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PubMed1993

Nickel sensitivity and the implantation of orthopaedic prostheses.

There is no evidence that nickel-sensitive patients, when given a modern plastic-to-stainless-steel hip replacement, develop cutaneous reactions or loosening of their prostheses. However, eczema is occasionally seen with static metal prostheses and eruptions sometimes accompanied the use of the older types of joint prosthesis. Modern plastic-to-metal joint replacements rarely cause sensitization to the composite metals. In the rare instances when this has been detected by patch testing, the affected patients have not developed eczema or loosening of their prostheses.

Dermatitis, Allergic Contact↗

PubMed2004

Considerations on surface and structural biocompatibility as prerequisite for long-term stability of neural prostheses.

Neural prostheses are technical systems that partially substitute neural functions of the body after traumatic lesions or neurological disorders. Using biomedical microsystems, complex implants can be designed and fabricated in very small dimensions. However, miniaturization of neural prostheses for long-term implantation is very challenging. Implants not only have to be biosafe and biostable in terms of cytotoxicity and degradation, they also have to cope with the biological requirements of structural biocompatibility. In this paper, examples of biomedical microimplants for neural prostheses use are introduced. Results from basic biocompatibility investigations regarding the cytotoxicity are reported, as well as aspects of the interaction between surface structure and cell behaviour. A detailed outlook addresses possible approaches to use nanosciences to ensure long-term stability of thin technical layers within the body and create surfaces for selective and specified functional reactions at the interface between the artificial implant and the biological environment.

Biocompatible Materials↗

PubMed2003

The potential for bronchoscopic lung volume reduction using bronchial prostheses: a pilot study.

STUDY OBJECTIVES: Significant morbidity and mortality offset the benefits of lung volume reduction surgery (LVRS) for emphysema. By contributing to distal lung collapse, bronchoscopic placement of valved prostheses has the potential to noninvasively replicate the beneficial effects of LVRS. The purpose of this study was to investigate the safety and feasibility of placing valves in segmental airways of patients with emphysema. DESIGN: Case series. SETTING: Tertiary hospital, severe airways disease clinic. PATIENTS: Ten patients aged 51 to 69 years with apical emphysema and hyperinflation, otherwise suitable for standard LVRS. Mean preoperative FEV(1) was 0.72 L (19 to 46% predicted), and 6-min walk distance was 340 m (range, 245 to 425 m). INTERVENTION: Apical, bronchoscopic, segmental airway placement of one-way valves (silicone-based Nitinol bronchial stent; Emphasys Medical; Redwood City, CA) under general anesthesia. Placement was over a guidewire under bronchoscopic and fluoroscopic control. RESULTS: Four to 11 prostheses per patient took 52 to 137 min to obstruct upper-lobe segments bilaterally. Inpatient stay was 1 to 8 days. No major complications were seen in the 30-day study period. Minor complications included exacerbation of COPD (n = 3), asymptomatic localized pneumothorax (n = 1), and lower-lobe pneumonia (day 37; n = 1). Symptomatic improvement was noted in four patients. No major change in radiologic findings, lung function, or 6-min walk distance was evident at 1 month, although gas transfer improved from 7.47 +/- 2.0 to 8.26 +/- 2.6 mL/min/mm Hg (p = 0.04) and nuclear upper-lobe perfusion fell from 32 +/- 10 to 27 +/- 9% (mean +/- SD) [p = 0.02]. CONCLUSION: Bronchoscopic prostheses can be safely and reliably placed into the human lung. Further study is needed to explore patient characteristics that determine symptomatic efficacy in a larger patient cohort.

Aged↗

PubMed1991

Equipment and methods for laboratory testing of ankle-foot prostheses as exemplified by the Jaipur foot.

A load deflection and a cyclic loading apparatus capable of measuring dorsiflexion/plantarflexion, pronation/supination, internal/external rotation, and cyclic dorsiflexion (60 cycles per minute) of ankle-foot prostheses are described. A test protocol was developed to assess the functional parameters of the Jaipur ankle-foot prosthesis before and after prolonged cyclic loading, with the simultaneous aim of evaluating these machines. The results on 26 Jaipur ankle-foot prostheses revealed that: 1) the prosthesis enjoys considerable mobility in three planes, confirming its known versatility; 2) the prosthesis is robust; and, 3) the testing machines deliver reproducible results and are suitable for in-house testing of ankle-foot prostheses.

