How is recurrent laryngeal nerve (RLN), injury following thyroid surgery diagnosed?

Updated: Feb 27, 2020
  • Author: Pramod K Sharma, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Techniques for assessing vocal fold mobility include indirect and fiberoptic laryngoscopy. Documentation of vocal fold mobility should be a routine part of the preoperative physical examination of any patient presenting with a thyroid mass. Postoperative visualization should also be performed, as these patients may be asymptomatic, especially at first.

Laryngeal electromyography (EMG) may be useful to distinguish vocal fold paralysis from injury to the cricoarytenoid joint secondary to intubation. Furthermore, EMG may yield information concerning the prognosis of the patient with RLN injury.

Parnes et al (1985) performed laryngeal EMG in 24 patients with vocal fold paralysis due to numerous etiologies (eg, idiopathic causes, surgery, tumor, trauma, neurologic diseases). [9] No patient in whom EMG revealed an absence of motor unit potentials or fibrillation potentials regained movement of the true vocal fold. Of 14 patients who had normal or polyphasic action potentials, 11 regained function. However, most of the tests were performed more than 6 months after the onset of paralysis; therefore, this study revealed little regarding the usefulness of early EMG testing.

The patient with bilateral paralysis of the true vocal folds who presents with airway obstruction after extubation likely requires emergency reintubation or tracheotomy. Fiberoptic laryngoscopy may be performed to confirm the diagnosis if the patient is clinically stable.

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