Sperm retrieval
techniques have given hope to men with obstructive and nonobstructive
azoospermia. The etiology of obstructive azoospermia includes men with
a previous vasectomy, ejaculatory duct obstruction, and congenital
bilateral absence of the vas deferens. Sperm production is normal in
these men, though sperm parameters may decrease with chronic
obstruction. Sperm are extracted using both percutaneous sperm
retrieval and open microsurgical techniques. In percutaneous
epididymal sperm aspiration (PESA), sperm are aspirated through a
butterfly needle that is placed into the caudal portion of the
epididymis.
Adequate numbers of
sperm are often retrieved allowing for cryopreservation and future
ICSI cycles. With the advent of microsurgical epididymal sperm
aspiration (MESA), sperm are retrieved in higher numbers than with
PESA, allowing for cryopreservation of large numbers of sperm. In our
practice, PESA is attempted first since it is a less invasive
procedure that often produces enough sperm for ICSI. If sperm
collection fails, MESA is the second option. Men with nonobstructive
azoospermia have an impairment of normal spermatogenesis. Their
pregnancy and fertilization rates with ICSI are lower than for men
with obstructive azoospermia. These men normally do not have sperm
present in their epididymis for retrieval. Thus, testicular sperm
retrieval is performed with either testicular fine- needle aspiration
of the testes (TESA) or open testicular biopsy.
Recovered sperm can
either be used for ICSI or cryopreserved and thawed on the day of
retrieval. Nonobstructive azoospermic patients need to be counseled
that sperm retrieval techniques may fail to recover sperm. In the
event that sperm is not retrieved, couples may opt for donor sperm.
ICSI uses a single washed sperm placed into a
viscous solution of 10% polyvinyl pyrrolidine, which impedes sperm
movement. The spermatozoa flagellum is crushed, which causes
immobilization and increases permeability of the sperm membrane,
enhancing nuclear decondensation and pregnancy rates. A
morphologically normal sperm is aspirated tail-first into an injecting
pipette. The sperm is injected through the zona pellucida and into the
ooplasm with the polar body at 12 o'clock (see Fig. 39.3). Injected
sperm are placed into culture microdroplets under oil. Eighteen hours
later, oocytes are examined for fertilization comparable to standard
insemination in vitro. Normal fertilized eggs are moved to individual
culture microdroplets under oil and transferred 72 hours from
insemination.
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