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At least 235 records · Page 13Linked to original sources
PubMed2002

Preliminary ossiculoplasty results using the Kurz titanium prostheses.

OBJECTIVE: Limitations in biocompatibility and hearing improvement with ossicular chain reconstruction prostheses are addressed with new, lightweight titanium prostheses designed to maximize visualization of the capitulum and footplate regions. The effectiveness of these new prostheses is being tested in a prospective multicenter study. STUDY DESIGN: Prospective case series. SETTING: Multicenter (8 sites), primarily tertiary private practice or academic otologic clinics. PATIENTS: A convenience sample of 31 patients undergoing ossiculoplasty, with 16 partial ossicular chain reconstructions using the Bell prosthesis and 15 total reconstructions using the Aerial prosthesis. INTERVENTION: Ossiculoplasty using new Kurz titanium prostheses. Cartilage was interposed between the tympanic membrane and the prosthesis. MAIN OUTCOME MEASURES: Air-bone gap for pure tone average and 3,000 and 4,000 Hz, assessed preoperatively and 3 months, 6 months, and 12 months postoperatively; percent of patients obtaining an air-bone gap of </=20 dB; high-frequency average (1,000, 2,000, and 4,000 Hz) to evaluate sensorineural hearing loss; and extrusion rate. RESULTS: A postoperative air-bone gap of </=20 dB was obtained in 81% of Bell prosthesis patients and 67% of Aerial prosthesis patients at 3 months. The results were stable to improved for later time intervals. High-frequency gaps were similar to the pure tone average gap. To date, there have been no instances of extrusion, and all the surgeons found the prostheses easy to use and thought that the design characteristics facilitated accurate placement. CONCLUSIONS: Initial evaluation of the Kurz titanium prostheses produced low extrusion rates (none to date) with excellent hearing results, including good high-frequency conduction. Good visualization and accurate placement were easy to achieve. Further studies are needed to confirm long-term efficacy.

Audiometry, Pure-Tone↗
PubMed2004

Rotating platform components for revisions of hinged knee prostheses.

If hinged prostheses are revised with smaller and nonhinged prostheses, do these implants provide adequate fixation, do massive bone grafts in combination with smaller implants reinforce host bone stock, do less constrained prostheses restore ligament tension, and do they avoid problems of the extensor mechanism? To answer these questions, 20 failed hinges were revised to rotating platform revision prostheses with short intramedullary stems in a prospective study. Meticulous soft tissue release techniques and extensive bone grafts were used (tibia, impaction grafting in 16 cases, and structural grafts in four cases; femur, impaction grafting in four cases and structural grafts in 16 cases). The mean followup was 5.3 years (range, 2.3-10.5 years). The Knee Society score improved from a preoperative mean of 21 points (range, 7-49 points) to a mean 81.2 points (range, 59-94 points). One cementless tibial component with extensive impaction grafting became loose. The remaining components (95%) were well-fixed. All cancellous bone grafts showed trabecular remodeling. All structural grafts united to the host bone without resorption. All knees had ligamentous stability after surgery. There were no problems of the extensor mechanism. In this series the rotating platform revision prostheses were used successfully for failed hinged prostheses.

Adult↗
PubMed2004

Ankle arthroplasty using three generations of metal and ceramic prostheses.

