Transcranial Combined Neurorhinosurgical Approach to the Paranasal Sinuses for Anterior Skull Base Malignancies

Objective: Various transcranial and transfacial approaches have been described and each claims to provide the best exposure to the anterior skull base. Similarly, each approach claims the best outcomes following the resection of anterior skull base malignancies. We have always advocated a combined neurorhinological approach for the management of paxanasal sinus malignancies that infiltrate the skull base, such as esthesioneuroblastomas. Materials and methods: At the outset, the technique was developed on cadaver specimens, imitating the limitations that might be imposed in the real-life situation when undertaking endoscopic sinus surgery. Additional exposure of the anterior cerebral fossa was achieved using a classical bifrontal approach. Starting with endoscopic or microscopic unroofing of the ethmoids, all relevant landmarks were identified. The frontal, sphenoid, and maxillary sinuses were then opened using endoscopic techniques. Results: The dissections proved that a broad exposure of the anterior skull base could be combined with clear endoscopic visualization of the nasal cavity and of all the paranasal sinuses from above. This facilitated complete eradication of lesions from the sinuses cavities, their walls, and the intracranial tumor. Discussion: The combined neurorhinosurgical transcranial approach to the anterior skull base and nasal and paranasal sinuses, avoiding trans-facial approaches, enables a multidiciplinary team to resect malignant tumors of the anterior skull base directly without unnecessary destruction of facial structures. It appears to provide better access than other more destructive methods like midfacial degloving or subfrontal approaches. Our single-stage approach also facilitates safe and effective reconstruction of the skull base. The technique can be employed for tumors of all sizes and is also used for orbital resections and decompression of the optic nerve and chiasma.