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Scientific
Article Abstract for Dr. Silber's presentation
on TESE to ASRM
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"MICROSURGICAL
(TESE) TESTICULAR SPERM EXTRACTION FOR AZOOSPERMIC MEN: Abstract of Presentation
for Meeting of the American Society for Reproductive Medicine in September
1999"
Sherman J. Silber, M.D.
Introduction
Men with non-obstructive azoospermia caused by germinal failure can now
be treated successfully in many cases using testicular
sperm extraction (TESE--a
term which we coined in 1993) and ICSI.
There is a threshold of quantitative sperm production in the deficient testis,
below which no sperm will reach the ejaculate (azoospermia). This threshold
phenomenon of spermatogenesis is the reason that many cases of
non-obstructive azoospermia, sperm can often be extracted from testicular
tissue of azoospermic men with germinal failure, and used successfully for
ICSI. A prior diagnostic testicle biopsy analyzed quantitatively can often
predict the likelihood of finding such sperm during a TESE-ICSI attempt.
Objectives
We wished to examine the quantitative presence of spermatogenesis in different
regions of the testis in azoospermic men, in order to develop a rational
microsurgical strategy for the TESE procedure. The goal was to maximize
the chances for retrieving sperm from such men, to minimize tissue loss
and pain, and to preserve the chance for successful future procedures.
Materials and Methods
A prospective study involving quantitative histologic analysis of testicular
tissue in azoospermic men undergoing sperm retrieval for ICSI, with microsurgical
removal of large contiguous areas of testicular tissue, was initiated. Careful
analysis of tubular fullness observed at microsurgery was compared to quantitative
histology. There were three groups. One group with non-obstructive azoospermia
caused by testicular failure underwent diagnostic testicle biopsy prior
to a subsequent TESE-ICSI procedure. The diagnostic testicle biopsy was
analyzed quantitatively and correlated with the results of subsequent attempts
at ICSI. A second group of men with non-obstructive azoospermia underwent
multiple testis biopsy samplings from different regions of the testis in
a testicular mapping effort during TESE. A third group of men with non-obstructive
azoospermia underwent removal of large contiguous strips of testicular tissue
with microsurgical dissection and evaluation of tubular dilation.
Results
Men with non-obstructive azoospermia caused by germinal failure had a mean
of 0 to 3 mature spermatids per seminiferous tubule seen on a diagnostic
testicle biopsy. This compared to 17 to 35 mature spermatids per tubule
in men with normal spermatogenesis and obstructive azoospermia. This suggested
that a certain threshold of quantitative spermatogenesis was required in
order for some sperm to "spill over" into the ejaculate. In greater
than half of cases, there is some sperm in the testis despite none in the
ejaculate. Testicular "mapping" by multiple biopsy revealed a
basically diffuse quantitative distribution of spermatogenesis. However,
in 18 percent of cases undergoing multiple biopsy, there was just a rare
tubule with sperm in only one (1) or two (2) out of many biopsies. This
was explained in the cases that underwent microsurgical removal of contiguous
strips of testicular tissue. The distribution of spermatogenesis, however
sparse, was still always diffuse. A microsurgical approach resulted in the
least amount of tissue loss and minimal to no pain. Under the operating
microscope, tubules with no spermatogenesis were collapsed appearing, and
tubules with spermatogenesis were full. This difference was apparent with
Sertoli cell only, but not maturation arrest.
Conclusions
Incomplete testicular failure appears to involve a sparse, but diffuse,
distribution of spermatogenesis throughout the entire testicle, rather than
a patchy, or local distribution in just a few areas. This can often be observed
under the operating microscope. Therefore, in most cases only one modest
size biopsy is necessary. However, in cases where the distribution of sperm
is sparsely diffused, a microsurgical approach is required in order to either
locate tubules with spermatogenesis and remove minimal tissue, or to minimize
pain and tissue loss when greater amounts of tissue must be removed in order
to find sperm. Because of the diffuse distribution, a microsurgical TESE
procedure, by minimizing tissue removal or secondary damage, can assure
that future attempts at TESE-ICSI will not be compromised.
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