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PubMed1981

The TC double socket above-knee prosthesis.

The conventional total contact suction AK prosthesis presents several disadvantages, such as difficulty in wearing the socket in a sitting position, difficulty in obtaining a favourable disposition of the stump soft tissues in the socket and difficulty in avoiding stump perspiration problems. In an attempt to solve these disadvantages, a new AK prosthesis with a thermoplastic double socket was developed at the Tokyo Metropolitan Rehabilitation Center for the Physically and Mentally Handicapped. The double socket is composed of an external socket attached to the lower parts and a detachable internal socket, and appears to solve all the disadvantages of the conventional prosthesis. This prosthesis is called the TC prosthesis, and abbreviation for the Tokyo Metropolitan Rehabilitation Center. The first model of this prosthesis, (TC-1) has a metal valve. A new rubber sheet valve was developed to solve several disadvantages of the metal valve in the TC-2 prosthesis. Since November 1978 the TC-1 has been fitted to 295 AK amputees, including 9 bilateral AK amputees, and since March 1980, 145 AK amputees have received the TC-2, including 6 bilateral amputees. Satisfactory results have been obtained with both prostheses.

Amputation Stumps↗
PubMed1985

Hanging stump prosthesis without socket for bad above-knee stumps.

This prosthesis was developed in the Department of Rehabilitation, Safdarjang Hospital, New Delhi, India to deal with the problems of badly formed or difficult above-knee stumps. Bad stumps are still a challenge for the rehabilitation team due to the difficulty in fitting the prosthesis which is the first stage in the total rehabilitation of the amputee. It is the author's observation that those cases with bad above-knee stumps who are fitted with a prosthesis with some type of socket keep attending the prosthetic section complaining of pain. The pain in most of these cases is due to local contact of the stump surface with the socket. None of the prostheses already available can deal with this problem effectively. The hanging stump prosthesis without socket has been developed on the principle of no socket, no contact, no pain. This prosthesis has no socket but a metallic ring consisting of a well padded, well moulded ischial seat. This metallic ring is attached to the hollowed out wooden thigh piece by medial and lateral vertical bars. The outer side of the metallic ring is attached to the pelvic belt through the hip joint. The rest of the prosthesis is similar to the standard above-knee prosthesis.

Amputation Stumps↗
PubMed1997

The effects of prosthesis mass on metabolic cost of ambulation in non-vascular trans-tibial amputees.

The effect of prosthesis mass on the metabolic cost of steady-state walking was studied in ten male non-vascular trans-tibial amputees (TTAs) and ten non-amputee controls. The subjects underwent four trials of treadmill ambulation, with each trial performed for nine minutes at level grade and 76 m/min. Twenty minutes of seated rest followed each trial. During trials numbers one and two, TTAs ambulated without mass added to their prosthesis. During the third and fourth trials, either 454 or 907 grammes mass (1 or 2lbs mass respectively) were randomly assigned and added to either the prosthesis or the leg of the non-amputee control. Subjects were blinded to the amount of mass added to their limb. Within-group comparisons across the four trials showed significant differences in oxygen consumption (VO2) and heart rate (HR) between the two non "mass added" trials, but no effect for addition of mass. The VO2 of TTAs was only 0.6 ml/kg/min (4.7 percent) greater during walking following the addition of 907 grammes to the prosthesis than without mass addition at all, while HR averaged only 1.4 beats/min. higher under the same testing condition. Pearson-product moment correlations echoed these findings, as moderate, but in all cases, negative correlations were observed for associations among the factors of subject age, stump length, and prosthesis-shoe weight, and both VO2 and HR. It was concluded that adding up to 907 grammes mass to a non-vascular TTA's prosthesis will not significantly increase the energy expenditure or HR at a normal walking speed, and that elevated energy cost of ambulation in repeated measures testing without mass added may reflect task familiarization and not an added burden of prosthesis mass.

Adult↗
PubMedDate not supplied

[Echocardiographic study of the Björk-Shiley disc prosthesis (author's transl)].

