About 35,000 men per year undergo vasectomy reversal in the United States. The most common reason is remarriage and the desire for more children. Occasionally, an unfortunate individual will have lost a child and desire another. Infection, deformities, trauma, and previous surgery are less frequent indications for vasovasostomy or epididymovasostomy. A problem with duct obstruction is suspected in men with normal hormones and normal testis size and no sperm in the ejaculate.

There are several methods for performing a vasovasostomy. None has been proved superior to any other, except that magnification with an operating microscope has been shown to result in better success rates. Generally, either a single-layer anastomosis or a strict, two-layer anastomosis is performed (

Figure 42-14). Although these procedures are technically different, the experience of the surgeon is the most important factor for success. Depending on these factors, 95% or more of patients may have a return of sperm after a vasovasostomy. If the vas fluid contains no sperm below the vasectomy site, a second problem may exist in the delicate tubules of the epididymis. The longer the time since vasectomy, the greater the “back-pressure” behind the blocked vas deferens. This may cause a blowout at some point in the single, 18-foot-long epididymal tubule, the weakest point in the system. A blowout results in blockage of the tubule as it heals. In this case, the vas must be connected to the epididymis above the blowout to allow sperm to travel through the reproductive tract. This is called an epididymovasostomy. After epididymovasostomy, approximately 60-65% of men will have sperm in the ejaculate. These rates, however, have improved remarkably during the last several years, with the evolution of surgical techniques and equipment.

The achievement of sperm in the ejaculate after vasovasostomy depends on the surgeon and the patient, but pregnancy after surgery obviously involves a third party. It is rare that more than 67% of men who have normal sperm counts after vasectomy reversal will impregnate a woman. Therefore, it is critical to delve into the reproductive health of the female partner before embarking on the procedure. Other reasons that reproductive tract microsurgery fails are (1) the quality of preblockage semen may not have been normal; (2) ASAs develop in roughly 30% of men who have had vasectomies (high antibody levels may impair fertility); (3) postsurgical scar tissue can develop at the anastomotic site, causing another blockage; (4) when the vas deferens has been blocked for a long time, the epididymis is adversely affected and sperm maturation may be compromised.