Comparison of 10-0 polypropylene and 10-0 nylon sutures in rat arterial anastomosis

The selection of suture materials is an important factor in further improving the results of microsurgical operations. In this study, two kinds of nonabsorbable suture materials, 10-0 polypropylene and 10-0 nylon monofilament, were compared in end-to-end anastomosis of 66 femoral arteries of adult rats. Both suture types were of identical size (70 μm needle/28 μm suture) and each artery received eight sutures. The vessels were harvested at various intervals from 2 hr to 180 days postoperatively and were evaluated by pathology, radiology, and tensile strength test. The results show that both sutures are capable of achieving excellent long-term patency (100%) of anastomosed sites. Polypropylene suture was equivalent to nylon in mechanical integrity of the anastomosis sites but was superior in handling, knotting, and biocompatibility. These physical and biological properties of polypropylene sutures may offer the benefits of diminished early and late complications at anastomosis sites and reduced operation time. Enhancement of contrast against surrounding tissue may make polypropylene a superior alternative to nylon sutures for microsurgical use. © 1993 Wiley-Liss Inc.     

Laser-assisted vasal anastomosis in the rat and man

In order to study the efficacy of laser-assisted vasal anastomosis (LAVA), a microscopic carbon dioxide surgical laser (Xanar) was utilized in the anastomoses of human vas deferens in vitro and the Sprague-Dawley rat vas deferens in vivo. The longitudinal tensile and internal hydrostatic pressure strengths of laser-assisted vasal anastomoses were compared to conventional microsurgical suture anastomoses in the human vas deferens. The LAVA group had a greater mean internal hydrostatic pressure strength (p less than 0.001) and a lesser mean longitudinal tensile strength (p less than 0.001) than the conventional microsurgical group. Further evaluation was performed in the Sprague-Dawley rat model, comparing post-operative fertility, patency, healing and sperm granuloma occurrence among four surgically treated groups and a control group: LAVA, conventional suture anastomosis, sham operated, and vasectomized. Light and scanning electron microscopic examination revealed equivalent healing in both the LAVA and conventional groups. Fertility was not statistically different in the LAVA, conventional, control, and sham operated groups. However, the incidence of gross sperm granulomas observed in the LAVA group (80%) was much higher than in the conventional suture anastomosis group (0%). In conclusion, laser-assisted vasal anastomosis is a fast and simple technique for vasal reanastomosis and was as successful (in pregnancies) as conventional suture anastomosis in producing fertility in rats undergoing vasal reanastomosis, but the incidence of sperm granuloma is higher.     

Injury to the pre-pubertal vas deferens. II. Experimental repair.

We have previously shown that the human vas deferens does not change in cross-sectional size between birth and the middle of puberty. This suggests that if the human vas is injured prior to mid-puberty, repair by a traditional microsurgical vasovasostomy may be technically difficult. We propose that a chromic stent can be used to assist in the repair of vas injured before mid-puberty. This hypothesis was tested in Sprague-Dawley rats. At three weeks of age, male offspring were divided into three groups (eight to nine rats/group): 1) Sham group--a sham operation at three weeks, 2) VV group--bilateral transection of vasa at three weeks followed by a delayed repair at eight weeks by microsurgical vasovasostomy without a stent, 3) Stent group--bilateral transection of vasa at three weeks followed by immediate repair by aligning the lumens with a 6-0 chromic intravasal stent (suture) and holding the transected ends together with several seromuscular sutures. At four months all rats were fertility tested and a score was given to each rat (mean number of concepti among three females for each male rat). Analysis of anastomotic patency by flow rates and histology was performed. There was no statistical difference in the mean fertility score of 6.85 in the Stent group compared to 7.83 in the Sham group. However, a fertility score of 0.71 in the VV group was significantly decreased compared to the Stent and Sham group (p = .0003), despite no statistical difference between the groups in patency. This suggests that a recognized injury to the pre-pubertal human vas should be immediately repaired and the repair can be done using 6-0 chromic suture as an intravasal stent to help align the lumina of the smaller pre-pubertal vas.     

