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At least 613 records · Page 34Linked to original sources
PubMed1996

Albumin-impregnated polyester vascular prosthesis for abdominal aortic surgery: an improvement?

AIM: To compare the peroperative blood loss and the postoperative systemic inflammatory reaction in patients receiving either a Vasculour II Albumin pre-impregnated prosthesis (VA group, n = 32) or a preclotted Vasculour II prosthesis (V group, n = 33) for elective surgery of the abdominal aorta. SETTING: University Hospital. DESIGN: Prospective, randomised study. METHODS: Peroperative blood loss was measured over two different periods: Phase I from the beginning of the operation to the completion of the proximal anastomosis, when blood loss cannot be related to the model of prosthesis implanted and phase II after the completion of the proximal anastomosis to the end of the operation. Postoperative blood loss was evaluated by the determination of the retroperitoneal drainage volume over a period of 2 days immediately following the operation. The presence of periprosthetic fluid was measured with echography at days 4, 9, 30 and 60. The postoperative systemic inflammatory reaction was evaluated by measuring the sedimentation rate and the C reactive protein levels daily from day 1 to day 9, and at days 14, 21, 28, 45, and 60, and by measuring the body temperature daily from day 1 to day 9. RESULTS: No significant differences of peroperative blood loss were observed. The same proportion of patients (35%) in both groups received homologous transfusion. The mean number of units of homologous blood transfused per patient was respectively 0.77 and 0.91 for the VA and the V group. The retroperitoneal drainage volume and the percentage of patients with periprosthetic fluid did not differ significantly. No significant differences in systemic postoperative inflammatory reaction were observed. CONCLUSION: There were no benefits in using albumin-impregnated prosthesis as opposed to preclotted prosthesis in terms of peroperative and postoperative blood loss, or by looking at the incidence of homologous blood transfusion. However, the glutaraldehyde cross-linked albumin did not induce any systemic inflammatory reaction.

Aged↗
PubMed2000

A short-term study in sheep with the Groningen temporomandibular joint prosthesis.

As part of the pre-clinical testing process of a newly developed temporomandibular joint (TMJ) prosthesis, animal experiments were performed. In 14 sheep, the right TMJ was replaced by the developed TMJ prosthesis. The prosthesis consisted of a skull part, a mandibular part and an intervening polyethylene disc. In the first series (6 sheep), three designs were tested, differing in the applied metal (stainless steel or titanium) and in the fitting method of the skull part (a fitting member or bone cement). The sheep were sacrificed after 8-16 weeks. In the second series (8 sheep), the preferred titanium fitting member design was applied, and the sheep were sacrificed after 2-10 weeks. One sheep was excluded because no correct position of the prosthesis parts could be achieved. At sacrifice, the removal torque of the screws was measured, and the surrounding tissues were harvested for histologic examination. The sheep recovered well and functioned until the end of the scheduled sacrifice date. Encountered problems were two disc dislocations, one fistula formation, and one screw failure. All mandibular parts were clinically stable, as were most skull parts with a fitting member, and one of both skull parts fitted with bone cement. The clinically observed stability was confirmed by the removal torque values, which indicated well-integrated screws. It is concluded that the TMJ prosthesis could remain stable and functional over the initial healing period. The main restriction of the sheep model is the much larger translatory capacity compared with patients, which adversely influences tissue healing.

Animals↗
PubMed2002

Survivorship of hip prosthesis in primary arthrosis: influence of bilaterality and interoperative time in 45,000 hip prostheses from the Finnish endoprosthesis register.

