The Case for Early Post-Vasectomy Semen Analysis Combining Small Non-Motile Sperm and Azoospermia

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. χ2 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.