1. Preoperative evaluation of thyroid cancer patients should be routinely evaluated for bilateral vocal fold activity before surgery. Laryngoscopy (indirect laryngoscopy or fiberoptic laryngoscopy) can be performed. If there are signs of reduced or even fixed vocal fold activity, tumor compression or invasion of the recurrent laryngeal nerve should be highly suspected, which helps to assess the condition and surgical risk. In addition, for patients with clinical or imaging examinations (e.g. neck CT) suspecting tumor adjacent to or invading trachea, preoperative fiberoptic bronchoscopy should be performed to assess whether the tumor invades the whole layer of trachea to the tracheal lumen, as well as the size of invasion and whether it affects anesthesia tracheal intubation, etc., according to which the corresponding surgical plan and anesthesia plan can be formulated.
2. Postoperative evaluation
If the tumor is found to invade the recurrent laryngeal nerve during surgery, or if the laryngeal nerve monitoring indicates that the function of the recurrent laryngeal nerve is affected, the recovery of vocal cord movement can be assessed through laryngoscopy after surgery. In patients who have undergone tracheostomy or tracheotomy due to bilateral invasion of the recurrent laryngeal nerve, laryngoscopic assessment of vocal cord movement can be performed to decide the timing of removing the tracheal tube or performing tracheostomy repair.