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PubMed1977

[Assorted aluminium-oxide ceramic heads for prostheses of the hip-joint. A preliminary communication (author's transl)].

In the search for even more hard-wearing prostheses of the hip, a rotating total- and femoral head prosthesis and a total- and femoral head prosthesis with fixed detachable heads are described, the head of which is made from highly polished aluminium oxide ceramic, Biolox. For total prostheses the excellent gliding features between ceramic head and polyethylen acetabulum are being used. They will also permit return to proved metal-polyethylen prostheses, should the ceramic head fracture. The fracture prosthesis provides both such an exchange and conversion into a total prosthesis. Extending the present programme of rotation-prostheses to ceramic heads will require a wide assortment of heads. This will mean not only wide adaptability but also the need for detailed knowledge of this assortment, the use of which demand thorough preparation of the surgeon. In order to collect material of the use of these prostheses, the authors are very keen to hear of drawbacks- and without reticence-as soon as possible. Publication of our own experience will follow this preliminary communication in due course.

Aluminum↗
PubMed1997

Use of dobutamine stress echocardiography in assessing mechanical aortic prostheses: comparison with exercise echocardiography.

BACKGROUND AND AIMS OF THE STUDY: Relatively high resting flow velocities are occasionally seen in asymptomatic patients with apparently normal mechanical aortic prostheses. Doppler echocardiography in conjunction with bicycle exercise or dobutamine have been used to 'unmask' symptoms or abnormal hemodynamics in these patients. The aim of this study was to compare the Doppler-derived hemodynamic response to exercise and to dobutamine in patients with normally functioning mechanical aortic prostheses. METHODS: Bicycle ergometry (from 200-400 kg x m/min) and dobutamine (from 5-40 micrograms/kg/min) in conjunction with Doppler echocardiography were performed in 25 asymptomatic patients (21 men, four women; mean age 61 years) with mechanical aortic prostheses (range: 19 mm to 27 mm) who had normal resting hemodynamics and normal left ventricular function. Aortic valve area (continuity equation) and maximal instantaneous and mean gradients were estimated at rest and at peak stress. RESULTS: Target heart rate was achieved in 10/25 (40%) patients with exercise, and in 21/25 (84%) with dobutamine (p < 0.005). At peak stress, exercise induced a 25% increase in peak flow velocity, a 55% increase in valve gradients, and no significant change in valve area. In comparison, dobutamine induced a 48% increase in peak flow velocity, a 105% increase in valve gradients, and also no significant change in valve area. The flow velocity and pressure gradients at peak stress were significantly higher with dobutamine than with exercise. CONCLUSIONS: In normally functioning aortic valve prostheses, the target heart rate can be reached more often with dobutamine than with supine bicycle exercise. Despite significant increase in the transvalvular gradients, the valve area remained unchanged. The clinical significance of exercise or dobutamine in symptomatic patients with mechanical prostheses is yet to be proven.

Adult↗
PubMed1977

[The biological prostheses of Hancock in our experience of 250 subjects underwent a valvular replacement (author's transl)].

In this study we present the results of 5-years Follow-up of Clinical experimentation with biological prostheses of Hancock in 250 patients underwent a valvular replacement at the Cardiovascular Surgery Institute of Padua University in Verona. We report the immediate and long-term results with the death causes and the complications related above all with thrombo-embolic events. For such complications it was done a comparison relatively to the cases with mitral and aortic prostheses, with the results obtained from another Cardiovascular Surgery Center where are always applied artificial prostheses. From this comparison results that Hancock's biological prostheses has a major tendency to give incidence of embolic in the first months following the valvular replacement, but successively it is clearly to be prefered to artificial prostheses.

Evaluation Studies as Topic↗
PubMed1998

Penile prostheses in the management of impotence in patients with end-stage renal disease.

