Microsurgical epididymovasostomy in the rat: comparison of end-to-side and two invagination techniques.

Most cases of obstructive azoospermia are caused by epididymal obstruction for which the classical treatment is epididymovasostomy (EVST). We have compared the widely used end-to-side, invaginated end-to-side and invaginated end-to-end operations. Ninety microsurgical two-layer EVST were carried out on rats. The technical advantages were assessed and patency of anastomoses and conception rate, the length of the operation and amount of suture material used measured in each group. There were no significant differences in patencies and conception rate between the three groups. The invagination techniques took significantly less time than the more usual end-to-side operation, and less suture material was used. The invagination techniques are easier to learn, simpler to perform and involve less manipulation, reduce trauma and cause less laceration to the ductus deferens and epididymal tubules. Economically considered, the operations save the expenditure of both time and suture material. Of paramount importance in making the choice is the size of the ductus deferens and that of the epididymal tubules.