Non-Obstructive Azoospermia

Testicular failure affects approximately 1% of the male population and 10% of men who seek fertility evaluation. Azoospermic men with testicular failure (non-obstructive azoospermia) have either Sertoli cell-only pattern, maturation arrest, or hypospermatogenesis on testis biopsy. Until recently, it was assumed that men with non-obstructive azoospermia were untreatable. The only options offered to these couples to have children were the use of donor spermatozoa or adoption. Several clinically relevant findings have changed our approach to this condition. First, we have observed that direct evaluation of testis biopsy specimens often demonstrates sperm in men with non-obstructive azoospermia, despite severe defects in spermatogenesis.

In addition, it was previously thought that sperm must traverse the male reproductive tract before acquiring the ability to normally fertilize an egg. Our experience with men who have unreconstructable obstructive azoospermia, including congenital absence of the vas deferens suggests that complete transit through the epididymis is not a prerequisite for fertilization. Retrieval of sperm from the testis or epididymis was associated with good pregnancy rates using in vitro fertilization. Our subsequent experience indicated that micromanipulation of gametes during assisted reproduction could improve these pregnancy rates. Subsequently, we have observed that optimized in vitro micromanipulation techniques can further enhance fertilization and pregnancy rates using epididymal or testicular sperm. This leads us to the second important clinical observation, that sperm can be retrieved from the testes of men with obstructive azoospermia and used with the assisted reproductive procedure of intracytoplasmic sperm injection (ICSI) during in vitro fertilization (IVF) with a high chance of achieving pregnancies and deliveries of normal children. These findings have led investigators from Belgium and elsewhere to perform testicular sperm extraction (TESE) with ICSI for men with non-obstructive azoospermia. Low pregnancy rates of 20 to 21% per attempt have been reported.