显微外科吻合术治疗医源性腹股沟输精管梗阻

目的总结腹股沟区手术输精管损伤后的再通治疗经验。方法2005年7月至今收治11例有双侧腹股沟手术史的梗阻性无精子症患者,手术探查腹股沟区均证实输精管损伤,完全离断4例,断端以细弱瘢痕相连的7例,采用手术显微镜下精微对位多层吻合输精管再通术。结果全部病例中10例行再通手术,7例术后精液检测发现精子。结论腹股沟区手术损伤后的输精管再通手术难度较大,显微镜下精微对位多层吻合输精管再通术是治疗腹股沟区输精管损伤的首选方案。     

Reconstructive microsurgery of the vas deferens. Experimental study of suture materials

Microsurgery is the procedure of choice for vasectomy reversal. The aim of this study was two compare two different suture materials for vasovasectomy - a nonresorbable material (nylon 10/0 with a BV 6 needle), which is widely used, and a resorbable material (polyglycolic acid, also with a BV 6 needle), which has not yet been evaluated for this use. 28 Sprague-Dawley rats were operated on under microscope. Two groups were then compared, group A with nylon (n = 14) and group B with polyglycolic acid (n = 14). In each group, 8 animals had a vas deferens section and 6 had a previous vasectomy by ligature. Ten days postoperatively, the patency rate of the anastomosis was evaluated by the presence of sperm on both sides of the suture line. The contractility was assessed by mechanical stimulation. The existence of a sperm granuloma was considered as indicative of a non functional anastomosis. Three days later a fertility test was performed, lasting three months, and the number of litters was checked. The rats were sacrificed after three months, and each vas deferens was examined histologically or by electron microscope. The macroscopic results were: 57% patent anastomoses in group A and 77% in group B. 16% patent anastomoses after ligature in group A (n = 6) and 75% in group B (n = 6). The pregnancy rate was 54% in group A and 77% in group B. After previous ligation, the corresponding figures were 20% and 83% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Absorbable and nonabsorbable sutures in microsurgery: standardized comparable studies in rats

In order to study the applicability and value of synthetic absorbable suture materials in microvascular surgery, 8-0 monofilament nonabsorbable polyamide sutures and 8-0 absorbable polyglycolic acid and polyglactin 910 sutures were used in end-to-end anastomoses of the aorta in rats, employing the same microsurgical model for all procedures. Comparable investigations of the anastomotic sites were carded out macroscopically and histologically at various intervals postoperatively. It was found that when placed under unphysiologic strain, microvascular anastomoses sutured with absorbable materials had less mechanical endurance than anastomoses stitched with nonabsorbable suture materials. It was also found, however, that this had no significance in vivo, inasmuch as no vascular ruptures or aneurysms appeared with either the absorbable or nonabsorbable sutures even after long-term observation. The nonabsorbable sutures were fully recognizable up to 150 days, microscopically showing clear evidence of granuloma formation. The absorbable sutures, on the other hand, could hardly be discerned after 50 days, and after 150 days the foreign body and scar reactions had almost completely disappeared. Absorbable suture materials lead to more rapid restitution of the vascular wall than nonabsorbable sutures and consequently appear to be superior.     

Use of fibrin glue to minimize bleeding of microvascular repairs in hypertensive rats.

The purpose of this study is to describe our technique of applying fibrin glue at the microvascular anastomotic site and to evaluate the effect of fibrin glue on anastomotic hemostasis and patency under various high pressure states using dopamine-induced acute hypertension in rats. A total of 72 male Wistar Kyoto rats, 10 weeks old, were used in this study. Under urethane anesthesia, end-to-end anastomosis of the left femoral artery was performed using 10-0 nylon suture by the standard interrupted suture technique. Pasteurized fibrin glue was then topically applied upon the suture line of the anastomosis. Thirty-six normotensive rats were divided into three groups based on the number of sutures (4, 6, or 8) used to complete the anastomosis. Groups were subdivided, half receiving fibrin glue application and half without. Thirty-six dopamine-induced acutely hypertensive rats were divided into three groups based on the blood pressure levels of 150, 200, and 250 mmHg, respectively. These groups were again subdivided, with half receiving glue applications. Microvascular anastomosis was performed using 6 nylon sutures. Patency rates and anastomotic bleeding were evaluated. The results revealed that successful anastomoses could be performed with fewer sutures when fibrin glue was used as a reinforcement at the anastomosis. Fibrin glue was also effective at the maximum blood pressure (250 mmHg) with no anastomotic leakage and no decrease in postoperative patency rate. These results suggest that conventional microsurgical suturing technique combined with fibrin glue would be effective in the prevention of leakage in microsurgical repairs, even under conditions of high blood pressure.     

