Width of spared neurovascular bundle after robot-assisted laparoscopic prostatectomy in patients with prostate cancer: is it a reliable factor for predicting postoperative sexual outcome?

Abstract

To investigate the relationship between the width of spared neurovascular bundle (NVB) measured during robot-assisted laparoscopic prostatectomy and postoperative sexual outcomes. Patients with localized prostate cancer with erectile hardness score ≥2 (N = 105) who underwent NVB-sparing robot-assisted laparoscopic prostatectomy were included. Patients were divided into three groups [first (Q1) vs. second and third (Q2-3) vs. fourth (Q4) quartile] according to width of spared NVB measured with a flexible ruler after prostate removal. Preoperative and postoperative sexual function was evaluated according to erectile hardness score and Expanded Prostate Cancer Index Composite questionnaires. The proportion of patients with postoperative erectile hardness score ≥2 at postoperative 6 months was as follows: 38.9% (Q1), 48.6% (Q2–3), and 83.3% (Q4) (P = 0.016). The preoperative/postoperative 6-month sexual function score was 40.7/16.9 (Q1), 48.1/19.0 (Q2–3), and 51.2/28.1 (Q4). Postoperative sexual function was significantly associated with preoperative sexual function in Q4 (P = 0.006) and Q2–3 (P = 0.030) but not in Q1. On multivariate analysis, the width of spared NVB was a significant predictor for postoperative 6-month erectile hardness score ≥2. Limitation includes selection bias and short follow-up duration. Not only the performance but also the degree and quality of NVB sparing thought to be important for postoperative sexual function. Measurement of the width of NVB during surgery could be an easy intraoperative method for assessing the quality of NVB sparing.