To confirm the distribution of functional nerves involved in erectile function at the posterior of the prostate base, intraoperative nerve stimulation was performed during robot-assisted radical prostatectomy (RARP)

Several points at the posterior of the prostate and the posterolateral typical neurovascular bundle (NVB) were electrically stimulated at the level of the prostate base during RARP in patients with clinically localized prostate cancer. The prostate pedicle (PP), medial side of the PP (MPP), Denonvilliers’ fascia (DF), and typical NVB were stimulated using bipolar electrodes. The changes in pressure at the middle of the urethra were measured using an inserted balloon-catheter to detect the increase in cavernosal pressure.

Although the study included only 12 patients, each stimulation of the PP, MPP, and NVB induced evident urethral pressure responses in all patients. The median amplitude of the pressure responses was 5.49 (IQR 3.11-8.42), 6.00 (IQR 3.70-8.30), and 3.22 (IQR 2.48-7.19) cm H2O at the PP, MPP, and NVB, respectively. The amplitude of responses at the PP and MPP was not small compared with the responses at the typical NVB. Stimulations at the DF induced unstable weak urethral response alone or no response in all patients.

We showed that electrostimulation of the PP and MPP increases the cavernosal pressure similar to the typical NVB stimulation. These findings indicate that maximal preservation of the tissues at the posterior area of the prostate base can contribute to optimal recovery of postoperative erectile function after nerve-sparing RARP.