Factors influencing the recurrence rate of intracranial meningiomas after surgery.

The postoperative recurrence rate was examined in 242 patients with intracranial meningiomas to identify correlations with age, location, histology, or extent of surgery (Simpson's grade). There was no significant difference in the recurrence rate among the histological subtypes, but malignant meningiomas and hemangiopericytomas tended to recur earlier. Anterior basal meningiomas demonstrated a higher recurrence rate, but this depended on the feasibility of complete surgical removal. The recurrence rates significantly decreased in the order Simpson's grade I surgery, grade II or III surgery, and grade IV surgery (p < 0.001). These results indicate that the most important factor to influence recurrence is the extent of surgical removal.