Combined Transmastoid and Middle Fossa Approach for Meningoencephalocele Repair: Surgical Video.

Introduction: Temporal bone meningoencephaloceles are uncommon skull base lesions characterized by herniation of the meninges and temporal lobe through defects of the tegmen tympani or tegmen mastoideum. Patients frequently present with disabling otologic symptoms, cerebrospinal fluid (CSF) leakage, conductive hearing loss, recurrent otitis media, pulsatile tinnitus, aural fullness, and, in some cases, recurrent meningitis. Surgical repair aims to restore the integrity of the lateral skull base while preserving hearing and preventing intracranial complications. We present the microsurgical technique of a combined transmastoid and middle cranial fossa approach for the repair of a temporal bone meningoencephalocele. Case Report: A 62-year-old woman presented with progressive right-sided otologic symptoms, including conductive hearing loss, persistent aural fullness, pulsatile tinnitus, intermittent cerebrospinal fluid otorrhea, recurrent middle ear infections, and episodic dizziness. High-resolution computed tomography demonstrated a bony defect involving the right tegmen mastoideum with herniation of intracranial contents into the mastoid cavity and middle ear. Magnetic resonance imaging confirmed a right temporal meningoencephalocele by demonstrating continuity of the herniated temporal lobe with the intracranial compartment. A combined transmastoid and middle cranial fossa approach was selected to achieve complete exposure of both the extracranial and intracranial aspects of the defect. Following mastoidectomy and extradural elevation of the temporal lobe through a temporal craniotomy, the encephalocele was identified, reduced, and the skull base defect was reconstructed using a multilayer technique consisting of autologous temporalis fascia reinforced with a vascularized pedicled temporalis muscle flap. This reconstruction restored the separation between the intracranial and temporal bone compartments while providing a robust vascularized repair. Results: The postoperative course was uneventful. The patient experienced marked improvement of her otologic symptoms, with resolution of CSF leakage and no evidence of recurrence during follow-up. Conclusion: The combined transmastoid and middle cranial fossa approach provides excellent exposure for the management of temporal bone meningoencephaloceles, allowing complete reduction of the herniated tissue and durable multilayer reconstruction of the skull base. The use of a vascularized pedicled temporalis muscle flap combined with autologous fascia represents a reliable technique for achieving long-term repair while minimizing the risk of recurrence and cerebrospinal fluid leakage.