Ankle arthroplasties using metal and polyethylene prostheses were done on 28 patients (30 ankles) with painful osteoarthritis or rheumatoid arthritis between 1975 and 1980. Significant loosening and subsidence of the metal prostheses occurred in most patients, and ceramic prostheses were introduced in 1980. Ceramic prostheses with or without cement were used to replace 60 ankles in 56 patients with painful arthritis between 1980 and 1991. Revision surgery was required for five patients (five ankles) during the followup period (mean, 12 years 6 months). Loosening and subsidence of the prostheses were seen in 50% of patients within 5 years after the index procedure. As a result, a new design of bead-formed alumina coated with hydroxyapatite was used. A tibial prosthesis fixed to the posterior cortex of the tibia with a screw was used from 1991. These new ceramic prostheses were used to replace 70 ankles in 62 patients between 1991 and 2000. Thirty-six patients (36 ankles) with a mean age of 71 years (range, 50-87 years) had osteoarthritis, and 26 patients (31 ankles) with a mean age of 60 years (range, 41-76 years) had rheumatoid arthritis. During followup, with an average of 5 years 2 months, three patients (three ankles) required revision surgery (one for infection, two for talar necrosis). Overall results for patients with osteoarthritis were excellent in 21 ankles, good in 10 ankles, fair in two, ankles and poor in zero ankles. Results in patients with rheumatoid arthritis were excellent in five ankles, good in 16 ankles, fair in three ankles, and poor in two. In the intermediate study, 29 patients (31 ankles; 91.2%) with osteoarthritis and 19 patients (21 ankles; 76.9%) with rheumatoid arthritis were satisfied with the short-time results of arthroplasty.

Adult↗
PubMed2004

Efficacy of antibiotic impregnation of inflatable penile prostheses in decreasing infection in original implants.

PURPOSE: We compared infection rates in original inflatable penile prostheses implants between prostheses impregnated with InhibiZone (American Medical Systems, Minnetonka, Minnesota), an antibiotic surface treatment, and prostheses without antibiotic treatment. MATERIALS AND METHODS: We retrospectively reviewed patient information forms filed with the manufacturer following original implantation in the United States to implant AMS 700 series penile prostheses (American Medical Systems) between May 1, 2001 and April 30, 2003. We compared results in 4205 men, including 2261 with a mean age of 60.71 years who received prostheses with InhibiZone, a surface treatment combining rifampin and minocycline hydrochloride, and a control group of 1944 with a mean age of 61.04 years who received untreated prostheses. Followup in the treatment and control groups was 0 to 11.5 months (mean 5 and 8, respectively). In the treatment group only implants in which all components were treated were included. RESULTS: The reported incidence of infection after 60 days was 0.28% in the treated group and 1.59% in the control group (p = 0.0034). After 180 days the infection rate in the treated and control groups was 0.68% and 1.61%, respectively (p = 0.0047). The treated group had an infection rate that was 82.4% lower than in the control group after 60 days and 57.8% lower after 180 days. Erectile dysfunction etiologies occurred at statistically similar rates in the 2 groups and did not impact infection rate results. CONCLUSIONS: The use of InhibiZone to target postoperative infections results in a statistically significant decrease in penile prosthesis infection rates in original implants. Infection rates in the control group were consistent with those in the published literature.

Anti-Bacterial Agents↗
PubMed2006

Hardness evaluation of penile prostheses.

AIM: This work investigates the hardness and buckling force of penile prostheses to further understand the rigidity of penile prostheses before and after implantation. METHODS: Evaluated herein are four prosthetic samples (three inflatable, one semi-rigid), five real prostheses (one inflatable, four semi-rigid), and one prosthesis after implantation. The hardness is measured with a Shore Durimeter by pressing the tester's indentor to the surface of the specimen. A volunteer with inflatable prosthesis implantation is evaluated with respect to penile hardness versus various numbers of pumping. The buckling force of the prosthesis is also determined by a push-pull gauge and a specially designed sampling table. RESULTS: Results in this study demonstrate that although the inflatable prosthesis could only be pumped to a certain amount of hardness, hardness and buckling force correlate well with each other. After reaching the hardness limit, prostheses can even be pumped a further few times. However, continuous pumping only puts more tension on the prosthetic material without increasing hardness and could induce mechanical failure of the prosthesis. Results also indicate that the buckling force decreases with increasing length of the semirigid prostheses, and increases when the prosthesis has a larger diameter. CONCLUSION: This mechanical measurement of rigidity in penile prostheses could provide more information to clinicians about the penile prosthesis before surgical implantation, and to patients about prosthesis usage after implantation.