The echocardiography of 25 patients with Björk-Shiley disc prosthesis (16 aortic, 7 mitralic, 1 both mitralic and aortic and 1 both mitralic and tricuspidal) was studied. Mitralic prosthesis were placed with the shortest disc segment looking forward; aortic prosthesis faced the shortest disk segment looking towards the coronaric sinus. The echo's morphology is related to the multiple relationships among position and direction of the prosthesis and the probe. In the aortic echocardiogram, it is possible to recognize echoes from the ring dissociated by anterior and posterior aortic walls. Between them echoes corresponding to the open disc appear, making a quadrangular figure. The values of the internal diameter of the ring obtained were very similar to the real value (difference 0-1 mm). Mitralic echocardiogram is characterized by the valvular disc movement tracing the typical quadrangular pattern, which is due to its opening and closure. Echoes of the supporting apparatus can be recorded directing the probe toward the heart base. In aortic and mitralic prosthesis, disc movements can be estimated. Opening and closure speed rate and their correlation vary on a large scale, both within different patients and in the same patient. Maximum disc excursion appears to be a more homogeneous and constant data in long-term controls and can be used to estimate valvular functionality: in aortic prosthesis valve the obtained value (mean = 17.46 +/- 0.53 "ES") is similar to the real diameter of the disc, in mitral prosthesis valve the value obtained (mean = 17.50 +/- 0.74 "ES") is shorter than the real value.

Adolescent↗
PubMed2002

Hydrodyamical assessment of valve prosthesis made of expanded ultra-microporous Teflon in vitro.

OBJECTIVE: To assess the hydrodynamical performance of the valve prosthesis made of expanded ultra-microporous Teflon in vitro. METHOD: Sheets of the expanded ultra-microporous Teflon were sewn onto flexible bracket to prepare artificial valve prosthesis. The leakage and steady flow of the valve prosthesis was tested in vitro with Baxter valve prosthesis as control. RESULTS: The rate of leakage of this new valve prosthesis was similar to that of Baxter valve prosthesis (P>0.05), and the systolic pressure gradient of the former was much lower than control(P<0.05). CONCLUSION: This new artificial valve prosthesis has good in vitro hydrodynamical properties, which are superior to Baxter valve.

Heart Valve Prosthesis↗
PubMed1976

[A new mitral valve prosthesis (Cooley-Cutter). Experiences on 241 cases of valvular replacement (author's transl)].

A new mitral valve prosthesis (Cooley-Cutter) is described, which incorporated a low profile design, an excentric sewing cuff, a full flow orifice, a controlled regurgitation for self-washing and symmetrical peripheral flow. The new prosthesis has a titanium double-caged frame, a Pyrolite carbon poppet and a Teflon knit sewing cuff. We have attempted to incorporate in the design of this new prosthesis tre most favorable features of each of many types of prosthesis used at the Texas Heart Institute since 1962. Isolated prosthetic mitral valve replacement for severe congenital or acquired valvular disease was performed in 541 patients from June 1971 to ne 1975. Of these, 66 patients received a concomitant aortocoronary bypass and 31 tricuspid annuloplasty. In 72 patients a malfunctioning mitral prosthesis of other types was replaced with the new Cooley-Cutter prosthesis. There were 49 early deaths (9.1%) and 33 late deaths (6.1%). The most gratifying results were a low incidence of late thrombo-embolic phenomena (1.8%) and absence of hemolisis, malfunction, infection and material failure of the prosthesis.

Adolescent↗
PubMedDate not supplied

Experimental study of a new tracheal prosthesis made from collagen-grafted mesh.

The efficiency of a new tracheal prosthesis was studied. The prosthesis consists of fine Marlex mesh reinforced with a continuous Teflon spiral, and it is grafted and coated with pig collagen, with the aim of promoting connective tissue infiltration and providing air-tightness during the initial stage of implantation. Complete surgical resection and replacement of a 4-6 tracheal ring segment of the cervical trachea was performed in 13 adult mongrel dogs. Except for two dogs that developed anastomotic insufficiency, the prostheses in all dogs were infiltrated by the surrounding connective tissue, and were completely incorporated by the host trachea at the anastomotic sites. Formation of respiratory epithelium that lined the prosthesis lumen, was seen to varying degrees, and in one dog killed at 4 months after reconstruction, this was confirmed histologically from the upper to the lower anastomosis of the prosthesis. Stenosis of the lumen often occurred, however, due to deformation of the prosthesis and overgrowth of granulation tissue. The authors conclude that this tracheal prosthesis is highly biocompatible, and might be useful for repairing tracheal defects by improving prosthesis processing, especially that used for insertion of stents.

