Fertilization capability of frozen epididymal sperm for intracytoplasmic sperm injection

Both microsurgical epididymal sperm aspiration (MESA) and intracytoplasmic sperm injection (ICSI) are great advances in assisted reproductive techniqu es. By using the ICSI technique, frozen sperm from the epididymis can resul t in successful fertilization. The epididymal sperm retrieved via MESA can be cryopreserved for an in-vitro fertilization (NF) procedure, thus, making repeat surgical retrieval of sperm unnecessary. We report a retrospective analysis of 24 ICSI cycles in 16 patients with obstructive or nonreconstruc table azoospermia. Fresh epididymal sperm was used in 13 ICSI cycles and fr ozen-thawed epididymal sperm was used in the other 11. We compared the fert ilization capability of ICSI using frozen-thawed epididymal sperm with fres h epididymal sperm. Eleven patients became pregnant and five of these pregn ancies resulted from frozen epididymal sperm. The fertilization rate per oo cyte was 58% with fresh sperm, and 66% with frozen-thawed sperm. The rate o f clinical pregnancy for one embryo transfer was 46% with fresh sperm, and 45% with frozen-thawed sperm. There were no significant differences between fresh and frozen-thawed spermatozoa in the fertilization rate of oocytes o r the clinical pregnancy rate. Our results suggest that we should cryoprese rve supernumerary spermatozoa during a MESA/ICSI procedure in order to avoi d repeated scrotal surgery.