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At least 73 records · Page 4Linked to original sources
PubMed1982

A cementless system of total hip prosthesis. Experimental studies on total hip prosthesis in dogs.

It is essential that the prosthetic material should not be harmful to the human body, it should be strictly fitted to the body and it should have sufficient durability. To investigate those conditions of an artificial joints as mentioned above, it is important to have experimental studies using a model of the artificial joint in animals instead of a simulator. The authors have developed their own total hip prosthesis for a dog since 1970. These prostheses were fixed to the bone without bone cement. These dogs were killed periodically from 8 weeks to 3 years after surgery of total hip replacement. Not only were pathohistological studies on the joint capsule and bony tissue of the femur surrounding the prosthesis performed, but also scanning electron microscopic examination on capsule and the surface of the prosthetic head were performed. The results were excellent. Ther was no loosening or wear when the new type of acetabular socket with large spikes was used. On the other hand, in the case of the old type socket with its smooth surface and smaller spikes, loosening of the socket and prosthetic stem occurred within one year after surgery.

Animals↗
PubMed2007

Gait assessment in patients with thrust plate prosthesis and intramedullary stemmed prosthesis implanted to each hip.

INTRODUCTION: There has not been any study regarding comparative gait analysis in patients with intramedullary stemmed prosthesis (ISP) and thrust plate prosthesis (TPP) implanted to each hip. PATIENTS AND METHODS: Four patients (three females and one male) who had undergone operation due to coxarthrosis were selected. The mean age was 60.5 (37-78) years. TPP and ISP had been implanted to the left and right hip, respectively, in three patients, and one patient received TPP to the right and ISP to the left hip. Gait was analyzed with a BTS Elite System consisting six cameras and two Kistler force plates using Helen Hayes marker set to assess the gait parameters. The clinical outcome was also evaluated according to Harris hip score (HHS). RESULTS: The average HHS was 95.0 (82-100) points after a mean follow-up of 45.0 (30-50) months for TPP and 94.5 (80-100) points after a follow-up of 60.0 (14-122) months for ISP. Neither of the HHS scores and follow-up time nor gait parameters obtained from the TPP-implanted side were statistically different when compared to those of the ISP-implanted side. CONCLUSION: TPP and ISP as the implants with their own biomechanical specifications did not produce any remarkable difference in gait.

Adult↗
PubMed1996

The prosthesis salvage operation: immediate replacement of the infected penile prosthesis.

PURPOSE: We describe our experience with salvage of the infected penile prosthesis at initial presentation in 11 patients. MATERIALS AND METHODS: All patients with prosthesis infection who presented since 1991 were considered for salvage surgery. Contraindications to a salvage operation included necrotic infections, diabetic patients with purulence in the corporeal bodies, rapidly developing infections and erosion of the device cylinders. RESULTS: In 1 patient in this group a salvage attempt was repeated after re-infection, for an overall success rate of 91%. Mean followup for the group was 21 months (range 9 to 42). Staphylococcus epidermidis was the infecting organism in 75% of our patients. CONCLUSIONS: Our experience demonstrates the safety and advantages of the immediate salvage technique.

Adult↗
PubMed2000

Postoperative exercise tolerance after aortic valve replacement by small-size prosthesis: functional consequence of small-size aortic prosthesis.

OBJECTIVES: The objective of this study was to determine whether a small-size valve prosthesis contributes to exercise intolerance, as assessed by VO2 measurement during an exhaustive cycle ergometer exercise. BACKGROUND: The determinants of exercise capacity after mechanical aortic replacement are not well known. The selection of small valve sizes has, however, been described as an independent predictor of exercise intolerance as assessed by exercise duration. Maximal oxygen uptake (VO2max) is a good index of exercise tolerance. METHODS: Fourteen patients were eligible, with a mean age of 62 +/- 6 years. Before surgery, the mean left ventricular ejection fraction (LVEF) was 73 +/- 8%. Two valve types with small diameter (19 to 21 mm) were used: Medtronic Hall and St Jude Medical. A healthy sedentary control group (n = 14) paired for age, weight and size was constituted. After one year of follow-up, cardiorespiratory tests were performed. In addition, the gradients through the prostheses were determined by continuous pulse Doppler at rest and immediately after the cardiorespiratory test. RESULTS The exercise tolerance was not significantly different between the control group and patient group: VO2 peak (21.7 vs. 20.4 ml/kg/min; p = 0.42), workloads (115 vs. 93 W; p = 0.13) and ventilatory parameters were similar. The mean and peak gradients at rest and during exercise were not correlated with VO2max. CONCLUSIONS: Valve replacement by small aortic prosthesis does not seem to be a factor of exercise intolerance as assessed by VO2max in patients without LVEF dysfunction before surgery.

