Recurrent laryngeal nerve damage and phonetic modifications after total thyroidectomy: surgical malpractice only or predictable sequence?

Abstract

Modifications of phonation occurring after total thyroidectomy (TT) are usually attributed to surgical malpractice, but other causes of voice impairment even in nonoperated subjects should also be taken into account. This study analyzes 208 patients who underwent TT from January 1, 1999 through December 31, 2001. Follow-up ended on December 31, 2003. Only cases in which the surgeon ruled out the possibility of operative damage to the laryngeal nerves were included. All patients underwent pre- and postoperative clinical and instrumental nose and throat examination (NTE). Preoperatively, 86 patients (41%) showed hoarseness or dysphagia: 4 (2%) monoplegia and 12 (6%) hypomobility of the vocal cords due to impaired function of the recurrent laryngeal nerve (RLN); 6 (3%) cord hypotonia due to impairment of the superior laryngeal nerve (SLN); 34 (16%) dysphagia: and 30 (14%) hoarseness due to other causes. At follow-up 1 month after surgery, 71 patients (34%) had an onset of previously absent signs and symptoms: 8 (4%) had palsy of one vocal cord (2% permanent); 6 (3%) had cord hypomobility (all temporary); 12 (6%) had cord hypotonia due to disease of the SLN, 4 of which (2%) were permanent; 44 patients (21%) had symptoms due to scarring and adhesions between the laryngotracheal axis and the prethyroid muscles and between these and the skin. One patient (0.5%) had a nodular cord lesion that occurred after 3 months. Overall, more than one-third of the patients had preoperative voice modifications or swallowing impairment, around one-third had these problems after TT, and less than one-third were free of pre- and postoperative complications. The surgeon's care to avoid damage to the anatomica integrity of the of laryngeal nerves does not exclude functional problems of the nerves and of laryngeal dynamics. In fact, such problems could be referred to outcomes linked to the operation itself (hematoma, edema, scarring adhesion) or to events that only temporarily follow surgery but must be considered as an unavoidable sequel (e.g., neuritis, viral neuritis, myopathy). The patient should undergo a careful clinical and instrumental NTE to detect conditions prior to surgery, and the information provided by the surgeons should be thorough to allow the patient to be aware of all possible sequels and consequences.