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At least 487 records · Page 27Linked to original sources
PubMed2000

Fluid retention in Bioplasty Misti Gold II breast prostheses with development of capsular contracture.

We compared the incidence of capsular contracture in an implant (Bioplasty Misti Gold II) which has a textured surface and is filled with polyvinyl-pirrolidone (PVP)-hydrogel, with that in saline-filled implants with textured surfaces when the implants are placed subcutaneously during immediate reconstruction after subcutaneous mastectomy. In 41 patients, mean age 55 years (range 30-81), with breast cancer that was not suitable for breast conservation, 20 patients had 22 Misti Gold II prostheses inserted (two patients bilaterally) and 21 patients had saline-filled prostheses (one patient bilaterally). The development of capsular contracture was assessed using Baker's classification and applanation tonometry. Fourteen patients with Misti Gold II implants were classified one year postoperatively as Baker 2 and 3 compared with five with saline-filled implants (p = 0.01). On applanation tonometry 16 of the Misti Gold II group had an operative:postoperative ratio of < or = 0.75, compared with 50% in the saline-filled group (p = 0.096). In the 12 Misti Gold II prostheses that were removed because of capsular contracture between 13-40 months postoperatively, the volume in the prostheses had increased by 48%. The poor results obtained with the Misti Gold II prosthesis can be explained by the volume that they gained after implantation as a result of osmosis.

Adult↗
PubMed2000

Evaluation of polypropylene prostheses designed by the International Committee of the Red Cross for trans-tibial amputees.

Thirty-two (32) trained prosthesis users with 34 trans-tibial amputations, mostly due to war, were fitted with prostheses fabricated from polypropylene (PP) prosthetic components designed and manufactured by the International Committee of the Red Cross (ICRC). The patients were followed prospectively for 10 and 19 months. All but one patient had at least one other type of prosthesis to compare with. Twenty-eight (28) patients were satisfied with the PP prosthesis. Among these 23 found the PP prosthesis the preferred artificial limb, and one patient found the PP limb equal to the aluminium prosthesis previously in use. In 6/28 patients having an aluminium (ALU) prostheses this was found the best, and the 1 already mentioned found it equivalent to the new technology. In only 1/20 cases having an Automated Fabrication of Mobility Aids (AFMA) prosthesis available this was found the best. One (1) double-amputee found all three designs equal. Minor failures of the PP prostheses were encountered; in 4 cases small cracks in the hard socket; in 3 cases cracks of the cosmetic socket seam. From an overall prospect the PP technology can be recommended for trans-tibial prostheses.

Adult↗
PubMed2001

Silicone roll-on suspension for upper limb prostheses: users' views.

OBJECTIVE: To determine the perceived benefit, pattern of use and problems of the ICEROSS socket for upper limb prostheses. DESIGN: Structured questionnaire sent to patients provided with ICEROSS systems. SETTING: NHS artificial limb clinic. SUBJECTS: All patients (20) who have used an upper limb prosthesis with an ICEROSS inner socket between 1995-1999. MAIN OUTCOME MEASURES: Purpose-designed questionnaire. RESULTS: Replies were obtained from 18 patients. Eight (8) amputees continue to use their ICEROSS limb regularly (44%) after a mean of 32 months. Ten (10) amputees stopped using the ICEROSS system. Six (6) developed persistent skin problems, 2 switched to myoelectric prostheses, 1 was unable to put the ICEROSS on independently and 1 amputee stopped using all kinds of prostheses because he did not find them useful. Fourteen (14) amputees complained of phantom pain, 4 of whom reported worsening of the pain with ICEROSS sockets. CONCLUSION: The ICEROSS socket provides good suspension for upper limb prostheses, but its use is limited by skin problems and incompatibility with myoelectric contacts.

Adolescent↗
PubMed2006

Can partial foot prostheses effectively restore foot length?

