Office-based laryngoscopic observations of recurrent laryngeal nerve paresis and paralysis

To evaluate the endoscopic criteria of recurrent laryngeal nerve disorders, we performed a retrospective evaluation of videolaryngoscopic recordings from 50 patients with recurrent laryngeal nerve disorders.

The videolaryngoscopic examination was performed with rigid and flexible endoscopes. The range of motion of three laryngeal structures was assessed: the vocal ligament, the vocal process, and the arytenoid "hump" (mainly the corniculate region).

Comparison of movement of these three structures revealed discrepancies. In 16 of 45 patients (36%) rigid endoscopy showed movements of the arytenoid hump associated with absence of any mobility of the vocal process and vocal ligament. In 5 patients the extent of movement of the vocal process and vocal ligament was less than that of the arytenoid hump. Only in 24 of 45 cases were the ratings for the vocal process, vocal ligament, and arytenoid hump identical. The findings of fiberscopy were comparable.

In assessing recurrent laryngeal nerve disorders via laryngoscopy, sole judgment of the arytenoid hump movement can mislead. Our interpretation suggests that visible movement of the mucosa covering the arytenoid and accessory cartilages is not always paralleled by movement of the arytenoid cartilage itself. It was shown that the best criterion to rely on in endoscopy is movement of the vocal process or the vocal ligament.