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.
