Recife Auditory complaints in disc jockeys in Recife

Directory of Open Access Journals (Sweden)

Eliza Maia de Britto Macedo

2011-06-01

Full Text Available OBJETIVO: investigar a ocorrência de queixas auditivas em disc jockeys da cidade de Recife/PE. MÉTODOS: foi realizada uma entrevista com 30 disc jockeys, com idade entre 19 e 28 anos, abordando informações ocupacionais, conhecimentos gerais sobre o ruído e queixas auditivas (diminuição da acuidade auditiva, desconforto a sons intensos, zumbido, sensação de ouvido abafado e otalgia. A análise foi realizada por meio de abordagem quantitativa, utilizando o teste estatístico t-student. RESULTADOS: dentre os dados mais relevantes, destacam-se: 46,7% dos disc jockeys apresentaram, espontaneamente, queixas auditivas, em especial, a diminuição da acuidade auditiva (relatada por todos os sujeitos; 14 disc jockeys (46,67% referiram desconforto a sons intensos e 13 (43,33% mencionaram zumbido. Todos afirmaram ter conhecimento sobre os riscos do ruído para a saúde auditiva, mas 76,7% não realizam qualquer medida preventiva de suas consequências. A perda auditiva foi referida pelos sujeitos como o principal risco da exposição a níveis intensos de pressão sonora. CONCLUSÃO: todos os disc jockeys apresentaram queixa de perda auditiva e, entre as demais queixas auditivas, destacaram-se o desconforto a sons intensos e o zumbido. Tendo em vista a irreversibilidade da perda auditiva induzida por elevados níveis de pressão sonora, os disc jockeys devem ser periodicamente avaliados a fim de que se confirme ou não a perda auditiva de que se queixaram e, caso ela exista, deve ser monitorada para que seja passível de intervenção pelo fonoaudiólogo. Desta forma, percebe-se a necessidade de atuação da Fonoaudiologia junto aos disc jockeys, uma vez que poder-se-á propiciar a otimização do exercício profissional com o mínimo de risco possível.PURPOSE: to investigate the occurrence of auditory complaints in disc jockeys from the city of Recife/PE. METHODS: an interview was carried through with 30 disc jockeys aged between 19 and 48 years

The reports of thick discs' deaths are greatly exaggerated. Thick discs are NOT artefacts caused by diffuse scattered light

Science.gov (United States)

Comerón, S.; Salo, H.; Knapen, J. H.

2018-02-01

Recent studies have made the community aware of the importance of accounting for scattered light when examining low-surface-brightness galaxy features such as thick discs. In our past studies of the thick discs of edge-on galaxies in the Spitzer Survey of Stellar Structure in Galaxies - the S4G - we modelled the point spread function as a Gaussian. In this paper we re-examine our results using a revised point spread function model that accounts for extended wings out to more than 2\\farcm5. We study the 3.6 μm images of 141 edge-on galaxies from the S4G and its early-type galaxy extension. Thus, we more than double the samples examined in our past studies. We decompose the surface-brightness profiles of the galaxies perpendicular to their mid-planes assuming that discs are made of two stellar discs in hydrostatic equilibrium. We decompose the axial surface-brightness profiles of galaxies to model the central mass concentration - described by a Sérsic function - and the disc - described by a broken exponential disc seen edge-on. Our improved treatment fully confirms the ubiquitous occurrence of thick discs. The main difference between our current fits and those presented in our previous papers is that now the scattered light from the thin disc dominates the surface brightness at levels below μ 26 mag arcsec-2. We stress that those extended thin disc tails are not physical, but pure scattered light. This change, however, does not drastically affect any of our previously presented results: 1) Thick discs are nearly ubiquitous. They are not an artefact caused by scattered light as has been suggested elsewhere. 2) Thick discs have masses comparable to those of thin discs in low-mass galaxies - with circular velocities vc< 120 km s-1 - whereas they are typically less massive than the thin discs in high-mass galaxies. 3) Thick discs and central mass concentrations seem to have formed at the same epoch from a common material reservoir. 4) Approximately 50% of the up

Intraoperative CT navigation for glenoid component fixation in reverse shoulder arthroplasty

Directory of Open Access Journals (Sweden)

Ashok S Gavaskar

2013-01-01

Full Text Available CT navigation has been shown to improve component positioning in total shoulder arthroplasty. The technique can be useful in achieving strong initial fixation of the metal backed glenoid in reverse shoulder arthroplasty. We report a 61 years male patient who underwent reverse shoulder arthroplasty for rotator cuff arthropathy. CT navigation was used intraoperatively to identify best possible glenoid bone and to maximize the depth of the fixation screws that anchor the metaglene portion of the metal backed glenoid component. Satisfactory positioning of screws and component was achieved without any perforation or iatrogenic fracture in the scapula. CT navigation can help in maximizing the purchase of the fixation screws that dictate the initial stability of the glenoid component in reverse shoulder arthroplasty. The technique can be extended to improve glenoid component position [version and tilt] with the availability of appropriate software.

The Correlation between Insertion Depth of Prodisc-C Artificial Disc and Postoperative Kyphotic Deformity: Clinical Importance of Insertion Depth of Artificial Disc.

Science.gov (United States)

Lee, Do-Youl; Kim, Se-Hoon; Suh, Jung-Keun; Cho, Tai-Hyoung; Chung, Yong-Gu

2012-09-01

This study was designed to investigate the correlation between insertion depth of artificial disc and postoperative kyphotic deformity after Prodisc-C total disc replacement surgery, and the range of artificial disc insertion depth which is effective in preventing postoperative whole cervical or segmental kyphotic deformity. A retrospective radiological analysis was performed in 50 patients who had undergone single level total disc replacement surgery. Records were reviewed to obtain demographic data. Preoperative and postoperative radiographs were assessed to determine C2-7 Cobb's angle and segmental angle and to investigate postoperative kyphotic deformity. A formula was introduced to calculate insertion depth of Prodisc-C artificial disc. Statistical analysis was performed to search the correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity, and to estimate insertion depth of Prodisc-C artificial disc to prevent postoperative kyphotic deformity. In this study no significant statistical correlation was observed between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity regarding C2-7 Cobb's angle. Statistical correlation between insertion depth of Prodisc-C artificial disc and postoperative kyphotic deformity was observed regarding segmental angle (p<0.05). It failed to estimate proper insertion depth of Prodisc-C artificial disc effective in preventing postoperative kyphotic deformity. Postoperative segmental kyphotic deformity is associated with insertion depth of Prodisc-C artificial disc. Anterior located artificial disc leads to lordotic segmental angle and posterior located artificial disc leads to kyphotic segmental angle postoperatively. But C2-7 Cobb's angle is not affected by artificial disc location after the surgery.

Comparison of hip function and quality of life of total hip arthroplasty and resurfacing arthroplasty in the treatment of young patients with arthritis of the hip joint at 5 years.

Science.gov (United States)

Costa, Matthew L; Achten, Juul; Foguet, Pedro; Parsons, Nicholas R

2018-03-12

To compare the medium-term clinical effectiveness of total hip arthroplasty and resurfacing arthroplasty. Single centre, two-arm, parallel group, assessor blinded, randomised controlled trial with 1:1 treatment allocation. A large teaching hospital in England. 122 patients older than 18 years with severe arthritis of the hip joint, suitable for resurfacing arthroplasty of the hip. Patients were excluded if they were considered to be unable to adhere to trial procedures or complete questionnaires. Total hip arthroplasty (replacement of entire femoral head and neck); hip resurfacing arthroplasty (replacement of the articular surface of femoral head only, femoral neck remains intact). Both procedures replaced the articular surface of the acetabulum. The outcome measures were hip function assessed using the Oxford Hip Score (OHS) and health-related quality of life assessed using the EuroQol (EQ-5D). Patients were followed up annually for a minimum of 5 years. Outcome data were modelled using the generalised estimating equation methodology to explore temporal variations during follow-up. 60 patients were randomly assigned to hip resurfacing arthroplasty and 62 to total hip arthroplasty. 95 (78%) of the 122 original study participants provided data at 5 years. There was a small decrease in both hip functions and quality of life in both groups of patients each year during the 5-year follow-up period. However, there was no evidence of a significant difference between treatments group in the OHS (P=0.333) or the EQ-5D (P=0.501). We previously reported no difference in outcome in the first year after surgery. The current medium-term results also show no evidence of a difference in hip function or health-related quality of life in the 5 years following a total hip arthroplasty versus resurfacing arthroplasty. ISRCTN33354155. UKCRN 4093. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use

Readmissions after fast-track hip and knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik; Otte, Kristian Stahl; Kristensen, Billy B

2010-01-01

With the implementation of fast-track surgery with optimization of both logistical and clinical features, the postoperative convalescence has been reduced as functional milestones have been achieved earlier and consequently length of stay (LOS) in hospital has been reduced. However, it has been s...... speculated that a decrease in LOS may be associated with an increase in readmissions in general, including risk of dislocation after total hip arthroplasty (THA) or manipulation after total knee arthroplasty (TKA)....

Mechanoreceptors in Diseased Cervical Intervertebral Disc and Vertigo.

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Yang, Liang; Yang, Cheng; Pang, Xiaodong; Li, Duanming; Yang, Hong; Zhang, Xinwu; Yang, Yi; Peng, Baogan

2017-04-15

We collected the samples of cervical intervertebral discs from patients with vertigo to examine the distribution and types of mechanoreceptors in diseased cervical disc. The aim of this study was to determine whether mechanoreceptors are distributed more abundantly in cervical discs from patients with cervical spondylosis, and whether they are related to vertigo. Previous limited studies have found that normal cervical intervertebral discs are supplied with mechanoreceptors that have been considered responsible for proprioceptive functions. Several clinical studies have indicated that the patients with cervical spondylosis manifested significantly impaired postural control and subjective balance disturbance. We collected 77 samples of cervical discs from 62 cervical spondylosis patients without vertigo, 61 samples from 54 patients with vertigo, and 40 control samples from 8 cadaveric donors to investigate distribution of mechanoreceptors containing neurofilament (NF200) and S-100 protein immunoreactive nerve endings. The immunohistochemical investigation revealed that the most frequently encountered mechanoreceptors were the Ruffini corpuscles in all groups of cervical disc samples. They were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the diseased cervical discs from patients with vertigo in comparison with the discs from patients without vertigo and control discs. Only three Golgi endings were seen in the three samples from patients with vertigo. No Pacinian corpuscles were found in any samples of cervical discs. The diseased cervical discs from patients with vertigo had more abundant distribution of Ruffini corpuscles than other discs. A positive association between the increased number and ingrowth of Ruffini corpuscles in the diseased cervical disc and the incidence of vertigo in the patients with cervical spondylosis was found, which may indicate a key role of Ruffini corpuscles in the

Are galaxy discs optically thick?

International Nuclear Information System (INIS)

Disney, Michael; Davies, Jonathan; Phillipps, Steven

1989-01-01

We re-examine the classical optical evidence for the low optical depths traditionally assigned to spiral discs and argue that it is highly model-dependent and unconvincing. In particular, layered models with a physically thin but optically thick dust layer behave like optically thin discs. The opposite hypotheses, that such discs are optically thick is then examined in the light of modern evidence. We find it to be consistent with the near-infrared and IRAS observations, with the surface brightnesses, with the HI and CO column densities and with the Hα measurements. (author)

Analysis of the unicompartmental knee arthroplasty results

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S. A. Firsov

2015-01-01

Full Text Available In 2012-2014 total 67 unicompartmental arthroplasty surgeries with use of Oxford knee meniscal bearing were performed. The surgeries were performed by a single surgeon. Minimally invasive approach was used. All patients were evaluated clinically, radiographically and with Oxford Knee score scale, Knee Society score scale and functional scale. Obtained data was processed with nonparametric Mann-Whitney-Wilcoxon test. Results were processed using the statistical analysis application package SPSS, version 10.07. Analysis of of mid-term results showed that the average for Oxford Knee score increased from 16.4 (95% CI 9-23 to 41.3 (95% CI 29-47. Average for Knee Society score scale increased from 42.7 (95% CI 31-55 to 88.6 (95% CI 73-100. No occurrence of early postoperative complications have been reported. Statistically significant improvements of knee function in patients after unicompartmental arthroplasty have been observed. Unicompartmental arthroplasty currently can be considered as an advanced treatment option for medial knee joint pathology. Meniscal bearing cemented prostheses such as Oxford III are preferable.

Vascular complications of prosthetic inter-vertebral discs

OpenAIRE

Daly, Kevin J.; Ross, E. Raymond S.; Norris, Heather; McCollum, Charles N.

2006-01-01

Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had e...

Examination of turbine discs from nuclear power plants

International Nuclear Information System (INIS)

Czajkowski, C.J.; Weeks, J.R.

1982-01-01

Investigations were performed on a cracked turbine disc from the Cooper Nuclear Power Station, and on two failed turbine discs (governor and generator ends) from the Yankee-Rowe Nuclear Power Station. Cooper is a boiling water reactor (BWR) which went into commercial operation in July 1974, and Yankee-Rowe is a pressurized water reactor (PWR) which went into commercial operation in June 1961. Cracks were identified in the bore of the Cooper disc after 41,913 hours of operation, and the disc removed for repair. At Yankee-Rowe two discs failed after 100,000 hours of operation. Samples of the Cooper disc and both Yankee-Rowe disc (one from the governor and one from the generator end of the LP turbine) were sent to Brookhaven National Laboratory (BNL) for failure analysis

FAST-TRACK HIP AND KNEE ARTHROPLASTY (LITERATURE REVIEW

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A. M. Ageenko

2017-01-01

Full Text Available In the present paper the authors discuss the history of fast-track formation, its development and current status. Fast-track advantages in comparison to other rehabilitation options are analyzed. The focus is placed on methods of accelerated rehabilitation after total hip and knee arthroplasty in the leading European and American clinics. Fast-track protocols of surgical centers of Denmark and Hospital for special surgery in the US are described, factors that determine time of hospital stay after total hip and knee arthroplasty are considered, predictors of hospital stay and patients satisfaction after the surgery are examined. The paper reflects the results of the comparison of frequency of thromboembolic and other complications as well as readmission rate after traditional rehabilitation and after fast-track. The paper considers fast-track in bilateral total knee replacement. The authors conclude that further research on acceleration of rehabilitation and reduction of hospital stay after total hip and knee arthroplasty needs to be focused on the optimization of pain relief, especially after discharge, blood preservation techniques, supplementation of fluids loss and strengthening of muscles. Literature analysis demonstrated that the implementation of the Protocol for accelerated recovery after joint arthroplasty in Russia is at an insufficient level. Data of foreign multicenter studies during recent years indicate a high efficacy and safety of this technique in different groups of patients.

One-year incidence of prosthetic joint infection in total hip arthroplasty

DEFF Research Database (Denmark)

Gundtoft, P H; Pedersen, A B; Schønheyder, H C

2017-01-01

OBJECTIVE: To examine the trend of Prosthetic Joint Infections (PJI) following primary total hip arthroplasty (THA) and the antimicrobial resistance of the bacteria causing these infections. MATERIALS AND METHODS: We identified a population-based cohort of patients in the Danish Hip Arthroplasty...

Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load

International Nuclear Information System (INIS)

Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

1988-01-01

Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of 3 H 2 O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the 3 H 2 O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc

Revision for prosthetic joint infection following hip arthroplasty: Evidence from the National Joint Registry.

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Lenguerrand, E; Whitehouse, M R; Beswick, A D; Jones, S A; Porter, M L; Blom, A W

2017-06-01

We used the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR) to investigate the risk of revision due to prosthetic joint infection (PJI) for patients undergoing primary and revision hip arthroplasty, the changes in risk over time, and the overall burden created by PJI. We analysed revision total hip arthroplasties (THAs) performed due to a diagnosis of PJI and the linked index procedures recorded in the NJR between 2003 and 2014. The cohort analysed consisted of 623 253 index primary hip arthroplasties, 63 222 index revision hip arthroplasties and 7585 revision THAs performed due to a diagnosis of PJI. The prevalence, cumulative incidence functions and the burden of PJI (total procedures) were calculated. Overall linear trends were investigated with log-linear regression. We demonstrated a prevalence of revision THA due to prosthetic joint infection of 0.4/100 procedures following primary and 1.6/100 procedures following revision hip arthroplasty. The prevalence of revision due to PJI in the three months following primary hip arthroplasty has risen 2.3-fold (95% confidence interval (CI) 1.3 to 4.1) between 2005 and 2013, and 3.0-fold (95% CI 1.1 to 8.5) following revision hip arthroplasty. Over 1000 procedures are performed annually as a consequence of hip PJI, an increase of 2.6-fold between 2005 and 2013. Although the risk of revision due to PJI following hip arthroplasty is low, it is rising and, coupled with the established and further predicted increased incidence of both primary and revision hip arthroplasty, this represents a growing and substantial treatment burden. Cite this article : E. Lenguerrand, M. R. Whitehouse, A. D. Beswick, S. A. Jones, M. L. Porter, A. W. Blom. Revision for prosthetic joint infection following hip arthroplasty: Evidence from the National Joint Registry. Bone Joint Res 2017;6:391-398. DOI: 10.1302/2046-3758.66.BJR-2017-0003.R1. © 2017 Lenguerrand et al.

In vivo kinematics of a robot-assisted uni- and multi-compartmental knee arthroplasty.

Science.gov (United States)

Watanabe, Toshifumi; Abbasi, Ali Z; Conditt, Michael A; Christopher, Jennifer; Kreuzer, Stefan; Otto, Jason K; Banks, Scott A

2014-07-01

There is great interest in providing reliable and durable treatments for one- and two-compartment arthritic degeneration of the cruciate-ligament intact knee. One approach is to resurface only the diseased compartments with discrete unicompartmental components, retaining the undamaged compartment(s). However, placing multiple small implants into the knee presents a greater surgical challenge than total knee arthroplasty, so it is not certain that the natural knee mechanics can be maintained or restored. The goal of this study was to determine whether near-normal knee kinematics can be obtained with a robot-assisted multi-compartmental knee arthroplasty. Thirteen patients with 15 multi-compartmental knee arthroplasties using haptic robotic-assisted bone preparation were involved in this study. Nine subjects received a medial unicompartmental knee arthroplasty (UKA), three subjects received a medial UKA and patellofemoral (PF) arthroplasty, and three subjects received medial and lateral bi-unicondylar arthroplasty. Knee motions were recorded using video-fluoroscopy an average of 13 months (6-29 months) after surgery during stair and kneeling activities. The three-dimensional position and orientation of the implant components were determined using model-image registration techniques. Knee kinematics during maximum flexion kneeling showed femoral external rotation and posterior lateral condylar translation. All knees showed femoral external rotation and posterior condylar translation with flexion during the step activity. Knees with medial UKA and PF arthroplasty showed the most femoral external rotation and posterior translation, and knees with bicondylar UKA showed the least. Knees with accurately placed uni- or bi-compartmental arthroplasty exhibited stable knee kinematics consistent with intact and functioning cruciate ligaments. The patterns of tibiofemoral motion were more similar to natural knees than commonly has been observed in knees with total knee

INJURIES IN DISC GOLF - A DESCRIPTIVE CROSS-SECTIONAL STUDY

DEFF Research Database (Denmark)

Rahbek, Martin Amadeus; Nielsen, Rasmus Oestergaard

2016-01-01

BACKGROUND: Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported. PURPOSE: The purpose of the present study...... was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players. METHODS: The study was a cross-sectional study conducted on Danish disc-golf players. In May 2015, invitations to complete a web-based questionnaire were spread online via...... social media, and around disc-golf courses in Denmark. The questionnaire included questions regarding disc-golf participation and the characteristics of injuries acquired through disc golf participation. The data was analyzed descriptively. RESULTS: An injury prevalence of 13.3% (95% CI: 6.7% to 19...

Inferior outcome after hip resurfacing arthroplasty than after conventional arthroplasty. Evidence from the Nordic Arthroplasty Register Association (NARA) database, 1995 to 2007

DEFF Research Database (Denmark)

Johanson, Per-Erik; Fenstad, Anne Marie; Furnes, Ove

2010-01-01

The reported outcomes of hip resurfacing arthroplasty (HRA) vary. The frequency of this procedure in Denmark, Norway, and Sweden is low. We therefore determined the outcome of HRA in the NARA database, which is common to all 3 countries, and compared it to the outcome of conventional total hip...

Accuracy of the actuator disc-RANS approach for predicting the performance and wake of tidal turbines.

