The adverse effects of sperm during vasovasostomy.

The 119 non-splinted vasovasostomies that were performed on 95 rats demonstrated that sperm granulomas were present in 99 per cent of the 49 anastomoses that failed. Anastomoses performed on vasa that contained no sperm resulted in 95 per cent patency without granulomas. This procedure was accomplished in immature animals followed to adulthood or by testosterone suppression of spermatogenesis in adult rats. Alternatively, normal adults with sperm in the vasa were irrigated with normal saline at the time of vasovasostomy and this resulted in decreased numbers of granuloma and dramatically improved success rates. Sperm granuloma formation appears to be an important cause of failure of vasovasostomy in the rat.