Localization of Sperm During Microdissection Testicular Sperm Extraction in Men with Nonobstructive Azoospermia

Purpose: We determined the location where sperm were identified during microdissection testicular sperm extraction and characterized the subset of patients for whom complete bilateral exploration was most beneficial. Materials and Methods: A total of 900 men underwent a first attempt at microdissection testicular sperm extraction. Sperm extraction began with an initial wide incision in the larger testis. If no sperm were identified, the deeper tissue was extensively microdissected. A similar technique was used on the contralateral testis if no sperm were found on the initial side. Results: In 474 men (52.6%) sperm were identified at the first microdissection testicular sperm extraction. Of these men 308 (65%) had sperm identified through the initial wide incision alone. In men with lower preoperative follicle-stimulating hormone, larger testicular volume, a varicocele history and hypospermatogenesis on preoperative or intraoperative diagnostic biopsy there was a greater chance of finding sperm in the initial wide incision alone (p <0.05). Only 40 of the 506 men (8%) who underwent bilateral testicular microdissection had sperm found on the contralateral side when no sperm were identified on the initial side. In men with Klinefelter syndrome and small testes the chance of sperm retrieval was higher on the contralateral side after negative unilateral microdissection (p <0.05). Conclusions: More than a third of the men with nonobstructive azoospermia required complete microdissection of the testes to identify sperm. Sperm were found on the contralateral side in up to 8% of the men in whom no sperm were identified in the initial testis.