Expanded Polytetrafluoroethylene Prosthesis Research Articles

Three-Dimensional Morphological Study on the Effectiveness of Expanded Polytetrafluoroethylene Prosthesis in the Paranasal Augmentation.

The paranasal depression is a common facial feature of Oriental populations. One of the most wildly used method to improve it was paranasal augmentation using expanded polytetrafluoroethylene (ePTFE). The effectiveness of it should be tested by three-dimensional morphological measurements. Patients who underwent paranasal augmentation using ePTFE between January 2017 and December 2022 were recruited in the study. The preoperative and postoperative clinical variables and three-dimensional measurement of patients were also collected. The satisfaction outcome were assessed. By establishing a coordinate system based on the Frankfurt plane, 16 landmarks including nasal alar crest, subnasal point, upper lip, pogonion, glabella, sub-cheek, orbitale, tragion in left and right side of faces were marked. Five segments, 4 ratios, and 3 angles were measured based on it. The significant increase of segments, ratios, and angles indicated that paranasal augmentation could increase the protrusion of paranasal area, both in absolute value and relative proportion. The significant decrease of other data indicated that the protrusion difference between paranasal base and upper lip, forehead, and chin, respectively, were shortened after surgery. The average size of implant was 6.54 ± 1.02mm, and the average increase of paranasal height was 4.38 ± 1.04mm postoperatively. This indicates that two-thirds of its height will ultimately be reflected effectively in the sagittal elevation of the paranasal base. Paranasal augmentation using ePTFE could effectively increase paranasal height and improve subunits relationships, and the ePTFE prosthesis should be designed and carve considering the 1/3 loss of height after implantation. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Infected Abdominal Aortic Aneurysms Treated with Extra-anatomic Prosthesis Bypass in the Retroperitoneum

Infected abdominal aortic aneurysms (iAAAs) are rare but life-threatening diseases. The purpose of the present study was to report our experience of extra-anatomic prosthesis bypass in the retroperitoneum as a treatment for iAAAs. Data of 8 consecutive patients diagnosed with iAAAs and treated by an extra-anatomic prosthesis bypass in the retroperitoneum were retrospectively collected. Operative details were as follows: one side of the retroperitoneal space was selected to build a track, and a bifurcated expanded polytetrafluoroethylene prosthesis was placed through the track. The proximal end of the prosthesis was sutured with the normal segment of abdominal aorta proximal to the infected aneurysm by end-to-end anostomosis. The 2 distal ends of the prosthesis were, respectively, sutured with the external iliac artery distal to the aneurysm. The anastomoses were then consolidated with the nearby connective tissue. After the closure of the retroperitoneum, the infected aneurysm was incised, and the infected tissue was debrided. Drainage tubes were placed in the aneurysm sac, which was packed with an omentum flap. All patients received perioperative antibiotic therapy for a period of time. All 8 patients were regularly followed up by outpatient observation. Eight patients with iAAAs underwent an extra-anatomic prosthesis bypass in the retroperitoneum and debridement of the infected aneurysm. An emergency operation was performed for 1 patient who underwent concomitant gastrointestinal procedures for aortoduodenal fistula. All 8 patients were definitively diagnosed by one or more sequential computed tomography scans combined with other methods. The blood or tissue cultures of all cases were positive in the perioperative period, with Salmonella (5 cases) being the most common pathogens. Other pathogens included Burkholderia pseudomallei (2 cases) and Escherichia coli (1 case). All patients survived and were discharged in 4-5weeks after their operations. All patients were free from graft infection during the follow-up period. The extra-anatomic prosthesis bypass in the retroperitoneum for treating iAAAs was safe and effective. Our experience with the procedure may provide a new approach for the treatment of this disease.