Erectile dysfunction, which has multifactorial causes including uremia, diabetes mellitus, hypertension, vascular insufficiency, autonomic neuropathy, and psychogenic pathology, occurs in a majority of patients with end-stage renal disease. After evaluation in the Sexual Dysfunction Clinic to exclude reversible disorders that may cause erectile dysfunction, hormonal supplementation, vacuum erection devices, and a self-injection program are offered to patients. Due to concern about patient's immunocompromised status, penile prostheses have not been considered appropriate therapy for those on dialysis or for renal transplant recipients. We report our 8-year experience with penile prostheses in 12 ESRD/renal transplant patients. Eleven patients have maintained their prostheses. Three patients had prostheses with mechanical failures that required reimplantation, and one prosthesis became infected and was explanted. Penile prostheses can be successfully implanted without excessive risk of infection in patients with erectile dysfunction resulting from end-stage renal disease.

Erectile Dysfunction↗
PubMed1998

Gold prostheses for ossiculoplasty.

OBJECTIVE: To review the results of ossicular chain reconstruction with partial and total ossicular replacement prostheses made of gold. STUDY DESIGN: Retrospective case review. SETTING: A tertiary referral center. PATIENTS: Fifty-nine patients underwent surgery between November 1993 and February 1996 and underwent follow-up for at least 12 months. Tympanoplasty was performed because of cholesteatoma, chronic otitis media, adhesive otitis media, and trauma. INTERVENTION: Tympanoplasty and ossiculoplasty with partial or total replacement gold prostheses. MAIN OUTCOME MEASURE: The clinical and hearing results of ossiculoplasty. RESULTS: In 62% of the patients in whom partial ossicular replacement prostheses were used, the residual air-bone gap could be reduced to < or =20 dB. In cases with total ossicular replacement prostheses, the air-bone gap could be closed to < or =20 dB in 42%. Extrusion of the prosthesis occurred in 11 cases (19%) between 7 and 21 months after tympanoplasty. In most extrusion cases (55%), this was combined with a significant retraction of the tympanic membrane. Primary and staged procedures showed different extrusion rates. CONCLUSIONS: Hearing results in the current study are comparable to results described by other authors for synthetic middle ear prostheses. Implant rejection was never encountered, with the gold implants exhibiting a high biocompatibility. Nevertheless, prosthesis extrusion occurred rather often in the course of tympanic membrane retraction. Staging the surgery or different shaping of the prosthesis may be helpful to prevent prosthesis extrusion.

Adolescent↗
PubMed2005

Composite prostheses used to repair abdominal wall defects: physical or chemical adhesion barriers?

In a composite prosthesis, the component placed at the peritoneal interface takes the form of a physical or chemical barrier. In this experimental study performed on the white New Zealand rabbit, several composites were examined to establish the effectiveness of these barriers at impeding adhesion formation. The biomaterials tested were two polypropylene prostheses (PP) with the physical barriers of expanded polytetrafluoroethylene or polyurethane (PP + ePTFE and PP + PU) and two prostheses (one polyester and the other PP) with the absorbable chemical barriers of polyethylene glycol/glycerol and hyaluronate, respectively (PO + gl and PP + hy). The composites were used to repair 7 x 5 cm defects created in the abdominal wall of the animals by placing the implant in contact with the visceral peritoneum and the subcutaneous tissue and fixing it to recipient tissue by 4/0 polypropylene running suture. Fourteen days after surgery the animals were sacrificed and specimens were taken for light microscopy and scanning electron microscopy. Adhesions developing at the prosthesis/visceral peritoneal interface were quantified. All the prostheses induced optimal mesothelialization. Composites with physical barriers behaved similarly in terms of provoking adhesions. However, the prostheses with chemical barriers differed in their effectiveness at preventing adhesions. Overall, the best results were obtained with the PP + PU composite.

Abdominal Wall↗
PubMed1992

In vivo fragmentation of microporous polyurethane- and copolyesterether elastomer-based vascular prostheses.

