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PubMed1981

Predicting aortic valve prosthesis size. A step toward better matching of patient and prosthesis.

We have developed a simple method of predicting aortic valve prosthesis size from supravalvular aortic cineangiograms, taken in the 30 degree right anterior oblique projection, during routine diagnostic cardiac catheterization. Measurements made on the aortogram were corrected to true size by means of a 1 cm2 grid reference plate filmed at the conclusion of the catheterization. This method was utilized prospectively to predict the anulus size in 26 patients undergoing aortic valve replacement alone or as part of a more extensive procedure. The catheterization prediction of anulus size was perfectly predictive of the prosthesis size used in eight of 26 (31%) cases, within 1 mm of the prosthesis size used in 20 of 26 (77%), and within one prosthesis size in all 26 (100%) cases. Comparing the measured anulus diameter to the actual prosthesis diameter yielded r = 0.93. When both systolic and diastolic frames were available for analysis, the diastolic frame was more accurately predictive than the systolic frame (diastolic r = 0.93; systolic r = 0.88), although both yielded acceptable results. Utilization of this method has significantly altered operative plans in four patients with a small anulus. Such preoperative assessment should allow improved matching of patient and valve prosthesis and thereby yield improved long-term results in aortic valve replacement.

Adult↗
PubMed1993

[Endoscopic prosthesis insertion in the palliative treatment of malignant esophageal stenosis. (Endoscopic esophageal prosthesis)].

We report our experience with endoscopic esophageal prosthesis in the treatment of 82 patients with advanced malignant oesophageal stenosis. The cause of the stenosis was an esophageal or esophagogastric cancer in 75 cases and a bronchogenic cancer in 7 patients. In 18 cases a tracheobronchial fistula was also present. A silicone tube (Atkinson) was used in 58 patients, a polyvinyl tube (Wilson-Cook) in 22 cases and a self-expanding tube in the remaining 2 patients. There was no technical failure in the insertion of the prosthesis. A normal feeding was possible in 71 of the 82 patients (86%) within 48 after the intubation. Major complications occurred in 8 cases (9.7%), 4 patients with esophageal perforation and 4 cases with aspiration bronchopneumonia. Postoperative mortality rate was 7.3%, one patient with perforation, 3 cases with aspiration bronchopneumonia and 2 patients with sepsis. The prosthesis partially displaced in 9 cases, but could be endoscopically replaced in all of them. The displacement of the prosthesis was complete in 3 patients, one of which needed a surgical procedure to remove the tube. The prosthesis was bunged up by a solid meal bolus in 4 cases, but an endoscopic procedure was successful in removing the bolus. Therapy with laser was necessary in two cases with self-expanding prosthesis obstructed by tumoral growth. We conclude that, in malignant esophageal stenosis, the endoscopic implantation of esophageal endoprosthesis is an effective, cheap and relatively safe palliative therapeutic alternative with a low postoperative mortality rate.

Adult↗
PubMed1994

Long-term experience with controlled expansion cylinders in the AMS 700CX inflatable penile prosthesis and comparison with earlier versions of the Scott inflatable penile prosthesis.

UNLABELLED: OBJECTIVEs. To determine complication and survival rates of the AMS 700CX penile prosthesis and to compare its reliability with earlier versions of the Scott inflatable penile prosthesis. METHODS: Retrospective chart review and telephone interviews were used. RESULTS: Actual 4-year survival of the AMS 700CX device was 85%, whereas earlier versions of the device had actual 4-year survival of 46% (p < 0.0001). The observed difference in prosthesis reliability could not be accounted for by differences in patient population, surgical technique, or incidence of infections. The most significant factor that contributed to improved prosthesis survival was the lack of cylinder complications (leaks and aneurysms). CONCLUSIONS: The controlled expansion cylinders of the AMS 700CX penile prosthesis are a significant advance in reliable, low-morbidity surgical therapy for impotence.

Actuarial Analysis↗
PubMed2005

Biomechanical comparison of newly designed stemless prosthesis and conventional hip prosthesis--an experimental study.

