Testicular sperm extraction: impact of testicular histology on outcome, number of biopsies to be performed and optimal time for repetition.

Testicular sperm extraction (TESE) may not always be successful in patients with non-obstructive azoospermia, as they only have minute foci of active spermatogenesis from which a tiny number of spermatozoa can be extracted. The aim of this study was to find the percentile incidence of successful TESE in non-obstructive azoospermia patients in relation to various histopathological patterns and the number of performed biopsies, and to determine the optimal time needed for repetition. A total of 216 patients underwent bilateral testicular biopsy taking a single piece from each testis for sperm retrieval and pathological evaluation. In another 100 patients, the same procedure was done but taking multiple samples (maximum four samples/testis). Spermatozoa were successfully retrieved from 37.5 and 49% of patients who supplied single and multiple samples respectively. TESE was significantly higher when multiple samples were taken in all histopathological groups except for Sertoli cell-only syndrome, tubular sclerosis and Klinefelter's pattern. Twenty-seven patients underwent repeated TESE for ICSI between 1 and 24 months from the first procedure; all of them had easy sperm retrieval during the first procedure. Although sperm retrieval was successful in 75 and 94.7% of patients who underwent the second attempt, before and after 3 months respectively, a second TESE was usually more difficult and necessitated multiple sampling.