Histology of the divided vas.

Histologic studies were done after experimental vasectomy in the rat in order to investigate spontaneous reanastomosis of the vas after vasectomy; this condition was reported in a case where granulomas at the site of previous divisions were found containing epithelium which had canalized to restore continuity of the vas. In 12 rats through a transverse lower abdominal incision one vas was mobilized doubly ligated 2 cm distal to the epididymis and divided between the ties. Vasa were ligated with 5/0 black silk and 3/0 chromic catgut. After 5 months fixed testes and vasa from the vasectomized side compared with normal counterparts on the contralateral side were found to have swellings at the site of vasectomy (in 8). The swellings were thin-walled sacs which were continuous with the proximal end of the vas; spermatozoa were found in the lumen of both vas and sac. Methods to prevent joining of the sac with the distal vas must be improved.