Science.gov (United States)

Batten, W M J; Harrison, M E; Bahaj, A S

2013-02-28

The actuator disc-RANS model has widely been used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large-scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade-element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results with those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94 per cent of the variation in the experimental velocity data measured on the centreline of the wake, therefore demonstrating that the actuator disc-RANS model is an accurate approach for modelling a turbine wake, and a conservative approach to predict performance and loads. It can therefore be applied to similar scenarios with confidence.

Assessment of patient functional performance in different knee arthroplasty designs during unconstrained squat.

Science.gov (United States)

Verdini, Federica; Zara, Claudio; Leo, Tommaso; Mengarelli, Alessandro; Cardarelli, Stefano; Innocenti, Bernardo

2017-01-01

In this paper, squat named by Authors unconstrained because performed without constrains related to feet position, speed, knee maximum angle to be reached, was tested as motor task revealing differences in functional performance after knee arthroplasty. It involves large joints ranges of motion, does not compromise joint safety and requires accurate control strategies to maintain balance. Motion capture techniques were used to study squat on a healthy control group (CTR) and on three groups, each characterised by a specific knee arthroplasty design: a Total Knee Arthroplasty (TKA), a Mobile Bearing and a Fixed Bearing Unicompartmental Knee Arthroplasty (respectively MBUA and FBUA). Squat was analysed during descent, maintenance and ascent phase and described by speed, angular kinematics of lower and upper body, the Center of Pressure (CoP) trajectory and muscle activation timing of quadriceps and biceps femoris. Compared to CTR, for TKA and MBUA knee maximum flexion was lower, vertical speed during descent and ascent reduced and the duration of whole movement was longer. CoP mean distance was higher for all arthroplasty groups during descent as higher was, CoP mean velocity for MBUA and TKA during ascent and descent. Unconstrained squat is able to reveal differences in the functional performance among control and arthroplasty groups and between different arthroplasty designs. Considering the similarity index calculated for the variables showing statistically significance, FBUA performance appears to be closest to that of the CTR group. III a.

Assessment of patient functional performance in different knee arthroplasty designs during unconstrained squat

Science.gov (United States)

Verdini, Federica; Zara, Claudio; Leo, Tommaso; Mengarelli, Alessandro; Cardarelli, Stefano; Innocenti, Bernardo

2017-01-01

Summary Background In this paper, squat named by Authors unconstrained because performed without constrains related to feet position, speed, knee maximum angle to be reached, was tested as motor task revealing differences in functional performance after knee arthroplasty. It involves large joints ranges of motion, does not compromise joint safety and requires accurate control strategies to maintain balance. Methods Motion capture techniques were used to study squat on a healthy control group (CTR) and on three groups, each characterised by a specific knee arthroplasty design: a Total Knee Arthroplasty (TKA), a Mobile Bearing and a Fixed Bearing Unicompartmental Knee Arthroplasty (respectively MBUA and FBUA). Squat was analysed during descent, maintenance and ascent phase and described by speed, angular kinematics of lower and upper body, the Center of Pressure (CoP) trajectory and muscle activation timing of quadriceps and biceps femoris. Results Compared to CTR, for TKA and MBUA knee maximum flexion was lower, vertical speed during descent and ascent reduced and the duration of whole movement was longer. CoP mean distance was higher for all arthroplasty groups during descent as higher was, CoP mean velocity for MBUA and TKA during ascent and descent. Conclusions Unconstrained squat is able to reveal differences in the functional performance among control and arthroplasty groups and between different arthroplasty designs. Considering the similarity index calculated for the variables showing statistically significance, FBUA performance appears to be closest to that of the CTR group. Level of evidence III a. PMID:29387646

Anteroposterior glide versus rotating platform low contact stress (LCS knee arthroplasty: a randomised controlled trial

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Wynn-Jones Charles

2007-08-01

Full Text Available Abstract Background Fifty thousand knee replacements are performed annually in the UK at an estimated cost of £150 million. Post-operative improvement depends on a number of factors including implant design and patient associated factors. To our knowledge there are no published study's comparing the results of AP glide and rotating platform designs of LCS knee arthroplasty. Therefore we feel that a study is required to investigate and compare the effects of two types of LCS total knee arthroplasty on joint proprioception and range of motion. Methods/Design Patients will be randomised to receive either a LCS AP glide or Rotating platform prosthesis. Clinical scores (Oxford knee score, American knee society score, EuroQol, range of motion and proprioception will be assessed prior to and at 3,6, 12 and 24 months after the operation. Proprioception will be assessed in terms of absolute error angle (mean difference between the target angle and the response angle. Knee angles will be measured in degrees using an electromagnetic tracking device, Polhemus 3Space Fastrak that detects positions of sensors placed on the test limb. Student's t-test will be used to compare the mean of two groups. Discussion Evidence is lacking concerning the best prosthesis to use for patients undergoing total knee replacement. This pragmatic randomised trial will test the null hypothesis that anteroposterior glide LCS knee arthroplasty does not result in better post operative knee motion and proprioception as compared to rotating platform LCS knee. Trial Registration ISRCTN52943804

Radiographic and scintigraphic evaluation of total knee arthroplasty

International Nuclear Information System (INIS)

Schneider, R.; Soudry, M.

1986-01-01

Various radiographic and scintigraphic methods are used to supplement clinical findings in the evaluation of total knee arthroplasty and its complications. Serial roentgenograms offer reliable information for diagnosing mechanical loosening. Wide and extensive radiolucency at the cement-bone interface and shift in position and alignment of prosthetic components can be seen in almost all cases by the time revision is necessary. Radiographic abnormalities are usually not present in acute infection, but are often present in chronic infection. Bone scanning has a high sensitivity for diagnosis of infection or loosening, but is nonspecific because increased uptake is often present around asymptomatic total knee arthroplasties with normal radiographs. Differential bone and Gallium scanning and scanning with Indium 111-labeled leukocytes have a greater specificity for diagnosis of infection than does bone or Gallium scanning alone. Routine radiographic and scintigraphic studies have shown a high incidence of deep vein thrombosis in the calf after total knee arthroplasty. Clinically significant pulmonary embolization is infrequent

Hydrodynamic forces on two moving discs

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Burton D.A.

2004-01-01

Full Text Available We give a detailed presentation of a flexible method for constructing explicit expressions of irrotational and incompressible fluid flows around two rigid circular moving discs. We also discuss how such expressions can be used to compute the fluid-induced forces and torques on the discs in terms of Killing drives. Conformal mapping techniques are used to identify a meromorphic function on an annular region in C with a flow around two circular discs by a Mobius transformation. First order poles in the annular region correspond to vortices outside of the two discs. Inflows are incorporated by putting a second order pole at the point in the annulus that corresponds to infinity.

Robotic-Assisted Unicompartmental Knee Arthroplasty: State-of-the Art and Review of the Literature.

Science.gov (United States)

Christ, Alexander B; Pearle, Andrew D; Mayman, David J; Haas, Steven B

2018-03-16

Unicompartmental knee arthroplasty is a successful treatment for unicompartmental knee osteoarthritis that has lower complication rates, faster recovery, and a more natural feeling knee compared to total knee arthroplasty. However, long-term survival has been a persistent concern. As more surgeon-controlled variables have been linked to survival, interest in robotic-assisted surgery has continued to grow. A review and synthesis of the literature on the subject of robotic-assisted unicompartmental knee arthroplasty was performed. We present the driving factors behind the development of robotic-assisted techniques in unicompartmental knee arthroplasty and the current state-of-the art. The ability of surgeons to achieve intraoperative targets with robotic assistance and the outcomes of robotic-assisted surgery are also described. Robotic-assisted surgery has become increasingly popular in unicompartmental knee arthroplasty, as it allows surgeons to more accurately and reproducibly plan and achieve operative targets during surgery. Cost remains a concern, and it remains to be seen whether robotic-assisted surgery will improve long-term survivorship after unicompartmental knee arthroplasty. Copyright © 2018 Elsevier Inc. All rights reserved.

Analgesic efficacy of local infiltration analgesia in hip and knee arthroplasty

DEFF Research Database (Denmark)

Andersen, Lasse Østergaard; Kehlet, H

2014-01-01

In recent years, there has been an increasing interest in local infiltration analgesia (LIA) as a technique to control postoperative pain. We conducted a systematic review of randomized clinical trials investigating LIA for total knee arthroplasty (TKA) and total hip arthroplasty (THA) to evaluate...

Role of patient characteristics for fast-track hip and knee arthroplasty

DEFF Research Database (Denmark)

Jørgensen, C.; Jacobsen, M; Søballe, Kjeld

2013-01-01

BACKGROUND: /st>Patient age and comorbidity have been found to increase the length of hospital stay (LOS), readmissions, and mortality after surgery, including in elective primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). Whether the same applies in fast-track THA and TKA...

Effect of Interbody Fusion on the Remaining Discs of the Lumbar Spine in Subjects with Disc Degeneration.

Science.gov (United States)

Ryu, Robert; Techy, Fernando; Varadarajan, Ravikumar; Amirouche, Farid

2016-02-01

To study effects (stress loads) of lumbar fusion on the remaining segments (adjacent or not) of the lumbar spine in the setting of degenerated adjacent discs. A lumbar spine finite element model was built and validated. The full model of the lumbar spine was a parametric finite element model of segments L 1-5 . Numerous hypothetical combinations of one-level lumbar spine fusion and one-level disc degeneration were created. These models were subjected to 10 Nm flexion and extension moments and the stresses on the endplates and consequently on the intervertebral lumbar discs measured. These values were compared to the stresses on healthy lumbar spine discs under the same load and fusion scenarios. Increased stress at endplates was observed only in the settings of L4-5 fusion and L3-4 disc degeneration (8% stress elevation at L2,3 in flexion or extension, and 25% elevation at L3,4 in flexion only). All other combinations showed less endplate stress than did the control model. For fusion at L3-4 and degeneration at L4-5 , the stresses in the endplates at the adjacent level inferior to the fused disc decreased for both loading disc height reductions. Stresses in flexion decreased after fusion by 29.5% and 25.8% for degeneration I and II, respectively. Results for extension were similar. For fusion at L2-3 and degeneration at L4-5 , stresses in the endplates decreased more markedly at the degenerated (30%), than at the fused level (14%) in the presence of 25% disc height reduction and 10 Nm flexion, whereas in extension stresses decreased more at the fused (24.3%) than the degenerated level (5.86%). For fusion at L3-4 and degeneration at L2-3 , there were no increases in endplate stress in any scenario. For fusion at L4-5 and degeneration at L3-4 , progression of degeneration from I to II had a significant effect only in flexion. A dramatic increase in stress was noted in the endplates of the degenerated disc (L3-4 ) in flexion for degeneration II. Stresses are greater

Revision total knee arthroplasty with the use of trabecular metal cones

DEFF Research Database (Denmark)

Jensen, Claus L; Petersen, Michael Mygind; Schrøder, Henrik

2012-01-01

"Trabecular Metal Cone" (TM Cone) (Zimmer, Inc, Warsaw, Ind) for reconstruction of bone loss in the proximal tibia during revision total knee arthroplasty is now optional. Forty patients were randomized to receive revision total knee arthroplasty with or without TM Cone (No TM Cone). The Anderson...

Cost-Effective Mobile-Based Healthcare System for Managing Total Joint Arthroplasty Follow-Up.

Science.gov (United States)

Bitsaki, Marina; Koutras, George; Heep, Hansjoerg; Koutras, Christos

2017-01-01

Long-term follow-up care after total joint arthroplasty is essential to evaluate hip and knee arthroplasty outcomes, to provide information to physicians and improve arthroplasty performance, and to improve patients' health condition. In this paper, we aim to improve the communication between arthroplasty patients and physicians and to reduce the cost of follow-up controls based on mobile application technologies and cloud computing. We propose a mobile-based healthcare system that provides cost-effective follow-up controls for primary arthroplasty patients through questions about symptoms in the replaced joint, questionnaires (WOMAC and SF-36v2) and the radiological examination of knee or hip joint. We also perform a cost analysis for a set of 423 patients that were treated in the University Clinic for Orthopedics in Essen-Werden. The estimation of healthcare costs shows significant cost savings (a reduction of 63.67% for readmission rate 5%) in both the University Clinic for Orthopedics in Essen-Werden and the state of North Rhine-Westphalia when the mobile-based healthcare system is applied. We propose a mHealth system to reduce the cost of follow-up assessments of arthroplasty patients through evaluation of diagnosis, self-monitoring, and regular review of their health status.

Nurse-led telephone follow-up after total knee arthroplasty

DEFF Research Database (Denmark)

Szöts, Kirsten; Konradsen, Hanne; Solgaard, Søren

2015-01-01

AIM AND OBJECTIVES: To generate information on how telephone follow-up consultations, structured by nursing status according to the VIPS-model, functioned after total knee arthroplasty. The objectives were to unfold the content of the telephone follow-ups according to the structure for nursing...... status and to explore the patients' views of the telephone follow-ups. BACKGROUND: The length of stay in hospital following total knee arthroplasty has fallen markedly, and patients now have to be responsible for their recovery from a very early stage. After discharge, patients may experience a variety...... Telephone follow-up was valued by total knee arthroplasties patients as representing a holistic approach and providing adequate information, counselling and support after discharge to home. Three categories were identified with regard to the patients' views: 'A means for reflection and provision of adequate...

Registro de artroplastias do ombro Shoulder arthroplasty records

Directory of Open Access Journals (Sweden)

Geraldo Motta Filho

2009-04-01

Full Text Available OBJETIVO: Determinar as características clínico-cirúrgicas referentes a 145 artroplastias do ombro realizadas no período entre julho de 2004 a dezembro de 2006. MÉTODOS: No período de estudo foram realizadas 145 artroplastias de ombro. Através de protocolo prospectivo, informações demográficas, da anamnese, exame físico e exame radiográfico foram armazenadas em um banco de dados. Os dados coletados foram organizados em três grandes grupos: doenças articulares degenerativas, fraturas e seqüelas traumáticas. Esses dados foram correlacionados a fim de definir o perfil epidemiológico dos pacientes, das lesões e artroplastias. RESULTADOS: Das 145 artroplastias de ombro realizadas 37% foram por seqüelas traumáticas, 30% por doença articular degenerativa e 33% com diagnóstico de fratura. Foram 12% artroplastias totais e 88% parciais. Ocorreram cinco complicações no pós-operatório recente. CONCLUSÃO: As artroplastias de ombro tornaram-se um procedimento frequente na prática ortopédica. Registros cirúrgicos são importantes a fim de demonstrar essa evolução progressiva e permitir avaliações de resultados clínicos no futuro.OBJECTIVE: The study's objective is to evaluate the characteristics and problems of patients who underwent shoulder arthroplasties between July 2004 and November 2006. METHODOLOGY: During the period of the study, 145 shoulder arthroplasties were performed. A prospective protocol was used for every patient; demographic, clinical and surgical procedure data were collected. All gathered data were included in the data base. The patients were divided in three major groups: fractures, degenerative diseases and trauma sequels. Information obtained from the data base was correlated in order to determine patients' epidemiologic, injuries, and surgical procedure profiles. RESULTS: Of the 145 shoulder arthroplasties performed, 37% presented trauma sequels, 30% degenerative diseases, and 33% proximal humerus

Preoperative prediction of potentially preventable morbidity after fast-track hip and knee arthroplasty

DEFF Research Database (Denmark)

Jørgensen, Christoffer C; Petersen, Morten Aa; Kehlet, Henrik

2016-01-01

. DESIGN: Prospective observational study. SETTING: Elective primary unilateral total hip and knee arthroplasty with prospectively collected preoperative patient characteristics; similar standardised fast-track protocols; evaluation of complications through discharge and medical records; and complete 90...... days follow-up through nationwide databases. PARTICIPANTS: 8373 consecutive unselected total hip arthroplasty (THA) and knee arthroplasty from January 2010 to November 2012. RESULTS: There were 557 procedures (6.4%) followed by potentially preventable complications resulting in hospitalisation >4 days...

Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength.

Science.gov (United States)

Sundseth, Jarle; Jacobsen, Eva A; Kolstad, Frode; Nygaard, Oystein P; Zwart, John A; Hol, Per K

2013-10-01

Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover(®) cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR. Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty. Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A "blur artifact ratio" was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level. The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The "blur artifact" induced at operated level was also more pronounced in the 3 Tesla MR. The artifact induced by the Discover(®) titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.

TREATMENT OF INFECTION AFTER TOTAL KNEE ARTHROPLASTY.

Science.gov (United States)

Cury, Ricardo de Paula Leite; Cinagawa, Eduardo Hitoshi Tsuge; Camargo, Osmar Pedro Arbix; Honda, Emerson Kiyoshi; Klautau, Giselle Burlamaqui; Salles, Mauro José Costa

2015-01-01

To identify and compare the rate of success of therapeutic modalities applied in surgeries for the treatment of infections associated with total knee arthroplasty (TKA), and to evaluate the functional outcome and pain in different therapeutic modalities by means of quality of life scores. We evaluated all patients who developed periprosthetic infection after TKA for primary or secondary osteoarthritis, in the period from January 1(st), 2008 to December 31(st), 2010. In the study period, 29 patients with TKA had infection, and 12 of these underwent debridement and retention of the prosthesis (D+R), seven received two-stage and six one-stage exchange arthroplasties, and four patients were treated with suppressive antibiotic therapy because they could not undergo another surgical procedure. The D+R, one-stage revision and two-stage revision success rates were 75%, 83.3%, and 100%, respectively. The best results of quality of life (QoL) and function occur in patients undergoing D+R. In contrast, the worst QoL and functional results were obtained in patients treated with two-stage revision arthroplasty. Level of Evidence II, Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

Fast-track revision knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B

2011-01-01

Abstract Background and purpose Fast-track surgery has reduced the length of hospital stay (LOS), morbidity, and convalescence in primary hip and knee arthroplasty (TKA). We assessed whether patients undergoing revision TKA for non-septic indications might also benefit from fast-track surgery...

Mechanical design criteria for intervertebral disc tissue engineering.

Science.gov (United States)

Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

2010-04-19

Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviors, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive, and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying where functional equivalence was achieved, and where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. Copyright 2009 Elsevier Ltd. All rights reserved.

Comparison of total hip arthroplasty in osteoarthritis of mechanical and rheumatologic causes

Science.gov (United States)

Ejnisman, Leandro; Leonhardt, Nathalia Zalc; Fernandes, Laura Fillipini Lorimier; Leonhardt, Marcos de Camargo; Vicente, José Ricardo Negreiros; Croci, Alberto Tesconi

2014-01-01

Objective: To compare the use of uncemented implants in total hip arthroplasty in patients with rheumathologic diseases and mechanical osteoarthrosis. Methods: We retrospectively evaluated 196 patients who were operated by the Hip and Arthroplasty Surgery Group of the IOT-HCFMUSP between 2005 and 2009. Patients were divided into two groups: mechanical causes (165 patients) and rheumathologic causes (31 patients). Groups were compared between each other in age, gender and follow-up time. Osseointegration rate and percentage of failure in arthroplasty were evaluated. Results: No statistically significant difference was found in osseointegration rates (in both femoral and acetabular components) in both groups. The rates of revision surgery and implant survival also did not show statistically significant differences. Conclusion: The use of uncemented total hip arthroplasty did not show worse results in rheumathologic patients. Level of Evidence III, Retrospective Case Control Study. PMID:24644419

Radiology in Gerard uncemented double cup arthroplasty

International Nuclear Information System (INIS)

Willems, W.J.; Rozing, P.M.; Obermann, W.R.

1988-01-01

A radiological follow-up was performed on 109 Gerard (uncemented) double cup arthroplasties, with special emphasis on shift of the femoral cup and protrusion of the acetabular cup, for which a new formula was introduced. Varus shift or axial collapse of the femoral cup played a major role in the failure of these cups. Fluoroscopic examination with video-tape recording seemed to be most helpful in determining abnormalities in this kind of arthroplasty. This examination revealed one normal and two abnormal types of movement, either between both cups or between acetabular cup and acetabular cavity. Those hips with normal movement showed a significantly better clinical score. 16 refs.; 6 figs

Hemorrhagic iliopsoas bursitis complicating well-functioning ceramic-on-ceramic total hip arthroplasty.

Science.gov (United States)

Park, Kyung Soon; Diwanji, Sanket R; Kim, Hyung Keun; Song, Eun Kyoo; Yoon, Taek Rim

2009-08-01

Iliopsoas bursitis has been increasingly recognized as a complication of total hip arthroplasty and is usually associated with polyethylene wear. Here, the authors report a case of hemorrhagic iliopsoas bursitis complicating an otherwise well-functioning ceramic-on-ceramic arthroplasty performed by minimal invasive modified 2-incision technique. The bursitis in turn resulted in femoral nerve palsy and femoral vein compression. In this report, there was no evidence to support that the bursitis was due to an inflammatory response to ceramic wear particles or any other wear particles originating from the total hip arthroplasty.

