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PubMed1977

Long-term survival after tricuspid valve replacement. Results with seven different prostheses.

The experience with tricuspid valve replacement (TVR) with seven different prostheses, alone or combined with replacement of other valves, in 73 patients (64 rheumatic and nine nonrheumatic) between 1964 and March, 1975, at the University of Alberta Hospital has been reviewed. Early and late mortality rates in rheumatic patients were 41 and 23 percent, respectively (36 percent being alive after a mean of 5.6 years), compared to 33 and 11 percent, respectively, in the nonrheumatic patients (56 percent being alive after a mean of 2 years). Of all survivors, 88 percent were functionally improved. Among the rheumatic patients: (1) 88 percent had organic tricuspid disease; (2) of the 39 patients with tricuspid insufficiency who underwent corrective mitral surgery 7 years before TVR, the tricuspid insufficiency had progressed over the 7 years; (3) the number of patients with tricuspid insufficiency had increased (39 versus 59) over the same 7 year period; (4) a high early mortality rate was encountered in those who were preoperatively in New York Heart Association (N.Y.H.A.) Class IV, or who had cardiomegaly, or pulmonary hypertension, or poor ventricular function, or organic disease, or reoperation; (5) the percentages of survivors with different prostheses were: Starr-Edwards, 31 percent; Beall-Surgitool, 14 percent; Kay-Shiley, 46 percent, Björk-Shiley, 50 percent; Lillehei-Kaster, 100 percent; Cutter-Smeloff and Wada-Cutter, nil. Among the nonrheumatic patients, two with the Cutter-Smeloff, two with the Beall-Surgitool, and one with the Lillehei-Kaster were alive after 14, 37, and 15 months, respectively. Among all survivors of TVR, late thrombus and pannus developed on both ball and disc prostheses (Starr-Edwards, two; Cutter-Smeloff, one; Lillehei-Kaster, one). These findings suggest that TVR should be performed earlier in rheumatic patients to reduce the operative mortality rate and that the Lillehei-Kaster prosthesis is probably most suitable for TVR.

Adolescent↗
PubMed1992

The effects of aortic reconstruction and collagen impregnation of Dacron prostheses on the complement system.

Complement activation has been associated with numerous clinical hazards such as platelet aggregation, adult respiratory distress syndrome, and renal dysfunction. The complement system is activated by exposure of different biomaterials to blood. Recently a watertight knitted Dacron aortic prosthesis impregnated with bovine collagen has been developed. One potential disadvantage is that this bovine collagen may activate the complement system and evoke the production of inflammatory mediators. We conducted a prospective randomized trial to study the systemic effects of collagen-impregnated prostheses and of aortic surgery with implantation of Dacron prosthesis on the complement system in the perioperative period and at 3 months after operation. Forty-one patients randomly received either a collagen-impregnated (n = 20) or a nonimpregnated prosthesis (n = 21). Twelve patients who had cholecystectomy served as controls. CH50 consumption and C3a generation were determined to study overall complement activation. Furthermore, C3a/C3 fractions were calculated. Finally, C4 and factor B consumption were determined to evaluate the complement stimulation via the classic and the alternative pathways, respectively. We found significant activation of the complement system during the operation in both the collagen group (CH50 consumption: 40%, p = 0.03; C4 consumption: 74%, p < 0.0001; factor B consumption: 73%, p < 0.0001; C3a/C3 fraction increase: 173%,p = 0.04), and the nonimpregnated group (CH50 consumption: 40%, p < 0.0001; C4 consumption: 71%, p < 0.0001; factor B consumption: 76%, p < 0.0001; C3a/C3 fraction increase: 165%, p = 0.025), with no statistically significant differences between the groups of prostheses. Activation was initiated via both the classic and the alternative pathway. This indicates aortic implantation significantly activates the complement system, but that collagen-impregnated prostheses do not stimulate the complement system any more than its nonsealed substrate. Comparing results in patients with vascular disease with controls, a significantly increased complement activation was observed in the vascular group (CH50 consumption: 40%, p < 0.0001; C4 consumption: 74%, p < 0.0001; factor B consumption: 75%, p < 0.0001; C3a/C3 fraction: 169%, p = 0.002), compared with the controls (CH50 consumption: 71%; C4 consumption: 104%; factor B consumption: 94%; C3a/C3 fraction: 119%, all p = NS), with statistical significant differences between the vascular group and cholecystectomies (CH50: p = 0.005; C4: p = 0.002; factor B: p < 0.0001, and C3a/C3 fraction: NS). This observation demonstrates that aortic surgery with the implantation of a Dacron prosthesis significantly activates the complement system.

