The Relevance of Simpson Grade Resections in Modern Neurosurgical Treatment of World Health Organization Grade I, II, and III Meningiomas.

Objective: The Simpson grading system has played an important role in surgical resections of meningiomas. The aim of this study was to determine if this grading system predicts meningioma recurrence in a modern cohort of patients with tumors of all World Health Organization grades.
Methods: Adult patients who underwent primary, nonbiopsy resection of a meningioma at a tertiary care institution between 2007 and 2015 were retrospectively reviewed. Stepwise multivariate proportional hazard analyses were used to identify associations with recurrence after resection. Log-rank analyses were used to compare Kaplan-Meier plots for time to recurrence between each Simpson grade.
Results: Of 572 patients who met inclusion criteria, 72 (12.6%) presented with recurrence. Factors associated with recurrence after gross total resection (Simpson grades I-III) were non-World Health Organization grade I (hazard ratio [HR] [95% confidence interval (CI)] 6.215 [2.864-12.419], P < 0.0001) and preoperative neurologic deficits (HR [95% CI] 2.862 [1.512-5.499], P = 0.001). Factors associated with recurrence after subtotal resections (Simpson IV) were African American race (HR [95% CI] 2.776 [1.232-5.890], P = 0.02) and parafalcine location (HR [95% CI] 3.956 [1.624-8.775], P = 0.004). Simpson grade was not an independent risk factor for recurrence.
Conclusions: Identification and consideration of factors associated with recurrence after gross total or subtotal resections may help guide treatment strategies for patients with meningiomas.
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