Challenges for Cochlear Implantation Following Lateral Skull Base Encephalocele Repair: Case Studies

Objective: The goals of this study are to report the clinical presentation, radiographic findings, operative strategy, and outcomes in two patients (three ears) who underwent cochlear implantation post temporal bone encephalocele repair and to identify surgical challenges and report strategies associated with the final outcome.

Patients: Two patients (one patient with bilateral encephaloceles and second patient with unilateral encephalocele) underwent a middle fossa craniotomy and a combined mastoid-middle cranial fossa repair of encephalocele respectively at 2 tertiary academic referral centers. The first patient underwent bilateral cochlear implantation while the second patient underwent unilateral cochlear implantation on the side with encephalocele repair.

Results: The initial presenting symptom in both patients was bilateral severe to profound hearing loss. In one case the hearing loss was a result of an explosion while in the other case, it followed chronic ear disease without prior surgeries. Both patients did not report a history of intracranial infections or seizures. One patient (JD) underwent a middle fossa craniotomy for encephalocele repair, while the other patient (JW) underwent a combined postaural mastoid-middle fossa repair. Four months after successful encephalocele repair, both patients underwent cochlear implantation with Cochlear 522 electrodes via a round window approach. The patient with bilateral encephaloceles underwent second side cochlear implant surgery later that same year. There were no intraoperative or postoperative complications. Activation of cochlear implants in both patients was done 6 weeks after cochlear implant surgery and was uneventful.

Conclusion: Cochlear implantation post encephalocele repair can be challenging due to the increased risk of bleeding due to scarring from previous surgery, alteration in anatomical landmarks, contracted mastoid cavity following the dural repair and the presence of titanium mesh at the craniotomy site. Advance planning for management of these patients and intraoperative strategies can help overcome the surgical challenges and improve outcomes. This is the first such report of successful cochlear implantation in patients post encephalocele repair.

No conflict of interest has been declared by the author(s).