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PubMedDate not supplied

[Posturographic study of total prostheses in the leg. Apropos of 88 patients examined].

By suppressing certain articular sensory receptors, the reconstructive surgery of joints using total prostheses modifies tonic postural activity and, by this means, alters the regulation of balance in the subjects of operation. This doubtless explains certain discrepancies between the apparently excellent results in respect of joint movement and muscle strength and poor utilisation of the joint in every day life (instability, use of sticks or failure to use the joint in walking). Drawing on the experience and basic work of specialists in posture, the authors have undertaken a study of tonic postural activity in patients who had received a total prosthesis in the lower limb, both from the clinical aspect and by graphic measurement using an electronic apparatus, the statokinesiometer. Fourteen normal subjects were tested to calibrate the apparatus and 8 patients suffering from established osteoarthritis of the hip were studied as controls. Analysis of tonic postural activity was made in 66 patients who had received total prostheses in the lower limb. The results showed significant disturbance in balance in ankle prostheses, minimal disturbance in knee prostheses and not significant disturbance in hip prostheses. Certain therapeutic implications are derived from this study.

Adult↗
PubMed2004

Removable prostheses for preschool children: report of two cases.

Dental prostheses are frequently used to avoid psychologic, speech, or swallowing problems in preschool children with considerable tooth loss. Two cases of preschool children are presented, involving multiple loss of primary teeth. The purpose of this study was to promote the correct development of the maxilla and mandible by using removable dental prostheses and to guide the eruption of the permanent molars. Removable acrylic prostheses were provided for two children, with a special metallic s-shaped handle (ansa), which guided the eruption of the first permanent molars. These prostheses were modified as the children grew. By replacing missing teeth, several oral functions were re-established, development of the maxilla and mandible was promoted, and each child could develop socially from a psychologic point of view. The use of removable dental prostheses in preschool-aged children presenting with considerable tooth loss can be a viable and successful treatment option.

Child, Preschool↗
PubMedDate not supplied

Long-term treatment outcomes in edentulous patients with implant-fixed prostheses: the Toronto study.

PURPOSE: The aim of this prospective study was to report long-term treatment outcomes (prosthetic and implant related) of edentulous patients treated with implant-supported fixed prostheses who participated in the first clinical implant study in North America. MATERIALS AND METHODS: Forty-five patients were treated with Brånemark implants supporting a total of 47 fixed prostheses (42 mandibular and 5 maxillary) between 1979 and 1984. All patients were recalled regularly for comprehensive prospective clinical and radiographic assessments. RESULTS: Thirty-one patients (33 prostheses) attended a final recall visit in 2002; 71% of patients had been followed for 20 years (range 18 to 23 years), with overall prosthetic plan and implant outcome success rates of 84% and 87%, respectively. Mean marginal bone loss around the implants after the first year of loading was small (0.05 mm/year), with high individual variations. Poor oral hygiene, smoking history, and implant position appeared to be predictors of marginal bone loss. Prosthetic maintenance was ongoing and included fractured components and replacement of prostheses; the longevity of a fixed prosthesis for this group of patients was 8.39+/-5.30 years. CONCLUSION: This study confirmed the overall long-term treatment outcome success of patients treated with fixed prostheses supported by Brånemark implants. Successful osseointegration with a small mean bone loss was maintained as study patients aged, although prosthetic maintenance was required. The latter consideration should be discussed with all patients seeking such treatment.

Adult↗
PubMed2004

[Significance and role of increased expression of extracellular matrix metalloproteinase induced in the aseptic loosening of prostheses].

OBJECTIVE: To investigate the expression of extracellular matrix metalloproteinase induced (EMMPRIN) in the interface tissue, and explore the role of EMMPRIN in the aseptic loosening of prostheses. METHODS: Immunohistochemistry was performed to characterize the EMMPRIN-expressing cells at sites of interface tissue around aseptic loosened hip prostheses in 16 cases. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to study the existence of EMMPRIN mRNA in interface tissue samples. And it was followed up by computer assisted image analysis in order to detect the A values of their expression. Synovium of hip joint of 8 femoral neck fracture were in control group. RESULTS: Strong immunostaining of EMMPRIN was found in the macrophages and fibroblasts of lining-like layers and vascular endothelium of synovial membrane-like interface tissue around loosened prostheses. Expression of EMMPRIN was significantly higher in interface tissue than the control synovium (z=-3.252, P=0.001). RT-PCR of interface tissue samples disclosed the presence of EMMPRIN mRNA of 14 cases. In interface tissue, the A value of EMMPRIN increased significantly compared to control synovium (P<0.01). CONCLUSION: Over-expression of EMMPRIN up-regulates the production of matrix metalloproteinase (MMPs) in the interface tissue. And it can promote the bone destruction around prostheses. Thereby it may be one of methods to prevent and treat aseptic loosening of prostheses by repression the biology activity of EMMPRIN.

