Influence of Non-Neuronal Factors on Post-Thyroidectomy Dysphonia

Objectives: We present a prospective study assessing the real incidence, aetiology, and evolution of vocal impairment following total thyroidectomy. Patients and method: Sixty-six patients who underwent total thyroidectomy between 2003 and 2006 were included, recording demographic and analytic variables, with emphasis on subjective vocal changes observed after surgery, measured by means of the GRBAS scale. Acontrol group of 25 patients operated under general anaesthesia and oro-tracheal intubation was chosen using random sampling. Results: In 30 patients (45.5%), post-operative dysphonia was observed. Among these, only 2 (3%) were permanent, and 11 were due to nerve damage (10 inferior and 1 superior laryngeal nerves). In 8 patients (12.2%), GRBAS score was above 5. In the rest of these 30 patients, the complaint was a single decreased tone (10 cases), lack of intensity (9 cases) and vocal fatigue (3 cases), always with a GRBAS score equal to or less than 2 points. The most significantly related factor with the onset of dysphonia was the section of strap muscles (OR=12.5). Conclusions: Dysphonia is a common complication of total thyroidectomy, but its incidence is not always related to nerve injury. Some technical (and sometimes avoidable) factors, such as the section of prelaryngeal muscles, could have an important relationship with this adverse event.