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At least 829 records · Page 46Linked to original sources
PubMed1989

[Experimental studies of the esophageal prosthesis with a polyvinyl alcohol hydrogel].

Though various prosthetic materials have been experimented with for use as an artificial esophagus in the past, the two main problems that have prevented successful clinical implantation of such a prosthesis were anastomotic leakage and stricture formation of the artificial esophagus. The purpose of this study is to evaluate a high water content polyvinyl alcohol hydrogel (PVA-H) for use as the esophageal prosthesis. In 10 adult mongrel dogs, the defect after resection of the intrathoracic esophagus was bridged with a PVA-H esophageal prosthesis, 5.5 cm in length and 15 mm in internal diameter with two Tefron rings, installed 2 cm from each end. The esophageal prostheses, including the anastomotic lines, were enveloped by Dacron mesh after implantation. After implantation, the prostheses were examined endoscopically and fluoroscopically. The dogs, which were sacrificed or had died, were evaluated macro- and microscopically. Among the six dogs underwent operation, one is still living 900 days after implantation. The other two dogs were sacrificed on 165 and 162 days after implantation. The remaining three dogs died of postoperative complications ranging from 25 to 81 days after implantation. The causes of death were the respiratory insufficiency after endoscopical examination, abscess formation around the prosthesis and pyothorax. Up to 2 months after implantation the esophageal prostheses were fixed to the host esophagus without stenosis. However, the prostheses were gradually dislodged due to constricture depending on the growing granulation at the proximal anastomosis. When the surviving dog was examined on the 376th day after the operation, the esophageal prosthesis fell off entirely.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[A clinical evaluation of AMS 700 penile prosthesis in the treatment of impotence].

The AMS 700TM & 700 CXTM penile prosthesis was implanted in 34 organic and mixed-type impotent patients between November, 1984 and July, 1988. The patients' ages ranged between 32 and 70, with an average age of 57.2. Twelve weeks after implantation, the prosthesis was evaluated in terms of patient satisfaction with sexual intercourse and postoperative complications. Twenty three patients (67.7%) were highly satisfied, 7 (20.3%) satisfied, 3 (8.8%) dissatisfied and 1 patient worsened (2.9%). Severe complication was found in two cases, both of them being complicated by infection; as a result the prosthesis was removed. Utility of the prosthesis, e.g. effectiveness and safety was; high utility in 26 cases (76.5%), moderate utility in 7 cases (20.6%), and no favorable in one case (2.9%). Thus, overall effectiveness and safety of the AMS 700 penile prosthesis, with its excellent cosmetic appearance upon implantation, were demonstrated by the above findings.

Adult↗
PubMed1985

Endoscopic removal of an intragastric Angelchik antireflux prosthesis.

Four months after insertion of an Angelchik esophageal antireflux prosthesis, a 60-year-old man was seen with epigastric pain and vomiting. Upper gastrointestinal studies demonstrated intragastric migration of the prosthesis. The prosthesis was intact and the straps were untied , and gastroscopic removal was accomplished by pulling out the prosthesis. Surgeons using this prosthesis should be aware of this unique potential complication of erosion into a viscus.

Endoscopy↗
PubMed1979

[The use of a chondro-metallic prosthesis when the ossicular chain is destroyed (author's transl)].

The author describes a new prosthesis used in functional rehabilitation when the chain is destroyed. It consists of a tripod part in gold, anchored in the attic region with its foot resting on the plate of the stapes. This prosthesis is covered with a piece of autologous cartilage freshly removed from the tragus which forms the junction with the tympanic membrane or covering fascia. 60 cases are presented, some with a follow-up of 4 years. All of the patients were suffering from the sequelae of chronic otorrhoea, with varying degress of destruction of the chain and tympanic membrane, leaving a mobile plate. Functional rehabilitation in one stage was good in 66% of cases, poor in more than 8% of cases and nil in 25% of cases. Tolerance of the prosthesis was comparable to that of other metallic or plastic materials used in the middle ear. The plate of the stapes would appear to tolerate the prosthesis perfectly since no secondary labyrinthisation was seen. The author suggests the use of this chondro-metallic prosthesis was a reliable means of ensuring functional rehabilitation in the presence of a post-otitic empty middle ear.