Adult↗
PubMed2005

[Repair of orbital defects with implant-retained prostheses].

OBJECTIVE: To evaluate the clinical result of using osseointegrated implants to repair removable orbital prostheses in repairing orbital defects. METHODS: Two patients with orbital defects caused by orbital tumor were treated. Each of them got 4 implants. After average 6 months, we performed the secondary operation. After 7 weeks, we took impressions to make the implant-retained prostheses. The magnetic attachment was adopted. The prostheses were made of polysiloxane material (Factor II, Lakeside, Ariz). RESULTS: Both of the patients got the successful facial prostheses and were followed up 2 and 8 years respectively. All the implants were integrated well. There were no apparent inflammatory reactions in the soft tissue around percutaneous implants. The patients were satisfied with the facial appearance. CONCLUSION: Implant-retained orbital prostheses are safe and effective in repairing orbital defects.

Adult↗
PubMedDate not supplied

Development and long-term fate of a cellular lining in fibrous polyurethane vascular prostheses implanted in the dog carotid and femoral artery. A scanning and light microscopical study up to 53 months after implantation.

The development and long-term fate of the inner cellular lining in 72 small caliber (3 mm inner diameter) fibrous polyurethane vascular prostheses explanted from dog carotid and/or femoral arteries at times ranging from 1.5 weeks up to 53 months after implantation were studied by scanning electron and light microscopy. A continuous cellular ingrowth from the vascular stumps into the 3 cm long prostheses was observed, which eventually resulted in a complete cellular lining 6 months after implantation. No other ways of endothelialization were noted. In fully endothelialized prostheses, the cellular ingrowth extended approximately 8 mm into the prostheses and consisted of several layers of fibroblasts and smooth muscle cells, covered by a very thin endothelioid cell layer. The newly developed lining was firmly anchored onto the inner prosthetic surface by means of cellular protrusions extended into the fibrous texture of the prosthetic wall. It was concluded that under experimental conditions in the dog complete endothelialization can be obtained in fibrous polyurethane vascular prostheses and that the lining remained thin and stable throughout the observation period of 53 months after implantation.

Anastomosis, Surgical↗
PubMed2005

[Tissue reaction to breast prostheses. Periprosthetic capsular contracture].

Silicone breast prostheses prompt the development of a fibrous casing or periprosthetic capsule. Capsular contracture, due to retraction of the fibrous tissue, is the most frequent and important complication of these implants. It produces varying degrees of hardening and, in advanced cases, deformity of the breast. It has been closely related to the type of surface of the implant (smooth or textured) and with the alignment of the collagen fibers, and it has been suggested that the formation of a continuous capsule, with collagen fibers aligned in parallel and circularly around the smooth prostheses, promotes the development of concentric contractile forces that pulling in unison give rise to contracture. With microporous textured prostheses a significantly lower incidence of capsular contracture has been shown in comparison with smooth prostheses. It is believed that tissue growth within the microporous structure gives rise to multidirectional contractile forces, with a tendency to neutralize one another when their effect is added over the implant. The capsule of these implants presents a base zone composed of multiple layers of collagen fibers aligned in parallel, which might contract. However, the adherence of the microporous textured prostheses might counteract the contractile forces.

Breast Implants↗
PubMedDate not supplied

Objective clinical assessment of change in swallowing ability of maxillectomy patients when wearing obturator prostheses.

PURPOSE: Evaluation of treatment outcome is important in maxillofacial rehabilitation. Although eating is one of the oral functions that most strongly influences patients' quality of life, only a few reports exist on the objective assessment of swallowing for maxillectomy patients. The purpose of this study was to identify changes in the swallowing ability of maxillectomy patients when wearing obturator prostheses through the use of an objective clinical assessment. MATERIALS AND METHODS: The swallowing ability of 38 postmaxillectomy patients consecutively treated with obturator prostheses was objectively evaluated with the "water-drinking test" that was developed for the assessment of dysphagia patients after cerebrovascular disease. In this test, the subjects were instructed to drink 30 mL of water in one swallow. The profile was evaluated with the combination of the time required for drinking the water and the incidence of cough reflex. Statistical analysis was performed using the Wilcoxon signed-rank test, the paired t test, and the Chi-square test with StatView 5.0 for the Macintosh. RESULTS: Performance improved significantly when the patients wore prostheses (P = .0026, Wilcoxon signed-rank test). The mean drinking times without and with prostheses were 8.2 +/- 6.3 s and 5.0 +/- 3.5 s, respectively. Drinking time was shortened significantly when the prosthesis was worn (P = .0002, paired t test). The assessment of behavior and episodes revealed that the swallowing ability of the maxillectomy patients was significantly improved when a prosthesis was worn (P = .0002, Chi-square test). CONCLUSION: The swallowing ability of maxillectomy patients was quantitatively and qualitatively improved with obturator prostheses.

