MICROMANIPULATION

INTRACYTOPLASMIC SPERM INJECTION (ICSI)

INTRODUCTION

The ability of the urologist to address problems of severe male factor infertility has been revolutionized with the introduction of intracytoplasmic sperm injection (ICSI). 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. Although the first success using this technique was reported as recently as 1992, ICSI is now being performed by most major in vitro fertilization (IVF) centers in the United States.

BACKGROUND

The origins of gamete micromanipulation and ICSI, in particular, can be traced to the late 1970's when initial attempts at IVF culminated in 1979 in the first successful IVF "test tube baby." In standard IVF, human oocytes harvested from hyperstimulated ovaries are incubated in a culture dish with sperm. Couples with severe male factor infertility were frequently not candidates for IVF or had poor results because approximately 150,000 motile sperm per oocyte are required.

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 (Fig 1)

Figure 1. Intracytoplasmic sperm injection.

INDICATIONS FOR ICSI

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.

Immunologic 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. Because of comparable fertilization rates with fresh sperm, the>

Transfer interrupted!

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. Our experience with 12 ICSI-IVF cycles demonstrated a pregnancy rate of 45.5%.

PROCEDURE

At Baylor College of Medicine, ICSI is performed by the Scott Department of Urology after a complete male evaluation. Oocyte harvesting, embryo incubation, and embryo transfer are performed by collaborating reproductive endocrinology groups.

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 Percoll 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.

DETERMINANTS OF SUCCESS

With even the most severe of male factor sperm defects treatable using ICSI, female factors such as age and oocyte quality are being examined more closely. While the severity of semen abnormalities demonstrate little correlation with ICSI results, egg number and egg quality are now the main determinants of success. Poorer results with ICSI have been observed in women 40 years of age or older, likely due to poorer oocyte quality and diminished oocyte retrieval after ovarian hyperstimulation. Despite concerns with the possibility of an increased risk of birth defects from ICSI, no convincing data have been demonstrated thus far.

FEES

FEES FOR ICSI ARE SEPARATE FROM STANDARD IVF. ICSI IS PERFORMED BY THE LABORATORY FOR MALE REPRODUCTIVE RESEARCH AND TESTING AT THE SCOTT DEPARTMENT OF UROLOGY, BAYLOR COLLEGE OF MEDICINE.

ALL CHECKS SHOULD BE MADE PAYABLE TO LABORATORY FOR MALE REPRODUCTIVE RESEARCH AND TESTING, BAYLOR COLLEGE OF MEDICINE. WE ALSO ACCEPT VISA OR MASTERCARD FOR PAYMENT (SCURLOCK TOWER, SUITE 2100, 6560 FANNIN).

1. ROUTINE ICSI: Routine ICSI is micromanipulation that is planned prior to the actual day of egg extraction and insemination. You will be counseled by your gynecologist regarding the expected need to perform ICSI as an aid to better ensure fertilization. You must go to the Special Procedures Laboratory to meet with Dr. Lipshultz's nurse, who will ask you to read a routine informed consent specific for this procedure and to have this signed and returned 1 week prior to the day of the egg removal. A fee for gamete micromanipulation will be required in advance. TOTAL: $1,250

1. DAY 2 ICSI: In some patients, when the eggs are removed they are "immature" at the time of extraction. It will usually take another 24 hours until this particular set of eggs can be micromanipulated. Hence, the micromanipulation procedure will be done on the mature eggs on the day of extraction and on the second day (the day following extraction) on those eggs that have matured subsequent to their original removal from the ovary. However, only a single fee of $1,250 (as described above) will be expected prior to the day of insemination.

1. DAY 2 ICSI FOLLOWING FAILED IVF : In some instances, lack of fertilization may occur that was not previously expected. For these couples, following the laboratory report that no fertilizations or only few fertilizations have occurred, you may be asked if you would like the remaining unfertilized eggs (if they are still healthy) micromanipulated with ICSI. This is termed "rescue" ICSI. A signed informed consent will be required prior to micromanipulation. Since this was not planned in advance, you will not have had a chance to pay for this procedure. Consequently, payment will be expected on the day of the micromanipulation or the day following this ($1,250). Again, instructions for payment are the same as those listed above.

If there are any questions concerning any of the above payment procedures, please direct them to the laboratory secretary, Ms. Michelle Hunter (713-798-5160). Certainly, a good source of additional information is the IVF coordinator in your particular program or the gynecologist who is directing your in vitro cycle.

Again, if there are any questions following your reading this descriptive pamphlet, please do not hesitate to contact Dr. Dolores Lamb (713-798-6266), the Laboratory Director, or Dr. Larry Lipshultz (713-798-6163).