Dynamics of loss and recovery of the nerve monitoring signal during thyroidectomy predict early postoperative vocal fold function.

Abstract

The characteristics of segmental type 1 and global type 2 injuries to the recurrent laryngeal nerve (RLN) and the extent and dynamics of nerve recovery are poorly understood. This investigation of 785 patients who underwent thyroidectomy under continuous intraoperative nerve monitoring aimed at exploring the dynamics of loss and recovery of the nerve monitoring signal and its relationship to early postoperative vocal fold palsy. Persistent complete loss of signal and signal recovery <50% identified all (based on 12 and 4 patients with type 1 injuries) or most (based on 9 of 12 and 4 of 6 patients with global type 2 injuries) early unilateral vocal fold palsies. Signal recovery ≥50% (based on 7 patients) always signified normal vocal fold function. These data, including the observation that global type 2 injuries may entail less severe nerve injury, require validation in independent series before being adopted more widely. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1144-E1151, 2016.