Laser welding of vas deferens in rodents: Initial experience with fluid solders

This study evaluates the use of sutureless laser welding for vasovasostomy. In 14 rodents, the left vas deferens underwent vasovasostomy using an albumin-based solder applied to the adventitia of the vas deferens. The solder contained the dye, indocyanine green, to allow selective absorption and denaturation by a fiber-coupled 800-nm diode laser. The right vas deferens served as a control, receiving conventional layered microsurgical repair. We used a removable 4/0 nylon stent and microclamps to appose the vas deferens during repair, with no need for stay sutures. The mean time to perform laser solder repair (23.5 min) and conventional repair (23.3 min) were not significantly different (P = 0.91). However, examination after 8 weeks showed that granuloma formation (G) and patency (P) rates for the conventional suture technique (G, 14%; P, 93%) were significantly better than observed for the laser solder technique (G, 57%; P, 50%). © 1998 Wiley-Liss, Inc. MICROSURGERY 18:414–418, 1998     

Toward a sutureless vasovasostomy: use of biomaterials and surgical sealants in a rodent vasovasostomy model

PURPOSE: With 500,000 to 800,000 vasectomies performed annually and a reversal rate of 3% to 8% vasectomy reversal has become a commonly performed procedure. Two-layer microsurgical vasovasostomy remains the gold standard for surgical reconstruction of the vas. However, this procedure is technically demanding and time-consuming. We determined the ability of biomaterials and surgical sealants to decrease the number of sutures used, enhance anastomosis watertightness and decrease operative time. MATERIALS AND METHODS: Adult male Wistar rats underwent vasectomy 2 weeks prior to vasovasostomy. Standard 2-layer microsurgical repair was performed in control animals. Experimental groups underwent 3-suture mucosal approximation and then completion of the anastomosis with a biomaterial membrane and/or synthetic sealant. The rats were sacrificed 9 weeks after vasovasostomy. Anastomotic patency was assessed functionally by the presence of motile sperm in the vas distal to the testes and anastomosis, and mechanically by methylene blue vasogram. The presence and size of sperm granulomas were also recorded. RESULTS: Microsurgical vasovasostomy required significantly less time when biomaterial (42.7 minutes) or sealant (40 minutes) was used compared to the standard sutured group (102.5 minutes, each p < 0.001). There was no difference in patency between the standard sutured and biomaterial groups (90% vs 92%). Patency was significantly lower in the sealant groups, that is 70% in the suture, biomaterial and sealant group, and 75% in the suture and sealant group. The biomaterial group had only 1 sperm granuloma in 12 procedures, which was significantly better than the 7 in the control group (p <0.001). CONCLUSIONS: Using a biomaterial wrap during vasovasostomy resulted in significantly decreased operative time and fewer sperm granulomas than in the control group. Sealants were not effective. Biomaterial wrap may support vasovasostomy and by decreasing leakage improve the outcome.     

Microvascular anastomosis with absorbable and nonabsorbable sutures--a comparative study in rats

Polyglycolic acid, polypropylene, and nylon sutures were used to anastomose the aortas of 40 rats. Comparative studies of the healing process at the suture sites were performed. The long-term observations, by means of light and scanning electron microscopy, revealed that the regeneration of endothelium was more rapid and the endothelium had a smoother surface in the aortas that received the polyglycolic acid sutures than in the aortas receiving polypropylene or nylon sutures because the polyglycolic acid sutures were absorbed after 6 weeks. It was concluded that polyglycolic acid suture material may be more desirable than nonabsorbable suture material in microvascular anastomoses.     

Microvascular anastomosis with absorbable and nonabsorbable sutures—A comparative study in rats

Polyglycolic acid, polypropylene, and nylon sutures were used to anastomose the aortas of 40 rats. Comparative studies of the healing process at the suture sites were performed. The long-term observations, by means of light and scanning electron microscopy, revealed that the regeneration of endothelium was more rapid and the endothelium had a smoother surface in the aortas that received the polyglycolic acid sutures than in the aortas receiving polypropylene or nylon sutures because the polyglycolic acid sutures were absorbed after 6 weeks. It was concluded that polyglycolic acid suture material may be more desirable than nonabsorbable suture material in microvascular anastomoses.     

