Objective Assessment of Postoperative Swallowing Difficulty Through Ultrasound in Patients Undergoing Thyroidectomy

Swallowing discomfort is a common postoperative complaint in patients undergoing thyroidectomy. Contraction of the strap muscles might cause resistance to elevation of the laryngotracheal unit, and downward movement of the laryngotracheal unit may lead to swallowing discomfort. However, few studies have evaluated the mechanism related to limited laryngotracheal elevation after thyroidectomy. We aimed to objectively verify the presence of postoperative impaired laryngotracheal elevation through ultrasound evaluation in patients undergoing thyroidectomy and evaluate its relationship with limitation of laryngotracheal elevation. This is a prospective clinical study. Among patients undergoing hemithyroidectomy and total thyroidectomy, the patients who were followed up for ≥ 6 months were selected (N = 40). Ultrasound evaluation was done preoperatively and at 1, 3, and 6 months postoperatively. Laryngotracheal movement was recorded and the length of elevation was measured. Symptom after thyroidectomy was evaluated through swallowing-related items of thyroidectomy-related voice questionnaire. Ultrasound evaluation verified the presence of limited laryngotracheal elevation postoperatively in patients undergoing thyroidectomy. After thyroidectomy, the swallowing-related score was significantly increased, and was recovered time-dependently at 1 month. Laryngotracheal elevation showed significant decrease after thyroidectomy. The symptom score of swallowing was significantly correlated with the length of laryngotracheal elevation. Post-thyroidectomy ultrasound evaluation verified that laryngotracheal elevation was significantly impaired. Presence of adhesion between the laryngotracheal unit and the superficial soft tissue was the probable cause of the limitation at 6 months after thyroidectomy. The length of laryngotracheal elevation was related to the symptom score of swallowing after thyroid surgery.