Substitution of an injured finger joint by silicone rubber prosthesis]

Between 1973 and the first semester of 1975, on the injured and destroyed digital articulation 27 patients have been operated on by means silicon rubber prosthesis of Swanson type. The prosthesis plasty and the field of its use are shortly resumed, pointing out the importance of its adaptation on the injured articulation. The operative technique is described, as well as the results obtained and the aspects of the evaluation are discussed. The results obtained with the silicon rubber prosthesis are very promising. In the case of failure arthrodesis may be performed at any time.     

乳晕切开式微小硅凝胶假体隆乳术

目的：采用乳晕切开式小切口微小硅凝胶假体组合隆乳30例,回顾分析·临床手术体会。方法：乳晕下缘弧形切口,2.0～2．5cm,切至乳腺被膜并于其浅面向下潜行分离至乳腺下缘,沿乳腺下缘横行切开并分离乳腺后假体腔隙,严密止血,植入微小硅凝胶假体。结果：术后均无感染和血肿发生,乳房外形满意,无两侧不对称现象发生,切口瘢痕隐蔽不显见,无包膜挛缩复发,手感良好。结论：乳晕切开式微小凝胶假体组合隆乳是一种效果良好的隆乳方法。     

Experimental studies of a nonwoven vascular prosthesis for use in small arteries

We have developed a nonporous, 3-layered laminated vascular prosthesis made of a new nonwoven cloth. Examination of its physical properties and stress relaxation curve showed that the new prosthesis is strong enough to be used as a vascular substitute and compares favorably with human arteries. Animal experiments showed that the nonporosity of the prosthesis did not adversely affect neointima formation. The prosthesis was implanted in the abdominal aorta of 70 dogs for up to 6 years and had a patency rate of 94.3%. The grafts remained elastic and pliable without aneurysmal dilatation even after prolonged use. Studies using light microscopy and scanning electron microscopy showed that a thin, smooth neointima was formed on the inner surface of the prosthesis. The velourlike surface structure of the nonwoven cloth appeared to form a good foundation for deposition of fibrin and formation of the neointima. On the basis of our encouraging experimental results, we have used the new prosthesis for reconstruction of the peripheral arteries in 10 patients, but the followup period has been too short for proper evaluation.

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Résumé Nous avons mis au point une prothèse vasculaire en matériau non tissé, non poreuse, constituée de 3 feuillets. L'étude de ses propriétés physiques et de sa courbe de distension à l'effort montre que ce nouveau matériau est suffisamment résistant pour être utilisé comme prothèse vasculaire; ses propriétés sont comparables à celles des artères humaines. L'expérimentation chez l'animal a prouvé que le caractère non poreux de la prothèse n'empêche pas la formation d'une néo-intima. La prothèse a été implantée dans l'aorte abdominale de 70 chiens avec un follow-up allant jusqu'à 6 ans: 94.3% des greffes restent perméables. La prothèse reste, même après longtemps, élastique et pliable, sans formation anévrismale. En microscopie photonique et électronique, on voit, sur la face interne de la prothèse, une néo-intima fine et lisse. La surface type velours de la prothèse non tissée semble constituer une bonne base pour le dépôt de la fibrine et la formation de la néo-intima. Etant donné ces résultats expérimentaux encourageants, la prothèse a été utilisée pour reconstruire les artères périphériques de 10 malades. Le follow-up est actuellement trop court pour une évaluation valable.

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Presented at the XXVIIth Congress of the Société Internationale de Chirurgie, Kyoto, Japan, September 3–8, 1977.     

Liquid silicone as a lunate prosthesis

Eleven patients with lunatomalacia were treated by excision of the lunate and instillation of liquid silicone. The silicone vulcanised and formed an in-situ molded prosthesis. The patients were reexamined after a mean of 7.1 years. Four patients were pain-free and two had pain only at work; three had not been improved by the operation and two had undergone arthrodesis. The patients with good results all belonged to group IV pre-operatively. Surprisingly, no patient showed any sign of silicone synovitis, although all the prostheses except one had either fractured or deformed. The reasons for this are discussed and the indications for the operation established.     

