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PubMedDate not supplied

[Rupture of the teflon cover of valvular prosthesis in aortic position. Severe postoperative complication].

Fourteen patients (18.5%) are presented from a total of 78 patients who received a Starr-Edwards prosthesis Model No. 2320 with a Telfon covering, in an aortic position. In the late post-operative period these patients developed complications which merited a surgical reintervention. Twelve of these were operated on to substitute this prosthesis for a distinct type and model. In the other two the teflon covering on the cage of the prosthesis was dried thoroughly. The most frequent complication which made it necessary to reoperate was hemolysis, which would not cede to intense medical treatment. The hemolysis appeared at an average of 20 months post-operatively. In all of the cases we found a rupture due to erosion of the telfon material. This is undoubtably an etiological factor of the hemolysis. Eleven of the 14 cases (78.5%) survived. Ten of which were possible to follow up on a long term basis. Seven of these (70%) are asymptomatic and the remaining 3 (30%) are evolving with data suggestive of peri-prosthetic aortic insuficiency. A review is made of the evolution of Starr-Edwards prosthesis and the causes of the post-operative hemolysis in valvular surgery.

Adolescent↗
PubMed1982

The results of early clinical trials with a microporus coated metal hip prosthesis.

In an attempt to find a better method of attaching a prosthesis to bone, a microporous coating system, with a pore width of approximately 50 microns was chosen for evaluation. A microporous coated Austin-Moore type prosthesis was inserted into 34 patients, and the results were studied for a three-year period. Four cases required reoperations, and ten cases demonstrated radiolucent lines around the prosthesis suggesting that bone ingrowth had not occurred. This article analyzes the reasons for failure of ingrowth and suggests modifications in the prosthesis design and postoperative management that hopefully will be effective.

Adult↗
PubMed1982

The Marmor knee prosthesis: long term results in 135 cases.

The authors report the results of clinical and radiological follow up examinations carried out between six months and four years after the insertion of Marmor knee prostheses in 135 patients (ninety-three with rheumatoid arthritis and forty-two with osteoarthrosis) operated on at the Orthopaedic Clinic of the University of Uppsala between 1975 and 1979. The results were very good and the few complications that arose were easily resolved. The authors have therefore adopted the Marmor prosthesis for routine use. The only valid alternative to this type of prosthesis is the spherocentric prosthesis, which was applied after failures with the Marmor or other types of prosthesis, in cases involving varus or valgus deformity exceeding 30 degrees, and in cases of severe bone destruction.

Adult↗
PubMed1981

[Diagnosis of the failure and thrombosis of a mitral valve prosthesis based on indirect study methods].

The possibilities of phono- and polycardiography in the diagnosis of failure and thrombosis of a mitral valve prosthesis are demonstrated. It is established that the most characteristic phonocardiographic signs of paravalvular failure in patients with this pathological condition are a systolic murmur, a reduced second sound-sound of mitral valve prosthesis opening interval and ejection period (according to the findings of polycardiography) and prolongation of the Q-first sound interval. In typical cases, thrombosis of a mitral valve prosthesis is attended by a diastolic murmur, a reduced second sound-sound interval of prosthesis opening, and prolongation of the Q-first sound interval.

Electrocardiography↗
PubMed1981

[Echocardiographic features of the St. Jude Medical valve prosthesis (author's transl)].

The St. Jude Medical (SJM) valve is a new low-profile bileaflet prosthesis with central flow, low transvalvular gradients and low thrombogenicity. Echocardiographic features of 212 correctly functioning SJM prostheses implanted in 160 patients were studied. A SJM prosthesis echogram is unique for the presence of echoes from two hemidisks that come together when the valve opens and separate when the valves close. The movement of the two hemidisks is not always synchronous. A little asynchronism (less than 0.01 sec.) is possible as the valve begins to open. More pronounced asynchronisms are recorded in prostheses implanted in mitral position and specially when the R-R interval is longer than 1 sec. In this case partial or definitive mid-diastolic closure of the posterior hemidisk is frequent. On the contrary the anterior hemidisk always remains in maximum open position for the complete duration of the diastole. Opening and closing velocities of the valve are extremely variable. However, opening velocity, independent of where the prosthesis is implanted, is always slower than the closing one. The opening valve interval is 0.06-0.10 sec. in mitral position and 0.03-0.05 sec. in aortic position. Echocardiography is a very useful diagnostic tool for evaluating the efficiency of SJM prosthesis. Data obtained from echograms of prostheses implanted in mitral position prove that the inertia of the valve hemidisks is similar to that of natural valve leaflets.

Aortic Valve↗
PubMed1978

The small-carrion penile prosthesis.