Cartilage↗
PubMed1983

[Use of the Montgomery prosthesis in the treatment and prevention of anterior commissural synechiae secondary to bilateral cordectomy].

The authors report the results obtained with the use of the Montgomery silicone prosthesis for the prevention or treatment of thick and sometimes partially stenosing synechiae of the anterior commissure following bilateral cordectomy by median thyrotomy. The umbrella-shaped prosthesis consists of two silicone sheets which are perpendicular to each other. The vertical sheet is of variable length and, once placed in position, it separates at the anterior commissure the two portions of larynx operated on, so that they may be adequately reepithelized. This procedure was used in three patients undergoing internal subperichondral cordectomy by median thyrotomy, due to a malignancy in both vocal folds which, however, was not extended to the anterior commissure. In two patients the prosthesis was fitted in during the main surgical procedure to prevent an excess of scar tissue; in the third patient, by contrast, it was used to treat a thick, partially stenosing synechia in the commissure secondary to cordectomy, which had already been unsuccessfully managed under direct microlaryngoscopy. In the three patients the prostheses were left in place for 2 and a half, 3, and 3 and a half months, respectively, with no major irritation or inflammation inside the larynx. No supportive tracheotomy had to be performed, and only in one case was the prosthesis secured externally by percutaneous stitching. On indirect laryngoscopy several months after the prosthesis was removed, two patients showed a perfectly healed larynx; in the third patient a very small amount of scar tissue in excess was still present, but it did not affect his respiratory function.

Adult↗
PubMedDate not supplied

Reconstruction of the trachea and stem bronchi with Neville prosthesis.

Fifty-four patients with tracheal stenosis due to benign stricture and malignancy underwent airway reconstruction with a molded Silicone prosthesis (Neville Prosthesis). In 40 patients, the trachea was reconstructed with a straight prosthesis; of these 29 had a postintubation stricture and 11 a malignancy. In the former group, there was one early death from erosion of the innominate artery and five late deaths from a variety of causes. The postoperative complications were related to granulomas at the anastomotic site in four patients and were due to the use of non-absorbable suture material. Subglottic granulomas occurred in two patients and were successfully treated with fulguration. The lesion was resected and the trachea reconstructed with the prosthesis in eight individuals, five of whom are alive, one to six years postoperatively. Of the three patients, in whom the prosthesis served as an intraluminal stent, one who received irradiation is alive three years after operation. In 14 patients, in whom a carinal resection was performed for malignancy, five individuals are alive, from one to eleven years after surgery. There were four suture line granulomas in the entire group. All of the deaths were attributable to residual or disseminated cancer.

Bronchi↗
PubMed1994

[Tendon interposition arthroplasty vs Kessler silicone prosthesis for basal joint arthritis of the thumb].

Of 86 patients with osteoarthrosis of the trapeziometacarpal or pantrapezial joint operated on during 1978-1988, 52 cases (14 males, 38 females) were reviewed. 32 had undergone interposition of the flexor carpi radialis tendon and 18 Kessler's silicone prosthesis technique. 2 had silicone prosthesis replacement in 1 hand and tendon interposition in the other. The average age of all patients was 65.5 years (range 56-74). Average follow-up was 7.0 years for the 32 after the interposition procedure (range 8-14), and 10.5 years (range 8-14) after prosthesis implantation. A greater proportion of those after tendon interposition reported alleviation of pain. There was no statistically significant difference between the groups with regard to patient satisfaction, need for job change, range of abduction and opposition, grip and pinch power, thumb length and ability in activities of daily living. Tendon interposition arthroplasty is simple and relatively inexpensive compared to silicone prosthesis insertion, which has inherent complications, such as breakage of the prosthesis and synovitis. Tendon interposition has therefore been our standard procedure since 1988.

Aged↗
PubMed1994

[Replacement of the trachea with a prosthesis--an unsolvable problem?].

