Comparison of novel and manufacturer-recommended electrode placements for electromyography-based neuromuscular monitoring: a randomized, within-participant study

We compared a novel electrode placement (“Pattern Cross”) with the original (Pattern O–N) and revised (Pattern N–N) manufacturer-recommended placements for electromyography-based neuromuscular monitoring using Nihon-Kohden NM-345Y™ electrodes. In this single-center, randomized, blinded, within-participant study, 44 patients undergoing laparoscopic surgery were assigned to the Pattern O–N versus Pattern Cross ( n = 25) or Pattern N–N versus Pattern Cross ( n = 19); Cross was applied to one forearm and the comparator to the contralateral forearm. Monitoring was calibrated at 90° supination before forearm repositioning to 0° pronation. The primary endpoint was time from initial rocuronium administration to first post-tetanic count (PTC) appearance. After outlier exclusion, mean time to first PTC appearance did not differ between Pattern O–N and Cross (mean difference, 5 min; 95% confidence interval [CI], −3 to 12) or between Pattern N–N and Cross (−1 min; 95% CI, −7 to 4). Secondary endpoints were generally similar between Pattern N–N and Cross. Within-participant difference analysis showed marked delays or absent PTC detection with Pattern O–N or Pattern N–N in selected participants. Pattern Cross did not demonstrate superiority for the primary endpoint, but may help maintain stable recovery-signal detection during forearm pronation. Trial registration: UMIN-CTR, UMIN000053918, registered 20/03/2024.