Resolución quirúrgica de enfermedad renovascular: un reporte de 10 casos

Introduction and objectivesSurgical treatment of renal vascular pathology is still having favorable results when it is performed in selected patients. The aim of this study is to analyze 10 cases with renovascular disease and its short and long-term outcomes. MethodsWe conducted a retrospective study with all the patients who had a diagnosis of aneurysm and/or stenosis of the renal arteries (RA) that required surgical treatment from June 2000 to July 2015 in our centre. ResultsFrom 10 patients, 90% were female, mean age 52±17 years. Ninety percent had hypertension, 2 patients had history of chronic renal failure, and one case was admitted with acute renal failure. Five patients had muscular fibrodysplasia. Thirty percent were previously treated with stents in the RA, and another one had a history of an aortic-renal bypass. In 6 cases surgery was performed using the saphenous vein as a graft for the bypass, and in one, the bypass was made with an expanded polytetrafluoroethylene prosthesis. One patient had a RA plasty, and in 2 cases a nephrectomy was performed in order to resolve the pathology, and after that, the kidney was autotransplanted. Hospital stay was 9.2±3.3 days and mean follow up time was 5.8±4.5 years. There were no deaths during or after surgery. ConclusionsEven though endovascular treatment for renal artery disease is indicated in some scenarios, surgical treatment is still an option in selected patients with excellent results.

Traumatic pseudoaneurysm with 30 years of evolution

Upper limb pseudoaneurysms have a low prevalence (under 2%) due to a lower number of iatrogenic complications caused by a lower frequency of procedures and better vessel compressibility at this level. The limited distension in the neuromuscular sheath and the disposition of fascial and muscular layers cause the hemorrhage to spread and predispose to a compartment syndrome with early neurological involvement. The potential treatments are conventional surgery, implantation of endovascular devices, and ultrasound-guided thrombin injection. The factors taken into account when deciding treatment are the anatomy, the presence of compressive signs on a nerve vascular level, and the presence of signs of infection. The image shows a 49-year-old male patient, with hypertension as a cardiovascular risk factor, who suffered a sharp traumatism in the axillary area of his upper left limb 30 years ago. This trauma caused a humeral head fracture that required surgery via a lateral approach, in order to remove the metal piece and fix the humerus. This was done without conducting an examination of the vascular bundle, as the hemorrhage was stopped by applying pressure. The patient visited the doctor due to paresthesia, edema, and a heavy feeling that prevented him from resting at night during the last month. Upon examination, the patient showed pulses at all levels, and a pulsatile mass with thrill could be observed on the left axillary area. The arteriography and computed tomography angiography scan conducted (Cover; A and B) show a humeral arteriovenous fistula (arrows in Fig A and Fig B) associated with a 6-cm 11-cm-sized axillary sac pseudoaneurysm and retrograde venous distention. Given the compressive signs and the presence of an arteriovenous fistula, thrombin injection was ruled out. At the same time, the inconsistency of proximal and distal diameters did not allow the placement of a coated stent. It was decided to conduct conventional surgery (C) through a direct axillary approach. Resection of the pseudoaneurysm was conducted, with fistula ligation and humerus-humeral bypass. A 6-mm to 4-mm expanded polytetrafluoroethylene prosthesis was used, as it was a very short graft, and it allowed a better consistency in proximal and distal diameter.

Methods for Carving Expanded Polytetrafluoroethylene Prostheses in Augmentation Rhinoplasty and Their Impact on Nose Shape

