Intracytoplasmic sperm injection is a micromanipulation technique in which fertilization is brought about by the injection of a single spermatozoon into an unfertilized egg (or oocyte, - see illustration 7). ICSI is performed with eggs obtained after ovulation stimulation as for IVF, and has greatly improved the treatment of male infertility as a result of severe oligozoospermia (abnormally low sperm count). The pregnancy rate with this procedure varies between 25 – 35 %.

Intracytoplasmic sperm injection (ICSI) has revolutionized the treatment of male infertility. Men previously considered untreatable with conditions such as congenital bilateral absence of the vas deferens and very low sperm counts (oligospermia) are now potentially able to initiate a pregnancy with ICSI.

Interest in the initial types of micromanipulation procedures, such as zona drilling and partial zona dissection (PZD), evolved because of the disappointing results of standard IVF for the severe male factor patient. In these procedures, a physical opening is created in the zona pellucida by using chemical "drilling" or by making a microscopic mechanical incision. Subzonal insertion of sperm (SUZI), the microinjection of spermatozoa into the perivitelline space (between the zona pellucida and the plasma membrane), gained popularity for severe male factor infertility because typically only 3 to 4 sperm were inserted per oocyte. The high rate of polyspermy, a lethal condition involving the entrance of more than 1 sperm into the egg and a problem with PZD and SUZI, was finally overcome with ICSI, which requires the injection of only a single sperm per egg. Because of higher clinical pregnancy rates and broader applicability for severe male factor infertility, ICSI has now replaced PZD and SUZI

ICSI requires only one spermatozoon for each egg and because of this, its indications have been expanded to include nearly all men with serious infertility, including many who would previously have been considered hopeless cases. Provided the spermatozoa are viable, even sperm dysfunction may be overcome, since more than 50% of eggs fertilize normally regardless of the sperm quality. Obstructive azoospermia (absence of sperm in the ejaculate) can also be treated by retrieval of spermatozoa directly from the epididymis or testes and even immature spermatozoa have been used to produce embryos.

Schematic Illustration of Intracytoplasmic sperm injection (ICSI)

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Casessin, which ICSI may be recommended

  • Severe oligospermia - Very low numbers of motile sperm with normal appearance
  • Severe asthenospermia (decreased sperm motility)
  • Abnormal sperm morphology (teratospermia)
  • Obstructive azoospermia requiring MESA
  • Congenital bilateral absence of the vas deferens
  • Failed vasectomy reversal
  • Acquired epididymal or vasal obstruction
  • Abnormal sperm function
  • Defective acrosome reaction or capacitation
  • • Abnormal sperm penetration - Problems with sperm binding to and penetrating the egg
  • Antisperm antibodies (immune or protective proteins which attack and destroy sperm) of sufficient quality to prevent fertilization
  • Prior fertilization failure with standard IVF culture and fertilization methods
  • Absence of sperm in the seminal fluid
  • Day # 2 ICSI after failed IVF ("rescue" ICSI)

Advantages of ICSI

Most effective procedure for male infertility
Overcomes some sperm quality problems

Disadvantages of ICSI

Possibility of transmitting infertility to offspring
Technically demanding
Price / costs

Rescue ICSI

"Rescue" ICSI involves microinjection of oocytes that have unexpectedly failed to fertilize after conventional IVF. ICSI can be performed when few or no oocytes are fertilized after one day and is preferable due to the poor results of second-day routine IVF insemination.

After Previously Failed IVF

The failure to fertilize in a previous cycle of IVF is an indication for ICSI because of probable impaired sperm penetrating capabilities. Successful ongoing ICSI pregnancies have been reported in large series of patients who have failed previous IVF or had too few spermatozoa for conventional IVF.

Immunological Infertility

When high quantities of antisperm antibodies are present in the male, treatment with corticosteroid therapy, sperm washing, and routine IVF has been frustrating and often unsuccessful. Consequently, ICSI is now recommended as the primary choice of treatment in this patient population. ICSI appears to bypass the problems of impaired sperm binding and penetration of the zona pellucida, resulting in higher fertilization and pregnancy rates.

Teratospermia (Abnormal Sperm Shape - Morphology)

The poor results with conventional IVF in the presence of teratospermia have been described using the Kruger strict morphology criteria, especially when fewer than 4% normal sperm forms are found. Although the indications for ICSI with teratospermia are not fully defined, ICSI should be the treatment of choice after failed IVF, despite using high sperm concentrations.

Severe Oligoasthenospermia and Testicular Failure

The best results with ICSI fertilization rates are reported using ejaculated sperm, even in the presence of severe defects in sperm density, motility, and/or morphology. While good results are now observed using testicular and epididymal sperm, ejaculated sperm should be used when this option exists. In testicular failure with no sperm in the ejaculate, testicular sperm extraction (TESE) combined with ICSI has resulted in successful ongoing pregnancies.

Obstructive Azoospermia: Congenital Absence of the Vas Deferens, Failed Vasectomy Reversal, and Acquired Epididymal Occlusion

The results of microepididymal sperm aspiration (MESA) combined with IVF and ICSI for obstructive azoospermia are far superior to conventional IVF. ICSI is clearly the treatment choice for men with surgically noncorrectable vasoepididymal lesions. Successful percutaneous epididymal sperm aspiration (PESA) has been described, but the blind and potentially damaging nature of the procedure discourage its routine use.

The cryopreservation of sperm in men undergoing MESA or vasectomy reversal should be strongly considered given the success of using thawed spermatozoa for ICSI. TESE with ICSI has been used for azoospermic men when no sperm can be recovered from the epididymis, most often with complete absence of the epididymis or a massively scarred epididymis.

Abnormal Sperm Function

Because of impaired sperm function and poor fertilization rates after electroejaculation in anejaculatory patients (e.g., spinal cord injury) using intrauterine insemination or standard IVF, ICSI may have a prominent role in this group of patients.


ICSI begins with oocyte retrieval using transvaginal ultrasound-guided puncture at the time of optimal follicular development following appropriate hormonal stimulation. After a brief incubation, mature oocytes are candidates for ICSI. Sperm preparation typically uses a sperm wash, swim-up procedure, or density gradient centrifugation, depending on the source of the specimen and the sperm characteristics. Sperm sources include fresh and frozen routine ejaculates, microepididymal sperm aspirates, and testis biopsy.

Micromanipulation procedures are performed using an inverted phase-contrast microscope at 400X. With the sperm and oocytes in the Petri dish, a single motile sperm with grossly normal morphology is aspirated tail-first into the injection pipette. The micropipette is pushed through the zona pellucida until the ooplasm is entered. The needle is withdrawn after introduction of the spermatozoa into the oocyte.

After 16 to 18 hours of incubation, the oocytes are examined for the presence of normal fertilization. Embryo transfer can be performed from 1 to 3 days after oocyte harvest. Depending on maternal age and the reproductive endocrinologist's preferences, generally 3 to 6 of the morphologically best embryos are transferred to the uterus, while the remaining embryos are frozen.

ICSI procedure

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Development of Embryo

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Dr. Patil’s Fertility and Endoscopy Clinic

Center for Assisted Reproductive Technology, Endoscopic Surgery and Andrology

No 1, Uma Admirality, First Floor, Bannerghatta Road, Bangalore - 560029
Ph: 080 - 41201357, 41462419 Mobile: 9945221622

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