We studied the influence of bilaterality and interoperative time on survivorship of the hip prosthesis. The material consisted of 45,000 (3,153 bilateral) total hip arthroplasties and 38,000 patients operated on for primary osteoarthrosis, using data from the Finnish Endoprosthesis Register between 1980 and 1999. Cox regression analysis showed that male sex, young age, uncemented prosthesis and time of surgery (first 10-year period) were significant risk factors for aseptic loosening. We found no difference between the survivorship of the first bilateral and that of unilaterals, but second bilaterals survived better than the unilaterals. Bilateral prostheses survived better when the second prosthesis was implanted during the first postoperative year. The risk of loosening of a bilateral prosthesis increased when the second prosthesis was implanted a few years later. Survivorship of bilateral prosthesesin a 1-stage bilateral operation was about the same as in those operated on within the first postoperative year. Better survivorship of the second bilateral can cause bias in per hip survivorship analyses. In bilateral cases, the second hip should be operated on as soon as possible or be considered for a 1-stage bilateral procedure.

Aged↗
PubMed2003

A new problem-solving indwelling voice prosthesis, eliminating the need for frequent Candida- and "underpressure"-related replacements: Provox ActiValve.

OBJECTIVES: To develop and clinically assess a new prosthesis for voice rehabilitation after total laryngectomy that solves the problem of frequent Candida- and "underpressure"-related replacements. MATERIAL AND METHODS: We designed a voice prosthesis with a new valve mechanism, applying Candida-resistant fluoroplastic (Teflon-like) material for the valve and valve seat and magnets to generate an active closing force, preventing inadvertent opening of the valve during swallowing or deep inhalation. Several prototypes were tested in 13 laryngectomized patients and, subsequently, the final design was assessed in a prospective clinical trial in a cohort of 18 patients with a short device lifetime of their standard indwelling voice prosthesis (mean 30 days). RESULTS: Prototype testing and the long-term clinical trial confirmed that the new valve material remained free of Candida growth and that the use of magnets can prevent inadvertent opening of the valve during swallowing and/or deep inhalation. This resulted in a highly significant increase in device lifetime in the 18 laryngectomized patients in the prospective trial (14-fold increase on average, range 3-39-fold; p < 0.001). Lubrication with special medical-grade fluoridated silicone oil is favorable in patients who experience possible adhesion of the valve to the valve seat. CONCLUSIONS: This new voice prosthesis, the Provox ActiValve, represents a solution for patients who have the problem of requiring very frequent voice prosthesis replacements due to excessive Candida growth and/or inadvertent opening of the valve by swallowing and inhalation-related underpressure in the esophagus.

Adult↗
PubMed2005

Experimental study of an adjustable-length prosthesis in a temporal bone model.

CONCLUSIONS: This prosthesis has the advantage of rapid adjustment at the time of insertion in order to achieve optimal tension and, as a result, optimal sound transmission. OBJECTIVE: To test the acoustic performance of a new, adjustable incus replacement prosthesis in a human temporal bone model. MATERIAL AND METHODS: Experiments were performed in seven human temporal bones, before and after removal of the incus and insertion of the prosthesis. The input comprised 406 pure tones ranging in frequency between 0.1 and 10 kHz at an intensity of 80 dB SPL at the tympanic membrane. The output measurement was stapes footplate displacement, determined by means of a laser Doppler vibrometer. Three lengths of the prosthesis were investigated: optimal, optimal +0.2 mm and optimal +0.4 mm. RESULTS: The optimal-length prosthesis produced similar results to those of an intact middle ear. The slightly longer prostheses decreased middle ear sound transmission at all test frequencies, except those near 1.5 kHz.

Aged↗
PubMedDate not supplied

Total hip disarticulation prosthesis with suction socket: report of two cases.

A majority of hip disarticulations are performed in young people, with malignancy being the most common cause. The exoskeletal Canadian Hip Disarticulation prosthesis had been widely used as a standard total hip disarticulation prosthesis until recently when an endoskeletal modular version became the prosthesis of choice. However, the "basket-shaped" socket provided by the standard total hip disarticulation prostheses has been a source of discomfort and a reason for prosthetic rejection by many patients. This report concerns two patients with true lower limb disarticulation at the hip joint. Both of the patients failed to adapt to the standard total hip disarticulation prosthesis but successfully used a new total contact suction socket design. This new prosthesis provided improved suspension, better patient compliance, and enhanced prosthetic acceptance and mobility.