A normal state of erection can be achieved by bilateral, intracorporal implantation of the Small-Carrion penile prosthesis. This prosthesis gives adequate length and, more importantly for normal intercourse, normal width to the penis. Although the prosthesis is firm, it is flexible enough to keep the phallus inconspicuous under various types of undershorts, either in the normal position or against the abdominal wall. The fact that the patient will have a permanent erection has not been a deterrent. Furthermore, there have been no complaints about this postoperatively. Raz and Kaufman, Goodwin, Melman, Nellens et al., and others have reported excellent results with the use of the Small-Carrion prosthesis.

Erectile Dysfunction↗
PubMed1980

Results with the constrained total knee prosthesis in treating severely disabled patients and patients with failed total knee replacements.

Fifty-fix constrained total knee replacements (forty Guepar and sixteen Herbert prostheses) were performed in forty-nine severely disabled arthritic patients and they were followed for two to four years. Seventeen of these knees were operated on to salvage a failed prosthesis. Good relief of pain was achieved in 64 per cent of the knees but there was less improvement in walking and function. The over-all range of motion increased because of a reduction in preoperative flexion contractures. The results in the salvage group were less successful than in those patients who underwent a primary operation. Between six months and one year postoperatively, pain had developed in 17 per cent of the fifty-six knees, 9 per cent had walking difficulties, and 7 per cent lost function. Patellofemoral pain accounted for the unfavorable pain ratings in over half of the knees. Zonal roentgenographic analysis of each knee indicated high incidences of radiolucent lines at the cement-bone interface (75 per cent), cement-metal lucencies (68 per cent), and cement deficiencies (73 per cent). Forty-three per cent of the knees showed excessive posterior placement of the prosthesis of more than five millimeters, resulting in flexion contractures of as much as 5 degrees. Complications requiring reoperation developed in nine knees (16 per cent). There was one case of loosening and three knees had deep infections. Chronic postoperative effusions were present in 48 per cent of the knees. The use of either a cemented metal-on-metal hinged knee replacement or a metal-on-polyethylene hinge type of prosthesis was found to result in a relatively high incidence of failures and complications, and did not solve the problem of treating patients with a failed knee prosthesis.

Adult↗
PubMedDate not supplied

Circumferential and axial strain in the proximal femur: effect of prosthesis type and position.

Because the Charnley-Müller prosthesis inserted in a varus position has been found subject to loosening, circumferential and longitudinal strain patterns were determined in proximal cadaver femora that had been instrumented with strain gauge rosettes and implanted with total hip replacement femoral prostheses. Both Charnley and Charnley-Müller prostheses were inserted in the varus, valgus, and neutral positions. An intact femur was similarly studied. Strain patterns in the test femora were altered by implant insertion, mainly by reducing longitudinal strain. Prosthesis type did not alter strain patterns but prosthesis position did. Valgus position produced compressive axial strain laterally and tensile strain medially at the tip of the prosthesis which was the reverse of that seen with varus position. Valgus position produced biaxial compressive strain at the medial calcar whereas varus position produced circumferential tension and axial compression at that location.

Biophysical Phenomena↗
PubMed1995

Aortic valve prosthesis and late survival of successfully repaired type A dissection.

Seventy-two operative survivors of acute type A dissection between 1973 and 1993 had a complete follow up with a 16 years actuarial survival of 57% and a reoperation free actuarial survival of 34%. Follow up was 100% complete and covered a total of 500.6 patients-years with a median of seven years. Distal tear location (proximal, medium or distal aortic arch) with retrograde dissection toward the aortic valve was the single most important predictor of late mortality with a relative risk of 4.4 (70%CL 2.4-8.2) (p = 0.016). Mortality rate of patients with an aortic valve prosthesis was 6.2%/patient-year vs. 1.7/patient-year without aortic valve prosthesis, with a relative risk of 3.4 (70%CL 2.0-5.8) (p = 0.02). This finding could be due to confounding of variables related both to death and need of aortic valve replacement. Therefore a multivariate proportional hazard analysis, with mandatory inclusion of possible confounders, was done. It showed that patients with aortic valvular prosthesis had eight times higher risk (70% CL 2.7-24.2); prosthetic aortic valves and conservative aortic root procedures had an unconfounded relative risk of 14 times higher (70%CL 3.4-58.7) (P = 0.06), whereas patients with a composite conduit had a six times higher risk (70%CL 2.0-19.9) (p = 0.11). These findings support the attitude favoring a selective approach to aortic root repair and oppose standardized use of aortic valve prosthesis or composite conduit in acute type A dissection.

