Background: In non-obstructive azoospermic patients (NOA)-besides the mechan ical treatment, vital spermatozoa from the tissue obtained from testes by biopsy can be enzymatically prepared. Objective: To increase the sperm recovery succ es s of testicular sperm extraction (TESE), suitable for ICSI. Study design: Prospe ctive, clinical study. In 177 consecutive men who presented with clinical and la boratory data indicating NOA, tissue samples were obtained by microdissection TE SE method. Initially, mature spermatozoa were searched for by mechanical extract ion technique shredding the biopsy fractions. In cases with no spermatozoa was o bserved after maximum 30 min of initial searching under the inverted microscope, the procedure was then followed by enzymatic digestion using DNAse and collagen ase type IV. In cases of at least a mature spermatozoon could be obtained proper ly, ICSI was performed. Results: Of 177 cases with NOA, conventional mincing met hod extended with enzymatic treatment yielded successful sperm recovery for ICSI in 102 (57%). Overall in vitro tissue-processing time for patients with sperm recovery failure after 30 min of mechanical searching, was between 80 and 105 min (mean 96 ±9). Cleavage, embryo transfer and clinical pregnancy rates in mec hanical plus enzymatic TESE patients were not significantly different from those of only mechanically TESE performed patients (P >0.05). Conclusion: Combination of conventional TESE and enzymatic digestion is an effective method to recover spermatozoa suitable for ICSI. The benefit of the mincing combined with enzyme t o sperm retrieval for NOA is firstly to shorten the mechanical searching time, t hus minimizing further cellular damage as well as exposure to external condition s, and secondly to reduce the number of cases with sperm recovery failures.
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