Reconstruction of the trachea by means of a segmental prosthesis is a complicated problem, which has not been completely resolved so far. The authors present a brief historical review of attempts to bridge the gap by different types of prostheses Evon Neville's silicone prostheses are not well tolerated on a long-term basis and its is thus important to look for other materials for the manufacture of an "ideal" tracheal prosthesis. (ur synthetic prosthesis made from poly/ARMA/is very well tolerated, similarly as silicone prostheses. Despite this the authors produced in 1993 a new type of prosthesis, based on antigenicity-deprived heterologous pig tissue. Trials with this prosthesis will be evaluated in a subsequent paper.

Humans↗
PubMed1996

Comparison of a new type of polytetrafluoroethylene patch (Mycro Mesh) and polypropylene prosthesis (Marlex) for repair of abdominal wall defects.

BACKGROUND: Two types of prosthetic material used for repairing hernial defects of the abdominal wall were compared: Mycro Mesh and Marlex. Mycro Mesh (MM) is a new polytetrafluoroethylene product of layered, microporous structure. Macroscopically, it presents regularly distributed, 2-mm orifices that perforate the biomaterial. Marlex (PL) is a well-known polypropylene mesh product with a macroporous structure. STUDY DESIGN: In 24 white New Zealand rabbits, a full-thickness (except skin) 5 x 7-cm defect was created in the anterior wall of the abdomen. Defects were repaired with either MM (n = 12) or PL (n = 12) implants and studied at 14, 30, 60, and 90 days after implantation. Samples of the interfaces between prosthesis and subcutaneous tissue, visceral peritoneum, and receptor tissue, respectively, were studied. Samples were processed for optical microscopy and scanning electron microscopy (SEM). An immunohistochemical study was made using RAM-11, a monoclonal antibody specific for rabbit macrophages. The tensile strength of the repairs was made using an Instron tensiometer on 2-cm wide transversal strips that included the prosthesis and its anchor zones to the receptor tissue. RESULTS: The formation of adhesions between the prosthesis and intestine was important with the PL implants but not with the MM implants. Optical microscopy and SEM showed formation of an organized connective tissue surrounding the MM implants. At 90 days, compact bridges of connective tissue linked the tissue on the subcutaneous and peritoneal sides of the prosthesis. The PL implants became integrated into a disorganized, highly vascularized connective tissue. The intensity of the macrophage response was similar in both prostheses and decreased between days 14 and 90 (Student-Newman-Keuls test p = 0.01). The tensile strength of the PL implants was greater than that of the MM implants. At 90 days, the tensile strength of the PL implants was mean equals 33.11 N and of the MM implants, mean equals 22.65 N (Mann-Whitney test p < 0.001). CONCLUSIONS: The tissue integration of the PL and MM implants differed; fewer visceral adhesions formed on MM than on PL; the macrophage reaction was not determinant of the success of failure of either biomaterial; and the tensile strength of the prosthesis-receptor tissue interface was much greater in the PL implants than in the MM implants.

Abdominal Muscles↗
PubMed1986

Prolonged survival with a thrombotically occluded tricuspid valve prosthesis.

A 49-year-old man who had undergone tricuspid valve replacement with a Björk-Shiley prosthesis in November 1974 was reoperated on in January 1985 due to prosthesis malfunction. The operation revealed a totally occluded prosthetic valve and a paravalvular defect which had served as the channel for atrioventricular blood flow. In retrospect, all evidence indicated that the valve had stuck as early as six months after the primary operation, when the patient had first noticed the loss of audible valve clicks and the reappearance of effort intolerance. Due to the gradual progression of the patient's symptoms and misinterpretation of the significance of absent valve clicks, the correct diagnosis was not made until a follow-up study 10 years after the first operation when contrast echocardiography showed the absence of both disc movements and transvalvular contrast flow. Our experience indicates that thrombosis of a tricuspid valve prosthesis may present highly insidiously and that the loss of audible valve clicks should be relied on as a sign of prosthesis malfunction.

Adult↗
PubMed1995

[Replacement of infected total hip prosthesis in two stages].