Aged↗
PubMed1991

[Hemodynamics of various heart valve prostheses].

Modern tilting disc and bileaflet prostheses, and bio-prostheses, perform similarly regarding pressure gradients, discharge coefficient and performance index; however, only bio-prostheses increase their opening area with increasing flow. Ball valve prostheses of the Starr-Edwards type perform less satisfactorily with higher pressure gradients and lower performance indices, which may result in less favorable long-term follow-up. Bio-prostheses show degenerative changes with increasing age which, over a period of 7-10 years, can lead to clinically relevant stenoses necessitating reoperation.

Bioprosthesis↗
PubMed1991

[Evaluation of vascular prostheses made of carbon fiber].

The whole work was aimed at experimental estimation of the healing process in case of carbon fibre vascular prostheses implanted into the abdominal aorta of a dog. The tests applied to carbon fibre woven prostheses made in the USSR. All metrological and chemical tests were performed at the Knitting Industry Main Centre for Research and Development "Tricomed" in Lódź. Experimental examinations were performed on 12 dogs. Prostheses were implanted into dog's abdominal aorta "end to the end" with the help of threads type Mersilen 4-0 or Prolen 4-0. The dogs were observed for 53 to 121 days, i.e. their behaviour, condition of the postoperative wound and presence of pulse in the femoral arteries were taken into consideration. Upon the completion of the observation autopsy was performed. Thus obtained material was fixed in 9% formalin and next various dyeing methods were applied to it. During examination in autopsy no inflammatory reactions in the tissues adjacent to implanted prostheses were discovered. In each case there was a continuous and firm adhesion of prosthesis and neighbouring inferior caval vein. A newly developed so called "neoadventitia" in the lumen of the prostheses constituted a solid and uniform film covering the wall of the prosthesis. Haematoma in the nearabout of the prosthesis was found in two cases only. Close to anastomosis ordinary clusters of lymphocytes and numerous fibroblasts as well as collagen fibre between prosthesis plexus were discovered. On the basis of the examinations performed a conclusion could be drawn, i.e. the process of healing was followed by regular structure of new aorta walls together with well developed flexible and springy fibre and neglidgeble immunological reactions.

Animals↗
PubMed1991

[The use of prostheses and traditional technics in the surgical treatment of laparocele. An experimental study].

The problem of surgical fixing for incisional hernia is still far from a final solution. Over the past few years, prostheses have been used in addition to traditional plastic surgery. The aim of this experimental study was to assess the efficacy of traditional techniques in comparison to modern methods using prostheses. For this purpose, two original experimental models were designed to assess parietal resistance. Ninety-six Wistar rats were subdivided into 4 group: 1) control; 2) "waistcoat" plastic surgery; 3) plastic surgery using a vicryl prosthesis. With the exception of rats in group 1, a lozenge-shaped section of abdominal wall was removed from all other rats and, subsequently, the wall was repaired using the above-mentioned methods. Rats were killed after 30-60-120-180 days and the abdominal walls were subjected to traction and pressure using specially designed experimental models. For the first 30 days, the walls with dacron and vicryl prostheses behaved in a similar way, and showed a greater resistance than the other two groups; but after day 120, the resistance of dacron prostheses was considerably greater than that of the other groups studied. In conclusion, plastic surgery based on the use of nonreabsorbable prostheses is now more efficacious than traditional plastic surgery in the surgical treatment of incision hernia.

Abdominal Muscles↗
PubMed1991

[Different knee prostheses and their technical problems].

Depending on whether degenerative lesions are localized to one single compartment or extend to all three compartments of the knee, and depending on the state of the ligaments (notably the cruciate ligaments) and on the presence or absence of osseous and frontal deformations, various prostheses can be used in the treatment of gonarthrosis. These prostheses fall into three main categories: (i) hinge prostheses, which are very constrained; (ii) sliding prostheses with varying degrees of constraint depending on whether or not the cruciate ligament(s) are spared, and (iii) one-compartment prostheses which replace only one of the three compartments of the knee. Each type of prosthesis has its advantages and drawbacks. Total knee replacement has become a reliable procedure which regularly provides stable and painless knees with a mean flexion angle of 110 degrees and is mainly applied, for the time being, to subjects leading a sedentary life.