Activities of Daily Living↗
PubMedDate not supplied

End-to-side anastomosis using a new sutureless vascular prosthesis.

Performing a conventional vascular anastomosis during minimally invasive surgery remains a technically difficult and time-consuming task. The purpose of our study was to assess the efficacy of a new sutureless vascular prosthesis. Through a left thoracotomy, a short segment of the descending aorta was bypassed in eight sheep. Our Dacron prosthesis had a cuff at one extremity. The cuff was introduced into the artery through an arteriotomy and attached to the arterial wall with clips. Surgery was performed on the sheep again 12-15 weeks later, and the prosthesis was retrieved for macroscopic and microscopic examination. At surgery, insertion of the prosthesis was easy, fast, and safe. A 3-4 mm space between each clip was required for proper attachment. At the second surgery, all prostheses were completely patent and there were no anastomotic stenoses or aneurysms. This new sutureless vascular prosthesis was easy and safe in its placement and might prove useful for video assisted vascular aortic surgery.

Anastomosis, Surgical↗
PubMed1998

Quantifying risk of penile prosthesis infection with elevated glycosylated hemoglobin.

PURPOSE: Elevation of glycosylated hemoglobin above levels of 11.5 mg.% has been considered a contraindication to penile prosthesis implantation in diabetic patients. We determine the predictive value of glycosylated hemoglobin A1C in penile prosthesis infections in diabetic and nondiabetic patients to confirm or deny this prevalent opinion. MATERIALS AND METHODS: We conducted a 2-year prospective study of 389 patients, including 114 diabetics, who underwent 3-piece penile prosthesis implantation. All patients had similar preoperative preparation without regard to diabetic status, control or glycosylated hemoglobin A1C level. Risk of infection was statistically analyzed for diabetics versus nondiabetics, glycosylated hemoglobin A1C values above and below 11.5 mg.%, insulin dependent versus oral medication diabetics, and fasting blood sugars above and below 180 mg.%. RESULTS: Prosthesis infections developed in 10 diabetics (8.7%) and 11 nondiabetics (4.0%). No increased infection rate was observed in diabetics with high fasting sugars or diabetics on insulin. There was no statistically significant increased infection risk with increased levels of glycosylated hemoglobin A1C among all patients or among only the diabetics. In fact, there was no meaningful difference in the median or mean level of glycosylated hemoglobin A1C in the infected and noninfected patients regardless of diabetes. CONCLUSIONS: Use of glycosylated hemoglobin A1C values to identify and exclude surgical candidates with increased risk of infections is not proved by this study. Elevation of fasting sugar or insulin dependence also does not increase risk of infection in diabetics undergoing prosthesis implantation.

Diabetes Complications↗
PubMed1999

Ossiculoplasty in young children with the Applebaum incudostapedial joint prosthesis.

OBJECTIVE: To evaluate the performance of the Applebaum incudostapedial joint prosthesis in young children in terms of hearing results and long-term stability despite continuing eustachian tube dysfunction and otitis media. STUDY DESIGN: Retrospective review of all Applebaum prostheses placed in children at our institution from June 1993 to June 1998. RESULTS: In 1993 Applebaum proposed the use of a hydroxylapatite ossicular prosthesis as an alternative to incus interposition for the repair of incudostapedial discontinuity. We have used this prosthesis exclusively for the repair of such defects in children over the past 5 years. Among 12 operated ears, all healed, all prostheses remain in place (average duration, 2.6 y), and all children have excellent hearing (mean air-bone gap, 15 dB; range, 5-25 dB). CONCLUSIONS: The Applebaum incudostapedial joint prosthesis restores conductive hearing even in young children. It has been stable in the face of recurrent otitis media and has not interfered with revision surgery. Placement of the prosthesis at primary cholesteatoma surgery should be considered in children.