[Research progress on mechanical performance evaluation of artificial intervertebral disc].

Science.gov (United States)

Li, Rui; Wang, Song; Liao, Zhenhua; Liu, Weiqiang

2018-03-01

The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, in vitro specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using in vitro specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.

Alpine Skiing With total knee ArthroPlasty (ASWAP)

DEFF Research Database (Denmark)

Koesters, A.; Poetzelsberger, B.; Dela, F.

2015-01-01

The aim of this study was to monitor the long-term effects of skiing on health-related parameters and implant related factors like loosening and wear in patients with total knee arthroplasty. This paper describes the overall study design, general demographics, and physiological demand of the inte......The aim of this study was to monitor the long-term effects of skiing on health-related parameters and implant related factors like loosening and wear in patients with total knee arthroplasty. This paper describes the overall study design, general demographics, and physiological demand...

Disc type thermal actuator with straight beams for angular motion

International Nuclear Information System (INIS)

Anwar, M. Arefin; Packirisamy, Muthukumaran; Ahmed, A.K. Waiz

2013-01-01

Motion of a micro thermal actuator largely depends on its structural topology. This paper presents designs for a novel rotary type micro thermal actuator. This actuator has unique arrangement of hot segments around the cold segment. Upon application of potential difference, hot segments expand against the cold segment of disc and make the cold disc rotate about its center. This rotary motion can be used for various optical applications like, switching, attenuation and diffraction. The actuator has been fabricated using poly MUMPS process technology. An analytical model was used for predicting steady state temperature profile along the actuator length and rotational behavior of the cold disc under different applied voltages. A finite element analysis (FEA) was carried out to predict the behavior of the actuator by defining an air volume around the structure and also between structure and substrate. Finally testing was done for predicting feasibility of the actuator. Comparison of the rotational behavior obtained from both analytical model and FEA with that of obtained from testing shows close agreement. -- Highlights: ► Electro-thermo-mechanical modeling and verification of rotary micro thermal actuator. ► Modeling with conduction, convection and radiation modes for the air gap below 3 micron. ► In micro level, shape factor and material resistivity were estimated and verified through I–V characteristics. ► Two different designs of different shape factors were designed, fabricated and tested. ► The devices were fabricated using surface micromachining technology and tested for verification

Locally prepared antibiotic sensitivity discs: a substitute for imported ...

African Journals Online (AJOL)

Zones of inhibition were compared with those obtained from commercial antibiotic discs. Results obtained showed that discs prepared locally from antibiotic tablets, performed comparably with commercially obtained discs. There was no significant statistical difference between the two tested discs. We therefore recommend ...

[Eleven-Year Experience with Total Ankle Arthroplasty].

Science.gov (United States)

Popelka, S; Sosna, A; Vavřík, P; Jahoda, D; Barták, V; Landor, I

2016-01-01

PURPOSE OF THE STUDY Total joint replacement is one of the options in surgical treatment of advanced ankle arthritis. It allows the ankle to remain mobile but, unfortunately, it does not provide the same longevity as total knee or hip replacements. Therefore, decisions concerning the kind of treatment are very individual and depend on the clinical status and opinion of each patient. MATERIAL AND METHODS A total of 132 total ankle replacements were carried out in the period from 2004 to 2015. The prostheses used included the Ankle Evolutive System (AES) in 52 patients, Mobility Total Ankle System (DePuy) in 24 patients and, recently, Rebalance Total Ankle Replacement implant in 53 patients. Three patients allergic to metal received the Taric prosthesis. Revision arthroplasty using the Hintegra prosthesis was carried out in four patients. The outcome of arthroplasty was evaluated on the American Orthopaedic Foot and Ankle Society (AOFAS) scoring scale. Indications for total ankle arthroplasty included post-traumatic arthritis in 83 patients, rheumatoid arthritis in 37 and primary arthritis in 12 patients. There were 78 women and 54 men, with an average age of 55.6 years at the time of surgery. RESULTS The average follow-up was 6.1 years (1-11 years). The average AOFAS score of the whole group increased from 33.2 before surgery to 82.5 after it. The primary indication had an important role. Arthroplasty outcomes were poorer in patients with post-traumatic arthritis than in those with rheumatoid arthritis or primary arthritis. In patients with post-traumatic arthritis, the average AOFAS score rose to 78.6 due to restricted motion of the ankle, and some patients continued to have pain when walking. The average AOFAS score in a total of 49 patients who had rheumatoid arthritis or primary arthritis reached a value of 86.4. Post-operative complications were recorded in ten patients (7.6%) in whom part of the wound was healing by second intention. Ossification was also a

Imaging characteristics of noncontained migrating disc fragment and cyst

International Nuclear Information System (INIS)

Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G.; Loon, J. van; Calenbergh, F. van

2001-01-01

The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

Imaging characteristics of noncontained migrating disc fragment and cyst

Energy Technology Data Exchange (ETDEWEB)

Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G. [Dept. of Radiology, University Hospitals, Leuven (Belgium); Loon, J. van; Calenbergh, F. van [Dept. of Neurosurgery, University Hospitals, Leuven (Belgium)

2001-05-01

The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

Relationship of condylar position to disc position and morphology

Energy Technology Data Exchange (ETDEWEB)

Incesu, L.; Taskaya-Yilmaz, N. E-mail: nergizy@omu.edu.tr; Oeguetcen-Toller, M.; Uzun, E

2004-09-01

Introduction/objective: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. Methods and material: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. Results and discussion: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. Conclusion: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.

Thoracic spine disc-related abnormalities: longitudinal MR imaging assessment

Energy Technology Data Exchange (ETDEWEB)

Girard, Charles J.; Schweitzer, Mark E.; Morrison, William B.; Parellada, Joan A. [TJUH Radiology, Philadelphia, Pennsylvania (United States); Carrino, J.A. [Department of Radiology ASB-1, Harvard Medical School, Brigham and Women' s Hospital, L1, Room 002B, 75 Francis Street, MA 02115, Boston (United States)

2004-04-01

To describe and characterize the temporal changes in disc-related disorders of the thoracic spine using MR imaging. A retrospective longitudinal cohort study was carried out of 40 patients with two sequential thoracic spine MR images at variable intervals. The images were assessed for baseline presence of, new incidence of and changes in disc herniation, degenerative disc disease, endplate marrow signal alteration and Schmorl nodes. The range of follow-up was 4-149 weeks. Baseline presence was: disc herniation, 10% (49/480); degenerative disc disease, 14% (66/480); endplate marrow signal alteration, 2.3% (11/480); Schmorl nodes 9.6% (46/480). Most pre-existing lesions tended to remain unchanged. Herniations showed the most change, tending to improve in 27%. New incidence was: disc herniation, 1.5% (7/480), degenerative disc disease, 2% (10/480); endplate marrow signal alteration, 1.6% (8/480); Schmorl nodes, 2.1% (10/480). Disc degeneration was first visible at an 11-week interval and once established almost never changed over many weeks to months. Endplate signal alterations (Modic changes) were uncommon. Schmorl nodes show no change from baseline for up to 2 1/2 years. All findings predominated in the lower intervertebral levels from T6 to T10. The most prevalent thoracic spine disc-related findings are degeneration and herniation. Disc herniations predominate in the lower segments and are a dynamic phenomenon. Disc degeneration can be rapidly evolving but tends to remain unchanged after occurrence. Endplate marrow signal changes were an uncommon manifestation of thoracic disc disease. Schmorl nodes showed the least change over time. (orig.)

Use NASA GES DISC Data in ArcGIS

Science.gov (United States)

Yang, Wenli; Pham, Long B.; Kempler, Steve

2015-01-01

This presentation describes GIS relevant data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), GES DISC Services and Support for GIS Users, and use cases of GES DISC data in ArcGIS.

Conversion total hip arthroplasty: Primary or revision total hip arthroplasty

Science.gov (United States)

Schwarzkopf, Ran; Baghoolizadeh, Mahta

2015-01-01

Total hip arthroplasty (THA) is an increasingly common procedure among elderly individuals. Although conversion THA is currently bundled in a diagnosis related group (DRG) with primary THA, there is a lack of literature supporting this classification and it has yet to be identified whether conversion THA better resembles primary or revision THA. This editorial analyzed the intraoperative and postoperative factors and functional outcomes following conversion THA, primary THA, and revision THA to understand whether the characteristics of conversion THA resemble one procedure or the other, or are possibly somewhere in between. The analysis revealed that conversion THA requires more resources both intraoperatively and postoperatively than primary THA. Furthermore, patients undergoing conversion THA present with poorer functional outcomes in the long run. Patients undergoing conversion THA better resemble revision THA patients than primary THA patients. As such, patients undergoing conversion THA should not be likened to patients undergoing primary THA when determining risk stratification and reimbursement rates. Conversion THA procedures should be planned accordingly with proper anticipation of the greater needs both in the operating room, and for in-patient and follow-up care. We suggest that conversion THA be reclassified in the same DRG with revision THA as opposed to primary THA as a step towards better allocation of healthcare resources for conversion hip arthroplasties. PMID:26601055

The formation of planets by disc fragmentation

Directory of Open Access Journals (Sweden)

Stamatellos Dimitris

2013-04-01

Full Text Available I discuss the role that disc fragmentation plays in the formation of gas giant and terrestrial planets, and how this relates to the formation of brown dwarfs and low-mass stars, and ultimately to the process of star formation. Protostellar discs may fragment, if they are massive enough and can cool fast enough, but most of the objects that form by fragmentation are brown dwarfs. It may be possible that planets also form, if the mass growth of a proto-fragment is stopped (e.g. if this fragment is ejected from the disc, or suppressed and even reversed (e.g by tidal stripping. I will discuss if it is possible to distinguish whether a planet has formed by disc fragmentation or core accretion, and mention of a few examples of observed exoplanets that are suggestive of formation by disc fragmentation.

Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

Science.gov (United States)

Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

2017-09-01

Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

Persistent non-specific FDG uptake on PET imaging following hip arthroplasty

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Hongming; Chacko, Thomas K.; Hickeson, Marc; Stevenson, Karen; Feng, Qi; Ponzo, Fabio; Alavi, Abass [Division of Nuclear Medicine, Department of Radiology, The Hospital of University of Pennsylvania, 110 Donner Building, 3400 Spruce Street, Philadelphia, PA 19104 (United States); Garino, Jonathan P. [Department of Orthopedic Surgery, The Hospital of University of Pennsylvania, Philadelphia, PA 19802 (United States)

2002-10-01

Hip arthroplasty is a common surgical procedure, but the diagnosis of infection associated with hip arthroplasty remains challenging. Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown to be a promising imaging modality in settings where infection is suspected. However, inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations, which may erroneously be interpreted as sites of infection. The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time. Firstly, in a prospective study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time. Three FDG-PET scans were performed in each patient at about 3, 6 and 12 months post arthroplasty. Secondly, in a retrospective analysis, the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were reviewed. The history of arthroplasty and FDG-PET findings in the hip region were reviewed for this study. Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis. During the entire study period, all nine patients enrolled in the prospective study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur. Among the patients reviewed in the retrospective study, 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion. The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months (mean{+-}SD: 80.4{+-}86.2 months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be noted around the femoral head or neck portion of the

Outcomes After Interpositional Arthroplasty of the First Metatarsophalangeal Joint.

Science.gov (United States)

Aynardi, Michael C; Atwater, Lara; Dein, Eric J; Zahoor, Talal; Schon, Lew C; Miller, Stuart D

2017-05-01

For patients with hallux rigidus seeking a motion-sparing procedure, interposition arthroplasty is an alternative to fusion. The purpose of this study was to report patient outcomes after interpositional arthroplasty for hallux rigidus. All patients undergoing interpositional arthroplasty at our institution from 2001 to 2014 were identified and a retrospective chart review was performed. Follow-up was conducted through a telephone survey to obtain survivorship, satisfaction, and functional scores. Survivorship of the interpositional arthroplasty procedure was defined as no subsequent surgery on the hallux after the index procedure. Patients were excluded for incomplete records. Complications were recorded. From 2001 to 2014, 183 patients were identified. Of these, 14 were excluded for incomplete data, leaving 169 patients. Of these, 133 had an average follow-up of 62.2 months (range, 24.3 months to 151.2 months). The overall failure rate was 3.8% (5/133). Patient-reported outcome was rated as excellent in 65.4% (87/133) or good in 24.1% (32/133) of patients and fair or poor in 10.5% (14/133) of patients. Of 133 patients, 101 (76%) were able to return to fashionable or regular footwear. The infection rate was 1.5% (2/133). Patient-reported cock-up deformity of the first metatarsophalangeal joint (MTPJ) occurred in 4.5% (6/133) of patients. In addition, 17.3% (23/133) of patients reported metatarsalgia of the second or third MTPJ at the time of final follow-up, and there was no significant difference between interposition types ( P = .441). Interpositional arthroplasty for hallux rigidus was found to have excellent or good results in most patients at a mean follow-up of 62.2 months. Level IV, retrospective case series.

Intervertebral Disc Characteristic on Progressive Neurological Deficit

Directory of Open Access Journals (Sweden)

Farid Yudoyono

2017-09-01

Full Text Available Objective: To examine the intervertebral disc characteristic on magnetic resonance imaging (MRI in lumbar herniated disc (LHD patients with progressive neurological deficit. Methods: Patients were collected retrospectively from Dr. Hasan Sadikin General Hospital Database from 2011–2013 with LHD, had neurological deficit such as radiculopathy and cauda equine syndrome for less than four weeks with a positive sign confirmed by neurological examination and confirmatory with MRI examination. Results: A total of 14 patients with lumbar herniated disc disease (10 males, 4 females suffered from progressive neurological deficit with an average age of (52.07±10.9 years old. Early disc height was 9.38±0.5 mm and progressive neurological deficit state disc height was 4.03±0.53 mm, which were significantly different statisticaly (p<0.01. Symptoms of radiculopathy were seen in 11 patients and cauda equine syndrome in three patients. Modic changes grade 1 was found in five patients, grade 2 in eight patients,grade 3 in one patient, Pfirmman grade 2 in eleven patients and grade 3 in three patients. Thecal sac compression 1/3 compression was seen in four patients and 2/3 compression in ten patients. Conclusions: Neurosurgeon should raise concerns on the characteristic changes of intervertebral disc in magnetic resonance imaging examination to avoid further neural injury in lumbar herniated disc patients.

The Popularity of Outcome Measures for Hip and Knee Arthroplasties.

Science.gov (United States)

Lovelock, Thomas M; Broughton, Nigel S; Williams, Cylie M

2018-01-01

The optimal methods of determining outcomes following hip and knee arthroplasty remain controversial. The objectives of this study were to determine the most frequently used outcome measures in randomized controlled trials (RCT) and study protocols registered with clinical trials registries (CTR) on hip and knee arthroplasty. A systematic search strategy was undertaken to identify the outcome measures used in RCT and CTR following joint arthroplasty. Databases searched included Embase, Ovid MEDLINE (including In-Process), Cochrane Central Register of Controlled Trials, CINAHL Plus, clinicaltrials.gov, ISRCTN registry, and ANZCTR. Differences in the use of outcome measures between RCT and CTR were assessed using logistic regression. There were 291 RCT and 113 CTR on hip arthroplasty and 452 RCT and 184 CTR on knee arthroplasty that met the inclusion criteria. The most popular outcome measures were the Harris Hip Score and the Knee Society Score. Multiple outcome measures were used in greater than 50% of the included studies. The Oxford Hip Score, Oxford Knee Score, EuroQol-5D, and Knee Injury and Osteoarthritis Outcome Score (all P < .001) were used in significantly more CTR than RCT. There is a clear preference for the use of the Harris Hip Score and Knee Society Score, contrary to existing international guidelines and reviews on the topic. Both measures require clinician input, which potentially influences their validity and increases their overall administration cost. Some patient-reported outcome measures, such as the Oxford Hip and Knee Scores, EuroQol-5D, and KOOS, appear to be increasing in popularity. Copyright © 2017 Elsevier Inc. All rights reserved.

Two-stage exchange knee arthroplasty: does resistance of the infecting organism influence the outcome?

Science.gov (United States)

Kurd, Mark F; Ghanem, Elie; Steinbrecher, Jill; Parvizi, Javad

2010-08-01

Periprosthetic joint infection after TKA is a challenging complication. Two-stage exchange arthroplasty is the accepted standard of care, but reported failure rates are increasing. It has been suggested this is due to the increased prevalence of methicillin-resistant infections. We asked the following questions: (1) What is the reinfection rate after two-stage exchange arthroplasty? (2) Which risk factors predict failure? (3) Which variables are associated with acquiring a resistant organism periprosthetic joint infection? This was a case-control study of 102 patients with infected TKA who underwent a two-stage exchange arthroplasty. Ninety-six patients were followed for a minimum of 2 years (mean, 34.5 months; range, 24-90.1 months). Cases were defined as failures of two-stage exchange arthroplasty. Two-stage exchange arthroplasty was successful in controlling the infection in 70 patients (73%). Patients who failed two-stage exchange arthroplasty were 3.37 times more likely to have been originally infected with a methicillin-resistant organism. Older age, higher body mass index, and history of thyroid disease were predisposing factors to infection with a methicillin-resistant organism. Innovative interventions are needed to improve the effectiveness of two-stage exchange arthroplasty for TKA infection with a methicillin-resistant organism as current treatment protocols may not be adequate for control of these virulent pathogens. Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Cirrhosis patients have increased risk of complications after hip or knee arthroplasty

DEFF Research Database (Denmark)

Deleuran, Thomas; Vilstrup, Hendrik; Overgaard, Søren

2015-01-01

Background and purpose: The risk of complications in cirrhosis patients after orthopedic surgery is unclear. We examined this risk after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Patients and methods: Using Danish healthcare registries, we identified all Danish residents who...

Effect of distraction arthroplasty on osteoarthritic goat models of the articular cartilage

Directory of Open Access Journals (Sweden)

Rizky N.H. Putro

2013-05-01

Full Text Available Background: Osteoarthritis (OA is the most common knee degenerative disease, the number of OA patients increases along with the increase of life expectancy. Distraction arthroplasty is a less invasive alternatif for OA management by releaving mechanical stress while maintaining intermitten joint fluid pressure changes, thus halting the OA destructive cycle and inducing repair. This study aims to evaluate the anatomical and histopathological changes after distraction arthroplasty on osteoarthritic animal models.Methods: The study was performed on 32 goat stiffle joint (16 goats with mechanically induced OA by lateral meniscectomy. During the study 6 goats were decreased. Distraction arthroplasty was performed using external fixation on 10 knees for 4 weeks, and the contralateral knees left untreated. The knees were anatomically and histopathologically examined using International Cartilage Repair Society (ICRS staging and Osteoarthritis Research Society International (OARSI scoring. The differences of the anatomical and histopathological changes are tested for significance using the Wilcoxon test.Results: There was anatomical and histopathological worsening of the OA on treated knees. The anatomical difference assessed using ICRS stage gave median values of 1.5 and 2.5 respectively (p < 0.002. The histopathological difference assessed using OARSI scoring was significant (6 vs 10; p < 0.002.Conclusion: Distraction arthroplasty in OA goat models in this study, worsens the OA instead of inducing repair. Further studies are required to find out a convincing biological basis of distraction arthroplasty as an alternative treatment for OA. (Med J Indones. 2013;22:64-9Keywords: Animal model, distraction arthroplasty, osteoarthritis

The association between metal allergy, total knee arthroplasty, and revision

DEFF Research Database (Denmark)

Münch, Henrik J; Jakobsen, Stig Storgaard; Olesen, Jens T

2015-01-01

BACKGROUND AND PURPOSE: It is unclear whether delayed-type hypersensitivity reactions against implanted metals play a role in the etiopathogenesis of malfunctioning total knee arthroplasties. We therefore evaluated the association between metal allergy, defined as a positive patch test reaction...... to common metal allergens, and revision surgery in patients who underwent knee arthroplasty. PATIENTS AND METHODS: The nationwide Danish Knee Arthroplasty Register, including all knee-implanted patients and revisions in Denmark after 1997 (n = 46,407), was crosslinked with a contact allergy patch test......, the prevalence of cobalt and chromium allergy was markedly higher. Metal allergy that was diagnosed before implant surgery appeared not to increase the risk of implant failure and revision surgery. INTERPRETATION: While we could not confirm that a positive patch test reaction to common metals is associated...

