Triple-Layer Transmastoid Repair of a Posterior Fossa Plate Defect in Cholesteatoma Presenting with Recurrent Otogenic Meningitis.

Background: Cholesteatoma-related posterior mastoid plate defects may provide a route for recurrent otogenic meningitis. Case Presentation: A 32-year-old man with chronic right otorrhea and two prior bacterial meningitis episodes had HRCT evidence of mastoid cholesteatoma and a focal posterior mastoid plate defect with dural exposure. A retroauricular canal-wall-up mastoidectomy was performed; matrix was dissected from intact posterior-fossa dura. The defect was repaired using a three-layer onlay construct of temporalis fascia, ipsilateral conchal cartilage, and free temporalis muscle. Histopathology confirmed cholesteatoma. No CSF sample was obtained at assessment because there were no features of active meningitis; historical culture and pathogen data were unavailable. The postoperative course was uncomplicated, with no CSF leak, facial nerve dysfunction, recurrent otorrhea, or meningitic symptoms through 12 months of clinical follow-up. Conclusion: Single-stage transmastoid triple-layer autologous reconstruction may restore separation between the mastoid cavity and posterior cranial fossa in cholesteatoma-associated posterior-fossa mastoid defects.