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.