[Micromanipulatory sperm injection--a new method in the treatment of infertile males].

Three couples were selected for this preliminary sperm injection study with their consent, since in all three cases the zona free hamster egg penetration test was negative and in one couple previous attempts of in vitro fertilization were unsuccessful. Of 22 eggs, recovered from three patients, 9 from each patient 3 were injected with sperm, while the others were inseminated by the standard IVF-protocol. Before manipulating human eggs extended experiments were performed with animals eggs, so decreasing the rate of damage to under 10%. Additionally we optimized the method by using an individual adapted equipment. Manipulation was performed by penetration of the zona pellucida with a 5 to 7 mu thick injection pipet into the perivitilline space so damaging of the egg cytoplasm was avoided. This special technique for sperm injection was not used till now in this indication. From the nine eggs used in this experiment one egg developed a pronucleus and one egg developed to a four-cell stage. We could not achieve a pregnancy.