INTRA CYTOPLASMIC SPERM INJECTION (ICSI)

Twenty years ago a collaboration between Steptoe, a gynecologyst, and Edwards, a physiologist, resulted in the first baby born by in vitro fertilization with embryo transfer (IVF – ET).

This report represented the biggest advance in infrtility treatment. Since then, IVF became the best treatment for some types of infertility, including infrtility due to tubarian problems, endometriosis, infertility without apparent cause or infertility involving masculine factors..

But soon it became obvious that certain cases of infertility due to severe masculine factors couldn’t be helped by IVF. Main causes for conventional IVF fertilization were: extremely low number of spermatozoa and alterations that impaired their motility and morphology.

Many assisted fertilization procedures based on sperm and egg micromanipulation were developed to solve these problems. Evolution in those methods began with PZD (Partial Zona Dissection), followed by SUZI (Subzonal Insemination – Sperm insemination in the peri-vitelinean space) and finally the ICSI technique (Intra Cytoplasmic Sperm Injection).

The two first methods were developed to overcome the Zona Pellucida barrier, favoring insemination. PZD technique involves the mechanical rupture of the oocyte zona pellucida followed by sperm insemination, which will gain free access to the peri-vitelinean space. By the SUZI method, many mobile spermatozoa (3-20) are freed directly into the peri vitelinean space by an injection pipette. ICSI is more invasive, because only one spermatozoon in immobilized and directly injected into the ooplasm by an injection pipette, crossing not only the zona pellucida but also the oolemma.

In 1992, a group led by Van Steirtghem, reported the first human gestations and births after transference of embryos generated by this new assisted fertilization procedure.

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