Local bone loss after implantation of traditional stem-type prostheses remains an unsolved problem during the long-term application of total hip replacement. The stress shielding effect and osteolysis were thought to be the two main factors that result in local bone loss after prosthesis implantation. A newly designed stemless cervico-trochanteric (C-T) prosthesis was thus developed to reduce stress shielding and osteolysis caused by the implantation of conventional stem-type prosthesis. Eight synthetic femora were implanted with C-T and porous coated anatomic (PCA) prostheses. Under 2,000-Newton load, the surface strains of proximal femora were compared between the intact, PCA press-fit femora and the C-T implanted femora with three different fixation modes: two-screw fixation, three-screw fixation, and three-screw combined with cement fixation. The results revealed that stress shielding in the C-T implanted femora was significantly eliminated compared to that of the PCA implanted femora (p<0.01). No statistical difference in strain magnitude was found for the C-T implanted femora among the three different fixation modes (p>0.1). The C-T implanted femur has more physiological strain distribution. Moreover, from the C-T prosthetic characteristic design, the localized osteolysis would be also reduced due to the overall coverage of neck-trochanteric area. The newly designed C-T prosthesis may be a useful alternative to the traditional stem-type prosthesis in the future.

Arthroplasty↗
PubMed1997

New concepts -- biomechanical studies of a newly designed femoral prosthesis (cervico-trochanter prosthesis).

OBJECTIVE: A newly designed stemless (cervico-trochanter) prosthesis was developed for the purpose of reducing the incidence of the stress-shielding effect caused by the traditional stem-type prosthesis. DESIGN: Both mechanical test and three-dimensional finite element analysis were performed for comparing the differences of strain and stress distributions between the intact, C-T and PCA prosthetic femora. BACKGROUND: The stress-shielding effect and polyethylene (PE) wear debris were thought to be the main factors that resulted in local bone loss after the implantation of stem-type prostheses. In this study, we developed the new C-T prosthesis, which aimed to resolve the above-mentioned problems. METHODS: Six pairs of femora taken from human male cadavers were used to compare the strain magnitudes of intact (n = 12), C-T (n= 12) and PCA (n = 4) prosthetic femora in specific positions. Failure load tests of C-T (n = 8) and PCA (n = 12) prosthetic femora were also carried out from the load-displacement curve. The analysis of variance (ANOVA) test was used for statistical analysis. In addition, three-dimensional finite element stress analyses were performed using a commercial package, ANSYS, on a Convex 3810 computer. RESULTS: Both mechanical test and finite element results showed that the C-T prosthetic femora has a lower stress-shielding tendency than the PCA prosthetic femora (P < 0.001). The C-T prosthetic femora also withstood an average bearing load of 6312 N, which is greater than that of the PCA prosthesis at 5358 N (P < 0.01). CONCLUSIONS: The C-T prosthetic femur could withstand a higher failure load than the PCA prosthesis, which effectively reduced the incidence of the stress-shielding effect. Moreover, the particular design of the C-T prosthesis also reduced localized osteolysis because of the overall coverage of the neck-trochanteric area.

Journal Article↗
PubMed1996

The Nijdam voice prosthesis: a self-retaining valveless voice prosthesis for vocal rehabilitation after total laryngectomy.

Voice prosthesis-assisted speech rehabilitation after total laryngectomy has proven to be successful in the majority of patients and exceeds the results of traditional oesophageal speech. Nevertheless 10-30% failure rates are still reported. In part this is due to prosthesis-related problems, in particular ingrowth of Candida species in the valve-bearing parts of the devices. A new indwelling, low-resistance and valveless voice prosthesis is described; the Nijdam voice prosthesis. The device has an average device lifetime of 19 weeks which appears to be superior to other indwelling voice prostheses. Replacement indications mainly comprise leakage or increased airflow resistance. Most frequent local complications are granulation tissue and hypertrophic scar tissue formation. These occur in 12% of the patients and can easily be treated. Replacement is a simple outpatient procedure. The prosthesis is interchangeable with other types of indwelling voice prosthesis.

Equipment Design↗
PubMed1981

Functional effectiveness of a myo-electric prosthesis compared with a functional split-hook prosthesis: a single subject experiment.

