Farber NJ, et al. - Researchers conducted a retrospective cohort study including 429 patients with obstructive azoospermia who underwent vasovasostomy (VV), in order to determine the timing of patency and late failure (secondary azoospermia) after VV using standardized kinetics definitions. They defined patency as any sperm return to the ejaculate; and > 2 million total motile sperm (TMS) in ejaculate. The “any sperm” vs “> 2 million TMS” groups had mean time to patency of 3.25 months vs 5.29 months. Outcomes suggest that for obstructive azoospermia, vasovasostomy remains highly efficacious treatment option. Improved outcomes were observed in correlation with young patients, shorter obstructive intervals, and sperm identified intraoperatively. VV patency can be expected in 3 months and late failure within the first 2 years after surgery. However, variation was evident in patency rates, late failure rates, and kinetics in correlation with the definition.