Morphologic changes of the vas deferens after vasectomy and vasovasostomy in dogs

The fine structure of the vas deferens was studied by SEM and TEM after vasectomy and delayed vasovasostomy in 18 dogs. Mucosal changes were observed in the testicular end of the vas deferens after vasectomy. Identical changes have been observed in the vas deferens in humans after vasectomy. Microsurgical vasovasostomy resulted in reappearance of normal epithelial cells lining the lumen of the vas deferens by means of squamous metaplasia. In six dogs, prevasectomy and postvasovasostomy sperm counts were compared. These counts returned to normal levels, but they never reached or exceeded the prevasectomy values.