Sir:FigureProsthesis shape will directly impact postoperative nose aesthetics in augmentation rhinoplasty. This article reports methods of carving the prosthesis and their impact on nose shape. The commercial name of the expanded polytetrafluoroethylene used in our hospital operations was Tisuthes (Shanghai Suokang Medical Implants, Shanghai, People's Republic of China).1 Its dimensions were 70 × 15 × 8 mm. Low-lying noses were divided into three types: low nasion (type A), low nasal bridge (type B), and low nasal bridge and tip (type C) (Fig. 1, above). Prostheses were carved into a short willow shape, a long willow shape, or an L shape, respectively.Fig. 1: Three types of low-lying noses (low nasion, low nasal bridge, and low nasal bridge and tip) and the carving procedures to create the short willow-shaped, long willow-shaped, and L-shaped prostheses.For length (Fig. 1, second row), the starting point, A, was the horizontal line 3 to 4 mm above the midline between the eyebrows and eyes. The ending point, B, was the tangent point of the prosthesis and nasion skin for type A and B. For type C, it marked the junction of the facial vertical line of the columella-lobular angle and the prosthesis. A triangular section was cut from both sides of the prosthesis at point B to divide it into a long segment (used on the nasal bridge) and a short segment (used for the columella, approximately 10 mm). The width at the junction of the long and short segments was 3 to 5 mm. For the ventral surface (Fig. 1, third row), for type A, a triangular section was obliquely cut from both the cephalic end and nasal end of the ventral surface of the prosthesis to maximize the attachment between the ventral surface of the prosthesis and the nasal bridge. Type B was approached the same as type A. If there was a small bump on the nasal bridge, a hole was made at the corresponding spot on the ventral surface of the prosthesis. For type C, the long segment is the same as type B. The short segment of the prosthesis was obliquely trimmed from point B and varied from 1 to 3 mm thick beyond that point. For width (Fig. 1, fourth row), for types A and B, a wedge was cut from both sides of the prosthesis to achieve the desired width, which was approximately 12 mm for male patients and 10 mm for female patients. The width at point B was approximately 5 mm. For type C, the long segment is the same as for type B. The short segment was gradually tapered to 1 mm or to have an angle near its tip. For the dorsal surface (Fig. 1, fifth row), for type A, a 135- to 140-degree angle was carved at point A of the prosthesis dorsal surface, which was trimmed to a desired thickness of no more than 3 mm for type A. For type B, the thickness is usually no more than 8 mm for male patients and 6 mm for female patients. For type C, the long segment is the same as for type B. The prosthesis was cut open transversely at the superficial layer of the junction of the long and short segments. The short segment was then folded ventrally to form an L-shaped prosthesis. The impact of each factor on nose shape is summarized in Table 1.1–4Table 1: The Impact of Length, Width, Dorsal Surface, and Ventral Surface on Nose ShapeXudong Zhang, M.D. Qinjian Peng, M.D. Yongcheng Xu, M.D. Department of Cosmetic Surgery, Beijing Huangsi Aesthetical Surgery Hospital, Beijing, People's Republic of China DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.

Chest Wall Reconstruction using Gore-Tex^|^#174; Dual Mesh

This study aimed to evaluate the clinical outcomes of chest wall reconstruction using a relatively new expanded polytetrafluoroethylene prosthesis Gore-Tex(®) dual mesh. We reviewed charts of 11 patients who underwent bony chest wall resection from April 2006 to January 2011. Six patients underwent three ribs resection, three patients underwent two ribs resection, and the other two patients underwent sternal resection. Of six patients after three ribs resection, three underwent reconstruction using 2 mm Gore-Tex(®) dual mesh, one using Gore-Tex(®), one using Bard composite E/X, and the remaining one used no prosthesis. Three patients who underwent two ribs resection underwent no chest wall reconstruction using prosthesis. Two patients who underwent sternal resection underwent chest wall reconstruction using dual mesh with or without a vascularized musculocutaneous pedicle flap. Immediate postoperative extubation was performed in all patients, except one who was extubated the following day. No postoperative deaths or cases with paradoxical respiration occurred. Chest wall reconstruction using Gore-Tex(®) dual mesh demonstrated acceptable durability.

