Correlation between motility of testicular spermatozoa, testicular histology and the outcome of intracytoplasmic sperm injection.

The objective of the present study was to analyse the influence of motility on the results of intracytoplasmic sperm injection (ICSI) when testicular spermatozoa are used for microinjection and to correlate this with testicular histology. A total of 197 ICSI treatment cycles (167 couples) was analysed retrospectively in which testicular spermatozoa were used, because of complete azoospermia, for microinjection. Fertilization, embryo cleavage, transfer and pregnancy rates were evaluated and compared in relation to motility of testicular spermatozoa. In 170 cycles, histological diagnoses were compared with findings on motility. Injection of motile testicular spermatozoa (in 159 cycles) provided a higher normal fertilization rate than did injection of non-motile spermatozoa (in 14 cycles; 65 versus 45% respectively). Normal spermatogenesis was diagnosed in a significantly higher proportion and incomplete maturation arrest in a significantly lower proportion in the group of patients in which only motile spermatozoa were used for microinjection (65 and 10%), as compared to the group where exclusively non-motile spermatozoa were used (36 and 36%). Fertilization rate after ICSI was relatively high when non-motile testicular spermatozoa were used for microinjection, but use of motile testicular spermatozoa was associated with a still higher fertilization rate (except when histology of the testicular biopsy showed normal spermatogenesis), and therefore selection of motile testicular spermatozoa is always preferable for ICSI. Normal spermatogenesis predicts a greater probability, and maturation arrest a lower probability of recovering motile testicular spermatozoa.