Unilateral or bilateral testicular biopsy in the era of intracytoplasmic sperm injection

Intracytoplasmic sperm injection has significantly improved the treatment of male infertility. Since only single vital spermatozoa are required for successful fertilization, the value of unilateral or bilateral diagnostic testicular biopsies in patients with azoospermia is controversial. We evaluated differences in bilateral testicular biopsies in azoospermic patients with regard to testicular histology and focal spermatogenesis.

Histopathological results of 100 testicular biopsies from 50 patients (mean age 33.3 years) were reviewed. In all cases azoospermia was the indication for diagnostic testicular biopsy. Intra-individual differences of bilateral testicular biopsies were retrospectively reviewed by determining the latest stage of spermatogenesis.

After bilateral biopsy a difference in testicular histology was found in 28% and identical histopathology was noted in 70% of patients. An unsuspected burned out seminoma with maturation arrest in the contralateral testis was seen in 2% of cases. Testicular symmetry determined by a Prader orchidometer was noted in 54.8% of patients whereas 45.2% had asymmetrical testis. The frequency of divergent histopathologies in relation to testicular symmetry was 21.7 and 26.3%, respectively. Spermatozoa were found in 42% of right and 44% of left testes (p >0.05), and spermatids as the latest stage of differentiation were detected in 14 and 16%, respectively (p >0.05). Differentiation of testicular histologies according to the side of biopsy revealed spermatozoa and/or spermatids in 56% of right and 58% of left testes (p >0.05). Bilateral biopsies increased the detection of focal spermatogenesis to 68%. If only unilateral diagnostic testicular biopsies had been performed, in 20% of patients focal spermatogenesis in the contralateral testis would have been missed.

Bilateral testicular biopsies are superior to unilateral biopsies in the evaluation of patients with azoospermia. A 28% intra-individual difference in testicular pathology was seen after bilateral biopsies, and in 20% of patients focal spermatogenesis would have been missed after unilateral biopsy only. Due to the prognostic relevance of testicular biopsies for successful sperm retrieval before assisted reproduction, bilateral diagnostic testicular biopsies are recommended in the evaluation of patients with azoospermia.