Intraoperative Nerve Monitoring During Robot-assisted Laparoscopic Prostatectomy

Study Design:

This is a single surgeon, single institution prospective post-market study of patients undergoing a robotic-assisted laparoscopic prostatectomy (RALP) with intraoperative nerve monitoring of pelvic nerves using the ProPep Nerve Monitoring System. The treatment group will consist of 80 subjects (with 69 anticipated to be evaluable) undergoing RALP with intraoperative nerve monitoring (IONM). This will be compared to a consecutive group of contemporary control cohort patients who have underwent RALP without nerve monitoring by the same single surgeon.

Baseline Evaluations and Data Collection:

Pre-operative baseline evaluations and data collection will be used to determine eligibility for enrollment and to document subject clinical status prior to surgical procedure. This information is recorded on the Screening case report forms (CRF).

The following data will be collected at screening/baseline:

• Medical History including Gleason score at biopsy, and clinical stage (cT, TNM 2002);
• Physical examination;
• Demographic information;
• Current symptoms;
• Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP) Questionnaire;
• SHIM Questionnaire;
• Use of any drugs for erectile dysfunction ;
• Confirmation of inclusion and exclusion criteria.

Surgical Procedure The surgical procedure should be completed according to site-specific standards. The following is a general overview of the surgical procedure for this study. The daVinci Surgical System must be used. Additional instrumentation necessary to perform the procedure is determined by the surgeon.

The Pep Electrode Introducer facilitates the introduction of the needle electrodes into the pelvis. The electrodes are initially placed in the levator muscle near the apex of the prostate in the area of the nerve bundles prior to the pedicle dissection to identify the perineal branches of the pudendal nerve. Prior to posterior dissection of the apex of the prostate, the needle electrodes are removed from the levator muscle and moved to the external urethral sphincter to identify the deep (muscular) branch of the perineal nerves. Action potentials are measured by the Pep Monitor.

Signals are induced in the nerve(s) of interest by stimulating the tissue surrounding the nerve(s) along the presumed nerve pathway with a low level electrical current. The low level current is delivered through the conventional bipolar instrument used during robotic surgery and when delivered close to a nerve it triggers and action potential in the nerve that is displayed on the Pep Monitor. The Pep Control Switch is used to switch the bipolar instrument between cautery mode and stimulation mode. The closer the bipolar instrument is to the nerve being located, the larger the amplitude of the action potential displayed by the Pep Monitor.

Nerves will be identified with the device prior to pedicle and apical dissection to establish nerve location. Nerve monitoring may be used through the course of dissections to confirm nerve location. Post-dissection readings will be collected after specimen removal to confirm the integrity of the preserved nerve tissue at the end of the case.

During the procedure and through hospital discharge the following data points will be collected:

• Type of nerve sparing - none, partial, and bilateral;
• Prostate size;
• Estimated blood loss and transfusion(s);
• Method of dissection (transperitoneal anterior, posterior, extraperitoneal, or lymph node dissection);
• Gleason score at radical prostatectomy;
• Pathological stage (nT);
• Positive surgical margin rate (PSM);
• Total robotic and surgical time;
• Total time for device deployment;
• Hospital admission / discharge dates; and
• Adverse events.

Postoperative care will be according to the site-specific standard of care.

Follow-up Evaluation and Data Collections:

Subjects will be followed post-operatively at catheter removal (typically 1 week), 1 month (±2 weeks), 3 months (±3 weeks), 6 months (±1 month), and 12 months (±1 month) following the procedure. Data will be collected on the appropriate follow-up Case Report Forms (CRFs). The CRFs for each of the follow-up data collection points will be supplied to the subjects upon their discharge from the hospital following their procedure. Research assistant will call subjects the week prior to the due date to remind subjects to fill in and mail back (via pre-addressed, stamped envelopes supplied with CRFs) appropriate CRF. Site specific standard of care will be followed post-operatively.

The following data and testing will be completed at each follow-up visit:

• Current symptoms;
• Modified EPIC-CP Questionnaire (question 3 and 4);
• SHIM Questionnaire;
• Use of any drugs for erectile dysfunction; and
• Adverse events (AE).

Contemporary Control Cohort:

As the procedures for the prospective cohort are standard of care at the investigators institution, the investigator will have all of the same measures for the contemporary control cohort that he has for the for the prospective cohort. Each prospective subject will be matched to two selected subjects in the contemporary control cohort by biopsy Gleason score (6 vs. 7 vs. 8-10), nerve-sparing status (yes/no), type of nerve sparing (unilateral or bilateral) and age (within 5 years). The contemporary control cohort will draw from consecutive patients who have undergone RALP in the previous two years (2012-2014) that did not have IONM. The investigator will not record AEs for this contemporary control cohort as the investigator is only interested in collecting AEs data potentially related to the use of the IONM.