A previous study showed that microporous, compliant and (bio)degradable vascular prostheses prepared from a polyurethane/poly(L-lactic acid) mixture can function as a temporary scaffold for the regeneration of small-calibre arteries. In this study the mechanism of fragmentation of vascular prostheses made of polyurethane, copolyesterether and blends of either polyurethane or copolyesterether with polymers differing in biodegradability, crystallinity and glass transition temperature is investigated. Animal studies revealed that after 6 wk of implantation only the prostheses made of blends containing a second polymer which was non-elastic at 37 degrees C were fragmented extensively, whether the second polymer was (bio)degradable or not. It is concluded that fragmentation of the prostheses is mainly caused by alternating stresses induced by the arterial pulsations and that (bio)degradation plays a minor role.

Animals↗
PubMed1995

Removing fresh tissue from explanted polyurethane prostheses: which approach facilitates physico-chemical analysis?

Chemical, physical and structural analyses of polymers from explanted vascular prostheses are frequently jeopardized because of incomplete removal of the encroaching host tissue. In this study, microporous polyurethane arterial prostheses implanted as a canine thoraco-abdominal bypass were explanted after 1 and 12 months and were cleaned without fixation using four different digesting enzyme treatments, including collagenase, pancreatin and trypsin alone and collagenase and pancreatin in series, followed by washing in a solution of Triton X-100 detergent. By following this approach all the fresh tissue attached to the external and internal walls of the prostheses was removed with minimal damage to the underlying synthetic polymer. The morphology of the explanted and cleaned polyurethane prostheses could be obtained readily by light and scanning electron microscopy. Surface microporous features and the presence of polyurethane microfibres that had experienced in vivo biodegradation could therefore be identified easily. The surface and bulk physico-chemical properties of the polyurethane polymer were determined by electron spectroscopy for chemical analysis, attenuated total reflectance-Fourier transform infrared spectroscopy and differential scanning calorimetry. It was found that the most successful approach for removing fresh tissue and exposing a clean and uncontaminated polyurethane surface was to incubate the explanted samples first in collagenase followed by digestion in pancreatin. This particular cleaning technique has proved valuable in enabling us to monitor small in vivo changes in the surface chemistry and in the bulk microphase segmented structure of polyurethane biomaterials.

Animals↗
PubMed1993

Changes in photon dose distributions due to breast prostheses.

PURPOSE: Subcutaneous prosthetic implants had been routinely used for cosmetic augmentation and for tissue replacement following mastectomy over the last 15 years. The implants come in many forms as the gel filler material and surrounding shell material(s) vary significantly. METHODS AND MATERIALS: This study uses a thin window parallel-plate chamber and thermoluminescent dosimeters to quantify and dosimetric changes to surrounding breast tissue due to the presence of the prosthesis. A mammographic phantom was compared to four commercial prostheses, namely two silicon gel fillers within two different shells (silicon or silicon/polyurethane), a tri-glyceride within silicon and a bio-oncotic gel within silicon/polyurethane. The latter two implants were designed with a low-Z fill for diagnostic imaging benefits. RESULTS: Ion chamber results indicate no significant alteration of depth doses away from the implant with only minor canceling (parallel opposed) interface perturbations for all implants. In addition the physical changes to the irradiated prostheses were quantified by tonometry testing and qualified by color change. Each implant exhibited color change following 50 Gy, and the bio-oncotic gel became significantly less formable following irradiation, and even less formable 6 weeks postirradiation. CONCLUSION: The data indicates that prostheses do not affect the photon beam distribution, but radiation does affect the prostheses.

Breast↗
PubMed1995

Hygiene procedures for implant-retained facial prostheses.

Implant-retained facial prostheses offer several advantages over facial prostheses that are retained with conventional skin adhesive. However, implant-retained prostheses also require additional hygiene procedures to maintain them in good condition and to keep the implants and retentive elements free of debris and the surrounding skin healthy. This article describes additional hygiene procedures to maintain the implant-retained prostheses.

Adhesives↗
PubMed1996

Craniofacial osseointegration: technique for bar and acrylic resin substructure construction for auricular prostheses.

