A vasectomy is the procedure in which the vas deferens (sperm tubes) of a man are cut and tied or clipped in order to prevent him from fathering children. It is a simpler operation than the sterilisation (tubal ligation) of a woman and is growing in popularity as men increasingly accept responsibility for family planning. Most men are very anxious about a vasectomy, but there is no effect on their libido or masculinity.
Sperm are produced by the testes throughout adult life at a relatively constant rate. The sperm enter a complex network of small tubules in the epididymis, which unite to form the vas deferens. The sperm pass along this tube to a storage sac (the seminal vesicle) in the groin where they await the next ejaculation.
The walls of the sperm storage sac secrete a fluid, which nourishes the sperm, and along with an exudate from the prostate gland, forms 95% of the semen passed by the man during intercourse. When he ejaculates, the sperm and supporting fluid (called semen when combined) pass down the sperm tube to its junction with the urethra, and then along this tube to the outside of the penis.
In a vasectomy operation, a local anaesthetic numbs the side of the scrotum, and through a small incision, the doctor cuts, burns and ties or clips the sperm tube (vas deferens) which lies just under the surface, so no further sperm can pass along it from the testes. Usually a small section of the vas is removed to prevent the ends from rejoining. The procedure may be done in the doctor’s rooms, or as a day patient in a private hospital. The procedure is very simple and brief, and no pain is felt. There is usually some bruising and discomfort in the scrotum for a few days after the operation, but other complications are uncommon. In about 5% of men there is long-term discomfort in the scrotum, and in a very small group of men this discomfort may be quite significant. There is always a small risk that the cut sperm tubes may spontaneously reconnect at a later time making the man fertile again.
The man is not immediately sterile after the operation. Because sperm are stored in the sac above where the tube is tied, this must be emptied by about a dozen ejaculations over the next few weeks. It is essential to have a test done about six weeks after the operation to check that no sperm are getting through or remaining in storage.
The couple can stop their other contraceptive measures only after this test is confirmed.
The male hormones that establish and maintain masculinity are also produced in the testes. These are not affected in any way by the operation as they enter the blood stream directly from the testes and continue to function normally. The man’s ejaculation is not affected either, as the fluid from the sperm storage sac is passed as normal.
Although reversal procedures (vasovasostomy) are sometimes possible, it should be considered to be a permanent procedure at the time it is performed. The success rate of vasectomy reversal is higher than with a tubal ligation but by no means high enough for a couple to be able to regard it as anything but a possibility. A decision about a vasectomy needs to be taken on the basis that it is permanent and that should their marriage break down or a child die the man will be unable to have further children.