The Effectiveness of Botulinum Toxin Injection for Cricopharyngeal Dysfunction-Related Dysphagia in Nasopharyngeal Carcinoma Patients

To evaluate the effectiveness of botulinum toxin injection in improving swallowing function in patients with cricopharyngeal muscle dysfunction (CPMD) following radiotherapy for nasopharyngeal carcinoma (NPC). Cohort study. Outpatients with NPC-related CPMD receiving endoscopy-guided botulinum toxin injection at National Cheng Kung University Hospital between 2017–2024. 15 NPC patients with CPMD were enrolled. Swallowing function was assessed using the functional oral intake scale (FOIS), penetration-aspiration scale (PAS), bolus residue scale (BRS), dynamic imaging grade of swallowing toxicity (DIGEST), normalized residue ratio scale for vallecular (NRRS_V) and pyriform sinus (NRRS_P), laryngeal elevation, epiglottic retroflexion, pharyngeal contraction ratio(PCR), bolus clearance ratio (BCR), and temporal swallowing parameters (oral transit time [OTT], pharyngeal response time [PRT], pharyngeal delay time [PDT], pharyngeal transit time [PTT], laryngeal elevation delay time [LEDT]). The Wilcoxon signed-rank test was used to compare pre- and post-injection data. FOIS significantly improved after botulinum toxin injection (p = 0.0002). Objective measures showed a significant reduction in NRRS_P (p = 0.0067). Temporal characteristics also demonstrated significant improvement in OTT, PRT, and PTT (p = 0.0156, p = 0.0303, p = 0.0284, respectively). However, other objective measures showed no significant changes. Botulinum toxin injection may benefit specific swallowing parameters, such as NRRS_P, OTT, PTT, and PRT, and enhance FOIS in NPC patients with radiation-induced CPMD. However, its overall impact on swallowing function remains uncertain.