New technique for decompressive duraplasty using expanded polytetrafluoroethylene dura substitute--technical note

A new technique for decompressive craniectomy with duraplasty was developed for cases in which brain swelling was present at dural closure. Expanded polytetrafluoroethylene (ePTFE) membrane is placed under the dura, covering the brain surface, without the use of sutures. The dura is then loosely sutured. The procedure was used in 13 patients. No leakage of cerebrospinal fluid into the epidural space or signs of infection were observed. Sutureless insertion of an ePTFE membrane at external decompression may increase the ease of duraplasty, decrease operating time, and avoid injury to the brain resulting from suturing the dura. The technique might be especially useful in emergency cases.     

膨化聚四氟乙烯补片术后11年迟发性深部感染一例

正患者女性,62岁,主因"左侧腹股沟区异常分泌物1月余"入院。患者2006年因"左侧腹股沟疝"在当地医院使用膨化聚四氟乙烯补片(美国GORE公司)行左侧腹股沟疝无张力修补术(Lichtenstein术式),术后切口Ⅰ/甲愈合,术后至今无疝复发。2017年5月,患者无明显诱因发现左腹股沟区手术瘢痕处持续流少量黄色脓液,于当地医院予以抗感染、换药等对症治疗,未见好转。随后于四川大学华西     

Duraplasty in the posterior fossa using a boat-shaped sheet of expanded polytetrafluoroethylene

Application of sutures between expanded polytetrafluoroethylene (ePTFE) dural substitutes and the dura mater is often frustrating in posterior fossa surgery because of the difficulty in holding the elastic graft in a deep and narrow field. To resolve this problem, we have developed a boat-shaped graft made from a triangular ePTFE sheet by pinching each angle using a suture. Formation of standing edges of the sheet facilitates holding of the flaps for secure and more rapid suturing than the conventional approach using a flat sheet.     

Hernia repair with expanded polytetrafluoroethylene.

Prostheses of expanded polytetrafluoroethylene (e-PTFE) were used to repair 89 abdominal wall defects in which primary closure would produce undue tension on tissue. Over a 52-month period (median follow-up: 24 months), we observed three wound infections, one in a clean wound, and four hernia recurrences. No other complications were noted. Twenty-one e-PTFE grafts were placed directly over intraperitoneal viscera without clinical evidence of adhesions leading to intestinal obstruction. In grafts inspected postoperatively, no apparent evidence of fatigue or fragmentation was observed. Histologic findings concurred with experimental data obtained during animal trials revealing the creation of a new mesothelial lining. These results encourage the use of e-PTFE prostheses for the repair of abdominal wall hernias, particularly when the parietal peritoneum is absent.     

膨体聚四氟乙烯缝线替换心瓣膜腱索

目的：验证膨体聚四氟乙烯缝线在心脏瓣膜成形术中行腱索替换的效果。方法：１９９１年６月至１９９８年３月在心瓣膜成形术中采用膨体聚四氟乙烯缝线进行人工腱索替换２３例：替换二尖瓣腱索２８支,三尖瓣腱索１支。结果：病人人武部康复出院。其中１７例随访２￣７８个月,平均１８．５个月。彩色Ｂ超复查显示瓣膜关闭不全完全矫正者６例,仍残存极为以并关闭不全者３例,轻并关闭不全７例,术后仍有中并反流１例,系人工腱索过短     

Tissue-engineered cartilage composite with expanded polytetrafluoroethylene membrane

The authors report a new approach using expanded polytetrafluoroethylene (ePTFE) membrane as pseudoperichondrium to support engineered cartilage. Swine auricular chondrocytes were isolated and mixed with fibrin glue to achieve a final concentration of 40 x 10(6) cells per milliliter. The fibrin glue-cell suspension was assembled with ePTFE and the constructs were implanted into the dorsal subcutaneous pockets of nude mice for 12 weeks. Two experimental groups were prepared in this study: (1) ePTFE placed in the central part of the specimen in group 1 and (2) ePTFE placed on the outside surfaces in group 2. All specimens were subjected to histological and gross mechanical evaluation. Histological results showed neocartilage formation in both groups. The integration between neocartilage and ePTFE forms a tight bond. Gross mechanical testing revealed that the flexibility of specimens in group 2 were similar to that of native cartilage with intact perichondrium, whereas the flexibility of specimens in group 1 were poor. From these results the authors conclude that it is possible to produce a tissue-engineered cartilage framework using ePTFE as a support material to simulate the perichondrium.     

Preliminary experience with expanded polytetrafluoroethylene grafts.

