Use of epididymal sperm for assisted reproduction in men with acquired, irreparable obstructive azoospermia.

Microsurgical epididymal sperm aspiration (MESA) and in vitro fertilization (IVF) is primarily offered to men with congenital absence of the vas deferens (CAVD). However, the IVF capacity of these epididymal sperm is low ( < 15%) and unpredictable. In this study, IVF and intracytoplasmic sperm injection (ICSI) results in patients with non-congenital, irreparable obstructive azoospermia were analysed. Thirty-three patients were evaluated for a total of 37 cycles of MESA and IVF. Most had obstruction secondary to failed vasectomy reversal and to epididymal blockage. The overall fertilization rate was 30% with regular IVF and 26% with ICSI, and six clinical pregnancies were obtained. Both rates are significantly higher than the IVF rate previously reported with sperm from men with CAVD (13%, P < 0.00001). In men with non-congenital obstructive azoospermia, a significant difference was found in the average sperm count (56.9 x 10(6) v. 12.3 x 10(6), P < 0.04) and total motile count (16.6 x 10(6) v. 1.6 x 10(6), P < 0.01) respectively for patients who achieved IVF and those who did not. It is concluded that (a) the real IVF capacity of human epididymal sperm is 30%, or 42%, if calculated only for patients who achieved fertilization, (b) this higher rate is an indirect support of the hypothesis that sperm from men with CAVD have intrinsic biochemical defects, related to cystic fibrosis mutations, responsible for their low and unpredictable IVF rate, and (c) MESA and IVF can be offered at the same time or as an alternative to patients requesting vasectomy reversal.