Surgical Corridor Selection in Deep-Seated Midline Meningiomas: A Propensity-Matched MRI Study of Cortical Injury

Abstract Background Optimal surgical corridor selection for deep-seated midline meningiomas remains controversial, particularly regarding the balance between adequate exposure and preservation of surrounding cortex. Comparative data quantifying postoperative cortical injury between transcortical and interhemispheric approaches are limited. Methods We conducted a retrospective single-center study of patients with deep-seated midline meningiomas treated between 2002 and 2023. Cortical injury was quantified using early postoperative contrast-enhanced MRI and measured independently by two neuroradiologists. Propensity score matching (1:1, caliper = 0.2) was performed based on age, sex, and tumor location to compare transcortical and interhemispheric corridors. The primary endpoint was MRI-defined cortical injury burden (cm²). Secondary outcomes included complications, reoperation, mortality, extent of resection, and recurrence-free survival. Results Among 38 patients with radiologically assessable cortical injury (13 transcortical, 25 interhemispheric), propensity score matching yielded 13 balanced pairs. Mean cortical injury was significantly lower with the transcortical approach both before matching (0.96 ± 0.42 cm² vs 1.96 ± 1.35 cm²; p < 0.001) and after matching (0.96 ± 0.42 cm² vs 1.65 ± 1.10 cm²; p = 0.003). Perioperative complication and reoperation rates were comparable between matched groups, whereas mortality occurred only in the interhemispheric cohort without reaching statistical significance. Recurrence was uncommon, with a 5-year recurrence-free survival rate of 98.2%. Conclusions In deep-seated midline meningiomas, surgical corridor selection is associated with measurable differences in cortical preservation. The transcortical approach demonstrated significantly lower MRI-defined cortical injury without compromising short-term clinical or oncological outcomes. These findings support selective use of transcortical access when anatomical conditions are favorable and highlight the importance of corridor-based decision-making in meningioma surgery.