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As more extensive craniofacial resections for recurrent orbital and nasoethmoidal carcinoma are performed, the need for complex external prostheses increases. A new method of stabilization for large prostheses using osseointegrated implants is presented. This is illustrated in a typical patient who underwent a large naso-orbital maxillary resection for recurrent basal cell carcinoma.
Using a previously developed method for quantitative measurements of silicone concentrations in breast tissue, material from 86 biopsies from 67 breasts in 55 patients who had silicone implants was examined. In the 49 breast with unruptured prostheses, there was a positive relation between the concentrations and inflammatory reactions, the only exception being the amount of plasma cells, which showed a negative relation. It is concluded that silicone prostheses provoke an inflammatory response not only because they act as foreign bodies, but also because of silicone seepage through intact membranes.
Visual prostheses are based on neuronal electrical stimulation at different locations along the visual pathway (ie, cortical, optic nerve, epiretinal, subretinal). In terms of retinal prostheses, advances in microtechnology have allowed for the development of sophisticated, high-density integrated circuit devices that may be implanted either in the subretinal or epiretinal space. Analogous to the cochlear implants for some forms of deafness, these devices could restore useful vision by converting visual information into patterns of electrical stimulation that would excite the remaining spared inner retinal neurons in patients with diseases such as retinitis pigmentosa and age-related macular degeneration. The different types of implants and recent results are discussed, but special emphasis is given to retinal implants.
STUDY DESIGN: A study was conducted to investigate the biomechanical, histochemical, and biologic ingrowth characteristics of the most widely used total disc prosthesis, the hydroxyapatite-coated SB Charité prosthesis. OBJECTIVE: To compare the porous ingrowth, linear apposition, or bony ingrowth in total disc replacement with published reports of porous ingrowth prostheses in the appendicular skeleton. METHODS: Seven mature baboons (Papio cynocephalus) underwent L5-L6 total disc replacement through an anterior transperitoneal approach. The SB Charité prosthetic vertebral endplates (n = 14) were cobalt-chrome covered by two layers of thin titanium with a hydroxyapatite coating, which was electrochemically bonded to the implant surface. RESULTS: At 6 months after surgery, the range of motion exhibited by the SB Charité and the nonoperative control subjects under axial compression, flexion-extension, and lateral bending showed no statistical difference (P > 0.05). Plain film radiographic analysis showed no lucencies or loosening of any prosthetic vertebral endplate. Gross histopathologic analysis of the hydroxyapatite-coated SB Charité prosthesis demonstrated excellent ingrowth at the level of the implant-bone interface, without evidence of fibrous tissue or synovium. Histochemical assays showed no accumulation of particulate wear debris (no titanium, ultrahigh molecular weight polyethylene, or cobalt-chrome) nor cytokines (tumor necrosis factor-alpha, prostaglandin E2, interleukin-1, -2, or -6). Total endplate area showed a mean ingrowth (volume fraction) of 47.9% +/- 9.12% and a total ingrowth range of 35.5% to 58.8%. CONCLUSIONS: The porous ingrowth (percentage of pore ingrowth coverage at the bone-metal interface) was more favorable for total disc replacement than for cementless total joint components in the appendicular skeleton (range, 10-30%). The reason for the improved degree of porous ingrowth in total disc replacement prostheses probably is that ligamentotaxis causes sustained compression across the metal-bone interface.
STUDY DESIGN: This article is based on a comprehensive review of the literature related to intervertebral disc prostheses. OBJECTIVE: To compile an overview of the results and complications related to various types of lumbar and cervical disc replacements. SUMMARY OF BACKGROUND DATA: A functional disc prosthesis has been sought since the 1950s. Although there were a few early attempts, disc replacement did not become a viable therapy until the late 1980s. Devices that were used in Europe at that time are now being evaluated in the United States in clinical trials. Cervical disc replacements are currently in the early stages of development and evaluation. METHODS: A thorough literature search was conducted to identify articles published on intervertebral disc prostheses. Proceedings from conferences were reviewed as well. Articles were classified by topics, including lumbar total disc replacement, disc nucleus replacement, and cervical disc replacement. RESULTS: Results of total disc replacement are favorable, with 63-85% of patients having a good outcome. As with any procedure, issues related to patient selection, operative technique, and device size selection were learned from the early experiences with these devices. There has been only one disc nucleus replacement used in an appreciable number of patients. This has yielded good results, but there have been problems related to device displacement. There are increasing reports on the use of cervical disc replacements, but they are still in the early evaluation phases. However, as with the lumbar counterparts, new designs are being evaluated. DISCUSSION: Although still in the early phases of development, functional disc replacement will become a part of the spine surgeon's armamentarium for the treatment of patients with disc-related pain unresponsive to nonoperative care. The future in this area is exciting and bright with the introduction of new materials and new designs for implants. However, as with any new technology, there must be careful consideration of the safety of the devices, and their effectiveness will only be determined in long-term follow-up studies.
