A prospective evaluation of recurrent laryngeal nerve paralysis during thyroidectomy

Hypothesis: Recurrent laryngeal nerve paralysis after thyroidectomy can be unrecognized without routine laryngoscopy, and patients have a good potenti al for recovery during follow-up. Design: A prospective evaluation of vocal ford function before and after th yroidectomy. Periodic vocal cord assessment was performed until recovery of cord function. Persistent cord palsy for longer than 12 months after the o peration was regarded as permanent. Setting: A university hospital with about 150 thyroid operations performed by I surgical team per year. Patients: From January 1, 1995, to April 30, 1998, 500 consecutive patients (84 males and 416 females) with documented normal cord function at the ips ilateral side of the thyroidectomy were studied. Main Outcome Measures: Vocal cord paralysis after thyroidectomy. Results: There were 213 unilateral and 287 bilateral procedures, with 787 n erves at risk of injury. Thirty-three patients (6.6%) developed postoperati ve unilateral cord paralysis, and 5 (1.0%) had recognizable nerve damage du ring the operations. Complete recovery of vocal cord function was documente d in 26 (93%) of 28 patients. The incidence of temporary and permanent cord palsy was 5.2% and 1.4% (3.3% and 0.9% of nerves-at risk), respectively. A mong factors analyzed, surgery for malignant neoplasm and recurrent subster nal goiter was associated with an increased risk of permanent nerve palsy. Primary operations for benign goiter were associated with a 5.3% and 0.3% i ncidence (3.4% and 0.2% of nerves at risk) of transient and permanent nerve palsy, respectively. Conclusion: Unrecognized recurrent laryngeal nerve palsy occurred after thy roidectomy. Thyroid surgery for malignant neoplasms and recurrent substerna l goiter was associated with an increased risk of permanent recurrent nerve damage. Postoperative vocal cord dysfunction recovered in most patients wi thout documented nerve damage.