Unilateral recurrent nerve
paralysis leads to glottic insufficiency, causing a significant lack of vocal ability. In contrast, bilateral
palsies present with
stridor on inspiration due to glottic
stenosis. Most of the underlying lesions are iatrogenic, with thyroid surgery being the single most important causative factor. However, a variety of different reasons can lead to such a condition. Whenever aetiology is uncertain a complete diagnostic work-up is mandatory. Indirect laryngoscopy confirms the diagnosis. Laryngeal electromyography is of great value because it differentiates between
paralysis and
ankylosis of the cricoarytaenoid joint. Moreover, in many cases laryngeal electromyography provides a reliable prognosis of clinical outcome. While unfavorable results can be predicted with high accuracy, correct prognosis of complete recovery is more difficult.
Speech therapy is the treatment of choice in case of unilateral recurrent nerve
palsy. Only if a significant glottal gap persists medialization procedures may become useful for voice improvement. Endoscopic as well as open approaches are available for this purpose. Bilateral recurrent nerve
palsies need to be addressed surgically in the vast majority of cases. Today, a variety of endoscopic techniques for widening the glottic airway are available. Compared to permanent
tracheostomy these procedures have much less impact on the patient's quality of life and should be preferred whenever possible. Inevitably, voice quality is traded for airway normalisation. However, modern surgical techniques accomplish very tolerable phonatory results.