Impaired movement of the cricoarytenoid joint (CAJ) is thought to be responsible for postintubation hoarseness and immobility of the vocal ligament. In an attempt to simulate the laryngeal complications associated with endotracheal intubation, Paulsen et al. intubated and extubated 37 unfixed larynges obtained from cadavers of people aged 25–89 within 48 h of death. The group specifically attempted to simulate the force of an endotracheal tube impinging on the arytenoid cartilage during intubation to reproduce the clinical result of arytenoid subluxation.
The research group conducted a series of intubation trials in the hand-held larynges. The first injury mechanism was tested in nine right arytenoids and nine left arytenoids by first introducing the endotracheal tube under view into the larynx until the tip of the left or right arytenoid was inside the lumen of the tube. The tube was then inserted with a jerky motion. A second injury mechanism was tested in another nine larynges by introducing the tube into the larynx under view until the cuff had passed the subglottic region. The cuff was filled with air, and the tube was then pulled back through the cords with a jerky motion. In the final nine larynges, the researchers manually attempted to subluxate the arytenoid joint by squeezing the CAJ and applying pressure in the anterior–inferior direction (right CAJ) and in the posterior–lateral direction (left CAJ).
Interestingly, none of the attempts using intubation or manual squeezing was successful in producing persistent subluxation of the arytenoid cartilage. Histologic analysis did show injuries in the synovial folds of some CAJs as a result of intubation attempts. Several CAJs showed chondrocyte clusters near the joint surface or a roughening of the entire cartilaginous joint surface. In a healthy state, the strong posterior cricoarytenoid ligament prevents dislocation of the arytenoid cartilage. Therefore, intubation trauma is unlikely a result of subluxation per se , but is more likely a consequence of the formation of a hemarthros or fractures of the joint bodies, leading to fixation of the joint surfaces in an abnormal position.