=====Kobayashi tumor removal grading system=====
Grade I—complete microscopic removal of tumor & dural  attachment w/ any abnormal bone  

Grade II—complete microscopic removal of tumor w/ diathermy coagulation of its dural attachment 

Grade IIIA—complete microscopic removal of intra- & extradural tumor w/o resection or coagulation of its dural attachment 

Grade IIIB—complete microscopic removal of intradural tumor w/o resection or coagulation of its dural attachment or any of its extradural extensions 

Grade IVA—intentional subtotal removal to preserve CNs or blood vessels w/ complete microscopic removal of attachment 

Grade IVB—partial removal leaving tumor ≤10% in vol 

Grade V—partial removal leaving tumor >10% in vol, or decompression w/ or w/o biopsy 

((DeMonte F, Smith HK, Al-Mefty O: Outcome of aggressive removal of cavernous sinus meningiomas. J Neurosurg 81:245 –251, 1994))