The case for early post-vasectomy semen analysis combining small non-motile sperm and azoospermia

Abstract

Background: Post-vasectomy semen analysis timing and criteria guidelines have evolved over time. Through analysis of our unit's practice of post-vasectomy semen analysis from earlier sampling protocols at 8 weeks to single sampling at 12 weeks then 16 weeks, the impact on success rates and patient compliance were assessed. In addition, the use of small numbers of non-motile sperm and azoospermia combined rates as a marker of sterility were examined. Methods: All patients who underwent vasectomy in 2011 (8 and 12-week samples), 2013 (12-week samples) and 2016 (16-week samples) were included. Patients were given written and verbal instructions explaining the sample delivery protocol and samples. χ 2 Testing was used to compare patient compliance and the results of post-vasectomy semen analysis with significance set at P<0.05. Results: In total 1124 vasectomies were performed, with 21% (N=232) of patients non-compliant with submitting samples at the requested time period. Azoospermia rates increased with a longer time to post-vasectomy semen analysis from 82% to 95%, P<0.001; however, declining compliance meant the proportion of patients given clearance remained the same (70% vs. 68%, P=0.32). Rates of small non-motile sperm declined over an increasing time to post-vasectomy semen analysis. Therefore combined azoospermia and small non-motile sperm rates remained stable over an increasing sampling time (95% vs. 99%, P=0.39). Conclusion: The use of earlier post-vasectomy semen analysis is recommended as patient compliance decreases with the time from vasectomy. When azoospermia and small non-motile sperm rates are combined the rates of success of the procedure remain the same over time therefore earlier testing at 8 weeks is feasible without compromising clearance rates. Level of evidence: Not applicable for this single centre audit.