Our understanding of how partial foot prostheses function stems from static force analyses, where assumptions about the location of the ground reaction force during terminal stance have been made. While such assumptions seemed reasonably based on an understanding of normal gait, they are often illogical based on what is observed clinically. As such, the aim of this work was to evaluate the belief that partial foot prostheses are able to restore the effective foot length. Centre of pressure (CoP) excursion data were collected as part of a complete gait analysis incorporating an Advanced Mechanical Technology Inc. force platform. The CoP excursion patterns, observed in a cohort of eight partial foot amputees and matched control subjects, highlight the inability of toe fillers and slipper sockets to restore the 'effective' foot length in transmetatarsal and Lisfranc amputees, whereas clamshell prostheses fitted to the Chopart amputees were able to restore the effective foot length. In the transmetatarsal and Lisfranc amputees, the observed CoP excursion patterns could indicate a learned gait strategy necessary to reduce the requirement of the weak triceps surae musculature as well as spare the sensitive distal stump from extreme forces. The toe fillers and slipper sockets fitted to these amputees may not be stiff enough to support the amputee's body weight or the device may not be designed appropriately to assist the weakened triceps musculature to resist the external moments caused by loading the forefoot. The clamshell prostheses restored the 'effective' foot length due to the rigid toe lever and clamshell socket, which could allow and comfortably support the generation of substantial external moments during terminal stance.

Adult↗
PubMed1992

Doppler haemodynamic profiles of clinically and echocardiographically normal mitral and aortic valve prostheses.

Doppler echocardiographic studies were performed in 380 consecutive patients with 415 normally functioning artificial valves to establish normal Doppler characteristics for each type of prostheses used in our institution, with particular reference to Starr-Edwards valves, and to serve as control studies for future assessment. None of the patients were in heart failure at the time of the study. Peak transaortic velocities (m.s-1) were higher and effective orifice areas (cm2) smaller in mechanical valves as a whole, when compared with bioprostheses (P less than 0.01); 2.7 +/- 0.7 and 1.4 +/- 0.55 for Starr-Edwards, 2.7 +/- 0.6 and 1.5 +/- 0.6 for Bjork-Shiley, 1.8 +/- 0.1 and 1.5 +/- 0.6 for Duromedics and 1.5 +/- 0.06 and 2 +/- 0.12 for bioprostheses, respectively. In the mitral position, the average peak diastolic velocities (m. s-1) and pressure half-times (ms) were higher in mechanical valves, but there was a large overlap between the various types and sizes of prostheses (P = NS); 1.6 +/- 0.3 and 98 +/- 25 for Starr-Edwards, 1.4 +/- 0.3 and 88 +/- 26 for Bjork-Shiley, 1.8 +/- 0.1 and 75 +/- 5 for Duromedics and 1.5 +/- 0.3 and 90 +/- 20 for bioprostheses, respectively. There was an inverse relation between valve size and pressure halftime for Starr-Edwards prostheses (P less than 0.01). Doppler flow characteristics in mechanical valves where similar in patients with normal and dysfunctioning prostheses. Valvular or myocardial dysfunction could best be ascertained when early postoperative studies were available for comparison.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

The friction of explanted hip prostheses.

Charnley prostheses, retrieved at revision surgery, were studied to assess the effects of friction on the total hip replacement procedure. Frictional resistance was measured using the Durham hip function simulator under both dry and lubricated conditions. The friction factor values (f) for the explanted prostheses were found to have a non-Gaussian distribution with medians of 0.13 [inter-quartile range (IQR) 0.10-0.16] and 0.06 (IQR 0.005-0.08) for dry and lubricated (n = 0.01 Pa s) regimes, respectively. New Charnley prostheses had values of f equal to 0.11 +/- 0.025 and 0.04 +/- 0.01 under the same conditions, and showed no large deviation from a Gaussian distribution. There was found to be a statistically significant difference in the medians of the friction factors for new and retrieved prostheses in the lubricated regime. Ingression of cement into the worn region of the cup was found to increase the friction factor significantly under dry conditions. There was no evidence of an increase in the friction factor or torque for those joints that had a loose socket with respect to those that were fixed at revision. A decrease in the frictional torque against number of cycles undergone by the joint in vivo may indicate that a fatigue-type process may have a role in the loosening of the socket. However, this relationship was found not to be significant for friction measured under lubricated conditions and it seems unlikely that the frictional torque generated in this type of prosthesis will contribute significantly to the long-term loosening of the socket.

