Table 1 Simpson grading system for removal of meningioma

I

Macroscopically complete removal with excision of the dural attachment and abnormal bone.

II

Macroscopically complete removal with endothermic coagulation of dural attachment.

III

Macroscopically complete removal without coagulation of dural attachment or its extradural extensions (for example, hyperostotic bone).

IV

Partial removal leaving small part of the tumor in situ.

V

Biopsy.