Grade Zero Removal of a Pterional Meningioma: 2-Dimensional Operative Video

The recurrence rate of meningiomas is directly related to the degree of tumor removal, as described by the Simpson(1) grading scale. According to this scale, grade I removal (macroscopically complete including dural attachment and abnormal bone) is associated with the lowest rate of recurrence.(2-4) However, recurrence rates are still somewhat higher than might be sought for what is most often a benign process. Borovich and Doron(S) described the concept of regional multicentricity including tumor cells centimeters beyond the dural attachment and postulated that this may account for "unexpected relapses." Tumor invasion of the dura has been detected in 88.3% of a series of 179 meningiomas, with 94.9% of those being up to 2.5 cm from the tumor attachment.(6) Similarly, removal of hyperostotic invaded bone is necessary to maximize resection.(7) We described a strategy of more aggressive resection termed "grade 0 removal" in patients with convexity and falcine meningiomas.(8,9) In this technique, an additional dural margin of about 2 cm around the tumor is excised, as is any bone suspicious for invasion guided by neuronavigation. Pterional meningiomas toe the line between convexity and skull base meningiomas. They typically invade the adjacent bone and show dural spread and put the concept of grade 0 removal to the ultimate test. Here, we present the case of a pterional meningioma that was removed using the above technique. The patient consented to surgery. Image at 1:48 (c) Ossama Al-Mefty, published with permission.