[Thyroid carcinoma and the recurrent nerve. Recurrence fall-out, incidence and causal circumstances in a large case-load of patients with thyroid carcinoma].

Impairment of vocal cord function is a threat to patients with thyroid carcinoma; either due to the tumor having infiltrated the larynx or the recurrent nerve, or to accidental damage to the laryngeal nerves during thyroid surgery. We have reviewed 1,245 patients' records which were filed under the diagnosis of thyroid carcinoma at Det Norske Radiumhospital from 1956 to 1978. Pareses of vocal cords were noted in 465 patients (37.3%) during the course of their illness. In 135 patients (10.8%) the pareses were due to infiltration by the tumor, most commonly seen in anaplastic carcinoma. In 267 patients (21.4%) the pareses followed surgery; planned resections of the recurrent nerves were performed in 48 patients (3.9%). Transient pareses with normal vocal cord movements within months were experienced in 137 cases (11%). Permanent paralysis caused accidentally during surgery was seen in 82 patients, representing 6.6% of all patients and 4.7% of the surgically exposed nerves. We stress the need for pre- and postoperative evaluation of vocal cord movement as an aid to future diagnosis and optimal surgical planning.