Grade zero removal of supratentorial convexity meningiomas.

Although meningiomas are benign intracranial tumors, their frequency of recurrence after surgery has not been as low as expected. The recurrence rate of meningiomas is clearly related to the degree of tumor removal. Simpson Grade I removal, which entails excising the tumor and its dural and sinus attachments, is associated with the lowest rate of recurrence. To further minimize the recurrence of convexity meningiomas, we removed an additional dural margin of about 2 cm around the tumor (Grade 0 removal). For tumors involving bone, we removed the hyperostotic bone with a healthy margin and pericranium in en bloc resection. Between 1982 and 1992, 37 patients (15 men, 22 women) with an average age of 52.1 years were operated on by the above technique. Nineteen had a follow-up period of more than 5 years. To date, no tumors have recurred and no morbid incidences have occurred with this maneuver. We believe that the recurrence rate of convexity meningiomas can be diminished by including in the resection a margin of dura that might harbor a foci of tumor cells.