The functional effectiveness of a myo-electric prosthesis with sensory feedback compared with that of a split-hook is described. Thirty independent observations were made on a single subject with a right below-elbow amputation wearing the myo-electric prosthesis and the split-hook prosthesis. Using a first order autoregressive model for making inferences about the two sets of data, the split-hook was found to be functionally better (p less than 0.001) than the myo-electric prosthesis. Functional effectiveness was defined operationally as scores on the Minnesota Rate of Manipulation Placing Test and the Smith Test of Hand Function. No predictions are made regarding the use of either prosthesis for other amputees. However clinical evidence suggested suitability of the myo-electric prosthesis with sensory feedback for some other functional tasks.

Adult↗
PubMed2005

[Femoral neck prosthesis in the case of femoral neck fracture and ipsilateral long stem-knee tumour prosthesis].

Femoral neck fracture in the case of a previously implanted ipsilateral tumour knee-prosthesis represents a challenging situation because of the long proximal stem of the knee implant. Avoiding total femur replacement, we implanted a femoral neck prosthesis (Eska Cut 2000) in a 65 year old patient to preserve as much of the femur free of implant as possible, minimizing the risk of a periprosthetic or interprosthetic fracture. At 2.5 years postoperatively, there were no signs of loosening, migration or periprosthetic fracture with a good functional result. In our case, the femoral neck prosthesis avoided the implantation of a total femur replacement. Nevertheless, this prosthesis must be considered critically and cannot be recommended as the standard implant for femoral neck fracture in the case of an ipsilateral long stem-knee prosthesis.

Aged↗
PubMed1980

[Aortic and mitral monovalvular replacements. Comparison of the ball prosthesis of Starr-Edwards (1260-6120) and the tilting disc prosthesis of Bjork-Shiley. Series of 390 patients].

The evaluation of short and long term replacement by the Björk-Shiley tilting disc prosthesis (BS) and by the Starr-Edwards ball and cage prosthesis (SE) was carried out on a series of 390 consecutive patients. In mitral replacement, operative mortality rate (SE 5.9 P. 100 - BS 4.8 P. 100), 5 year actuarial survival (SE 79.8 P. 100 +/- 3.8 P. 100 - BS 86.3 P. 100 +/- 9 p. 100) incidence of thromboembolic complications and valvular thrombosis (SE 1.6 P. 100 - BS 1.3 P. 100) as well as the degree of post-operative improvement were virtually identical in both types of prosthesis. Likewise, in aortic valve replacement, operative mortality rate (SE 4 p. 100 - BS 3.2 p. 100), 5 year survival (SE 82 +/- 7.8 P. 100 - BS 86 +/- 3.3 p. 100) incidence of thromboembolic complications (SE 2.2 p. 100 - BS 1.8 p. 100) and the degree of post-operative improvement were not statistically different. However, the incidence of sudden death was statistically smaller with a BS prosthesis than with a SE prosthesis (respectively 1.6 p. 100 and 6.9 p. 100).

Actuarial Analysis↗
PubMed2003

A mobile-bearing total knee prosthesis compared with a fixed-bearing prosthesis. A multicentre single-blind randomised controlled trial.

Before proceeding to longer-term studies, we have studied the early clinical results of a new mobile-bearing total knee prosthesis in comparison with an established fixed-bearing device. Patients requiring bilateral knee replacement consented to have their operations under one anaesthetic using one of each prosthesis. They also agreed to accept the random choice of knee (right or left) and to remain ignorant as to which side had which implant. Outcomes were measured using the American Knee Society Score (AKSS), the Oxford Knee Score (OKS), and determination of the range of movement and pain scores before and at one year after operation. Preoperatively, there was no systematic difference between the right and left knees. One patient died in the perioperative period and one mobile-bearing prosthesis required early revision for dislocation of the meniscal component. At one year the mean AKSS, OKS and pain scores for the new device were slightly better (p < 0.025) than those for the fixed-bearing device. There was no difference in the range of movement. We believe that this is the first controlled, blinded trial to compare early function of a new knee prosthesis with that of a standard implant. It demonstrates a small but significant clinical advantage for the mobile-bearing design.

