Vasectomy reversal is comparable in safety to vasectomy. The risks of vasectomy are outlined below from most common to least common. The main risk of vasectomy reversal is that pregnancy may not occur. The least common risks are severe infection or chronic pain as a result of the procedure.
Failure to achieve pregnancy
The main risk of vasectomy reversal is future pregnancy may never happen naturally.
The vasectomy reversal may be perfectly performed, without any complications, and sperm may not reappear in the ejaculate or return in numbers inadequate to cause pregnancy.
Preexisting male infertility
Many men will have a vasectomy before having children or a small number of children. Some of these men may have had unrecognized male infertility or sub-optimal male fertility before their vasectomy. When these men have vasectomy reversal the factors contributing to male infertility will continue to be present.
Vasectomy induced epididymal dysfunction
The most common reason this can occur is because the epididymis in some men may become dysfunctional after a vasectomy. The epididymis is thought to become dysfunctional because of increased pressure caused by the continual production of sperm after the vasectomy that have nowhere to exit. This causes increased pressure, which can cause gradual dysfunction of the epididymis. The epididymis may cease producing sperm or produce dysfunctional sperm.
Formation of anti-sperm antibodies
Some men will form immune reactions against their own sperm after vasectomy and will form anti-sperm antibodies. The contribution of anti-sperm antibodies to male infertility and sperm dysfunction is controversial because many men may develop anti-sperm antibodies; however, most will not have infertility or sperm dysfunction.
Combinations of these issues can also contribute in an additive fashion to the insufficient reappearance of sperm in the ejaculate.
Equally possible is the vasectomy reversal may be 100% successful but the female partner may be the source of infertility. The most common conditions found in women as a cause for infertility are not ovulating (releasing eggs) regularly, blockage of the fallopian tubes, and difficulty conceiving because of increasing maternal age.
Some couples will have everything working perfectly (normal sperm count, regular ovation, and normal fallopian tubes) and not be able to become pregnant because of unexplained infertility.
Occlusion of the vas deferens
The vas deferens may heal with scar tissue and be blocked at the repair sites after vasectomy reversal.
The inside of the vas deferens is delicate and small. If the repair site heals aggressively with scar tissue then the inside of the vas deferens may be blocked and sperm may not be able to be transported to the seminal vesicles.
One or both of the vas deferens could heal closed with scar tissue. If blockage occurs in only one vas deferens and the other heals without blockage then sperm will often reappear in the ejaculate in adequate enough amounts to cause pregnancy. Very often men who have one open and fully functioning vas deferens will have normal sperm counts.
The chance of one or both of the vas deferens healing with blockage is 3-10%.
A hematoma is a collection of blood that forms a localized blood clot and can occur after any surgical intervention.
Arterial hematomas occur rapidly and often in less than twelve (12) hours after a vasectomy reversal. Venous hematomas occur less quickly and usually within 24 to 36 hours. Small hematomas may cause pain and discomfort but can be reabsorbed by the body without surgical intervention. Large hematomas will cause pain and discomfort and will require surgical evacuation.
The risk of hematoma formation after vasectomy reversal is less than 5%.
Infection is possible after any surgical procedure. If an infection were to occur after vasectomy reversal it can often be treated with oral antibiotics but may require hospitalization. If an infection persisted an abscess could (form) and hospitalization and drainage may be required.
The overall risk of infection after vasectomy reversal is less that 3%.
Bleeding is a possible complication of almost any surgical intervention.
Vasectomy reversal requires more surgical manipulation of the vas deferens and the risk of bleeding after vasectomy reversal is likely higher than with vasectomy. Bleeding risk are increased if the patient is on a blood thinner, has a bleeding disorder, or has scar tissue from previous scrotal surgery or infection.
Overall the risk of serious bleeding during or after a vasectomy reversal is less than 1%.
Most cases of chronic pain after vasectomy reversal are mild and cause minimal disruption to a patient’s daily life. Granulomas (small collections of sperm) or neuromas (abnormally healing nerves) are thought to be the cause of most of these cases of mild but chronic pain after vasectomy reversal.
Chronic, severe testicular pain is a rare but possible risk of vasectomy reversal.
This complication can occur after any surgical manipulation of the testicles or vas deferens (vasectomy or vasectomy reversal) but can also occur after surgery to other areas of the male genitourinary tract. The cause for severe, chronic pain is unclear but is felt to be caused by changes in the nerves during the healing process after surgery. This complication is poorly understood.
The estimate of chronic pain after vasectomy reversal is difficult to determine but should be less than 1%.
Testicular atrophy is a rare risk of vasectomy reversal.
This complication is caused by repeated insult to the blood supply of the testicle. This can occur in patients who have had multiple scrotal surgeries and the risk may be increased in patients who have underlying disorders of the circulatory system.
The risk of testicular atrophy after vasectomy reversal is less than 0.5%.