Use of massive structural allograft in revision septic hip arthroplasty

International Nuclear Information System (INIS)

Imran Ilyas; Morgan, F.; David, A.

1999-01-01

The reconstruction of failed septic hip arthroplasty with the use of massive osseous allograft segments is reported in ten patients. All of these patients had a two-stage procedure with an interval Girdlestone arthroplasty separating the initial demolition from the subsequent reconstruction. The mean follow-up was 58 months (range 36 to 98 months) and the most common pathogen isolated was Staphylococcus epidermidis. The mean preoperative modified Harris hip score was 27 points (range 9 to 58) and the mean postoperative score was 73 points (range 53 to 92). There was one patient who required an additional procedure not related to allograft use. There has been no case of recurrence of infection. We conclude that the revision of septic hip arthroplasty in the use of massive allografts do not have to be mutually exclusive events

Only marginal alignment of disc galaxies

Science.gov (United States)

Andrae, René; Jahnke, Knud

2011-12-01

Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understanding the formation of this type of galaxies. The tidal-torque theory aims to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness, i.e. alignment of disc galaxies, on short distance scales of 1 Mpc h-1. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering these correlations but are overly optimistic in the reported level of statistical significance of the detections. Errors in redshift, ellipticity and morphological classifications were not taken into account, although they have a significant impact. We explain how to rigorously propagate all the important errors through the estimation process. Analysing disc galaxies in the Sloan Digital Sky Survey (SDSS) data base, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distance scales of 1 Mpc h-1 are plausible but not statistically significant. Current data appear not good enough to constrain parameters of theory. This result agrees with a simple hypothesis test in the Local Group, where we also find no evidence for disc alignment. Moreover, we demonstrate that ellipticity estimates based on second moments are strongly biased by galactic bulges even for Scd galaxies, thereby corrupting correlation estimates and overestimating the impact of disc alignment on weak-lensing studies. Finally, we discuss the potential of future sky surveys. We argue that photometric redshifts have too large errors, i.e. PanSTARRS and LSST cannot be used. Conversely, the EUCLID project will not cover the relevant redshift regime. We also discuss the potentials and problems of front-edge classifications of galaxy discs in order to improve the autocorrelation estimates of angular-momentum orientation.

Vibroacoustography for the assessment of total hip arthroplasty

Directory of Open Access Journals (Sweden)

Hermes A.S. Kamimura

2013-04-01

Full Text Available OBJECTIVES: This paper proposes imaging with 3-dimensional vibroacoustography for postoperatively assessing the uncovered cup area after total hip arthroplasty as a quantitative criterion to evaluate implant fixation. METHODS: A phantom with a bone-like structure covered by a tissue-mimicking material was used to simulate a total hip arthroplasty case. Vibroacoustography images of the uncovered cup region were generated using a two-element confocal ultrasound transducer and a hydrophone inside a water tank. Topological correction based on the geometry of the implant was performed to generate a 3-dimensional representation of the vibroacoustography image and to accurately evaluate the surface. The 3-dimensional area obtained by the vibroacoustography approach was compared to the area evaluated by a 3-dimensional motion capture system. RESULTS: The vibroacoustography technique provided high-resolution, high-contrast, and speckle-free images with less sensitivity to the beam incidence. Using a 3-dimensional-topology correction of the image, we accurately estimated the uncovered area of the implant with a relative error of 8.1% in comparison with the motion capture system measurements. CONCLUSION: Measurement of the cup coverage after total hip arthroplasty has not been well established; however, the covered surface area of the acetabular component is one of the most important prognostic factors. The preliminary results of this study show that vibroacoustography is a 3-dimensional approach that can be used to postoperatively evaluate total hip arthroplasty. The favorable results also provide an impetus for exploring vibroacoustography in other bone or implant surface imaging applications.

Evaluation of bone and disc configuration in TMJ internal derangement

International Nuclear Information System (INIS)

Park, Cheol Woo; Hwang, Eui Hwan; Lee, Sang Rae

2001-01-01

To investigate bone and disc configuration on MR images in internal derangement related to age. MR images of 150 TMJs in 107 patients were analyzed to determine the morphologic changes. Two groups were distinguished to be correlated with age. Group 1 consisted of TMJs that were diagnosed as having anterior disc displacement with reduction (ADDwR), and Group 2 consisted of TMJs that were diagnosed as having anterior disc displacement without reduction (ADDwR). We assessed the configuration of the articular disc, degree of anterior disc displacement, and osseous changes of TMJs. The third decade (83 of 150 joints) was most frequent in this study. In the ADDwR group biconcave disc was most frequent at all ages except fifth decade, but in the ADDwoR group deformed discs was most frequent at third and forth decades. In the ADDwR group slightly displaced discs was most frequent at all ages, but in the ADDwoR group severely displaced discs was most frequent at second decade, and the degree of disc displacement was increased with aging over 30 years of age. TM joints showed osseous changes in 17% of the ADDwR group, and in 30% of the ADDwoR group. MR findings of osseous changes of the TMJ were not found to be significantly correlated with age. The prevalence of deformation of disc, displacement of disc, and osseous changes of TMJ was higher in the ADDwoR group than in the ADDwR group. MR findings of disc configuration and degree of disc displacement were found to be correlated with age

Enoxaparin-induced skin necrosis at injection site after total knee arthroplasty

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Max Haffner, BS

2018-03-01

Full Text Available Enoxaparin is a widely used low-molecular-weight heparin for perioperative thromboembolic prophylaxis. Enoxaparin-induced skin necrosis in the setting of arthroplasty has been rarely reported in the literature with varying outcomes and management decisions. Our patient developed skin necrosis at his injection site and thrombocytopenia 10 days following left total knee arthroplasty surgery and after receiving subcutaneous Lovenox injections postoperatively. The patient was started on an alternative anticoagulation based on a high suspicion for heparin-induced thrombocytopenia and the wound was monitored without surgical debridement. Our case highlights the key clinical management decisions when facing this potentially life-threatening adverse reaction. Keywords: Lovenox, Enoxaparin, Skin necrosis, Adverse reaction, Arthroplasty

Efficacy in Deep Vein Thrombosis Prevention With Extended Mechanical Compression Device Therapy and Prophylactic Aspirin Following Total Knee Arthroplasty: A Randomized Control Trial.

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Snyder, Mark A; Sympson, Alexandra N; Scheuerman, Christina M; Gregg, Justin L; Hussain, Lala R

2017-05-01

Aspirin at 325 mg twice daily is now included as a nationally approved venous thromboembolism (VTE) prophylaxis protocol for low-risk total knee arthroplasty (TKA) patients. The purpose of this study is to examine whether there is a difference in deep vein thrombosis (DVT) occurrence after a limited tourniquet TKA using aspirin-based prophylaxis with or without extended use of mechanical compression device (MCD) therapy. One hundred limited tourniquet TKA patients, whose DVT risk was managed with aspirin 325 mg twice daily for 3 weeks, were randomized to either using an MCD during hospitalization only or extended use at home up to 6 weeks postoperatively. Lower extremity duplex venous ultrasonography (LEDVU) was completed on the second postoperative day, 14 days postoperatively, and at 3 months postoperatively to confirm the absence of DVT after treatment. The DVT rate for the postdischarge MCD therapy group was 0% and 23.1% for the inpatient MCD group (P aspirin for 3 weeks postoperatively, and on MCD therapy for up to 6 weeks postoperatively experienced superior DVT prophylaxis than patients receiving MCD therapy only as an inpatient (P aspirin and extended-use MCD further validates this type of prophylaxis in low DVT risk TKA patients. Copyright © 2016 Elsevier Inc. All rights reserved.

A computational study of intervertebral disc degeneration in relation to changes in regional tissue composition and disc nutrition

OpenAIRE

Ruiz Wills, Carlos

2015-01-01

Up to 85% of the world population suffers from low back pain, a clinical condition often related to the intervertebral disc (IVD) degeneration (DD). Altered disc cell nutrition affects cell viability and can generate catabolic cascades that degrade the extracellular matrix (ECM). Also, a major degenerative biochemical change in the disc is the proteoglycan (PG) loss, which affects the osmotic pressure and hydration that is critical for cell nutrition. However, the relationship between biochem...

Schrödinger evolution of self-gravitating discs

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Batygin, Konstantin

2018-04-01

An understanding of the long-term evolution of self-gravitating discs ranks among the classic outstanding problems of astrophysics. In this work, we show that the secular inclination dynamics of a geometrically thin quasi-Keplerian disc, with a surface density profile that scales as the inverse square-root of the orbital radius, are described by the time-dependent Schrödinger equation. Within the context of this formalism, nodal bending waves correspond to the eigenmodes of a quasi-particle's wavefunction, confined in an infinite square well with boundaries given by the radial extent of the disc. We further show that external secular perturbations upon self-gravitating discs exhibit a mathematical similarity to quantum scattering theory. Employing this framework, we derive an analytic criterion for the gravitational rigidity of a nearly-Keplerian disc under external perturbations. Applications of the theory to circumstellar discs and Galactic nuclei are discussed.

Evidence for accreted component in the Galactic discs

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Xing, Q. F.; Zhao, G.

2018-06-01

We analyse the distribution of [Mg/Fe] abundance in the Galactic discs with F- and G-type dwarf stars selected from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) archive. The sample stars are assigned into different stellar populations by using kinematic criteria. Our analysis reveals the chemical inhomogeneities in the Galactic thick disc. A few of metal-poor stars in the thick disc exhibit relatively low [Mg/Fe] abundance in respect to the standard thick-disc sample. The orbital eccentricities and maximum Galactocentric radii of low-α metal-poor stars are apparently greater than that of high-α thick-disc stars. The orbital parameters and chemical components of low-α stars in the thick disc suggest that they may have been formed in regions with low star formation rate that were located at large distances from the Galactic centre, such as infalling dwarf spheroidal galaxies.

Gas Modelling in the Disc of HD 163296

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Tilling, I.; Woitke, P.; Meeus, G.; Mora, A.; Montesinos, B.; Riviere-Marichalar, P.; Eiroa, C.; Thi, W. -F.; Isella, A.; Roberge, A.;

Heterotopic bone formation following total shoulder arthroplasty

DEFF Research Database (Denmark)

Kjaersgaard-Andersen, P.; Frich, Lars Henrik; Sjøbjerg, J.O.

1989-01-01

The incidence and location of heterotopic bone formation following total shoulder arthroplasty were evaluated in 58 Neer Mark-II total shoulder replacements. One year after surgery, 45% had developed some ectopic ossification. In six shoulders (10%) the ossifications roentgenographically bridged...... the glenohumeral and/or the glenoacromial space. There was no correlation between shoulder pain and the development of ossification. Shoulders with grade III heterotopic bone formation had a limited range of active elevation compared with shoulders without or with only a milder lesion. Men and patients...... with osteoarthritis of the shoulder joint were significantly disposed to the development of heterotopic bone. Heterotopic bone formation following total shoulder arthroplasty is frequent, but disabling heterotopic ossifications seem to be rare....

DZ Chamaeleontis: a bona fide photoevaporating disc

Science.gov (United States)

Canovas, H.; Montesinos, B.; Schreiber, M. R.; Cieza, L. A.; Eiroa, C.; Meeus, G.; de Boer, J.; Ménard, F.; Wahhaj, Z.; Riviere-Marichalar, P.; Olofsson, J.; Garufi, A.; Rebollido, I.; van Holstein, R. G.; Caceres, C.; Hardy, A.; Villaver, E.

2018-02-01

Context. DZ Cha is a weak-lined T Tauri star (WTTS) surrounded by a bright protoplanetary disc with evidence of inner disc clearing. Its narrow Hα line and infrared spectral energy distribution suggest that DZ Cha may be a photoevaporating disc. Aims: We aim to analyse the DZ Cha star + disc system to identify the mechanism driving the evolution of this object. Methods: We have analysed three epochs of high resolution optical spectroscopy, photometry from the UV up to the sub-mm regime, infrared spectroscopy, and J-band imaging polarimetry observations of DZ Cha. Results: Combining our analysis with previous studies we find no signatures of accretion in the Hα line profile in nine epochs covering a time baseline of 20 yr. The optical spectra are dominated by chromospheric emission lines, but they also show emission from the forbidden lines [SII] 4068 and [OI] 6300Å that indicate a disc outflow. The polarized images reveal a dust depleted cavity of 7 au in radius and two spiral-like features, and we derive a disc dust mass limit of Mdust 80 MJup) companions are detected down to 0.̋07 ( 8 au, projected). Conclusions: The negligible accretion rate, small cavity, and forbidden line emission strongly suggests that DZ Cha is currently at the initial stages of disc clearing by photoevaporation. At this point the inner disc has drained and the inner wall of the truncated outer disc is directly exposed to the stellar radiation. We argue that other mechanisms like planet formation or binarity cannot explain the observed properties of DZ Cha. The scarcity of objects like this one is in line with the dispersal timescale (≲105 yr) predicted by this theory. DZ Cha is therefore an ideal target to study the initial stages of photoevaporation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 097.C-0536. Based on data obtained from the ESO Science Archive Facility under request number 250112.

Low risk of thromboembolic complications after fast-track hip and knee arthroplasty

DEFF Research Database (Denmark)

Husted, Henrik; Otte, Niels Kristian Stahl; Kristensen, Billy B

2010-01-01

Pharmacological prophylaxis can reduce the risk of deep venous thrombosis (DVT), pulmonary embolism (PE), and death, and it is recommended 10–35 days after total hip arthroplasty (THA) and at least 10 days after total knee arthroplasty (TKA). However, early mobilization might also reduce the risk...

Arthroscopic bursectomy for recalcitrant trochanteric bursitis after hip arthroplasty.

Science.gov (United States)

Van Hofwegen, Christopher; Baker, Champ L; Savory, Carlton G; Baker, Champ L

2013-01-01

This study evaluated the use of arthroscopic bursectomy for pain relief in patients with trochanteric bursitis after hip arthroplasty. In this retrospective case series of 12 patients undergoing arthroscopic treatment of recalcitrant trochanteric bursitis after hip arthroplasty, outcomes were assessed via phone interview with a numeric pain rating scale from 1 to 10 and were compared with preoperative pain ratings. Patients were asked the percentage of time they had painless hip function and whether they would have the surgery again. At an average 36-month follow-up (range, 4-85 months), the average numeric pain scale rating improved from 9.3 to 3.3. At an average of 62% of the time, patients had painless use of the hip. Ten of 12 patients in the study felt the pain relief gained was substantial enough to warrant having procedure again. In these patients, arthroscopic bursectomy was a viable option for patients with recalcitrant bursitis after hip arthroplasty.

Porous metal cones: gold standard for massive bone loss in complex revision knee arthroplasty? A systematic review of current literature.

Science.gov (United States)

Divano, Stefano; Cavagnaro, Luca; Zanirato, Andrea; Basso, Marco; Felli, Lamberto; Formica, Matteo

2018-04-18

Revision knee arthroplasty is increasing, and in that case, bone loss management is still a challenging problem. In the last years, the body of literature and interest surrounding porous metal cones has grown, but few systematic evaluations of the existing evidence have been performed. The aim of our systematic review is to collect and critically analyze the available evidence about metal cones in revision knee arthroplasty especially focusing our attention on indications, results, complications, and infection rate of these promising orthopaedic devices. We performed a systematic review of the available English literature, considering the outcomes and the complications of tantalum cones. The combinations of keyword were "porous metal cones", "knee revision", "bone loss", "knee arthroplasty", "periprosthetic joint infection", and "outcome". From the starting 312 papers available, 20 manuscripts were finally included. Only one included study has a control group. The main indication for metal cones is type IIb and III defects according AORI classification. Most of the papers show good clinical and radiological outcomes with low rate of complications. The examined studies provide encouraging clinical and radiological short-to-mid-term outcomes. Clinical studies have shown a low rate of aseptic loosening, intraoperative fractures, infection rate and a lower failure rate than the previous treatment methods. Higher quality papers are needed to draw definitive conclusions about porous metal cones.

Hip resurfacing arthroplasty in treatment of avascular necrosis of the femoral head.

Science.gov (United States)

Pyda, Michał; Koczy, Bogdan; Widuchowski, Wojciech; Widuchowska, Małgorzata; Stołtny, Tomasz; Mielnik, Michał; Hermanson, Jacek

2015-01-25

Hip resurfacing is a conservative type of total hip arthroplasty but its use is controversial, especially in patients with osteonecrosis. The aim of this study was analysis of the clinical and radiographic outcomes of hip resurfacing in patients with osteonecrosis. Between 2007 and 2008, 30 hip resurfacing arthroplasties were performed due to osteoarthritis secondary to avascular necrosis of femoral head staged as Ficat III and IV. Patients were qualified to resurfacing arthroplasty when the extent of avascular necrosis using Kerboul's method was avascular necrosis and head-neck junction was >20°. All patients were evaluated clinically and radiologically before and 60 months after the operation. The mean Harris Hip Score (HHS) score increased from 47.8 to 94.25 (p<0.05). Physical activity level (University of California, Los Angeles activity score--UCLA activity score) improved from 3.7 to 7.55 (p<0.05). No implant migration was observed. Management of osteonecrosis of the hip with resurfacing arthroplasty seems to be effective in strictly-selected patients.

Patient gender affects the referral and recommendation for total joint arthroplasty.

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Borkhoff, Cornelia M; Hawker, Gillian A; Wright, James G

2011-07-01

Rates of use of total joint arthroplasty among appropriate and willing candidates are lower in women than in men. A number of factors may explain this gender disparity, including patients' preferences for surgery, gender bias influencing physicians' clinical decision-making, and the patient-physician interaction. We propose a framework of how patient gender affects the patient and physician decision-making process of referral and recommendation for total joint arthroplasty and consider potential interventions to close the gender gap in total joint arthroplasty utilization. The process involved in the referral and recommendation for total joint arthroplasty involves eight discrete steps. A systematic review is used to describe the influence of patient gender and related clinical and nonclinical factors at each step. WHERE ARE WE NOW?: Patient gender plays an important role in the process of referral and recommendation for total joint arthroplasty. Female gender primarily affects Steps 3 through 8, suggesting barriers unique to women exist in the patient-physician interaction. WHERE DO WE NEED TO GO?: Developing and evaluating interventions that improve the quality of the patient-physician interaction should be the focus of future research. HOW DO WE GET THERE?: Potential interventions include using decision support tools that facilitate shared decision-making between patients and their physicians and promoting cultural competency and shared decision-making skills programs as a core component of medical education. Increasing physicians' acceptance and awareness of the unconscious biases that may be influencing their clinical decision-making may require additional skills programs.

Magnetic resonance imaging of intervertebral disc degeneration

International Nuclear Information System (INIS)

Maeda, Hiroshi; Noguchi, Masao; Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi.

1993-01-01

The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.)

Magnetic resonance imaging of intervertebral disc degeneration

Energy Technology Data Exchange (ETDEWEB)

Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

1993-02-01

The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

Patients' decision making in total knee arthroplasty: a systematic review of qualitative research.

Science.gov (United States)

Barlow, T; Griffin, D; Barlow, D; Realpe, A

2015-10-01

A patient-centred approach, usually achieved through shared decision making, has the potential to help improve decision making around knee arthroplasty surgery. However, such an approach requires an understanding of the factors involved in patient decision making. This review's objective is to systematically examine the qualitative literature surrounding patients' decision making in knee arthroplasty. A systematic literature review using Medline and Embase was conducted to identify qualitative studies that examined patients' decision making around knee arthroplasty. An aggregated account of what is known about patients' decision making in knee arthroplasties is provided. Seven studies with 234 participants in interviews or focus groups are included. Ten themes are replicated across studies, namely: expectations of surgery; coping mechanisms; relationship with clinician; fear; pain; function; psychological implications; social network; previous experience of surgery; and conflict in opinions. This review is helpful in not only directing future research to areas that are not understood, or require confirmation, but also in highlighting areas that future interventions could address. These include those aimed at delivering information, which are likely to affect the satisfaction rate, demand, and use of knee arthroplasties. Cite this article: Bone Joint Res 2015;4;163-169. ©2015 Griffin.

AQUILA: assessment of quality in lower limb arthroplasty. An expert Delphi consensus for total knee and total hip arthroplasty.

