Novel Surrogate Indicators of Intracranial Meningioma Consistency and Outcomes After Resection

Tumor consistency affects resection and outcomes in meningioma surgery. This study aimed to identify predictors of tumor consistency using the Zada grading scale and assess their association with surgical outcomes and prognosis.

We retrospectively reviewed patients aged 18 years and older who underwent intracranial meningioma resection from 2014 to 2024, with ≥1 year of follow-up. Tumors were graded into 5 consistency types per Zada's criteria. Data on demographics, imaging (T2-weighted MRI), histology, and surgical outcomes were collected. Signal intensity ratios between tumor and cortex were calculated. Statistical analyses included analysis of variance, linear regression, receiver operating characteristic analysis, and Cox regression for progression-free survival (PFS).

Five hundred and fifty-four patients (67.7% female; mean age 58.1) were included. Firmer tumors were associated with longer operative times (492 vs 382.3 minutes for type 4 vs type 2, P < .0001), higher subtotal resection rates (58.6% vs 15%, P < .0001), and increased psammoma body prevalence (17.2% vs 3%, P < .0001). Adherence to surrounding structures correlated with firmness (β = 0.2953, P = .0046). Softer tumors showed higher SI ratios (1.2 vs 0.95, P = .0027), with an area under the curve value of 0.6888. SI thresholds <0.6533 and >1.547 predicted firm and soft tumors with 95% sensitivity respectively. Type 2 tumors had the lowest complication rates (1.56%), whereas type 5 had the highest reoperation rates (33.3%). Firmer tumors were linked to worse PFS (P = .0247), primarily due to lower resection extent (β = -0.8752, P = .0007).

Higher meningioma consistency is linked to surgical difficulty and poorer PFS. Psammoma bodies, tissue adherence, and SI ratios are promising surrogate markers to guide surgical planning.