Intraoperative electrical stimulation of cavernosal nerves with monitoring of intracorporeal pressure in patients undergoing nerve sparing radical prostatectomy.

Abstract

To explore the utility of intraoperative cavernosal nerve stimulation in facilitating atraumatic nerve dissection during radical prostatectomy, and thus help predict postoperative erectile function. Fourteen patients (aged 51-72 years) underwent nerve-sparing radical retropubic prostatectomy (NSRRP); 10 were potent before surgery (group 1), and four had erectile dysfunction (group 2). A multi-acquisition system (MacLab/8e) with a Macintosh computer was used for real-time display and recording of intracavernosal pressure (ICP) during surgery. Nerves were stimulated with a bipolar probe (monophasic rectangular pulses, 10 mA, 20 Hz, 0.22 s) before and after removal of the gland. The follow-up consisted of interviews with patients and their partners' 12-18 months after treatment. The mean (sem) basal ICP of 8. 0 (2.0) cmH2O remained unchanged during nerve dissection. The mean increase in ICP during electrical stimulation was >50 cmH2O in seven potent patients (group 1) and was sustained as long as the nerve was stimulated. Postoperatively, these seven patients reported erections sufficient for sexual intercourse. However, the three remaining patients in group 1 had pressure rises of <30 cmH2O, of whom two reported partial erections and one reported total impotence postoperatively. The recovery time for erectile function was 6-12 months after surgery. Two patients from group 2 had transient increases in ICP to <40 cmH2O; one had an increase to 20 cmH2O and one had no response at all. All four patients remained totally impotent postoperatively. There were no complications. Intraoperative electrical stimulation of the cavernosal nerves with ICP monitoring before and after NSRRP is a safe and reliable method for documenting nerve continuity and its functional status. Patients who have normal preoperative erectile function and show an adequate rise in ICP upon electrical nerve stimulation during NSRRP will almost certainly be potent after surgery. This tool may be used to facilitate atraumatic nerve dissection during NSRRP.