Expanded polytetrafluoroethylene in canine bile duct injury: a critical analysis

Analyze the morphological and structural outcomes of a patch of expanded polytetrafluoroethylene in the treatment of an iatrogenic injury of the common bile duct. In Group 1 (Sham), 7 dogs underwent 3 laparotomies with intervals of 30 days between them. In Group 2, 10 dogs underwent transient common bile duct obstruction. After 30 days, this biliary occlusion was undone and a patch of expanded polytetrafluoroethylene replaced a fragment removed from the duct's wall. Thirty days after this last surgery, cholangiographic assessment of prosthesis patency and macro and microscopic evaluation of the biliary tract were performed. Daily clinical inspection completed the study outcomes. The Wilcoxon non-parametric test was used for statistical analysis. In all dogs enlargement of the biliary tree diameter was observed 30 and 60 days after the first surgical procedure. Partial adhesion of the patch to the common bile duct as a free luminal foreign body was found in 6 dogs. The prosthesis was completely integrated to surrounding tissue in the remaining four. Although a feasible option for the treatment of biliary duct iatrogenic lesions, the expanded polytetrafluoroethylene prosthesis must be used with caution considering the potential risks for complications.

Long-term results of chest wall reconstruction with DualMesh

The aim of this study was to evaluate the clinical outcomes of chest wall reconstruction using a new, expanded polytetrafluoroethylene prosthesis, 'DualMesh'. Between December 2005 and March 2010, chest wall reconstruction using 2-mm DualMesh was performed in 11 patients. The indication for resection was primary lung cancer in six patients, malignant mesothelioma in one patient, recurrent lung cancer in one patient, recurrent invasive thymoma in one patient, postirradiated osteomyelitis in one patient, and chondro-hamartoma in one patient. The mean observation period was 23 months, and four cases were observed for more than three years. There were no operative deaths and no wound infections. There were two postoperative complications: prolonged air leakage occurred in a patient with pulmonary emphysema who underwent right lower lobectomy, and slight paradoxical respiration occurred in the patient who underwent resection of the entire sternal body for osteomyelitis. Follow-up chest computed tomography was performed routinely. No dehiscence occurred in any cases. Chest wall reconstruction using DualMesh demonstrated acceptable durability and biocompatibility, even after long-term follow-up. DualMesh has the potential to become an ideal prosthesis for the bony chest wall as an alternative to conventional polytetrafluoroethylene or polypropylene grafts.

A Novel Cross‐linked Poly(vinyl alcohol) (PVA) for Vascular Grafts

AbstractPoly(vinyl alcohol) (PVA) is a water‐soluble synthetic polymer with excellent film‐forming, emulsifying, and adhesive properties. The aim of this study is to design a simple process for PVA cross‐linking with sodium trimetaphosphate to form membrane devices suitable for biomedical applications. This procedure requires no organic solvent, nor melting process to obtain films with high mechanical strength. Fabrication of a small diameter tube from a PVA film is easy with a single wrapping step around a Teflon rod. Dynamic mechanical analysis demonstrated that, upon removal of the applied stress, the PVA film with a Young's modulus of 2 × 105 kPa returns to its original size and shape. The wall thickness of PVA tubes is 344 ± 13 µm (n = 12), which is close to the wall thickness of a human artery (350–710 µm). Suture retention of a PVA tube is excellent (140 ± 11 g), close to that of human vessels. The burst pressure of PVA tubes is found to be 507 ± 25 mm Hg, more than three times higher than the human healthy systolic arterial pressure. Under arterial pressure, there was no leakage even after needle puncture, contrary to clinical vascular expanded polytetrafluoroethylene prostheses. Finally, PVA tubes of 2 mm in diameter are used to replace a segment of an infrarenal aorta in rats. For at least one week, no mechanical nor thrombotic complications are noticed even in the absence of anticoagulant or antiplatelet treatment. Graft patency is also evidenced with non‐invasive imaging techniques. As a conclusion, this novel cross‐linking method confers to poly(vinyl alcohol) particular mechanical properties such as compliance, elasticity and resistance to mechanical stress, compatible with the circulatory blood flow.

