Conventional IVF (link)  is not an answer for couples with severe male factor infertility.  This includes those with extremely low sperm counts, impaired mortality and / or low percentage of normal sperms. ICSI is an invasive technique where in a sperm is directly injected into the egg or oocyte, thereby overcoming the barrier of the zone pellucida or covering of the egg. ICSI is also indicated in those with failed conventional IVF; whose male partner had a normal semen analyses. It is a safe simple procedure, performed world wide with good success rates. 

Preliminaries

For ICSI sperms can be obtained after ejaculation.  In case it is not possible to obtain sperms by this method, then sperms can be recovered from the testes or epididymis by means of a small surgical procedure.  These procedures can be carried out under local or general anesthesia, and are as follows. 

PESA

Percutaneous epididymal sperm aspiration.  A fine needle is inserted into the epididymis at the upper area of the testes and sperms are obtained by gentle suction.

TESE

Testicular sperm extraction.  A fine needle is inserted into the testes and samples of tissue are obtained by gentle suction in order to retrieve enough sperms.  If too few sperms are obtained a biopsy (tissue sample) is taken through a small incision.  The incision is closed with 2-3 stitches. The procedure is carried out under local anesthesia.

After care: 

There will be a little bruising and tenderness of the scrotum for 24-48 hours after PESA or TESE.  The stitches dissolve in 10-14 days.  The patient should maintain scrotal hygiene as routine. Most patients can resume full activity within 2-3 days.

Sperms recovered by any of the above procedures can be frozen & used in later cycles, in case the ongoing one fails.  Hence repeated surgery is avoided. The woman goes through the stages of ovarian stimulation & oocyte retrieval as in conventional IVF.

Preparation of the gametes (sperm & egg)

The oocytes (egg) are freed of their surrounding structure called the cumulus and corona cells.  The oocytes are then examined under a special microscope to assess their maturity.  Those that have reached the right stage of maturity (metaphase – II oocytes) are selected for the ICSI procedure.

Sperms obtained by either one of the above methods are processed or washed.  The purpose is to clear out tissue debris and cells that may block the tube or pipette used for injection.  This enables the selection of normal sperm/s, which is then used.

The procedure

The sperm & the oocyte are handled at temperaures of 37 degree C (same as that of the body). The procedure is carried out in a dish under a special microscope. 

ICSI procedure uses high precision equipment for injecting the sperm into the egg. No damage to the sperm or the egg occurs during the procedure.  The egg is then incubated under standard conditions.  It is examined 16-18 hrs later to ensure fertilization, which is evident by the presence of certain features in the egg. The same procedure can be repeated out on other oocytes i.e. one sperm to one egg. The fertilization rate after ICSI using ejaculated sperms is around 60-70%. With sperms sourced from other procedures, it is around 50%. 

Post ICSI

After another 24 hrs the division of the fertilized egg/s are evaluated.  The resulting embryos are graded with respect to quality.  The best quality embryos are chosen for transfer. This procedure is the same as for conventional IVF.  Further follow up is the same as that of conventional IVF.

Pregnancy & delivery are expected to proceed as normal.  No complications in terms of abortions, congenital abnormalities or pregnancy complications result per se to the ICSI procedure.

Future prospects

Currently the sperm is chosen based on its external appearance. Very soon in a technique termed preimplantation genetic diagnosis (PGD), the chosen sperm is going to be studied in terms of its chromosomal make-up. This will help circumvent the small but possible risk of transmission of chromosomal abnormalities, which is a possibility when a sperm is chosen at random.  After all one must remember that in a natural cycle of conception, nature has its own parameters of selection of the best sperm.  Among a million sperms only one sperm impregnates the egg.  It is wise to postulate that this selection will include choosing the best genetic make-up as well.  Till such time that PGD becomes mandatory prior to ICSI, it is assuring to note that countless ICSI procedures have been carried out worldwide. A very large majority of them have resulted in normal offsprings.