Hardness Tests↗
PubMed2006

An audit of implanted penile prostheses in the UK.

OBJECTIVE: To assess whether the outcome of implanting penile prostheses is related to the number of prostheses implanted by surgeons, as several reports showed that the outcome of a urological procedure is directly related to the experience of the surgeon. METHODS: We conducted a retrospective audit of 413 penile prostheses implanted over a 2-year period in the UK by 76 surgeons. RESULTS: About 80% of the surgeons implanted only one or two prostheses per year, usually of the malleable type, and usually on patients in the private sector. Only four surgeons implanted >20 prostheses per year. The overall revision rate for implantation in the UK, at 24%, is far higher than the worldwide average. CONCLUSIONS: Guidelines are needed on the number of prostheses a surgeon should implant per year so that revision rates will decline to more acceptable levels and patients will be offered a genuine choice of product.

Erectile Dysfunction↗
PubMed1998

Measuring patient satisfaction with mandibular prostheses.

OBJECTIVES: Previous research has shown that patients' evaluations of their prostheses correlate poorly with the clinicians' assessments, as well as with intraoral anatomic factors. It has been recommended that researchers conduct more studies that use patient satisfaction as the primary outcome measure in treatment evaluation and that more attention be paid to understanding exactly what measures of patient satisfaction represent. In this study, the relationship between patients' ratings of general satisfaction and their perceptions of different aspects of mandibular prostheses is investigated. METHODS: One hundred and twenty subjects applied to participate in a randomized controlled clinical trial comparing two types of mandibular prostheses: conventional dentures and implant prostheses. At baseline, they were asked to rate on 100 mm visual analog scales (VAS) factors that edentulous patients indicated were important to them. These included comfort, ability to chew, stability, esthetics, ability to speak and ease of cleaning of their conventional dentures. Subjects were also asked to rate their general satisfaction with their dentures. In addition, they selected the one quality of their denture that they considered to be most important. RESULTS: Multiple regression methods revealed that gender, as well as patients' ratings of comfort, stability, esthetics, ability to chew and ability to speak with their prostheses contributed significantly to general satisfaction (F<0.0001). Furthermore, 89% of the variation in ratings of general satisfaction was explained by these factors. In addition, patients who considered ability to chew as the most important factor associated with their dentures rated their general satisfaction significantly higher than the other subjects (P=0.0003). CONCLUSION: Patient satisfaction with conventional dental prostheses is highly dependent on gender, and the appearance and functionality of the appliance. The combined effect of these factors explained most of the variation in the satisfaction ratings.

Adult↗
PubMed1986

Auscultatory characteristics of normally functioning Lillehei-Kaster, Björk-Shiley, and St Jude heart valve prostheses.

Auscultatory and echocardiographic and phonocardiographic studies were performed on 26 patients who had a total of 11 Lillehei-Kaster, 16 Björk-Shiley, and 18 St Jude heart valve prostheses functioning normally in the aortic or mitral positions or both. With all types and positions of prostheses a distinct closing sound was always detected. It was frequently heard in two parts which, according to echocardiographic and phonocardiographic studies, resulted from the onset and completion of the valve closure. An opening sound could be heard from all Björk-Shiley and St Jude valves but from only four of the 11 Lillehei-Kaster valves. The opening sounds due to mitral prostheses consisted of two to three closely spaced clicks detected as a faint early diastolic crackle on auscultation. Echocardiography with phonocardiography indicated that they were related to the onset and termination of the disc opening excursion. In the aortic position the valves always produced early to mid-systolic murmurs, and a soft early diastolic murmur was also heard in seven of 23 patients. A mid-diastolic rumble was heard in 12 of 22 patients with mitral prostheses. Normally functioning tilting disc valve prostheses produce characteristic auscultatory findings, and familiarity with these findings will be useful in clinical evaluation of patients with these prostheses.

Adult↗
PubMed1993

Doppler hemodynamic profiles of 82 clinically and echocardiographically normal tricuspid valve prostheses.

