INTRACYTOPLASMIC SPERM INJECTION - A POWERFUL TOOL TO OVERCOME FERTILIZATION FAILURE

Objective: To describe the novel micromanipulation technique known as intracytoplasmic sperm injection (ICSI), which has been applied succes sfully to treat male factor infertility, even in patients with severel y impaired sperm characteristics. This paper reviews the historical as pects that led to the development of ICSI in the animal model as well as the current experience in the human. Design: Before using assisted fertilization techniques to enhance fertilization of human gametes, it is imperative that practitioners gain extensive experience in the ani mal model. In addition, criteria for accepting individuals for treatme nt with ICSI are discussed along with other applications of the proced ure in infertile couples who do not benefit from standard IVF. Results : Because ICSI resulted in limited success in animal models, it seemed unlikely that it would be successful in humans. Yet, ICSI now appears to be the most successful and significant innovation developed for de aling with male factor infertility since the emergence of IVF itself. To date, a relatively large group of healthy children have been born f rom this technology and there appears to be no increased incidence of congenital malformations. Conclusions: The consistently high success r ate resulting from the application of ICSI to treat couples with male factor infertility is comparable to the results obtained using standar d IVF techniques performed in nonmale factor couples. This finding ind icates that spermatozoa obtained from subfertile men selected for intr acytoplasmic injection are usually genotypically normal.