Intracytoplasmic sperm injection (ICSI) involves the injection of a single sperm directly into the cytoplasm of a mature egg. ICSI is a treatment method that is primarily used when traditional IVF cycles fail or in cases associated with low sperm count.

In What Cases is ICSI Recommended?

1. In the fertility treatment associated with male factor infertility
2. Failure in fertilization with traditional IVF cycle
3. In the fertilization of frozen and thawed eggs
4. In the fertilization of mature egg cells in the external environment
5. In cases where Preimplantation Genetic Testing is considered
6. In the treatment of selected types of female infertility, such as some structural anomalies in the ovum and abnormalities of the membrane surrounding the ovum called zona pellucida

In couples without one of the reasons listed above, the use of ICSI is less effective than traditional IVF and is not recommended.

Successive Stages for ICSI
Despite the sperm imitates the natural process to fertilize the egg in the lab environment in traditional IVF, in ICSI, the embryologist injects a single living and morphologically normal spermatozoon into the cytoplasm of the egg with the help of a micropipette.

1. Cleaning of cumulus and corona cells for ICSI:
   After a minimum incubation period of 2 hours following the ovum pick-up (OPU) process, the cumulus and corona cells surrounding the egg cell are cleaned.
2. Microinjection procedure (ICSI):
   An immobilized spermatozoon is gently injected close to the center of the oolema by slowly passing through the protective coat of the egg called zona pellucida via a fine needle, called a micropipette.Lately, Piezo-driven pipettes are widely used for Intracytoplasmic Sperm Injection. These injectors are preferred since they cause less egg damage as they penetrate the zona pellucida using ultrasonic shear force instead of piercing force.High-quality optical instruments, high precision micromanipulators, and hydraulically operated microinjector injection systems working with air or oil are needed to prevent damage to female egg cells.Laser-assisted ICSI is an innovative approach used in patients with poor ICSI results and limited metaphase II oocytes. If the ICSI procedure is not done carefully, the nuclear material of the egg cell may be damaged.

Success Rates
Fertilization rates after ICSI are approximately 50-80%. Poor egg quality or nonviable sperm are usually the basic cause of unfertilized eggs. In 8-20% of the cases, fertilization does not occur as a result of egg damage caused by the ICSI procedure. ICSI appears to increase the risk of monochromic twin placentation, especially when combined with blastocyst transfer. However, there is not enough data on this issue yet.

Intracytoplasmic morphologically selected sperm injection (IMSI):
IMSI is a variation of ICSI that uses a higher-powered microscope to select sperm. This allows embryologists to look at the sperm in greater detail including the nucleus which contains the sperm’s genetic material. Some studies suggest that this technique helps select higher quality sperm resulting in higher pregnancy and less miscarriage rates compared to traditional ICSI. However, data supporting this claim is limited. Therefore, IMSI is not currently considered as an alternative method to replace the routine use of ICSI.