ICSI
Intra- cytoplasmic sperm injection (ICSI) is a technique for the treatment of extreme male infertility in which sperm are injected directly into the body (cytoplasm) of the egg. It is especially useful for patients where the male partner has a very low sperm count (oligozoospermia), poor sperm motility (asthenozoospermia) or too many abnormal sperms (teratozoospermia). Also, in men with obstructive or non-obstructive azoospermia (zero sperm counts), sperm can be directly retrieved from the testis and used for ICSI, thus helping him to have his own biological child.
When is ICSI Used?
If there are even a small number of sperm in the ejaculate, (or if sperm are affected severely by antisperm antibodies during their maturation process) sperm can be taken from a semen sample for ICSI. If there are no sperm in the ejaculate, due to an obstruction or to very low sperm production, sperm can now be surgically retrieved directly from the testes or the epididymis (TESE, PESA). Because it is the genetic information carried in the head of the sperm that needs to get into the egg, immature sperm whose tails have not fully developed are adequate for use in ICSI. ICSI is also sometimes used if there is an apparent problem with fertilization in an IVF cycle. In summary, ICSI helps bypass almost all sperm problems in infertile men such as azoospermia (zero sperm count), oligozoospermia (low sperm counts), asthenozoospermia (poor sperm motility), teratozoospermia (too many abnormal sperms) and also patients of retrograde ejaculation or anejaculation (where electroejaculation and IUI have failed to give a pregnancy).
How is it done?
This procedure is very specialized, and requires a great deal of skill on the part of the scientist. All the procedures require the use of special microscopes and micromanipulation equipment. To put it in perspective, an egg is approximately one-tenth of a millimetre across! The egg is gently held with a suction pipette (on the left in the picture below) while a sperm is picked up with a microinjection needle, and deposited in the cytoplasm of the egg. By doing this, several barriers to the sperm have been removed, and fertilization usually follows. The day after injection, we can tell whether fertilization has taken place if there are two small spheres (pronuclei) visible in the egg. If fertilization is successful, the pre-embryo (zygote) is allowed to divide several times in culture medium in the laboratory, before it is transferred to the uterus or fallopian tube. Any "spare" good embryos resulting from the procedure can be frozen for more attempts later.
To summarize the ICSI process:
The mature egg is held with a specialized holding pipette.
A very delicate, sharp and hollow needle is used to immobilize and pick up a single sperm.
This needle is then carefully inserted through the zona (shell of egg) and in to the cytoplasm of the egg.
The sperm is injected in to the cytoplasm and the needle carefully removed. The eggs are checked the next morning for evidence of normal fertilization
What is the success rate like?
ICSI has similar success rate to IVF (about 50% of embryo transfer procedures produce a clinical pregnancy). IVF has a slightly higher pregnancy (about 54%), although this might be explained by the problems inherent in some cases to the sperm generally used in ICSI procedures. Frozen embryo transfers after ICSI also have a similar success rate to those after IVF (about 29%). These results do vary with female age, with a substantial fall in pregnancy rates in women over the age of 38.
What about the babies born by ICSI?
At the current moment, available research suggests that ICSI and IVF born children are normal. There is no increased risk of any anomalies or developmental delays in offspring born from these techniques. Stray reports which appear in the press may be related to children born from these techniques in the older age group which is at a higher risk for such anomalies (age related and not technique related)