Amputation, Surgical↗

PubMed1992

History of prostheses and orthoses in Japan.

Until the first contact with European civilization in 1543, prostheses and orthoses were not seen in Japanese medical history. Some physicians and surgeons who studied medicine in the Dutch language understood about prostheses and orthoses before the opening of the country in 1868. From 1868 to the end of World War II (1945), prostheses and orthoses were influenced by German orthopaedic surgery. From the latter half of the 1960s the research and development of these have been advanced, because of the establishment of a domestic rehabilitation system, international cultural exchange and economic development.

History, 16th Century↗

PubMedDate not supplied

Myoelectric prostheses for below-elbow amputees: the Trent experience.

Experience of myoelectric prostheses for unilateral below-elbow amputees in a large region of Great Britain is presented. Of the cases considered, 14 were adults and 29 were 16 years of age or less. The rejection rate was 25% overall but it was lower in adults, at 17%. Comparisons with published data and other aspects of myoelectric prostheses are discussed. Just over half the 37 amputees interviewed were independent in activities of daily living; independence was more common in the adults, at 77%. A very large proportion of myoelectric prosthesis users also used body-powered prostheses, demonstrating a need for both types of prosthesis for optimum rehabilitation. It is recommended that myoelectric prosthetic programmes should be carried out from specialized centres with comprehensive facilities for this expensive rehabilitation aid.

Activities of Daily Living↗

PubMed1994

Initial mechanical stability of acetabular prostheses.

Secure initial stability is crucial for prostheses designed for biological ingrowth; without it, subsequent tissue ingrowth is impossible. Mechanical testing was performed in vitro to measure the interface shear stability of acetabular cup prostheses. Cemented, threaded, fined, and press-fit cups, both with and without supplemental screw fixation, were tested. A mechanically consistent polyethylene foam was used as a substrate to obviate the variations inherent in cadaver bones. Ramped, eccentric rim loads were applied using a servohydraulic materials testing system. Reaming, insertion, and loading variables were carefully controlled. Cups with external threads were significantly more stable than those fixed by fins or screws. Press-fit cups were significantly looser than all other tested designs. None of the uncemented prostheses approached the initial stability of cups secured with acrylic bone cement.

Acetabulum↗

PubMed2000

Peri-implant soft tissue maintenance in patients with craniofacial implant retained prostheses.

The aim of this pilot study was to describe the effectiveness of a hygiene protocol prescribed for patients receiving craniofacial implant retained prostheses. Eleven subjects receiving either orbital or auricular prostheses were instructed by a hygienist in debris removal procedures. Patients were re-examined on at least four occasions over the following 18 months, and tissue health around the implant abutments was evaluated using standard criteria. In most cases, adequate debris removal was demonstrated, particularly when hygiene procedures were reinforced at the second follow-up visit. Barriers to maintenance of tissue health included inadequate space between fixtures and thickness of skin around abutments. Occasionally, prostheses had to be replaced due to inappropriate cleaning methods. The intensive hygiene regimen helped maintain tissue health around implant abutments, although it was demanding in terms of professional time.

Adult↗

PubMed2000

Facial prosthetics: techniques used in the retention of prostheses following ablative cancer surgery or trauma and for congenital defects.

The retention of facial prostheses is a major factor influencing the successful outcome of rehabilitative treatment following ablative cancer surgery or trauma and for the prosthetic replacement of congenitally absent tissue. Since the sixteenth century to the present day, facial prosthetic devices have been retained by methods including adhesives and spectacle frames. The introduction of the Branemark extra oral implant system enhanced the stability of life-like prostheses thus giving patients more confidence in their use. This paper outlines the retention systems commonly used at the authors unit and the benefits gained by the use of implants to retain facial prostheses. The use of a single stage surgical technique instead of the usual two stage procedure is detailed.

Adolescent↗

PubMed2001

Esthetic prostheses in minor and major upper limb amputations.

