A randomized phase 3 study of intraoperative cavernous nerve stimulation with penile tumescence monitoring to improve nerve sparing during radical prostatectomy

Purpose: We determine if mapping of the cavernous nerve during radical pros tatectomy using intraoperative cavernous nerve stimulation with tumescence monitoring results in improved erectile potency compared to conventional ne rve sparing. Materials and Methods: A prospective, randomized, single blinded study was performed on 61 patients at 6 centers. Patients had elected to undergo nerv e sparing prostatectomy and had normal preoperative erectile function docum ented by the Sexual Function Inventory Questionnaire (SFIQ) and RigiScan pa rallel to testing. Patients were randomized between conventional nerve spar ing and nerve sparing assisted by the CaverMap Surgical Aid. In all patient s neural continuity was assessed immediately after prostate removal by prox imal cavernous nerve stimulation. All patients were blinded according to th eir allocation cohort. Results: At 1 year there was substantial improvement in erectile function i n the CaverMap group as measured by RigiScan. This group had a mean of 15.9 minutes of greater than 60% nocturnal tumescence compared to 2.1 minutes i n the conventional nerve sparing group (p <0.024). By SFIQ there was a nons ignificant trend to improved potency in the CaverMap group (71% versus 62%, p = 0.17). Of patients who had bilateral, unilateral and no response to st imulation after resection erectile function assessed by SFIQ recovered in 6 8%, 27% and 0%, respectively (p = 0.016). Conclusions: CaverMap assisted prostatectomy led to improved erectile funct ion as assessed by RigiScan testing with no associated adverse events. A re sponse to stimulation immediately after removal of the prostate accurately predicted return of erectile function.