Association between the length of the vas deferens excised during vasectomy and the risk of postvasectomy recanalization.

OBJECTIVE: To evaluate the association between the length of the vas deferens excised during vasectomy and the risk of recanalization.
DESIGN: Nested case-control study.
SETTING: Hospital-based Family Planning Clinic in Quebec City (Canada). PATIENT(S): Among 870 vasectomized men, all 47 cases of spontaneous recanalization and 188 controls whose first semen analysis showed either azoospermia (controls A) or <1 x 10(6)/mL nonmotile sperm (controls B). MAIN OUTCOME MEASURE(S): Spontaneous recanalization defined as a semen analysis showing any motile sperm 6 weeks or more after vasectomy. RESULT(S): Individual vas segments excised ranged from 5 to 20 mm in 227 (97%) of the 235 participants. The mean +/- SD of the average of both segments for each man was 12 +/- 4 mm, identical in cases and in controls. In cases and controls A, the risk ratio (95% confidence interval [CI]) of recanalization with an average of segments of <10 mm and 10-14 mm was 0.6 (0.1-2.0) and 0.6 (0.2-1.6) when compared to 15 mm or more, respectively. In cases vs. controls B, the risk ratio of recanalization was 1.6 (0.4-7.7) and 0.6 (0.2-1.7), respectively. CONCLUSION(S): In this cohort, there was no association between the length of vas segment excised and the risk of recanalization.