Authors: Kerstin Lorenz Mohammed Abuazab Carsten Sekulla Rick Schneider Phuong Nguyen Thanh Henning Dralle
Publish Date: 2013/12/18
Volume: 38, Issue: 3, Pages: 582-591
Abstract
Systematic studies of intermittent intraoperative neuromonitoring IONM have shown that IONM enhances recurrent laryngeal nerve RLN identification via functional assessment but does not significantly reduce rates of vocal cord VC paralysis VCP The reliability of functional nerve assessment depends on the preoperative integrity of VC mobility The present study was therefore performed to analyze the validity of IONM in patients with preexisting VC paralysisOf 8128 patients 285 35 with preoperative VCP underwent thyroid surgery using standardized IONM of the RLN and vagus nerves VNs VC function was assessed by pre and postoperative direct videolaryngoscopy Quantitative parameters of IONM in patients with VCP were compared with IONM in patients with intact VC function Clinical symptoms and surgical outcomes of patients with preexisting VCP were analyzedA total of 244 patients revealed negative and 41 revealed positive IONM on the side of the VCP VCP with positive IONM revealed significantly lower amplitudes of VN and RLN than intact VN p = 0010 and RLN p = 0011 Symptoms of patients with VCP included hoarseness 25 dyspnea 29 stridor 13 and dysphagia 13 13 were asymptomatic New VCP occurred in five patients ten needed tracheostomy for various reasons and one patient diedPatients with preexisting VCP revealed significantly reduced amplitude of ipsilateral VN and RLN indicating retained nerve conductivity despite VC immobility Preoperative laryngoscopy is therefore indispensable for reliable IONM and risk assessment even in patients without voice abnormalities
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