Adult↗
PubMed1992

Mechanisms of failure of modular prostheses.

The expectations of wear and longevity of total hip components are based in large part on Charnley's early work. The evolution of the total hip from the one-piece, all-polyethylene acetabular component and fixed-head femoral component to the myriad of parts that comprise many of today's total hip designs has brought with it an array of potential mechanisms for failure that were not present in the earlier design. The risk/benefit ratio of these new designs may need to be reevaluated based on the additional mechanisms for failure that they provide. One hundred eleven acetabular hip prostheses and 139 femoral prostheses, all of modular configuration, retrieved by surgeons in the field, and sent for histologic examination, were analyzed for this study. A number of component characteristics were found to be correlated to early failure. These included acetabular designs with thin polyethylene bearings, poor fixation of the polyethylene to the metal shell, and geometries that permitted a moment to be applied to the bearing insert, tending to cause it to rotate in the metal shell. Modular femoral components were observed to be susceptible to corrosion, with titanium-alloy stems mated to cast cobalt-alloy heads at greatest risk attributable to a galvanic effect. All modular connections of femoral and acetabular components are at risk for disassociation and fretting; therefore, clever design and precision machining are necessary to produce prostheses in which the benefits of modularity exceed the risks.

Acetabulum↗
PubMed2003

External breast prostheses: misinformation and false beliefs.

This article discusses common myths associated with the use of external breast prostheses and the impact this misinformation may have on the quality of life of women after mastectomy. A review of the literature reveals that very little research has been conducted on this subject. The majority of information on breast prostheses is provided by the manufacturers and tacitly accepted by healthcare providers and the media in general. Claims regarding the medical necessity of a weighted prosthesis and the suitability of gel fillings are examined and found wanting. Widespread acceptance of these myths may be preventing women from pursuing healthy lifestyle options and restricting the development of more suitable prosthetic products. The article concludes that a rigorous, evidence-based approach to the evaluation of external breast prostheses would enhance both the development of this noninvasive and cost-effective sector of post-mastectomy care, as well as the adjustment, well being and quality of life of breast cancer survivors.

Body Image↗
PubMed1992

Rapid endothelialization of vascular prostheses by seeding autologous venous tissue fragments.

A method was developed to obtain rapid endothelialization of a fabric vascular prosthesis by seeding autologous venous tissue fragments into its wall. In an animal study, complete endothelialization was observed in the entire inner surface of the prosthesis within 2 weeks after implantation. A piece of peripheral vein was minced with scissors and then stirred into saline to create a tissue suspension. This suspension was enmeshed into the wall of a highly porous fabric vascular prosthesis by repeated pressurized injections with a syringe. The prostheses (7 mm inside diameter and 5.7 cm in length), seeded with tissue fragments, were implanted into the descending thoracic aorta of 25 dogs, and they were removed from 1 hour to 2 months after implantation. Twenty-five prostheses, preclotted with fresh blood, were used as control prostheses. In the seeded graft, a thin fibrin layer covered the inner surface just after implantation, but countless numbers of endothelial cells migrated from the fragments and came up to the luminal surface like multiple "mushrooms" under the fibrin layer. Smooth muscle cells made multiple layers underneath the endothelial cell layer. The healing proceeded equally at every part. By this active migration and proliferation, the inner surface was completely healed within 2 weeks.

Animals↗
PubMed2004

[Experiment and study of endothelialization of prostheses with bone marrow CD34+ cells].

