See S. D. Mumford, Vasectomy: The Decision-Making Process (1978); G. Denniston, Understanding Vasectomy (1978).
Severing of the vas deferens, which carries sperm from the testes to the prostate gland, to cause sterility or prevent infection. This relatively simple procedure, which can be performed in a doctor's office with local anesthetics, removes the ability to father children without affecting ability to achieve erection or orgasm. The vas is cut near its beginning, in the scrotum. The cut ends may be sealed off or left open. Reversal is more likely to succeed in the latter case; microsurgery has improved the success rate.
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There are some variations on the procedure such as no-scalpel (keyhole) vasectomies, in which a sharp hemostat, rather than a scalpel, is used to puncture the scrotum. Another type of vasectomy which may reduce the risk of chronic pain is called an "open ended" vasectomy. A "normal" vasectomy typically seals both ends of the vas deferens with stitches, heat, metal clamps or a combination, after cutting. The open-ended vasectomy obstructs only the top end of the vas deferens. With this method sperm leaks out from the lower severed end of the vas deferens and into the scrotum, thus hopefully avoiding a build-up of pressure in the epididymis. The likelihood of long-term testicular pain from "backup pressure" seems to be reduced using this method.
When the vasectomy is complete, sperm can no longer exit the body through the penis. The testicles continue to produce sperm, but they are broken down and absorbed by the body. Much fluid content is absorbed by membranes in the epididymis, and much solid content is broken down by the responding macrophages and re-absorbed via the blood stream. Sperm is matured in the epididymis for about a month once it leaves the testicles. Approximately 50% of the sperm produced never make it to the orgasmic stage in a non-vasectomized man. After vasectomy, the membranes increase in size to absorb and store more fluid; this triggering of the immune system causes more macrophages to be recruited to break down and re-absorb more of the solid content. Within one year after a vasectomy, sixty to seventy percent of vasectomized men develop antisperm antibodies. In some cases, vasitis nodosa, a benign proliferation of the ductular epithelium, can also result. The buildup of sperm increases pressure in the vas deferens and epididymis. To prevent damage to the testes, these structures eventually rupture in more than half the cases. The entry of the sperm into the scrotum causes sperm granulomas to be formed by the body to contain and absorb the sperm which the body treats as a foreign substance.
Early failure rates, i.e. pregnancy within a few months after vasectomy, are below 1%, but the effectiveness of the operation and rates of complications vary with the level of experience of the surgeon performing the operation and the surgical technique used.
Although late failure, i.e. pregnancy after recanalization of the vasa deferentia, is very rare, it has been documented.
Worldwide, approximately 6% of married women using contraception rely on vasectomy.
Couples who choose vasectomy are motivated by, among other factors:
Animal and human data indicate that vasectomy does not increase atherosclerosis and that increases in circulating immune complexes after vasectomy are transient. Furthermore, the weight of the evidence regarding prostate and testicular cancer suggests that men with vasectomy are not at increased risk of these cancers.
Post-Vasectomy Pain Syndrome (PVPS), genital pain of varying intensity that may last for a lifetime, is estimated to appear in between 5% and 35% of vasectomized men, depending on the severity of pain that qualifies for the particular study The pain can be orchialgia, pain with intercourse, ejaculation, or physical exertion, or tender epididymides. In one study, vasectomy reversal was found to be 69% effective for reducing the symptoms of chronic post-vasectomy pain. Treatment options for 31% of patients whose pain did not respond to vasectomy reversal were limited. The study was very small, only evaluating 13 patients, making it difficult to draw solid conclusions. In severe cases castration has been resorted to.
Although men considering vasectomies should not think of them as reversible, and most men and their spouses are satisfied with the operation, there is a procedure to reverse vasectomies using vasovasostomy (a form of microsurgery first performed by Earl Owen in 1971). Vasovasostomy is effective at achieving pregnancy in only 50%-70% of cases, and it is very costly, with total out-of-pocket costs in the United States of approximately $7,000 . The rate of pregnancy depends on such factors as the method used for the vasectomy and the length of time that has passed since the vasectomy was performed. The reversal procedures are frequently impermanent, with occlusion of the vas recurring two or more years after the operation.
Since the body often produces antibodies against sperm, sperm counts are rarely at pre-vasectomy levels. There is evidence that men who have had a vasectomy may produce more abnormal sperm, which would explain why even a mechanically successful reversal does not always restore fertility. The higher rates of aneuploidy and diploidy in the sperms of men who have undergone vasectomy reversal may lead to a higher rate of birth defects .
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