Since 1975 we have treated 36 infected hip replacements by a two stage procedure in which the prosthesis and cement were first removed. Gentamicin impregnated beads were left at the sites of the prosthesis. Not less than 45 days later a fresh prosthesis was inserted into the hip. In two hips revision was not undertaken because of persistence of infection. The remaining 34 hips received a fresh prosthesis when the site was bacteriologically sterile. Gentamicin impregnated cement was used and antibiotics were given for a further three months. The functional results were satisfactory at an average of five years of follow up. Incomplete removal of methylmethacrylate was a factor in the persistence of infection and of pain in the absence of infection. The bacteriological efficacy of Gentamicin impregnated beads is uncertain, but their use gave a better functional result.

Anti-Bacterial Agents↗
PubMed1987

The importance of trochanteric lag screws to achieve primary stability in cementless fixation of the RM hip prosthesis.

To allow the bony incorporation of a cementless prosthesis it is important to achieve stability at the time of operation. To neutralize tension and torsional stresses the RM-shaft prosthesis is fixed with two lag screws in the trochanteric part of the femur. By measuring the applied torque intraoperatively we could demonstrate that the threads of the screws found a better grip when inserted from the bone to the prosthesis. Thus, the stronger fixation of the screws enhanced the primary stability of the cementless prosthesis.

Bone Cements↗
PubMed1992

[Experiences with the isoelastic prosthesis in treatment of humerus metastases].

39 patients with pathological fractures of the humerus were treated by isoelastic polyacetal endoprosthesis. Ten patients received a humeral-head-prosthesis and 32 a prosthesis of the humeral-shaft. The average survival time was nine months. Three times within the first group of twelve patients fracture of the cone of the prosthesis occurred. Therefore an additional stabilization of the contact zone between bone and prosthesis by plate-osteosynthesis was performed in the following 20 operations, preventing breakage of the material. In contrast to the conventional posterior approach to the humeral-shaft we chose a ventrolateral approach between the biceps and triceps muscle. This technique is less traumatic and leads to a shorter operation time. In patients with pathological humeral fractures a conception of treatment is demonstrated which provides an immediate stability by using endoprostheses to preserve the quality of life of oncological patients.

Bone Neoplasms↗
PubMed2003

Mitral valve replacement for children with a small annulus using ATS open pivot prosthesis.

OBJECTIVES: The present study was conducted to review our experience of mitral valve replacement (MVR) in small children with the ATS open pivot prosthesis. METHODS: Between January 1999 and March 2002, 14 patients (7 males and 7 females) underwent a total of 15 ATS MVRs; 16AP in 9, 18AP in 3, and 20AP in 3 occasions. The mean age and body weight at operation were 1.1 +/- 0.7 (range 0.2 to 2.7) years and 6.8 +/- 2.6 (range 2.8 to 12.5) kg, respectively. RESULTS: There were 2 early and 2 late deaths, each non-valve related. Excluding one patient, the orifice size of the prosthesis was larger than the predicted normal size of the mitral valve for the age. The postoperative Doppler echocardiogram demonstrated normal maximal flow velocity across the prosthesis. There was no morbidity among survivors except for the patient who developed a stuck and immobile valve disc 10.2 months after the operation and required re-replacement. CONCLUSIONS: Our experience shows that MVR with the ATS open pivot prosthesis is a promising surgical option for small children.

Child, Preschool↗
PubMed2003

[Total elbow arthroplasty. Indications, operative technique and results after implantation of an Acclaim elbow prosthesis].

Total elbow arthroplasty has become a reliable treatment option for patients with rheumatoid arthritis as well as primary or posttraumatic arthrosis. The aim of this study is to present the indications, operative technique and results for the implantation of an Acclaim elbow prosthesis. Case reports are given to demonstrate the indications for prosthesis implantation. Furthermore, the follow-up results are reported for 65 patients after implantation of an Acclaim prosthesis. Pre- and postoperative pain were evaluated using the visual analogue scale. The pain level decreased from 8.0 to 2.3 postoperatively. After implantation of an elbow prosthesis, there was a significant improvement in the range of motion. The mean flexion increased from 103 degrees preoperatively to 140 degrees postoperatively. An increase of 10 degrees was found for both supination and pronation. Complications included temporary ulnary nerve irritation in seven patients, intraoperative fractures in four cases and postoperative elbow dislocation in one case. In conclusion, total elbow arthroplasty results in a reduction of pain and an improvement in elbow movement. However, selection of the right patient is important. Patients are advised not to lift heavy objects or to perform hard physical work. If patients' compliance can not be ensured preoperatively, no total elbow arthroplasty should be performed.

