Preventive Effect of Controlled-Release Dexamethasone on Cochlear Ossification in Meningitis Model.

Objective: Despite vaccination and early antibiotic treatment, pneumococcal meningitis remains a disease with significant mortality and morbidity. The resulting inflammatory response can lead to cochlear fibrosis, ossification where cochlear implant surgeries are far challenging. Our study aimed to investigate the preventive effect of controlled-release dexamethasone implant in such cases in terms of structural integrity.

Methods: Twenty-four rats were induced with pneumococcal meningitis and randomized into study (n = 16) and control (n = 8) groups. Controlled-release dexamethasone implants were placed transbullarly into the right round window of the study group. Bilateral cochleas underwent histological examination 3 months post-infection.

Results: In the study, cochlear effects of pneumococcal meningitis were evaluated. The basal turn was significantly more affected by fibrosis and ossification ( = .013 and .010, respectively). Compared with control ears, the dexamethasone implant group showed less fibrosis in all turns and less ossification in the basal turn ( = .014, .003, .044, and .035, respectively).

Conclusion: In pneumococcal meningitis, fibrosis and ossification occur more intensively in the basal turn of the cochlea. Controlled-release dexamethasone implants are effective in preventing cochlear ossification and fibrosis. The prevention from the structural damage indicates the potential role of these dexamethasone implants in post-meningitic hearing loss and easing cochlear implant surgeries.