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At least 559 records · Page 31Linked to original sources
PubMed1977

Silicone lymphadenopathy and synovitis. Complications of silicone elastomer finger joint prostheses.

We report two complications of silicone elastomer finger joint prostheses. In one patient, the prostheses broke, with silicone particles present in synovium ("detritic synovitis"). In another patient, silicone particles were found in an axillary lymph node five years after insertion of prostheses in the ipsilateral hand (prostheses were intact at the time). Microscopically, silicone particles in synovium and lymph node were identical to particles abraded from a new prosthesis.

Arthritis, Rheumatoid↗
PubMed1988

Semiconstrained elbow prostheses with special reference to the GSB III prosthesis.

Fully constrained metal-to-metal elbow prostheses are not used anymore because of a high loosening rate. Today semiconstrained or condylar prostheses are the two possibilities when replacement of a destroyed elbow joint is considered. A careful analysis of the most recent publications in the world literature reveals a high complication rate for both types of prostheses, each one having specific advantages and disadvantages. The Gschwend-Scheier-Bähler (GSB) III prosthesis is a semiconstrained prosthesis, requires little bone resection, and is therefore easily salvaged. The results in regard to pain relief and improvement in range of motion are satisfactory in a high percentage of patients. The rate of lasting complications is lower than with most of the other prostheses. The authors' transtricipital approach is also a factor that contributes to the high success rate. In case of a failed arthroplasty the authors' method of reconstructing the humeral condyles allows a better salvage.

Adult↗
PubMed1978

[On the usefulness of bone scintigraphy for detecting loosening of articular prostheses (author's transl)].

The most important complication of articular substitution is the loosening of the prostheses as a result of permanent overstraining, trauma, chemical or infectious noxae. The value of bone scintigraphy in the diagnosis of loosening of the endoprothesis was examined in 53 articular prostheses (49 hip joints and 4 knee joints). A pathological scan was evident in all cases where the prosthesis had become loose (18 cases), whereas a normal scan was found in 34 firmly positioned prostheses. A false positive scan occurred in one case of periarthritis. Bone scintigraphy can be employed as a means of diagnosing loosening of prostheses after a period of nine months following the operation; up to that time, enhancement can be due to the operation. A positive scan in case of loosening of the prosthesis is manifested earlier than radiological signs. For this reason, scintigraphy can be recommended as a routine examination method in pain after articular substitution surgery.

Bacterial Infections↗
PubMed1987

[Are auditory prostheses a contraindication to magnetic resonance imaging?].

Prior to the use of nuclear magnetic resonance imaging (NMRI) in patients with metallic ossicular prostheses their compatibility must be investigated with the intense magnetic fields generated by NMRI. Implanted auditory prostheses are an absolute contraindication to NMRI, but an experimental study of its possible interaction with metallic stapedial prostheses has shown absence of their displacement. The artefact induced may alter images of middle ear but do not affect internal auditory canal. Nevertheless, manufacturers should conduct tests of magnetism of prostheses before they are passed as satisfactory.

Cochlear Implants↗
PubMed1985

[Experimental studies of vascular prostheses made of plastics with antibacterial properties].

Bilaterally velour, polyester vascular prostheses were soaked with antibiotics: vibramicin, gentamicin and riphamicin. To obtain more stable binding of the prostheses with the antibiotics, physico-chemical modification of its surface was made. The prostheses retained their bacteriocidal properties even after 120 hours of being in the arterial system of a dog. Experiments of animals show the prostheses are effective in fighting back experimental infection.

Animals↗
PubMed1985

[Hemolysis in patients with heart valve prostheses. Comparison between Björk-Shiley and Saint-Jude Medical valves].

