Factors for Favorable Outcomes After Sialendoscopy for Radioactive Iodine‐Induced Sialadenitis of Parotid Gland: An Exploratory Study Toward a Phenotypic Patterns

BACKGROUND: Radioactive iodine (RAI) therapy can induce radioactive iodine-induced sialadenitis (RAIS). Sialendoscopy is an effective treatment for RAIS, but predictors of favorable outcomes remain poorly defined. This study aimed to identify functional and anatomical factors associated with favorable outcomes following sialendoscopy in RAIS patients. METHODS: We retrospectively reviewed 44 cases who underwent sialendoscopy for RAIS. Favorable outcome was defined as a symptom resolution without the need for additional medication or revision surgery. RESULTS: In the multivariate model, ΔSFR(pre) (difference between stimulated and unstimulated preoperative SFR) (p = 0.035), symptom duration (p = 0.039), and distal stenosis (p = 0.024) were confirmed as predictors. ROC curve analysis determined the optimal cutoffs for the two continuous independent predictors: low ΔSFR(pre) < 0.41, early intervention < 4.5 months. CONCLUSIONS: This study identified low ΔSFR(pre), early intervention, and distal stenosis of Stenson's duct as associated with favorable outcome.