Cavernous nerve grafts restore erectile function in denervated rats

Although potency can be preserved in most men following radical prostatectomy, in some patients one or both cavernous nerves must be sacrificed in order to excise all tumor. For these patients we have considered nerve reconstruction at the time of surgery using an interposition nerve graft. This possibility has been tested in a rat model. Animals were divided into three groups. In the sham control group, a pelvic exploration was conducted without division of the cavernous nerves. In the nerve ablation group, a five mm. segment of cavernous nerve was excised. In the graft group, five mm. of cavernous nerve was excised bilaterally and replaced with an interposition graft of genito-femoral nerve. At one month intervals postoperatively animals from each group underwent mating tests to determine potency; the ratio of vaginal intromission to unsuccessful mounts (I/M ratio) was determined. Following the mating tests the animals were re-explored and attempts were made to stimulate erections electrically via the pelvic nerve. Results at two months show the I/M ratio of the rats with grafts (0.05) and the nerve ablations (0.14) are low compared with the sham operated animals (1.0). By month four the graft group (0.89) has approached the sham group (0.91) while the ablation group (0.18) remains unchanged (p less than .05). Electrical stimulation at month two produced no erections in the nerve ablated or the grafted rats and 100% erections in the sham-operated animals. At month four, 50% of the rats with grafts, 10% of the nerve ablated animals, and 100% of the intact animals produced erections upon electrical stimulation (p less than .05). These results suggest that cavernous nerve grafting in rats can be successful in restoring potency after surgical injury. Application of these techniques to man may be indicated.