The problem of haemolysis was studied in 244 patients with one or two prosthetic heart valves: 232 of these patients had normal valve function as assessed by clinical examination, radioscopy and echocardiography; 112 patients had a Bjork-Shiley (BS) prosthesis, 25 in the aortic position (BSA), 71 in the mitral position (BSM) and 16 in both aortic and mitral positions (BSA + M). These patients were operated between July 1979 and January 1981. One hundred and twenty other patients had Saint Jude medical (SJM) prostheses; 48 in the aortic position (SJMA), 44 in the mitral position (SJMM) and 28 in both aortic and mitral positions (SJMM + A). These patients were operated between January 1982 and July 1983. Twelve patients (operated between 1977 and 1984) had prosthetic valve dysfunction confirmed by angiography or anatomically (SJM = 7); BS = 5). The plasma haemoglobin concentration (pHb) was used as the reference: it was measured by spectrophotometry with a sensitivity of 0.5 mg/100 ml. There was no significant difference the SJM and BS groups at surgery (BS: 4.62 mg/100 ml; SJM: 4.31 mg/100 ml). In the absence of prosthetic valve dysfunction, haemolysis was significantly greater (p less than 0.001) in the SJM (8.28 mg/100 ml) than in the BS (3.08 mg/100 ml). No statistical correlation was observed with the severity of cardiac disease, the aortic or mitral position of the prostheses or with the number of prostheses. Haemolysis was subclinical in all cases. When haemodynamically significant prosthetic valve dysfunction was present, haemolysis was inconstant in BS prostheses (2 out of 5 cases) despite major haemodynamic disturbances in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

[Thromboembolic accidents in patients with mechanical prostheses and heterografts].

759 patients with a prosthetic valve replacement (335 mitral prostheses, 184 aortic prostheses and 240 double or triple valve replacements) were regularly followed-up for a total duration of 3 715 patient years. The mean age of these patients was 30 years. 681 (90%) of these patients were treated by long term anticoagulants, which were effective in only 320 patients. 78 patients did not receive anticoagulant treatment. 97 patients presented a total of 129 thrombo-embolic episodes (TEE), i.e. a frequency of 12.7 p. cent or 3.4 embolisms per 100 patients-year. The rate of TEE was influenced by the site of the prosthesis and by the presence or absence of complete arrhythmia due to atrial fibrillation, but it was not influenced by the quality of the anticoagulant treatment. In the patients with a heterograft, the rate of TEE varied according to the site of the prosthesis. In the aortic position, the rate of TEE in our series of prostheses was essentially similar to that reported in series of heterografts by Davila, Oyer and lonescu. This rate is generally higher for the mechanical prostheses in the mitral position and in the case of double valve replacement. The aim of this study was to deduce the current operative indications in relation to the choice of the type of valve replacement.

Adolescent↗
PubMed1985

[Bilateral-velour blood vessel prostheses produced by the Center for Research and Development of the Textile Industry (TRICOMED) in Lódź. Personal experiences].

Two-year observations on 17 patients after the implantation of bilaterally velour vascular prostheses were made. In the postoperative course 5 prostheses underwent occlusion. Special attention was given to the behaviour of the prostheses above and below the knee-joint. The velour vascular prostheses made by the Research Centre Tricomed in Lódź could be a good alternative to other grafts in the surgical treatment of occlusion located in the above knee but in occlusions below the knee they can be used only exceptionally.

Aged↗
PubMed1985

Prosthetic valves or tissue valves--a vote for mechanical prostheses.

