Endoscopic Craniofacial Approach for Intracranial Polyposis: The “Blue–Sky Technique”

Massive sinonasal polyposis associated with skull base dehiscence and intracranial extension is a difficult disease to treat. Conventional transnasal or transfacial techniques can result in dural injury, cerebrospinal fluid (CSF) leak and infection. We describe our experience with a combined neurosurgical–endoscopic technique that protects the meninges. Five patients with massive sinonasal polyposis extending intracranially through skull base dehiscence were reviewed retrospectively. The minimum follow–up was 2 years. A frontal craniotomy was performed through a bicoronal approach. The dura was carefully separated from all infectious material at the floor of the anterior cranial fossa. The frontal lobe with the intact meninges was elevated off the anterior cranial floor. A sheet of blue plastic material was inserted under the frontal lobe from the craniotomy site to the planum sphenoidale. Next, a transnasal endoscopic ethmoidectomy, sphenoidectomy, and frontal sinusotomy were performed to remove the inflammatory processes. The blue plastic material was visible through any existing or potential skull base dehiscence, thus providing visual protection for the dura and brain. All gross disease was removed from the frontal, ethmoid, and sphenoid skull base regions in the 5 patients without dural injury. None of the patients developed a CSF leak or meningitis. Two patients developed recurrent polyposis limited to the sinuses without intracranial extension. The endoscopic craniofacial approach with the “Blue–Sky” protective technique offers a safe method for completely removing massive sinonasal polyposis associated with an intracranial extension.