Aged↗
PubMed2002

Ingrowth of aorta vascular cells into basic fibroblast growth factor-impregnated vascular prosthesis material: a porcine and human in vitro study on blood vessel prosthesis healing.

OBJECTIVE: One of the most life-threatening vascular diseases is rupture of an abdominal aneurysm. The conventional treatment is based on surgical reconstruction. An alternative treatment is endovascular aneurysm repair (EVAR). Despite many advantages, one of the problems of EVAR is endoleakage from deficient healing between the aortic neck and the fabric of the endograft. We hypothesize that better healing, achieved with induction of vascular cell ingrowth into the graft material, would lead to better graft healing. METHODS: Both pig aorta and human normal and aneurysmal aortic wall were used for organ cultures. Various growth factors were evaluated for the potential to induce intimal hyperplasia (ie, platelet-derived growth factor, vascular endothelial growth factor, and basic fibroblast growth factor [bFGF]). After the most potent growth factor had been selected, a vascular prosthetic material (Dacron fabric) impregnated with collagen and heparin was incubated with this growth factor. Impregnated pieces of Dacron were fixated on top of the aortic organ cultures for study of ingrowth of the neointima formation into the graft material. RESULTS: bFGF was the most potent growth factor to induce neointima in aortic organ cultures. The pieces of impregnated Dacron had a release of 5 ng/24 h of bFGF for a period of at least 28 days. With fixation on top of the aortic organ cultures, the impregnated Dacron was capable of inducing neointima formation and ingrowth of the neointima into the graft material after 28 days. CONCLUSION: We showed that a Dacron prosthesis impregnated with collagen, heparin, and bFGF is capable of inducing graft healing in our in vitro model, the aortic organ cultures of pig and human aortas. These results suggest that the problem of endoleakage with EVAR may be solved with a perfect proximal healing between the aortic wall and the prosthesis.

Animals↗
PubMed1986

Long-term follow-up in 262 patients after aortic valve replacement with the Lillehei-Kaster prosthesis. Overall results and prosthesis-related complications.

A follow-up was carried out in 262 patients after aortic valve replacement with the Lillehei-Kaster prosthesis. One hundred and ninety-one males and seventy-one females with a mean age of 53 years provided a total of 1385 observation years. The operative mortality was 7.3%. The long-term survival rates for the total series amounted to 74% after 5 years and 61% after 9 years. The great majority of survivors showed a marked improvement in functional capacity and a significant decrease in heart volume. Angina pectoris disappeared in 76 out of 79 patients, and exertional syncope vanished in 61 out of 62 patients. All patients received long-term anticoagulant treatment. The percentage of patients free from thromboembolic events amounted to 90 +/- 2% after 9 years, and the percentage free from valve related morbidity and mortality was 82 +/- 3% after 9 years. Only one instance of valve thrombosis was seen, and fracture of the prosthesis was never encountered. These results compare very favourably with those obtained with the Starr-Edwards or the Björk-Shiley prostheses.

Angina Pectoris↗
PubMed1987

Long-term follow-up in 54 patients after combined mitral and aortic valve replacement with the Lillehei-Kaster prosthesis. Overall results and prosthesis-related complications.

A follow-up study was carried out in 54 patients after combined mitral and aortic valve replacement with the Lillehei-Kaster prosthesis. Twenty-two males and thirty-two females with a mean age of 54 years provided a total of 272 years of observation. The operative mortality was 16.7%. The long-term survival rates were 67% after 5 years and 55% after 8 years. The great majority of survivors showed a marked improvement in functional capacity and a significant decrease in heart volume. In spite of long-term anticoagulant treatment thromboembolic incidents were the most frequent valve-related complications. The percentage of patients free from valve-related morbidity and mortality was 75% after 8 years. Valve-related death accounted for 4% of all deaths. Fracture of the prosthesis was never encountered. These results compare favourably with those obtained with the Starr-Edwards' or the Björk-Shiley prostheses.

Aortic Valve↗
PubMed2003

Medical devices; reclassification of the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis and the knee joint femorotibial (unicompartmental) metal/polymer porous-coated uncemented prosthesis. Final rule.

