ICSI (intracytoplasmic sperm injection) has revolutionized IVF because it
has allowed us to offer treatment to men for whom no treatment was available.
Not only will it help couples in whom the male has just a few, barely swimming
sperm in the ejaculate, but thanks to advanced techniques for aspirating
sperm from the ductal system and techniques to harvest sperm from testicular
biopsies, it can also aid men who ejaculate no sperm. These sperm-harvesting
techniques include MESA (microsurgical epididymal sperm aspiration) and PESA (percutaneous epididymal sperm aspiration), an office procedure where
sperm can be obtained by passing a tiny needle through the skin into the
epididymis. Testicular sperm extraction (TESE) is also an office procedure,
now sometimes done with a large biopsy needle under local anesthesia, rather
than being done as a full surgical biopsy, but sperm are not as reliably
obtained.
This new micromanipulation treatment, which was developed in Belgium and
introduced into the United States in 1993, evolved from previous attempts
at micromanipulation such as PZD (partial zona dissection) and SUZI (subzonal
insertion), which did not enjoy the success that ICSI has attained.
The IVF cycle is conducted exactly in the manner described above with a
very few exceptions. After the eggs are retrieved, instead of mixing the
sperm with the egg, the embryologist utilizes a thin glass pipette to immobilize
the sperm, sucks it up into the pipette, and then injects it directly into
the egg’s cytoplasm. Since the egg is the size of a pinpoint, it is
a sophisticated technique requiring a high-powered microscope, tiny glass
pipettes, and instruments that translate hand movements into extremely fine
movements of the pipettes.
In the 2001
SART/CDC report, 50% of ART cases involved ICSI. The success rate for
IVF with ICSI is about the same as for IVF, indicating that the manipulation
has very little effect on the egg. However, since the female partners
of these men are often reproductively normal, there may be some small
adverse effect, also reflected in reports of slightly reduced embryo quality
with ICSI. Most data indicates similar rates of congenital abnormalities
with the general population and IVF without ICSI, although some reports
suggest a minor increase of chromosomal anomalies, many of which are related
to the man’s genetics or his sperm, rather than the procedure itself.
Because of these concerns, prenatal genetic testing with a fetal karyotype
is suggested for ICSI pregnancies. Recently, there have been concerns
about a higher rate of some very rare abnormalities which may be associated
with IVF and ICSI, specifically Beckwith-Wiedemann syndrome which includes
kidney problems, low blood sugar and an increased risk of childhood tumors.
In a proportion
of men (10 to 20 percent) with very low or absent sperm in the ejaculate,
the man may have a chromosome defect or a genetic defect not visible on
routine chromosome analysis (Y chromosome microdeletion) that could pass
on a similar problem with infertility to male offspring. Rarely, such
a chromosome defect could cause a serious abnormality in the offspring.
Therefore we suggest a pre-cycle karyotype for men with fewer than 5-10
million sperm per ml in the ejaculate. In men with congenital absence
of the vas deferens, one can assume the male is a carrier for cystic fibrosis
(CF). Since such men can have a mutation not screened for in the standard
CF panel, it is recommended to test the female partner. If she is a carrier,
the couple could elect to have their embryos tested for CF by testing
a sample of amniotic fluid and aborting a CF fetus, or now by preimplantation
genetic diagnosis (PGD) where a cell is analyzed from each embryo and
only unaffected embryos are transferred.
Adapted
from “Conceptions & Misconceptions: The Informed Consumer’s
Guide through the Maze of In Vitro Fertilization & Other Assisted
Reproduction Techniques” by Arthur L. Wisot, M. D., FACOG and David
R. Meldrum, M.D., FACOG, Hartley & Marks Publishers, Point Roberts,
WA (published Spring 2004) |