Adolescent↗
PubMed2006

Hypertrophic osteoarthropathy secondary to vascular prosthesis infection: report of 3 cases and review of the literature.

An infected vascular graft is an uncommon association in hypertrophic osteoarthropathy (HOA) but is important because of potential catastrophic complications. Here we describe 3 new patients with HOA secondary to vascular prosthesis infection and review the other 23 patients described in the English literature with this clinical syndrome. The finding of symptoms and signs of localized HOA in patients with arterial prosthesis may be the presenting manifestation of graft sepsis. In most patients the graft is located at the aorta or aortic bifurcation. The initial symptoms are fever, joint pain mainly involving the knees and ankles, clubbing, and in some cases intestinal bleeding. Recurrent abscesses and bacteremia arising in spite of appropriate antimicrobial therapy are prominent infectious signs. Another characteristic feature is the wide variety of bacteria isolated from a single patient. When a polymicrobial enteric flora is isolated from the blood or other tissue, an intestinal origin of infection can be readily suspected. Gallium or leukocyte scans are useful for detecting an abscess around the vascular prosthesis. In some cases, the detection of gas around the graft demonstrated by computed tomography is highly suggestive of prosthesis infection. Mechanisms involved in the pathogenesis of HOA associated with aortic graft infection are unknown. Treatment consists of intravenous antibiotics and surgical replacement of the infected graft. The prognosis of arterial prosthesis infection depends greatly on early diagnosis and treatment before the onset of life-threatening complications. Knowledge of this rare association may lead to an early diagnosis and appropriate management of this serious and often fatal complication.

Aged↗
PubMed2006

Outcome of penile prosthesis implantation for treating erectile dysfunction: experience with 504 procedures.

OBJECTIVE: To evaluate the outcome of penile prosthesis surgery for different types of prosthesis. PATIENTS AND METHODS: The notes of 447 men who had 504 penile prosthesis implanted between August 1975 and December 2000 were evaluated. Of the prostheses inserted, 393 were malleable, 81 were three-piece inflatable and 30 were self-contained hydraulic prostheses. The mean (range) age of the men was 52 (21-78) years; 404 men had primary implants and 43 had revision surgery after operations at other institutions. The mean follow-up was 50 (1-297) months. RESULTS: Of the 447 men, 22 were lost to follow-up immediately after surgery. The most serious postoperative complications were infection (8%) and erosion (5%), which was more common in diabetic patients (10%) and after pelvic trauma with a urethral injury (21%). Of 482 prostheses, 21 failed mechanically (4%) and revision surgery was needed for 5% of the prostheses inserted (24/482). Overall, 89% (377/425) of men could have sexual intercourse and 344 (81%) were satisfied with the results. CONCLUSIONS: Of the men implanted with a penile prosthesis, 81% were satisfied with the outcome and an even higher proportion were satisfied with the inflatable prostheses. Dissatisfaction was mainly due to complications that resulted in removal of the prosthesis.

Adult↗
PubMed1993

A new device for endothelial cell seeding of a small-caliber vascular prosthesis.

A device permitting homogeneous endothelial cell seeding of a small-caliber arterial prosthesis has been developed. The prosthesis is maintained firmly attached to a rotative scaffolding device. This device is activated by an electrical motor at constant and adjustable speed. The whole system is maintained at 37 degrees C in a cell culture incubator. The 4 mm internal diameter polytetrafluoroethylene (PTFE) prosthesis was coated with biological glue and seeded with human saphenous vein endothelial cells obtained by mechanical detachment. Cell seeding density was 2.10(4) cells/cm2 (Group A, n = 6) or 10(5) cells/cm2 (Group B, n = 6). Rotation speed was 8 revolutions per hour (rph) during 90 min. Analysis of the homogeneity of cell seeding was permitted by cell counts on five different segments of the prosthesis. Each longitudinal segment was analyzed at three different subsegments of the circumference. The average adhesion was 43 +/- 4% in Group A and 38% +/- in Group B of seeded cells. No difference could be observed between the different segments and subsegments. In the two groups, cells were spread, and in Group B, a complete endothelial cell layer was obtained on the graft surface. This study permits validation of the device to allow homogeneous cell seeding in an arterial prosthesis.