Adolescent↗
PubMedDate not supplied

[Anastomotic aneurysm following insertion of aorto-iliac or aorto-femoral prosthesis. Treatment and long-term results].

This retrospective study was conducted to evaluate the long-term results obtained after treating anastomotic false aneurysm occurring after implantations of aorto-iliac or aorto-femoral prostheses in order to identify optimal treatment. During a 20-year period, 66 anastomotic aneurysms were discovered and treated in 48 patients. The mean delay after initial surgery was 6.3 years. Locations observed were femoral (n = 58) aortic (n = 6) and iliac (n = 2). Five aneurysms were revealed by an acute ischaemia, three others by bleeding and one by abdominal pain. The 57 others were diagnosed in an equal proportion either during physical examination or periodic imaging. Aortic and iliac aneurysms were treated by complete or partial replacement of the prosthesis. There were two urinary fistulas, one being fatal and one recurrent haemorrhage followed by death. Femoral aneurysms were treated in 4 out of 5 cases by interpositioning a prosthesis and in 1 out of 5 cases by simple resuturing. There was one fatal cerebral haemorrhage, 4 cases of early thrombosis and 6 cases, of recurrent anastomotic aneurysm (10%). The clinical course required amputation in 3 patients. In this series, the overall outcome was satisfactory. For aneurysms of aortic or iliac anastomoses, one must avoid dissecting the prosthesis-ureter crossover and blind extraction of a branch which can lead to urinary fistulas. For femoral anastomoses, the following recommendations are important: conservation of the collaterals, suturing deeply into healthy tissue and interposition of a new prosthesis in case of tension. Cases of recurrent aneurysm are rare and should be treated with the same careful procedures.

Aged↗
PubMed1994

[Posterior luxation of the tibia on total knee prosthesis: apropos of 6 cases].

PURPOSE OF THE STUDY: Posterior dislocation of Total knee arthroplasty is an infrequent but serious complication. Six cases of this complication were treated from 1979 to december 1993, all occurring on primary arthroplasties. MATERIAL AND METHODS: Knee arthroplasty was performed once for rheumatoid arthritis, five times for osteoarthritis. All cases occurred with a semi constrained prosthesis sacrifying posterior cruciate ligament: 2 Total condylar without posterior stabilisation, and 4 posterior stabilised prosthesis. In one case the dislocation occurred on a very severe rheumatoid arthritis: the patient, confined in a wheel chair, was not reoperated. In two patients, the dislocation was due to rotatory malposition of the tibial component. In the last three cases, we did not found any cause to the dislocation, except ligament laxity: 2 of these patients had, pre operatively, a valgus deformity. In 6 cases, we found only 2 problems on extensor system (one patellar dislocation and one patellectomy). RESULTS: 5 patients required a surgical treatment In 2 cases, we used a more constrained prosthesis, with poor results, but the knee was stable. Once, by changing the position of the tibial component, and using a thicker plate. In 2 patients we only put a thicker tibial polyethylene component. These 3 patients had a good stability: 2 have an excellent result with H.S.S. rating system, the third one has a poor result explained by patellar pseudoarthrosis occurring after traumatic patellar fracture. DISCUSSION: With our patients and cases published in North American works, we have studied the different mechanisms of such a posterior dislocation: rotatory disorder on tibial component, ligament laxity in flexion, extensor system deficiency, valgus deformity with important postero lateral release. CONCLUSION: The causes of posterior dislocation on Total knee arthroplasties must be known: we have to try to prevent such a complication. If it occurs, a precise analysis will permit a logical curative treatment, which must avoid constrained prosthesis.

Aged↗
PubMed1994

[Possibilities for quantitative gait analysis in evaluation of prosthesis fit].

Nowadays, the fitting of a lower-limb prosthesis is done mainly on an empirical basis. The main aim of the present study was to provide objective data and presentations to support the subjective data. With the aid of a cybernetic statement, the process of fitting a prosthesis to a human subject was developed as a self-optimizing control cycle. Using this systematic scheme, the walking trial was identified as the process element of this control cycle in which the fitting proper took place. Starting with this systematic scheme, the characteristics of defined changes to the system human-prosthesis during walking were measured with the aid of a specially configured gait analysis system. For the estimation of the characteristics of the measured walking trial, a three stage parameter system based initially only on the angle, velocity and acceleration curves at the knee joint was developed. On the basis of pattern recognition routines, the parameter system permits a very high level of identification of the measurements. The identification of poor fittings not covered by the pattern recognition system is not yet satisfactory. However, with the incorporation of additional gait parameters, it will be possible to further improve the description of the gait, enabling better recognition of disturbances in the human-prosthesis system.

