Intra-Cytoplasmic Sperm Injection ICSI
The ICSI procedure entails the deposition of a single sperm into the main body of the egg (cytoplasm), thus bypassing the egg's outer layers (zona pellucida). The whole procedure is performed in the lab by the embryologists using special equipment, for egg and sperm manipulation, under the control of high-powered microscopes.
Fertilization failure in IVF is particularly common where there are grossly abnormal semen parameters or where the number of active spermatozoa is insufficient. Gamete micromanipulation is the only way to overcome this problem and offer assistance to couples who previously had to rely on the use of donor sperm.
ICSI is usually carried out in cases of severe male infertility (low number of active sperm cells or increased number of abnormal shapes) and is also suggested in couples who have undergone multiple conventional IVF cycles with low fertilization rates.
Further indications for the performance of this procedure are:
- retrieval of a low number of oocytes
- the existence of sperm with no acrosome unable to penetrate the oocyte
- oocytes with thick zona pellucida
Oocyte Spindle detection during ICSI
Oocytes after ovulation are at metaphase II, the stage in which the meiotic spindle is formed. The meiotic spindle plays an important role in the oocyte during chromosome alignment and separation at meiosis.
It has been reported that spindle abnormalities in oocytes during meiosis contribute to:
- aneuploidy in embryos after fertilization
- poor embryo development
- spontaneous abortion
- inherited diseases.
The spindle is a fragile mechanism that must be avoided during sperm injection. Studies have shown that the damage to the metaphase spindle reduces fertilization and embryo development.
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Microfertilization - IMSI
Intracytoplasmic Morphologically Selected Sperm injection into the Ovum (IMSI)
In assisted insemination technology, many factors affect the possibility of fertilizing the ova and the growth of fetuses. The genetic material (DNA) integrity of the spermatozoa is one of the most important factors.
The IMSI method is a method of spermatozoa choice based on high-resolution microscopy that allows the enlargement (x 6000) of the spermatozoa and consequently the detailed depiction of their head and the evaluation of the «vacuoles» that possibly exist. In this way, the preselection of spermatozoa is performed before the fertilization using ICSI, and only the best spermatozoa are used.
IMSI (intracytoplasmic morphologically selected sperm injection into the ovum) minimizes the father’s contribution to IVF's failure. The better spermatozoa are thereby used in the ova's fertilization, using ICSI- microfertilization. According to international research, using IMSI technology demonstrates clear benefits in achieving clinical pregnancy (Bartoov et al., 2003, Berkovits et al., 2005, Hazout et al., 2006).