The Food and Drug Administration (FDA) is announcing that it has reclassified two fixed-bearing knee joint prostheses, the knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace a knee joint, and the knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis, which is intended to be implanted to replace part of a knee joint. FDA has reclassified the devices from class III (premarket approval) into class II (special controls). The special control that will apply is a guidance document entitled "Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA." The agency is reclassifying these devices into class II because special controls, in addition to general controls, will provide reasonable assurance of the safety and effectiveness of the devices, and there is sufficient information to establish special controls. The agency is also announcing that it has issued an order in the form of a letter to the Orthopedic Surgical Manufacturers Association (OSMA) reclassifying the devices.

Device Approval↗
PubMed2005

Poststapedectomy hearing gain: comparison of a Teflon (fluoroplastic ASTM F 754) prosthesis with a Schuknecht-type wire/Teflon prosthesis.

We conducted a retrospective study to compare poststapedectomy hearing gain in study-eligible patients who had received a Teflon (fluoroplastic ASTM F 754) prosthesis (study group; n = 76) with hearing gain achieved in a matched group (by age, sex, and degree of hypoacusis) of patients who had received a Schuknecht-type wire/Teflon prosthesis (control group; n = 70). All procedures had been performed by the authors at our institution between Jan. 2, 1994, and Dec. 31, 1997. Airway averages at low, medium, and high frequencies were estimated on the basis ofpre- and postoperative audiologic evaluations, as were total air-bone gaps at 7 frequencies between 125 and 8, 000 Hz. We found that the study group achieved a significantly greater degree of hearing gain at 125 and 250 Hz and significantly better closure of the air-bone gap at 250, 500, 1,000, 2,000, and 4,000 Hz. The hearing outcomes among patients in the study group were excellent.

Adolescent↗
PubMed2006

[The treatment of abdominal aortic aneurysms by use of endovascular prosthesis and classic vascular prosthesis].

The abdominal aortic aneurysm is a dilatation of infrarenal part of aorta. Its ethiology is still unknown. An infection and congenital disorders of conjunctive tissue are regarded as the main risc factors. Other factors could be a perimural thrombus and elastin and colagen degradation. It's not proved that atheromatosis is a risc factor. The disease concerns mainly the old males. Not treated aneurysm grows until rupture. The aneurysms are usually asympthomatic. Majority of them are found incidentally. Ultrasonography and computed tomography are used to extended diagnosis. The open surgery or endovascular surgery are only possible ways of treatment. The aneurysm with diameter over 55 milimeters, sympthomatic or rupted is an indication for surgery. The aim of the open surgery is implantation of the vascular prosthesis into retroperitoneal space. Endovascular method consist in placement of stent-graft in the lumen of aneurysm through small incision in a peripherial vessel. Stent-graft consists of metal chassis covered by classic vascular prosthesis. This method still requires the long-term assessment.

Aortic Aneurysm, Abdominal↗
PubMed1991

[Sled prosthesis, rotating knee and hinge prosthesis: St. Georg model and ENDO-model. Differential therapy in primary knee joint arthroplasty].

During the last 20 years the surgeons at the ENDO Klinik in Hamburg have implanted more than 7,000 cemented primary knee prostheses of their own design, formerly the St. Georg models and now the ENDO models. The sled prosthesis, rotating knee and hinge prosthesis are each stabilized to a different degree. The indication depends on the type of deformity, the disease. affecting the knee and the type of patient. As a result of our experience with the three systems they are now implanted in the ratio of 30:60:10, and we are convinced that in order to treat all problems encountered in diseased knees it is essential to have different prostheses with various degrees of stabilization.

Evaluation Studies as Topic↗
PubMed1991

[Thrombosis of mechanical heart valve prosthesis. Value of transesophageal echocardiography in the study of mitral valve prosthesis].

Forty-three consecutive patients with mechanical valve prostheses underwent transthoracic and transoesophageal echocardiography for suspected thrombolic prosthetic valve dysfunction. The results of these investigations were compared with those of cineradiography and the clinical outcome. The diagnosis of thrombosis was retained in 11 of the 43 patients (10 mitral and 1 aortic valve prostheses). The transthoracic Doppler echo was clearly abnormal in 6 of the 11 cases. Transoesophageal echo was of essential value in all cases but one, showing abnormal movement of the mobile element and/or a paraprosthetic thrombus. The cineradiography gave false negative results in 6 cases. In conclusion, these cases underline the undeniable value of transoesophageal echocardiography in occlusive or non-occlusive thrombosis of a mitral valve prosthesis. This investigation should be undertaken whenever there is the least suspicion of thrombosis of the prosthesis.