In vivo studies on the tensile strength loss of absorbable synthetic threads

In a total of eight experimental groups, PGS, PGS-S, PGS-C, and polyglactin 910 sutures were implanted subcutaneously in rats. The sutures were either sterile or contaminated with staphylococcus. They were removed after 7, 14, 21, and in two groups after 28 days. The linear loss of tensile strength was tested by means of an electronic tensile strength measuring machine. In four additional groups, the same studies were carried out with paraffinized PGS sutures and in localizations in stomach, duodenum and colon. The diameter of the filament has an effect on the loss of tensile strength: initially more rapid in fine filaments and later, retarded in comparison to thicker filaments. Coating of the suture has almost no influence on tensile strength, although contaminated sutures show a comparative decrease. In intraenteral localizations, loss of tensile strength can be expected to occur much more rapidly than in subcutaneous ones. Paraffinization does not delay decrease in tensile strength. Polyglactin 910 sutures of the second generation employed subcutaneously, show a much higher loss of tensile strength on the day 7 than PGS sutures; by day 28 the relationship is reversed.     

Fibrin glue vasal anastomosis compared to conventional sutured vasovasostomy in the rat

Vasectomy reversal has become a frequently performed surgical procedure with best results obtained with the use of the operating microscope and microsurgical technique. The present study was undertaken to evaluate the use of fibrin glue ("Tisseel", Immuno U.S., Inc.) for vasovasostomy and to compare this technique to conventional sutured vasovasostomy. Utilizing 60 male Sprague Dawley rats, a conventional two layered sutured anastomosis of vasovasostomy (30 rats) was compared to a fibrin glue technique of vasal anastomosis (30 rats). The fibrin glue technique was performed with two transmural sutures, was unstented, and utilized the biological glue to seal the anastomosis. The contralateral vas of each animal underwent vasectomy and reapproximation of unligated ends so that the rate of spontaneous recanalization could be accessed. Rats were sacrificed at 24 hours, one week, four weeks, and three months postvasovasostomy. The vasal specimens were evaluated for gross patency, presence and size of sperm granuloma, mean flow rates at varying infusion pressures, tensile strength measurements and histologic studies. Combining the one and three month groups, a similar patency rate was obtained by either technique; 83% (n = 18) for the sutured group, and 90% (n = 21) for the fibrin glue group. The rate of spontaneous recanalization of the contralateral vasa in the one and three month animals was 8% (n = 38). The mean flow rates obtained at high and low infusion pressures were not statistically different for the two techniques. The tensile strength of the glue anastomosis averaged 78% of the tensile strength achieved by the conventional sutured technique. The incidence of sperm granuloma after vasovasostomy was 28% for the fibrin glue group and 61% for the sutured group. Additionally, 67% of granulomas were small (less than 3 mm.) in the glue group, compared to only 36% in the sutured group. Histology revealed similar morphological changes in the area of anastomosis with either technique. Operative time for sutured vasovasostomy averaged 24 minutes, compared to an average of 11 minutes for the glue assisted vasovasostomy. The use of fibrin glue allowed the performance of a sperm tight patent anastomosis that had the advantages of reduced incidence of sperm granuloma formation, reduced operative time, and less microsurgical skill required to perform the anastomosis.     

A modified single-armed technique for microsurgical vasoepididymostomy

This study is to evaluate the effectiveness of a modified single-armed suture technique for microsurgical vasoepididymostomy (VE) in patients with epididymal obstructive azoospermia. From September 2011 to December 2011, microsurgical two-suture longitudinal intussusception VEs were performed using our modified single-armed suture technique in 17 men with epididymal obstructive azoospermia at our hospital. Two of these patients underwent repeated VEs after previous failed VEs, and one patient underwent unilateral VE because of an occlusion of the left abdominal vas deferens. The presence of sperm in the semen sample at 3 months postoperation was used as the preliminary endpoint of this study. Each patient provided at least one semen sample at the 3-month time point, and the patency was assessed by the reappearance of sperm (>10⁴ ml⁻¹) in the semen. The mean operative time for the modified technique was 219 min. Patency was noted in 10 men (58.8%), including one patient who underwent repeated VE. The patient who underwent unilateral anastomosis manifested no sperm postoperatively in his semen. Sperm granulomas were not detected in this cohort. The results of this study demonstrate that our modified technique for microsurgical longitudinal intussusception VE is effective. We believe that it is a practical alternative that may reduce operation time and obviate the suture crossing.     