This early clinical experience of members of the New England Society for Vascular Surgery with expanded polytetrafluoroethylene (PTFE) grafts was evaluated. Questionnaires were distributed to 52 active members of the Society and 32 answers were received. A total of 186 graft insertions were evaluated, of which 112 were positioned in the lower limb; 106 grafts were inserted for libm salvage. Patency rates for femoral-popliteal bypass grafts were determined by life-table analysis. Our results show a 6 to 9 month cumulative patency rate of 91% for PTFE grafts with a popliteal anastomosis above the knee, and a 52% patency rate for below-knee anastomosis. Two complications, aneurysmal dilatation and graft sepsis, were noted in this series. The new graft material exhibits an early patency rate higher than bovine or Dacron grafts which warrants long-term use and evaluation.     

脊柱膜与生物蛋白胶联合应用预防硬膜外粘连的实验研究

目的观察椎板切除术后联合使用脊柱膜与生物蛋白胶预防硬膜外粘连的效果,探讨从三维上预防粘连的最佳方案。方法本课题采用动物实验,运用拉丁方实验设计,分别做无植入（A组）,植入生物蛋白胶（B组）,脊柱膜（C组）,脊柱膜和生物蛋白胶（D）于兔的4个节段,术后4周对椎板切除部位进行大体观察、组织学观察及MR I检查,比较各组瘢痕形成和粘连情况。结果①A组可见大量瘢痕组织增生,以硬膜囊后方明显,粘连严重。②B组防粘连的效果差。③C组的防粘连的效果优于A组和B组,但差于D组。④D组,不但能够防止后方肌肉及疤痕组织的长入,而且可防止前方、周围硬膜及神经根的粘连。结论联合使用硬体材料脊柱膜和流体材料生物蛋白胶是防止椎板切除术后硬膜粘连的最佳方案。     

Microarterial prostheses of expanded polytetrafluoroethylene

Forty grafts of expanded polytetrafluoroethylene (PTFE) with an inside diameter of 1.5 mm were placed in the femoral arteries of rabbits. The telescoped technique was used for the anastomoses. The animals were sacrificed at intervals beginning the day after implantation. Four of the grafts lost patency and one graft had a remarkable degree of intimal hypertrophy. The remaining grafts developed thin neointimal formations and remained patent up to 7 months after implantation. The overall patency rate was 90%. Neointimization was established 35 to 90 days following surgery. The formation of neointima began at the anastomotic sites and extended into the grafts. It is concluded that PTFE prostheses can be used for grafting arteries as small as 1.0-1.2 mm in diameter, which up to now had been considered impossible.     

Modified distal splenorenal shunt with expanded polytetrafluoroethylene interposition

Two types of modified distal splenorenal shunt with expanded polytetrafluoroethylene (Gore-Tex; WL Gore & Associates Inc., Elkton, Md.) interposition were performed in 18 consecutive patients with esophageal or esophagogastric varices. There were 12 men and six women ranging in age from 32 to 76 years. The causes of portal hypertension were cirrhosis of the liver in 15 patients, chronic hepatitis in two, and idiopathic portal hypertension in one. In five patients the left gastric vein branched off from the splenic vein; bilateral gastric venous decompression was achieved by preserving the splenic vein. Porta-azygos disconnection was routinely performed by confirming repeated intraoperative direct splenoportography. The operations were elective in seven and were emergencies in five patients. Six patients underwent a prophylactic shunt; all patients had "red color signs" endoscopically, and three of them had concomitant hepatocellular carcinoma. Postoperative morbidity was minimal and there was no mortality. Shunt patency was confirmed angiographically in all patients 14 to 56 days after surgery. The varices disappeared or significantly improved in all patients. No patients had variceal bleeding postoperatively. Hepatic encephalopathy was transiently seen in one (the oldest) patient.     

Ulnar nerve reconstruction with an expanded polytetrafluoroethylene conduit.

The ulnar nerve of a 22-year-old woman was reconstructed by expanded polytetrafluoroethylene (ePTFE) conduit, 141 days after nerve transection at the distal forearm level. A 2.9 cm nerve gap was bridged by a corrugated, 3.9 cm long, 6 mm diameter ePTFE tube. At final evaluation 3 years later the patient achieved excellent motor and sensory recovery. Exploration of the tube, at that time, showed macroscopically normal nerve inside the conduit.     

Small vessel replacement with gore-tex (expanded polytetrafluoroethylene).

Conduits of expanded, fibrillated polytetrafluoroethylene (PTFE [Gore-tex]) have been evaluated as small vessel prostheses in dogs during a 6-month period. A configuration of high porosity and low density, long fibril Gore-tex was found to yield the best patency in canine arteries (femoral and carotid) and veins (femoral) as compared with more dense, less porous PTFE with shorter fibrils. Host tissue reaction showed minimal inflammation, excellent infiltration, and formation of a smooth neointima, which suggested satisfactory acceptance of the prosthesis.     

