Management of Massive Iatrogenic Temporal Lobe Meningoencephalocele and Bacterial Meningitis Following Pediatric Cochlear Implant Surgery.

Objective: To review the management of meningitis, large lateral skull base defect, and meningoencephalocele following pediatric cochlear implant (CI) surgery.

Study design: Case report.

Methods: Patient demographics, medical and surgical history, computed tomography (CT).

Results: An 8-year-old male with congenital severe to profound sensorineural hearing loss underwent uncomplicated right CI surgery at 18 months of age. He returned to his home country and received a bilateral sequential left ear CI at age 2. Five years following his second CI surgery, he presented to his local emergency room with worsening fever, headache, back pain, and vomiting. Lumbar puncture confirmed bacterial meningitis, and he was managed with intravenous antibiotics. The hospital course was complicated by a right-sided facial nerve paresis, prompting a temporal bone CT. Imaging demonstrated a tegmen defect measuring 15 mm × 10 mm with soft tissue opacification involving the entire mastoid and CI harness. He was then referred by family back to our institution. Intraoperatively, we identified a massive temporal lobe meningoencephalocele involving the entire mastoid cavity and engulfing the entire proximal electrode harness. Following middle cranial fossa craniotomy and revision mastoidectomy, proximal and distal array were separated, encephalocele transected, and remaining temporal lobe reduced. The lateral skull base was reconstructed with calvarial bone, temporalis fascia, and bovine collagen graft. The remnant electrode array was removed, a new CI receiver stimulator was fixed postero-superiorly to the cranial defect, and a new multichannel array inserted. A titanium cranioplasty completed the repair. A lumbar drain was placed for 3 days. Recovery and CI activation occurred uneventfully.

Conclusion: Risk of encephalocele and meningitis underscores the importance of early identification, adequate repair, and long-term radiologic follow-up of iatrogenic tegmen defects during pediatric CI surgery.