Videolaryngostroboscopic observation of mucus layer during vocal cord vibration in patients with vocal nodules before and after surgery

Abstract

ObjectiveUnder normal conditions, the vocal fold mucus layer is too thin to permit observation using videolaryngostroboscopy (VLS) during phonation. However, vocal nodules (VNs) typically cause congealed and sticky mucus to appear on the vocal fold. Reports in the literature regarding this phenomenon are limited. The aim of this study was to review VLS recordings of VN patients, analyzing changes that occurred in the mucus layer that covers the vocal fold during vibration following VN surgery.Material and MethodsUsing VLS, we studied the occurrence of, and changes in, vocal fold mucus layers in 160 VN patients before and after surgery.ResultsEighty-eight patients (55%) were found to have a mucus layer during preoperative examinations. Of these mucus layers, 21 (13%) were located on the anterior commissure or anterior third of the vocal fold (A), 58 (36.3%) on the junction of the anterior and middle thirds (M), 1 (0.6%) on the posterior third (P), 5 (3.1%) on both A and M and 3 (1.9%) on both M and P. Fifty-six (35%) cases were found to have a mucus layer during postoperative examinations. Of these, 44 (27.5%) were located on A, 8 (5%) on M, 1 (0.6%) on P and 3 (1.9%) on both A and M. These results indicate that changes in the mechanical force on the vocal fold, alteration of the laryngeal secretory gland and improper aerodynamic airflow result in increased mucus viscosity and aggregation in VN patients and that the combination of these factors further increases the severity of dysphonia.ConclusionsSurgery to remove vocal nodes may be an effective method to eliminate both vocal bumps and aggregated mucus. Based on the present results, it is recommended that future research should compare surgery to remove VN against other mucus layer reduction methods in order to determine which is the most effective.