Retention of auricular prostheses with adhesives is frequently problematic. Craniofacial osseointegrated implants have become an accepted biotechnique used in auricular reconstruction. This article describes a procedure for bar and acrylic resin substructure construction that allows for the incorporation of desired features. The most common means of retaining auricular prostheses is with bar and clip systems. For auricular prostheses, two implants are placed with the bar designed to minimize torquing on the implants and to facilitate hygiene. Additionally, the bar should not have to be removed from the patient when new prostheses are to be constructed. The procedure provides for a more biomechanically effective bar construction and efficient means of constructing replicate acrylic resin substructures.

Acrylic Resins↗
PubMed1982

Rate of diffusion of Solu-Medrol across the silastic membranes of breast prostheses-an in vitro study.

Many plastic surgeons have used steroids in breast prostheses in augmentation and postmastectomy reconstruction to prevent capsular contracture. The detection and incidence of complications have increased during the last several years. It is probable that the incidence of complications is related to two factors. First, clinicians have used the same doses in the smaller outer compartments of bilumen implants, giving a much higher concentration of steroid. Second, the more recent implants have thinner envelopes. Tritiated Solu-Medrol was placed in the outer lumen of the bilumen Heyer-Schulte, McGhan, and Surgitek prostheses, and in the only lumen of inflatable Mammatech and Heyer-Schulte prostheses. Diffusion of the Solu-Medrol from each of these identically sized prostheses into the surrounding saline bath was measured with a liquid scintillation counter. Diffusion rates provided concentration-dependent, as predicted by Donnan-Gibbs equilibrium. The silicon gel in bilumen implants was found to represent a second Donnan-Gibbs equilibrium and result in a lower diffusion rate because of affinity for the steroid.

Breast↗
PubMed1985

Computed tomographic evaluation of non-metallic middle-ear prostheses.

Non-metallic middle-ear prostheses, including a plastipore total ossicular replacement prosthesis (TORP) and partial ossicular replacement prosthesis (PORP), a Teflon loop stapes piston, and a Ceravital PORP were used to reconstruct the ossicular chain in formalin fixed cadaver temporal bones. The temporal bones were examined using high resolution, thin-section computed tomographic techniques identical to those used for patient studies. The detail and resolution of the images were comparable with those obtained on standard patient exams. The temporal bones were evaluated to determine the appearance of the prostheses in normal and abnormal positions within the middle ear. The radiologist examined the images without fore-knowledge of the position of the prostheses and was able to accurately identify both normal and abnormal positions. With the proper technique an accurate evaluation of non-metallic middle-ear prostheses is possible by high-resolution computed tomography.

Cadaver↗
PubMed1979

Effects of diffused soluble steroid on capsules around experimental breast prostheses in rats.

Saline-filled miniprostheses were implanted beneath the dorsal panniculus carnosus of rats. The control prostheses contained only saline, while the experimental prostheses contained soluble methylprednisolone sodium succinate. At 10-day intervals the in situ compressibility of the tissue mound around the implants was measured mechanically. At 60 and 120 days, the control mounds were harder than those around the steroid prostheses, and the control prostheses were surrounded by a thicker capsular membrane. The control capsules contained more non-collagenous protein than the steroid modified capsules. We suggest that this non-collagenous protein may be related to the proteopolysaccharide cement which binds the fibers of immature scar together--and that the effect of our steroid treatment was to reduce this proteopolysaccharide component of the capsule membrane and thereby cause its dissolution.

Amino Acids↗
PubMed1982

Late side effects related to inflatable breast prostheses containing soluble steroids.

Long-term follow-up of 12 patients who have undergone augmentation mammaplasty with breast prostheses containing 62.5 mg of methylprednisolone hemisuccinate is presented. Significant complications, including prosthesis ptosis, atrophy and thinning of overlying breast tissue, impending extrusion, and capsular contracture are discussed. Excellent results can be followed by significant complications many years later. Many of these changes are reversible when steroid-containing prostheses are exchanged for new nonsteroid prostheses. Long-term follow-up of patients who have undergone augmentation mammaplasty with prostheses containing steroids is recommended.

Atrophy↗
PubMed1990

Long-term use of polyurethane breast prostheses: a 14-year experience.

