In normal fertility, a million or more sperm must be mustered to fertilize one egg. In ICSI, the revolutionary new treatment for male factor problems, the sides are more even. A single sperm is injected into an egg. In theory it takes just one sperm for each egg to be fertilized.
ICSI stands for intracytoplasmic sperm injection, a technique perfected by Dr. Andre Van Steirteghem and colleagues at the Center for Reproductive Medicine at University Hospital, Brussels Free University in Belgium. They have had success with men with no motile sperm; they have even had pregnancies with small numbers of sperm, obtained from testicular biopsies or from specimens of the epididymis obtained at microsurgery.
ICSI involves taking a microneedle, puncturing through the outer layers directly into the interior of the egg, and injecting a single sperm inside. First, the semen is specially prepared. The fluid is removed to collect as many motile sperm as possible. Two types of glass micropipettes are needed -- one for holding the egg, one for injecting the sperm. The egg is held in a fixed position, and a single sperm is aspirated into the injection pipette, which is then placed through the zona pellucida (a relatively tough outer coating of the egg) and pushed into the ooplasm (interior of the egg). ICSI is carried out under magnification of 400 power.
After injection of the sperm, the eggs are incubated for 16-18 hours, then examined for possible damage and for evidence that fertilization has occurred. The resulting undamaged embryos can then either be transferred back to the woman's uterus, using standard IVF techniques "EMBRYO IMPLANTATION", or can be frozen for transfer at a later time.
In time, more programs will offer this new technique. Time and experience will also provide more answers about the success and safety of the procedure. Nevertheless, ICSI promises major advances in male infertility if the successes of the pioneering programs can be replicated in clinical practice.