Objectives: A transoral approach to laser myoneurectomy of the thyroarytenoid muscles was recently reported as an effective technique for treatment of adductor spasmodic dysphonia (ASD). The short-term results were encouraging. In this study, a long-term surgical outcome of this technique is investigated.
Study design: A prospective clinical series.
Methods: Fifty-two patients with ASD underwent transoral laryngomicrosurgery with a CO(2) laser to resect the ventricular folds followed by myoneurectomy of the thyroarytenoid muscles. The nerve fibers of recurrent laryngeal nerve terminating at the thyroarytenoid muscle, which were frequently found branching deeply among the posterior belly of this muscle, were vaporized. Care was taken not to damage the vocal ligaments, lateral cricoarytenoid muscles, or arytenoid cartilages. Pre- and postoperative subjective voice assessments, and acoustic and aerodynamic measurements, were performed and statistically analyzed.
Results: Twenty-nine of the 52 patients who were followed up for more than 12 months (range, 12-63 months; mean, 31 months) were studied. Moderate and marked vocal improvement was achieved in 90% (26/29) of the patients. Three patients had 30% improvement, which was reported as unsuccessful. Eight of the 26 patients who were satisfied with their postoperative voice still had a mild strain during phonation. Of the eight patients, seven achieved normal or nearly normal voice quality after revision laser surgery. No significant vocal deficit or paralysis was observed in any patient.
Conclusions: After long-term follow-up of 31 months on average, approximately 90% of the ASD patients obtained moderate to marked improvement of vocal performance after transoral laser surgery. The long-lasting outcome is encouraging.