THE RELATIONSHIP BETWEEN THE VAS VOLUME AND THE ANATOMIC SIZE OF THE VAS-DEFERENS

The anatomic sizes of 210 vas segments from 107 volunteers of vasectom y were measured by computerized image graphic technique with microphot ography. The mean equivalent-round, outer and inner diameters of the v as were 2.17 +/- 0.20 mm and 0.56 +/- 0.08 mm, respectively. The calcu lated thickness of vas wall was 0.82 +/- 0.21 mm. The maximal volumes of 124 vas segments (1 cm in length) were tested by injecting colored solution into vas lumen until vas rupture. The mean rupture volume of 1 cm vas lumen was 0.05 +/- 0.007 mL. A significant influence of the t hickness of vas wall (p <0.05) and body height (p <0.05) on the ruptur e volume was noticed in stepwise regression analysis. A tunnel-like ru pturing pattern was observed in morphological observation. The obtaine d rupture volume provides a security line in determining the injection volume of occlusive material or the size of the implanted contracepti ve device. (C) 1997 Elsevier Science inc. All rights reserved.