Animals↗
PubMedDate not supplied

[Our experience on the use of the antireflux prosthesis by the Angelchik method (personal contribution of 26 cases)].

The Angelchik prosthesis was used in 26 cases of gastroesophageal reflux disease resistant to medical therapy. The operations were crowned with success in 24 cases out of 26 (92.3%), with complete disappearance of reflux. The procedure failed in two cases: the prosthesis was removed in one case due to postoperative acute haemorrhagic gastritis with a subsequent positive outcome; in this patient the Angelchik ring had been removed as a precaution. Failure in the second case, a patient with oesophageal stenosis and a short oesophagus, was due to mediastinal migration of the prosthesis. In this latter case, a successful duodenal bypass was created with antrectomy and a long Roux-en-Y anastomosis. The only intraoperative complication in the patient sample was a splenectomy for rupture of the splenic capsule. Postoperative complications not directly related to the prosthesis were perforation of a duodenal ulcer not diagnosed preoperatively and treated with raphia without impairing the functional efficacy of the ring, one case of pulmonary embolism and one case of cardiac infarction, all resolved with medical therapy. In all, the prostheses were removed in 3 cases out of 26 (11.5%). In addition to the two cases already described, the prosthesis was removed in one patient one year after the operation at the patient's specific request for "psychological" reasons. Migration of the prosthesis occurred in four cases of severe oesophageal stenosis with a short oesophagus, in three of which the prosthesis functioned perfectly even in the intrathoracic site. At follow-up examinations there was radiological disappearance of the hiatal hernia in 20 cases out of 25. In one case there was no hernia even before the operation, and in four cases there was a short oesophagus with severe oesophagitis. Owing to the very easy performance of the operation together with its unquestionable antireflux efficacy, in our opinion three reliable indications emerge, namely: (i) in elderly patients at high surgical risk; (ii) in obese, brachytypical patients; and (iii) in the presence of severe oesophagitis, even with a short oesophagus.

Evaluation Studies as Topic↗
PubMed1986

Complications of the Angelchik prosthesis in the management of gastroesophageal reflux.

There have been a number of reports on the complications of the Angelchik silicone prosthesis since Angelchik and Cohen first reported the use of the device in 46 patients with gastroesophageal reflux. The exact incidence of complications is difficult to estimate; however, the company estimates 0.81 per cent for migration and 0.15 per cent for erosion of the prosthesis. The purpose of this paper is to review our experience with 13 complications related to the Angelchik prosthesis in eight patients referred to Emory University Hospital. These complications consisted of recurrent reflux esophagitis in six patients, intractable dysphagia in two, esophageal stricture in two, displacement of the prosthesis in two, disruption of the prosthesis in one patient, and gastric erosion in two patients. The management of these complications required removal of the prosthesis and performance of a Nissen fundoplication in six patients. Distal esophagectomy with esophagogastrostomy was performed in one patient, and colon interposition was performed in another patient. In summary, serious complications of the Angelchik prosthesis implanted for gastroesophageal reflux and their management are presented.

Adult↗
PubMedDate not supplied

A fibrous polyurethane microvascular prosthesis. Morphological evaluation of the neo-intima.

A fibrous polyurethane microvascular prosthesis with an inner diameter of 1.5 mm was implanted to replace the rat aorta between the left renal artery and the bifurcation of the aorta. Twenty-four implantations, using three different lengths (0.5; 1; 1.5 cm), were carried out. Rats were sacrificed 3, 6, 9 and 12 weeks after implantation. Only 1 prosthesis was occluded (probably due to a technical error). Grafts were already lined with a neo-intima by the third week, irrespective of their length. Different shapes of endothelial cells were recognized. It appeared that cells arise and migrate from the aortic stumps into the prosthesis, since the neo-intima is thicker in the anastomotic area than in the middle of the graft. The well-defined neo-intima consisted of several layers of smooth muscle cells embedded in a glycoprotein matrix and covered by a very flat continuous endothelium. The structure of the prosthesis allowed anchoring of the lining cells. Migration of cells through the wall of the prosthesis was not observed. At those places in the prosthesis where fibres had fused together to form flat areas the neo-intima became torn by the contraction of the myofibroblasts. This was because the cells had evidently failed to become anchored to the prosthetic wall. The neo-intima retained the ability of immediate repair of small defects which develop occasionally on the non-fibrous areas of the luminal surface of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

[Aortic valve replacement with Starr-Edwards and Björk-Shiley prosthesis. Long term results and statistical analysis of some risk factors (author's transl)].

