Biomechanical properties of normal and varicose internal spermatic veins.

To investigate possible differences in biomechanical properties between varicose spermatic veins and controls. During surgery on 12 patients for grade 3 left-sided varicocele testis, 2 cm of the vein was obtained for comparison with: (i) samples of the left internal spermatic vein taken from the same anatomical localization from 8 patients without scrotal disease, and (ii) samples from the right internal spermatic vein from 7 other patients also without scrotal disease. The biomechanical properties of ring-shaped venous specimens were investigated by loading the specimen at a constant deformation rate until rupture. The relative amounts of collagen in the specimens were determined as the contents of hydroxyproline. There was a significant difference between varicocele testis/right spermatic vein in UC (unit collagen), F-max (maximum strength), Strain (ultimate extensibility) and E-fail (relative failure energy), but not in LD (diameter) and Tan-a (stiffness of the specimen). There were no significant differences between left and right spermatic vein in LD, UC, F-max, Strain, Tan-a and E-fail. There was a significant difference in LD between varicocele testis/left spermatic vein, but no relationship in UC, F-max, Strain, Tan-a and E-fail. Biomechanical analyses of the spermatic veins from patients operated for varicocele seem to support the hypothesis that a difference in biomechanical properties plays a part in the development of varicocele because a significant increase in extensibility of varicocele samples was found compared with normal right spermatic vein samples.