This report reviews data relating to the nickel hazard from implanted prostheses. It is shown that nickel is released from stainless steel prostheses by the action of sweat, blood and physiological saline solution. In laboratory animals, solubilized nickel isn the tissue near the implant.
Proplast and Plastipore prostheses, removed at revision surgery, have been examined under the electron microscope. Foreign material in the multinucleated foreign body giant cells, previously reported under the light microscope, has been confirmed. The appearances were consistent with the conclusion that the giant cells were breaking down the prostheses by two different modes of action. X-ray elemental analysis is of limited value in this investigation because of the low atomic number of the elements involved. However, such analysis of this foreign material was consistent with the conclusion that it arose from the prosthesis.
The anatomical basis and operative technique for insertion of mammary prostheses in the completely submuscular position are described. The results of 38 completely submuscular prostheses used for reconstructive breast surgery form the basis of this report. The two major advantages of the method, freedom from major complications, and a reduced incidence of deforming fibrous capsular contracture, have important implications in reconstructive breast surgery.
Eighty-nine patients were treated for impotence with penile prostheses. The Small-Carrion prosthesis was used in 56 patients, the inflatable prosthesis in 27 and Pearman's prosthesis in 6 patients. The overall functional results with the Small-Carrion and inflatable prostheses were comparable.
A modified surgical technique for application of extraluminal polypropylene spiral prostheses (PSP) to the trachea was developed. A portion of the segmental blood supply to the collapsed segment of trachea was maintained by fenestrating rather than completely dissecting the right lateral pedicle. Polypropylene spiral prostheses were applied to the cervical trachea of 12 dogs (group I) via the modified technique and to 12 dogs (group II) with the identical surgical dissection but without PSP applied. Clinical abnormalities included mild coughing in group I dogs and swelling of the incisions in both groups. Limited necrosis and moderate degeneration and inflammation were observed histologically in both groups. Pathologic changes were worse in the caudal cervical segment of the trachea. Mucosal regeneration was present on day 10 in both groups. Transmural tracheal necrosis was not observed. The modified technique for application of PSP is recommended by the authors because it provides adequate surgical exposure and the blood supply preserved by segmentally dissecting the right lateral pedicle is adequate to maintain tracheal viability.
Tracheoesophageal vocal prostheses (TVP) in laryngectomized patients commonly deteriorate due to overgrowth by yeasts, particularly Candida species. We describe the first case of colonization of such devices by a member of the Fusarium solani species complex in a patient with a history of glottal carcinoma. Three isolates, from three prostheses, were found morphologically consistent with the traditional picture of F. solani. Ribosomal sequence analysis showed that the isolates belonged to a distinct, as yet apparently unnamed phylogenetic species within the F. solani species complex. This species, one of two distinct genetic types (genotype 2) traditionally considered part of the plant-pathogenic subtaxon Fusarium solani f. sp. radicicola, has not previously been identified as an agent of human or animal disease, although it is closely related to a known etiologic agent of mycetoma, an Acremonium-like species recently renamed Fusarium falciforme. Sequence and multisatellite M13 polymorphism analysis revealed no distinctions among the case isolates. Production of cyclosporine was detected for all three case isolates.