Adult↗
PubMed1988

Prospective study of sequential technetium-99m phosphate and gallium imaging in painful hip prostheses (comparison of diagnostic modalities).

Twenty-two painful hip prostheses were studied prospectively with plain radiography, aspiration and arthrography, Tc-99m phosphate bone imaging, and gallium imaging to evaluate loosening, infection, or both and to compare the accuracy of these modalities. Fifteen prostheses were revised yielding 14 loose femoral and eight loose acetabular components. Five proved to have infected prostheses. Arthrograms, plain radiographs, and bone scans are highly sensitive in detecting loosening of the femoral component. This study confirmed a previous retrospective study in demonstrating that accuracy of diagnosis of an abnormal acetabular component using all four modalities is less than that for the femoral component. In infected prostheses, phosphate bone imaging showed high sensitivity of a pattern that accurately diagnosed all the infected cases, whereas gallium imaging missed one case.

Adult↗
PubMed1999

Functional results of Plastipore prostheses for middle ear ossicular chain reconstruction.

OBJECTIVE: Assessment of plastipore prostheses for middle ear ossicular chain reconstruction. Hearing results with total and partial Plastipore ossicular replacement prostheses (TORP and PORP) were evaluated in open- and closed-cavity operations. STUDY DESIGN: A retrospective review of 237 patients who underwent operation for chronic ear disease as well as ossiculoplasty with plastipore prostheses. In order to assess the functional results, only 156 of 237 patients were included in the study. Follow-up ranged from 6 to 46 months. METHODS: Canal wall up and canal wall down operations were performed. Either TORP or PORP ossiculoplasty was performed in each operation. An airbone gap closure to within 20 dB was considered successful. RESULTS: With TORPs, the airbone gap closure to within 20 dB was achieved in 43.1%, and similar results were obtained with PORPs in 63.3%. In canal wall down and canal wall up operations, the success rates were 55.8% and 55.7%, respectively. The best results were obtained with PORPs in canal wall down operations, with a success rate of 82%. The extrusion rate of the prostheses was 4.2%. CONCLUSION: Hearing results of PORPs are better than TORPs. In canal wall up and canal wall down operations similar hearing results are obtained. PORP ossiculoplasty in a canal wall down operation yields the most favorable hearing result.

Adolescent↗
PubMed2002

Colonization of voice prostheses by albicans and non-albicans Candida species.

OBJECTIVES: The purposes of the study were to assess the colonization of tracheoesophageal voice prostheses by albicans and non-albicans Candida species and to determine their susceptibility for three antimycotics that are frequently used for prophylaxis or treatment of oral candidiasis (i.e., miconazole, fluconazole, and nystatin). STUDY DESIGN: In total, 101 patients, corresponding to 170 voice prostheses, were monitored over a period of 28 months. METHODS: An enzymatic two-step method was used for differentiation and presumptive identification of Candida species colonizing the voice prostheses. The identity of the isolates was confirmed by the germ-tube test, morphological appearance on cornmeal agar with 0.5% Tween 80, sugar assimilation tests, and appearance on CHROMagar Candida (CHROMagar Co., Paris), Albicans ID (BioMérieux Vitek, Hazelwood, MO), and Fluoroplate Candida (Merck, Darmstadt, Germany). Susceptibility testing for miconazole, fluconazole, and nystatin was performed according to the microdilution method of the National Committee for Clinical Laboratory Standards. RESULTS: The predominant species isolated were Candida albicans (41.4%), Candida glabrata (33.1%), Candida krusei (15.9%), and Candida tropicalis (5.3%). A broad range of minimal inhibitory concentrations of the isolates was observed for miconazole and fluconazole. In contrast, minimal inhibitory concentration values for nystatin were narrowly distributed around 4 microg/mL for all isolates, suggesting uniform sensitivity. CONCLUSION: Our data on the prevalence and susceptibility of yeast isolates will contribute to a rational choice of an antimycotic for prophylaxis of the early deterioration and leakage of tracheoesophageal voice prostheses.