Science.gov (United States)

Pijls, Bart G; Dekkers, Olaf M; Middeldorp, Saskia; Valstar, Edward R; van der Heide, Huub J L; Van der Linden-Van der Zwaag, Henrica M J; Nelissen, Rob G H H

2011-07-22

In the light of both the importance and large numbers of case series and cohort studies (observational studies) in orthopaedic literature, it is remarkable that there is currently no validated measurement tool to appraise their quality. A Delphi approach was used to develop a checklist for reporting quality, methodological quality and generalizability of case series and cohorts in total hip and total knee arthroplasty with a focus on aseptic loosening. A web-based Delphi was conducted consisting of two internal rounds and three external rounds in order to achieve expert consensus on items considered relevant for reporting quality, methodological quality and generalizability. The internal rounds were used to construct a master list. The first external round was completed by 44 experts, 35 of them completed the second external round and 33 of them completed the third external round. Consensus was reached on an 8-item reporting quality checklist, a 6-item methodological checklist and a 22-item generalizability checklist. Checklist for reporting quality, methodological quality and generalizability for case series and cohorts in total hip and total knee arthroplasty were successfully created through this Delphi. These checklists should improve the accuracy, completeness and quality of case series and cohorts regarding total hip and total knee arthroplasty.

Avascular necrosis of the trapezoid bone following carpometacarpal arthroplasty.

Science.gov (United States)

Kane, Patrick; Waryasz, Greg; Katarincic, Julie

2014-03-03

A 58-year-old female developed avascular necrosis of her trapezoid approximately 3 months after undergoing carpometacarpal arthroplasty. The patient was treated conservatively with immobilization and had complete resolution of her clinical symptoms during her year of follow-up. Additionally, radiographic examination showed complete restoration of the height of her trapezoid approximately 1 year after the index procedure. Avascular necrosis of the trapezoid is extremely rare with very few cases described in the literature. This is the first description of avascular necrosis following carpometacarpal arthroplasty.

The comparative study of lumbar disc disruption with MRI and CT discography

International Nuclear Information System (INIS)

Chen Xingcan; Liu Naifang; Li Xiaohong; Xu Wengen; Zou Qing; Yang Yonghong

2005-01-01

Objective: To compare MRI with CT discography (CTD) for diagnostic assessment of lumbar disc disruption. Methods: Paired comparative examination in 16 patients with chronic lower back pain without radicular pain and no disc herniation was conducted using CT or MRI. The standard of CTD classification and positive disc was formulated and the correlation between the induced lower back pain and dosage used in CTD was observed. Results: For a total of 21 discs in the 16 patients, CTD showed the disc as type 2 in 12 discs and type 5 in 1 disc with 13 positive discs, while MRI only showed the high-intensity zone of posterior annulus in 6 discs as the indirect sign of disc disruption and disc degeneration in 7 discs. Conclusion: CTD was the only method for showing the direct sign of disc disruption. The induced lower back pain was related with the type of disc disruption. MRI can show some of the indirect signs of disc disruption and CTD can show the direct sign of disc disruption. (authors)

Exoplanet recycling in massive white-dwarf debris discs

Science.gov (United States)

van Lieshout, R.; Kral, Q.; Charnoz, S.; Wyatt, M. C.; Shannon, A.

2018-05-01

Several tens of white dwarfs are known to host circumstellar discs of dusty debris, thought to arise from the tidal disruption of rocky bodies originating in the star's remnant planetary system. This paper investigates the evolution of such discs if they are very massive, as may be the case if their progenitor was a terrestrial planet, moon, or dwarf planet. Assuming the discs are physically thin and flat, like Saturn's rings, their evolution is governed by Poynting-Robertson drag or viscous spreading, where the disc's effective viscosity is due to self-gravity wakes. For discs with masses ≳ 1026 g, located in the outer parts of the tidal disruption zone, viscous spreading dominates the evolution, and mass is transported both in- and outwards. When outwards-spreading material flows beyond the Roche limit, it coagulates into new (minor) planets in a process analogous to the ongoing formation of moonlets at the outer edge of Saturn's rings. The newly formed bodies migrate outwards by exchanging angular momentum with the disc and coalesce into larger objects through mutual collisions. Eventually, the disc's Roche-limit overflow recycles tens of percent of the original disc mass; most ends up in a single large body near 2:1 mean-motion resonance with the disc's outer edge. Hence, the recycling of a tidally disrupted super-Earth, for example, could yield an Earth-mass planet on a ˜10-h orbit, located in the habitable zone for 2-to-10-Gyr-old white dwarfs. The recycling process also creates a population of smaller bodies just outside the Roche limit, which may explain the minor planets recently postulated to orbit WD 1145+017.

SIMULTANEOUS DISC HERNIATION IN PATIENTS WITH MULTIPLE SCLEROSIS

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Kalina V. Drenska

2013-04-01

Full Text Available Background: Multiple sclerosis (MS is a chronic autoimmune, inflammatory demyelinating disease of the central nervous system. Commonly, MS patients present with accompanying degenerative vertebral disc diseases. Simultaneous disc herniations situated in the cervical or lumbosacral spine can mimic the clinical symptoms of MS and worsen patients’ quality of life.Objective: to investigate the incidence rate and clinical impact of accompanying disc herniations in patients with MS.Material and methods: Our study covered 330 patients (220 females and 110 males, mean age 40.5±12.4 years with clinically definite MS, according to McDonald’s criteria. Comprehensive neurological examinations, EDSS (Expanded Disability Status Scale assessments, and MRI neuroimaging were carried out. Statistical data processing was performed by using the method of variation analysis.Results: Relapsing-remitting MS (RRMS was diagnosed in 280 patients while 50 patients presented with secondary progressive MS (SPMS. Disc herniation was found in 64 (19.4% of our patients. Cervical disc pathology was detected in 38 patients (11.5% of the cases and lumbosacral - in 26 (7.9% of the cases. EDSS scores ranged from 2.5 to 5.5. EDSS evaluation showed statistically significantly worse scores in MS patients with disc herniation comorbidity (p<0, 05.Conclusion: Our own data confirm the assumption that MS patients often present with accompanying degenerative disc pathology. We suggest that comorbidity of disc herniation and MS exert an additional unfavorable effect on patient’s disability and individual quality of life.

CT in diagnosis of recurrent vertebral disc hernias after preceding lumbar disc prolapse surgery

International Nuclear Information System (INIS)

Burval, S.; Nekula, J.; Vaverka, M.; Veliskova, J.

1992-01-01

20 patients with recurrent symptoms following operations for disc prolapse and resistant to treatment were studied by CT, using plain and enhanced images. The results have been analysed. In 10 patients a recurrence of disc prolapse was diagnosed, and this was confirmed surgically in 8 cases. In 2 patients there was epidural scarring. The findings indicate that differential diagnosis between scarring and recurring prolapse can by accurately made by this technique. (orig.) [de

LUMBOSACRAL TRANSITIONAL ANATOMY TYPES AND DISC DEGENERATIVE CHANGES

Directory of Open Access Journals (Sweden)

Chabukovska Radulovska Jasminka

2014-07-01

Full Text Available Background and purpose: The relationship between presence of lumbo sacral transitional vertebra (LSTV and disc degenerative changes is unclear. The aim of the study was to examine the relation between different types of LSTV and disc degenerative changes at the transitional and the adjacent cephalad segment. Material and methods: Sixty-three patients (mean age 51.48 ± 13.51 out of 200 adults with low back pain who performed MRI examination of the lumbo sacral spine, classified as positive for LSTV, were included in the study. Annular tears, disc degeneration according to Phirmann classification and disc herniations were evaluated and graded at transitional and adjacent cephalad level. Results: The severity of disc degeneration at the transitional level and the adjacent level correlated with the types of LSTV. Severe disc degenerative changes were most frequent in articulated connection LSTV types and incombined LSTV type at the transitional level and in osseus connection LSTV types at the adjacent cephalad level. These changes were more frequent in unilateral articulated connection LSTV subtype (64% vs 54%; and in unilateral osseus connection LSTV subtype (25% vs no patients at transitional level, and in bilateral osseus connection LSTV subtype (100% vs 50% at the level above. High prevalence of disc herniations was observed in articulated connection LSTV types as well as in unilateral osseus connection LSTV subtype at transitional and the adjacent cephalad level. At the transitional level higher prevalence of disc herniations was characteristic for unilateral articulated connection LSTV sub type (46%vs 41% and for unilateral osseus connection LSTV subtype (50% vs no patients. At the adjacent level higher prevalence of disc herniations was observed in bilateral articulated connection LSTV subtype (38% vs 27% and in bilateral osseus connection LSTV subtype (50% vs 25%. Conclusions: The compact osseus connection (osseus bridging vs articular

Lumbosacral transitional anatomy types and disc degenerative changes

Directory of Open Access Journals (Sweden)

Chabukovska-Radulovska Jasminka

2014-07-01

Full Text Available Background and purpose: The relationship between presence of lumbosacral transitional vertebra (LSTV and disc degenerative changes is unclear. The aim of the study was to examine the relation between different types of LSTV and disc degenerative changes at the transitional and the adjacent cephalad segment. Material and methods: Sixty-three patients (mean age 51.48 ± 13.51 out of200 adults with low back pain who performed MRI examination of the lumbosacral spine, classified as positive for LSTV, were included in the study. Annular tears, disc degeneration according to Phirmann classification and disc herniations were evaluated and graded at transitional and adjacent cephalad level. Results: The severity of disc degeneration at the transitional level and the adjacent level correlated with the types of LSTV. Severe disc degenerative changes were most frequent in articulated connection LSTV types and in combined LSTV type at the transitional level and in osseus connection LSTV types at the adjacent cephalad level. These changes were more frequent in unilateral articulated connection LSTV subtype (64% vs 54%; and in unilateral osseus connection LSTV subtype (25% vs no patients at transitional level, and in bilateral osseus connection LSTV subtype (100% vs 50% at the level above. High prevalence of disc herniations was observed in articulated connection LSTV types as well as in unilateral osseus connection LSTV subtype at transitional and the adjacent cephalad level. At the transitional level higher prevalence of disc herniations was characteristic for unilateral articulated connection LSTV subtype (46%vs 41% and for unilateral osseus connection LSTV subtype (50% vs no patients. At the adjacent level higher prevalence of disc herniations was observed in bilateral articulated connection LSTV subtype (38% vs 27% and in bilateral osseus connection LSTV subtype (50% vs 25%. Conclusions: The compact osseus connection (osseus bridging vs articular

Isolated patellofemoral arthroplasty reproduces natural patellofemoral joint kinematics when the patella is resurfaced.

Science.gov (United States)

Vandenneucker, Hilde; Labey, Luc; Vander Sloten, Jos; Desloovere, Kaat; Bellemans, Johan

2016-11-01

The objectives of this in vitro project were to compare the dynamic three-dimensional patellofemoral kinematics, contact forces, contact areas and contact pressures of a contemporary patellofemoral prosthetic implant with those of the native knee and to measure the influence of patellar resurfacing and patellar thickness. The hypothesis was that these designs are capable to reproduce the natural kinematics but result in higher contact pressures. Six fresh-frozen specimens were tested on a custom-made mechanical knee rig before and after prosthetic trochlear resurfacing, without and with patellar resurfacing in three different patellar thicknesses. Full three-dimensional kinematics were analysed during three different motor tasks, using infrared motion capture cameras and retroflective markers. Patellar contact characteristics were registered using a pressure measuring device. The patellofemoral kinematic behaviour of the patellofemoral arthroplasty was similar to that of the normal knee when the patella was resurfaced, showing only significant (p patellofemoral kinematics acceptable well when the patella was resurfaced. From a kinematic point of view, patellar resurfacing may be advisable. However, the substantially elevated patellar contact pressures remain a point of concern in the decision whether or not to resurface the patella. This study therefore not only adds a new point in the discussion whether or not to resurface the patella, but also supports the claimed advantage that a patellofemoral arthroplasty is capable to reproduce the natural knee kinematics.

The evolution of stellar exponential discs

NARCIS (Netherlands)

Ferguson, AMN; Clarke, CJ

2001-01-01

Models of disc galaxies which invoke viscosity-driven radial flows have long been known to provide a natural explanation for the origin of stellar exponential discs, under the assumption that the star formation and viscous time-scales are comparable. We present models which invoke simultaneous star

Cost Utility Analysis of the Cervical Artificial Disc vs Fusion for the Treatment of 2-Level Symptomatic Degenerative Disc Disease: 5-Year Follow-up.

Science.gov (United States)

Ament, Jared D; Yang, Zhuo; Nunley, Pierce; Stone, Marcus B; Lee, Darrin; Kim, Kee D

2016-07-01

The cervical total disc replacement (cTDR) was developed to treat cervical degenerative disc disease while preserving motion. Cost-effectiveness of this intervention was established by looking at 2-year follow-up, and this update reevaluates our analysis over 5 years. Data were derived from a randomized trial of 330 patients. Data from the 12-Item Short Form Health Survey were transformed into utilities by using the SF-6D algorithm. Costs were calculated by extracting diagnosis-related group codes and then applying 2014 Medicare reimbursement rates. A Markov model evaluated quality-adjusted life years (QALYs) for both treatment groups. Univariate and multivariate sensitivity analyses were conducted to test the stability of the model. The model adopted both societal and health system perspectives and applied a 3% annual discount rate. The cTDR costs $1687 more than anterior cervical discectomy and fusion (ACDF) over 5 years. In contrast, cTDR had $34 377 less productivity loss compared with ACDF. There was a significant difference in the return-to-work rate (81.6% compared with 65.4% for cTDR and ACDF, respectively; P = .029). From a societal perspective, the incremental cost-effective ratio (ICER) for cTDR was -$165 103 per QALY. From a health system perspective, the ICER for cTDR was $8518 per QALY. In the sensitivity analysis, the ICER for cTDR remained below the US willingness-to-pay threshold of $50 000 per QALY in all scenarios (-$225 816 per QALY to $22 071 per QALY). This study is the first to report the comparative cost-effectiveness of cTDR vs ACDF for 2-level degenerative disc disease at 5 years. The authors conclude that, because of the negative ICER, cTDR is the dominant modality. ACDF, anterior cervical discectomy and fusionAWP, average wholesale priceCE, cost-effectivenessCEA, cost-effectiveness analysisCPT, Current Procedural TerminologycTDR, cervical total disc replacementCUA, cost-utility analysisDDD, degenerative disc disease

Grain size segregation in debris discs

Science.gov (United States)

Thebault, P.; Kral, Q.; Augereau, J.-C.

2014-01-01

Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ∝ s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ≤ -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED

Prevention of venous thromboembolic disease after total hip and knee arthroplasty.

Science.gov (United States)

Lieberman, Jay R; Hsu, Wellington K

2005-09-01

Patients undergoing total hip and knee arthroplasty are at increased risk for the development of venous thromboembolic disease, and there is general agreement that these patients require prophylaxis. The selection of a prophylactic agent involves a balance between efficacy and safety and often needs to be individualized for specific patients and institutions. Despite extensive research, the ideal agent for prophylaxis against deep venous thrombosis has not been identified. The results of randomized trials indicate that low-molecular-weight heparin, warfarin, and fondaparinux are the most effective prophylactic agents after total hip arthroplasty and that low-molecular-weight heparin, warfarin, fondaparinux, and pneumatic compression boots are the most effective agents after total knee arthroplasty. The duration of prophylaxis against deep venous thrombosis after total hip and knee arthroplasty remains controversial. Prophylaxis should be continued beyond hospital discharge. In the future, the determination of the duration of prophylaxis will be based on the risk stratification of individual patients. The practice of discharging patients from the hospital without prophylaxis, even when the decision is based on negative results of procedures that screen for the presence of deep venous thrombosis, is not cost-effective.

Trabecular metal acetabular components in primary total hip arthroplasty

DEFF Research Database (Denmark)

Laaksonen, Inari; Lorimer, Michelle; Gromov, Kirill

2018-01-01

Background and purpose - Trabecular metal (TM) cups have demonstrated favorable results in acetabular revision and their use in primary total hip arthroplasty (THA) is increasing. Some evidence show that TM cups might decrease periprosthetic infection (PPI) incidence. We compared the survivorship...... of TM cups with that of other uncemented cups in primary THA, and evaluated whether the use of TM cups is associated with a lower risk of PPI. Patients and methods - 10,113 primary THAs with TM cup and 85,596 THAs with other uncemented cups from 2 high-quality national arthroplasty registries were...

The role of pain for early rehabilitation in fast track total knee arthroplasty

DEFF Research Database (Denmark)

Holm, Bente; Kristensen, Morten Tange; Myhrmann, Lis

2010-01-01

To investigate the relationship between early functional mobility and pain intensity in a fast track program after total knee arthroplasty (TKA).......To investigate the relationship between early functional mobility and pain intensity in a fast track program after total knee arthroplasty (TKA)....

Biomimetic hydrogels for biosensor implant biocompatibility: electrochemical characterization using micro-disc electrode arrays (MDEAs).

Science.gov (United States)

Justin, Gusphyl; Finley, Stephen; Abdur Rahman, Abdur Rub; Guiseppi-Elie, Anthony

2009-02-01

Our interest is in the development of engineered microdevices for continuous remote monitoring of intramuscular lactate, glucose, pH and temperature during post-traumatic hemorrhaging. Two important design considerations in the development of such devices for in vivo diagnostics are discussed; the utility of micro-disc electrode arrays (MDEAs) for electrochemical biosensing and the application of biomimetic, bioactive poly(HEMA)-based hydrogel composites for implant biocompatibility. A poly(HEMA)-based hydrogel membrane containing polyethylene glycol (PEG) was UV cross-linked with tetraethyleneglycol diacrylate following application to MDEAs (50 mum discs) and to 250 mum diameter gold electrodes within 8-well culture ware. Cyclic voltammetry (CV) of the MDEAs revealed a reduction in the apparent diffusion coefficient of ferrocenemonocarboxylic acid (FcCO(2)H), from 6.68 x 10(-5) to 6.74 x 10(-6) cm(2)/s for the uncoated and 6 mum thick hydrogel coated devices, respectively. Single frequency (4 kHz) temporal impedance measurements of the hydrogels in the 8-well culture ware showed a reversible 5% change in the absolute impedance of the hydrogels when exposed to a pH change between 6.1 to 7.2 and a 20% drop between pH 6.1 and 8.8.

Time Localisation of Surface Defects on Optical Discs

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Wickerhauser, M.V.

Many have experienced problems with their Compact Disc player when a disc with a scratch or a finger print is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localisation...

Time Localisation of Surface Defects on Optical Discs

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Wickerhauser, M.V.

2004-01-01

Many have experienced problems with their Compact Disc Player when a disc with a scratch or a fingerprint is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localization...

Intradiscal injection of simvastatin results in radiologic, histologic, and genetic evidence of disc regeneration in a rat model of degenerative disc disease

Science.gov (United States)

Than, Khoi D.; Rahman, Shayan U.; Wang, Lin; Khan, Adam; Kyere, Kwaku A.; Than, Tracey T.; Miyata, Yoshinari; Park, Yoon-Shin; La Marca, Frank; Kim, Hyungjin M.; Zhang, Huina; Park, Paul; Lin, Chia-Ying

2014-01-01

BACKGROUND CONTEXT A large percentage of back pain can be attributed to degeneration of the intervertebral disc (IVD). Bone morphogenetic protein-2 (BMP-2) is known to play an important role in chondrogenesis of the IVD. Simvastatin is known to up-regulate expression of BMP-2. Thus, we hypothesized that intradiscal injection of simvastatin in a rat model of degenerative disc disease (DDD) would result in retardation of DDD. PURPOSE To develop a novel conservative treatment for DDD and related discogenic back pain. STUDY DESIGN/SETTING Laboratory investigation. METHODS Disc injury was induced in 272 rats via 21-gauge needle puncture. After 6 weeks, injured discs were treated with simvastatin in a saline or hydrogel carrier. Rats were sacrificed at predetermined time points. Outcome measures assessed were radiologic, histologic, and genetic. Radiologically, the MRI index (number of pixels multiplied by corresponding image densities) was determined. Histologically, disc spaces were read by 3 blinded scorers employing a previously described histological grading scale. Genetically, nuclei pulposi were harvested and polymerase chain reaction was run to determine relative levels of aggrecan, collagen type II, and BMP-2 gene expression. This project was supported by Grant No. R01 AR056649 from NIAMS/NIH. There are no other financial conflicts of interest to report. RESULTS Radiologically, discs treated with 5 mg/mL simvastatin in hydrogel or saline demonstrated MRI indices that were normal through 8 weeks post-treatment, although this was more sustained when delivered in hydrogel. Histologically, discs treated with 5 mg/mL simvastatin in hydrogel demonstrated improved grades in comparison to discs treated at higher doses. Genetically, discs treated with 5 mg/mL of simvastatin in hydrogel demonstrated higher gene expression of aggrecan and collagen type II than control. CONCLUSIONS Degenerate discs treated with 5 mg/mL simvastatin in a hydrogel carrier demonstrated

New Brown Dwarf Discs in Upper Scorpius Observed with WISE

Science.gov (United States)

Dawson, P.; Scholz, A.; Ray, T. P.; Natta, A.; Marsh, K. A.; Padgett, D.; Ressler, M. E.

