Comparison of two electromyographical endotracheal tube systems for intraoperative recurrent laryngeal nerve monitoring: reliability and side effects

Background Recurrent laryngeal nerve (RLN) monitoring systems should be reliable and safe. Monitoring via electromyographical systems on an endotracheal tube (ETT) is widely spread. The MagStim (TM) system consists of an adhesive electrode to be fixed on an endotracheal tube. The Xomed (TM) endotracheal tube provides integrated electrodes. Reliability and side effects had never been compared. As both systems have very different morphological properties, we hypothesized that there might be differences in reliability and the incidence of side effects. Methods In a retrospective quality management analysis of 118 patients (MagStim (TM) electrode, 57 patients; Xomed (TM) ETT, 61 patients), we compared laryngeal side effects according to the Chilla score and detection rate of the RLN. Results Both systems had comparable detection rates of the RLN above 95%. Both electrode systems seemed to have similar reliability. Difficulties to detect the nerve were observed in seven patients (four with MagStim, three with Xomed). In the group with the Xomed (TM) ETT, significantly less mild laryngeal side effects were observed. Conclusion Both MagStim (TM) and Xomed (TM) ETT were reliable in detecting the RLN. The Xomed T ETT, however, might cause milder laryngeal side effects compared with the MagStim (TM) electrode.