OBJECTIVE: To exploration the endothelialization of prostheses with bone marrow CD(34)(+) cells. METHODS: CD(34)(+) cells were isolated from bone marrow of carine by an immune magnetic cell sorting system and induced into endothelial cells with VEGF. Seeding the cells to PTFE prostheses which implanted the abdominal aorta artery (AAA) and inferior vena cava (IVC). RESULTS: The isolated cells from bone marrow were CD(34)(+) by flow cytometer which could differentiate into endothelial cells in vascular endothelial growth factor (VEGF). The endothelial cells were identified by immunostaining and transmission electron microscope. The obliteration rate of the seeding grafts implanting AAA was 0%, the stenosis rate 12.5%; the obliteration rate implanting IVC 12.5%, the stenosis rate 25%. CONCLUSION: CD(34)(+) cells were isolated from bone marrow by an immune magnetic cell sorting system and were able to be induced into endothelial cells with VEGF in vitro. PTFE prostheses seeding CD(34)(+) cells have the ideal endothelialization and patency.

Animals↗
PubMed2004

Aortic valve replacement with 31- and 33-mm mechanical prostheses: early results.

The mean aortic diameter of Indian adults is 25-31 mm, yet fewer than 1% of worldwide heart valve procedures involve a 31-mm aortic heart valve. Of the 72 large prosthetic aortic valves (31-mm) implanted in the Asia Pacific region during 2001-2003, 53 (74%) were implanted at our institution. This retrospective study was undertaken to assess early results and outcomes, on echocardiography and exercise testing, in patients who received large prosthetic aortic valves. From January 1997 through December 2002, 27 patients underwent isolated aortic valve replacement with 31-mm St. Jude Medical prostheses, and 4 patients underwent aortic valve replacement with 33-mm St. Jude Medical reversed mitral prostheses. These 31 patients were among 240 who underwent isolated aortic valve replacement at our institution during the same period. The preoperative, perioperative, and postoperative data were collected from case records and patient follow-up. Fifteen of the 31 patients underwent echocardiography and exercise testing at least 6 months after operation. There were no early deaths. No patient developed prosthetic valve endocarditis or paravalvular leak. One patient, who developed valve thrombosis as a result of noncompliance with the anticoagulation regimen, underwent thrombectomy and died during the early postoperative period, due to low cardiac output. There was no structural failure or anticoagulant-related hemorrhage. Postoperatively, the peak and mean gradients across the prostheses were low. The exercise performance of all the patients was good. These early favorable results need to be borne out by longer and more comprehensive study of larger groups.

Adolescent↗
PubMed2004

Wear properties of alumina/zirconia composite ceramics for joint prostheses measured with an end-face apparatus.

While only alumina is applied to all-ceramic joint prostheses at present, a stronger ceramic is required to prevent fracture and chipping due to impingement and stress concentration. Zirconia could be a potential substitute for alumina because it has high strength and fracture toughness. However, the wear of zirconia/zirconia combination is too high for clinical use. Although some investigations on composite ceramics revealed that mixing of different ceramics was able to improve the mechanical properties of ceramics, there are few reports about wear properties of composite ceramics for joint prosthesis. Since acetabular cup and femoral head of artificial hip joint are finished precisely, they indicate high geometric conformity. Therefore, wear test under flat contact was carried out with an end-face wear testing apparatus for four kinds of ceramics: alumina monolith, zirconia monolith, alumina-based composite ceramic, and zirconia based composite ceramic. Mean contact pressure was 10 MPa and sliding velocity was 40 mm/s. The wear test continued for 72 hours and total sliding distance was 10 km. After the test, the wear factor was calculated. Worn surfaces were observed with a scanning electron micrograph (SEM). The results of this wear test show that the wear factors of the both composite ceramics are similarly low and their mechanical properties are much better than those of the alumina monolith and the zirconia monolith. According to these results, it is predicted that joint prostheses of the composite ceramics are safer against break down and have longer lifetime compared with alumina/alumina joint prostheses.