Aged↗
PubMed2003

Differential gene expression in the periprosthetic membrane: lubricin as a new possible pathogenetic factor in prosthesis loosening.

About 10% of hip endoprostheses will loosen after 10 years. Prosthesis loosening is caused by two different pathomechanisms: aseptic loosening (AL) and septic loosening (SL). This study evaluated differences in gene expression in AL and SL. Eight hybridizations were performed on PIQOR cDNA arrays. Objects of the study were periprosthetic interface tissue samples from two patients with SL and three patients with AL. Tissue parts directly adjacent to the site of RNA isolation were analyzed immuno/histopathologically in order to overcome the problem of tissue heterogeneity. Thirty-three genes were found constantly differentially expressed, among which were cd11b, cd18, cd68, osteopontin and ferritin heavy-chain upregulated in AL and collagen types 1alpha-1, 3alpha-1, integrin alpha-1, thrombospondin2 and nidogen upregulated in SL. The most striking finding was the strong upregulation (from 20-fold to 323-fold) of megakaryocyte stimulating factor (msf) in all aseptic cases and one of the two septic cases, which was confirmed by real-time reverse transcription-polymerase chain reaction. In this study, msf is linked to prosthesis loosening for the first time. The upregulation in AL suggests an important pathogenetic role: the msf splice product lubricin is responsible for the lubrication of healthy joints, but its excellent lubrication ability may disturb the tight interaction between bone and prosthesis and thereby contribute to prosthesis loosening.

Aged↗
PubMed2000

Value of bone scintiscan for diagnosis of arterial prosthesis infection: preliminary results.

Diagnosis of arterial prosthetic infection is often difficult to confirm. Several cases of lower extremity hypertrophic osteoarthropathy (HOA) have been associated with arterial prosthetic infection. The presence of bone and joint abnormalities could constitute an early sign of HOA. The purpose of this prospective study was to determine the diagnostic value of routine bone scintiscan in patients hospitalized for suspected arterial prosthesis infection. Between December 1995 and May 1997, 17 patients with suspected infection were admitted to our institution. All underwent bone scintiscan before surgical treatment. Presence or absence of infection was defined according to the criteria proposed by Yeager. During the same period, bone scintiscan was performed in a control group of 8 patients with arterial prostheses but no clinical or laboratory signs of infection. Scintiscans were studied to detect bone and joint abnormalities distal to the arterial prosthesis. The results of this preliminary study indicate that routine bone scintiscan can assist definitive diagnosis in patients with suspected arterial prosthesis infection. Demonstration of bone and joint abnormalities distal to a prosthesis appears to be a fairly sensitive and highly specific sign of infection.

Aged↗
PubMed1995

Fixation and effect on bone strain pattern of a stemless hip prosthesis.

Given the relatively short survival time of total hip replacement in young patients, a different concept of femoral implant was designed and evaluated biomechanically prior to clinical application. The femoral component has no intramedullary stem and fits into an angular resection of the femoral neck. A trans-trochanteric screw provides immediate strong fixation. A comparative biomechanical study with cadaver femora and a dynamic hip simulator was performed. The study had three objectives. (1) The strains generated under loading in the intact proximal femur were compared to those generated in the presence of the experimental implant and a classic cemented implant. (2) The short-term stability of the experimental prosthesis under loading conditions encountered during fast walking was evaluated. (3) Most importantly, the implant design was improved in the light of the experimental observations prior to any clinical trial. Indeed, the prototype underwent several important modifications in the course of the study. With the modified design, later used in a clinical trial, it was demonstrated that if accurate fit and position of the prosthesis were provided, fixation remained sound for over one million loading cycles with peak loads of three times the body weight. The measured interface micromotion was compatible with direct bone apposition and ingrowth. No statistical difference was found between the strain measurements obtained before and after implantation of the experimental prosthesis whereas significant stress shielding was observed with a stemmed, cemented prosthesis.

Biomechanical Phenomena↗