[Bilateral recurrent laryngeal nerve paralysis]

Abstract

This paper seeks to provide the reader with a state-of-the-art review of the aetiology, diagnosis and clinical management of bilateral recurrent nerve paralysis. The recurrent laryngeal nerves are more frequently involved in bilateral paralysis than any other cranial nerve. 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 the aetiology is uncertain, a complete diagnostic work-up is mandatory. Massive stridor on inspiration is the key symptom. Indirect laryngoscopy confirms the diagnosis. Laryngeal electromyography is of great value because it differentiates between paralysis and ankylosis of the cricoarytenoid joint. Moreover, in many cases, laryngeal electromyography yields reliable prognosis of clinical outcome. While unfavorable results can be predicted with high accuracy, correct prognosis of complete recovery is more difficult. Clinical management is surgical in the vast majority of cases. A variety of endoscopic techniques for widening the glottic airway are available today and are discussed in detail. Compared to permanent tracheostomy, these procedures have much less impact on the patient's quality of life and should be preferred whenever possible. Since such an operation is irreversible, a decision should be made only in the presence of a reliable electrophysiological prognosis and/or after 6-9 months of watchful waiting. Inevitably, voice quality is traded for airway normalisation. However, modern surgical techniques accomplish very tolerable phonatory results. Timing, type and extent of surgery need to be customised for every patient individually.