Distribution of spermatogenesis in the testicles of azoospermic men: the presence or absence of spermatids in the testes of men with germinal failure [published erratum appears in Hum Reprod 1998 Mar;13(3):780]

The aim of the study was to determine whether a prior diagnostic testiclebiopsy can predict success or failure of testicular sperm extraction (TESE)with intracytoplasmic sperm injection (ICSI) in patients withnon-obstructive azoospermia caused by testicular failure, and what is theminimum threshold of sperm production in the testis which must be surpassedfor spermatozoa to reach the ejaculate. Forty- five patients withnon-obstructive azoospermia caused by testicular failure underwentdiagnostic testicle biopsy prior to a planned future TESE-ICSI procedure.The diagnostic testicle biopsy was analysed quantitatively, and correlatedwith the quantitative findings of spermatogenesis in patients with normalspermatogenesis, as well as with the results of subsequent attempts atTESE-ICSI. Men with non- obstructive azoospermia caused by germinal failurehad a mean of 0-6 mature spermatids/seminiferous tubule seen on adiagnostic testicle biopsy, compared to 17-35 mature spermatids/tubule inmen with normal spermatogenesis and obstructive azoospermia. These findingswere the same for all types of testicular failure whether Sertoli cellonly, maturation arrest, cryptorchidism, or post-chemotherapy azoospermia.Twenty-two of 26 men with mature spermatids found in the prior testisbiopsy had successful retrieval of spermatozoa for ICSI, 12 of theirpartners became pregnant, and are either ongoing or delivered. The studysuggests that 4-6 mature spermatids/tubule must be present in the testisbiopsy for any spermatozoa to reach the ejaculate. More than half ofazoospermic patients with germinal failure have minute foci ofspermatogenesis which are insufficient to produce spermatozoa in theejaculate. Prior diagnostic testicle biopsy analysed quantitatively (forthe presence of mature spermatids) can predict subsequent success orfailure with TESE-ICSI. Incomplete testicular failure may involve a sparsemulti-focal distribution of spermatogenesis throughout the entire testicle,rather than a regional distribution. Therefore, it is possible that massivetesticular sampling from many different regions of the testes may not benecessary for successful TESE-ICSI.