A study of the walking activities of 243 individuals was carried out. The individuals came from four different occupations and had an age range of 17-83 years. The survey carried out in this investigation showed surprisingly little correlation between variables such as age, height, and weight of individuals and their speed of walking, length of stride, or distance walked. Correlation matrices were obtained for the whole sample and then for each sex, showing similar trends. The most significant correlation was between the height of an individual and the length of the stride, and there was a lesser correlation between age and the number of steps walked by an individual per day. Further statistical analyses showed that males in manual occupations walked most and those in sedentary occupations walked least. On the other hand, in the female groups housewives seemed to walk least and those in technical occupations walked most. The average number of steps walked per day by a male individual for the whole sample was 9537; that for females was 9839. The corresponding distances walked per day were 6.7 and 6.5 km. The differences were not statistically significant. Predictions of wear of prosthetic components made of ultrahigh molecular weight polyethylene were made on the basis of the above data and other variables affecting wear, such as the weight of the subject and the area available for contact during walking. Charts have been constructed of the penetration of the metallic component into the plastic one for both hip knee prostheses, thus enabling predictions of the wear of the plastic components of these two most widely used prostheses. Owing to the wide ranging values of the variables used in making the predictions of wear, these latter should be regarded only as 'safe' first estimates.
Under endoscopic and radiologic control, two types of self-expandable metal prostheses were implanted in tracheobronchial lesions to help reestablish airway caliber. Thirty-nine metal stent prostheses (6-20 mm in diameter) and 35 Gianturco stents (30 mm in diameter) were used in 55 adult patients with 62 lesions of the trachea (n = 33) or bronchi (n = 29). All lesions except one were endoscopically confirmed to be noninflammatory. Immediately after implantation, radiologic and endoscopic studies verified reestablishment of a satisfactory airway diameter in all patients. At a mean follow-up of 10.35 (range, 3-27) months, improvement in the respiratory status of 49 of the 55 patients (89%) was maintained and tolerance of the device was excellent. For the Wallstent endoprosthesis, the six complications observed at endoscopy were successfully treated. The Gianturco stent, however, led to a high rate of complications: 30% of cases had migration and/or rupture of the metallic mesh, potentially leading to obstruction or wall perforation; one case of respiratory distress was fatal. This procedure offers rapid epithelialization and incorporation of the device into the tracheobronchial wall.
The results of the evaluation of subjects presently fitted with internal auditory prostheses are summarized. Based on these results, the role of single-channel prostheses as a treatment for acquired deafness is discussed in terms of the auditory expectation for a single channel and of subject selection.
A prosthetic device might be indicated in craniofacial reconstruction when plastic surgery is impossible or when the final cosmetic result is unsatisfactory. However, the attachment of a prosthesis is often very difficult. Bone-anchored, skin-penetrating titanium implants have been used for retention of auricular prostheses in 38 patients. The patients have been followed up for 1 to 5 years. No patient has been lost to follow-up. Only 1 implant out of the 159 inserted was found to have failed to integrate. Two skin-penetrating abutments have been removed because of inflammation where they penetrated the skin. The surgical procedure as well as the manufacture of the prostheses and the attachment is presented in detail.
The technique of installing penile prostheses for treatment of erectile dysfunction in the male is becoming increasingly popular, particularly, but by no means exclusively in the cases of impotence in which biological factors are clearly implicated. The literature to date fails to take into account suprabiological factors such as the nature of the couple's sexual relationship and more particularly the sexual myths that shape their sexual behaviour. The author evaluated eight couples in which the male was seeking a penile prostheses and in all eight couples a variety of sexual myths had contributed to major sexual problems for the couple, even before the onset of the erectile dysfunction. A plea is made for discarding the false dichotomy or "organic" versus "functional", in favour of a list of etiological factors including the biological ones as well as suprabiological ones. Also, the installation of penile implants should only be considered after a full investigation of the couple's sexuality by a competent sex therapist and only when other forms of couple/sex therapy have failed.
The capture of highly accurate data describing the complex surfaces of the human body may prove extremely useful in many medical situations. The data provide a method of measuring and recording changes to the surface of a patient's soft tissue. The data may be applied to computer-controlled manufacturing techniques, such as rapid prototyping (RP). This enables accurate physical replicas of the patient topography to be produced. Such models may be used as an aid in the design and manufacture of prostheses. This paper describes an investigation aimed at identifying problems that may be encountered when scanning patients and describes the application of the resulting data in the design and manufacture of facial prostheses. The results of the experiment are presented together with a discussion of the accuracy and potential advantages afforded by this approach.
We report a child with bilateral congenital microtia in whom cosmetic and auditory rehabilitation has been effected using in-the-ear hearing aids within prostheses overlying the rudimentary external auditory meati after canaloplasty. This novel method of auditory rehabilitation has not been reported before and is suitable in selected cases. The prostheses themselves were successfully secured using a prosthetic contact adhesive we have developed that offers excellent retention, little if any skin reaction, and high patient acceptability.