2013-01-01

We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour magnitude and colour colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 microns and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars.We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5 10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

Bilateral custom-fit total knee arthroplasty in a patient with poliomyelitis.

Science.gov (United States)

Tardy, Nicolas; Chambat, Pierre; Murphy, Colin G; Fayard, Jean-Marie

2014-09-01

In limbs affected by poliomyelitis, total knee arthroplasty results in satisfactory pain relief. However, the risk of failure is high, especially if the preoperative quadriceps power is low. Therefore, treating osteoarthritis in the current patient represented a challenging procedure. A 66-year-old man presented with tricompartmental osteoarthritis of both knees, with valgus deformity of 14° on the left knee and 11° on the right knee. He walked with a bilateral knee recurvatum of 30° and a grade 1 quadriceps power. The authors treated both knees with cemented custom-fit hinged total knee arthroplasty with 30° of recurvatum in the tibial keel. Clinical scores showed good results 1 year postoperatively, especially on the subjective data of quality of life and function. At follow-up, radiographs showed good total knee arthroplasty positioning on the right side and a small mechanical loosening at the end of the tibial keel on the left side. Only 5 studies (Patterson and Insall; Moran; Giori and Lewallen; Jordan et al; and Tigani et al) have reported total knee arthroplasty results in patients with poliomyelitis. This study reports an original case of bilateral custom-fit hinged total knee arthroplasty in a patient with poliomyelitis. To the authors' knowledge, this is the first report of this type of procedure in the literature. The key point is the degree of recurvatum that is needed to allow walking, avoiding excessive constraints on the implants that can lead to early mechanical failure. Copyright 2014, SLACK Incorporated.

MRI findings of traumatic cervical disc herniation

International Nuclear Information System (INIS)

Tanaka, Hisato; Kasahara, Takaki; Akiyama, Nanae

2011-01-01

In general practice, disc hernia is increasingly being questioned about its relation with traffic injuries. In this study, we examined the image findings of cervical disc herniation for findings indicative of traumatic hernia. In 2008, we examined 35 cases of cervical disc herniation at our hospital by MRI. The patients were divided into two groups; patients with trauma history (19 cases) and those without (16 cases), and their images were compared. Disc herniation in the trauma group showed high intensity at T2, with some of the patients in this group also indicating continuous high intensity of the internal and herniated discs. Traumatic force was found to cause swelling under the laryngeal soft tissue. Cases with further flexion injury showed interspinous ligament hemorrhage. These findings strongly suggest the involvement of injury. But given that some younger patients in the non-trauma group also show high intensity at T2*, attention must be paid not to confuse swelling below the larynx with inflammation of the longus colli muscle. (author)

Physical Limitations to Tissue Engineering of Intervertabral Disc Cells

OpenAIRE

Kobayashi, Shigeru; Baba, Hisatoshi; Takeno, Kenichi; Miyazaki, Tsuyoshi; Meir, Adam; Urban, Jill

2010-01-01

There is increasing interest in the using biological methods to repair degenerate discs. Biological repair depends on the disc maintaining a population of viable and active cells. Adequate nutrition of the disc influences the outcome of such therapies and, hence, must be considered to be a crucial parameter. Therefore, it is very important to maintain an appropriate physicochemical environment to achieve successful disc repair by biological methods and tissue engineering procedures.

Recurrent hemarthrosis after total knee arthroplasty

NARCIS (Netherlands)

Rukavina, A.; Kerkhoffs, G.M.M.J.; Schneider, P.; Kuster, M.S.

2010-01-01

This report describes a case of spontaneous recurrent hemarthrosis of the knee that presented 4 weeks after total knee arthroplasty. Femoral arteriography showed a false aneurysm of a branch of the inferior lateral geniculate artery. Therapeutic embolization of the arterial branch was performed

Nonlinear dynamics of the human lumbar intervertebral disc.

Science.gov (United States)

Marini, Giacomo; Huber, Gerd; Püschel, Klaus; Ferguson, Stephen J

2015-02-05

Systems with a quasi-static response similar to the axial response of the intervertebral disc (i.e. progressive stiffening) often present complex dynamics, characterized by peculiar nonlinearities in the frequency response. However, such characteristics have not been reported for the dynamic response of the disc. The accurate understanding of disc dynamics is essential to investigate the unclear correlation between whole body vibration and low back pain. The present study investigated the dynamic response of the disc, including its potential nonlinear response, over a range of loading conditions. Human lumbar discs were tested by applying a static preload to the top and a sinusoidal displacement at the bottom of the disc. The frequency of the stimuli was set to increase linearly from a low frequency to a high frequency limit and back down. In general, the response showed nonlinear and asymmetric characteristics. For each test, the disc had different response in the frequency-increasing compared to the frequency-decreasing sweep. In particular, the system presented abrupt changes of the oscillation amplitude at specific frequencies, which differed between the two sweeps. This behaviour indicates that the system oscillation has a different equilibrium condition depending on the path followed by the stimuli. Preload and amplitude of the oscillation directly influenced the disc response by changing the nonlinear dynamics and frequency of the jump-phenomenon. These results show that the characterization of the dynamic response of physiological systems should be readdressed to determine potential nonlinearities. Their direct effect on the system function should be further investigated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prevalence of disc cupping in non-glaucomatous eyes

Directory of Open Access Journals (Sweden)

José Pablo Chiappe

2015-02-01

Full Text Available This study assessed optic disc size and cupping, using a commercially available ophthalmoscope, in order to show norms of these values for clinical practice. Subjects were office-workers referred from their respective workplaces for a routine medical examination, which included eye examination. The optic disc size was classified as small, medium or large, for having a diameter 1.5 times (respectively the diameter of the ophthalmoscope's selected light spot on the posterior pole. The cupping was classified as the ratio of the vertical cupping diameter and the vertical disc diameter on a relative decimal scale from 0.0 to 1.0.This study included 184 subjects with a mean age of 40.5 ± 9.5 years; 149 (81% were males. Their mean ocular pressure was 12.4 ± 1.5 mmHg (range 10-17 mmHg. There was a high correlation between optic disc sizes and cupping in the right and left eyes (Pearson Correlation r = 0.866, p < 0.001; therefore, for simplicity only the data for right eyes are presented. According to our definition, the optic discs in these eyes comprised 27 (14.7% small, 141 (76.6% medium and 16 (8.7% large. The small optic discs were rarely cupped, and the large optic discs were always cupped. Optic disc cupping greater than 0.7 was rarely found and should be suspect of glaucoma. Clinical doctors should be aware of this and refer those subjects with abnormal cupping to the specialist.

Efficacy and safety of Mobi-C cervical artificial disc versus anterior discectomy and fusion in patients with symptomatic degenerative disc disease: A meta-analysis.

Science.gov (United States)

Lu, Hui; Peng, Lihua

2017-12-01

Total disc replacement (TDR) using Mobi-C cervical artificial disc might be promising to treat symptomatic degenerative disc disease. However, the results remained controversial. We conducted a systematic review and meta-analysis to compare the efficacy and safety of Mobi-C cervical artificial disc and anterior cervical discectomy and fusion (ACDF) in patients with symptomatic degenerative disc disease. PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCTs) assessing the effect of Mobi-C versus ACDF on the treatment of symptomatic degenerative disc disease were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were neck disability index (NDI) score, patient satisfaction, and subsequent surgical intervention. Meta-analysis was performed using the random-effect model. Four RCTs were included in the meta-analysis. Overall, compared with ACDF surgery for symptomatic degenerative disc disease, TDR using Mobi-C was associated with a significantly increased NDI score (Std. mean difference = 0.32; 95% CI = 0.10-0.53; P = .004), patient satisfaction (odds risk [OR] = 2.75; 95% confidence interval [CI] = 1.43-5.27; P = .002), and reduced subsequent surgical intervention (OR = 0.20; 95% CI = 0.11-0.37; P degenerative disc disease, TDR using Mobi-C cervical artificial disc resulted in a significantly improved NDI score, patient satisfaction, and reduced subsequent surgical intervention. There was no significant difference of neurological deterioration, radiographic success, and overall success between TDR using Mobi-C cervical artificial disc versus ACDF surgery. TDR using Mobi-C cervical artificial disc should be recommended for the treatment of symptomatic degenerative disc disease.

Optic Disc Change during Childhood Myopic Shift: Comparison between Eyes with an Enlarged Cup-To-Disc Ratio and Childhood Glaucoma Compared to Normal Myopic Eyes.

Directory of Open Access Journals (Sweden)

Hae-Young Lopilly Park

Full Text Available Progressive disc tilting and the development or enlargement of peripapillary atrophy (PPA are observed during a myopic shift in children. This could be related to the changes around the optic nerve head during eyeball elongation. If the biomechanical properties at or around the optic nerve head are changed after exposure to elevated intraocular pressure (IOP in glaucoma eyes, different response of the disc tilting and PPA changes could take place during eyeball elongation by myopic shift. On the basis of this background, the aim of this study was to compare the morphological changes in the optic disc induced by a myopic shift during childhood between normal control eyes, eyes from disc suspects with an enlarged cup-to-disc ratio (CDR, and eyes with childhood glaucoma.Total of 82 eyes from 82 subjects younger than 14 years of age were included in the study. Serial disc photographs were classified into one of two groups: eyes with an optic nerve head (ONH or peripapillary atrophy (PPA change or without an ONH/PPA change. Using ImageJ software, the outlines of the optic disc and PPA were plotted, and the vertical disc diameter (VDD, horizontal disc diameter (HDD, and maximum PPA width (PPW were measured. The changes in the ratios of these parameters and the relationships between the degree of myopic shift or the ONH/PPA change were analyzed.Twenty-five eyes with normal optic disc appearance, 36 eyes with enlarged cup-to-disc ratio, and 21 eyes of glaucoma patients were analyzed. The initial intraocular pressure (IOP at diagnosis was significantly different among the groups (P<0.001. The degree of myopic shift during follow-up period was not significantly different among the groups (P=0.612. However, the changes in the HDD/VDD and PPW/VDD ratios were significantly greater in the disc suspect group and significantly smaller in the glaucoma group. Among the 42 eyes with an ONH/PPA change, 16 (38.1% were from the normal control group, 24 (57.1% were

Total knee arthroplasty

DEFF Research Database (Denmark)

Schrøder, Henrik M.; Petersen, Michael M.

2016-01-01

Total knee arthroplasty (TKA) is a successful treatment of the osteoarthritic knee, which has increased dramatically over the last 30 years. The indication is a painful osteoarthritic knee with relevant radiographic findings and failure of conservative measures like painkillers and exercise...... surgeon seems to positively influence the rate of surgical complications and implant survival. The painful TKA knee should be thoroughly evaluated, but not revised except if a relevant indication can be established. The most frequent indications for revision are: aseptic loosening, instability, infection...

Apparent quasar disc sizes in the "bird's nest" paradigm

Science.gov (United States)

Abolmasov, P.

2017-04-01

Context. Quasar microlensing effects make it possible to measure the accretion disc sizes around distant supermassive black holes that are still well beyond the spatial resolution of contemporary instrumentation. The sizes measured with this technique appear inconsistent with the standard accretion disc model. Not only are the measured accretion disc sizes larger, but their dependence on wavelength is in most cases completely different from the predictions of the standard model. Aims: We suggest that these discrepancies may arise not from non-standard accretion disc structure or systematic errors, as it was proposed before, but rather from scattering and reprocession of the radiation of the disc. In particular, the matter falling from the gaseous torus and presumably feeding the accretion disc may at certain distances become ionized and produce an extended halo that is free from colour gradients. Methods: A simple analytical model is proposed assuming that a geometrically thick translucent inflow acts as a scattering mirror changing the apparent spatial properties of the disc. This inflow may be also identified with the broad line region or its inner parts. Results: Such a model is able to explain the basic properties of the apparent disc sizes, primarily their large values and their shallow dependence on wavelength. The only condition required is to scatter a significant portion of the luminosity of the disc. This can easily be fulfilled if the scattering inflow has a large geometrical thickness and clumpy structure.

The diagnosis of internal disc disruption with CT discography

International Nuclear Information System (INIS)

Liu Miao; Chen Xingcan; Li Xiaohong; Pan Yongqin

2008-01-01

Objective: To study the value of diagnosis for internal disc disruption (IDD)with CT discography(CTD). Methods: 42 discs of 32 patients showing no disc herniation on CT or MRI, but suffering from chronic low back pain, were undertaken CTD to work out the types of CTD with correlation between contrast medium dosages and the induction of pain. Results: CTD demonstrated 4 types of IDD which was individually correlated with the contrast dosages and induced pain; furthermore the dosages for positive and negative disc cases showed significant differece (P<0.01). Conclusions: CTD can show the direct sign of internal disc disruption, providing more information than conventional discography. (authors)

POSTERIOR APPROACH FOR HIP ARTHROPLASTY: A SINGLE ...

African Journals Online (AJOL)

postulated advantages and disadvantages. Objective: Presentation of a case series of primary and revision arthroplasty utilizing the posterior approach. ... Centre over a period of one year were queried and data extracted and recorded.

Fission gas release behaviour of a 103 GWd/t{sub HM} fuel disc during a 1200 °C annealing test

Energy Technology Data Exchange (ETDEWEB)

Noirot, J., E-mail: jean.noirot@cea.fr [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Pontillon, Y. [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Yagnik, S. [EPRI, P.O. Box 10412, Palo Alto, CA 94303-0813 (United States); Turnbull, J.A. [Independent Consultant (United Kingdom); Tverberg, T. [IFE, P.O. Box 173, NO-1751 Halden (Norway)

2014-03-15

Within the Nuclear Fuel Industry Research (NFIR) program, several fuel variants, in the form of thin circular discs, were irradiated in the Halden Boiling Water Reactor (HBWR) to a range of burn-ups ∼100 GWd/t{sub HM}. The design of the assembly was similar to that used in other HBWR programs: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature gradients within the fuel discs. One such rod contained standard grain UO{sub 2} discs (3D grain size = 18 μm) reaching a burn-up of 103 GWd/t{sub HM}. After the irradiation, the gas release upon rod puncturing was measured to be 2.9%. Detailed characterizations of one of these irradiated UO{sub 2} discs, using electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS), were performed in a CEA Cadarache hot laboratory. Examination revealed the high burn-up structure (HBS) formation throughout the whole of the disc, also the fission gas distribution within this HBS, with a very high proportion of the gas in the HBS bubbles. A sibling disc was submitted to a temperature transient up to 1200 °C in the out-of-pile (OOP) annealing test device “Merarg” at a relatively low temperature ramp rate (0.2 °C/s). In addition to the total gas release during this annealing test, the release peaks throughout the temperature range were monitored. The fuel was then characterized with the same microanalysis techniques as before the annealing test to investigate the effects of this test on the microstructure of the fuel and on the fission gases. It provided valuable insights into fission gas localization and the release behaviour in UO{sub 2} fuel with high burn-up structure (HBS)

Combining Electro-Osmotic Flow and FTA® Paper for DNA Analysis on Microfluidic Devices

Directory of Open Access Journals (Sweden)

Ryan Wimbles

2016-07-01

Full Text Available FTA® paper can be used to protect a variety of biological samples prior to analysis, facilitating ease-of-transport to laboratories or long-term archive storage. The use of FTA® paper as a solid phase eradicates the need to elute the nucleic acids from the matrix prior to DNA amplification, enabling both DNA purification and polymerase chain reaction (PCR-based DNA amplification to be performed in a single chamber on the microfluidic device. A disc of FTA® paper, containing a biological sample, was placed within the microfluidic device on top of wax-encapsulated DNA amplification reagents. The disc containing the biological sample was then cleaned up using Tris-EDTA (TE buffer, which was passed over the disc, via electro-osmotic flow, in order to remove any potential inhibitors of downstream processes. DNA amplification was successfully performed (from buccal cells, whole blood and semen using a Peltier thermal cycling system, whereupon the stored PCR reagents were released during the initial denaturing step due to the wax barrier melting between the FTA® disc and PCR reagents. Such a system offers advantages in terms of a simple sample introduction interface and the ability to process archived samples in an integrated microfluidic environment with minimal risk of contamination.

Percutaneous treatment of cervical and lumbar herniated disc

Energy Technology Data Exchange (ETDEWEB)

Kelekis, A., E-mail: akelekis@med.uoa.gr; Filippiadis, D.K., E-mail: dfilippiadis@yahoo.gr

2015-05-15

Therapeutic armamentarium for symptomatic intervertebral disc herniation includes conservative therapy, epidural infiltrations (interlaminar or trans-foraminal), percutaneous therapeutic techniques and surgical options. Percutaneous, therapeutic techniques are imaging-guided, minimally invasive treatments for intervertebral disc herniation which can be performed as outpatient procedures. They can be classified in 4 main categories: mechanical, thermal, chemical decompression and biomaterials implantation. Strict sterility measures are a prerequisite and should include extensive local sterility and antibiotic prophylaxis. Indications include the presence of a symptomatic, small to medium sized contained intervertebral disc herniation non-responding to a 4–6 weeks course of conservative therapy. Contraindications include sequestration, infection, segmental instability (spondylolisthesis), uncorrected coagulopathy or a patient unwilling to provide informed consent. Decompression techniques are feasible and reproducible, efficient (75–94% success rate) and safe (>0.5% mean complications rate) therapies for the treatment of symptomatic intervertebral disc herniation. Percutaneous, imaging guided, intervertebral disc therapeutic techniques can be proposed either as an initial treatment or as an attractive alternative prior to surgery for the therapy of symptomatic herniation in both cervical and lumbar spine. This article will describe the mechanism of action for different therapeutic techniques applied to intervertebral discs of cervical and lumbar spine, summarize the data concerning safety and effectiveness of these treatments, and provide a rational approach for the therapy of symptomatic intervertebral disc herniation in cervical and lumbar spine.

Percutaneous treatment of cervical and lumbar herniated disc

International Nuclear Information System (INIS)

Kelekis, A.; Filippiadis, D.K.

2015-01-01

Therapeutic armamentarium for symptomatic intervertebral disc herniation includes conservative therapy, epidural infiltrations (interlaminar or trans-foraminal), percutaneous therapeutic techniques and surgical options. Percutaneous, therapeutic techniques are imaging-guided, minimally invasive treatments for intervertebral disc herniation which can be performed as outpatient procedures. They can be classified in 4 main categories: mechanical, thermal, chemical decompression and biomaterials implantation. Strict sterility measures are a prerequisite and should include extensive local sterility and antibiotic prophylaxis. Indications include the presence of a symptomatic, small to medium sized contained intervertebral disc herniation non-responding to a 4–6 weeks course of conservative therapy. Contraindications include sequestration, infection, segmental instability (spondylolisthesis), uncorrected coagulopathy or a patient unwilling to provide informed consent. Decompression techniques are feasible and reproducible, efficient (75–94% success rate) and safe (>0.5% mean complications rate) therapies for the treatment of symptomatic intervertebral disc herniation. Percutaneous, imaging guided, intervertebral disc therapeutic techniques can be proposed either as an initial treatment or as an attractive alternative prior to surgery for the therapy of symptomatic herniation in both cervical and lumbar spine. This article will describe the mechanism of action for different therapeutic techniques applied to intervertebral discs of cervical and lumbar spine, summarize the data concerning safety and effectiveness of these treatments, and provide a rational approach for the therapy of symptomatic intervertebral disc herniation in cervical and lumbar spine

Thermal analysis on motorcycle disc brake geometry

Science.gov (United States)

W. M. Zurin W., S.; Talib, R. J.; Ismail, N. I.

2017-08-01

Braking is a phase of slowing and stop the movement of motorcycle. During braking, the frictional heat was generated and the energy was ideally should be faster dissipated to surrounding to prevent the built up of the excessive temperature which may lead to brake fluid vaporization, thermoelastic deformation at the contact surface, material degradation and failure. In this paper, solid and ventilated type of motorcycle disc brake are being analyse using Computational Fluid Dynamic (CFD) software. The main focus of the analysis is the thermal behaviour during braking for solid and ventilated disc brake. A comparison between both geometries is being discussed to determine the better braking performance in term of temperature distribution. It is found that ventilated disc brake is having better braking performance in terms of heat transfer compare to solid disc.