BACKGROUND: Normal Doppler hemodynamics for tricuspid prostheses have not been well characterized in a large group of patients. Therefore, we analyzed comprehensive Doppler echocardiographic examinations of 82 patients with tricuspid prostheses that were normal by clinical and two-dimensional echocardiographic examinations to establish the normal hemodynamics of various types and sizes of tricuspid prostheses. METHODS AND RESULTS: The earliest complete postoperative echocardiographic study from each patient was chosen for analysis. Doppler examinations were analyzed on an off-line station from tapes or Doppler strip charts. Early velocity, atrial velocity, end-diastolic velocity, pressure half-time, and mean gradient were obtained by digitizing tricuspid velocity curves. The incidence of "physiological" tricuspid prosthetic regurgitation was noted. Ten Doppler cycles were measured for each patient, and maximal, minimal, and average measurements were recorded. The mean values +/- SD of early velocity, atrial velocity, end-diastolic velocity, mean gradient, and pressure half-time and incidence of mild prosthetic regurgitation were reported for each type of prosthesis, as were highest Doppler measurements for each valve type. Average pressure half-time was significantly lower for St Jude than for heterograft prostheses (P = .04). There were no significant differences between the valve types for mean gradient, early velocity, or incidence of prosthetic regurgitation. Increasing prosthesis size was associated with lower average pressure half-time for heterograft prostheses (P = .024). Average differences (respiratory- and cycle-length-dependent) between maximal and minimal values for 10 cardiac cycles were established for each prosthesis. CONCLUSIONS: This study establishes normal ranges for Doppler hemodynamics of various tricuspid prostheses and emphasizes the importance of measuring multiple cycles for each tricuspid prosthesis, regardless of cardiac rhythm.

Adolescent↗
PubMed1992

Engineering design of vascular prostheses.

The replacement and bypass of arteries of diameter greater than 6 mm with textile vascular prostheses has proved very successful since they were first introduced forty years ago. Although manufacturers continue to improve their products and make them of consistent quality for increased safety and performance and to facilitate their use by surgeons, most of the research work in this area is concerned with the development of small-diameter prostheses. Current expanded PTFE and textile prostheses do not perform satisfactorily when their diameters are reduced to less than 6 mm. For the small-diameter prostheses it will be necessary to develop less thrombogenic materials and to design the structure of the prostheses more closely to match the mechanical properties of the natural arteries. The purpose of this paper is to discuss the design requirements and to review the development of large- and small-diameter vascular prostheses.

Biocompatible Materials↗
PubMed1993

Lightweight prostheses for bilateral below-elbow amputees.

In view of the anticipated activity of the patient and working environment, lightweight prostheses were designed for an adult female, bilateral below-elbow (BE) amputee at NIRTAR to provide the greatest degree of function. The prostheses were fabricated using lightweight materials and new techniques. Depending on the stump length there were two different types of lightweight prostheses designed and successfully used, (1) an endoskeletal BE prosthesis and (2) an exoskeletal BE prosthesis. After periodic follow-up and evaluation the function of the prostheses was found to be most satisfactory. By reducing the weight considerably compared to other available alternatives, it is more likely that the amputee will make use of the prostheses to efficiently perform various activities. The new prosthesis designs may counteract the high rejection rate of old conventional ones and the principle may be applied to the fabrication of all BE prostheses.

Activities of Daily Living↗
PubMed1999

Evaluation of use and durability of polypropylene trans-tibial prostheses.