Evaluation of a fibrin sealant free of bovine-derived components in an experimental vas anastomosis study

OBJECTIVES: The risk of transmission of bovine spongiform encephalopathy cannot be excluded from the use of bovine-derived products. The present study was undertaken to evaluate the performance of a new fibrin glue free of bovine-derived components in vas anastomosis and to compare this product to conventional vas anastomosis with fibrin glue. METHODS: Bilateral delayed vas anastomosis was performed in 40 Sprague-Dawley rats. All animals underwent a fibrin glue-assisted vas anastomosis with three transmural sutures tied prior to fibrin glue application. The composition and preparation of fibrin glue was similar for all vas anastomoses except the fibrinolysis inhibitor component which was aprotinin (3,000 KUI/ml) in group 1 and tranexamic acid (10 mg/ml) in group 2. The animals (20 rats in both groups) were sacrificed 7 weeks postoperatively and evaluated for gross patency, presence of sperm granuloma and tensile strength measurements at the anastomosis site. RESULTS: No difference was found between the 2 groups for all parameters evaluated whether a bovine-derived or a synthetic fibrinolysis inhibitor component was used. CONCLUSION: This study showed that tranexamic acid, a fibrinolysis inhibitor, can be substituted for conventional fibrin glue thereby avoiding the risks of bovine products.     

Intravasal azoospermia: a surgical dilemma

OBJECTIVES: To determine the incidence of intravasal azoospermia (IVA) and evaluate which factors before and during surgery influence outcome, by prospectively and intentionally performing bilateral vasovasostomies (VVs) only in men with intraoperative IVA. PATIENTS AND METHODS: Using a multilayer technique, 472 men underwent microsurgical reconstructive procedures. Intravasal fluid was examined for sperm by the surgeon and a pathologist. Strict enrolment criteria included total absence of sperm or sperm parts and bilateral VV as a treatment procedure. Patients were followed up by semen analysis and paternity assessed only by naturally conceived pregnancies. RESULTS: Of the 472 patients, 27 (5.7%) had bilateral IVA; 15 of these patients were available for a follow-up of 1-47 months. Eleven patients had identical gross appearance of intravasal fluid bilaterally. Of these patients, five had sperm in the ejaculate after surgery (three with clear intravasal fluid and two with no fluid). Bilaterally different vasal fluid was found in four men. Unilateral clear fluid was present in three patients, two of whom had sperm in semen analysed after VV. Overall, there was sperm in the ejaculate in seven of 15 patients with IVA; five of these seven had clear fluid in at least one vas deferens. One patient with unilaterally clear fluid achieved paternity by a naturally conceived pregnancy. The difference between the mean (SEM) obstruction interval in men who had sperm in a semen sample after VV, at 16.7 (3. 30) years, and in persistently azoospermic patients, at 15.5 (1.89) years, was not statistically significant (P = 0.741). CONCLUSION: The results of VV in patients with IVA are unsatisfactory; the patency rate is higher in men with copious clear fluid in at least one vas. The obstructive interval in patients with IVA does not appear to influence the outcome of VV.     

Common bile duct healing. Do different absorbable sutures affect stricture formation and tensile strength?

Few basic investigations have addressed the problem of common bile duct strictures. We systematically investigated the healing canine end-to-end choledochal anastomosis and tested the hypothesis that common bile duct anastomoses sutured with monofilament polyglyconate absorbable suture would heal with less stricture formation and greater tensile strength than those sutured with braided polyglactin 910 and chromic catgut sutures. Seventy-six canines, randomized to control vs sutured groups, underwent either mobilization (controls) or transection of the mid-common bile duct and were allowed to heal 5, 10, 15, or 50 days postoperatively before sacrifice. The type of absorbable suture used to construct a common bile duct anastomosis was found to have no major effect on anastomotic strictures nor on anastomotic breaking strength. Polyglyconate suture caused significantly less perianastomotic inflammation than did chromic suture, with polyglactin 910 sutures evoking an intermediate inflammatory response. Surgeons may safely choose sutures for biliary procedures based on the clinical circumstances and personal preference.     

