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Over the last several years, the field
of Assisted Reproductive Technology (ART) has advanced
rapidly in providing assistance to couples with male
factor infertility. In couples that are having difficulty
trying to conceive a child, approximately 40% will be
diagnosed with a male problem. A routine semen analysis
is used to determine the adequate number and quality
of sperm to predict the fertilization potential.
When
sperm are produced by ejaculation but in very low numbers,
In-vitro Fertilization (IVF) along with an assisted
fertilization technique called "ICSI" (Intracytoplasmic
Sperm Injection) has helped many couples achieve a pregnancy.
A cycle of IVF involves daily injections for approximately
8-10 days to stimulate a woman to produce many mature
eggs that are retrieved in a minor outpatient procedure.
ICSI is then performed by directly injecting a single
sperm into a one egg using microscopic instruments.
The next day, the injected eggs are checked for fertilization
and, within several days, a select number of embryos
are transferred to the woman's uterus in hopes of achieving
a pregnancy.
Until the mid 1990's, donor sperm was
the only treatment for absence of sperm in the ejaculate
(azoospermia). Some men have a condition where their
reproductive ducts may be absent or blocked (obstructive
azoospermia or OA), whereas others may have no sperm
production with normal anatomy (non-obstructive azoospermia
or NOA). A minor outpatient procedure called "TESA"
(TEsticular Sperm Aspiration) may be offered to obtain
sperm directly from the testes where it is produced.
If successful, the sperm can then be used with IVF/ICSI.
Using a serum FSH and palpating the male reproductive
ducts and size of the testis, urologists can usually
distinguish between OA and NOA. Specifically, an elevated
FSH and small testicular size is consistent with NOA.
Azoospermia is found in 10% of male infertility cases.
Patients with OA, due to congenital bilateral absence
of the vas deferens (CBAVD) or those in whom reconstructive
surgery fails, have historically been considered infertile.
Men who cannot produce sperm in their testes with apparent
absence of spermatogenesis diagnosed by testicle biopsy
are classified as NOA. This article will discuss advances
in the surgical treatment of azoospermia and does not
include hormonal disorders such as hypogonadotropic
hypogonadism.
Surgical retrieval of spermatozoa
from testes combined with ART has given new hope to
those patients previously considered infertile. In cases
of surgically irreparable AO or in cases of CBAVD, Microsurgical
Epididymal Sperm Aspiration (MESA) with standard IVF
has been shown to yield fertilization and pregnancy.
However, the results were poor and unpredictable. TESA
is now a well-accepted technique in the treatment of
men diagnosed with OA or NOA but requires ICSI due to
the immature fertilization potential of testicular sperm.
Since testicular biopsy is an invasive procedure, the
efficient use of TESA would reduce surgical aspirations
to a single sperm retrieval by including cryopreservation
(see below).
Recently, Dr. Bin Wu's group has defined
an optimal technique for fresh and frozen-thawed testicular
sperm for ICSI in azoospermic patients. This technique
involves in vitro maturation of fresh and frozen testicular
sperm. Although TESA is used frequently to obtain sufficient
sperm for ICSI, few free spermatozoa demonstrate twitching
motility and most are completely immotile in the initial
testicular biopsied samples. This research demonstrates
that less than 3% sperm motility is observed following
the initial collection of testicular biopsy samples.
In most cases of NOA, it is very difficult to find sufficient
motile sperm in the initial fresh or frozen-thawed sample
for ICSI.
When Dr. Wu's group performed testicular biopsied
tissue in-vitro culture for 24 hrs, the number of motile
sperm showed a remarkable increase and reached a maximum
motility rate between 48 and 72 hours. Based on these
observations, after 24 hours of in vitro culture, there
are enough motile sperm including "twitching"
sperm for ICSI. Therefore, it appears that the optimal
time for ICSI using testicular sperm is after 24-48
hours of culture. This may allow TESA to be performed
one or two days before oocyte retrieval and provides
flexibility in scheduling these procedures in clinical
practice.
Cryopreservation of TESA specimens can
avoid repeated testicular biopsies in azoospermic patients
in whom the only source of spermatozoa is the biopsy.
Testicular sperm cryopreservation using a simple freezing
protocol is promising in patients with AO and NOA augmenting
the overall success achieved after surgical sperm retrieval.
This study indicates that the frozen-thawed testicular
sperm displayed a similar motility to fresh samples
during culture. As a result, the cryopreservation of
testicular biopsy specimens routinely is recommended
in clinical practice. Nevertheless, there remains controversy
in the medical literature regarding the optimal processing
of sperm with NOA, namely using freshly retrieved vs.
frozen sperm.
In summary, TESA with ICSI has successfully
treated azoospermia and offers approximately a 40% live
birth rate from OA and NOA patients. The freezing and
in vitro maturation of testicular biopsy specimens are
useful approaches to the management of testicular biopsy
samples from both AO and NOA patients. These techniques
offer the possibility of several attempts at IVF/ICSI
from a single testicular biopsy sample. One to three
days of in-vitro culture for fresh or frozen samples
before an oocyte retrieval may increase the availability
of motile spermatozoa for ICSI. Testicular biopsy freezing
and subsequent culture may be a reliable alternative
for patients undergoing TESA on the same day of oocyte
retrieval, allowing for flexibility in scheduling patients
for clinical procedures.
David Heinkel is the IVF Embryology Laboratory
Director of Fertility C.A.R.E. (Center of Assisted Reproduction
and Endocrinology). Dr. Mark P. Trolice is the Director
of Fertility C.A.R.E and is Board-certified in Reproductive
Endocrinology and Infertility (REI). He is also the
Division Director of REI at Arnold Palmer Hospital for
Children and Women in Orlando. Please direct any inquiries
by calling 407-672-1106 or email info@myfertilitycare.com
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