Neurovascular Bundle Stimulation During Robot-Assisted Radical Prostatectomy

Radical prostatectomy is a standard treatment for localized prostate cancer. Although nerve-sparing robot-assisted radical prostatectomy (RARP) improves functional outcomes, postoperative erectile dysfunction remains common because of injury to the cavernous nerves within the neurovascular bundles (NVBs). Currently, surgeons have limited methods for objectively assessing functional nerve integrity during surgery.

This prospective feasibility study investigates selective electrical stimulation of the NVBs as an intraoperative monitoring technique during RARP. The study will enroll 20 adult patients with localized prostate cancer, normal baseline erectile function (IIEF >20), and planned nerve-sparing surgery.

A custom-designed stimulation probe based on the selective stimulation model described by Pečlin and Rozman will be applied intraoperatively to the left and right NVBs before and after prostate removal. Medical-grade electrodes will deliver biphasic charge-balanced electrical stimulation within established safety limits that avoid neural tissue injury. The probe will be sterilized using electron beam irradiation.

During stimulation, physiological responses including penile rigidity, corpus cavernosum electromyography (CC-EMG), penile temperature, galvanic skin response, peripheral pulse measurements, and ambient temperature will be recorded. These measurements will be analyzed to assess neurovascular function and compare responses before and after prostate removal.

The primary objective is to evaluate the safety and technical feasibility of selective NVB stimulation during RARP. Secondary objectives include characterization of physiological responses to stimulation and assessment of the potential utility of this technique for intraoperative nerve preservation. Results from this pilot study will provide preliminary evidence to support future larger clinical studies evaluating functional outcomes after nerve-sparing prostatectomy.

Inclusion criteria

• male participants aged 18 years or older;
• histologically confirmed localized prostate cancer;
• scheduled to undergo robot-assisted radical prostatectomy (RARP) with planned unilateral or bilateral nerve-sparing surgery;
• normal preoperative erectile function, defined as an International Index of Erectile Function (IIEF) score >20;
• able and willing to provide written informed consent.

Exclusion criteria

• nerve-sparing surgery is not indicated;
• previous radical prostatectomy or pelvic surgery likely to alter neurovascular bundle anatomy;
• severe pre-existing erectile dysfunction, defined as an IIEF score ≤20;
• contraindication to robot-assisted radical prostatectomy;
• any medical, psychiatric, or other condition that, in the opinion of the investigator, could compromise participant safety, interfere with study participation, or affect interpretation of the study results.