Microrecanalization after vasectomy in man.

Previously spermatozoa in the semen of vasectomized men were reported in 62 of 63 specimens from 24 men 2 to 31 years postvasectomy (Freund and Couture, 1982). A morphologic basis and term, "microrecanalization," was proposed for this observation. Serial sections (5 mu at 200-mu intervals) of 40 specimens removed at vasovasostomy from 20 men (2 to 14 years postvasectomy) were examined and microcanals (small epithelial-lined channels) were demonstrated in 27 specimens from 18 men. In nine of the 27 specimens, spermatozoa or sperm heads were found within the microcanals. Microcanals occurred in smooth muscle, connective tissue and scar tissue, in each segment, testicular, central and abdominal, in the presence or absence of the vas deferens. Microcanal continuity was traced for 200 to 1140 microns by computerized image analysis. Microrecanalization is characterized by the absence of inflammation or sperm extravasation and is histologically distinct from vasitis nodes or sperm granuloma. Microrecanalization provides morphologic and physiologic bases for the protection of the testis and maintenance of spermatogenesis in man after vasectomy.