Intraoperative Nerve Monitoring During Robotic-assisted Radical Prostatectomy

Study design:

This is a single center, randomized, single blinded, prospective, clinical trial. The study population will comprise of 100 men that will undergo either a non-nerve sparring or unilateral-nerve sparring RARP. This means that the preoperative evaluation has suggested that it will not be possible to preserve the cavernous parasympathetic nerves lying in the fascia on either side of the prostate gland during surgery (called bilateral-nerve sparring). Despite the term, non-nerve sparring surgery, the surgeon will still attempt to preserve the somatic fibers of the pudendal nerve as best possible. However, due to the extent of cancer tissue the surgeon will generally need to operate closer to the pudendal nerve then when performing bilateral-nerve sparring surgery. So, the somatic fibers of the pudendal nerve are more likely to be severed. The same is the case on one side when performing unilateral surgery.

The treatment group will consist of 50 subjects that will undergo nerve monitoring during RARP. Results will be compared to a control cohort consisting of 50 patients that will undergo contemporary RARP.

Aside from the usage of nerve monitoring in the intervention-group, all procedures and care from admission to the hospital through discharge will be standard of care for subjects in both the control and Intervention-group.

Baseline evaluation and collection of data:

Patients will be screened for eligibility on the phone, and if eligible and they accept they will be scheduled to a visit at the hospital where the following data will be registered for all participants prior to surgery:

• Age at time of surgery
• Known co-morbidity
• Body Mass Index (BMI)
• Medicine status
• Smoking
• Partner status
• Level of education
• Employment Clinical status
• Clinical stage (cT-staging)
• Gleason score
• Prostate specific antigen (PSA)

Prior to surgery participants will also have answered the questionnaires listed either prior to or during the first visit and have undergone an MRI and the bulbocavernosus-reflex test:

• ICIQ (International Consultation on Incontinence Questionnaire) form about incontinence symptoms
• Danish Prostate Symptom Score (DAN-PSS)
• International Prostate Symptom Score (IPSS)
• International Index of Erectile Function (IIEF) score
• Erection Hardness Scale (EHS) score
• Presence or absence of bulbocavernosus-reflex. The physician test for this by shortly squeezing the penis while observing if the urethra retracts or the anal sphincter contracts. The test is not painful and only takes a few seconds.
• Magnetic Resonance Imaging (MRI) scan with measurements of the urethral length and width, and prostate volume along with other specific anatomical structures in relation to the urethra. Contrast agents will not be applied.

Intraoperative data:

• Contraction of the sphincter musculature during stimulation via the nerve monitoring system before removal of the prostate gland
• Contraction of the sphincter musculature during stimulation via the nerve monitoring system after removal of the prostate gland.
• Blood loss
• Non- or unilateral nerve sparring
• Lymph node dissection
• Total surgical time
• Sphincter lesion
• The surgeon's subjective prediction whether the patient will return to continence postoperatively

During the procedure, through discharge and before follow-up regime begins, the following data points will be collected:

• Time to removal of catheter
• Leakage of the anastomosis
• Stricture.
• Other adverse effects
• Pathologic cancer stage (pT-stage)
• Pathologic Gleason score
• Status of surgical margins

Follow-up evaluation.

Subjects will be evaluated 14 days after catheter removal and at standard clinical controls at 3, 6 and 12 months. The following questionnaires are answered at every visit:

• International consultation on Incontinence Questionnaire (ICIQ) for incontinence,
• Danish Prostate Symptom Score (DAN-PSS)
• International Prostate Symptom Score (IPSS)
• International Index of Erectile Function (IIEF) and Erection Hardness Scale (EHS).

During the last 3 visits subjects also answers a fluid intake/output questionnaire and hand in the results of a 24-hour pad test. In addition to the questionnaires the patients will also undergo an MRI and a bulbocavernosus reflex test 12 months postoperative.