Aged↗
PubMed2006

Presurgical implant-supported prosthesis: technique for cementation of a definitive prosthesis immediately after surgery.

A fixed prosthesis, supported by implants, was fabricated prior to surgery and cemented with passive fit immediately after placement of 14 implants in the mandible. The prosthesis was constructed before implant surgery on a plaster cast that precisely reproduced the patient's hard and soft tissues. The cast was built using a method that allowed the transfer of hard and soft tissue anatomy from computerized tomograms. A rigid surgical stent, cast in gold, was used to place the implants into prosthetically ideal positions under three-dimensional control. The prosthesis was placed immediately after implant placement, using an occlusion-driven method, which avoided the need for occlusal adjustments to the prosthesis.

Cementation↗
PubMed1998

Prosthesis evaluation questionnaire for persons with lower limb amputations: assessing prosthesis-related quality of life.

OBJECTIVE: To develop a self-report questionnaire for persons with lower limb amputations who use a prosthesis. The resulting scales were intended to be suitable to evaluate the prosthesis and life with the prosthesis. The conceptual framework was health-related quality of life. DESIGN: Multiple steps of scale development, terminating with test-retest of the Prosthesis Evaluation Questionnaire (PEQ) by mail. SOURCE OF SAMPLE: Records from two Seattle hospitals. PATIENTS: Ninety-two patients with lower limb amputations who varied by age, reason for amputation, years since amputation, and amputation level. MAIN OUTCOME MEASURES: The 10 scales used were 4 prosthesis function scales (Usefulness, Residual Limb Health, Appearance, and Sounds), 2 mobility scales (Ambulation and Transfers), 3 psychosocial scales (Perceived Responses, Frustration, and Social Burden), and 1 Well-being scale. Validation measures were the Medical Outcomes Study Short Form-36, the Social Interaction subscale from the Sickness Impact Profile, and the Profile of Mood States-short form. RESULTS: Nine PEQ scales demonstrated high internal consistency. All met test-retest criteria for comparing group results. Validity was described based on methods used to gather original items, distribution of scores, and comparison of scores with criterion variables. CONCLUSIONS: The PEQ scales displayed good psychometric properties. Future work will assess responsiveness of PEQ scales to changes in prosthetic components. We conclude that they will be useful in evaluation of prosthetic care.

Activities of Daily Living↗
PubMed2001

[Interpositioned metallic prosthesis for hallux rigidus: review of 42 cases with a metatarsophalangeal prosthesis].

PURPOSE OF THE STUDY: We report outcome at a mean 4.8 years follow-up in 42 patients with hallux rigidus treated by metatarsophalangeal interposition thin prosthesis flat concave with a lateral capsular fixation. MATERIALS AND METHODS: The 42 patients were treated from 1987 to 1997. Sixtine prostheses were implanted for osteoarthritis was grade I (n=2), grade II (n=28), and grade III (n=12). Groulier's clinical criteria and Regnauld's radiologic criteria were used to assess outcome. RESULTS: We observed 22 very good, 12 good, 4 fair, and 4 poor results. There was no significant modification in the forefoot morphology. DISCUSSION: The Sixtine prosthesis provided a global improvement in pain and motion though there was an important difference between patients with grade I and grade II osteoarthritis, who experienced major improvement, and those with grade III disease. A good overall result requires proper prosthetic centering. Subluxation or translation does not appear to be compatible with good results. Among 3 cases with overt dislocation, 1 recovered an acceptable articular space with a good overall result. Two poor results and 3 fair results were observed in patients with condensation of the phalangeal base. These bone condensations appeared in postoperative Egyptian feet. The Sixtine prosthesis may protect the interphalangeal articular space of the great toe, avoiding damage and rearward displacement of sesamoid bones. It ensures primary stability and may be left in place. CONCLUSION: We found that the Sixtine prosthesis is best indicated in hallux rigidus patients with grade II osteoarthritis.