Thirty years of effort to obtain better substitutes for destroyed human heart valves brought continuous improvement of the various designs and materials used for the prostheses. However, none of the mechanical or tissue valves currently available meet all the requirements of an ideal artificial heart valve. Accurate comparison of results after implantation of mechanical and tissue valves is difficult because there are no randomized studies and most of the published results are gathered from patient groups operated on in different centers and over different time frames. Reliable comparison therefore presumes criteria to assess the success of valve replacement. The late outcome of heart valve replacement can be determined by subjective improvement, improvement of functional capacity and central hemodynamics, normalization of impaired ventricular function and by the frequency of complications related to or induced by the prostheses. Subjective improvement and improvement of functional capacity is obviously dependent on the degree of postoperative normalization of the hemodynamics. The hemodynamic properties of modern mechanical prostheses are superior to those of tissue valves because of the significantly more favourable relation between total prosthetic valve area and effective prosthetic valve orifice area, conditioned by design. These unfavourable hemodynamics are manifest especially when prostheses of smaller sizes are implanted. The main disadvantage of biological valves is their limited durability due to calcification with tissue damage resulting in degeneration and dysfunction. In addition to the risk of re-operation of tissue valves, for some patients hemodynamical deterioration with consecutive decrease of their functional capacity must be expected a considerable time before a second operation is mandatory. When compared with tissue valves, the most important disadvantage of mechanical valves is their thrombogenicity with the need for life-long anticoagulation therapy. However, the majority of patients with tissue valves do also require long-term anticoagulation because of factors allied by itself with an increased risk of thromboembolism. According to these advantages and disadvantages of mechanical and tissue valves, a differential therapy and an individualized approach should be preferred. Mechanical valves seem to be favourable in young patients, in patients with atrial fibrillation, high risk of reoperation or those in whom only small sized valves can be implanted.

Adult↗
PubMedDate not supplied

Failure of dacron arterial prostheses caused by structural defects.

We have observed unusual aneurysmal complications associated with structural defects of Dacron fabrics in three patients. The first patient had beadshape aneurysms along the course of the bilateral axillo-femoral prosthetic bypasses 4 or 5 years after surgery. Round defects or longitudinal rents in the lower third of the prostheses (Vascular-D knitted Dacron graft of high porosity, USCI) were the source of the aneurysmal complications. In the second patient, the transverse diameter of the aorto-femoral Dacron graft (Vascular-D, USCI) was increased to twice that of the original graft with formation of an anastomotic false aneurysm in the groin 3 1/2 years after surgery. The defective prostheses in these two cases were successfully replaced by Cooley double velour knitted Dacron grafts. The third patient developed an arterio-ureteral fistula originating from a round defect of the aorto-femoral prosthesis (Tetoron that is woven Dacron graft with a low porosity, Nakao-Filter, Japan) 8 years postoperatively and died from massive hematuria and subsequent disseminated intravascular coagulopathy. Microscopic examination of the removed prostheses revealed a complete loss of the conformation of the weave with fragmentation and disruption of the graft fibers. Therefore, patients with Dacron arterial prostheses should be followed up regularly and with great care.

Adult↗
PubMedDate not supplied

[On preclotting of woven Dacron vascular prostheses (author's transl)].

The role and the clinical value of common protocols of preclotting for a woven Dacron vascular prosthesis have been investigated. A comparative study of blood loss was carried out for Standard Woven De Bakey protheses inserted in a specially constructed extracorporeal blood circuit with canine models. The system detected transport of blood across the wall of the prostheses. These measurements were supplemented by gravimetric assessment of blood clot density and scanning electronmicroscopy examination of the internal surfaces of the prostheses. The pre-operative protocols investigated included : absence of pre-treatment, precoagulation with anticoagulant-free blood and various techniques using heparinized blood subsequent to an initial blood contact (modified method of Sauvage). The effect of using heparinized animals was also investigated. Leakages in unclotted prostheses could be reduced almost five fold by any precoagulation technique. Heparinization did not cause a significant increase in leakage and considerably improved the quality of the newly deposited blood product lining on the prostheses which consisted almost entirely of fibrin and eliminated any embolization.

Animals↗
PubMedDate not supplied

[Unicompartmental femorotibial arthroplasty and lateral gonarthrosis. Outcome of 52 prostheses implanted for more than 5 years].

