Managing CSF Leak with Temporalis Muscle Flap for Challenging Skull Base Defect after Radiation Therapy

Introduction: The presence of CSF leak after radiation therapy is very challenging for repair. We reported a case of 56-year-old male with right temporal base osteoradionecrosis and dura radionecrosis presented with CSF leak, 10 months after Boron Neutron Capture Therapy for the treatment of recurrent buccal squamous cell carcinoma, following wide excision and CCRT.

Methods: The CSF leak through the foramen ovale was localized by images. The temporalis muscle flap was harvested according the size of defect measured on the 3D printing skull. A pterional craniotomy was performed to resect necrotic right temporal tip tissues to subside uncal herniation. A free pericranial flap was used to cover the foramen ovale intracranially. The temporalis muscle flap was rotated into infratemporal fossa to cover the foramen ovale extracranially.

Results: After wide debridement of the necrotic skull bone and the dura, the temporalis muscle flap was covered on the right temporal base. Though the embolization of right internal maxillary artery had been performed in prior surgery, this temporalis muscle flap still survived on the recipient site and CSF leak was improved.

Conclusion: The temporalis muscle flap is a useful and reliable flap to repair challenging defects of the lateral skull base. Having satisfactory size of the flap relative to the defect, the temporalis muscle flap still can survive and provide strong support even in the condition of prior embolization and radiotherapy had been performed on the recipient site.