Middle ear pressures in patients with nasopharyngeal carcinoma and their clinical significance

Abstract

AbstractThere is a paucity of studies investigating middle ear pressures (MEPs) in patients with nasopharyngeal carcinoma (NPC). This paper prospectively examines MEPs in patients with nasopharyngeal carcinoma before and after radiotherapy and discusses their clinical significance. Newly diagnosed patients with nasopharyngeal carcinoma were studied before and at three to 12 months (mean 7.5 months) after radiotherapy. MEPs were measured by tympanometry. Thirty-three patients completed the study. The mean MEP before and after radiotherapy was −55.2 mm water(range −250 to 45 mm water) and −73.1 mm water (range −215 to 35 mm water) respectively. About two-thirds of assessable ears had an increase in negative MEPs after irradiation and the rest had less negative MEPs after irradiation. Those ears which developed post-irradiation middle ear effusions were found to have pre-irradiation negative middle ear pressures of at least −45 mm water. These findings provide possible explanations for some unexplained audiometric observations previously made in patients with nasopharyngeal carcinoma after radiotherapy. Tympanometry before radiotherapy may prove to be useful in identifying ears with a high risk of developing post-irradiation middle ear effusion.