Association between the presence of sperm in the vasal fluid during vasectomy reversal and postoperative patency in identified retrospective studies. The summary estimate was calculated using a random effects model. Exponentiation of the pooled log(OR) plotted above yielded an unadjusted OR of 4.1 (95% CI: 2.3 to 7.3). The pooled log(OR) calculated using a fixed effect model was 1.5 (95% CI: 1.1 to 1.9) with a corresponding OR of 4.3 (95% CI: 2.9 to 6.4). Assessment of heterogeneity: Q = 3.4, df = 5, p = 0.6, I2 = 22%. CI = confidence interval, OR = odds ratio, P = patent.