Intracytoplasmic Sperm Injection (ICSI) involves injecting a single spermatozoid directly into the egg cell cytoplasm. The procedure is conducted with a so called inverted microscope at magnifications of 200 to 400 times, using pipettes which are 20 times thinner than a human hair (for holding) and 60 times thinner than a hair (for injecting).
During the procedure, the egg cells are freed from surrounding cumulus cells with the use of the hyaluronidase enzyme. There follows the capture of a suitable spermatozoid in an injection pipette, fixing the egg cell with a holding pipette, and injecting the spermatozoid into the egg cell cytoplasm.
Once injected, the egg cell is returned to the incubator, to be assessed 16 to 18 hours later for fertilisation.
Indications for ICSI:
- Oligozoospermia (under 20 million/ml);
- Asthenozoospermia (fewer than 30 per cent moving spermatozoa);
- Teratozoospermia (fewer than 5 per cent normal shapes according to strict Kruger’s criteria);
- Where poor spermatozoal vitality is diagnosed;
- In patients who have experienced fertilisation failures in prior IVF cycles;
- In patients who have experienced several unsuccessful IVF cycles.
Indications for ICSI broadened in recent years, with the method also applied with women in advanced reproductive age, with endometriosis-based subfertility, immunological factors, and infertility for unclear reasons.
The ICSI methodology described above has led to modified Azoospermia treatments:
- MESA (spermatozoal epididymal aspiration);
- TESA (spermatozoal testicular aspiration);
- TESE (spermatozoal testicular extraction).