Subzonal insemination and zona breaching techniques for assisting conception in vitro.

The following comments can be made with regard to zona breaching procedures (PZD) and SUZI. First and foremost, it is important to establish that fertilization cannot occur with microdrop IVF or conventional IVF before proceeding with microassisted fertilization technology. PZD increases the rate of polyspermy, and this is significantly higher than when utilizing SUZI. SUZI increases the incidence of implantation in cases exhibiting severe teratozoospermia. SUZI increases the fertilization rate per patient and per oocyte in cases where IVF has previously failed on more than one occasion. SUZI increases the incidence of fertilization when very few motile sperm are available, and there is an increase in the incidence of cytoplasmic fragmentation with SUZI, which might be alleviated by improving methods of penetrating the zona pellucida, for example by using the Sonic Sword or utilizing a thinner, sharper injection needle alone or in addition to increasing the perivitelline space by dehydrating the oocyte (Yang et al, 1988). Morphology is an important parameter in predicting the outcome of IVF and therefore in guiding patients on the relevance of microinjection technology.