Recurrent laryngeal nerve (RLN) injury is a serious complication of thyroid surgery. Intraoperative neural monitoring allows functional assessment of the RLN during dissection, but first-side loss of signal (LOS) during planned bilateral thyroidectomy creates a difficult intraoperative dilemma. Misinterpreting false LOS may lead to unnecessary staged procedures, while overlooking true LOS risks bilateral vocal fold paralysis. This structured narrative review, based on a focused PubMed search (2000-2026), addresses the practical management of first-side LOS in three steps. First, when LOS occurs, the surgeon must systematically exclude false causes such as equipment failure, endotracheal tube malposition, and residual neuromuscular blockade before accepting LOS as genuine. Second, once confirmed, the injury mechanism (traction versus structural), signal loss pattern (segmental versus global), and any intraoperative recovery on continuous monitoring help estimate the likelihood of postoperative vocal fold palsy. Third, in benign bilateral disease, current evidence generally supports staged thyroidectomy as the safest default to avoid bilateral RLN dysfunction. Immediate contralateral completion may still be considered in high-priority situations such as invasive thyroid cancer or impending airway compromise, following individualized risk-benefit assessment. First-side LOS should be treated as a structured decision point, and standardized troubleshooting combined with careful interpretation of monitoring data can support safer and more transparent surgical judgment.
Sang Joon Lee (Fri,) studied this question.