Artificial Limbs↗
PubMed1994

[Primary treatment of unstable pertrochanteric femoral fractures using a head-neck prosthesis in elderly patients].

OBJECTIVE: Evaluation of the treatment of unstable pertrochanteric femoral fractures with a femoral head prosthesis in older patients. DESIGN: Descriptive. SETTING: University Hospital Nijmegen, the Netherlands. METHOD: From January 1988 through December 1992, 15 patients with 15 unstable pertrochanteric femoral fractures were treated with a femoral head prosthesis and additional wiring of the trochanter. The group consisted of 11 women and 4 men with a mean age of 86 years. Two operations were secondary treatments after broken angled-plate fixation. The other 13 were primary treatments. RESULTS: A stable fixation allowing weight-bearing was achieved in all cases. The operations were accompanied by high morbidity and mortality rates: 4 patients died within 3 months after surgery. One dislocation of the prosthesis occurred. Twelve fractures consolidated, pseudarthrosis of the greater trochanter occurred twice. Five patients regained their preoperative walking ability. CONCLUSION: Femoral head prosthesis with additional wiring is an alternative with few mechanical complications in the treatment of unstable pertrochanteric femoral fractures.

Aged↗
PubMed1994

[Doppler echocardiographic evaluation of the new mechanical bileaflet Sorin Bicarbon valve prosthesis compared with St. Jude Medical].

BACKGROUND: Despite the Bicarbon valve has been marketed for more than two years, no systematic Doppler evaluation of its normal functioning has yet been published. Therefore, the aims of this study were to establish the normal flow characteristics for the Bicarbon bileaflet prosthetic heart valve and to compare them with those obtained from the St. Jude Medical valve prosthesis. METHODS: Doppler echocardiographic characteristics of normally functioning Bicarbon prostheses were prospectively assessed in 76 consecutive patients (44 males and 32 females, mean age 60 +/- 10 years) with 79 valves in mitral (n = 29) and aortic (n = 50) position whose function was considered normal by clinical and echocardiographic evaluation. In addition, Doppler characteristics of the Bicarbon valves in aortic position were compared to those of 27 normal functioning St. Jude Medical implanted during the same period. RESULTS: For the mitral valve prostheses, we found non significant difference among prosthesis sizes in terms of transprosthetic gradients or pressure half time. Peak and mean gradients were similar in the 27-mm and 31-mm size valves (from 11 +/- 4 to 11 +/- 2 mm Hg and from 5 +/- 2 to 5 +/- 1 mm Hg, respectively; p = NS for both). Similarly, the pressure half time was similar in the 27-mm and in the 31-mm size valve (85 +/- 16 and 76 +/- 13 msec; p = NS). Conversely, for the aortic valve prostheses, there was a significant decrease in transprosthetic gradients and an increase in effective orifice areas as prosthesis size increased. Mean gradient was 13 +/- 1 mm Hg in 19-mm size valves, and it decreased to 6 +/- 2 mm Hg in the 29-mm size. Effective prosthetic valve area calculated using the continuity equation, ranged between 1.0 +/- 0.3 cm2 for 19-mm size valves to 3.5 +/- 0.7 cm2 for 29-mm size. With analysis of variance, effective prosthetic aortic valve area differentiated various valve sizes (F = 23.3; p < 0.0001) better than peak (F = 3.2; p = 0.017) or mean (F = 4.19; p = 0.0035) gradients alone did. Furthermore, effective prosthetic aortic valve area correlated better than peak and mean gradients with prosthetic size (r = 0.87, r = -0.58 and r = -0.57; respectively). In addition, peak and mean transprosthetic gradients and effective prosthetic aortic valve areas did not show any statistically significant difference between the Bicarbon and the St. Jude Medical valves in aortic position, either in 19 and 21 mm (25 +/- 8 mm Hg, 13 +/- 4 mm Hg, 1.3 +/- 0.3 cm2 and 32 +/- 11 mm Hg, 17 +/- 6 mm Hg, 1.2 +/- 0.4 cm2, respectively; p = NS), or in 23 and 25 mm (21 +/- 8 mm Hg, 11 +/- 4 mm Hg, 2.1 +/- 0.5 cm2 and 24 +/- 11 mm Hg, 12 +/- 5 mm Hg, 1.8 +/- 0.4 cm2, respectively; p = NS) or in 27 and 29 mm (12 +/- 2 mm Hg, 7 +/- 1 mm Hg, 2.8 +/- 0.9 cm2 and 16 +/- 5 mm Hg, 7 +/- 2 mm Hg, 2.6 +/- 0.4 cm2, respectively; p = NS). CONCLUSIONS: This study suggest that the Bicarbon valve prosthesis offers relatively little resistance to forward flow except at a small anulus diameter. Furthermore, these is no statistically significant difference between the Bicarbon and the St. Jude Medical in aortic position with regard to early hemodynamic performances.