Blood Vessel Prosthesis↗
PubMed2006

Preservation of existing inflatable penile prosthesis pump mechanism during scrotal surgery.

INTRODUCTION: There is little reported regarding the feasibility of scrotal surgery in patients with an existing penile prosthesis. We report a series of two patients with existing inflatable penile prostheses who underwent scrotal surgery for unrelated indications in which the prosthesis pump mechanism and tubing were preserved. In both instances, damage to the prosthetic pump and tubing were avoided. AIM: To demonstrate two instances where scrotal surgery was performed successfully in the setting of a pre-existing penile prosthesis. METHODS: Two cases of patients with existing penile implant who underwent scrotal surgery for pathology unrelated to the implant are reported. CONCLUSIONS: It is possible to perform scrotal surgery in a patient who has an existing penile prosthesis without injuring or infecting the prosthesis.

Aged↗
PubMed1987

Self-expanding endovascular prosthesis: an experimental study.

A new type of endovascular prosthesis was inserted in 28 animals and evaluated for several factors, including thrombogenicity, tendency to migrate, critical implant zones, and incorporation into the vascular wall. The new prosthesis is a woven, multifilament structure of stainless steel alloy; its inherent elastic, self-expanding characteristics hold it against the vessel walls. Forty-seven endoprostheses (3-5 mm in diameter, 15-50 mm long) were percutaneously implanted with either a 6-F introducer sheath, a coaxial 9-F catheter, or a 0.014-inch (0.036-cm) guide wire into the femoropopliteal, coronary, carotid, and renal arteries and iliac veins. Anticoagulant or platelet antiaggregating agents were not used before or after implantation. Angiographic and histologic analyses showed that the prosthesis had a very low thrombogenicity when it was well adapted to the native vessel diameter and that it was incorporated into the vessel wall by a new intima by the 3d week after implantation. No migration occurred, and branch vessel flow was preserved even in those vessels in which ostia were traversed by the prosthesis. This prosthesis has potential for clinical application in the treatment of postangioplasty restenoses, particularly in the coronary arteries.

Animals↗
PubMed1989

Mitral prosthesis malfunction. Comparative Doppler echocardiographic studies of mitral prostheses before and after replacement.

To assess the influence of mitral prosthesis malfunction on various Doppler echocardiographic indexes, we studied the changes in the peak mitral flow velocity during early diastolic filling phase (Vmax), the mean transprosthesis pressure drop from the simplified Bernoulli equation, the mitral valve area by the pressure half-time method, and the left ventricular isovolumic relaxation time in 15 patients before and after replacement of the malfunctioning mitral prosthesis using continuous wave Doppler echocardiography. Examination of the 15 replaced prostheses revealed a torn or perforated leaflet in 12 valves and a sewing ring dehiscence in one valve. Additional restricted leaflet motion (classified as mild obstruction) was seen in three of these 13 valves. In the remaining two valves, severe prosthesis obstruction was noted. Changes in the Doppler indexes between the preoperative and postoperative study were present in all patients regarding Vmax (mean, 2.2 +/- 0.3 versus 1.6 +/- 0.2 m/sec; p less than 0.001), mean gradient (mean, 9 +/- 5 versus 5 +/- 0.8 mm Hg; p less than 0.001), and isovolumic relaxation time (mean, 47 +/- 12 msec versus 80 +/- 13 msec; p less than 0.001). The mean mitral valve area remained virtually unchanged (2.3 +/- 0.9 versus 2.6 +/- 0.3 cm2; p = NS) but increased postoperatively in each patient with preoperative mild or severe prosthesis obstruction without concomitant aortic regurgitation. Our conclusion is that the peak mitral flow velocity, the mean gradient, and the isovolumic relaxation time are useful parameters in the differentiation of normal and abnormal mitral prosthesis function but may not define the underlying lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Parametric modelling of a knee joint prosthesis.

