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 receive either an active NBD (NBD group) or placebo NBD (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.