Adult↗
PubMed1990

[The use of high-field magnetic resonance in the follow-up of patients with mechanic aortic valve prosthesis and composite aortic tubular prosthesis].

Eleven patients who had undergone cardiac surgery were studied by means of high-field MR imaging (1.5 T). Six patients had had aortic root and valve replaced with a Björk-Shiley (BS) composite tubular aortic graft prosthesis for acute dissection of ascending aorta. In the other 5 patients with rheumatic calcific aortic disease, the valve had been replaced with a BS prosthesis. As a whole, MRI studies were 14. Previous evaluations of magnetic field effects had seem carried out ex vivo on both BS valves and BS composite prostheses, on surgical ligation clips (Tantalium and Stainless) and on stainless wires for sternal closure. In 4 patients (2 BS composite grafts and 2 BS valves) MRI diagnosed chronic dissection of both arch and descending aorta. In 1 of them, with a BS valve, associated localized acute dissection of ascending aorta was observed. In 3 patients with BS composite grafts, MRI revealed pseudo-aneurysms (including a thrombosed one) at the graft level. In one case MRI was repeated 4 times and was very helpful in monitoring the pseudo-aneurysm. MRI showed pericardial hematoma in 2 patients with BS grafts and paravalvular abscess in a case with BS valve. In one patient with BS valve fast-imaging MR revealed severe aortic regurgitation. No adverse reactions were demonstrated on MR images of prosthetic implants. MRI artifacts were insignificant with the spin-echo technique, while the fast-imaging technique showed clear image distortion at the valve level.

Adult↗
PubMed1981

Total knee prosthesis. Evolution of the principles and technique and initial results obtained with the total-condylar knee prosthesis "with posterior stability".

The principles and details of the surgical technique for the insertion of total knee prostheses are presented, in particular the methods of dealing with the soft tissues, the correction of deformities, and the sequence and details of making the bone sections. The authors deal in detail with the technical characteristics of their modification of the Total-Condylar prosthesis "with posterior stability" and discuss its advantages over the traditional design. The main advantages are increased range of movement and better functional capacity, stability, and distribution of load on the tibial component. No disadvantages have yet been encountered, so the authors recommend the use of this prosthesis in all cases, rather than only in selected cases.

Arthritis, Rheumatoid↗
PubMed1995

[Infected hip joint prosthesis. Viewpoints for 1-stage and 2-stage prosthesis exchange].

When treating an infected hip prosthesis, there are a number of medical, technical and biomechanical considerations. No ideal solution for all problems is available. In individual cases an optimal compromise must be found. The means for curing the infection and the one for maintaining hip stability can counteract each other. Basically, three options are available: removal of the prosthesis without replacement and one- or two-stage replacement. With all three options thorough surgical debridement is vitally important. The introduction of antibiotic cement and cementless titanium implants, together with very effective local antiseptics, has remarkably improved our treatment of this problem. Therefore, removal of infected prostheses without replacement is not as well accepted now as it has been in the past.

Anti-Bacterial Agents↗
PubMed1994

[Rescue of infected penile prosthesis: initial experience with prosthesis conservation].

Fitting a penial prosthesis has become an effective procedure to treat sexual impotence. However, its main complication, infection, remains a relatively frequent problem which forces the implant removal with the resulting treatment failure. This paper summarizes our early experience in 4 patients with infected penial prosthesis, who were treated by correcting the patient's general status, adequate antibiotic treatment, and deep and regular curing of the infected area. In these 4 patients, we managed to preserve the implant, achieving an adequate functional and cosmetic result. The paper discusses the pathophysiological mechanisms which would explain these improvements and points to the eventual indications and contraindications of the treatment. Finally, a recommendation is made to use this treatment with caution since our experience was still preliminary.

Humans↗
PubMed1994

The 'Allan Johnson' voice prosthesis. A modification of the Bivona voice prosthesis for immediate post-fitting aphonia after secondary tracheo-oesophageal puncture.

The combination of a narrow oesophageal lumen and a hypertonic pharyngo-oesophageal (P-E) segment following laryngectomy and secondary tracheo-oesophageal puncture (TEP) can cause obstruction of a voice prosthesis and consequently prevent phonation. The 'Allan Johnson' modification of the Bivona voice prosthesis incorporates a stainless steel slide and has been successfully used to remedy such a circumstance.

Aphonia↗