Background: The examination of the vasal fluid at the time of vasectomy reversal has implications for surgical decision making with effects on patency and pregnancy rates. The Silber grading system characterizes these findings and has been used to help surgeons with the decision to perform vasovasostomy (VV) or the more technically challenging vasoepididymostomy (VE).

Objective: To determine both intraoperative and patient factors that affect pregnancy rates after vasectomy reversal.

Design: Retrospective review of prospectively maintained database.

Methods: This paper reviewed the results of a single surgeon series that encompassed >30 years of vasectomy reversals. Vasal fluid was characterized as opalescent, creamy, pasty or clear and intraoperative light microscopy was used determined if sperm parts were present or motile. Univariate and multivariate analysis examined the data set for significant factors that affected pregnancy rates.

Results: 2947 vasectomy reversals were included in the analysis. Pregnancy status was only known for 31% of these cases. Bilateral VV was performed 83% of the time and most patients fell into a Silber 1 to 3 classification. No factors met statistical significance for increasing the pregnancy rate, although the presence of motile sperm was almost significant (P =0.075).

Negative predictive factors for pregnancy were identified on multivariate analysis with increasing female age and the findings of either no sperm (odds ratio [OR], 0.08) or sperm heads only (OR, 0.46) on microscopy decreasing pregnancy rates. Rarely were sperm parts identified when pasty fluid was encountered.

Conclusions: The findings from this paper echo the findings of the Vasovasostomy study group, with the Silber grading system essentially dictating pregnancy rates.

Reviewer’s Comments: The decision to perform VV or VE can be a difficult one and is based on many factors including findings from the vasal fluid, time since vasectomy, and surgeon skill level. Few papers have examined this decision-making algorithm since the landmark paper by the Vasovasostomy study group in 1991. While most microsurgeons prefer VV to VE due to increased patency and pregnancy rates, the need to perform a VE is generally encouraged when pasty fluid or no sperm parts are found in the vas at the time of reversal. These findings are interesting and are another important addition to the literature. Unfortunately, despite the authors’ efforts, relatively few predictive factors were found. Their findings do somewhat parallel those published by the Vasovasostomy study group, wherein the Silber grading system appears to correlate with pregnancy rates. The authors identified sperm heads only (Silber 4) or no sperm (Silber 5) as negative predictors with motile sperm (Silber 1) almost achieving statistical significance as a positive factor.(Reviewer–Charles Welliver, MD).