Aged↗
PubMed2003

A method to intraoperatively assess stapes prostheses for magnetic attraction.

OBJECTIVE: To present a technique used to assess metallic otologic prostheses for magnetic susceptibility during surgery. STUDY DESIGN: Description of a surgical technique. METHODS: A sterile handheld pacemaker magnet is used to evaluate the prosthesis prior to implantation. The magnet is placed over the prosthesis and the prosthesis is placed directly on the magnet. Any evidence of magnetic attraction and the prosthesis is rejected prior to implantation. RESULTS: None of the prostheses screened showed any magnetic attraction. As a control, steel wire was cut into pieces with dimensions similar to prostheses. These sections of wire were readily attracted to the magnet. CONCLUSIONS: Intraoperative screening of metallic prostheses for magnetic susceptibility is possible using a sterile handheld pacemaker magnet.

Intraoperative Period↗
PubMed2004

Results with titanium ossicular reconstruction prostheses.

OBJECTIVES/HYPOTHESIS: Despite the enthusiasm of recent short-term reviews, no center in the United States has published results meeting American Academy of Otolaryngology-Head and Neck Surgery guidelines with titanium-based prostheses. The purpose of the study was threefold. The first purpose was to review results with a titanium prosthesis system in cases meeting American Academy of Otolaryngology-Head and Neck Surgery reporting guidelines. The second was to compare these results with previously published results using non-titanium-based prostheses. The third was to examine the authors' results for any evidence of a "learning curve." STUDY DESIGN: Retrospective chart review was performed for the period from February 2000 to August 2001 and for the period from July 2002 to February 2003. METHODS: Of 313 cases, 130 consecutive cases were identified in the first period and 65 in the second time period. One hundred two patients had adequate follow-up for published guidelines. All cases were performed by the senior author (c.g.j.). Comparison data were obtained from a previous publication involving the senior author. RESULTS: Successful rehabilitation (<or=20 dB pure-tone average air-bone gap) of conductive hearing loss was obtained in 70% of partial ossicular chain reconstructions and 44% of total ossicular chain reconstructions when titanium prostheses were used. Comparison data revealed successful rehabilitation in 48% and 21% of non-titanium-based partial and total reconstructions, respectively. Postoperative pure-tone average air-bone gaps were not significantly different when compared with results in the period from July 2002 to February 2003. CONCLUSION: Newer titanium-based ossicular reconstruction devices represent an improvement over previously used non-titanium-based prostheses. The authors think that this improvement is realized rapidly because no learning curve existed in their data.

Bone Conduction↗
PubMed1995

Tissue humoral response to intact and ruptured silicone gel-filled prostheses.

