Analysis of intra-operative aspirates taken during microsurgical refertilization in obstructive azoospermia--preliminary results. The BMFT Study Group for Microsurgery, Giessen.

The reasons for the discrepancy between 'patency' and 'pregnancy' in the outcome of microsurgical refertilization are partially unknown. The quality of the intra-operative aspirate and of the spermatozoa at the level of the anastomosis are discussed worldwide as important factors influencing the success of fertilization in the case of post-operative patency. In 152 men undergoing microsurgical refertilization (vasovasostomy, tubulovasostomy, microsurgical epididymal sperm aspiration, transurethral resection of the ejaculatory duct), 281 aspirates were classified intra-operatively according to Silber, and post-operatively using the Shorr staining technique. In 62 aspirates a computer-aided sperm analysis (CASA) was performed. The percentage of intact spermatozoa decreased from 94.9% at the caput to 9.4% at the cauda epididymidis. The post-operative classification demonstrated an acceptable correlation (0.71) to all grades of intraoperative classification. There was a good correspondence in Silber 4 and 5 but worse in Silber 1 and 2. In CASA, the percentage of motile spermatozoa was not different between epididymal and post-epididymal aspirates. Furthermore, velocity parameters did not differ significantly, but there was a significantly higher straightness of post-epididymal spermatozoa in comparison to epididymal spermatozoa.