New nonabsorbable stent versus a microsurgical procedure for vasectomy reversal: evaluating tissue reactions at the anastomosis in rabbits.

OBJECTIVE To investigate whether a newly designed nonabsorbable polymeric stent for the reconstruction of the vas deferens provided less stricturing at the site of the anastomosis in comparison with the conventional microsurgical reconstruction of the vas deferens. DESIGN Prospective randomized study in 26 rabbits, comparing the one-layer microscopic sutured procedure with a biocompatible stent. SETTING University animal laboratory center. INTERVENTION(S) Pre- and postoperative average total sperm count, motility, and progressive motile sperm density (PMSD) levels were measured. Histologic sections were taken from the area of the anastomosis, testes, and epididymi after final semen analysis. MAIN OUTCOME MEASURE(S) Rates of stricture and semen parameters. RESULT(S) The vas deferens of the rabbits that received a stent showed an inflammatory reaction within the vas wall adjacent to the stent. Transmural histiocytic or eosinophilic reactions were seen in 2/13 (15%) of the stented animals, with atrophy of the epithelium. Histologic cross-sections of the stented vas deferens demonstrated patency. Microscopically sutured rabbits showed more partial obstructions at the site of the anastomosis (5/13 [38%]) with transmural infiltration of lymphocytes and histiocytes. Despite these partial obstructions the vasa were patent. There was a statistically significant difference in favor of the stent with respect to the total sperm count (P=.05). No differences were seen in motility (P=.057) or PMSD (P=.13). CONCLUSION(S) The newly developed stent provided patency rates comparable with the conventional one-layer microscopic procedure but showed significantly less stricturing of the anastomoses.