Treatment of male infertility by gamete micromanipulation

Over the past decade, in vitro fertilization (IVF) has become a routine and acceptable tool in the treatment of infertility. However, major limitations in solving certain infertility problems still remain. Male infertility is one area in which only a small fraction of patients have benefited from IVF. Union of male and female gametes, either in vivo or in vitro, requires sperm penetration through the cumulus oophorus and the zona pellucida. Failure of fertilization despite the increased number of spermatozoa introduced into the oocyte's vicinity by IVF, has been shown to be directly related to abnormalities in sperm cell morphology and motility. The improved technology for micromanipulation of gametes has made it possible to circumvent the oocyte barriers to sperm penetration, thereby greatly reducing the number of normal sperm cells needed to achieve fertilization. This paper reviews the three major micromanipulative strategies which have been developed over the past five years, patient selection for the different procedures and the methods of sperm preparation to improve the yield of the applied technique.