Difference in clinical outcome between total shoulder arthroplasty and reverse shoulder arthroplasty used in hemiarthroplasty revision surgery

NARCIS (Netherlands)

Hartel, B.P.; Alta, T.D.; Sewnath, M.E.; Willems, W.J.H.

2015-01-01

INTRODUCTION: The increase of shoulder replacements will lead to a higher revision rate of shoulder arthroplasties. The aim of this study is to evaluate the clinical results of revision surgery performed in our hospital, distinguish the differences in clinical outcome according to revision

Positional and morphologic changes of the temporomandibular joint disc using magnetic resonance imaging

International Nuclear Information System (INIS)

Ahn, Hyoun Suk; Cho, Su Beom; Koh, Kwang Joon

2001-01-01

To evaluate displacement and morphologic changes of the temporomandibular joint (TMJ) disc in patient with internal derangement using magnetic resonance imaging (MRI). One hundred and forty five MR images of TMJs in 73 patients were evaluated. Positional and morphologic changes of the TMJ disc were assessed. Lateral or medial disc displacement was also evaluated on cornal images. Among 63 discs with anterior disc displacement, 37 discs were assessed as a biconcave disc and 21 as a deformed disc. Rotational disc displacement was observed in 35 disc. Anteromedial disc displacement was observed in 29 discs, and anterolateral direction in 6 discs. Among 35 rotational displacement, 5 biconcave discs and 21 deformed discs were observed. Rotational and sideways displacement of TMJ discs were found to be common and an important aspect of internal derangement. This study also suggests that sagittal and coronal images of the TMJ have complementary abilities for an assessment of joint abnormality

Adjacent level effects of bi level disc replacement, bi level fusion and disc replacement plus fusion in cervical spine--a finite element based study.

Science.gov (United States)

Faizan, Ahmad; Goel, Vijay K; Biyani, Ashok; Garfin, Steven R; Bono, Christopher M

2012-03-01

Studies delineating the adjacent level effect of single level disc replacement systems have been reported in literature. The aim of this study was to compare the adjacent level biomechanics of bi-level disc replacement, bi-level fusion and a construct having adjoining level disc replacement and fusion system. In total, biomechanics of four models- intact, bi level disc replacement, bi level fusion and fusion plus disc replacement at adjoining levels- was studied to gain insight into the effects of various instrumentation systems on cranial and caudal adjacent levels using finite element analysis (73.6N+varying moment). The bi-level fusion models are more than twice as stiff as compared to the intact model during flexion-extension, lateral bending and axial rotation. Bi-level disc replacement model required moments lower than intact model (1.5Nm). Fusion plus disc replacement model required moment 10-25% more than intact model, except in extension. Adjacent level motions, facet loads and endplate stresses increased substantially in the bi-level fusion model. On the other hand, adjacent level motions, facet loads and endplate stresses were similar to intact for the bi-level disc replacement model. For the fusion plus disc replacement model, adjacent level motions, facet loads and endplate stresses were closer to intact model rather than the bi-level fusion model, except in extension. Based on our finite element analysis, fusion plus disc replacement procedure has less severe biomechanical effects on adjacent levels when compared to bi-level fusion procedure. Bi-level disc replacement procedure did not have any adverse mechanical effects on adjacent levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

The 22-Modifier in Reimbursement for Orthopedic Procedures: Hip Arthroplasty and Obesity Are Worth the Effort.

Science.gov (United States)

Smith, Eric L; Tybor, David J; Daniell, Hayley D; Naccarato, Laura A; Pevear, Mary E; Cassidy, Charles

2018-02-21

Orthopedic surgeons utilize the 22-modifier when billing for complex procedures under the American Medical Association's Current Procedural Terminology (CPT) for reasons such as excessive blood loss, anatomic abnormality, and morbid obesity, cases that would ideally be reimbursed at a higher rate to compensate for additional physician work and time. We investigated how the 22-modifier affects physician reimbursement in knee and hip arthroplasty. We queried hospital billing data from 2009 to 2016, identifying all cases performed at our urban tertiary care orthopedic center for knee arthroplasty (CPT codes 27438, 27447, 27487, and 27488) and hip arthroplasty (CPT codes 27130, 27132, 27134, 27236). We extracted patient insurance status and reimbursement data to compare the average reimbursement between cases with and without the 22-modifier. We analyzed data from 2605 procedures performed by 10 providers. There were 136 cases with 22-modifiers. For knee arthroplasty (n = 1323), the 22-modifier did not significantly increase reimbursement after adjusting for insurer, provider, and fiscal year (4.2% dollars higher on average, P = .159). For hip arthroplasty (n = 1282), cases with a 22-modifier had significantly higher reimbursement than those without the 22-modifier (6.2% dollars more, P = .049). For hip arthroplasty cases with a 22-modifier, those noting morbid obesity were reimbursed 29% higher than those cases with other etiology. The effect of the 22-modifier on reimbursement amount is differential between knee and hip arthroplasty. Hip arthroplasty procedures coded as 22-modifier are reimbursed more than those without the 22-modifier. Providers should consider these potential returns when considering submitting a 22-modifier. Copyright © 2018 Elsevier Inc. All rights reserved.

Knee arthroplasty: are patients' expectations fulfilled?

DEFF Research Database (Denmark)

Nilsdotter, Anna K; Toksvig-Larsen, Sören; Roos, Ewa

2009-01-01

to pain and physical function after knee arthroplasty. PATIENTS AND METHODS: 102 patients (39 men) with knee osteoarthritis and who were assigned for TKR (mean age 71 (51-86) years) were investigated with KOOS, SF-36, and additional questions concerning physical activity level, expectations, satisfaction...

Isolated Optic Disc Tuberculosis

Science.gov (United States)

Mansour, Ahmad M.; Tabbara, Khalid F.; Tabbarah, Zuhair

2015-01-01

We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation. PMID:26483675

Isolated Optic Disc Tuberculosis

Directory of Open Access Journals (Sweden)

Ahmad M. Mansour

2015-09-01

Full Text Available We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation.

Comparison among perfect-C®, zero-P®, and plates with a cage in single-level cervical degenerative disc disease.

Science.gov (United States)

Noh, Sung Hyun; Zhang, Ho Yeol

2018-01-25

We intended to analyze the efficacy of a new integrated cage and plate device called Perfect-C for anterior cervical discectomy and fusion (ACDF) to cure single-level cervical degenerative disc disease. We enrolled 148 patients who were subjected to single-level ACDF with one of the following three surgical devices: a Perfect-C implant (41 patients), a Zero-P implant (36 patients), or a titanium plate with a polyetheretherketone (PEEK) cage (71 patients). We conducted a retrospective study to compare the clinical and radiological results among the three groups. The length of the operation, intraoperative blood loss, and duration of hospitalization were significantly lower in the Perfect-C group than in the Zero-P and plate-with-cage groups (P Zero-P groups but was noted in 21 cases (30%) in the plate-with-cage group. The cephalad and caudal plate-to-disc distance (PDD) and the cephalad and caudal PDD/anterior body height (ABH) were significantly greater in the Perfect-C and Zero-P groups than in the plate-with-cage group (P Zero-P group, and in 15 cases (21%) in the plate-with-cage group. Fusion occurred in 37 cases (90%) in the Perfect-C group, in 31 cases (86%) in the Zero-P group, and in 68 cases (95%) in the plate-with-cage group. The Perfect-C, Zero-P, and plate-with-cage devices are effective for treating single-level cervical degenerative disc disease. However, the Perfect-C implant has many advantages over both the Zero-P implant and conventional plate-cage treatments. The Perfect-C implant was associated with shorter operation times and hospitalization durations, less blood loss, and lower subsidence rates compared with the Zero-P implant or the titanium plate with a PEEK cage.

Respiratory Synchronized Versus Intermittent Pneumatic Compression in Prevention of Venous Thromboembolism After Total Joint Arthroplasty: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Elbuluk, Ameer M; Kim, Kelvin Y; Chen, Kevin K; Anoushiravani, Afshin A; Schwarzkopf, Ran; Iorio, Richard

2018-04-01

The objective of this study was to evaluate the efficacy of respiratory synchronized compression devices (RSCDs) versus nonsynchronized intermittent pneumatic compression devices (NSIPCDs) in preventing venous thromboembolism (VTE) after total joint arthroplasty. A systematic literature review was conducted. Data regarding surgical procedure, deep vein thrombosis, pulmonary embolism, mortality, and adverse events were abstracted. Compared with control groups, the risk ratio of deep vein thrombosis development was 0.51 with NSIPCDs and 0.47 with RSCDs. This review demonstrates that RSCDs may be marginally more effective at preventing VTE events than NSIPCDs. Furthermore, the addition of mechanical prophylaxis to any chemoprophylactic regimen increases VTE prevention. Copyright © 2017 Elsevier Inc. All rights reserved.

Auto fluorescence of intervertebral disc tissue: a new diagnostic tool.

Science.gov (United States)

Hoell, T; Huschak, G; Beier, A; Hüttmann, G; Minkus, Y; Holzhausen, H J; Meisel, H J

2006-08-01

The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

Angiogenesis in the degeneration of the lumbar intervertebral disc

OpenAIRE

David, Gh; Ciurea, AV; Iencean, SM; Mohan, A

2010-01-01

The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth ...

Lumbar disc herniation in patients with chronic backache.

Science.gov (United States)

Ali, Asghar; Khan, Shahbaz Ali; Aurangzeb, Ahsan; Ahmed, Ehtisham; Ali, Gohar; Muhammad, Gul; Mehmood, Shakir

2013-01-01

Low back pain with or without lower extremity pain is the most common problem among chronic pain disorders with significant economic, social, and health impact. This study was conducted to determine the frequency of lumbar disc herniation and its different levels, among patients with chronic backache. This cross sectional study was conducted in the department of Neurosurgery, Ayub Medical College Abbottabad from January 2011 to January 2013. All the patients presenting with chronic low backache of either gender above the age 14 years were included in the study. Magnetic resonance imaging (MRI) was done in all the patients included in the study to look for lumbar disc herniation. A total of 477 patients with chronic low backache were included in the study out of which 274 (57.4%) were males. Age of the patients ranged from 19 to 75 (39.92 +/- 12.31) years. Out of 477 patients 38 (7.9%) had significant radiological evidence of disc prolapse at lumbar vertebral levels, with 26 (9.5%) males and 12 (5.9%) females. Among these 38 patients with inter-vertebral disc, 20 (52.6%) of patients had disc herniation at L5-S1, 15 (39.5%) at L4-L5, 2 (5.26%) cases at L3-L4 level and only one case (2.6%) had the involvement of L2-L3 level. No cases of L1-L2 disc prolapse were found. Patients with chronic backache can have inter-vertebral lumbar disc prolapsed disease. Middle age group are more affected by lumbar disc disease especially at the lower lumbar regions.

Short-term clinical experience with hip resurfacing arthroplasty.

Science.gov (United States)

Cieliński, Łukasz; Kusz, Damian; Wojciechowski, Piotr; Dziuba, Anna

2007-01-01

This paper discusses the authors' experience with hip resurfacing arthroplasty. Although introduced many years ago, the method did not gain wide popularity because of poor long-term outcomes. At present, owing to the introduction of metal-on-metal bearings and hybrid fixation techniques, short- and mid-term results are very good and encourage wider use of this technique, especially in the younger and more active patients whose results with standard total hip replacements would be unsatisfactory. We performed 13 hip resurfacing arthroplasties at our institution between August 1, 2005, and May 1, 2006. Twelve patients reported for the scheduled follow-up and were included in the study. Treatment outcomes were assessed according to the Harris Hip Score. The short-term outcomes of hip resurfacing arthroplasties are encouraging. In the study group there were no intraoperative complications, infections, peripheral nerve palsy, hip dislocations or clinically overt vein thrombosis. All of the patients reported complete or major pain relief. Clinical assessment according to the Harris Hip Score revealed improvement from an average of 57.7 (20.1) points preoperatively to an average of 87.7 (12) points after the surgery. Crutches were used for a maximum of 6 weeks postoperatively. All of the patients are currently able to walk without crutches with full weight-bearing. 1) Hip resurfacing arthroplasty seems to be an advisable method of operative management of younger, active patients, in whom standard THR would be associated with a high risk of failure; it allows THR to be postponed and carried out as a revision surgery with the acetabular component already in place. 2) Despite the good short- and mid-term results, the utility of this method should be evaluated with caution due to the lack of adequate long-term follow-up data.

Tackling heterogeneity: a leaf disc-based assay for the high-throughput screening of transient gene expression in tobacco.

Directory of Open Access Journals (Sweden)

Natalia Piotrzkowski

Full Text Available Transient Agrobacterium-mediated gene expression assays for Nicotiana tabacum (N. tabacum are frequently used because they facilitate the comparison of multiple expression constructs regarding their capacity for maximum recombinant protein production. However, for three model proteins, we found that recombinant protein accumulation (rpa was significantly influenced by leaf age and leaf position effects. The ratio between the highest and lowest amount of protein accumulation (max/min ratio was found to be as high as 11. Therefore, construct-based impacts on the rpa level that are less than 11-fold will be masked by background noise. To address this problem, we developed a leaf disc-based screening assay and infiltration device that allows the rpa level in a whole tobacco plant to be reliably and reproducibly determined. The prototype of the leaf disc infiltration device allows 14 Agrobacterium-mediated infiltration events to be conducted in parallel. As shown for three model proteins, the average max/min rpa ratio was reduced to 1.4 using this method, which allows for a sensitive comparison of different genetic elements affecting recombinant protein expression.

Radiographic identification of ingested disc batteries

International Nuclear Information System (INIS)

Maves, M.D.

1986-01-01

Recently, the hazards by posed the accidental ingestion and impaction of small disc batteries have been widely publicized in the medical and lay press. These foreign bodies, when lodged in the esophagus, leak a caustic solution of 26 to 45% sodium or potassium hydroxide which can cause a burn injury to the esophagus in a very short period of time. Because of the considerable clinical morbidity and mortality from this foreign body, it becomes imperative for the radiologist to quickly and accurately identify disc batteries on plain radiographs. This communication offers a series of radiologic signs important in the identification of disc batteries demonstrate a double density shadow due to the bilaminar structure of the battery. On lateral view, the edges of most disc batteries are round and again present a step-off at the junction of the cathode and anode. These findings are differentiated from the more common esophageal foreign body of a coin which does not have a double density on frontal projection, has a much sharper edge and no visible stepoff. (orig.)

Increasing risk of prosthetic joint infection after total hip arthroplasty

DEFF Research Database (Denmark)

Dale, Håvard; Fenstad, Anne M; Hallan, Geir

2012-01-01

Background and purpose The risk of revision due to infection after primary total hip arthroplasty (THA) has been reported to be increasing in Norway. We investigated whether this increase is a common feature in the Nordic countries (Denmark, Finland, Norway, and Sweden). Materials and methods The...... explain this increase. We believe that there has been an actual increase in the incidence of prosthetic joint infections after THA.......Background and purpose The risk of revision due to infection after primary total hip arthroplasty (THA) has been reported to be increasing in Norway. We investigated whether this increase is a common feature in the Nordic countries (Denmark, Finland, Norway, and Sweden). Materials and methods...... The study was based on the Nordic Arthroplasty Register Association (NARA) dataset. 432,168 primary THAs from 1995 to 2009 were included (Denmark: 83,853, Finland 78,106, Norway 88,455, and Sweden 181,754). Adjusted survival analyses were performed using Cox regression models with revision due to infection...

Fundamental study on articular disc with magnetic resonance imagings

International Nuclear Information System (INIS)

Chiba, Toyokazu

1993-01-01

In order to establish criteria of reading MRI of the temporomandibular joint, a morphological comparison between MRI and the section, and an observation of the articular disc associated with the opening were made. Five temporomandibular joints isolated from 3 human cadavers were subjected to MRI, and sections were prepared to examine criteria of reading MRI. In 20 male adults, 40 temporomandibular joints underwent MRI in three conditions of the intercuspal position, 10 and 20 mm opening positions, and the kinetics of the articular disc were examined. External feature of the head of mandible and that of the articular fossa, the articular tubercule and the postglenoid process were outlined in a row of blacks. The articular disc was outlined in a row of dark ashen areas of the anterior band, the intermediate region, and the posterior band. In the intercuspal position, the head of mandible was rarely covered with the articular disc, and being situated postero-inferiorly, at the most rear point of the posterior band of the articular disc. In the 10 mm-opening position, the head of mandible was practically covered with the articular disc. In the 20 mm-opening position, the intermediate region of the articular disc, and the head of mandible were situated in an approximate position. Quantitative movement of the articular disc was slower than that of the head of mandible. Comparison of various points of the articular disc revealed that movements of the anterior and posterior band varied almost proportionally to the opening distance, but with lesser movement of the intermediate region. (author)

CT reconstruction technique in lumbar intraneuroforaminal disc herniation

International Nuclear Information System (INIS)

Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

1988-01-01

The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach. (orig.)

CT reconstruction technique in lumbar intraneuroforaminal disc herniation

Energy Technology Data Exchange (ETDEWEB)

Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

1988-04-01

The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach.

Magnetic-bubble devices

International Nuclear Information System (INIS)

Fairholme, R.J.

1978-01-01

Magnetic bubbles were first described only ten years ago when research workers were discussing orthoferrites containing μm diameter bubbles. However, problems of material fabrication limit crystals to a few mm across which severely curtailed device development. Since then materials have changed and rare-earth-iron garnet films can be grown up 3 inches in diameter with bubble diameters down to sizes below 1 μm. The first commercial products have device capacities in the range 64 000 to 100 000 bits with bubble diameters between 4 and 6 μm. Chip capacities of 1 Mbit are presently under development in the laboratory, as are new techniques to use submicrometre bubbles. The operation and fabrication of a bubble device is described using the serial loop devices currently being manufactured at Plessey as models. Chip organization is one important variable which directly affects the access time. A range of access times and capacities is available which offers a wide range of market opportunities, ranging from consumer products to fixed head disc replacements. some of the application areas are described. (author)

Cervical disc hernia operations through posterior laminoforaminotomy.

Science.gov (United States)

Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

2016-01-01

The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

Spiral density waves and vertical circulation in protoplanetary discs

Science.gov (United States)

Riols, A.; Latter, H.

2018-06-01

Spiral density waves dominate several facets of accretion disc dynamics - planet-disc interactions and gravitational instability (GI) most prominently. Though they have been examined thoroughly in two-dimensional simulations, their vertical structures in the non-linear regime are somewhat unexplored. This neglect is unwarranted given that any strong vertical motions associated with these waves could profoundly impact dust dynamics, dust sedimentation, planet formation, and the emissivity of the disc surface. In this paper, we combine linear calculations and shearing box simulations in order to investigate the vertical structure of spiral waves for various polytropic stratifications and wave amplitudes. For sub-adiabatic profiles, we find that spiral waves develop a pair of counter-rotating poloidal rolls. Particularly strong in the non-linear regime, these vortical structures issue from the baroclinicity supported by the background vertical entropy gradient. They are also intimately connected to the disc's g modes which appear to interact non-linearly with the density waves. Furthermore, we demonstrate that the poloidal rolls are ubiquitous in gravitoturbulence, emerging in the vicinity of GI spiral wakes, and potentially transporting grains off the disc mid-plane. Other than hindering sedimentation and planet formation, this phenomena may bear on observations of the disc's scattered infrared luminosity. The vortical features could also impact on the turbulent dynamo operating in young protoplanetary discs subject to GI, or possibly even galactic discs.

Collimation of particle beams from thick accretion discs

Energy Technology Data Exchange (ETDEWEB)

Sikora, M [N. Copernicus Astronomical Center, Warszawa (Poland); Wilson, D B [Cambridge Univ. (UK). Inst. of Astronomy

1981-11-01

The acceleration and collimation of particle beams in the funnel of thick accretion discs is studied in the approximation that the flow is optically thin. Such flows can be collimated to within approximately 0.1 radians by sufficiently thick discs. The flow cannot convert more than a small fraction of the disc's (super-Eddington) luminosity into the energy flow of a narrow beam without being optically thick.

Lunar phase does not influence perioperative complications in total hip arthroplasty.