Aged↗
PubMed1994

Sudden death in a large prosthetic valve series based on a single prosthesis: experience with the medtronic Hall valve.

In order to test the validity of the current guidelines on the categorization of non-autopsied sudden death after valve replacement, a detailed analysis was undertaken of 412 deaths in a large single-institution prosthetic series based on one type of prosthesis (Medtronic Hall) over a 13-year period. Of 69 sudden or unwitnessed deaths, 48 (70%) were autopsied. There were no sudden deaths specifically related to the prosthesis itself, 79% of deaths were due to coronary disease or left ventricular dysfunction and 10% were due to intracranial hemorrhage. Overall, 90% of sudden deaths were unrelated to the prosthesis A seasonal fluctuation in the incidence of sudden and unwitnessed deaths was demonstrated in keeping with the known epidemiology of sudden death in the general population. It was concluded that there was no evidence to support the recommendation that all non-autopsied sudden deaths should be attributed to the prosthesis.

Cerebral Hemorrhage↗
PubMed1976

[Long-term results of aortic valve replacement with a prosthesis].

A long term evaluation of prosthetic replacement of the aortic valve by various types of prosthesis has been carried out; 530 patients from various centres of cardiology were studied. The average annual mortality after the first two postoperative years was about 2.5% and half of the patients undergoing surgery were still alive after 10 years. The functional improvement is usually marked and is generally to be expected, although with an increased risk, even in patients who underwent surgery at stage IV of the NYHA classification. In this study, the prostheses which were associated with the best long term results were the Starr-Edwards 1260, the Smeloff-Cutter, and the Björk. The commonest complications after the first month were dehiscence of the prosthesis (11.8%), thromboembolic episodes (11.2%), coronary complicatons (11.1%) and cardiac failure (7.1%). The most serious is infection of the prosthesis, which is almost invariably fatal. Deterioration in the substance of the prosthesis has become very rare, but there must be reservations in this respect with the SE2400, which has still not been in use long enough. Revision operations were carried out on 7.6% of the survivors at one month, with a mortality of 18.4%. Sudden death remains a constant threat. A study of the actuarial survival graphs for operated and non-operated cases shows that surgery should be advised in all poorly tolerated valve defects, and even for an uncomplicated tight aortic stenosis. Bearing in mind the progressive lowering of operative mortality, surgical treatment is also justified in cases with marked or gross aortic incompetence which is well tolerated if flow-up studies show a progressive increase in cardiac volume.

Aortic Valve↗
PubMedDate not supplied

[Rupture of posterior wall of the left ventricle after mitral valve prosthesis].

Rupture of the posterior wall of the left ventricle is a comparatively rare complication occurring after prosthesis of the mitral valve, but resulting in high mortality. There is a great diverse of opinions regarding the causes of this complication. The likely causes are surgical injury and the used method for prosthesis. The authors studied 9 patients with rupture of the posterior wall of the left ventricle following mitral prosthesis. In all patients the prosthesis was carried out by the routine procedure by dissecting the two mitral cusps with subvalvular structures. Two (22%) patients survived after defect plasty. The above surgical policy is the most effective to control bleeding and achieve a favourable result of correction of this complication.

Adult↗
PubMed1993

Biventricular repair of cardiac isomerism with common atrioventricular canal with the aid of an endocardial cushion prosthesis.

Between 1983 and 1990, six patients with atrial isomerism associated with common atrioventricular canal and double-outlet right ventricle were operated on with the aid of an endocardial cushion prosthesis. This prosthesis, which has been used for the repair of common atrioventricular canal since 1975, is composed of a vertical Dacron patch and "wings" constructed from the patient's own pericardium, which are attached to both sides of the patch to compensate for the defective atrioventricular valve tissue. The ventricular portion of the patch was extended anteriorly to construct the route for blood flow from the left ventricle to the aorta. Intraventricular repair was performed through the common atrioventricular orifice in all patients and also through an additional right ventriculotomy in one patient. The complex systemic and pulmonary venous return was separated by use of the atrial part of the endocardial cushion prosthesis together with additional prosthetic materials. All patients survived the operation and were followed up from 1 to 9 years. All of them are doing well, although one patient has a significant interventricular residual shunt. Repair of atrial isomerism with common atrioventricular canal and double-outlet right ventricle with an endocardial cushion prosthesis was performed with satisfactory immediate and intermediate-term postoperative results.

Blood Vessel Prosthesis↗