Intraoperative electromyographic monitoring of the recurrent laryngeal nerve in reoperative thyroid and parathyroid surgery

Abstract

Background: Injury to the recurrent laryngeal nerve (RLN) is a rare complication of initial thyroid and parathyroid surgery, but the prevalence is much higher in the reoperative setting. The use of continuous, intraoperative electromyographic monitoring of the RLN has been suggested to improve the safety of cervical explorations.

Methods: Outcomes of a group of reoperative thyroid and parathyroid cases that used EMG monitoring with endoscopically applied hook-wire electrodes were compared with a group of cervical reoperations without monitoring. Office laryngoscopy (indirect or fiberoptic) was used to evaluate and follow suspected RLN complications.

Results: Electromyography was used in 52 cervical reexploration procedures. Patients averaged 1.8 previous explorations (range, 1-7 explorations) and underwent procedures for parathyroid (31%) and/or thyroid (77%) disease (overall, 72% malignant). The non-monitored group had 59 patients with similar characteristics. Only 1 permanent nerve complication in each group was unintended (electromyography, 1.9%; non-electromyography, 1.7%). Seven false-negative and 2 false-positive electromyographic findings occurred. No complications resulted from placement of the electromyography electrodes.

Conclusions: Intraoperative electromyographic monitoring of the RLN in reoperative neck surgery can be performed safely but did not decrease RLN complications in this study. Experience and routine nerve exposure remain crucial to the minimization of RLN complications.