Intraoperative recording of laryngeal adduction reflex (LAR) in IV ventricle tumor removal: Case report

Abstract

The laryngeal adductor reflex (LAR) represents the thyroarytenoid muscle response to electrical, mechanical or chemical stimulation of the laryngeal mucosa and is been considered to be a mechanism of laryngeal protection, preventing material from inappropriately entering the upper airway. The intraoperative recording of LAR has been recently proposed in patients undergoing thyroid and cervical spine surgeries. In the last years, intraoperative neurophysiology (IN) has been extensively applied in the surgery of IV ventricle tumors in children. In particular, brainstem mapping (BSM) and corticobulbar tract (CBT) monitoring have demonstrated to be effective in order to reduce the risk of severe post-operative neurologic sequelae. IN techniques (BSM and CBT monitoring) were applied during the removal of a large IV ventricle tumor in a 4 yrs. old child under TIVA/TCI anesthesia. LAR was elicited by electrical stimulation of left or right vocal cord (train of 5 stimuli, 200 μs duration, ISI 2–4 ms, intensity < 10 mA) and recording from the contralateral side. Reproducible responses were obtained from the contralateral vocal cord at end of surgery. Patient awaked without new neurological deficits, in particular dysphonia, dysphagia or respiration troubles. The preservation of LAR in the removal of IV ventricle tumors in children could correlate with post-operative clinical outcomes.