285 patients who underwent aortic valve replacement between 1972 and 1977 have been studied. 197 patients had a Starr-Edwards prosthesis and 88 patients had a Björk-Shiley prosthesis, both groups presented similar risk factors. The follow-up varied between a period of 6 months minimum and 72 months maximum, the mean period is 3.6 years. The statistical results have been realized based on the multi-factor analysis (cluster) which were the basis to define the homogeneous groups of patients with the Starr prosthesis and the Björk prosthesis. One may observe the best survival percentage after 72 months from surgery date in patients with the Björk prosthesis comparing them with those patients who underwent aortic valve replacement with the Starr prosthesis (resp. 93 and 71%). The difference is important from the statistical point of view. The embolic incidence after such a period is nearly equal (16% for Björk and 14% for Starr). The cluster analysis of the considered parameters (age, duration of symptoms before surgery, NYHA class, C/T) did not evince real and proper risk factors such to condition, at long term, the results even if differences in mortality and in embolic incidence, with regards to the relation with NYHA class and symptoms; duration, have been observed. One may conclude that one of most important risks derives form the type of used prosthesis.

Adolescent↗
PubMed1982

[Hemodynamics of the St. Jude Medical aortic prosthesis in comparison to the Björk-Shiley and Lillehei-Kaster prostheses].

Pre- and postoperative hemodynamic data in 10 patients in whom the aortic valve was replaced by a St. Jude Medical (SJM) prosthesis are compared with those in 29 patients who received a Lillehei-Kaster tilting disk (LK) valve prosthesis and 11 patients with a Björk-Shiley tilting disk (BS) valve prosthesis. The SJM aortic prosthesis of the small size (A 21) has advantages over the LK and BS types, and it is therefore particularly suited to use in a small aorta. There are also good hemodynamic results for the larger sizes of the SJM prosthesis. As a result of the 85-degree opening angle and the favorable ratio between the inner and outer diameters of the valve (suture ring), there is only minor impedance of blood flow. The SJM aortic prosthesis thus involves a lesser degree of hemolysis than the BS and the LK. In spite of the promising hemodynamic data, however, long-term findings on the durability of the SJM prosthesis in vivo have not yet been published. It therefore seems to us justifiable, especially where the aorta is large, to continue to use BS prostheses.

Aged↗
PubMed2005

The Oxford unicompartmental knee prosthesis: an independent 10-year survival analysis.

One hundred forty-nine medial prostheses were implanted in 140 patients between 1988 and 1996. After a mean of 67 months 28 patients had died, without the need for revision. Seventeen prostheses were lost to follow-up. Revision surgery using a total knee prosthesis was performed in 16 cases. In four others, a lateral prosthesis was implanted subsequently to a medial one. One of these four was revised to a total knee prosthesis 6 years later. In another four cases, late complications of the meniscal bearing were treated with replacement of this bearing. The surviving prostheses were seen back after a mean of 126 months. The cumulative survival rate at 10 years was 82% for the whole population and 84% when knees with a previous high tibial osteotomy were excluded. Since these results compare poorly to the survival of total knee arthroplasty, this prosthesis is not the first-choice implant. Because it preserves a maximum of bone stock and is revised to a total prosthesis almost without difficulty, it is the first-choice implant for medial unicompartmental osteoarthritis in patients younger than 65. Further research is mandatory to confirm that this prosthesis very rarely needs revision in patients older than 75. It should not be used in osteotomized knees.

Aged↗
PubMed2000

Short- and medium-term results of the thrust plate prosthesis in patients with polyarthritis.

