Micromanipulation, the handling of egg and sperm by microscopic instruments,
is used to improve the chances of fertilization in cases with impaired
sperm function. ACRM offers the most advanced micromanipulation technique,
called Intracytoplasmic Sperm Injection (ICSI), in which a single sperm
is injected directly into the egg using a glass micro-needle. ICSI has
revolutionized the treatment of male infertility by overcoming barriers
to sperm entry into the egg. Fertilization is possible even in cases with
low sperm or compromised sperm function.
Male Factor Infertility
As many as one third of the infertility cases in the United States may
be attributed to the male partner. There are several possible causes:
A low sperm concentration or "low sperm count"
Low sperm motility (few sperm which swim)
Sperm which are not able to fertilize eggs because they are not functional
due to some abnormality in their structure or biochemical make-up
Combinations of some of these factors.
In vitro fertilization (IVF) has proven to be very effective for treating male infertility. This is
because the motile (swimming) sperm can be collected and concentrated
from the husband's semen and placed in direct contact with the egg in
a culture environment in the IVF laboratory. Through the increased number
of swimming, and presumably functional, sperm around the egg, the chances
of fertilization are improved over intercourse or intrauterine insemination.
Male Infertility Treatment
There are cases of male factor infertility which cannot be addressed even
through IVF. In these cases, there are so few sperm, or sperm which are
completely immotile (not swimming at all), that even if they are placed
in culture with the egg, fertilization will not take place.
An ideal approach to these severe forms of male infertility is to directly
inject a single sperm cell into the egg. In this way, the sperm cell is
relieved of the work of penetrating the several layers which surround,
nourish, and protect the egg. Also, relatively few sperm are needed since
only one sperm cell is required for each egg.
About ICSI
Intra-Cytoplasmic Sperm Injection is a technique that allows fertilization
in cases that would have been virtually hopeless.
Be aware, however, that even though the sperm is placed inside the egg
by the injection procedure, the fertilization process may not be completed.
Fertilization is a complex continuum of sperm and egg interaction, not
simply the entry of the sperm into the egg. If this interaction does not
occur following delivery of the sperm into the egg, fertilization failure
may still result.
Needle inserted
Sperm injected
Sperm left inside
The ICSI Procedure
ICSI is performed using instruments called micromanipulators. These allow
the biologist to "handle" the cells under microscopic observation
with magnification of 200 to 400 times. The egg is gently held steady
using an instrument called a holding pipette. Using a glass micro-needle,
a single sperm is aspirated into the tip of the needle and then carefully
injected into the egg. The egg can be examined 15 to 18 hours later to
determine if fertilization has occurred.
ICSI Success
The pregnancy rates achieved through IVF with ICSI is comparable to those
observed with IVF without ICSI. In both IVF with and without ICSI, the
incidence of pregnancy is dependent upon a number of factors: the woman's
age, any infertility factors she may have, the number of embryos transferred
to her uterus, and uterine receptivity.
