Distribution of Bacteria in OME After Radiotherapy For NPC.

Inclusion Criteria: * patients clinical diagnosis of OME or OME after radiotherapy for NPC (Diagnostic criteria: fluid visible in the middle ear and a type B tympanogram). * patients volunteered to participate in the study and signed the informed consent Exclusion Criteria: * NPC recurrence or other malignant tumor after radiotherapy. * clear diagnosis of Eustachian ostium atresia or nasal obstruction diseases, such as severe deviated nasal septum, choanal atresia, osteoradionecrosis of skull base after radiotherapy, etc. * pregnant and lactating women. * patients with severe underlying diseases or with severe liver and kidney dysfunction. * patients who could not cooperate (including poor hearing and radiation encephalopathy) * patients with other middle ear diseases, such as middle ear cholesteatoma, osteoradionecrosis of temporal bone after radiotherapy, etc. * severe deglutition disorders * cleft palate