[Correlation between serum FSH and histological findings on testicular biopsy in men with azoospermia and severe oligozoospermia].

In 51 infertile men with azoospermia or severe oligozoospermia the histological findings on testicular biopsy were compared with the preoperative serum FSH level. In cases of absence of spermatogenesis on testicular biopsy the FSH showed the expected highly significant "feed back" increase, whereas in cases of functioning, but highly pathological spermatogenesis the serum FSH level gave no indication of the type of dysspermatogenesis. Normal FSH levels were found in over 90% of men showing normal spermatogenesis with obstructive azoospermia. Hence, complete inspection of the testis, with attempted demonstration of spermatozoa in the epidydimis, is essential in these cases during testicular biopsy in order to avoid an unnecessary secondary operative refertilizing procedure (epidydimovasostomy) when the site of obstruction is the rete testis.