Comparison of Intr-operative Neuromonitoring Technique in Trans-oral Endoscopic Thyroidectomy Vestibular Approach

Transoral endoscopic thyroidectomy vestibular approach (TOETVA) has the advantage of scarless cosmesis but has limitations of recurrent laryngeal nerve (RLN) palsy. Intermittent intraoperative neuromonitoring (I-IONM) techniques have been utilized during TOETVA to identify and map RLN to prevent RLN injury. However, the insult may still occur between two neural stimulations. Continuous intraoperative neuromonitoring (C-IONM) has been used in TOETVA to persistent stimulation of RLN. but only in our hospital. This rare use may be related to technical challenges. Recently, we successfully developed a novel technique of percutaneous C-IONM using an external fixator to secure the stimulation probe to steadily monitor the real-time functional status of RLN during the TOETVA. In this retrospective study, 304 patients undergone TOETVA were enrolled and divided according to the usage of IONM techniques into percutaneous or peroral intermittent and continuous groups. Patient's age, sex, BMI, thyroid disease, operation time, EMG signal and RLN palsy rate were compared to verified the feasibility, safety, and effectiveness of different IONM techniques. We hypothesized percutaneous C-IONM has the superiority in early detection of RLN injury and reducing of RLN palsy in TOETVA.