Testicular Sperm Extraction (TESE)
In approximately 7% of men undergoing microsurgical epididymal sperm aspiration
(MESA), spermatozoa retrieval is not possible. In these patients in whom the
epididymal sperm reservoir is inaccessible, recent work has shown that whole,
motile sperm can be obtained from the testicle itself. Critical for the success
of testicular sperm extraction (TESE) is determination that the testis is making
mature sperm. This can be confirmed by diagnostic testicular biopsy, which is
sent for touch preparation (cytology), image analysis, and standard histology. If
mature sperm with complete tails are present on these examinations, TESE is
feasible. Because of the low number of sperm obtained with TESE, these sperm need
to be combined with the wifes eggs using intracytoplasmic sperm injection (ICSI).
The absence of mature sperm on these histologic examinations indicates that
successful retrieval is probably unlikely.
Patients who require TESE can be divided into two categories:
(1) The first set of patients are those men whose epididymis is not accessible
because of previous epididymal procedures or congenital efferent ductal obstruction
in the testis. This group with an obstructed testicle represents the first set of
patients in whom successful TESE was combined with ICSI, and in 1994 a 42% clinical
pregnancy rate was reported. More recent reports have demonstrated that in these
obstructed patients, testicular retrieval seldom yields unusable sperm.
(2) Patients with testicular biopsies demonstrating Sertoli-cell-only, maturation
arrest, or severe hypospermatogenesis represent another group of patients in whom
testicular sperm retrieval has been used. These patients, who until recently were
felt to be untreatable, can now often be treated effectively with in vitro
fertilization (IVF) and ICSI if areas of normal sperm production can be demonstrated
in a testicular biopsy.
In order to obtain testicular tissue from which to perform TESE, a standard
testicular biopsy is performed. In patients with nonobstructive azoospermia, several
biopsy specimens may need to be obtained from each testis in order to find areas of
active spermatogenesis. This can usually be performed through one small incision
on each side of the scrotum. This testicular tissue is then sent to the IVF
laboratory, where it is microdissected and processed in order to obtain sperm.
In patients with obstructive azoospermia, TESE is close to 100% successful at
retrieving sperm if diagnostic biopsies have previously demonstrated sperm in the
testis. In the nonobstructed testicle, recent studies have shown that 86% and 91%
of patients will have some sperm obtained by TESE. Pregnancy rates ranging between
28% and 50% per cycle of ICSI have been reported recently for patients with
nonobstructive azoospermia.
In conclusion, with the advent of ICSI, rapid advances have occurred in the
treatment of male factor fertility disorders. The testicle has now become an
accessible reservoir for the acquisition of sperm that can be used to fertilize the
wifes eggs and attain clinical pregnancies.