Biopsies of the fibrous capsule in 31 women undergoing explanation of gel-filled breast prostheses and in 3 women with silicone gel-associated granulomas were tested for the presence of IgG, IgM, IgA, C3 complement, and fibrin using fluorescent antisera. Of a total of 41 prostheses removed, 9 were found to be ruptured but contained within the fibrous capsule or immediately adjacent to it. In the 3 women undergoing granuloma excision only, the sites were the arm (2) and the chest/axilla (1). In one patient, IgG, C3, and fibrin were detected in the capsule of an intact prosthesis. C3 and fibrin were present in the capsule surrounding one ruptured prosthesis. Fibrin was detected in the capsule of one other patient. Bilateral capsules surrounding intact prostheses removed from 4 patients with collage-vascular diseases were negative for C3, fibrin, and immunoglobulins, as were the 3 granulomas from distant sites. Hematoxylin and eosin stains revealed a typical foreign-body response to gel in almost all cases. Both T- and B-cell lymphocytes are present in the infiltrate surrounding silicone gel. In this study, chronic exposure to silicone gel-filled prostheses did not result in antibody deposition or complement activation in the fibrous capsule or in the tissue surrounding gel droplets.

Antibody Formation↗
PubMed1997

Unusual masses found within ruptured silicone gel breast prostheses.

Imaging of breast implants has assumed more importance in medicine than ever before. Radiologists and surgeons alike have struggled to accurately identify folds in prostheses, rupture of prostheses, and migration of gel. Here we present two patients with an unusual presentation of masses within the gel of ruptured silicone gel-containing prostheses. In one instance, the mass was an organized hematoma. In the other, two round, calcified masses were found that we presume are hematomas that have become calcified over time. Radiologists and surgeons identifying spherical or ovoid masses seemingly within gel breast prostheses should entertain the possibility that the mass represents an organized hematoma and that the implant is ruptured.

Breast Implants↗
PubMed2003

Salvage of infected expander prostheses in breast reconstruction.

Periprosthetic infection is a devastating complication following breast reconstruction with prostheses. Traditional surgical principles dictate removal of the prosthesis to control infection. Although successful salvage of prostheses in the presence of periprosthetic infections has been reported in the plastic and other surgical literature, salvage procedures remain seldom practiced. Reports in the plastic surgery literature have been limited to implant salvage following cosmetic breast augmentation and subcutaneous mastectomy with implants. Salvage of saline-filled expander prostheses used in breast reconstruction following mastectomy for cancer has not been previously reported. The authors review their experience with implant salvage in patients with periprosthetic infections following breast reconstruction for a 6-year period. Fourteen patients (13 with saline-filled expander prostheses and one with silicone prosthesis) underwent implant salvage. Salvage of the breast reconstruction was successful in nine patients. Staphylococcus aureus infection was associated with poorer salvage rate (p = 0.023). Previous radiotherapy to the chest wall did not affect the salvage outcome (p = 0.50). In selected patients, immediate salvage of a breast reconstruction in the presence of prosthesis-related infection remains an alternative to implant removal followed by delayed reconstruction.

Adult↗
PubMed2000

X-ray CT metal artifact reduction using wavelets: an application for imaging total hip prostheses.

Traditional computed tomography (CT) reconstructions of total joint prostheses are limited by metal artifacts from corrupted projection data. Published metal artifact reduction methods are based on the assumption that severe attenuation of X-rays by prostheses renders corresponding portions of projection data unavailable, hence the "missing" data are either avoided (in iterative reconstruction) or interpolated (in filtered backprojection with data completion; typically, with filling data "gaps" via linear functions). In this paper, we propose a wavelet-based multiresolution analysis method for metal artifact reduction, in which information is extracted from corrupted projection data. The wavelet method improves image quality by a successive interpolation in the wavelet domain. Theoretical analysis and experimental results demonstrate that the metal artifacts due to both photon starving and beam hardening can be effectively suppressed using our method. As compared to the filtered backprojection after linear interpolation, the wavelet-based reconstruction is significantly more accurate for depiction of anatomical structures, especially in the immediate neighborhood of the prostheses. This superior imaging precision is highly advantageous in geometric modeling for fitting hip prostheses.

Artifacts↗
PubMed1995

Three-dimensional distortion of gold alloy castings and welded titanium frameworks. Measurements of the precision of fit between completed implant prostheses and the master casts in routine edentulous situations.