I have used polyurethane prostheses for the past 14 years, implanting 220 implants into 130 patients who desired breast reconstruction after subcutaneous mastectomy or cancer ablation or simply breast augmentation. I theorize that a polyurethane-covered implant resists contracture, retaining its compressibility because the fibroblasts proliferate into the polyurethane in many different directions. When the fibrils contract, the forces of contracture counterbalance one another, resisting contracture. However, when smooth prostheses are implanted, fibrils are directed in a circular fashion around the implant and naturally contract, leading to firmer breasts. There were 115 prostheses inserted following subcutaneous mastectomy, and 22 percent developed contracted capsules. Seven implants became exposed because of skin necroses; one was removed because of a Staphylococcus infection; and two patients developed a combination of polyurethane and silicone granulomas. These developed only with the earlier implant, where there was shedding of the polyurethane sponge layer and silicone bled from the low-viscosity silicone used in the earlier implants. No granulomas were noted with the currently used Surgitek Replicon implant. Eighty-five breasts were reconstructed after cancer ablation with polyurethane implants, and the contracture rate was 2.3 percent. Other complications were minimal. A smaller group of patients had augmentation mammaplasty, and 20 prostheses were placed in 10 patients. A 15 percent contracture rate was noted in this group. In this study, 82 percent of patients were followed for up to 14 years. Capsular contractures occurred in 30 implants between 1 and 11 years, for an average recurrence at 6.3 years. The overall contracture rate was 13 percent. Other complications were minimal. All implants were placed subcutaneously or subglandularly, and all were drained.

Breast↗
PubMed1994

Silicone breast prostheses and rheumatic symptoms: a retrospective follow up study.

OBJECTIVES: To determine whether women with silicone breast prostheses have more rheumatic complaints than controls. METHODS: The study included 287 women who had silicone breast prostheses implanted between 1978-90. For every patient a female control of the same age was selected who had had an aesthetic operation in the same year. A questionnaire was sent to this retrospective cohort of women with silicone breast prostheses and controls. RESULTS: Questionnaires were returned by 235 cases (82%) and 210 controls (73%). Patients reported more symptoms arising after surgery than controls (0.6 v 0.3 complaints per subject, p < 0.001). The average interval between surgery and onset of complaints was 5.1 years for patients and 5.9 for controls. Complaints presented by patients were: painful joints (p < 0.005), burning eyes (p < 0.01), and skin abnormalities (p < 0.005). Differences in the use of antirheumatic drugs or medical consultations related to rheumatic symptoms did not reach statistical significance. Further information obtained from the patients and controls reporting rheumatic symptoms did not reveal the presence of a specific syndrome in connection with silicone materials. CONCLUSION: Women with silicone breast prostheses report more rheumatic complaints after silicone implantation than controls, but there is no evidence of increased prevalence of common rheumatic diseases.

Adult↗
PubMedDate not supplied

Quality of life among mastectomy patients using external breast prostheses.

BACKGROUND: Most women who undergo mastectomy for breast cancer use external breast prostheses. Yet, little is known about patterns of use, satisfaction levels, and quality of life associated with their use as compared to other options. PATIENTS AND METHODS: We report longitudinal, self-report questionnaire data regarding prosthetic use from 592 Italian mastectomy patients. Women who report satisfaction with their prostheses are compared on medical, demographic, and quality of life variables to a matched sample of women who report dissatisfaction. We also compare matched samples of women who do not use prostheses and women who had reconstruction to prosthetic users. RESULTS: Most women used and were satisfied with their prostheses. However, there was a small group of women who were dissatisfied. These women reported greater disruption to their sense of feminility and worse quality of life in some areas. We found few differences between prosthetic users and women who used either of the other two options available following mastectomy-taking no action to restore the appearance of the amputated breast or having reconstructive surgery. CONCLUSIONS: No one technique for restoring the appearance of the mastectomized breast is necessary to optimize quality of life for all women. Physicians should describe the options to women, along with the average satisfaction rates for women choosing those options, and help women to make the best personal decisions.

Body Image↗