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In
the late 1980's, Dr. Sherman Silber in St. Louis proved
that sperm obtained directly from the scrotum could
be used to successfully fertilize eggs and achieve viable
pregnancies. While this procedure was originally intended
for men who are born with an obstruction in the genital
tract (congenital absence of the vas deferens), it has
become clear over the past decade that men with previous
vasectomies can benefit from similar procedures as well.
The
development and maturation of sperm occurs in the testes.
The testes also produce most of the testosterone in
men. The sperm begins its trip through the male ducts
in an enlarged portion of the ducts called the epidydimis.
This duct eventually becomes the vas deferens (vas).
Along the route of the vas, the prostate and seminal
vesicles add the fluid portion of the ejaculated semen.
When a vasectomy has been performed, the vas deferens
is blocked before the area where the seminal vesicles
add the fluid. That is why these men still produce semen,
but no sperm. Dr. Silber microsurgically removed sperm
from the epidydimis and achieved viable pregnancies
through assisted reproductive procedures, thus proving
that sperm do not have to make the trip through the
ducts to achieve fertilizing potential.
Vasectomies
represent an important and effective method of "permanent"
birth control. For a variety of reasons, a small percentage
of men who have a vasectomy later desire more children.
Until recently, if semen was not frozen at the time
of the surgery, microsurgical reversal of the vasectomy
has been the only option for these men. Vasectomy reversal
has several disadvantages, however. Vasectomy reversal
represents major surgery of the scrotum. Most men with
long-standing vasectomies develop sperm antibodies that
may inhibit fertilization, even if the reversal procedure
is surgically successful. Finally, reversals done more
than 7 years from the original procedure are associated
with very poor pregnancy rates. Unfortunately, many
men seeking fertility after a vasectomy fall into this
last category.
Removing
sperm directly from the scrotum, combined with In-vitro
fertilization (IVF), represents an excellent alternative
to vasectomy reversal. The original microsurgical approach
is known as "Microsurgical epididymal sperm aspiration,"
or "MESA." This procedure produces enough
sperm to freeze for future use. However, like vasectomy
reversal itself, the procedure involves major surgery
of the scrotum, is relatively expensive, and can often
only be performed once on each side because scar tissue
hinders the ability to find the duct on subsequent attempts.
Over
the past few years, HRC doctors have developed two non-surgical
alternatives to MESA. The first approach is called,
"Percutaneous epididymal sperm aspiration"or,"PESA."
The second alternative is called, "Testicular sperm
extraction," or, "TESE." Both procedures
can be done using local anesthesia. With PESA, a small
needle is guided through the skin into the epididymis,
and a small amount of fluid containing sperm is aspirated.
In contrast, with TESE, a small amount of tissue is
directly removed from the testis using a small biopsy
needle. In either case, relatively small numbers of
sperm are obtained, and these can fertilize the female
partner's eggs through Intracytoplasmic sperm injection
(ICSI), where individual sperm are actually injected
into the eggs. None of these procedures produce enough
mobile sperm for simple artificial inseminations.
Potential
complications of the non-surgical procedures include
infection and bleeding. Bleeding under the scrotal skin
can theoretically cause the formation of a painful blood
clot known as a hematoma. In over 5 years of performing
these procedures, we have not seen either of these complications.
Before
proceeding with any of these treatments, the male partner
should be evaluated by the person who will perform his
procedure. An appropriate history and physical examination
should be performed, focusing on potential factors that
could impact on likely successful aspiration of sperm.
The physical exam can identify potential problems that
might be encountered and can help the physician estimate
the likelihood of finding adequate amounts of viable
sperm. We measure serum levels of testosterone and FSH
in the men to make sure they are producing enough hormones
to sustain normal sperm development.
As
with routine IVF cycles, the female partner uses injectable
hormones to both stimulate multiple egg production and
to control the timing of ovulation. The egg retrieval
is done vaginally, using an ultrasound probe to guide
a needle into the ovaries. This procedure can be done
with local anesthesia, or with conscious sedation. The
PESA or TESE is done on the same day, and the eggs are
inseminated shortly after the conclusion of both procedures.
Three days later, a small number of embryos are inserted
through the cervix into the uterus. The number of embryos
transferred depends on the age of the woman and the
quality of the embryos. Extra embryos can be frozen
for future use. Over the past year, the doctors at HRC
have been addressing the issue of multiple births by
transferring lower numbers of embryos in younger patients.
We can do this, in part, because of the quality of our
freezing program, giving couples a realistic second
chance.
The choice of procedure is largely dependent on physician
preference. All three variations of the male procedure
are available at HRC. Over the past several years, we
have experienced a 20-30% ongoing pregnancy rate with
non-surgical sperm extraction procedures. The success
rates varies, based on various factors, maternal age
being one of the most important. We believe, that for
couples in whom the male partner has a vasectomy more
than 7 years old, these success rates following single
procedures are greater than the overall success rates
with vasectomy reversal. For younger women, the overall
success rate following the initial combination of PESA/TESE
and IVF, is enhanced if there are frozen embryos available
for another embryo transfer.
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