Further evidence of venous outflow restriction during erection.

To elucidate the effect of venous outflow restriction during erection, we studied eight dogs during artificial saline perfusion of the penis with and without neurostimulation to induce erection. With the infrarenal aorta clamped temporarily, saline infusion rates of 0.9 and 1.9 ml/min raised the mean intracorporeal pressure to 34 and 42 cm H2O, respectively, before stabilisation or return to baseline. When cavernous nerve stimulation was initiated, the mean intracorporeal pressure rose to 124 and 184 cm H2O (with infusion rates of 0.9 and 1.9 ml/min respectively) to induce full erection. Our results show that venous outflow restriction takes place during erection and that it is necessary not only to induce full erection but also to maintain it. Evaluation of venous competence is therefore essential during the investigation of impotence.