Factors Affecting the Sperm Recovery Rate of Vasovasostomy

The microsurgical vasovasostomy is a treatment of choice in restoring sperm to the ejaculate and in establishing pregnancy for men wishing to resume paternity after vasectomy. The success of the reversal is dependent upon the length of time since the vasectomy, vasectomy techniques, the experience of the surgeon, and many other factors.

Success rate for vasectomy reversal is generally reported in two ways: sperm recovery rate (patency success rate) and pregnancy rate. This blog will talk about sperm recovery rate after vasovasectomy. The relationship of pregnancy rates and reversal procedures will be discussed in a separate blog.

The sperm recovery rate of vasovasostomy is influenced by several factors.

1. The single most important factor in whether a vasectomy reversal procedure will be successful is the interval in time (years) between the vasectomy and the vasectomy reversal. Our clinic data is consistent with reported studies demonstrating that sperm recovery rate after vasovasostomy is inversely related to the duration of vasal obstruction after vasectomy. Vasectomy has time dependent adverse effects on the testis, epididymis, and vas deferens (this will be discussed separately).

2. The surgical technique of vasectomy also affects the success rate of vasovasostomy. If the surgeon or family physician uses a technique that is difficult to reverse, such as cutting or burning away too long of segments of vas, or cutting too high or too low, then it will be much more difficult to do anastomosis without tension due to the shortage of vas and too much scar in the tissue. The shorter the proximal end, the greater the “back-pressure”, which will cause “blowout” and scarring of the epididymal tubule.

3. The presence of sperm granuloma in the proximal end was associated with better sperm quality at the anastomosis site and had an improved outcome.

4. The quality of vasal fluid was correlated to a successful outcome after vasovasostomy. If the vasal fluid is clear and lightly milky in color, it is more likely that sperm will be found in the ejaculate following vasovasostomy.

5. The presence of sperm in the fluid retrieved from the proximal vas deferens before anastomosis was highly correlated with successful patency.

6. Finally, the surgeon’s experience and microsurgical skills is important for successful vasectomy reversal procedures.

  • If the ends of vas are not precisely aligned, it may result in leakage of sperm fluid, inflammation, and scarring. While technical failures can occur even with a very experienced microsurgeon, they are far more likely in less experienced surgeons.
  • Many vasectomy physicians use cautery during vasectomy procedures. Careless and extensive cauterization damages the blood supply to a long length of the vas. Vasectomy reversal procedures could further cause inadequate blood supply to the vas. Scar tissue develops at the site of anastomosis, causing a blockage and late failure. This type of failure usually results in some sperm being present early after surgery, with failure 3-12 months later.
  • Therefore, it is important to ask how many reversal procedures the surgeon does every year, as there are will be a big difference between a surgeon who does less than ten reversal procedures and a surgeon who does 200 reversal procedures every year.

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