The thrust plate prosthesis is an implant with metaphyseal fixation to the proximal femur, which leaves the diaphyseal bone untouched. Therefore, this implant is preferred in younger patients. It is dependent on good bone quality in the proximal femur. Because the bone quality is reduced in patients with polyarthritis, this kind of endoprosthesis may have a higher failure rate than conventional stemmed endoprostheses in these patients. Therefore, in patients with polyarthritis, even short- and medium-term results of the thrust plate prosthesis should be analyzed. In all, 47 thrust plate prostheses were implanted in 42 patients with polyarthritis (29 with rheumatoid arthritis, 6 with juvenile chronic arthritis, and 7 with spondylarthritis) and followed prospectively. The average age at operation was 40.8+/-10.7 years. Each patient was clinically and radiologically examined preoperatively, 3 and 6 months after the operation, and at the end of each postoperative year. The mean follow-up was 26.1+/-10.7 months. The clinical findings were evaluated using the Harris hip score. Radiologically, 8 different zones of the thrust plate prosthesis were analyzed for radiolucencies. During the 1st year, the Harris hip score rose continuously from the preoperative average of 42.4+/-6.5 points to 78.8+/-10.3 points 3 months postoperatively, 82.3+/-9.8 points 6 months postoperatively, and 86.8+/-10.1 points 1 year after the operation. The subsequent examinations showed Harris hip score remained at the same level. Five patients (5 joints, 10.6%) had to undergo a revision of the thrust plate prosthesis due to aseptic loosening in 3 and septic loosening in 2. Six prostheses (12.6%) showed radiolucencies, mostly below the thrust plate in zones 1 and 2. Two of them were certainly radiologically loose, which raised the failure rate to 7 of 47 (14.8%). The thrust plate prosthesis improves function and alleviates pain in patients with polyarthritis to a satisfactory degree. Concerning the failure rate, this type seems to yield slightly worse results than cementless stemmed endoprostheses in the same patient group. Due to the preservation of the diaphyseal bone of the femur and the possibility of an unproblematic change to a stemmed endoprosthesis, the thrust plate prosthesis can be recommended for younger patients with polyarthritis.

Adult↗
PubMed2003

Experimental study of a porous rat tracheal prosthesis made of T40: long-term survival analysis.

In order to repair large defects in the laryngotracheal area, we developed a biomaterial based on porous titanium (Ti40) formed of spherical particles that are welded together. These Ti40 beads were arranged in several layers to create the rat tracheal prosthesis. After a partial tracheal resection, the prosthesis was fixed to both extremities to replace the missing part. Tissue surrounding the prosthesis was collected from 33 surviving animals after an implantation period of 3 to 12 months. Histological analyses showed that the periphery of the prosthesis was covered with fibroblasts and a few lymphocytes that penetrated the titanium layers. A ciliary cylindrical epithelium of respiratory type was found on the endoluminal side. The inflammatory reaction observed was minimal. These data indicate that the prosthesis, implanted in a laryngotracheal environment, is well tolerated by animals. Our results represent the first step towards the construction of a total laryngeal prosthesis that should allow restoration of the essential functions of the larynx after a laryngectomy in cancer treatment.

Animals↗
PubMed2001

Incidence of tracheo-oesophageal fistulas after primary voice rehabilitation with the Provox or the Eska-Herrmann voice prosthesis.

Salivary leakage can be a major symptom of valve failure or incorrect positioning of indwelling voice rehabilitation valves in a tracheo-oesophageal fistula. Usually, removal of the valve for a short time leads to shrinking of the fistula or a simple valve replacement procedure resolves the problem. If the fistula, however, does not close spontaneously, symptoms persist and the fistula may have to be closed surgically. In a retrospective study, data of 103 patients who underwent laryngectomy and primary voice rehabilitation between 1989 and 1998 with either the Provox or the Eska-Herrmann prosthesis were compared with regard to surgical fistula closure requirement. A total of 55 patients underwent laryngectomy and primary voice rehabilitation with the Eska-Herrmann and 48 with the Provox prosthesis. Initial tumour treatment also included post-operative radiotherapy for all patients in the study. In total, surgical fistula closure had to be performed in three patients, all of whom had been treated with the Provox prosthesis. The time span between initial voice rehabilitation and surgical closure of the fistula was 5 months, 21 months and 24 months in all three patients respectively. None of the fistulas developed in relation to recurring tumour disease. The Provox prosthesis seem to have a higher risk of developing fistulas necessitating surgical intervention, even years after initial tumour therapy, than the Eska-Herrman prosthesis. These complications may be due to the larger tracheo-oesophageal fistula necessary to fit the larger diameter of the Provox prosthesis.