Aluminum Oxide↗
PubMed2004

Ten-year outcome with the sorin bicarbon and Baxter Mira bileaflet prostheses in the aortic position.

BACKGROUND AND AIM OF THE STUDY: Sorin Bicarbon (SB) and Baxter Mira (BM) are almost identical bileaflet prostheses that share the same mechanical design, the only difference being in the sewing cuff. Hence, the long-term clinical performance of the two prostheses, when implanted in the aortic position, was evaluated in a combined population of patients. METHODS: Between January 1992 and December 2002, 714 patients (454 males, 260 females; mean age 60 +/- 13 years) underwent single aortic valve replacement with SB (n = 392) or BM (n = 322) valves. Concomitant non-valve procedures were performed in 64 patients (9.5%). Follow up was 95.7% complete, with a mean of 3.1 +/- 2.4 years. RESULTS: Operative mortality was 5.4% (39/714). Overall patient survival at five and 10 years was 89.3 +/- 1.4% and 77.7 +/- 4.3%, respectively; the linearized rate was 3.37% per pt-yr. Overall freedoms from complications at 10 years and valve group freedoms at four years were: thromboembolism 92.9 +/- 3.6% (SB 96.8 +/- 1.2% versus BM 98.4 +/- 0.8%); bleeding 94.5 +/- 3.5% (SB 97.5 +/- 1.1% versus BM 98.5 +/- 0.5%); nonstructural dysfunction 85.8 +/- 7.5% (SB 97.1 +/- 1.2% versus BM 99.3 +/- 0.07%); endocarditis 98.0 +/- 1.2% (SB 98.6 +/- 0.9% versus BM 100%); reoperation 95.1 +/- 3% (SB 98.6 +/- 0.9% versus BM 100%). Neither structural dysfunction nor valve thrombosis were observed. At the end of follow up, 78.3% of survivors were in NYHA class I, 17.3% in class II, 3.6% in class III, and 0.8% in class IV. CONCLUSION: Experience with Sorin Bicarbon and Baxter Mira valve prostheses shows that these valves, when implanted in the aortic position, provide a satisfactory clinical performance, with low complication rates.

Aged↗
PubMedDate not supplied

Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients.

PURPOSE: The study's aim was to report long-term costs in edentulous patients treated with mandibular implant-supported prostheses. MATERIALS AND METHODS: Ninety patients were divided into four groups based on the type of implant prosthesis (fixed or overdenture) and treatment year. Records were obtained from dental charts, and an economic analysis from the patient's perspective was conducted. Clinical time associated with various procedures was measured and applied to the four groups. Salary rates by age, occupation, and gender were used to value patients' time. Direct clinical and time costs over 10 years were converted to 2002 Canadian dollars using the Consumer Price Index and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was carried out to test the robustness of the time costs. RESULTS: Initial treatment and maintenance costs over the observation period were significantly higher for fixed compared to overdenture prostheses. A significant improvement in maintenance costs for the first patient group treated with fixed prostheses was observed over the follow-up period. Longer term (15 years) treatment costs for the initial two groups were significantly higher for the fixed group. The sensitivity analysis at an equal salary rate demonstrated the same trend: Time costs were significantly higher for the fixed groups. CONCLUSION: Long-term treatment costs indicated that the mandibular overdenture was a less expensive treatment compared to the fixed implant prosthesis.

Age Factors↗
PubMed2005

[Antibiotic prophylaxis for late blood-borne infections of joint prostheses].

By analogy with endocarditis prophylaxis, patients with joint prostheses are often given antibiotics before invasive procedures or dental treatment. However, this analogy is not justified: The pathogenesis and bacterial spectrum of infections of artificial joints differ from those of endocarditis. Since the efficacy of administering prophylactic antibiotics to patients with joint prostheses has never been scientifically proven, there is no general indication for such prophylaxis. On the other hand, infections in other parts of the body should be actively sought and treated promptly. Prophylactic antibiotic administration may be appropriate in individual cases during a procedure in patients who are at increased risk of a haematogenic prosthesis infection as a result of bacteraemia. For operations routinely performed under perioperative antibiotic cover, the same prophylaxis should also be used for patients with joint prostheses.