The results of 52 Lotus unicompartmental knee implants with a follow up time exceeding 5 years are analysed. Forty-one prostheses with a mean follow-up of 6.5 years have given very good or good relief of pain. In almost all cases, flexion range exceeds 90 degrees and the preoperative motion has been most often clearly improved. Except for those due to prosthesis infection, all the poor and fair results in terms of pain, are explained by mechanical causes i.e. persistence of a frontal instability, loosening of the tibial component (2 cases) or narrowing of the nonprosthetic femorotibial space (11 cases). The latter is not related to the presence of any radiological chondrocalcinosis. These poor anatomical and clinical results appear to be preventable by a correct operative technique. In particular, the complete correction, by the prosthesis, or the angular deformity which has caused the lateral knee OA must be avoided. This is in contrast to what must be done in osteotomies. Unicompartmental prostheses thus have to stay in stress so that their long term future is uncertain. In the surgical management of lateral knee OA, these prostheses are not to be preferred to correction of frontal angular deformity by osteotomy, except in the elderly, when deformity cannot be completely corrected. Unicompartmental prostheses are particularly indicated in unstable knees in which osteotomies are known to be difficult to perform correctly.

Aged↗
PubMed1978

The influence of design on the transmission of torque across knee prostheses.

Knee prostheses of eight different designs were tested experimentally to determine the axial torque necessary to rotate the tibial component relative to the femoral component with the prosthesis positioned at or near full extension. The results represent transmitted torque as a function of axial rotation. For six designs, the transmitted torque was 11.3 newton-meters (100 inch-pounds) or greater at 6 degrees of rotation, with an axial load of 1556.8 newtons (350 pounds). These prostheses either had close conformation between femoral and tibial components, or were mechanically linked. In these prostheses, the geometry of the articulating surfaces was the primary determinant of torque. For the other two types, under similar loading conditions the transmitted torques were 2.5 newton-meters (twenty-two inch-pounds) at 6 degrees of rotation. These prostheses were designed to allow greater freedom for rotation, and hence for them the primary determinant of torque was friction between the articulating surfaces. The predictive value of this torque characteristic relative to the incidence of loosening will have to be determined by comparison with clinical experience.

Biomechanical Phenomena↗
PubMed1983

Longterm results of 38 knee prostheses.

The authors report the results obtained with 38 knee prostheses reviewed from one to 9 years after insertion and discuss the advantages and limitations of this operation relative to different types of prosthesis. Although this operation has passed the "experimental" stage it has not yet reached a stage of reliability comparable with that of hip prostheses. The sliding prostheses yielded a higher percentage of positive results (81%) than the hinged prostheses (70.5%); the latter, however, are still indicated in selected cases. Knee replacement operations are justified, however, when the only valid alternative is arthrodesis.

Adult↗
PubMed1981

[Late thromboses on tricuspid valve prostheses. Apropos of 6 cases].

Six out of 24 patients with tricuspid valve prostheses, operated between 1968 and 1978, followed-up from 1 to 10 years (average 4,2 years) developed thrombosis. This complication occurred between 15 and 59 months after operation (average 37 months). All patients were female with ages ranging from 18 to 44 years (average 38 years). Starr-Edwards prostheses were used in all cases. Five of these patients were on anticoagulants therapy, which was well within therapeutic limits in 3 patients. In contrast to thrombosis of mitral or aortic valve prostheses, the presenting symptoms were slowly progressive and discreet in 4 patients; in 1 case, the thrombosis was diagnosed on routine follow-up examination. The slow clinical presentation allows time for useful complementary investigations, catheterisation and angiocardiography being the most reliable methods of confirming this difficult diagnosis: these investigations were carried out in 2 patients, and in both cases, very high right atrial pressure with diastolic gradients between the right atrium and right ventricle of over 10 mm Hg were recorded. Cineangiography showed tricuspid regurgitation in both cases with reflux in the vena cavae and very dilated right atria, stagnation of contrast and poor right ventricular filling. Five patients were reoperated with two postoperative deaths. Particular anatomical appearances were observed at operation or autopsy with fibrin and platelet deposits at different levels of the prosthesis (sewing ring and/or struts) interfering and even blocking the function of the ball or disc. Organized thrombus on the cage was only observed in one patient. In this case, the struts on the prosthesis were set in the right ventricular cavity. Thrombosis of tricuspid valve prostheses is generally a slowly progressive complication and may be diagnosed in time by regular follow-up, so that reoperation may be considered without unnecessary delay.

