The role of the neurometer CPT/C in sacral neuromodulation

The aim of the current research project was to study the role of the Neurometer^® as a tool to predict responders to sacral neuromodulation therapy (SNM).

This was a prospective, open study in male and female patients, aged 18 and over with voiding dysfunction [non-obstructive retention and/or frequency/ urgency syndrome]. The first group underwent a screening test to evaluate percutaneous nerve functions (PNE) and to determine whether they are candidates for SNM with the InterStim^®. Prior to PNE testing, all patients were evaluated with the pain tolerance test (PTT) using the electro-diagnostic Neurometer^® CPT/C device. An InterStim^® implant was placed in patients who were responders to PNE testing underwent. On the other hand, non-responders underwent a staged implant placement. The second group consisted of patients who already had InterStim^® implanted for voiding dysfunction. During the routine office follow-up, the patients implanted with Interstim^® underwent a PTT using the Neurometer^® CPT/C device. All the testing using the Neurometer CPT/C was performed on the day of the PNE for the first group, and the day of the routine follow-up visit for the second group. All of the results for the Neurometer^® testing were kept blinded from the PNE results, and those of the outcome of the follow-up visit. The study received approval by the Research Ethics Board of the University Health Network (No. 14-8196).

We recruited a total of 123 patients. The results presented here include 110 patients who completed the study, 48 of whom were in the first group, and 62 in the second group. The statistical analysis used was as follows: Group 1: Simple linear regression analysis and the linear discriminate analysis were preformed. It was found that for patients without the InterStim^® implant with a combined CPT/CPD of 800 and above, the Neurometer^® could predict the test screening results with an accuracy of 71%. Group 2: Same analysis and tests were conducted for patients with the InterStim^® implant, and the results showed that if the patient had a combined CPT/CPD of 600 and above, the Neurometer^® could predict the patients satisfaction or dissatisfaction with an accuracy of 72%.

Neurometer^® may play a role in predicting test trial positive responders and patient satisfaction after the placement of InterStim^® implant.