Biomechanical Phenomena↗
PubMed1991

[Noise origin and noise-induced complaints after heart valve replacement with mechanical prostheses].

143 patients were investigated in order to determine whether there is a difference in the intensity of the closing click between different mechanical heart valve prostheses. 35 had St. Jude Medical (SJM), 38 Duromedics Edwards (DE), 36 Björk Shiley Monostrut (BSM) and 34 had Carbomedics prostheses implanted. Sound pressure level determined at 1 meter distance was significantly higher for the DE 33.5 +/- 6 dB(A) and BSM 31 +/- 4 dB(A) than for the SJM 24 +/- 4 dB(A) and CM 25 +/- 6 dB(A) prostheses (p = 0.0001). Valves developing higher sound pressures were more frequently audible for the patients (p = 0.0012), caused more sleep disturbances (p = 0.024) and more complaints during daytime (p = 0.07). Significantly more patients carrying such valves wished to have a less noisy valve implanted (0.0047). Symptomatic patients wear louder valves, were younger, had better hearing and were more frequently in sinus rhythm. Valve diameter correlated with the developed sound pressure level. 349 patients answered a questionnaire after valve replacement with DE (256) or BSM (93) prostheses. 5% registered their noise-related complaints as being severe, but more than one third wished to have a less noisy valve implanted. The noise created by the closing click of mechanical prostheses causes significant complaints and this factor should be considered when a mechanical valve is selected.

Adult↗
PubMed1991

[Doppler echocardiographic determination of the effective orifice area of mechanical heart valve prostheses in a flow model].

In a flow model the effective orifice areas (Ae) of 17 mechanical heart valve prostheses were determined. We measured the Ae-values of several sizes of three types of mechanical prostheses (Medtronic-Hall, St. Jude Medical, and Omnicarbon) under quasi-steady flow conditions using the continuity equation: Ae = flow/maximal transprosthetic velocity. The flow through the model could be determined exactly by directly measuring the decreasing fluid level within the feed tank, while the maximal velocities were calculated from CW-Doppler echocardiographic spectra. It was found that 1) over a range of 200-800 cm3/s Ae was constant for all prostheses and 2) in small aortic prostheses the Ae could be determined with only little scattering of the obtained values, while in large mitral prostheses there was a considerable variation within the results of repeated investigations. For example, in the 21- and 31-Omnicarbon-valves mean values of Ae were calculated as 1.41 and 4.03 cm2, respectively, with standard deviations of 0.05 and 0.49 cm2 as a result of about 70 single calculations in each valve. 3) The absolute values of Ae were smaller than those of comparable in vitro studies based on the Gorlin formula. We conclude that the effective orifice areas of prosthetic heart valves can be easily determined in a flow model by the combination of flow and Doppler echocardiographic measurements. As determinations are based on the same principle, the obtained values should clinically be referred to patients where the corresponding continuity equation for pulsatile flow is used as Ae = stroke volume/time integral of the maximal transvalvular velocity.

Aortic Valve↗
PubMed1990

Cementless total joint arthroplasty prostheses with titanium-alloy articular surfaces. A human retrieval analysis.

Surgical implants of titanium alloy (Ti-6Al-4V) have been found to be susceptible to abrasive wear, resulting in the well-known phenomenon of metallosis. In the presence of the acrylic debris generated by loose joint arthroplasty prostheses, this abrasive wear is greatly increased. However, the bone loss seen in these cases has generally been presumed to be due to the osteolytic effects of particulate acrylic, not the alloy debris, which has generally been assumed to be biocompatible. To examine the in vivo effects of titanium-alloy wear without the added presence of acrylic debris, a comprehensive analysis was made of cementless human joint arthroplasty prostheses with Ti-6Al-4V alloy surfaces articulating on ultra-high molecular weight polyethylene (UHMWPE). Specimens, including the prostheses, synovium, pseudocapsule and additional soft tissues, and periarticular bone, were retrieved from 22 hips and two knees. Specimens were examined by histologic techniques, energy-dispersive X-ray analysis, and electron microscopy. Serial sections of the implants were evaluated for tissue ingrowth. Tissues surrounding all joints implanted more than one year showed some degree of discoloration indicative of metallosis, whereas after two years the synovium was hypertrophic and villiform. Histologic evaluation showed good fixation by bony ingrowth in the vast majority of cases, although location and extent of ingrowth was dependent on numerous factors. Viability of ingrowth bone was established by fluorochrome labeling. However, despite good biologic fixation, cavitary osteolysis of the bone surrounding the implants was frequently identified. These lesions were filled with sheets of aggressive macrophages within a matrix of fibrous tissue and necrotic debris. Under polarized light the macrophages were found to be filled with alloy and polyethylene fragments of a characteristic size. Osteoblast-mediated remodeling of bone was infrequently observed. Instead, the bone was resorbed along a front in contact with the granulomatous tissues filling the cystic lesions. Visible burnishing was observed on every articular surface, with a linear relationship between wear and time implanted. By one year the surfaces were covered with a characteristic "scratch and gouge" pattern, similar on all sizes of femoral heads as well as the total knee prostheses. This study demonstrates that the combination of Ti-6Al-4V alloy and UHMWPE, when used as a bearing surface combination in total joint arthroplasty prostheses, results in excessive wear of both metal and polymer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1988