Long-term results with the above-knee popliteal expanded polytetrafluoroethylene graft

Since approximately 30% to 40% of autogenous vein bypass grafts to the femoropopliteal level may occlude within 5 years of implantation, additional vein will be required for subsequent revisions. We undertook a study to determine whether the preferential use of an above-knee expanded polytetrafluoroethylene bypass graft to save vein is an appropriate option. We reviewed our experience with 114 above-knee expanded polytetrafluoroethylene bypass reconstructions. Life-table analysis of primary and secondary graft patency was carried out by the method of Peto and statistically analyzed for the influence of clinical indication, runoff as determined by both preoperative and intraoperative completion arteriography, smoking, and diabetes. The 5-year primary patency rate of 57% for patients with claudication was comparable to contemporary randomized or retrospective series with below-knee autogenous vein for that indication, and it was superior to the patency rate for limb salvage. The status of the runoff vessels was an important determinant of outcome. The 59 limbs with good arteriographic runoff (2 to 3 vessels) had a markedly higher 5-year patency rate (70%) than the poor arteriographic runoff (0 to 1 vessels) group (30%). Continued cigarette smoking and diabetes mellitus also appeared to affect adversely primary graft patency in our hands. Our data support the use of preferential above-knee expanded polytetrafluoroethylene grafts in patients with good angiographic runoff. This approach does not appear to prejudice the limb against secondary revisionary procedures or the use of a new autogenous graft, if required.     

膨体聚四氟乙烯（ePTFE）内支撑组织工程软骨的构建实验研究

目的：探讨骨髓间充质干细胞和软骨细胞混合培养体外构建ePTFE软骨复合体的可能性。方法：实验组：分离、获取、扩增兔骨髓间充质干细胞和软骨细胞,二者按7：3比例混和,接种到以膨体聚四氟乙烯（ePTFE）为内支撑外裹聚羟基乙酸（PGA）支架上,体外培养8周后,行大体、组织学、Ⅱ型胶原免疫组织化学和生物化学检测。对照组：利用实验组支架单纯接种骨髓间充质干细胞行体外培养。结果：实验组：体外培养8周后形成形态良好的软骨样组织复合体,组织学可见成熟软骨陷窝、异染基质、Ⅱ型胶原表达阳性。对照组：无软骨形成。结论：兔骨髓间充质干细胞和软骨细胞混合培养,可以在体外构建出特定形状、结构组织学良好的ePTFE软骨复合体。     

Intermediate and early rupture of expanded polytetrafluoroethylene neochordae after mitral valve repair

Neochordae construction using an expanded polytetrafluoroethylene suture is an accepted surgical technique to correct mitral regurgitation due to mitral valve prolapse. We report two cases of intermediate and early rupture of CV-5 expanded polytetrafluoroethylene neochordae after mitral valve repair. As a result of these cases, we now use CV-3 expanded polytetrafluoroethylene for neochordae construction with no failures.     

Polyurethane vascular prostheses decreases neointimal formation compared with expanded polytetrafluoroethylene

Purpose: Synthetic grafts have been increasingly used for complex vascular reconstructions in patients with limited autologous vein availability. Materials currently in use induce increased stenosis and graft thrombosis compared with autologous vein, especially in smaller vessels. We examined whether grafts constructed of a porous biodegradation-resistant polycarbonate polyurethane (PU) exert better biocompatibility in terms of faster endothelialization and decreased chronic proliferation of intimal cells compared with expanded polytetrafluoroethylene (ePTFE). Methods: PU or ePTFE interposition grafts were implanted into the abdominal aortas of male Sprague-Dawley rats (PU, n = 37; ePTFE, n = 32). Grafts were removed at days 1, 7, 14, 28, and 56 and 6 months and were evaluated by immunohistochemical, electron microscopic, and morphometric techniques. Bromodeoxyuridine (BrdU) was injected at 1 and 24 hours before death to determine cellular proliferation. Endothelial cells and smooth muscle cells were identified with antibodies to von Willebrand factor and α-actin, respectively. Results:The luminal surface of PU grafts took 4 weeks to completely endothelialize, whereas ePTFE grafts took 24 weeks (P < .05). Neointimal cell proliferation was lower in PU grafts compared with ePTFE at 56 days (1.4 ± 0.1 versus 8.6 ± 1.5, P < .001) and at 6 months (0.15 ± 0.002 versus 3.4 ± 0.5, p < .001). Neointimal thickness at 6 months after implantation was 3.2 ± 0.8 μm for PU compared with 10.3 ± 3.1 μm for ePTFE (P < .05). Conclusion: Polycarbonate polyurethane small vascular prostheses promoted faster luminal endothelialization, induced less chronic intimal proliferation, and produced a significantly thinner neointima than ePTFE grafts. These findings suggest that aliphatic-polycarbonate urethanes may offer advantages over standard materials such as ePTFE for vascular graft construction. (J Vasc Surg 1999;29:168-76)