Partial intraoperative signal recovery is associated with normal postoperative vocal cord motility in patients with intraoperative loss of signal

Loss of signal (LOS) at intraoperative nerve monitoring (IONM) is defined as an >100 mV amplitude decrease and a >10% latency reduction and represents a predictor of postoperative impaired vocal cord motility (VCM). We aimed to evaluate if an intraoperative signal recovery (ISR) after LOS may predict a positive outcome of VCM. Among 5884 consecutive intermittent IONM-guided thyroidectomies (April 2021- March 2025) all the patients in whom a LOS was observed were evaluated. Topic and intravenous corticosteroids were administered to all of them. Eventual recovery was evaluated after 20 minutes. Patients with an ISR less than 50% compared to the baseline were included. The rate of vagal signal (VS) ISR was defined as a percent from the minimum value: VS-recovery–VS-minimal/VS-predissection–VS-minumum. ISR was correlated to VCM (ROC curve analysis). Among 169 patients with LOS, 65 (38.5%) showed ISR, with 48 (73.8%) of them exhibiting normal VCM on postoperative day 1 (POD-1). The remaining 17 patients with impaired VCM on POD-1 recovered normal VCM on POD-15 (7–10.8%) or POD-30 (10–15.4%). The AUC for impaired VCM at POD-1 was 0.938 (95% CI: 0.849–0.983, p <0.0001) and the ISR cut-off was 13%, with a 94.1% sensitivity and a 89.6% specificity. All patients with ISR >31% showed normal VCM. All patients with ISR <13% exhibited impaired motility at POD-15 but recovered at POD-30. ISR can predict full recovery of VCM. ISR >31% is associated with normal postoperative VCM and staged thyroidectomy could be avoided in this subgroup of patients with LOS.