The importance and timing of optic canal exploration and decompression during endoscopic endonasal resection of tuberculum sella and planum sphenoidale meningiomas.

BACKGROUND Suprasellar meningiomas often invade the optic canals (OCs). The feasibility of removing these tumors through a minimal-access endonasal route has been demonstrated, but the importance, safety, and timing of OC exploration and decompression are not well described. OBJECTIVE To create a simple decision-tree algorithm for OC exploration and decompression in the endonasal endoscopic surgery for planum sphenoidale and tuberculum sella meningiomas. METHODS We identified a consecutive series of 8 planum sphenoidale and tuberculum sella meningiomas resected endonasally. "Late" OC exploration and decompression was performed in 4 of 8 patients. The extent of resection, visual outcome, and complications were recorded. RESULTS Five patients had OC invasion on magnetic resonance imaging. Endoscopic inspection did not reveal additional OC invasion. The OC was opened bilaterally in 2 patients and unilaterally in 2 patients. Gross total resection was achieved in 6 of 7 patients in whom it was the goal. Vision improved in 3 patients (3 of 3 OCs opened) and was stable in 4 (1 of 4 OCs opened). In 1 patient, the bitemporal hemianopsia improved, but there was unilateral deterioration (no OC invasion) because the tumor was extremely adherent to 1 optic nerve. After an average follow-up of 20.9 months, all patients had an Glasgow Outcome Scale score of 5, and there were no cerebrospinal fluid leaks. CONCLUSION Exploration and decompression of the OC are feasible, safe, and important to optimize visual outcome and to minimize recurrence in planum sphenoidale and tuberculum sella meningiomas resected endonasally. It may not be important to open the canal early during surgery because tumor debulking can be performed without manipulating the optic nerves. Early decompression, however, is technically feasible.