Voice and Swallowing Disorders After Thyroid Surgery

The aim of the study was to evaluate voice and swallowing function following thyroid surgery, to identify dynamic changes during the follow-up period of 12-18 month and to find possible indicative signs of permanent or temporary vocal fold palsy.

All participants (N = 110) were prospectively enrolled from the preoperative thyroid surgery patients between September 2013 and December 2016. All subjects underwent preoperatively, first week and 12-18 month postoperatively videolaryngostroboscopy, filled in subjective evaluation of voice (voice handicap index, [VHI]) and swallowing (swallowing impairment score) complaints. Acoustic voice analysis (AVA), maximum phonation time (MPT) measurement and perceptual voice evaluation were conducted. In the presence of laryngeal damage, additional first and sixth-month follow-up visits were planned. Patients, whom we suspected laryngeal nerve damage, underwent laryngeal electromyography 4 weeks after the operation.

On first postoperative week evaluation, no objective voice changes within patients with postoperatively intact laryngeal nerves were found. Subjective evaluations showed decline in VHI physical domain and increased strain in postoperative voice. Patients with postoperative nerve damage had a drastic decline in subjective voice quality (VHI all subscales and total score), AVA parameter jitter, MPT and perceptual voice quality. Subjective evaluation of swallowing revealed disturbances in all patients regardless of the nerve damage. We noticed remarkable differences in first week and first month visits between patients with permanent and temporary palsy in VHI total score and physical domain, MPT and perceptual breathiness and asthenia in voice. Regardless of the nerve injury, by the end of the follow-up period all changes had become statistically insignificant with the exception of perceptual evaluation of voice quality.

Patients with postoperative laryngeal nerve damage experience substantial deterioration of both subjective and objective voice quality with more extensive impairment in patients with permanent paralysis. Thyroid surgery causes subjective swallowing changes irrespective of laryngeal nerve damage. In patients without laryngeal nerve damage, swallowing function improves following thyroidectomy. Possible indicators for permanent paralysis are delayed recovery in the values of MPT and jitter and persistent perceptual breathiness and asthenia.