Treating Infertility using ICSI or Microinjection

Microinjection or intracytoplasmic sperm injection (ICSI) uses micromanipulation technology to treat infertile males. A single sperm is injected into the middle of the egg (cytoplasm) for fertilisation. The main advantage of this treatment is that low sperm count or abnormal sperms is not a problem. Only live sperms are needed to achieve fertilisation. This avoids the need of your partner to require a donor sperm to fertilise your egg. Your partner will also be happy to father his own baby. Thus, ICSI is one of the most common approaches towards treating male infertility.

ICSI is similar to IVF except for the fertilisation stage. In an ICSI, the number of sperms must be equal to the number of eggs to achieve fertilisation. The same process must be repeated for fertilisation of each egg and sperm.

Fertility drugs are given to the wife to produce multiple eggs. These eggs are then removed using vaginal ultrasound. The cluster of cells surrounding the eggs are also removed. The husband's sperms are collected through masturbation. Sometimes, many ejaculates are needed if the male has low sperm count. Extra sperms may be frozen for later use and thawed when needed. If the man has no sperms at all, sperm harvesting techniques are used. If his ducts are blocked or in the absence of a duct, his sperms are sucked out from the epididymis by making a hole with a fine needle. However, locating sperms in males with testicular failure can be challenging and time consuming.

Once the egg and sperm are ready, the sperm is injected into the egg in a laboratory. Special micromanipulators are used to achieve this precision. Both the egg and sperm are manipulated using holding and injection pipettes with very fine tubes. A drop of viscous polyvinyl pyrrolidone (PVP) solution is poured on the sperm to slow down its movement. Once the movement slows down, the tail of the sperm is crushed or bent to make it immobile. This is done so that the sperm does not move about after being injected into the egg. This immobile sperm is then collected by suction into the injection pipette.

Suction is applied to the shell of the egg using a holding pipette. This is done to hold the egg in place. The sperm is then injected directly into the cytoplasm by blowing the sperm gently out of the injection pipette using the micromanipulator. The zona and the outer membrane of the egg must be breached for this injection. After injecting the sperm, the pipette is withdrawn. The egg will automatically close and assume its original shape in a minute.

The injected egg is kept under observation for fertilisation in a carbon dioxide incubator for about 14 hours. If fertilisation has taken place, the embryos are transferred into the wife's uterus after about a couple of days.

The average success rate of fertilisation is about 50 to 80%. A main advantage of ICSI is that it does not increase the chances of multiple pregnancies. Also, no surgery is needed for an ICSI.