Adult↗
PubMedDate not supplied

The inverse prosthesis as a revision prosthesis in failures of shoulder hemiarthroplasty.

The authors describe their series of seven cases of complications and failures of shoulder hemiarthroplasty that were submitted to revision surgery involving an inverse prosthesis. This prosthesis has for some time now been indicated in elderly patients with arthropathy caused by rupture of the cuff. In our cases this prosthesis was implanted in patients who had undergone shoulder hemiarthroplasty for fracture and for arthrosis. The Constant score was used for pre- and postoperative evaluation. Results at mid-term, from 2 to 4 years, indicate evident improvement in Constant score that rose from a mean of 23.14 preoperatively to a mean of 49.14 postoperatively. Despite the limited follow-up the authors suggest the use of the inverse prosthesis as an effective alternative solution in shoulder arthroplasty revision surgery.

Aged↗
PubMedDate not supplied

[The relationship between the presence of Candida colonization in the oropharynx and on the Blom-Singer voice prosthesis and its effect on the length of prosthesis use].

OBJECTIVES: We investigated the effect of oropharyngeal Candida colonization on the contamination of the Blom-Singer voice prosthesis and its lifetime. PATIENTS AND METHODS: The study included 26 male laryngectomized patients (age range 45 to 76 years) in whom the Blom-Singer low-pressure prosthetic valve inserted required removal due to improper functioning. All patients had postoperative radiotherapy. Patients who had nystatin therapy were excluded. At the time of removal, cultures were obtained from the esophageal end of the prosthesis and from the oropharynx to be examined with regard to Candida growth. RESULTS: Candida colonization was recovered from the cultures obtained on 20 prostheses (77%) and from 14 oropharyngeal specimens (54%). The presence of oropharyngeal colonization was always associated with that on prostheses. The average lengths of prosthesis use were 5.7 months (range 4 to 9 months) and 6.2 months (range 3 to 10 months) in patients with and without positive oropharyngeal Candida colonization, respectively (p>0.05). CONCLUSION: The results suggest that the presence of oropharyngeal Candida colonization has no effect on the prosthesis lifetime.

Aged↗
PubMed1977

[Cephalic prostheses in femoral neck fractures: Comparison of immediate complications and late functional results of Moore's prosthesis and sealed prosthesis].

In this study the authors compared the mortality of fractures of the neck of the femur treated by femoral prostheses with early walking compared with trochanteric fractures treated by a nail plate and non-weight bearing activity for 2 to 3 months. The mortality in the two series (about 20 per cent) was the same. The authors then compared two series of fractures of the femoral neck, one treated by Moore's prosthesis without cement and the other by an alternative type of femoral prosthesis with cement. They conclude that the mortality was the same in the two groups but that the cemented prosthesis had better functionnal results. Long-term tolerance of the acetabulum was the same in the two types of prosthesis. Total hip replacement is very rarely indicated in recent fractures of the femoral neck.

Aged↗
PubMed1989

[Selection of valve prosthesis, reoperation and late result--surgical technique of reoperation with Björk-Shiley prosthesis].

Late result of Björk-Shiley prosthesis selected in the aortic and mitral position for valve replacement was reviewed on 222 cases in our 10 years clinical experience. Late survival was 93.8% (5 yrs), 83% (10 yrs) in the aortic position, 94% (5 yrs) and 80% (10 yrs) in the mitral position. Valve-related complication by Björk-Shiley prosthesis was very low in incidence as compared with that published by other institution with respects to thromboembolism, prosthetic valve endocarditis, reoperation, anticoagulation-related bleeding. Inflammatory aortic valve disease which developed valve detachment in the aortic position with Björk-Shiley valve was treated with double-suture technique in the aortic annulus and fixation of the graft with the inside of sinus of Valsalva, en-bloc reconstruction with composite graft using Björk-Shiley valve inside of the sinus Valsalva without touch to coronary ostium. The other surgical procedure was translocation method using Björk-Shiley prosthesis. Our clinical results suggest that Björk-Shiley prosthesis is still recommended in the aortic and mitral positions from low incidence of valve-related complication and good late survival.

Adult↗