In summary, the impact and value of esthetic prostheses on amputee rehabilitation and their long-term use were demonstrated in this study to have no correlation with the severity of injury and level of amputation. All patients with traumatic amputation should be given equal opportunity to receive prostheses if the service is readily available. Whether use of prostheses is temporary or long-term, they help patients cope with the traumatic life experience of limb loss.

Amputation, Traumatic↗

PubMed1989

[Cancer of the breast and breast prostheses].

Plastic surgery operations designed to modify the breast volume do not increase the risk of cancer. Xeroradiography provides the best images of operated breasts. The least interfering prostheses are the most radiolucent and, in particular, retropectoral prostheses. The diagnosis of cancer is based on the detection of microcalcifications and star-shaped images. It is guided by clinical examination which is precise as the content of the breast is thin an lies on top of the anterior surface of the implant. The complications of prostheses (shells, collapse, rupture, displacement) have been well studied. After breast reconstruction examination of the contralateral breast is therefore of prime importance due to the risk of bilateral cancer.

Breast↗

PubMed1989

The Flexi-Flate and Flexi-Flate II penile prostheses.

Our experience with 45 recipients of the Flexi-Flate and Flexi-Flate II prostheses leads us to the following conclusions: 1. The device is readily implantable in approximately 1 hour with techniques familiar to most urologists who have implanted rigid or semirigid rods. 2. With attention to detail, prosthesis sizing is straightforward using intraoperative determination of corporeal girth and total corporeal length. We were unable reliably to predict prosthesis size preoperatively. Hence, as with other inflatable prostheses, we recommend that an entire range of prosthesis sizes be available at implantation. 3. Mechanical reliability is similar to that of more complex inflatable devices. The mechanical malfunction rate has been 11.6 per cent over a 15.1-month follow-up. 4. Patients find the inflation-deflation mechanisms easy to master. 5. Spontaneous deflation does occur during intercourse in some instances, but most patients are able to adjust sexual techniques and position satisfactorily with minimal disruption of enjoyment for themselves and their partners. 6. Among individuals with functional prostheses, a detailed survey of patient and partner response postoperatively revealed a high level of satisfaction for both and a return to premorbid levels of sexual functioning. Concealability was good in the flaccid state, and patients report minimal difficulties or embarassment with everyday functions in public restrooms and shower situations.

Consumer Behavior↗

PubMedDate not supplied

Perigraft-reaction after implantation of vascular prostheses. Pathogenesis, clinical picture and treatment.

This report is based on 18 perigraft reactions in 2237 implanted vascular prostheses (1970-1985). The incidence of this complication is 6.8-9.5/1000 both for Dacron-double-velour and expanded PTFE-prostheses. The clinical picture is characterized by localized or extended fluid accumulation around the artificial graft (perigraft cysts or "swimming prosthesis"). Including 271 reports from the literature, 75% of vascular prostheses in extraanatomical positions were affected. The time interval between vascular substitution and clinical manifestation is on average 23.5 months. The pathogenesis of this aseptic late complication is still unclear. Several disposing factors are under discussion: (a) physico-chemical irritation of the surrounding tissue by the fabric itself (release of monomers, emulgators etc.), (b) mechanical trauma (continuous movement of the graft in the tissue bed, i.e. insufficient tissue fixation resulting in gaps and exudation of fluid round the prosthesis), (c) latent or manifest renal insufficiency. The partial or total removal of the affected prosthesis and its substitution by another type of vascular prosthesis offers the best chance of definitive cure. Repeated puncture of perigraft cysts produces frequent recurrencies and the danger of secondary infections. Therefore only an exchange of the graft can be recommended.

Aged↗

PubMed1987

A study of the bone-cement interface in upper limb prostheses not subjected to loading.

The appearance of a radiolucent band at the cement-bone interface is a frequent finding in lower limb prostheses. This is still a controversial subject, but almost certainly has a multifactorial basis. Stress related to loading may be one of the causal factors. The authors therefore studied the evolution and behaviour of this radiolucent line at the bone-cement interface in 31 upper limb prostheses not subjected to significant loading or stress. These were special prostheses designed to replace the upper humerus after the radical excision of bone tumours. The development of a radiolucent band was not significantly different from the usual conditions in which loading is present but in our cases it was nonprogressive and there was never any evidence of loosening of the prosthesis.

