Table 1. Surgical decision making for keyhole meningioma removal.

Meningioma Location	Factors for Surgical Decision Making	Approach Selection
Olfactory Groove/Anterior Planum	Olfaction preservation	Supraorbital
Posterior Planum/Tuberculum Sella	1. Proportion of tumor above the planum 2. Sellar depth 3. Tuberculum angle 3. Optic canal Invasion 4. Extent of tumor extension lateral to supraclinoid ICA 5. Maximal tumor diameter	Majority of tumor below planum, deep sella, steep (acute) tuberculum angle, minimal lateral extension, small size (under 3 cm): Favor Endonasal Medial optic canal invasion: Favor Endonasal Majority of tumor above planum, shallow sella, broad tuberculum angle, significant lateral extension, lack of medial optic canal invasion, larger size (over 3 cm): Favor Supraorbital
Clinoidal	Extension into middle fossa	Predominantly above the lesser wing: favor Supraorbital Predominantly within the middle fossa: favor Mini-pterional
Sphenoid Wing	Angle of Attack with respect to the Optic Chiasm and Supraclinoid Carotid	Mini-pterional
Spheno-Orbital/Spheno Cavernous	Angle of attack with respect to the optic chiasm and supraclinoid carotid artery	Mini-pterional ± orbitotomy
Cavernous Sinus/ Meckel’s Cave, Spheno-cavernous	Surgical goal of decompression	Endonasal
Petroclival/ CP Angle/ Foramen Magnum	Clival and CP Angle component	If substantial petrous and posterior CP angle component posterolateral to CN VI: Favor Retromastoid If substantial clival component more anterior: Favor Endonasal ± Retromastoid
Tentorial	Proximity to convexity	If away from convexity–Suboccipital sitting gravity-assisted endoscopic-assisted or fully endoscopic
Falx	Abutting primary motor or sensory cortex with overlying ipsilateral cortex	Contralateral gravity-assisted trans- falcine endoscopic