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Intra-cytoplasmic sperm injection (ICSI)
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Intra-cytoplasmic sperm injection (ICSI) is a relatively new but well-established procedure first performed in 1992. The procedure was developed to help male factor infertility. The procedure involves injecting a single sperm into the cytoplasm of each egg using a fine glass needle. The first ICSI baby was reported in 1992. The ICSI has largely replaced the two previously developed procedures, PZD (partial zona dissection) and SUZI (subzonal insemination) because it achieves much higher fertilization rates.

For whom ICSI is advised?

There are selected groups of patients to whom intracytoplasmic sperm injection (ICSI) is recommended.

  • Couples who have failed to achieve fertilization or had very poor fertilization following standard IVF treatment.
  • Men with abnormal sperm parameters (e.g. low count, poor motility, high percentage of abnormal forms and high levels of antisperm antibodies in the semen) to allow a reasonable chance of success with standard IVF.
  • Azoospermic (complete absence of sperm in the ejaculate) men who have their sperm surgically retrieved. This could be due to failed vasectomy reversals or congenital absence of both vas deferenses and non-obstructive azoospermia.
  • When frozen sperm is limited in number and quality.

ICSI is generally unsuccessful when used to treat fertilization failure that is primarily due to poor egg quality.

The ICSI procedure

The early stages of ICSI are the same as for standard IVF. The woman takes fertility drugs to stimulate her ovaries with the aim to grow several mature follicles. The eggs are usually collected by vaginal ultrasound scan into a specially prepared culture medium. Once the eggs are collected, they are examined under the microscope to assess their quality. The eggs are then placed in the incubator for a period of time usually between 3-6 hours. Thereafter the eggs are removed from the incubator and the cells that surround the egg are stripped off to assess the maturity of the egg, because ICSI can only be performed on mature eggs. Immature eggs can be kept in the culture medium and injected the following day if they show signs of maturation.

Sperm collection from ejaculate or aspirate from the epididymis (PESA) or testis (TESA or TESE) is prepared using special cultured medium. Sperm preparation may also be obtained from frozen semen sample or testicular tissues.

Once the eggs have been selected, a chosen sperm is rendered immotile, then sucked into the tip of a very fine glass needle and injected directly into the egg. The egg is held in place by gentle suction on the opposite side using a holding pipette. This is a very delicate procedure and involves using a micromanipulator. This process is repeated for each egg. The elastic nature of the egg membrane means that the tiny hole made by the needle closes very quickly. About 5% of the injected eggs may be damage by the procedure.