Neurovascular bundle size measured on 3.0-T magnetic resonance imaging is associated with the recovery of erectile function after robot-assisted radical prostatectomy

Background and objective: Erectile dysfunction is one of the complications occurring after radical prostatectomy (RP), and recovery of erectile function is quantitatively related to the preservation of the neurovascular bundles (NVB). We evaluated the significance of NVB area on functional outcomes after RP. Materials and methods: Preoperative magnetic resonance imaging was performed on 141 patients who underwent bilateral, nerve sparing, robot-assisted RP for clinically localized prostate cancer (clinically T2N0M0 on magnetic resonance imaging) and were evaluated at least 12 months after surgery. NVB area was measured as a region of interest that coincided with the outline of the maximum area of the posterolateral region of the prostate on T2-weighted axial imaging. Factors associated with functional outcomes were evaluated using logistic regression analysis. Results: Of 141 patients, 36 patients (25.5%) had no preoperative potency (group 1), 66 patients (46.8%) recovered potency (group 2), and 39 patients (27.7%) did not recover potency (group 3). Although the mean age of the entire cohort was 65.4 years, the mean age of group 1 was greater than groups 2 and 3 (P = 0.001). The NVB area of group 2 was larger than those of groups 1 and 3 (P = 0.001). Potency evaluations involved 105 patients (74.5%; groups 2 and 3), and patients with pre-existing erectile dysfunction were excluded. The median time to potency recovery was 3.0 months after surgery. The multivariable analysis revealed that the NVB area was the only significant factor predictive of potency recovery. Conclusions: The NVB area in the posterolateral region of the prostate is an independent factor for predicting potency recovery. The degree of postoperative erectile function can be predicted based on the preoperative NVB area. (C) 2017 Elsevier Inc. All rights reserved.