ICSI or Intracytoplasmic sperm injection is a laboratory procedure developed to
help infertile couples undergoing assisted reproduction due to male factor
infertility. ICSI, a form of micromanipulation, involves the injection of a single
sperm directly into the cytoplasm of a mature egg (oocyte) using a glass needle
(pipette).
ICSI is used in 90% of fertility centres.
This process increases the likelihood of fertilization when there are abnormalities
in the number, quality, or function of the sperm. ICSI is generally unsuccessful
when used to treat fertilisation failures that are primarily due to poor egg quality.

Before ICSI can be done, mature eggs must be retrieved from the female partner
during a standard IVF cycle. The male partner’s semen sample is prepared in the
lab to isolate as many healthy moving sperm as possible.

Fresh ejaculated spermatozoa and frozen samples (that were surgically retrieved
from epididymis or testis) can be used and results in acceptable clinical
pregnancy rates.

In case no motile sperms are available, an attempt is made to elicit motility thus
verifying viability. Though the clinical, pregnancy and delivery rates in such
patients are halved.

After allowing the eggs to rest for 4-6 hours following their removal, the tight
outer coating of cells (cumulus) is removed from each egg. Only then can we be
sure the egg is mature enough to undergo ICSI.

Immature eggs cannot be injected. However, they can be incubated for a further
4-18 hours and reassessed. If they mature during that time and sperm is still
available, they can undergo delayed injection. Fertilization rates with delayed
injection are not as good as with usual ICSI techniques.

A special instrument is used to hold the egg in place. It is so small you can barely
see the tip with the naked eye. A thinner, sharp, needle-like instrument is used to
pick up a single normal appearing sperm. With great precision, the needle is
inserted through the egg’s outer coating (the zona pellucida) and into the egg
itself. The sperm is slowly injected into the egg, and the needle is removed,
leaving the sperm behind. The injected eggs are placed in an incubator overnight
and checked the next morning for signs of fertilization.

• Very low numbers of motile sperm.
• Severe teratospermia (abnormal sperms).
• Problems with sperm binding to and penetrating the egg.
• Antisperm antibodies thought to be the cause of infertility.
• Prior or repeated fertilization failure with standard IVF methods.
• Frozen sperm limited in number and quality.
• Obstruction of the male reproductive tract not amenable to repair. Sperm may
  then be obtained from the epididymis by a procedure called microsurgical
  epididymal sperm aspiration (MESA), or from the testes by testicular sperm
  aspiration (TESA).

Fertilization occurs in 85% of injected eggs. The ICSI process may damage a
small percentage of eggs. The fertilized egg may fail to divide, or the embryo
may arrest at an early stage of development. Approximately 40% of all ICSI
cycles performed result in a live birth, which is comparable to rates seen with
traditional IVF. Younger patients may achieve even more favourable results.
Factors such as poor egg quality and advanced maternal age may result in lower
rates of success.

ICSI does not increase the incidence of multiple gestations as compared to
standard IVF. To date, there is no convincing evidence that the incidence of birth
defects is any different with ICSI or IVF as compared to those children born to
other parents of similar age and health. This is an area of ongoing investigation.
Because some causes of male infertility are familial and are related to genetic
problems, male offspring might have reproductive problems as adults. Despite
these concerns, ICSI is a major advance in the treatment of severe infertility