Unilateral absence of vas deferens: prevalence among 23,013 men seeking vasectomy

PURPOSE: To determine the prevalence of unilateral absence of vas deferens (UAVD) in men with both testes seeking vasectomy. MATERIALS AND METHODS: Computerized charts of 23,013 patients encountered between January 1994 and December 2013 in one university hospital and two community clinics of Quebec City, Canada, were searched. Pre-vasectomy consultation, operative reports and semen analysis results were reviewed to identify cases of UAVD. Cases were categorized as confirmed (unilateral vasectomy and success confirmed by semen analysis) or possible congenital UAVD further sub-categorized according to whether or not a scrotal anomaly was present. RESULTS: Among 159 men identified as potentially having UAVD, chart review revealed that 47 had only one testicle, 26 had bilateral vasa, and four were misdiagnosed (post-vasectomy semen analysis [PVSA] showing motile sperm after unilateral vasectomy) leaving 82 men deemed cases of UAVD (0.36%, 95% confidence interval 0.28% to 0.43%). These were classified as confirmed (n=48, 0.21%) and possible (n=34, 0.15%; 22 without and 12 with scrotal anomalies) congenital UAVD. The misdiagnosis ratio of UAVD was low when scrotal content was otherwise normal (1:48), but higher if anomalies were present (3:12). CONCLUSIONS: Most surgeons who perform vasectomy will encounter cases of UAVD. In most suspected cases, it is safe and effective to proceed with unilateral vasectomy under local anesthesia while stressing the need for PVSA. Further studies or scrotal exploration may be considered in patient with prior scrotal surgery.