Recurrences after laparoscopic repair of ventral and incisional hernia: lessons learned from 505 repairs

All hernia recurrences in a series of 505 patients who underwent laparoscopic repair of a ventral hernia (n=291) or incisional hernia (n=214) were analyzed to identify factors responsible for the recurrence. In all laparoscopic repairs, an expanded polytetrafluoroethylene prosthesis overlapping the hernia margins by >or=3 cm was fixed with a double ring of tacks alone (n=206) or with tacks as well as sutures (n=299). During the mean follow-up time of 31.3 +/- 18.4 months, nine patients (1.8%) had a recurrence, eight of which were repaired laparoscopically. Operative reports and videotapes of all initial repairs and repairs of recurrences were analyzed. All recurrences followed an incisional hernia repair (p<0.001). Five recurrences developed after mesh fixation with both tacks and sutures and four after mesh fixation with tacks alone (p=1.0). All recurrences were at the site of the apparently sufficient original incision scar: in eight patients, the recurrent hernia was attached to the mesh; in one, it developed in another part of the scar. All initial repairs had been performed without technical errors. Upon repair of the recurrences, a new, larger mesh was placed over the entire incision, not just the hernia. There were no re-recurrences during follow-up (mean 19.8+/-10.3 months). Recurrence after incisional hernia repair appears to be due primarily to disregard for the principle that the whole incision--not just the hernia--must be repaired. Our experience supports the idea that the entire incision has a potential for hernia development. Insufficient coverage of the incision scar is a risk factor for recurrence after laparoscopic repair of ventral and incisional hernia.

Role of fibrin glue in the prevention of peritoneal adhesions in ventral hernia repair

The aim of this study was to investigate the effects of fibrin glue on the prevention of postoperative peritoneal adhesion to prosthetic materials used in ventral hernia repair. Ten pigs were included in this study. The abdomens of the animals were opened by means of a median subumbilical laparotomy to place four prostheses that were cut into square pieces of 4 x 4 cm. The two prostheses in the most cephalic position were polypropylene meshes, and the other two prostheses in a more caudal position were expanded polytetrafluoroethylene prostheses (Dualmesh Plus Corduroy). The prostheses on the right side of each animal were previously impregnated with fibrin glue. After 5 weeks, the animals were reoperated on to assess the quantity and quality (consistency) of the adhesions. There were fewer intraperitoneal adhesions and they were more labile in the case of prostheses impregnated with fibrin glue. Moreover, we also observed that in many of the animals the polypropylene mesh did not show any adhesions, although polypropylene has been considered to be a typical adhesion producing material. Fibrin glue reduces both the quantity and consistency of adhesions, even in the case of polypropylene meshes.

Venous reconstructions in lower limbs associated with resection of malignancies

Patients with tumors in the limbs who undergo surgical treatment may have involvement of major vessels. Major arteries are always reconstructed for limb salvage. Major veins may be reconstructed to avoid the onset of venous hypertension signs and symptoms. The objective of this study was to analyze the results from surgical treatment of a sample of patients who underwent lower limb venous reconstructions associated with the resection of malignant tumors. Follow-up was performed of 17 patients with malignant tumors involving major vessels in the lower limbs. The median length of follow-up was 22 months. Venous reconstruction concomitant to arterial reconstruction was performed in 15 patients, and an isolated venous reconstruction was performed in 2 patients. The venous substitutes used were the contralateral long saphenous vein (n = 12), expanded polytetrafluoroethylene prosthesis (n = 3), and Dacron prosthesis (n = 2). Vascular complications occurred in seven patients: three occlusions of the venous graft, edema in seven patients, and one rupture of the arterial graft. The primary 2- and 5-year patency rates of venous reconstructions were 79.3% and 79.3%, respectively. Nonvascular complications occurred in six patients: neurological deficit (n = 3), partial necrosis of the flap (n = 2), wound infection (n = 1), hematoma (n = 1), and enteric fistula (n = 1). Eight patients were still alive and disease free, although one of them underwent above-knee amputation as a result of local disease recurrence. One patient experienced regional disease recurrence and is undergoing chemotherapy. Eight patients died due to pulmonary metastases. The 2- and 5-year overall survival rates were 58.6% and 42.4%, respectively. The 2- and 5-year thrombosis-free survival rates were 51.9% and 35.2%, respectively. Lower limb venous reconstructions associated with tumor resection in this study gave good functional results, although the prognosis for these patients had been unfavorable. The saphenous vein is a suitable substitute.

