Frozen-thawed epididymal spermatozoa for intracytoplasmic sperm injection

Area of Science:

• Reproductive Medicine
• Andrology
• Infertility Treatment

Background:

• Epididymal spermatozoa can be retrieved surgically and cryopreserved for later use in assisted reproductive technologies.
• Severe oligoasthenospermia-teratozoospermia presents challenges for conventional in vitro fertilization (IVF).
• Intracytoplasmic sperm injection (ICSI) is a key technique for overcoming male infertility factors.

Purpose of the Study:

• To evaluate the efficacy of frozen-thawed epididymal spermatozoa in ICSI cycles.
• To compare fertilization and pregnancy outcomes with fresh ejaculated spermatozoa.
• To assess the impact of sperm vitality on ICSI success rates.

Main Methods:

• Retrospective analysis of ICSI cycles utilizing frozen-thawed epididymal spermatozoa.
• Comparison with cycles using fresh ejaculated spermatozoa in cases of severe sperm parameter abnormalities.
• Epididymal sperm aspiration via microsurgery followed by cryopreservation and ICSI.

Main Results:

• Fertilization rate using frozen-thawed epididymal spermatozoa was 47%, significantly lower than fresh ejaculated spermatozoa (73%).
• Embryo implantation and clinical pregnancy rates per transfer were similar between the two groups (18.4% vs. 27.0%).
• Higher prefreeze sperm vitality (>20%) correlated with significantly improved fertilization (56% vs. 22%) and embryo cleavage rates (91% vs. 57%).

Conclusions:

• Routine collection and cryopreservation of epididymal spermatozoa enable successful ICSI cycles with outcomes comparable to ejaculated spermatozoa.
• Low sperm vitality (<20%) in aspirated samples is a critical factor impacting fertilization and suggests the need for alternative sperm sources.
• Cryopreserved epididymal sperm offers a viable option for multiple ICSI treatment cycles.