Neurovascular bundle block as predictor of postoperative erectile function after radical prostatectomy

Abstract

We assessed audiovisually induced erections after nerve block of the neurovascular bundle during prostate biopsy. We evaluated neurovascular bundle nerve block to mimic non-nerve-sparing radical prostatectomy in an experimental setup. Patients undergoing a transrectal ultrasound-guided prostate biopsy were randomized to bilateral injection of 5 ml ropivacaine hydrochloride 0.75% or NaCl 0.9% into the neurovascular bundle. The patients completed the International Index of Erectile Function 5-item questionnaire (IIEF-5) questionnaire, and a detailed patient history was obtained. A routine prostate biopsy was performed. Thereafter, patients were exposed to 60 min of audiovisual stimulation. Erections were recorded using a Rigiscan-Plus device. A total of 11 patients were randomized. Five patients received NaCl (group 1) and six patients ropivacaine (group 2). Patient characteristics were comparable in terms of age (group 1: 59.8 y; group 2: 61.8 y), mean PSA (4.1 vs 4.7 ng/ml), mean IIEF-5 score (20.5 vs 22) and risk factors for erectile dysfunction, respectively. Patients of group 1 showed significantly stronger and longer erections after audiovisual stimulation than patients in group 2. Patients with bilateral infiltration of saline solution to the neurovascular bundle showed significantly stronger erections than patients receiving local anesthesia of the neurovascular bundle. Thus, this experiment might serve as a model to assess postoperative erectile function after a unilateral nerve-sparing radical prostatectomy.