The Diagnosis and Treatment of Arytenoid Dislocation

Abstract

Vocal fold paralysis and arytenoid dislocation are the differential symptoms for unilateral vocal fold movement disorder. However, their diagnosis is difficult. To diagnose dislocation, it is necessary to understand the movements characteristic of unilateral fold paralysis. A particularly important finding of paralysis is the passive gliding movement that is displaced in the cranial direction during phonation. The presence of this movement is diagnostic of paralysis rather than dislocation. A number of previous reports on dislocation have diagnosed the presence of this passive movement as dislocation. In Japan, the term ‘fixation’ is often used to describe the position of the paralyzed vocal folds, as in ‘mid-position fixation’ or ‘sub-median fixation’. There seems to be a misconception that ‘paralyzed vocal cords are immobilized’. In the case of dislocation, by contrast, the muscular process is unable to move beyond the midline of the articular surface, and the movement of the arytenoid is severely restricted and immobile. It has been misunderstood that immobility is paralysis while wobbling is dislocation. However, paralysis is the presence of wobbling movement (passive gliding movement), and dislocation is immobilization and inability to move. Dislocations have previously been divided into two categories of anterior and posterior dislocations, but vertical dislocations have not been mentioned. In past reports, the terms ‘anterior’,‘posterior’,‘medial’, and ‘lateral’ have been used to refer to the position of dislocation. However, these terms do not indicate the position in the vertical direction. We divided the cricoid facet into four areas: mediocaudal, laterocaudal, mediocranial and laterocranial. We published on recurrent adductor branch paralysis in 2010. Gradually, the concept of partial laryngeal palsy has become more widespread. Looking at previous reports, adductor branch paralysis may have been included in many studies diagnosing posterior dislocation (mediocranial). Understanding the characteristics of adductor branch paralysis is crucial. It is important to understand the three-dimensional arrangement of the arytenoid cartilage for the diagnosis of unilateral vocal fold movement disorder and clarifying the characteristics of paralysis.