This paper presents an approach for the establishment of a parametric model of knee joint prosthesis. Four different sizes of a commercial prosthesis are used as an example in the study. A reverse engineering technique was employed to reconstruct the prosthesis on CATIA, a CAD (computer aided design) system. Parametric models were established as a result of the analysis. Using the parametric model established and the knee data obtained from a clinical study on 21 pairs of cadaveric Asian knees, the development of a prototype prosthesis that suits a patient with a very small knee joint is presented. However, it was found that modification to certain parameters may be inevitable due to the uniqueness of the Asian knee. An avenue for rapid modelling and eventually economical production of a customized knee joint prosthesis for patients is proposed and discussed.

Asian People↗
PubMed1989

The movements of the components of the Hastings bipolar prosthesis. A radiographic study in 65 patients.

We aimed to find out whether the Hastings bipolar prosthesis moved in a bipolar fashion after its use for displaced fractures of the femoral neck. In 65 patients non-weight-bearing movement was assessed radiographically and compared with an earlier study of the Monk prosthesis. In 70% of patients, the only movement was between the acetabulum and the prosthetic shell, the prosthesis behaving as if it were unipolar. This did not change with time, but there was a slight improvement in the range of movement, particularly in flexion. The absence of movement between the outer shell and the metal head is most probably due to the design of the prosthesis and makes this prosthesis unsuitable for use in osteoarthritic hips.

Aged↗
PubMed2004

Influence of humeral prosthesis height on biomechanics of glenohumeral abduction. An in vitro study.

BACKGROUND: During shoulder replacement surgery, the normal height of the proximal part of the humerus relative to the tuberosities frequently is not restored because of differences in prosthetic geometry or problems with surgical technique. The purpose of the present study was to determine the effect of humeral prosthesis height on range of motion and on the moment arms of the rotator cuff muscles during glenohumeral abduction. METHODS: Tendon excursions and abduction angles were recorded simultaneously in six cadaveric specimens during passive glenohumeral abduction in the scapular plane. Moment arms were calculated for each muscle by computing the slope of the tendon excursion-versus-glenohumeral abduction angle relationship. The experiments were carried out with the intact joint and after replacement of the humeral head with a prosthesis that was inserted in an anatomically correct position as well as 5 and 10 mm too high. RESULTS: Insertion of the prosthesis in positions that were 5 and 10 mm too high resulted in significant and marked reductions of the maximum abduction angle of 10 degrees (range, 5 degrees to 18 degrees ) and 16 degrees (range, 12 degrees to 20 degrees ), respectively. In addition, the moment arms of the infraspinatus and subscapularis decreased by 4 to 10 mm. This corresponded to a 20% to 50% decrease of the abduction moment arms of the infraspinatus and an approximately 50% to 100% decrease of the abduction moment arms of the subscapularis, depending on the abduction angle and the part of the muscle being considered. CONCLUSIONS: If a humeral head prosthesis is placed too high relative to the tuberosities, shoulder function is impaired by two potential mechanisms: (1) the inferior capsule becomes tight at lower abduction angles and limits abduction, and (2) the center of rotation is displaced upward in relation to the line of action of the rotator cuff muscles, resulting in smaller moment arms and decreased abduction moments of the respective muscles. CLINICAL RELEVANCE: In patients managed with shoulder replacement surgery, limitation of range of motion, loss of abduction strength, and overload with long-term failure of the supraspinatus tendon are potential consequences of positioning the humeral head of the prosthesis proximal to the anatomic position.

Analysis of Variance↗