Vocal and Swallowing Dysfunction Following Thyroid Surgery

Voice changes due to laryngeal dysfunction after thyroid surgery are very common complication. However, very few data in the literatures are available which highlights the impact of thyroidectomy and effects of factors, such as patient age, sex, operation type, surgeons experience, laryngeal nerve injury and orotracheal intubation on voice of patients undergoing thyroid surgery. Prabhat AK et al. 2018 reported that, In majority of cases voice changes are transient. The voice recovery time ranges from less than one-month up to 6 months in majority of cases. Transient voice changes, such as voice fatique, and voice weakness or dysphonia are more common and can happen in most of the cases. The transient voice changes usually occurs because one or more of the nerves are irritated either by moving them out of the way during the dissection of thyroid gland or because of the inflammation or oedema that happens after the thyroid surgery.

One of the indices of success in thyroid surgery is the frequency of complications. The most frequent postoperative complications following thyroidectomy are hypocalcemia and airway complications. These are life threatening and have a significant impact on quality of life . Airway complications may result from postoperative haematoma, vocal cord paralysis, laryngeal oedema, and tracheomalacia .

Recurrent laryngeal nerve palsy (RLNP) is a rare but potentially catastrophic complication of thyroid surgery. Damage to a recurrent laryngeal nerve (RLN) with resultant paralysis of the sole abducting muscle (posterior cricoarytenoid) of the vocal folds can cause symptoms ranging from hoarseness in unilateral lesions to stridor and acute airway obstruction in bilateral damage. RLNP following thyroid surgery is one of the leading reasons for medico-legal litigation against surgeons .

Injury of the laryngeal nerves may not be the only cause of voice changes. Other possible causes include injury of the prethyroid strap muscles and cricothyroid muscles or impairment of laryngotracheal movement due to wound contracture after surgical trauma of the soft tissues. A delicate surgical technique may prevent such complications, but it remains to be clarified whether voice alterations may occur after thyroidectomy without any laryngeal nerve injury. Computerized acoustic analysis of the patients undergoing thyroidectomy without laryngeal nerve injury may help determine possible voice changes objectively .

Dysphagia is a typical symptom experinced preoperatively by patients with enlarged thyroid due to a direct compression of the swallowing organs. In these patients, uncomplicated thyroidectomy often leads to improvements in perceptions of swallowing function. However impaired swallowing and neck strangling frequently occur postoperatively. Intraoperative nerve injury regularly causes postoperative dysphagia, but dysphagia is also complained of after uncomplicated thyroidectomies. These symptoms are usually dismissed by the clinicians or attributed to orotracheal intubation. In many patients, correlations for these swallowing disorders cannot be found in objective test results. Reasons for dysphagia and esophageal motility changes after uncomplicated thyroidectomy could be injury of the perithyroidal neural plexus, changes in the laryngeal vascular supply, postoperative adhesions, decreased pressure of the upper esophageal sphincter, or changed position after thyroidectomy .