Functional properties of fresh and cryopreserved carotid and femoral arteries, and of venous and synthetic grafts: comparison with arteries from normotensive and hypertensive patients

The ideal arterial graft must share identical functional properties with the host artery. Surgical reconstruction of the common carotid artery (CA) is performed in several clinical situations, using expanded polytetrafluoroethylene prosthesis (ePTFE) or saphenous vein (SV) grafts. At date there is interest in obtaining an arterial graft that improves the results of that nowadays available. The use of a fresh or cryopreserved/defrosted artery appears as an interesting alternative. However, if the fresh and cryopreserved/defrosted arteries allow an adequate viscoelastic and functional matching with the host arteries needs to be established. The aims were to compare the viscoelastic and functional performance of: (1) conduits used in CA reconstruction (SV and ePTFE) with those of the fresh and cryopreserved/ defrosted CA and femoral arteries (FA), and (2) normotensive and hypertensive patients' arteries with those of the arterial substitutes in vitro analyzed. Pressure, diameter and wall thickness of the CA were recorded in 15 normotensive and 15 hypertensive patients (in vivo studies), and in SV, fresh and cryopreserved/defrosted CA and FA (obtained from 15 donors), and ePTFE segments (in vitro studies). From stress-strain relationship we calculated elastic and viscous modulus, and the characteristic impedance. The local buffer and conduit functions were quantified as the viscous/elastic quotient and the inverse of the characteristic impedance. Fresh and cryopreserved/defrosted CA and FA were more alike, both in viscoelastic and functional levels, respect to normotensive and hypertensive patients' arteries, than the ePTFE and SV grafts. CA and FA cryografts could be considered an important alternative for carotid reconstruction.

Results of limb-sparing surgery with vascular replacement for soft tissue sarcoma in the lower extremity

To evaluate limb-salvage surgery with vascular resection for lower extremity soft tissue sarcomas (STS) in adult patients and to classify blood vessel involvement. Subjects were consecutive patients (median age, 56 years) who underwent vascular replacement during surgery of STS in the lower limb between January 1988 and December 2003. Blood vessel involvement by STS was classified as follows: type I, artery and vein; type II, artery only; type III, vein only; and type IV, neither artery nor vein (excluded from the analysis). Patient data were prospectively gathered in a computerized database. Twenty-one (9.9%) of 213 patients underwent vascular resections for lower limb STS. Besides 17 type I tumors (81.0%), 3 (14.3%) type II and 1 (4.7%) type III STS were diagnosed. Arterial reconstruction was performed for all type I and II tumors. Venous replacement in type I and III tumors was performed in 66.7% of patients. Autologous vein (n = 8) and synthetic (Dacron and expanded polytetrafluoroethylene; n = 12) bypasses were used with comparable frequency for arterial repair, whereas expanded polytetrafluoroethylene prostheses were implanted in veins. Morbidity was 57.2% (hematoma, thrombosis, and infection), and mortality was 5% (embolism). At a median follow-up of 34 months, the primary and secondary patency rates of arterial (venous) reconstructions were 58.3% (54.9%) and 78.3% (54.9%). Limb salvage was achieved in 94.1% of all cases. The 5-year local control rate and survival rate were 80.4% and 52%, respectively. We observed a 5-year metastasis-free survival rate of 37.7% and found vessel infiltration and higher tumor grade (low-grade vs intermediate grade and high grade tumors) to be negative prognostic factors at univariate and multivariate analysis. Long-term bypass patency rates, the high percentage of limb salvage, and the oncologic outcome underline the efficacy of en bloc resection of STS involving major vessels in the lower limb. Disease-specific morbidity must be anticipated. The classification of vascular involvement (type I to IV) is useful for surgical management.

