Bulging of the Oval Window in Common Cavity Deformity: A Possible Predictor of Meningitis.

OBJECTIVE:To investigate the prevalence-rate of oval window bulging in the common cavity and its association with bacterial meningitis. PATIENTS:CT and clinical files of 29 children with preliminary diagnosis of common cavity deformity were collected from 13 Italian centers. INTERVENTION:A retrospective case review study was conducted with a centralized evaluation of the temporal bone CT imaging was performed at Azienda Ospedale - Università Padova, Padova, Italy. MAIN OUTCOME MEASURE:Diagnosis of common cavity was reviewed; in addition, a fluid protrusion into the middle-ear cavity through the oval window at CT imaging was considered as oval window bulging. Its association with the history of bacterial meningitis was investigated. RESULTS:Common cavity deformity was confirmed in 14/29 children (mean-age 11.4 ± 3.8; age-range 5-20; nine females) referred with this diagnosis. In 7/14 patients, the common cavity deformity was bilateral (i.e., 21 common cavities). Oval window bulging was found in 3/19 common cavities (concomitant middle-ear effusive otitis hampered the evaluation in two cases), while the internal acoustic meatus fundus was defective in 10/21 cases. History of bacterial meningitis was found in three children (21%) and two of them had oval window bulging at CT. In the case unrelated to oval window bulging, meningitis occurred late at the age of 12 during acute otitis contralateral to common cavity deformity (ipsilaterally to incomplete partition type 1). CONCLUSION:Patients harboring common cavity deformity have a high risk of meningitis in their first years of life. Oval window bulging seems to be associated with a higher risk of meningitis. This information might be important for appropriate surgical planning.