Arytenoid Subluxation

Excerpt

Arytenoid subluxation is partial displacement of the arytenoid cartilage within the cricoarytenoid joint. It is a rare complication that typically occurs after a traumatic injury to the cricoarytenoid junction during laryngoscopy and intubation, upper airway instrumentation, and external laryngeal trauma. The arytenoids are a pair of small pyramid-shaped cartilages which articulate with the cricoid cartilage at the cricoarytenoid joint. Both the arytenoids and cricoarytenoid joints are relatively fragile and very vulnerable to injury during laryngoscopy and intubation. Clinicians commonly visualize the bulge in the mucosal surface overlying the arytenoids during laryngoscopy. [Figure 1]

The arytenoids are composed of an apex, a base, and two processes (vocal and muscular). The vocal processes extend anteriorly and provide attachment to the vocal ligament, and are responsible for tension, relaxation, or approximation of vocal folds, while the muscular processes extend posterolaterally and provide a point of insertion for the lateral and posterior cricoarytenoid muscles. These muscles are responsible for opening and closing the glottis by creating lateral and medial movements of the attached vocal cords. The apex articulates with the aryepiglottic fold and corniculate cartilages, and the base articulates with the cricoid cartilage through several ligaments that form the capsule of the synovial cricoarytenoid joint. The cricoarytenoid joint controls the abduction and adduction of the true vocal cords, allowing respiration, phonation, and airway protection.

One often sees the terms subluxation and dislocation used interchangeably. However, a dislocation refers to a complete separation of the arytenoid cartilage from the joint space, whereas a subluxation is partial displacement of the arytenoid within the joint. Both can be considered the same disease with varying degrees of severity, sharing the same pathophysiology. A subluxation can be classified as anterior when the displacement is anteromedial or posterior when the displacement is posterolateral.