Endotracheal Tube Versus Transcartilage Needle Electrodes for Nerve Monitoring in Thyroid Surgery

Intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve during thyroidectomy is most commonly performed with surface electrodes embedded in the endotracheal tube (ETT). ETT electrodes are prone to malposition, rotation and secretions, which can produce low signal amplitudes and false signal loss. Transcartilage needle electrodes (TCN), placed into the thyroid cartilage, have been reported to yield higher and more stable amplitudes. This single-centre prospective study records ETT and TCN signals simultaneously in the same patient during thyroidectomy, so that each patient serves as their own control. The primary aim is to compare how often each electrode type shows a false amplitude decrease of more than 50% in nerves without true injury. Voice and swallowing outcomes are assessed before surgery and at 2 weeks and 3 months after surgery using the Turkish versions of the Voice Handicap Index-10 and the Eating Assessment Tool-10.

Inclusion Criteria: * Age 18 years or older * Scheduled for primary total thyroidectomy or hemithyroidectomy * Normal vocal cord mobility on preoperative laryngoscopic examination * Able to read and complete the VHI-10 and EAT-10 questionnaires * Written informed consent Exclusion Criteria: * Preoperative vocal cord paralysis or paresis * Previous thyroid, parathyroid or neck surgery, including completion thyroidectomy * Previous radiotherapy to the neck * Advanced thyroid cancer with invasion of the trachea, oesophagus or larynx * Anatomy preventing needle electrode placement, including severely calcified thyroid cartilage, previous laryngeal trauma or previous laryngeal surgery * Neuromuscular disease such as myasthenia gravis, or other neurological disease affecting nerve conduction * ASA physical status 4 or higher * Planned transoral or endoscopic approach * Pregnancy * Bleeding diathesis, or anticoagulant treatment that cannot be interrupted before surgery * Concurrent neck dissection planned with thyroidectomy * Expected inability to comply with the follow-up protocol