A few patients find that their tone becomes lower after thyroid cancer surgery, which may be related to damage to the superior laryngeal nerve.
The superior laryngeal nerve (SLN) is in close proximity to the superior pole of the thyroid gland. It is easily injured during surgical ligation of the superior thyroid pole vessels. The incidence of injury to the superior laryngeal nerve has been reported to be 5% to 28%.
The supraglottic nerve is divided into sensory and motor branches. The former governs sensation in the larynx, and after injury, choking and coughing can occur as food enters the airway, more pronounced when eating liquid food; the latter can tighten the vocal cords, and after injury, the vocal cords are relaxed, unable to produce high notes, and the pitch becomes lower, but the voice is not hoarse.
Choking symptoms can disappear after a few weeks in most patients with damage to the superior laryngeal nerve, but the lowered pitch is difficult to completely improve.
Co-written by Dr. Jiaqian Hu, Cancer Hospital of Fudan University