In-vivo comparison of four absorbable sutures: Vicryl, Dexon Plus, Maxon and PDS

Absorbable sutures are initially equal or superior to nonabsorbable sutures in terms of tensile strength but are absorbed at variable rates by the action of hydrolysis. This study demonstrated that the in-vivo half-life tensile strength of the braided absorbable sutures polyglycolic acid (Dexon Plus) and polyglactin 910 (Vicryl) is 2 weeks, whereas those of the monofilament absorbable sutures polyglyconate (Maxon) and polydioxanone (PDS) are 3 and 6 weeks respectively. The addition of a single hitch or six knots reduced the in-vitro tensile strength by 30% to 35%. Polyglyconate (Maxon) suture demonstrated the best in-vitro knot security.     

Microsurgical vasoepididymostomy: a prospective randomized study of 3 intussusception techniques in rats

PURPOSE: Vasoepididymostomy is a technically challenging but cost-effective treatment for obstructive azoospermia. We evaluated the outcomes of 3 intussusception vasoepididymostomy techniques, namely 3 suture triangulation, 2 suture transverse and a new 2 suture longitudinal technique. MATERIALS AND METHODS: Male Wistar rats were randomized into 4 experimental and 1 control groups. After 3 weeks of vasal obstruction bilateral vasoepididymostomy was performed. In group I, 3 sutures were placed in triangular fashion. In group II, 2 sutures were placed perpendicular to the tubule. In group III, 2 sutures were placed longitudinal to the tubule. The tubules were then opened in the direction of the needles and anastomosed to the vasa. After 5 months patency was evaluated in blinded fashion. RESULTS: The functional patency rate (presence of motile sperm in the vas) was 64%, 64% and 93% in groups I to III, respectively (p <0.001). As evaluated by methylene blue retrograde vasography toward the epididymis, the mechanical patency rate was similar for the 3 techniques, that is 86%, 86% and 93% in groups I to III, respectively. The sperm granuloma rate was significantly lower in group III (36%, 21% and 0% in groups I to III, respectively, p <0.001). CONCLUSIONS: Transverse 2 suture vasoepididymostomy has a patency rate similar to that of the 3 suture technique. Our new 2 suture longitudinal technique, which allows a larger opening in the epididymal tubule for anastomosis, is superior to the 2 and 3 suture techniques with respect to the patency and sperm granuloma rates.     

Genius,Creativity, and Leadership

Research in reduced suture fibrin glue (FG) and sutureless FG anastomosis has been lagging behind FG utilization in other surgical fields. A review of the literature for vascular, esophageal, tracheal, gastrointestinal, common bile duct, ureteral, vas deferens, and Fallopian tube FG anastomosis indicates that reduced suture FG and sutureless FG procedures may be performed with less training, reduced operating time, leakage, ischemia, inflammation, and necrosis compared to sutured techniques. Reduced suture FG vasular anastomosis augments early anastomotic strength. Suture number for esophageal, tracheal, and tracheobronchial anastomoses can be reduced with FG. Bursting strength in pig small intestine and rat colon was lower at 4 days postoperatively, but returned to sutured strength at 7 days. Mortality was unaffected, and 18-month follow-up in sutureless FG intestinal anastomosis in pigs showed no stenosis. Preliminary ureteral studies have demonstrated successful sutureless FG and reduced suture FG laparoscopic techniques in pigs. Reduced suture FG and sutureless FG vas deferens anastomosis may reduce sperm granuloma rates, with increased patency and pregnancy rates. Patency and pregnancy rates have been similar for tubal FG, reduced suture FG, autologous fibrin glue (AFG), and sutured anastomosis. Any risk of viral transmission or immune response is eliminated by AFG. While there are few studies in many areas of FG hollow vessel anastomosis, the current literature illustrates many of the advantages of FG over other anastomotic techniques and should provide impetus for continued research in this promising field of surgery.