Comparison of absorbable and nonabsorbable sutures for microsurgical vasovasostomy in rats

Objectives. At least 12% of initially patent vasovasostomies (Ws) shut down . Currently, only nonabsorbable sutures are used for W. A synthetic, slowly absorbing, monofilament polyglactin suture has been developed that retains tensile strength for up to 6 months. We performed a prospective controlled randomized study comparing absorbable and nonabsorbable sutures for rat Ws . Methods. Bilateral microsurgical W was performed in three groups of 36 Wist ar male rats, with 10-0 nylon, 10-0 polypropylene, and 10-0 polyglactin sut ures. Twelve control rats underwent sham operations. Three rats in each gro up were killed at 2, 6, 12, and 24 weeks. The abdominal end of the vas defe rens was transected and the intraluminal fluid examined microscopically for presence of sperm. The segment of the vas deferens containing the anastomo sis was excised. Fluid from the testicular end was examined for sperm to co nfirm spermatogenesis. Patency was confirmed by an antegrade indigo carmine vasogram of the anastomotic segment. Segments were randomly sent for histo logic or tensile strength evaluation. Results. The mean tensile strength of the anastomoses performed with nylon was slightly higher than in polypropylene and polyglactin sutures, although the difference was not statistically significant. Polyglactin consistently maintained tensile strength throughout 6 months without significant fluctu ations. The mean patency rate in the polyglactin group was 96%, in nylon 81 %, and in polypropylene 61%. Although polyglactin had a consistently higher patency rate compared with nonabsorbable sutures, the difference was not s tatistically significant (P = 0.11) but indicated a strong trend. The occur rence of microscopic sperm granuloma, muscle layer injuries, intimal fibros is, and adventitial fibrosis of the vas deferens was not significantly diff erent between suture types. Conclusions. The three suture materials appear equivalent with respect to o verall tensile strength of anastomosis; with histologic evaluation, the tre nd was toward better patency with polyglactin. Polyglactin 10-0 microsurgic al suture is a viable alternative to nonabsorbable sutures in microsurgical Ws, although further studies are indicated to assess long-term results. UR OLOGY 53: 1235-1238, 1999. (C) 1999, Elsevier Science Inc. All rights reser ved.