Forty-three (43) trans-tibial prostheses with a mean period of use of 33 months were evaluated in terms of utilisation and durability. The majority of the prostheses (80%) were worn by amputees with demanding occupations, such as farmers, fishermen and tradesmen. The prostheses were in use approximately 9 hours per day. No major or frequent breakdowns of the polypropylene prosthetic components were found. The suspension belts were the parts most frequently affected; a total of 32 needed replacement after an average 11 months of use. Eleven (11) prostheses were completely replaced, more than half at least partly because of socket-fitting problems. In all, socket-fitting problems were found in 15 prostheses, causing pain and consequently limitation of use. While the prosthetic polypropylene components were satisfactory, the rubber foot was a major cause of early breakdown. A total of 40 feet were replaced; their mean period of use before breakdown was 9 months. In practice, parts were frequently replaced at a later stage than desirable, meaning that there was frequent "overuse" of prostheses with worn parts. Measures were taken to increase the life span of the prosthesis: change in the design of the foot; issuing a spare foot with the prosthesis; strengthening the suspension belt. Additional evaluations are necessary to confirm the degree to which the findings are representative.

Adolescent↗
PubMed1998

Cost of prostheses in patients with unilateral transtibial amputation for vascular disease. A population-based follow-up during 8 years of 112 patients.

We analyzed the cost of prostheses for patients amputated because of vascular disease. During 1 year, 112 patients were treated with a primary unilateral transtibial amputation in Malmöhus county, Sweden, which has 527,000 inhabitants. During the first 6 months after the amputation, 50% (56/112) of the patients had received a prosthesis. At 6 months, 49 patients (7 had died) were examined, 18 had poor and 31 had good prosthetic function. Within 1 year, 71 (63%) patients had been fitted with a prosthesis. During 8 years after the amputation, they received altogether 137 prostheses and 54 exchange sockets; 59% of the prostheses and 26% of the sockets were delivered during the first year. Each patient received a median of 1 prosthesis and 1 extra socket. During the 8-year period, the total cost of prostheses, sockets and maintenance for the 71 patients was USD 228,746, representing a median cost of USD 1,582 per patient. The total cost of maintenance of the prostheses during the same period was USD 37,959, representing 20% of the total cost of all the prostheses and sockets. There was no statistically significant difference in the costs between patients with good or poor function.

Adult↗
PubMed1999

Proximally porous-coated ingrowth prostheses: limits of use.

Callaghan has suggested that the most important factor in obtaining optimal results after total hip arthroplasty may be the ability to determine when to use cemented or cementless fixation. This article has presented the indications and relative contraindications for use of proximally porous-coated prostheses. Midterm results suggest that with appropriate patient selection, excellent clinical results can be achieved with currently available proximally porous-coated prostheses. Use of proximally coated prostheses is indicated for primary total hip arthroplasty in patients aged >70 years with good bone stock. Relative contraindications are based on interference with bone ingrowth or with the ability to achieve a congruent fit, both of which preclude establishment of rigid initial stability. These conditions include metabolic bone disease such as osteoporosis, osteomalacia, Gaucher's disease, sickle cell disorders, and Paget's disease; significant anatomical distortion, as seen in developmental dysplasia of the hip with anteversion, prior osteotomy, or intertrochanteric fracture; Dorr type C bone; and current treatment with radiation, chemotherapy, indomethacin, or diphosphonates. The same relative contraindications to use are applicable in revision situations. Further, proximally porous-coated prostheses should not be used for revision arthroplasty in the setting of massive bone loss, limited life expectancy, or inability to participate in protected weight bearing. These devices may be used successfully in revision arthroplasty when the hip has minimal or moderate bone loss, and occasionally in the setting of severe bone loss. As further information is revealed through the long-term (10-20 years) results of proximally coated prostheses, further refinements and knowledge of the indications and contraindications for the use of these prostheses will be revealed.

Arthroplasty, Replacement, Hip↗
PubMed1999

In vitro stress analyses of dental implants supporting screw-retained and cement-retained prostheses.

A photoelastic and strain gauge analysis was performed to evaluate the stress transferred to implants through the provisional-cement-retained, the permanent-cement-retained, and the screw-retained prostheses. The deflections of the prostheses at the time of the loading were also measured. In the single crown test, the provisional-cement-retained crowns transferred less stress. In the two-unit fixed partial denture test, there were no differences between the three different prostheses. In the two-implant supported distal cantilevered prostheses, the screw-type and the permanent-cement-retained prostheses developed more stress around the apex of both implants. The permanent-cement-retained prostheses acted almost the same as the screw-type.