Vascular Reconstruction in Limbs Associated with Resection of Tumors

Patients with tumors in limbs who undergo surgical treatment may present involvement of major vessels. The artery must be reconstructed for limb salvage and the vein may be reconstructed to avoid the onset of venous hypertension. The objective of this study was to analyze the results from surgical treatment of tumors associated with vascular reconstruction in limbs. A prospective follow-up was made of 17 patients with tumors involving major vessels in limbs who underwent vascular reconstruction. Arterial and venous reconstructions were performed in nine patients, arterial reconstruction was performed in six, and venous reconstruction in two patients. The vascular substitutes used were greater saphenous vein (19), expanded polytetrafluoroethylene prosthesis (5), and Dacron prosthesis (2). Vascular complications occurred in seven patients: one arterial graft rupture, three venous graft occlusions, and lymphedema in five patients. The following nonvascular complications occurred in 10 patients: pulmonary metastasis (7), local recurrence (2), neurological deficit (2), infection (2), partial necrosis of the flap (1), and enteric fistula (1). Six patients with pulmonary metastasis died. One patient underwent transfemoral amputation. Major vessel reconstruction in limbs associated with resection of neoplasms is a safe procedure. Venous revascularization should be performed using an autologous substitute.

Octylcyanoacrylate Tissue Adhesive as an Alternative to Mechanical Fixation of Expanded Polytetrafluoroethylene Prosthesis

In minimally invasive incisional hernia repair positioning and fixation of the expanded polytetrafluoroethylene (ePTFE) mesh prosthesis on the deep surface of the abdominal wall may be facilitated using tissue adhesives. Octylcyanoacrylate (OCTYL), a new adhesive, forms a strong flexible bond with antimicrobial properties. In a rabbit model for incisional hernia we investigated characteristics of the bond created by OCTYL between ePTFE and abdominal wall musculature. We studied initial bond strength and the postoperative host response to the adhesive over a 6-week period. We compared sutured, stapled, and glued mesh prostheses and examined the tissue-prosthesis interface. The ePTFE mesh was fixed successfully to the abdominal wall with OCTYL and remained tightly attached at 6 weeks. Prostheses fixed with OCTYL and spiral tacks induced few intra-abdominal adhesions compared with sutured mesh. All prostheses were completely reperitonealized at 2 weeks. The force required to displace mesh fixed with sutures and staples was greater than mesh fixed with OCTYL. Analysis of the ePTFE/tissue interface by light and scanning electron microscopy showed host cellular migration into the interstices of the mesh with fixation by tacks and suture, whereas an inflammatory infiltrate was seen on the muscular surface with OCTYL fixation of the mesh.

An experimental model for the prevention of postanastomotic tracheal stenosis

Objective: The aim of the current study is to determine the efficiency of an external prosthesis made of expanded polytetrafluoroethylene reinforced with a continuous silicone spiral to prevent postanastomotic stenosis after surgical correction of extensive tracheal defects in rabbits. Methods: Forty-five rabbits were used, divided into three groups of 15 animals each. Group A was the control group. Group B animals underwent resection of six-ring segments of the cervical trachea and primary anastomosis. The procedure used in group C was similar to that used in group B, but the tracheal anastomosis was supported by an external expanded polytetrafluoroethylene prosthesis. Results: Direct anastomosis after resection of six tracheal rings caused anastomotic stenosis in 100% of the animals. We did not observe tracheal stenosis in any rabbit when we applied an expanded polytetrafluoroethylene tube as an external stent for the tracheotracheal suture. Conclusion: We conclude that an external stent can be used to prevent tracheal stenosis resulting from the resection of six cervical tracheal rings in rabbits(J Thorac Cardiovasc Surg 1997;114:76-83)

Clinical in vitro endothelialization of femoropopliteal bypass grafts: An actuarial follow-up over three years

