No morphometric abnormality recurrent laryngeal nerve in spastic dysphonia

Spastic dysphonia is a disorder of phonation that is usually markedly improved by surgical resection of one recurrent laryngeal nerve (RLN). In this study, biopsies of the RLN were obtained at surgery from nine patients with spastic dysphonia (disease group) and eight patients with laryngeal cancer (control group). The RLN was found to be composed of several nerve regions having characteristic fiber compositions. For the various nerve regions and for the whole nerve, we evaluated morphology, median fiber diameter, density, and size distribution of fibers. The morphologies of teased fibers were also evaluated. We found no significant differences between the nerves of the disease and control groups. Therefore, we were unable to verify previous reports of neuropathic abnormality of the RLN in spastic dysphonia.