Adult↗

PubMed1980

[The use of polypropylene-polyester prostheses in cranioplasty].

The polypropylene-polyester prostheses were investigated in respect of their usefulness in cranioplasty. Experiments were performed upon 2 to 10 years old mongrels. It was stated that polypropylene-polyester prostheses did not produce any general reactions. X-ray examinations did not show any evidences of pathological changes in cranial bones adjoining the prosthesis. Histological investigations revealed slight inflammation and moderate foreign body reaction caused by the operation. The prosthesis had good mechanical resistance and it was well fixed in the place of implantation. Mechanical resistance and good tolerance may be the basis for the use of the prostheses in clinical cases.

Animals↗

PubMed1981

Platelet changes after placement of aortic prostheses in dogs. II. Impaired surface-induced arterial thrombosis.

An experimental preparation was developed to assess changes in surface-induced arterial thrombosis in nine dogs with woven Dacron aortic prostheses. The preparation consisted in measuring the occlusion time of an A-V shunt with controlled flow rate (200 mg/min). This measurement depended on formation of an occlusive, platelet-rich thrombus on a diaphragm of polyester mesh. Two to 6 months after placement of thoracoabdominal aortic prostheses, all animals demonstrated striking prolongation of A-V shung occlusion time. This occurred in the presence and absence of heparin anticoagulation. No change in A-V shunt occlusion time was noted in dogs who had sham operations. These findings complement out studies showing biochemical and functional changes in circulating platelets in dogs with aortic prostheses, and together they are consistent with mild platelet damage sufficient to impair surface-induced thrombosis. They also support our contention than, in dogs, platelets interact reversibly with prosthetic surfaces.

Animals↗

PubMed1995

Prostheses for stapes surgery.

A variety of different implants are available today for use by the otologic surgeon. All prostheses are well tolerated, and the risks of complication as a result of their implantation are comparable. The most commonly used prostheses are the wire-Teflon piston and the stainless steel bucket handle. Although the otologic surgeon has a wide variety of prostheses to choose from, most have a preference for one particular type. Results of hearing improvement following a successful stapedectomy is more a function of the surgeon's experience than of the type of prosthesis used. As James L. Sheehy, MD, so often says, "if a technique is working well for you, don't change for change's sake" (personal communication, 1994).

Ear Ossicles↗

PubMed1994

Histological assessment of fifty breast capsules from smooth and textured augmentation and reconstruction mammoplasty prostheses with emphasis on the role of synovial metaplasia.

Fifty breast capsules surrounding smooth and textured breast prostheses were reviewed histologically, immunohistochemically, and ultrastructurally, and findings correlated with patient data. The histology of the capsules varied; although most consisted of a simple fibrocollagenous membrane, some were lined by organized, round to polyhedral cells similar to synovium. Histologically, the lining of the synovial type consisted of epithelioid cells overlying parallel bands of collagen, with basally located nuclei and cytoplasmic processes directed toward the surface and arranged within a well developed reticulin network. Immunohistochemically, the cells were vimentin positive, weakly positive focally for alpha-1-antitrypsin, alpha-antichymotrypsin, and lysozyme, and negative for EMA and AE1/AE3. Scanning electron photomicrographs showed a bosselated luminal lining overlying parallel bands of collagen. By transmission electron microscopy, both secretory and phagocytic cells could be distinguished. Some of the former were multinucleated. No basement membrane material could be identified, and cell junctions were rare. Histologically, immunohistochemically, and ultrastructurally the lining appeared identical to synovium and to the synovial metaplasia that has been described in sutured skin, after repeated subcutaneous injections of air, the bone-cement interface of loose hip prostheses and adjacent to gliding silastic tendon reconstruction rods. The physical and chemical composition of the prostheses, the mechanical forces, and the developmental response of the host mesenchymal tissue are thought to influence the formation and maintenance of the synovial metaplasia of the breast capsule.

Breast↗