口内双侧横行小切口隆颏术

目的:探求一种通过口内双侧横行小切口使假体置入更加方便准确、减轻术中损伤及术后并发症的隆颏手术新方法。方法:根据颏部解剖结构特点,采用口内双侧粘膜上横行小切口,切口定位于双侧尖牙下方距唇龈沟5mm处,长约8mm。横行切开粘膜及粘膜下组织,分别从两侧粘膜切口纵行向下钝性分离肌层至骨膜,用剥离子在骨膜下剥离拟置入假体腔隙,假体置入后肌层及粘膜分层缝合。结果:笔者采用该切口进行硅胶假体置入隆颏术共3例,切口均Ⅰ期愈合,未出现明显术后并发症。随访1～6个月,均获得满意效果。结论:采用经口内双侧横行小切口进行硅胶假体隆颏术对矫正McCarthyⅠ型轻度小颏畸形可获得满意术后效果,且保留颏部肌肉完整性并避开颏神经,创伤小,有利于减少术后并发症等优点。     

Development of a mouse model for evaluation of small diameter vascular grafts

BACKGROUND: It is estimated that 80,000 individuals are unable to undergo life or limb saving bypass surgery because of inadequate small caliber synthetic vascular grafts. The use of tissue engineering methods has been proposed as a potential means of creating improved vascular conduits. We have developed a severe combined immunodeficiency (SCID) mouse aortic interposition model for initial evaluation and screening of small diameter vascular conduits in vivo. METHODS: Fifteen small diameter vascular conduits, approximately 1 mm in diameter and 10 mm in length, were implanted as infrarenal aortic interposition grafts for 1 to 35 days. Eight grafts were constructed using a decellularized ovine arterial tissue as a scaffold. Seven grafts were constructed from silastic tubing. Four grafts were composed of Polyurethane, and two were made of expanded polytetrafluroethylene. To explore noninvasive means of evaluating patency, grafts were selectively imaged using ultrasound and micro-computed tomography. RESULTS: All grafts were patent immediately post-operatively and at time of sacrifice. All imaging modalities were able to visualize the grafts and confirm patency. All specimens were sent for histology to evaluate neotissue formation and to correlate radiographic morphology with histological morphology. CONCLUSIONS: The use of the SCID mouse model for initial evaluation of small caliber grafts is feasible and provides a cost effective rapid screening model with the added advantage of being able to use human cells in further studies.     

Optimal prosthetic graft design for small diameter vascular grafts

Autogenous vein and arterial grafts, such as great saphenous veins and internal mammary and radial arteries, remain the gold standard conduits for vascular reconstruction. Expanded polytetrafluoroethylene (PTFE) grafts, which exhibit little inflammatory and thrombogenic reactivity, are the most commonly used material of choice for small diameter vascular grafts when autogenous grafts are not available. Several modifications of the basic graft have been attempted to enhance graft healing of expanded PTFE grafts, and little but definite experimental and clinical improvement has been achieved so far. The technique of vascular tissue engineering, in combination with stem cell research, may hold the key for the creation of a practical and successful small diameter prosthetic graft.     

Evaluation of microvascular prosthesis of microporous polytetrafluorethylene

The present study assesses the patency and tissue response to a microvascular graft of expanded polytetrafluorethylene (PTFE) of internal diameter 1 mm, used to bridge a surgical gap in the abdominal aorta of 18 Sprague-Dawley rats. No anticoagulants were given. The prostheses were excised at autopsy at intervals from 3 days to 3 months postsurgery. Seventy-eight percent of the prostheses remained patent, some up to 3 months. Histological evidence of a functional prosthesis was recognized in the presence of a constant adventitial capsule to the prosthesis, without evidence of obstructing luminal material. Some cellular infiltration of the wall occurred, but the neointimal cellular lining of the prosthesis was minimal, suggesting that the fibrilar length allowed the wall to be sealed without decreasing the patency rate.     

