Evaluation of chronological changes in videofluorographic findings after transoral videolaryngoscopic surgery to reveal mechanism of dysphagia

Objectives: Transoral surgery preserves good swallowing function in most cases, however, post-operative dysphagia sometimes leads to fatal complication such as aspiration pneumonia. We investigated the chronological changes in swallowing function have not been revealed relation-ship with dysphagia. The primary aim of this study was to reveal the mechanism of dysphagia following transoral surgery by analyzing chronological videofluorography (VF) findings. More-over, the secondary aim of this study was to evaluate the relationship between mechanism of dysphagia and risk factors of patients to clarify the risk for dysphagia lead to prevention of postoperative complications.Methods: 22 patients who underwent transoral videolaryngoscopic surgery (TOVS) for either supraglottic or hypopharyngeal cancer were evaluated swallowing function. We performed VF during the preoperative, postoperative acute, and stable phases and investigated the chronological changes in the VF findings. The following parameters were evaluated by VF: horizontal distance of laryngeal movement, vertical distance of laryngeal elevation, laryngeal elevation delay time (LEDT), Bolus Residue Scale (BRS) scores, and Penetration Aspiration Scale (PAS) scores. Additionally, we evaluated risk factors for postoperative aspiration by investigating relationships between preoperative VF parameters, age of patients, history of radiation therapy, resection area, tumor (T) stage, postoperative Numeric Rating Scale (NRS), and PAS and BRS scores. Results: The median time at which oral feeding was resumed in this study was 9 (2-200) days. The patients who had postoperative acute PAS scores of 4 and above exhibited delays in resuming oral ingestion after surgery. TOVS did not impair laryngeal elevation and LEDT; however, the BRS and PAS scores temporarily worsened in the acute phase compared to the preoperative scores. These scores almost recovered to their preoperative states in the stable phase, and both the BRS and PAS scores worsened and recovered concurrently. Patients who exhibited poor vertical distance in laryngeal elevation as observed via preoperative VF or who had histories of radiation therapy had worse PAS scores in postoperative acute phase VF. Patients with broad resection areas had worse BRS scores in postoperative acute phase VF.