Birefringence↗
PubMed1999

Utilization of prostheses among US veterans with traumatic amputation: a pilot survey.

No random surveys have been done to determine how effectively veterans with amputation can utilize their prostheses, and only one limited survey has been done of Scandinavians' use of lower-limb prostheses. A pilot survey of prosthetic problems was sent to all 170 US veteran soldiers who had traumatic amputations over the last 10 years, whose addresses could be supplied by the VA, and whose medical synopses showed them to be otherwise healthy when leaving the military. This subpopulation was selected as a "best case" group: those most likely to be active, young, and healthy enough to use their prostheses, as well as close enough to the military and veterans medical systems to get adequate treatment. If they have problems, the rest of the veterans with amputation, relatively older and more debilitated, are very likely to have far worse problems. Although only 45 responded (26%), all had significant problems using their prostheses for work. Most problems were related to the attachment method. Even if all nonrespondents were problem free, at least a quarter had very significant problems using their prostheses. This means that there are significant problems with current methods for attaching prostheses that need to be addressed. The first step should be a large survey of veterans with amputation to get an accurate assessment of the extent of prosthesis-related problems.

Amputation Stumps↗
PubMed2002

[Major reconstructions of the hip by allograft composite prostheses (long-term follow-up of 34 cases)].

Reconstruction after major resections of malignant tumors can be achieved by association of prostheses and of massive allografts. In 34 patients, we could reconstruct: the proximal femur in 21 cases, after an average resection of 180 mm, with a "composite" allograft prosthesis (with a bone graft around the stem) or a "composite and combined" allograft prosthesis (in which the femur allograft was associated with the trochanteric tendons, to facilitate the reinsertion of the glutei muscles); 10 hemipelvis in which the cup was inserted in an hemipelvic allograft; 3 proximal femurs and acetabulum (with composite cups and stems). In comparison with metallic reconstruction prostheses, composite prostheses improved function, limited complications, and increased longevity. The association of allografts and prostheses not only allows reconstructions which could be hardly achieved with only prostheses (especially for the pelvis), but also improves functional result and longevity, thanks to the biological fixation of the osseous and tendinous allografts. Considering our 15 years follow up in oncology, we have now extended these procedures to the major bone losses of the femur and pelvis following iterative revisions of standard prostheses for arthritis.

Acetabulum↗
PubMedDate not supplied

Interaction between vascular prostheses and rifampicin in the prevention of the grafts infection. An experimental study.

Infections caused by synthetic prostheses are relatively rare (1.5-6%) but serious complication in vascular surgery. There is no doubt that during and immediately after surgery bacterial contamination may occur. An in vitro study was carried out in the Vascutek laboratories, which revealed a high affinity between prostheses in Dacron gel and Rifampicin. This affinity, the result of an ionic bond, was demonstrated by the fact that after 5 days Rifampicin was still present on the prostheses. Encouraged by this result, an experimental study was carried out in sheep. Five sheep were operated on making a prosthetic graft in both of the common carotid arteries: on one side a Gelseal Dacron prosthesis was implanted after being soaked for 15 minutes in a solution containing 1 mg/ml Rifampicin. A Knitted Dacron prosthesis was implanted in the contralateral carotid artery, again after pretreatment with Rifampicin. Explants were made after 2, 24, 48, 72 and 96 hours, and the concentration of Rifampicin on the prostheses was assessed on the basis of the diameter of the inhibition area on Staphylococcus aureus cultures. The results showed that the Gelseal Dacron prostheses maintained Rifampicin concentrations with an antibacterial activity up to 72 hours; this property disappears with the Knitted Dacron prostheses after only 24 hours. These results confirm the high affinity of Gelseal Dacron and Rifampicin also in in vivo experimental models.

Animals↗