Significance of the simultaneous combined transcranial and endoscopic endonasal approach for prevention of postoperative CSF leak after surgery for lateral skull base meningioma.

Lateral skull base meningiomas, particularly sphenoorbital meningiomas, sometimes extend extremely widely into adjacent structures including the paranasal sinuses. For endonasal skull base reconstruction using a vascularized nasoseptal flap for prevention of postoperative cerebrospinal fluid (CSF) leak, the simultaneous combined transcranial and endoscopic endonasal approach was applied for resection of these extensive tumors. We performed a retrospective review of four patients treated with the simultaneous combined transcranial and endoscopic endonasal approach for resection of lateral skull base meningiomas. Preoperative characteristics, tumor extent, extent of resection, complications, and postoperative outcomes were analyzed. The tumor extended into the paranasal sinus, infratemporal fossa, and pterygopalatine fossa in all patients. Extracranial extension into the cavernous sinus or superior orbital fissure was detected in two and three patients, respectively. In one patient without extension into the cavernous sinus and superior orbital fissure, gross total resection was achieved, whereas in the other three patients, subtotal resection was performed, and small residual masses of the tumor remained in the cavernous sinus or superior orbital fissure to minimize the risk of postoperative ocular nerve damage. No patients experienced postoperative CSF leak. The simultaneous combined transcranial and endoscopic endonasal approach is useful for a subgroup of patients with lateral skull base meningiomas for prevention of postoperative CSF leak. Particularly in recurrent cases in which vascularized flaps from the transcranial side are likely unavailable due to prior tumor resection, this combined approach is worth considering depending on tumor extension into the paranasal sinus.