Adolescent↗
PubMed1983

Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prostheses and quantitation of visceral microembolism in dogs.

A noninvasive technique has been developed in the dog model for imaging, with a gamma camera, the platelet deposition on Björk-Shiley mitral valve prostheses early postoperatively. At 25 hours after implantation of the prosthesis and 24 hours after intravenous administration of 400 to 500 microCi of platelets labeled with indium-111, the platelet deposition in the sewing ring and perivalvular cardiac tissue can be clearly delineated in a scintiphotograph. An in vitro technique was also developed for quantitation of visceral microemboli in brain, lungs, kidneys, and other tissues. Biodistribution of the labeled platelets was quantitated, and the tissue/blood radioactivity ratio was determined in 22 dogs in four groups: unoperated normal dogs, sham-operated dogs, prosthesis-implanted dogs, and prosthesis-implanted dogs treated with dipyridamole before and aspirin and dipyridamole immediately after operation. Fifteen to 20% of total platelets were consumed as a consequence of the surgical procedure. On quantitation, we found that platelet deposition on the components of the prostheses was significantly reduced in prosthesis-implanted animals treated with dipyridamole and aspirin when compared with prosthesis-implanted, untreated dogs. All prosthesis-implanted animals considered together had a twofold to fourfold increase in tissue/blood radioactivity ratio in comparison with unoperated and sham-operated animals, an indication that the viscera work as filters and trap platelet microemboli that are presumably produced in the region of the mitral valve prostheses. In the dog model, indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of platelet deposition on mechanical mitral valve prostheses, in vitro evaluation of platelet microembolism in viscera, in vitro quantitation of surgical consumption of platelets, and evaluation of platelet-inhibitor drugs.

Animals↗
PubMed1995

[The long-term results of isolated aortic valve replacement with 19 mm prostheses].

Twenty-five patients underwent isolated aortic valve replacement with 19 mm valves (8 cases with St. Jude Medical prostheses, 7 cases with Carpentier Edwards Pericardial prostheses and 10 cases with Björk-Shiley prostheses). Postoperative echocardiography revealed data as follows. Peak pressure gradients (mmHg) were 40.4 +/- 14.4 (mean +/- S.D.) in the SJM group, 23.4 +/- 9.8 in the CEP group and 50.5 +/- 16.7 in the BS group. End-diastolic left ventricular dimension in the BS group and interventricular septum thickness in the CEP group was reduced significantly. All but one case were in NYHA functional class I or II, and clinical improvement was almost satisfactory in all groups. However, in the BS group, 4 cases showed peak pressure gradients more than 50 mmHg. We conclude that 19 mm aortic prostheses in this study can provide satisfactory results. However, as for mechanical valve, it may be undesirable to choose BS prosthesis.

Adult↗
PubMed1994

A new, automated and accurate in vitro method to quantify endothelial cells attached to vascular prostheses.

Over a decade ago the idea of endothelial cell seeding was introduced in an attempt to improve the function of small caliber vascular prostheses. Although endothelial cell seeding is currently being applied clinically, several questions regarding the functional properties of the seeded endothelial cells remain. Evaluation of functional properties of endothelial cells on various types of vascular prostheses can be performed partly in vitro, but it is hampered by the fact that commonly used methods to quantify endothelial cells do not adequately apply to these cells on prosthetic materials. An accurate quantification method is described that is rapidly and easily applicable to endothelial cells attached to vascular prostheses. The method can also be used to quantify endothelial cells attached to culture dishes or microcarriers. Colorless, non-fluorescing, fluorescein-diacetate was used, which was taken up by the attached endothelial cells, and which was then intracellularly converted to yellow fluorescein, emitting green fluorescence. Subsequently, triton-X-100 was applicated to release fluorescein and levels of fluorescence were measured with the automated aperture-defined microvolume (ADM) method, using an inverted fluorescence microscope to which a photometer was connected. The measured level of fluorescence is linearly related to endothelial cell numbers attached to prostheses. The accuracy and the reproducibility of cell countings are high.

Automation↗