Reduction in postoperative opioid requirement associated with use of the NSS-2® Bridge device, a disposable auriculo-nerve field stimulator, and factors affecting the response in cancer patients undergoing abdominal surgical procedures

Objective Determine the effect on opioid use after surgery with use of the NSS-2® Bridge device (NBD®) as a field nerve stimulator of the nerves innervating the ear for 5 days. Methods This was a prospective, randomized, double-blind, placebo-controlled trial investigating the effectiveness of the NBD® in reducing opioid (expressed as oral morphine equivalent; OME, mg) requirement in subjects undergoing abdominal surgery for cancer. A total of 53 subjects randomly assigned to either an active NBD® group or placebo group were included in the analysis. Secondary endpoints included pain using a verbal analogue scale (VAS, 0 = no pain to 10 = worst possible pain), time to ambulation, oral intake, first bowel movement, discharge from the hospital, and tolerability of the NBD®. Lastly, functional recovery rated using the 12-item Short Form Survey (SF12) assessed at three months. Results Use of the NBD® resulted in a 26% overall reduction in OME with no difference in pain level expressed as the area under the curve between postoperative day 1 to 5. respectively). This overall reduction accounts for a 6% reduction in OME in the patients undergoing laparoscopic surgery and a 39% reduction in OME and 25% reduction in pain in patients undergoing open surgery. The tolerability of the device was reported as excellent. Conclusions Cancer patients have been identified as a population at risk of developing opioid use disorders. This prospective, randomized, double-blind, placebo-controlled study, demonstrated that NBD® may be an effective alternative to the use of opioid postoperatively in patients undergoing abdominal surgery for cancer, especially in especially in patients undergoing open surgery and in elderly. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial NCT03555266 ### Funding Statement The study was funded in part by a grant from the UPMC Shadyside Foundation and the UPMC Department of Anesthesiology and Perioperative Medicine. Active and placebo NSS-2 Bridge devices were provided free of charge by Innovative Health Solutions (IHS), Versailles, IN, USA. IHS did not take part in the development of this article. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Institutional Review Board of the University of Pittsburgh (STUDY19040260) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript