What Is ICSI And When Might An ICSI Procedure Be Used
ICSI (pronounced ik see) Intra-cytoplasmic sperm injection, is an in vitro fertilization (IVF) technique. As discussed elsewhere in this web-site the process of IVF involves fertilizing the female ovum with sperm under laboratory conditions. The zygote (fertilized egg) is then placed in the woman’s uterus by artificial insemination and develops into an embryo. ICSI is a specialised IVF procedure that is used when either sperm count or motility is abnormally low.
Although first performed in 1992 ICSI has only recently become a well established procedure. During an ICSI procedure a single healthy sperm is injected into the cytoplasm of an individual ovum using an ultra fine glass needle. ICSI is recommended for those couples for whom a standard course of IVF has failed. ICSI rarely has any positive effect when used to try and fertilize an ovum of poor quality. It is seen as a treatment to fertilize ova with poor quality spermatozoa.
Typical scenarios for ICSI to be considered are:
~ If a man has a sperm count considerably below the usual marque for male fertility of 20,000,000 sperm per milliliter of ejaculate. ICSI can now be used with a sperm count as low as 1 or 2. (However, this produces a challenge to the medical technician performing the in vitro fertilization as they may have difficulty finding them.)
~ If a man has an abnormally low sperm motility, providing there is some motility (purposeful movement by the sperm) the ICSI technique can by used.
~ If a man has an abnormally high incidence of antisperm antibodies. This would result in a form of immunological infertility; his body treats the sperm as if it were a bacteria or virus and sets up anti-bodies to destroy the sperm.
~ If the man produces sperm but it is absent from his ejaculate. This is called zoosperm. This can arise after a failed vasectomy reversal or if the vans deferens is blocked. In such cases the sperm is surgically removed from the testes prior to the ICSI treatment.
~ In rare cases it has also been used in conjunction with the use of frozen sperm, if the amount and/or quality of those sperm are poor.
ICSI still requires the woman to take a course of fertility drugs prior to the treatment in order to ensure that her ovaries are stimulated to produce ova that can be extracted for the procedure. The ICSI procedure must be performed on mature ova only. Following extraction of the ova from the woman they are incubated for 3 to 6 hours. If still not matured they can be left in the incubator until the next day. Having selected the ova to be used, a single sperm is rendered immotile by having its tail ‘shaken’ off by the glass needle. The sperm head is then pipetted into the glass needle which, in turn, then injects the single sperm into an ovum. During this the ovum is held steady by gentle suction from another pipette. This is, of course, a very delicate and gentle procedure involving the use of a micromanipulator. The elastic nature of the ovum’s membrane means the minute hole created by the glass needle quickly closes. The process is then repeated for as many ovum or sperm as are available.
Inevitably, as this is such a delicate procedure, about 5% of injected ova are damaged by it. There is also about a 5% risk of complete failure using this treatment. However, around 65% of the ICSI procedures carried out result in zygote (fertilized ovum) being produced and 80% of those zygotes go on to successfully form an embryo. The live birth rate following a successful embryo transfer arising from ICSI is around 25%. ICSI is a highly complex and skilled procedure and success rates can vary according to the skill and experience of the practitioners.