Microsurgical TESE and the distribution of spermatogenesis in non-obstructive azoospermia.

We wished to map the distribution of spermatogenesis in different regions of the testis in 58 men with non-obstructive azoospermia, and to develop a rational microsurgical strategy for the testicular sperm extraction (TESE) procedure. One goal was to maximize the chances for retrieving spermatozoa from such men, to minimize tissue loss and pain, and to preserve the chance for successful future procedures. Another goal was to expand upon the previously reported quantitative histological analysis of testicular tissue in 45 azoospermic men undergoing conventional TESE, this time using microsurgical as well as histological mapping. Tubular fullness observed at microsurgery and the presence of spermatozoa in the TESE specimen was compared with the quantitative histological analysis of spermatogenesis. Thus, our conclusions about the distribution of spermatogenesis are based on our experience with TESE in 103 consecutive cases of non-obstructive azoospermia. It was confirmed that men with non-obstructive azoospermia caused by germinal failure have a mean of 0 to 3 mature spermatids per seminiferous tubule in contrast to 17-35 mature spermatids per tubule in men with normal spermatogenesis and obstructive azoospermia. The former represented the threshold of quantitative spermatogenesis which must be exceeded in order for spermatozoa to 'spill over' into the ejaculate. Both testicular 'mapping' by multiple biopsy (n = 15) and microsurgical removal of contiguous strips of testicular tissue (n = 43) revealed a diffuse, rather than regional, quantitative distribution of spermatogenesis. A microsurgical approach resulted in the minimal amount of tissue loss and minimal-to-no pain (compared with the original 45 cases already reported). By this means it is often possible to immediately locate the few tubules with spermatogenesis at microsurgery, under local anaesthesia. But even in cases where greater amounts of tissue must be removed in order to find spermatozoa, the microsurgical TESE procedure prevents secondary testicular damage by protecting blood supply and preventing pain and atrophy from increased testicular pressure. Thus, future attempts at TESE-ICSI need not be compromised.