Stromal vascular fraction combined with silicone rubber chamber improves sciatic nerve regeneration in diabetes

Purpose: To study the effects of transplantation of characterized uncultured stromal vascular fraction (SVF) on sciatic nerve regeneration. Methods: A 10-mm sciatic nerve defect was bridged using a silicone conduit filled with SVF. In control group, silicone conduit was filled with phosphate-buffered saline alone. In sham-operated group, the sciatic nerve was only exposed and manipulated. The regenerated nerve fibers were studied 8 and 12 weeks after surgery. Results: Behavioral and functional studies confirmed faster recovery of regenerated axons in SVF transplanted animals than in control group (p < 0.05). Gastrocnemius muscle mass in SVF transplanted animal was found to be significantly more than that in control group. Morphometric indices of the regenerated fibers showed the number and diameter of the myelinated fibers to be significantly higher in SVF transplanted animals than in control group. In immunohistochemistry, the location of reactions to S-100 in SVF transplanted animals was clearly more positive than that in control group. Conclusion: SVF transplantation combined with silicone conduit could be considered as a readily accessible source of stromal cells that improves functional recovery of sciatic nerve. It may have clinical implications for the surgical management of acute diabetic patients after facial nerve transection.     

A two year study of the performance of a small diameter polyurethane (Biomer) arterial prosthesis

The performance of a new compliant microfibrous polyetherurethane urea (Biomer) synthetic artery of our design has been studied in a series of 26 consecutive implants as carotid artery replacements in dogs. A 4 cm length of carotid artery was excised and replaced by a similar length of the synthetic artery. All implants were performed by the same surgeon (LdeC). Twelve interrupted sutures of 6/0 "Prolene" were used to fashion both end-to-end anastomoses. Assessments of patency of the grafts was made using fortnightly Toshiba B scan ultrasound with linked Doppler shift waveform analysis. Twenty-six grafts were implanted. Seventeen grafts have remained patent for periods in excess of 24 months. Five failed acutely (within 2 weeks), 4 failed between the 59th and 201st day. Sixteen of those grafts that remained patent for more than 24 months have been removed for histopathological examination, which has demonstrated a limited extension of a new intima on to the inner surface of the grafts. The new intima is firmly attached and shows no sign of pseudo-intimal hyperplasia. The inner surface, uncovered by neointima, nevertheless, has extensive endothelial cover. Of practical importance are the excellent handling qualities of the graft. It cuts cleanly without fraying and a stitch placed 1 mm from the cut end of the graft will hold securely. There is no needle hole bleeding. The graft has both axial and circumferential compliance similar to that of the natural artery it replaces.(ABSTRACT TRUNCATED AT 250 WORDS)     

Early results of a reinforced biosynthetic ovine collagen vascular prosthesis for small arterial reconstruction

The efficacy of a reinforced biosynthetic ovine collagen (RBOC) vascular prosthesis developed for small arterial reconstruction was assessed by examining 30 grafts in 29 patients with arteriosclerosis obliterans. The operative procedures performed were femorofemoral bypass in 2 patients, above-knee femoropopliteal bypass in 28 patients, and below-knee femoropopliteal bypass in 1 patient. Femoropopliteal bypass was simultaneously performed in two patients undergoing femorofemoral bypass using one or two grafts. The indications for surgery were intermittent claudication in 27 patients and to salvage the limb in 2 patients. The longest follow-up period was 49 months, and there were six graft failures, occurring 1, 1, 9, 17, 17, and 23 months after implantation, respectively; caused by compression of the graft from outside in two, infection in one, anastomotic intimal hyperplasia in one, and unknown factors in two. Thus, the primary cumulative patency rate for above-knee femoropopliteal bypass at 3 years was 83.7%, and the secondary patency rate was 91.2%. No aneurysmal change was observed. Moreover, the RBOC was able to be used without preclotting, and its handling and suturing characteristics were satisfactory. Our findings suggest that this vascular prosthesis may be an acceptable alternative for above-knee femoropopliteal bypass.