Neurovascular Bundle Stimulation During Robot-Assisted Radical Prostatectomy (NVB Stym-RARP)

Selective Electrical Stimulation of the Neurovascular Bundles During Robot-Assisted Radical Prostatectomy for Intraoperative Monitoring of Erectile Function

This prospective first-in-human feasibility study will evaluate the safety and feasibility of selective electrical stimulation of the neurovascular bundles (NVBs) during nerve-sparing robot-assisted radical prostatectomy (RARP). 20 adult patients with localized prostate cancer, normal preoperative erectile function (IIEF >20), and planned bilateral or unilateral nerve-sparing surgery will be enrolled.

During surgery, a custom stimulation probe will deliver low-intensity electrical stimulation to the neurovascular bundles before and after prostate removal. Physiological responses, including penile rigidity, corpus cavernosum electromyography (CC-EMG), penile temperature, galvanic skin response, peripheral pulse, and other intraoperative signals, will be recorded to assess preservation of neurovascular function. The stimulation parameters remain below established safety thresholds for neural tissue.

The study aims to determine whether selective neurovascular bundle stimulation is a safe and feasible method for intraoperative functional monitoring during RARP and to generate preliminary data for future clinical studies.

Study Overview

• Status: Enrolling by invitation
• Conditions: Histologically Confirmed Localized Prostate Cancer; Scheduled to Undergo Robot-assisted Radical Prostatectomy With Planned Unilateral or Bilateral Nerve-sparing Surgery
• Intervention / Treatment: Device: Selective Neurovascular Bundle Stimulation Probe

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Slovenia
  • Ljubljana, Slovenia, 1000
    • UMC Ljubljana

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Experimental: Selective Neurovascular Bundle Stimulation; Participants undergoing nerve-sparing robot-assisted radical prostatectomy will receive intraoperative selective electrical stimulation of the left and/or right neurovascular bundles using an investigational stimulation probe. Physiological responses will be recorded before and after prostate removal.

Device: Selective Neurovascular Bundle Stimulation Probe; An investigational sterile stimulation probe will be used to deliver biphasic charge-balanced electrical stimulation to the neurovascular bundles during robot-assisted radical prostatectomy. Stimulation will be performed intraoperatively before and after prostate removal using stimulation parameters that remain below established neural injury thresholds. Physiological responses will be recorded to evaluate neurovascular function.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety and technical feasibility of intraoperative selective neurovascular bundle stimulation	The primary outcome is the safety and technical feasibility of intraoperative selective neurovascular bundle stimulation, assessed during surgery by successful completion of the stimulation procedure without device-related serious adverse events or clinically significant interference with the planned robotic-assisted radical prostatectomy.	During the surgical procedure (intraoperative assessment).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Successful acquisition of intraoperative physiological monitoring signals	Successful recording of physiological responses during selective neurovascular bundle stimulation, including corpus cavernosum electromyography (CC-EMG), penile rigidity, penile temperature, galvanic skin response, and peripheral pulse measurements.	During surgery
Physiological responses to neurovascular bundle stimulation	Characterization and comparison of physiological responses elicited by selective neurovascular bundle stimulation before and after prostate removal.	During surgery (before and after prostate removal)
Investigational device performance	Evaluation of successful deployment, positioning, stimulation, signal acquisition, and removal of the stimulation probe without device malfunction or procedural failure.	During surgery
Recovery of erectile function	Recovery of erectile function assessed using the International Index of Erectile Function (IIEF) questionnaire or another validated patient-reported outcome measure.	3, 6, and 12 months after surgery

Collaborators and Investigators

• Sponsor: University Medical Centre Ljubljana

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): August 30, 2028
• Study Completion (Estimated): August 30, 2028

Study Registration Dates

• First Submitted: July 20, 2026
• First Submitted That Met QC Criteria: July 20, 2026
• First Posted (Actual): July 23, 2026

Study Record Updates

• Last Update Posted (Actual): July 23, 2026
• Last Update Submitted That Met QC Criteria: July 20, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: localized prostate cancer; robot-assisted radical prostatectomy; peripheral nerve stimulation; standard-of-care; neurovascular function; unilateral or bilateral nerve-sparing surgery; neurovascular bundles; prostate removal; intraoperative selective biphasic charge-balanced electrical stimulation
• Other Study ID Numbers: 0120-138/2024-2711-6

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No