Testicular
failure
The semen may contain no sperms (azoospermia),
few sperms (oligospermia) or predominantly abnormal sperms. The cause is presumably
some form of testicular dysfunction which may follow mumps infection, exposure
to radiation or testicular trauma but is more often unknown. The normal feedback
mechanism to control the production of gonadotrophic hormones is disturbed if
there is testicular atrophy and the serum levels of luteinising hormone and
follicle-stimulating hormone will be high. In some cases of azoospermia the
testicular biopsy shows a failure of sperm development. Many treatments have
been attempted but the results have been disappointing.
Obstruction
Azoospermia may also be due to obstruction to
the pathway of spermatozoa from the testis via the epididymis to the
ejaculatory ducts. The testicular biopsies will show active spermatogenisis. If
the site of the obstruction can be identified by vasography it
may be possible
to perform a bypass operation. Unfortunately, even in the best hands, the
results of epididymovasostomy are poor.
In some couples there appears to be an
immunological cause for the infertility with clumping of sperms exposed to serum
or cervical mucous.
Intracytoplasmic
sperm injection
Intracytoplasmic sperm injection has
revolutionised the management of male factor infertility. Spermatozoa harvested
from the ejaculate, by aspiration of the epididymis or even from testicular
biopsy, can be injected in vitro into ova obtained from the mother.
Embryos are then transferred into the mother’s uterus at the 4—6 cell stage.
Vasectomy
for sterilisation
Vasectomy for sterilisation is one of the most
commonly performed operations throughout the world. It should only be
undertaken after the couple has been carefully counselled. They
need to know
that the
operation is performed to make the man permanently sterile. They should be warned that they should continue with
their normal contraceptive precautions until the success of the operation has
been confirmed by semen analysis performed 12—16 weeks after surgery. They
should also be warned of the remote but important possibility of spontaneous
recanalisation which may restore fertility unexpectedly.
Vasectomy
is easily and painlessly performed under local anaesthetic. The vasa are
delivered through tiny bilateral or a single midline scrotal incision. For
medicolegal reasons it
is wise to remove
a segment of each vas
to prove that it
has been
successfully divided. Burying the cut ends or turning them back on themselves
probably helps to prevent them rejoining.