Science.gov (United States)

Ficklscherer, Andreas; Angermann, Alexander; Weber, Patrick; Wegener, Bernd; Pietschmann, Matthias; Müller, Peter

2012-02-29

Lunar calendars, publishing recommendations for daily life, are gaining more and more attention in Germany, where 10.5% of the population believe in lunar effects on disease. A widespread and often heard belief is that a full moon has the most negative effects on surgical outcome. The present study evaluates the effects of lunar phase on perioperative complications in total hip arthroplasty. We performed a retrospective study with 305 patients being provided with a primary hip arthroplasty. To identify possible influences of the lunar phase on perioperative complications we investigated data such as operation length, blood loss and course of C-reactive protein that were collected during the patients' stay in the hospital and allocated them to moon illumination. There were no significant differences in all collected data concerning the lunar phase (p > 0.05). Although not statistically significant, there were fewer operations during the full moon phase. Therefore there is no evidence that lunar phase has an effect on perioperative complications in total hip arthroplasty. Fewer, though not significantly fewer, operations were performed during the full moon phase. Although this was not a prospective randomized trial, the statistical magnitude of the results does not support any recommendations for scheduling patients for total hip arthroplasty at any particular day of the lunar phase.

Metallicity gradient of the thick disc progenitor at high redshift

Science.gov (United States)

Kawata, Daisuke; Allende Prieto, Carlos; Brook, Chris B.; Casagrande, Luca; Ciucă, Ioana; Gibson, Brad K.; Grand, Robert J. J.; Hayden, Michael R.; Hunt, Jason A. S.

2018-01-01

We have developed a novel Markov Chain Monte Carlo chemical 'painting' technique to explore possible radial and vertical metallicity gradients for the thick disc progenitor. In our analysis, we match an N-body simulation to the data from the Apache Point Observatory Galactic Evolution Experiment survey. We assume that the thick disc has a constant scaleheight and has completed its formation at an early epoch, after which time radial mixing of its stars has taken place. Under these assumptions, we find that the initial radial metallicity gradient of the thick disc progenitor should not be negative, but either flat or even positive, to explain the current negative vertical metallicity gradient of the thick disc. Our study suggests that the thick disc was built-up in an inside-out and upside-down fashion, and older, smaller and thicker populations are more metal poor. In this case, star-forming discs at different epochs of the thick disc formation are allowed to have different radial metallicity gradients, including a negative one, which helps to explain a variety of slopes observed in high-redshift disc galaxies. This scenario helps to explain the positive slope of the metallicity-rotation velocity relation observed for the Galactic thick disc. On the other hand, radial mixing flattens the slope of an existing gradient.

Cost Analysis in Shoulder Arthroplasty Surgery

Directory of Open Access Journals (Sweden)

Matthew J. Teusink

2012-01-01

Full Text Available Cost in shoulder surgery has taken on a new focus with passage of the Patient Protection and Affordable Care Act. As part of this law, there is a provision for Accountable Care Organizations (ACOs and the bundled payment initiative. In this model, one entity would receive a single payment for an episode of care and distribute funds to all other parties involved. Given its reproducible nature, shoulder arthroplasty is ideally situated to become a model for an episode of care. Currently, there is little research into cost in shoulder arthroplasty surgery. The current analyses do not provide surgeons with a method for determining the cost and outcomes of their interventions, which is necessary to the success of bundled payment. Surgeons are ideally positioned to become leaders in ACOs, but in order for them to do so a methodology must be developed where accurate costs and outcomes can be determined for the episode of care.

Upper thoracic-spine disc degeneration in patients with cervical pain.

Science.gov (United States)

Arana, Estanislao; Martí-Bonmatí, Luis; Mollá, Enrique; Costa, Salvador

2004-01-01

To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6 +/- 14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P < 0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated ( P = 0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together ( P < 0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms.

Upper thoracic-spine disc degeneration in patients with cervical pain

Energy Technology Data Exchange (ETDEWEB)

Arana, Estanislao; Marti-Bonmati, Luis; Costa, Salvador [Department of Radiology, Clinica Quiron, Avda Blasco Ibanez 14, 46010, Valencia (Spain); Molla, Enrique [Department of Radiology, Clinica Quiron, Avda Blasco Ibanez 14, 46010, Valencia (Spain); Department of Morphological Sciences, University of Valencia, Valencia (Spain)

2004-01-01

To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6{+-}14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P<0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated (P=0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together (P<0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms. (orig.)

Human disc degeneration is associated with increased MMP 7 expression.

Science.gov (United States)

Le Maitre, C L; Freemont, A J; Hoyland, J A

2006-01-01

During intervertebral disc (IVD) degeneration, normal matrix synthesis decreases and degradation of disc matrix increases. A number of proteases that are increased during disc degeneration are thought to be involved in its pathogenesis. Matrix metalloproteinase 7 (MMP 7) (Matrilysin, PUMP-1) is known to cleave the major matrix molecules found within the IVD, i.e., the proteoglycan aggrecan and collagen type II. To date, however, it is not known how its expression changes with degeneration or its exact location. We investigated the localization of MMP 7 in human, histologically graded, nondegenerate, degenerated and prolapsed discs to ascertain whether MMP 7 is up-regulated during disc degeneration. Samples of human IVD tissue were fixed in neutral buffered formalin, embedded in paraffin, and sections stained with hematoxylin and eosin to score the degree of morphological degeneration. Immunohistochemistry was performed to localize MMP 7 in 41 human IVDs with varying degrees of degeneration. We found that the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus were MMP 7 immunopositive; little immunopositivity was observed in the outer annulus. Nondegenerate discs showed few immunopositive cells. A significant increase in the proportion of MMP 7 immunopositive cells was seen in the nucleus pulposus of discs classified as showing intermediate levels of degeneration and a further increase was seen in discs with severe degeneration. Prolapsed discs showed more MMP 7 immunopositive cells compared to nondegenerated discs, but fewer than those seen in cases of severe degeneration.

Upper thoracic-spine disc degeneration in patients with cervical pain

International Nuclear Information System (INIS)

Arana, Estanislao; Marti-Bonmati, Luis; Costa, Salvador; Molla, Enrique

2004-01-01

To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6±14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P<0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated (P=0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together (P<0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms. (orig.)

SPECT/CT in patients with painful knee arthroplasty - what is the evidence?

International Nuclear Information System (INIS)

Hirschmann, Michael T.; Henckel, Johann; Rasch, Helmut

2013-01-01

SPECT/CT is increasingly recognized as a promising imaging modality for the investigation of patients with a painful knee after knee arthroplasty. In this review article, we give an overview of the clinical value and current and future applications of SPECT/CT for patients with knee pain following joint arthroplasty. A detailed evidence-based literature review is performed and presented. (orig.)

SPECT/CT in patients with painful knee arthroplasty - what is the evidence?

Energy Technology Data Exchange (ETDEWEB)

Hirschmann, Michael T. [Kantonsspital Baselland-Bruderholz, Department of Orthopaedic Surgery and Traumatology, Bruderholz (Switzerland); Henckel, Johann [Imperial College London, London (United Kingdom); Rasch, Helmut [Kantonsspital Baselland-Bruderholz, Institute for Radiology and Nuclear Medicine, Bruderholz (Switzerland)

2013-09-15

SPECT/CT is increasingly recognized as a promising imaging modality for the investigation of patients with a painful knee after knee arthroplasty. In this review article, we give an overview of the clinical value and current and future applications of SPECT/CT for patients with knee pain following joint arthroplasty. A detailed evidence-based literature review is performed and presented. (orig.)

Effect of hydroxyapatite coating on risk of revision after primary total hip arthroplasty in younger patients: findings from the Danish Hip Arthroplasty Registry

DEFF Research Database (Denmark)

Paulsen, Aksel; Pedersen, Alma B; Johnsen, Søren P

2007-01-01

BACKGROUND: The effect of hydroxyapatite (HA) on implant survival in the medium and long term is uncertain. We studied the effect of HA coating of uncemented implants on the risk of cup and stem revision in primary total hip arthroplasty (THA). PATIENTS AND METHODS: Using the Danish Hip Arthropla......BACKGROUND: The effect of hydroxyapatite (HA) on implant survival in the medium and long term is uncertain. We studied the effect of HA coating of uncemented implants on the risk of cup and stem revision in primary total hip arthroplasty (THA). PATIENTS AND METHODS: Using the Danish Hip...

Surgical Stabilization of the Medial Capsulo-Ligamentous Envelope in Total Knee Arthroplasty

Directory of Open Access Journals (Sweden)

Brandon Green, DO

2014-10-01

Full Text Available This study will evaluate an alternative method in which a four prong bone staple was used to repair the medial collateral ligament following over-release or avulsion injuries in (#6 cases during a total knee arthroplasty. The use of a four prong bone staple to repair medial collateral ligament injuries status post total knee replacement will provide satisfactory results with respect to post-operative knee stability and range of motion. Our retrospective review revealed that all six patients improved with regards to range of motion following the total knee arthroplasty. We feel that repair of the medial collateral ligament with a four-prong bone staple is a viable option after an over-release or avulsion injury sustained during a total knee arthroplasty.

Nurses' responsibilities in postoperative pain management following total hip arthroplasty

OpenAIRE

Dumolard, Pierre; Gök, Mustafa; Le, Ngoc

2017-01-01

Total hip arthroplasty is the replacement of a hip joint that has been severely damaged. The operation is recommended if other treatments have not responded adequately. As the nurses are the professionals who spend the most time with patients after the surgery, they play an important role in the patient’s pain management. The aim of the thesis is to define the nurse’s responsibilities in the care of total hip arthroplasty. The purpose of the thesis is to analyze existing research, which may s...

Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

Science.gov (United States)

Chiang, Jaclyn; Yapp, Michael; Ly, Angelica; Hennessy, Michael P; Kalloniatis, Michael; Zangerl, Barbara

2018-03-01

This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

PATHOGENESIS OF OPTIC DISC EDEMA IN RAISED INTRACRANIAL PRESSURE

Science.gov (United States)

Hayreh, Sohan Singh

2015-01-01

Optic disc edema in raised intracranial pressure was first described in 1853. Ever since, there has been a plethora of controversial hypotheses to explain its pathogenesis. I have explored the subject comprehensively by doing basic, experimental and clinical studies. My objective was to investigate the fundamentals of the subject, to test the validity of the previous theories, and finally, based on all these studies, to find a logical explanation for the pathogenesis. My studies included the following issues pertinent to the pathogenesis of optic disc edema in raised intracranial pressure: the anatomy and blood supply of the optic nerve, the roles of the sheath of the optic nerve, of the centripetal flow of fluids along the optic nerve, of compression of the central retinal vein, and of acute intracranial hypertension and its associated effects. I found that, contrary to some previous claims, an acute rise of intracranial pressure was not quickly followed by production of optic disc edema. Then, in rhesus monkeys, I produced experimentally chronic intracranial hypertension by slowly increasing in size space-occupying lesions, in different parts of the brain. Those produced raised cerebrospinal fluid pressure (CSFP) and optic disc edema, identical to those seen in patients with elevated CSFP. Having achieved that, I investigated various aspects of optic disc edema by ophthalmoscopy, stereoscopic color fundus photography and fluorescein fundus angiography, and light microscopic, electron microscopic, horseradish peroxidase and axoplasmic transport studies, and evaluated the effect of opening the sheath of the optic nerve on the optic disc edema. This latter study showed that opening the sheath resulted in resolution of optic disc edema on the side of the sheath fenestration, in spite of high intracranial CSFP, proving that a rise of CSFP in the sheath was the essential pre-requisite for the development of optic disc edema. I also investigated optic disc edema with

Loss of knee-extension strength is related to knee swelling after total knee arthroplasty

DEFF Research Database (Denmark)

Holm, Bente; Kristensen, Morten T; Bencke, Jesper

2010-01-01

To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA).......To examine whether changes in knee-extension strength and functional performance are related to knee swelling after total knee arthroplasty (TKA)....

Herniated Cervical Disc

Science.gov (United States)

... are sometimes prescribed for more severe arm and neck pain because of their very powerful anti-inflammatory effect. ... caused by a herniated cervical disc. However, some neck pain may persist. Most patients respond well to discectomy; ...

Hybrid testing of lumbar CHARITE discs versus fusions.

Science.gov (United States)

Panjabi, Manohar; Malcolmson, George; Teng, Edward; Tominaga, Yasuhiro; Henderson, Gweneth; Serhan, Hassan

2007-04-20

An in vitro human cadaveric biomechanical study. To quantify effects on operated and other levels, including adjacent levels, due to CHARITE disc implantations versus simulated fusions, using follower load and the new hybrid test method in flexion-extension and bilateral torsion. Spinal fusion has been associated with long-term accelerated degeneration at adjacent levels. As opposed to the fusion, artificial discs are designed to preserve motion and diminish the adjacent-level effects. Five fresh human cadaveric lumbar specimens (T12-S1) underwent multidirectional testing in flexion-extension and bilateral torsion with 400 N follower load. Intact specimen total ranges of motion were determined with +/-10 Nm unconstrained pure moments. The intact range of motion was used as input for the hybrid tests of 5 constructs: 1) CHARITE disc at L5-S1; 2) fusion at L5-S1; 3) CHARITE discs at L4-L5 and L5-S1; 4) CHARITE disc at L4-L5 and fusion at L5-S1; and 5) 2-level fusion at L4-L5-S1. Using repeated-measures single factor analysis of variance and Bonferroni statistical tests (P < 0.05), intervertebral motion redistribution of each construct was compared with the intact. In flexion-extension, 1-level CHARITE disc preserved motion at the operated and other levels, while 2-level CHARITE showed some amount of other-level effects. In contrast, 1- and 2-level fusions increased other-level motions (average, 21.0% and 61.9%, respectively). In torsion, both 1- and 2-level discs preserved motions at all levels. The 2-level simulated fusion increased motions at proximal levels (22.9%), while the 1-level fusion produced no significant changes. In general, CHARITE discs preserved operated- and other-level motions. Fusion simulations affected motion redistribution at other levels, including adjacent levels.

Long-term results of patellofemoral arthroplasty - A report of 56 arthroplasties with 17 years of follow-up

NARCIS (Netherlands)

Kooijman, HJ; Driessen, APPM; van Horn, [No Value

We studied retrospectively the outcome of patellofemoral arthroplasty (PFA) using the Richards prosthesis in 51 patients (56 knees). Their mean age was 50 years (30 to 77). In 43 patients (45 knees), the American Knee Society score and the patients' subjective judgement were assessed. Excellent or

Transcatheter Retrieval of Embolized Atrial Septal Defect Occluder Device by Waist Capture Technique.

Science.gov (United States)

Her, Ae-Young; Lim, Kyung-Hun; Shin, Eun-Seok

2018-01-27

This case study describes the successful percutaneous transcatheter retrieval of an embolized Amplatzer occluder device using the "waist capture technique" in a patient with an atrial septal defect. This technique allowed for stability of the Amplatzer device, compression of the atrial discs for easier removal, prevention of further embolization, and minimal injury to vasculature during device retrieval. This novel and effective technique can be used safely for the retrieval of Amplatzer devices in the venous system.

In-Home Telerehabilitation for Post-Knee Arthroplasty: A Pilot Study

Directory of Open Access Journals (Sweden)

Michel Tousignant

2009-09-01

Full Text Available The purpose of this study was to investigate the efficacy of in-home telerehabilitation as an alternative to conventional rehabilitation services following knee arthroplasty. Five community-living elders who had knee arthroplasty were recruited prior to discharge from an acute care hospital. A pre/post-test design without a control group was used for this pilot study. Telerehabilitation sessions (16 were conducted by two trained physiotherapists from a service center to the patient’s home using H264 videoconference CODECs (Tandberg 550 MXP connected at 512 Kb\\s. Disability (range of motion, balance and lower body strength and function (locomotor performance in walking and functional autonomy were measured in face-to-face evaluations prior to and at the end of the treatments by a neutral evaluator. The satisfaction of the health care professional and patient was measured by questionnaire. Results are as follows. One participant was lost during follow-up. Clinical outcomes improved for all subjects and improvements were sustained two months post-discharge from in-home telerehabilitation. The satisfaction of the participants with in-home telerehabilitation services was very high. The satisfaction of the health care professionals with the technology and the communication experience during the therapy sessions was similar or slightly lower. In conclusion, telerehabilitation for post-knee arthroplasty is a realistic alternative for dispensing rehabilitation services for patients discharged from an acute care hospital.Keywords: Telerehabilitation, Physical Therapy, Total Knee Arthroplasty, Videoconferencing

Magnetic fields in giant planet formation and protoplanetary discs

Science.gov (United States)

Keith, Sarah Louise

2015-12-01

Protoplanetary discs channel accretion onto their host star. How this is achieved is critical to the growth of giant planets which capture their massive gaseous atmosphere from the surrounding flow. Theoretical studies find that an embedded magnetic field could power accretion by hydromagnetic turbulence or torques from a large-scale field. This thesis presents a study of the inuence of magnetic fields in three key aspects of this process: circumplanetary disc accretion, gas flow across gaps in protoplanetary discs, and magnetic-braking in accretion discs. The first study examines the conditions needed for self-consistent accretion driven by magnetic fields or gravitational instability. Models of these discs typically rely on hydromagnetic turbulence as the source of effective viscosity. However, magnetically coupled,accreting regions may be so limited that the disc may not support sufficient inflow. An improved Shakura-Sunyaev ? disc is used to calculate the ionisation fraction and strength of non-ideal effects. Steady magnetically-driven accretion is limited to the thermally ionised, inner disc so that accretion in the remainder of the disc is time-dependent. The second study addresses magnetic flux transport in an accretion gap evacuated by a giant planet. Assuming the field is passively drawn along with the gas, the hydrodynamical simulation of Tanigawa, Ohtsuki & Machida (2012) is used for an a posteriori analysis of the gap field structure. This is used to post-calculate magnetohydrodynamical quantities. This assumption is self-consistent as magnetic forces are found to be weak, and good magnetic coupling ensures the field is frozen into the gas. Hall drift dominates across much of the gap, with the potential to facilitate turbulence and modify the toroidal field according to the global field orientation. The third study considers the structure and stability of magnetically-braked accretion discs. Strong evidence for MRI dead-zones has renewed interest in

Analysis of an Assemblage of Discs Employing Interactive Graphics.

Science.gov (United States)

1980-12-01

facilitate the program’s efficiency. Indeed, the ulsabilitv of tie distinct element method is pred icated on ef f ic ielt Irogramming techniques...paragraphs. Any subsequent user of DISC should not necessarily feel bound to this scheme. 33. At the outset of writing DISC, it was decided that a disc

Utility of Digital Stereo Images for Optic Disc Evaluation

Science.gov (United States)

Ying, Gui-shuang; Pearson, Denise J.; Bansal, Mayank; Puri, Manika; Miller, Eydie; Alexander, Judith; Piltz-Seymour, Jody; Nyberg, William; Maguire, Maureen G.; Eledath, Jayan; Sawhney, Harpreet

2010-01-01

Purpose. To assess the suitability of digital stereo images for optic disc evaluations in glaucoma. Methods. Stereo color optic disc images in both digital and 35-mm slide film formats were acquired contemporaneously from 29 subjects with various cup-to-disc ratios (range, 0.26–0.76; median, 0.475). Using a grading scale designed to assess image quality, the ease of visualizing optic disc features important for glaucoma diagnosis, and the comparative diameters of the optic disc cup, experienced observers separately compared the primary digital stereo images to each subject's 35-mm slides, to scanned images of the same 35-mm slides, and to grayscale conversions of the digital images. Statistical analysis accounted for multiple gradings and comparisons and also assessed image formats under monoscopic viewing. Results. Overall, the quality of primary digital color images was judged superior to that of 35-mm slides (P digital color images were mostly equivalent to the scanned digitized images of the same slides. Color seemingly added little to grayscale optic disc images, except that peripapillary atrophy was best seen in color (P digital over film images was maintained under monoscopic viewing conditions. Conclusions. Digital stereo optic disc images are useful for evaluating the optic disc in glaucoma and allow the application of advanced image processing applications. Grayscale images, by providing luminance distinct from color, may be informative for assessing certain features. PMID:20505199

Challenges in the Use of Compact Disc-Based Centrifugal Microfluidics for Healthcare Diagnostics at the Extreme Point of Care

Directory of Open Access Journals (Sweden)

Jordon Gilmore

2016-03-01

Full Text Available Since its inception, Compact Disc (CD-based centrifugal microfluidic technology has drawn a great deal of interest within research communities due to its potential use in biomedical applications. The technology has been referred to by different names, including compact-disc microfluidics, lab-on-a-disk, lab-on-a-CD and bio-disk. This paper critically reviews the state-of-the-art in CD-based centrifugal microfluidics devices and attempts to identify the challenges that, if solved, would enable their use in the extreme point of care. Sample actuation, manufacturing, reagent storage and implementation, target multiplexing, bio-particle detection, required hardware and system disposal, and sustainability are the topics of focus.

On the formation of exponential discs