Adult↗
PubMed1994

GFS Mark II inflatable penile prosthesis: four-year clinical study.

OBJECTIVE: The objective of the study was to evaluate the mechanical performance and the patient/partner satisfaction of the GFS Mark II inflatable penile prosthesis (IPP). METHOD: A total of 138 patients had GFS Mark II IPP implants between October 1988 and December 1991 with a follow-up of twelve to fifty months (mean 31.7 months) were studied. Each patient was evaluated for prosthesis performance and each patient/partner satisfaction was evaluated by a questionnaire and personal interview. RESULTS: There was only one prosthetic mechanical problem which involved the tubing. There were seven problems requiring explanation; two of which were postoperative infections. Thirteen patients required an addition of normal saline through the resipump as an office procedure. Ninety-three percent of the patients and 98 percent of the partners reported satisfaction with the use of the prosthesis. Men who had a previously inserted penile prosthesis replaced with the GFS Mark II IPP preferred the GFS over the malleable and the self-contained prosthesis, but there was no conclusive preference between the different IPPs. CONCLUSIONS: This study concludes that the GFS Mark II connectorless IPP has shown few mechanical problems over a four-year period and has a good patient/partner satisfaction. This prosthesis has the additional feature of the resipump to adjust the fluid volume as an office procedure when required.

Erectile Dysfunction↗
PubMedDate not supplied

Grammont reverse prosthesis: design, rationale, and biomechanics.

Combined destruction of the rotator cuff and the glenohumeral joint may lead to a painful and pseudo-paralyzed shoulder. In this situation a nonconstrained shoulder prosthesis yields a limited functional result or may even be contraindicated. Previous constrained prostheses (ball-and-socket or reverse ball-and-socket designs) have failed because their center of rotation remained lateral to the scapula, which limited motion and produced excessive torque on the glenoid component, leading to early loosening. The reverse prosthesis designed by Paul Grammont, unlike any previous reverse ball-and-socket design, has introduced 2 major innovations that have led to its success: (1) a large glenoid hemisphere with no neck and (2) a small humeral cup almost horizontally oriented with a nonanatomic inclination of 155 degrees, covering less than half of the glenosphere. This design medializes and stabilizes the center of rotation, minimizes torque on the glenoid component, and helps in recruiting more fibers of the anterior and posterior deltoid to act as abductors. Furthermore, the humerus is lowered relative to the acromion, restoring and even increasing deltoid tension. The Grammont reverse prosthesis imposes a new biomechanical environment for the deltoid muscle to act, thus allowing it to compensate for the deficient rotator cuff muscles. The clinical experience does live up to the biomechanical concept: the reverse prosthesis restores active elevation above 90 degrees in patients with a cuff-deficient shoulder. However, external rotation often remains limited, particularly in patients with an absent or fat-infiltrated teres minor. Internal rotation is also rarely restored after a reverse prosthesis. Failure to restore sufficient tension in the deltoid may result in prosthetic instability. The design does appear to protect against early loosening of the glenoid component, but impingement of the humeral cup on the scapular neck can lead to scapular notching and polyethylene wear. This is a cause for concern, especially as the notch is often more extensive than can be explained by impingement alone. Bony lysis of the scapula may also be related to a polyethylene granuloma. Further follow-up is required to ensure that loosening does not become a problem in the long term, and it has been recommended to limit its use to elderly patients, arguably those aged over 70 years. Despite these concerns, the reverse prosthesis, based on the biomechanical Grammont concept, offers a true surgical option in several situations where only limited possibilities were previously available: cuff tear arthrosis, persistent shoulder pseudo-paralysis due to a massive and irreparable cuff tear, severe fracture sequelae, prosthetic revision in a cuff-deficient shoulder, and tumor surgery. Finally, surgeons must be aware that results are less predictable and complication/revision rates are higher in revision surgery.

Biomechanical Phenomena↗