Microsurgical nerve graft repair of the ablated cavernosal nerves in the rat

Erectile dysfunction is a significant complication of radical pelvic surgery in men. Using the rat as an experimental model, we investigated the feasibility of repairing surgically ablated cavernosal nerves. Known fertile male Sprague-Dawley rats were randomly divided into three surgical groups of 30 animals (60 study nerves) per group consisting of nerve ablation, immediate nerve reconstruction, and control groups. The nerve ablation group had 5-mm sections of the cavernosal nerve excised bilaterally. The nerve graft group had 5-mm sections of the cavernosal nerve excised bilaterally, followed by immediate microsurgical reconstruction with an autologous interposition nerve graft utilizing the ipsilateral genitofemoral nerve bilaterally. The anastomoses were performed with 10-O nylon sutures at 16 to 25x magnification. The control group underwent sham operations with the cavernosal nerves being exposed only. Erectile function was evaluated at 1, 2, 4, and 6 months postoperatively. Return of erectile function was defined as tumescence of the corporal bodies with application of direct electrical stimulation (3 V of 5 msec pulses at 20 Hertz) to the proximal cavernosal nerves. The 4- and 6-month electrical stimulation studies resulted in tumescence from 65 and 75% of the grafted nerves, which represented a significant difference compared to the ablated group 11 and 5%, respectively (P less than 0.001 at 4 and 6 months). Behavioral copulatory studies, performed prior to electrical stimulation testing, corresponded closely with the results of electrically induced tumescence. We conclude that in this experimental model immediate nerve graft repair appears to be a successful method of salvaging erectile function when the cavernosal nerves have been divided.