Cochlear ossification in patients with profound hearing loss following bacterial meningitis.

CONCLUSION

Cochlear ossification following bacterial meningitis is related to causative pathogen, but not age at disease or time point of evaluation. However, progression may occur over time, especially in case of primary signs of ossification.

OBJECTIVE

To investigate the occurrence and degree of cochlear ossification on CT and MRI in patients with bilateral profound hearing loss following bacterial meningitis, in relation to causative pathogen, age at disease, and time point of evaluation. Progression of ossification in cases that underwent more than one scan was evaluated.

METHODS

In the period 1982-2008, 47 cochlear implantations were performed in 34 consecutive candidates suffering from bilateral profound hearing loss following bacterial meningitis. A retrospective review of patient files and preoperative CT and MR images was performed.

RESULTS

Cochlear ossification was observed in 35% of patients and 26% of ears on CT. The corresponding values for MRI were 44 and 30% (difference not significant). Streptococcus pneumoniae infection caused ossification more frequently than Neisseria meningitidis. No difference was found between pediatric and adult cases, and the occurrence of ossification was not related to the time point of evaluation. Signs of progressive ossification were found in cases with two CT scans, especially if ossification was present at the first scan.