Antibiotic Prophylaxis↗
PubMed1979

[Laboratory methods of examination of porous vascular prostheses].

The author discusses applied methods of investigation of porous vascular prostheses with special attention to physical methods and proposes some heretofore unused criteria for the evaluation of polyester prostheses such as: quantitative determination of oligomers catalist residues, inor ganic fillers and manufacturer's oil and identification of the degree of crystallization and molecular orientation. The evaluation of these parameters in conjunction with the results of physical, mechanical, hematological, toxicologic and preclinical testing may form the basis for further improvement of vascular prostheses.

Biomechanical Phenomena↗
PubMed2005

[Breast reconstruction with expander prostheses].

Breast reconstruction with tissue expanders is a technique that has been known to clinical practice since 1978. The authors present their clinical experience in the Plastic and Reconstructive Surgery Service of the Virgen del Camino Hospital from 1980 to 2005. They describe breast reconstruction using tissue expanders and the evolution towards immediate breast reconstruction with durable expanders prostheses, which resemble conventional breast prostheses and try to emulate the extirpated breast. They provide an historical review of the repercussion of mastectomy and breast reconstructive surgery in the different professional and social areas, as well as the change in mentality of society and health professionals that has benefited patients. The characteristics of post-mastectomy breast reconstruction, using expanders prostheses, are set out, as well as its advantages and drawbacks.

Breast Implantation↗
PubMed1992

Complications of intracavernous injections and penile prostheses in spinal cord injured men.

Erectile dysfunction is a common complication in men who have had spinal cord injury (SCI). This retrospective study focuses on the complications encountered at our institution with both penile prostheses and intracavernous injections in men with SCI. Seventy-two men with SCI were treated with intracavernous injections for erectile dysfunction, and 30 penile prostheses were implanted in 19 men with SCI. Twenty-two of the 72 patients in the intracavernous injection program had adverse effects; none were severe. Prolonged erections lasting four to six hours and ecchymosis were the most common complications. No complication required discontinuation of treatment. There were 23 inflatable prostheses and seven semirigid rods. Mechanical failures occurred in 15 instances, infection occurred in nine, and late erosion occurred in three. Although multiple revisions and replacements were necessary, 14 of the 19 patients had satisfactorily functioning implants at their last outpatient visit. Patients were selected carefully for penile implant placement and yet significant complications and expense were incurred to obtain satisfactory results. Although follow-up has been relatively short, the intracavernous injections of vasoactive medications appear to be a more attractive initial means of treating the erectile dysfunction in men with SCI. The complications are relatively minor and the incidence of prolonged erections has decreased with increased experience. Furthermore, the cost of treatment will be considerably less than that with implant surgery, particularly in view of the high drop-out rate. Although improved implants have decreased the occurrences of mechanical failure, it seems likely that infection and extrusion will continue to be significant problems among men with SCI.

Adult↗
PubMed2005

[Shoulder prostheses: facts and perspectives].

The goals of shoulder arthroplasties are: 1) to decrease the pain associated with degenerative diseases of the glenohumeral joint and 2) to increase the shoulder mobility. Isolated humeral hemiprostheses are indicated for pathology limited to the humeral head (fractures, avascular osteonecrosis of the humeral head). Anatomical total shoulder prostheses are proposed in cases of diseases involving both parts of the glenohumeral joint (osteoarthritis, inflammatory arthritis). Reversed total shoulder prostheses (constraint) are reserved for glenohumeral arthropathies associated with extensive lesions of the rotator cuff. The main complications include the glenoid loosening (total prostheses) and the secondary glenoid wear (hemiprostheses).

Arthroplasty, Replacement↗
PubMed2005

[The effect of polyester vascular prostheses on synthesis TNF-alpha, IFN-gamma and NO by human peripheral blood leukocytes--in vitro].

