Intra-Cytoplasmic Sperm Injection (ICSI)
ICSI is a micro manipulation technique that was developed in
Belgium in 1992 and introduced into the United States in 1993. This
technique allows us to inject a single sperm into an egg to achieve
fertilization. Over 2,000 babies have been born with this technique
from men who were otherwise considered hopelessly infertile.
ICSI is an alternative to standard IVF that may be used in case of
severe male factor infertility, using ejaculated, epididymal or
testicular sperm.
As with IVF procedures, ICSI requires ovarian stimulation and egg
harvesting. After the eggs are retrieved, instead of mixing the egg
with the sperm in a culture medium, the embryologist utilizes a thin
glass pipette to strip the eggs from the surrounding cumulus and
corona cells allowing not only precise injection of the oocyte, but
also the assessment of their maturity.
To achieve ICSI fertilization, the following points should be taken
into consideration; selection and immobilization of a viable sperm,
correct positioning of the oocyte prior to injection and the rupture
of the oolemma prior to the release of the sperm into the oocyte.
ICSI procedure:
- A single motile sperm is selected and immobilized, the sperm is
then aspirated tail first into the injection pipette.
- A mature egg is fixed by the holding pipette with the polar body
at the six o'clock position.
- A sperm cell is brought to the tip of the injection pipette.
- The injection pipette punctures the zona pellucida at the three
o'clock position and rupture of the oolemma is done by slight
suction.
- The sperm is delivered into the oocyte with a minimal volume of
medium.
- Our pregnancy rates from sperm injection in younger group of
patients surpass those of regular IVF and the reason is probably
because in most cases where ICSI is done the woman is reproductively
normal and the technique directly overcomes the problem causing the
infertility.
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