Thirty routine patients, provided with fixed prostheses supported by osseointegrated Brånemark implants in edentulous lower jaws, were arranged into three different groups with regard to design of the metal framework. Ten patients received cast gold alloy frames and the other two groups were provided with two different designs of welded titanium frames. The fit of the completed prostheses was measured in three dimensions (3-D) in relation to the master cast, by means of a photogrammetric technique, prior to insertion. Mean 3-D distortion of the centre point of the gold cylinder was 42 (s.d. 8) microns for the cast framework. The corresponding mean distortion for the two designs of titanium frameworks was 43 (s.d. 16) and 36 (s.d. 10) microns, respectively. Least distortion was observed in vertical direction for all three designs. None of the different designs of metal frames showed a significantly better fit (P > 0.05), but the cast and oldest titanium framework design presented a much wider range of distortion. This indicated a higher risk of sectioning and resoldering during the fabrication of the prostheses as compared to the more consistently fabricated prostheses, with a new titanium framework design.

Dental Casting Technique↗
PubMed2005

Thrombin-free fibrin coating on small caliber vascular prostheses has high antithrombogenicity in rabbit model.

Fibrin coatings on prosthetic vascular graft, which are conventionally produced by fibrinogen and thrombin, are expected to improve antithrombogenicity and healing characteristics. Thrombin is one of the factors of blood coagulation cascade; however, it has a possibility to play a negative role in the graft antithrombogenicity. The purpose of this study was to evaluate the performance of our new grafts, thrombin-free fibrin-coated small caliber vascular prostheses. Knitted polyester fabric vascular prostheses 2 mm in internal diameter were coated with fibrin coating with thrombin (Graft I) or without thrombin (Graft II). Both grafts were implanted in bilateral common carotid arteries of 35 Japanese white rabbits, with Graft I in one side and Graft II in the contralateral side. Graft patency, histology, thrombin activity, and platelet deposition were compared between both grafts on postoperative days (PODs) 1, 3, 7, 10, 14, 30, and 60. Both grafts were patent without thrombus or stenosis at each end point (maximal period, POD 60). Macro- and microscopic findings revealed that no obvious difference was observed between both grafts. Before graft implantation, thrombin activities in Grafts I and II were 0.711 +/- 0.086 and 0.009 +/- 0.007 optical density at 405 nm, respectively. Thrombin activity of Graft II was significantly less than that of Graft I in every period after graft implantation, and platelet deposition of Graft II was significantly less than that of Graft I until POD 30. Thrombin-free fibrin-coated vascular prostheses have superior performance of antithrombogenicity to conventional fibrin-coated vascular prostheses with thrombin.

Animals↗
PubMed1999

Clinical experiences of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw: a 5-year follow-up study.

BACKGROUND: Titanium frameworks have been used in the endentulous implant patient for the last 10 years. However, knowledge of titanium frameworks for the partially dentate patient is limited. PURPOSE: To report the 5-year clinical performance of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw. MATERIALS AND METHODS: A consecutive group of 383 partially edentulous patients were, on a routine basis, provided with fixed partial prostheses supported by Brånemark implants in the mandible or maxilla. Besides conventional frameworks in cast gold alloy, 58 patients were provided with titanium frameworks with three different veneering techniques, and clinical and radiographic 5-year data were collected for this group. RESULTS: The overall cumulative survival rate was 95.6% for titanium-framework prostheses and 93.6% for implants. Average bone loss during the follow-up period was 0.4 mm. The most common complications were minor veneering fractures. Loose and fractured implant screw components were fewer than 2%. An observation was that patients on medications for cardiovascular problems may lose more implants than others (p < .05). CONCLUSIONS: The clinical performance of prostheses with implant-supported laser-welded titanium frameworks was similar to that reported for conventional cast frames in partially edentulous jaws. Low-fusing porcelain veneers also showed clinical performance comparable to that reported for conventional porcelain-fused-to-metal techniques.

Adult↗