Middle Cranial Fossa Repair of a Mastoid Tegmen Encephalocele Using a Pedicled Temporalis Muscle Flap: Surgical Video

Introduction: Temporal bone encephaloceles are uncommon lesions resulting from defects of the tegmen tympani or tegmen mastoideum, allowing herniation of intracranial contents into the middle ear or mastoid cavity. Patients may present with disabling otologic symptoms, cerebrospinal fluid leakage, recurrent meningitis, conductive hearing loss, or aural fullness. Surgical repair through the middle cranial fossa approach provides excellent exposure for definitive reconstruction of the skull base defect. We present the surgical technique for repairing a mastoid tegmen encephalocele. Case Report: A 42-year-old man presented with progressive right-sided otologic symptoms, including conductive hearing loss, persistent aural fullness, pulsatile tinnitus, intermittent cerebrospinal fluid otorrhea, and recurrent episodes of middle ear inflammation, significantly impairing his quality of life. High-resolution computed tomography of the temporal bone demonstrated a bony defect involving the right mastoid tegmen with herniation of soft tissue into the middle ear and mastoid cavity. Magnetic resonance imaging confirmed the diagnosis by demonstrating herniation of temporal lobe parenchyma through the tegmen mastoideum defect. The encephalocele exhibited signal intensity identical to normal brain parenchyma on both T1- and T2-weighted sequences, with continuity to the temporal lobe and no evidence of contrast enhancement. A right temporal craniotomy was performed through a middle cranial fossa approach. Following extradural elevation of the temporal lobe (middle fossa peeling), the tegmen defect and herniated encephalocele were identified. The herniated tissue was reduced, and the skull base defect was reconstructed using a multilayer technique consisting of autologous temporalis fascia, fibrin sealant, and a pedicled temporalis muscle flap, achieving a durable separation between the intracranial and temporal bone compartments. Results: The patient experienced an uneventful postoperative recovery, with complete resolution of otologic symptoms and no evidence of cerebrospinal fluid leakage or recurrence during follow-up. Conclusion: The middle cranial fossa approach provides excellent visualization of tegmen defects and allows safe reduction of the encephalocele with durable multilayer skull base reconstruction. The use of autologous temporalis fascia combined with a vascularized pedicled temporalis muscle flap offers a reliable technique for restoring skull base integrity while minimizing the risk of recurrence and cerebrospinal fluid leakage.