The creation of an endothelial coverage on prosthetic vascular surfaces may improve the performance of synthetic small diameter vascular grafts. In vitro lining with cultured autologous endothelial cells offers a confluent endothelium at the time of implantation. Between June 1989 and December 1991, 49 patients who had no saphenous vein available entered the study. Indication for operation was disabling claudication in 37 patients and critical ischemia in 12 patients. With a random 1:2 assignment, 33 patients were admitted to the endothelialized group and 16 control patients received an untreated polytetrafluoroethylene prosthesis. Cultured autologous endothelial cells from the external jugular vein were confluently lined onto polytetrafluoroethylene grafts precoated with fibrinolytically inhibited fibrin glue. The follow-up was based on angiography, platelet labeling studies with indium 111-labeled oxine, assessment of the ankle-brachial index, and duplex sonography. First-passage mass cultures of 16 million endothelial cells-required for the confluent lining of a 70 cm long 6 mm graft-were reached 25.1 +/- 11.2 days after vein excision. Growth failure occurred in 27.3%. After 32 months, the actuarial patency was 84.7% for endothelialized grafts and 55.4% for control grafts (p < 0.041 by Breslow test; p < 0.068 by Mantel-Cox test). The ankle-brachial index was continually diverging, reaching significantly lower values in the control group at 24 months (0.98 +/- 0.14 in the endothelialized group versus 0.70 +/- 0.12 in the control; p < 0.0023). The uptake of indium 111-labeled platelets--measured at 9 days, 3 months, 6 months, and 12 months--was significantly lower in the endothelialized group during the entire observation period.

Expanded polytetrafluoroethylene arterial prostheses in humans: histopathological study of 298 surgically excised grafts

The expanded polytetrafluoroethylene vascular prosthesis is considered to be the best synthetic alternative for peripheral arterial reconstruction. Most studies on the healing characteristics of expanded polytetrafluoroethylene prostheses have been carried out on animals, and very few data are available on prostheses implanted in humans long term. We implanted 298 expanded polytetrafluoroethylene grafts as arterial substitutes in humans. The mean duration of implantation was 523 d and the grafts were implanted mainly for infrainguinal or axillofemoral bypass. The cellular and collagen infiltration of the microporous expanded polytetrafluoroethylene structure was generally poor. Infiltration occurred mainly in the external region of the prosthetic wall and increased with the duration of implantation. The external reinforcement was not a major factor in limiting tissue infiltration. The luminal surfaces were covered with a thin, irregular layer of organized fibrin, interspersed with exposed expanded polytetrafluoroethylene areas. Mineral deposits were observed in five cases. Despite poor healing, the clinical performance of expanded polytetrafluoroethylene vascular prostheses is relatively good. Since the chief advantage of this material is good mechanical stability in vivo, any modifications of the graft to improve healing characteristics or thrombogenic properties should not be made at the expense of stability in vivo.

In vivo Patency of Endothelial Cell‐Lined Expanded Polytetrafluoroethylene Prostheses in an Ovine Model

The performance of small-diameter vascular prostheses may be improved by implantation of grafts lined with endothelial cells. Expanded polytetrafluoroethylene (ePTFE) prostheses (4 mm x 40 mm) were coated with fibronectin (20 micrograms/ml), seeded with endothelial cells, and cultured for 48 h to produce a confluent, autologous endothelial cell lining. They were implanted as carotid interposition grafts in sheep. Seeded ePTFE grafts were compared with nonseeded ePTFE grafts and autologous carotid artery grafts. No anticoagulant or antiplatelet therapy was administered, making this a stringent test model for the thromboresistance of a small-diameter prosthesis. After 13 weeks the patencies of seeded, nonseeded, and autologous artery grafts were 16% (1/6), 0% (0/6), and 100% (6/6), respectively. The one seeded graft that was patent was fully lined with endothelial cells and showed no stenosis. The remaining five seeded grafts were occluded by fibrous tissue and displayed substantial spindle cell hyperplasia. There was no apparent difference between the autologous artery grafts and normal arterial tissue, and the anastomoses showed no stenosis. The ovine model provides a conservative test of prosthesis survival and may be useful for study of graft failure.