Vascular prostheses produced on the basis of polyester are today commonly used in vascular surgery. To improve their biofuncionality special technologies are used, among them double knit and hydrophile feature enrichment. These modifications could cause the local activation of leukocytes to produce the mediators of inflammatory reaction, which in turn leads to hyperplasia of endothelium and other dangerous complications. In our study we used two kinds of polyester prostheses: double velour knitted hydrophilic Dallon H and standard double velour knitted prosthesis Dallon as control. The aim of this work was to compare in vitro the levels of cytokines TNF-alpha, interferon (IFN) and nitric oxide (NO) found in the supernatants of human blood leukocyte cultures after stimulation by both these above-mentioned vascular prostheses materials which are designed for use in direct blood contact. Tested implant materials Dallon H had no influence on synthesis of production of IFN, TNF-alpha and NO by human blood leukocytes. These results allow to made the initial selection of biomaterials before their in vivo evaluation.

Biocompatible Materials↗
PubMedDate not supplied

Outcomes of fixed prostheses supported by immediately loaded endosseous implants.

PURPOSE: The aim of this article was to evaluate the survival and success of Straumann implants after immediate loading. A new method for fabricating effective definitive prostheses to immediately load implants in edentulous patients was presented. MATERIALS AND METHODS: Nine patients received 4 implants each, and resin-metal prostheses were installed less than 48 hours after implant placement. Mobility was evaluated immediately after the surgical procedures and 3 months subsequently using the Periotest. Clinical evaluation of soft peri-implant tissues was conducted monthly after the sutures were removed, and radiographs were obtained 6, 12, and 24 months after the surgery. RESULTS: The Periotest revealed statistical values that were stable, with no mobility. No signs of inflammation and/or bleeding were observed. The radiographs did not reveal any continuous areas of radiolucency beyond the first thread of the 36 implants after 24 months. None of them failed, and the success rate was 100%. DISCUSSION: It is possible to submit implants to immediate load without jeopardizing osseointegration if parameters are met, such as suitable bone quality and quantity, lack of unfavorable systemic and psychologic factors, lack of parafunctional habits, strict maintenance of prosthetic requirements, minimization of micromotion, and use of an appropriate surgical protocol. CONCLUSION: Under immediate load, osseointegration of implants is possible, and the method presented for the fabrication of resin-metal prostheses has been reliable and predictable.

Adult↗
PubMedDate not supplied

Influence of implant and conventional prostheses on satisfaction and quality of life: A literature review. Part 2: Qualitative analysis and evaluation of the studies.

PURPOSE: To review the influence of prosthodontic and dental implant treatment on patient satisfaction and oral health-related quality of life (OHQOL) based on a systematic search of the literature. MATERIALS AND METHODS: A systematic literature search was carried out for articles published between 1960 and February 2003. Details of the search process and results were reported in Part 1 of the study (Int J Prosthodont2004;17:83-93). The included studies were categorized and evaluated according to their level of evidence, following the guidelines of the Agency for Health Care Policy and Research. The characteristics and content of the studies were analyzed and tabulated. RESULTS: Among the 114 included studies, there were 76 publications reaching evidence level III. The results showed that the effects of compromised oral health are not limited to traditional clinical aspects, but can considerably affect patients in various activities of daily life. Twenty-four of the 38 investigations with evidence levels I and II dealt with implant stabilization of complete mandibular prostheses, comparing implant prostheses to conventional complete dentures. Fully edentulous patients experience negative impacts on OHQOL from their condition. They benefit significantly from the use of dental implants to support mandibular prostheses. However, support by more than 2 implants does not appear to further significantly increase patient satisfaction and OHQOL. CONCLUSIONS: To date, research in the field of patient-based outcomes has concentrated on dental implant treatment for the edentulous patient. Other prosthetic treatments such as single crowns, fixed and removable partial dentures, or further treatment concepts (eg, the shortened dental arch concept) are not well represented. The use of patient-centered outcome measures can help to find an individual, patient-oriented prosthetic solution.

Activities of Daily Living↗