Fate of polyester arterial prostheses implanted as thoraco-abdominal by-passes in dogs: haematology, pathology, and biochemistry.

This study was designed to evaluate the haematological, pathological and biochemical characteristics of the flow surface in polyester arterial prostheses. Their implantations as thoraco-abdominal by-passes in dogs were scheduled to remain in place for periods ranging from four hours to six months. The haematologic parameters of the hosts were evaluated before implanting the prostheses and before harvesting the graft. To quantify the thrombogenicity of the flow surface, the platelet deposition and fibrinogen uptake were measured by means of an isotopic technique involving Indium-III labelled platelets and iodine-125 labelled fibrinogen. Synthesis of prostacyclin (PGI2) and thromboxane (TXA2) by the internal capsulae was determined by radioimmunoassay. The pathology was assessed according to previously described protocols. The haematologic parameters of the hosts did not alter substantially in the presence of the prostheses. The observed changes, though slight, were not pathologically significant 48 hours after implantation. Platelet and fibrin deposition was highest on the luminal surface of the prostheses 24 hours post-implantation. These decreased and became negligible after one month when the flow surface became smooth and glistening. The PGI2/TXA2 ratio of the luminal surface was much lower than that observed in native aortic tissue. These results show that the large calibre Dacron vascular prosthesis has a flow surface with a low degree of blood compatibility. The concentration of PGI2 on the newly-formed luminal surface remained low. This characteristic and the incomplete endothelialization of the luminal surface might be among the main factors that determine the high failure rate of synthetic prostheses when used as small diameter blood conduits.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

[Evaluation of scintigraphic procedures for clarifying pain conditions in hip joint prostheses].

59 patients with implanted one- or two-sided hip prostheses (n = 74) have been investigated by two different scanning techniques to detect both possible loosening of the prostheses and a possible infection as the cause of the loosening. Of the investigated prostheses 47 were loose; in 45 cases this was evidenced by the bone scan using Tc-99m-DPD, thus showing a sensitivity of 95%. Specificity was 89%. In 21 cases (45%) of loose prostheses an infection could be clinically proven. With the aid of In-111 labeled leukocyte scans, 17 of 21 cases were correctly diagnosed as infected, showing a sensitivity of 91%, while the specificity was 94%. In view of the 93% accuracy, bone scanning can be regarded as the method of choice in detecting loosening of prostheses. The 91% accuracy in proving or ruling out infection by means of the leukocyte scan is high enough to assert correct findings in most cases. The main disadvantage of this method is the very demanding technique for marking of white blood cells.

Diphosphonates↗
PubMed1988

[Causes of decreased stability of good survival results and the incidence of complications in patients with multiple heart valve prostheses].

The results of six-year follow-up of 368 patients after multiple prosthetic valve implantation (mitral and aortic prostheses in 173, mitral and tricuspid prostheses in 129, three prostheses in 36, mitral and aortic prostheses with tricuspid annuloplasty in 30) are reviewed. The mean functional class was 4.05 prior to the operation, and eventually declined to 2.1, being indicative of increased physical activity of the patients. Good results were stabilized in 61% of cases. Major causes of insufficient stability of good results were specific complications and progressive attendant heart diseases. There were no specific complications in 51% of the patients. The survival rate was 39.2%, including the intraoperative mortality rate. Long-term survival rate was 59.3%. Myocardial insufficiency, mostly occurring in patients with aortic prostheses and preoperative functional class 4 or 5, was one of the leading causes of reduced long-term survival. Therefore, patients should undergo surgery when in functional class 3, and those with aortic defects, while they are in functional class 2.

Adolescent↗