[Preclinical trials for mastering intracytoplasmic injection of a sole spermatozoid for the treatment of male infertility].

Before starting with the clinical application of ICS, aged unfertilized oocytes were gathered for training and were injected with a single sperm or without a spermatozoon as a control group for activation. Oocyte damage, initially as high as 40% was reduced to 15% after 60 oocytes. Normal fertilization (2PN) occurred in 18% of the injected oocytes. After this training period 1,488 metaphase II oocytes collected during 144 cycles were used for ICSI. Results were split up in 3 periods (n = 55, n = 24, n = 57) corresponding to the different improvements made in the technique. Results form ICSI in combination with MESA (n = 6) were analysed separately. Mean fertilization increased from 24% to 77%. Fertilization failures (18% of the cycles during the first period) vanished in the last period. Implantation rate improved from 7.4% to 11.4% and reached finally 26%. Pregnancy rate per oocyte retrieval was 16%, 25% and 54%. For the MESA group fertilization was 28%, implantation rate 17% and pregnancy rate 33% and only one fertilization failure was observed. A total of 50 pregnancies were obtained including 2 obtained after MESA and 2 with cryopreserved embryos. Four healthy children are born, 9 were early abortions, 37 pregnancies are still on-going. Preclinical practice on aged unfertilized oocytes seems useful before starting with clinical ICSI, as high initial oocyte damage could be reduced and subsequent clinical treatment successfully applied. Offering high fertilization and pregnancy rates in cases of infertility with severe male factor it is extremely worthwhile mastering this new technique.