The Intracytoplasmic Sperm Injection (ICSI), consists in the introduction of a single spermatozoid inside a mature egg to achieved fecundation. Undoubtedly, is the assisted reproduction technique (ART) most use and it meant a revolution in the early 90s, as it came to successfully solve the majority of the sterility problems cause by the masculine factor.
Due to its high and constant exit rates to achieved fertilization, the ICSI technique has not substantially changed since the beginning. The necessary equipment consists of an inverted microscope, with a specific optic (Hoffman) and a heated plate (37¼). Micro-handles are attached to this microscope allowing us to make three-dimension movements with the micro-pipettes that hold the egg and contain the spermatozoid. The sperm motility as well as the experience of the embryologist that performs the technique are the two most important factors to guarantee the effectiveness of the technique.
The sperm selection techniques previous to preforming the ICSI have evolved in the last few years allowing us to carry out a more specific selection. Nowadays we can carry out a morphological evaluation choosing the spermazoid that are going to be microinjected with special optics that allow its vision with over 6000 magnifications (IMSI). It can also be carried out what is called Òphysiological ICSIÓ where hyaluronic acid is used in the micro-injection plate or in the culture medium (ÒSperm SlowÓ) to select the mature spermatozoids which, a priori, present a reduction in chromosomal imbalance. However, recent studies have not shown the supremacy of those methods and are still in an experimental stage.
The use of annexin columns type MACS previous to the ICSI technique also allow us to select pre-apoptic spermatozoids, which will go into a programmed cellular death and could not give place to ongoing embryos. These columns are also used in cases where an excessive spermatic DNA fragmentation, which is related to fertilization failure cases and embryo blockage.
The indications to carry out an ICSI technique has to be supported in a thorough fertility study to the couple and could be the following:
1. Masculine sterility:
2. Female sterility:
3. Other causes:
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