Vasovasostomy: kinetics and predictors of patency

To assess the timing of patency and late failure (secondary azoospermia) after vasovasostomy (VV) using standardized kinetics definitions.

Retrospective cohort study.

University-affiliated hospital.

Patients with obstructive azoospermia.

Vasovasostomy.

Univariate and multivariate logistic regression assessed predictors of patency and late failure. Patency was defined as any sperm return to the ejaculate; and >2 million total motile sperm (TMS) in ejaculate. Late failure after VV was defined as azoospermia; or <2 million TMS in ejaculate.

429 men underwent VV, with median follow up of 242 days. Mean time to patency was 3.25 months versus 5.29 months in the "any sperm" versus ">2 million TMS" groups. Finding sperm intraoperatively during VV significantly improved patency rates in multivariable analysis (odds ratio [OR] 4.22). This association was further boosted when sperm was found bilaterally (OR 6.70). Late failure rate (azoospermia) was 10.6% at mean time of 14.1 months and 23% for <2 million, at mean time of 15.7 months. When assessing predictors of late failure, intraoperative motile sperm bilaterally was a statistically significant protective factor on multivariate analysis (hazard ratio 0.22).

Vasovasostomy remains highly efficacious in treating obstructive azoospermia. Young patients, shorter obstructive intervals, and sperm identified intraoperatively predict improved outcomes. Clinicians can expect VV patency in 3 months and late failure within the first 2 years after surgery. However, patency rates, late failure rates, and kinetics vary by definition.