Biological aspects of testicular sperm extraction

Cumulative pregnancy rate after ICSI with cryopreserved testicular tissue in non-obstructive azoospermia

The aim of the present study was to describe a simplified and inexpensive method of testicular tissue freezing, to assess the cumulative clinical pregnancy rate (CPR) by this technique, and to provide useful information for counselling couples with non-obstructive azoospermia. One hundred and sixty-five couples with non-obstructive azoospermic males pursuing assisted conception, from December 1995 to December 2002, were included. In all cases, the testicular tissue retrieved by open multiple-biopsy (both sides, by testicular sperm extraction) was frozen using a simple liquid nitrogen vapour freezing technique and was stored in liquid nitrogen thereafter. Only mature spermatozoa were used for intracytoplasmic sperm injection (ICSI) after thawing. Expected CPR were calculated using the Kaplan-Meier survival analysis. A total of 281 cycles were performed resulting in 53 clinical pregnancies. Crude and expected CPR (95% confidence intervals) after three cycles were 32.1 (25.7-40.1) and 55.7% (37.0-74.4) respectively. In conclusion, this simplified method for freezing testicular tissue resulted in a satisfactory outcome after ICSI in cases of non-obstructive azoospermia.

Retrospective multicentre study on mechanical and enzymatic preparation of fresh and cryopreserved testicular biopsies

BACKGROUND

Isolation of sperm suitable for ICSI from fresh or frozen-thawed testicular sperm extraction (TESE) can be facilitated by mechanical or enzymatic processing of the samples.

METHODS

A retrospective multicentre study was initiated to compare these two approaches. Eleven German centres provided data on their TESE cycles performed during the period 1996/1997. Quality of retrieved sperm, fertilization rates of injected oocytes, embryo quality, resulting pregnancy rates and evolution of pregnancies were evaluated.

RESULTS

The percentage of cycles with at least some motile sperm available for injection was higher after mechanical preparation. Independent of the preparation method, fertilization rates were higher for motile compared with immotile sperm or elongated spermatids in all groups and in general higher for cryopreserved versus fresh samples. Embryo quality was significantly better after injection of motile sperm for all treatments and in particular after enzymatic versus mechanical processing of biopsies. Pregnancy rates were identical for embryos derived from sperm prepared mechanically or enzymatically from fresh or cryopreserved testicular samples. The abortion rate (32/172, 18.6%) and the rate of multiple implantations (32/140, 22.9%) were not different from results reported in the literature for ICSI using ejaculated sperm.

CONCLUSION

In this retrospective multicentre study, no unequivocal advantage of one over the other preparation method could be identified in 839 ICSI cycles using testicular sperm from 549 patients.