Poor brain-tumor interface related edema generation and cerebral venous decompensation in parasagittal meningiomas

Background Parasagittal meningioma (PSM) has a high incidence of peritumoral edema and unclear pathogenesis. The venous compression theory has been proposed as a pathomechanism; however, this is controversial, and the various edema patterns have not been recognized. Objective We sought to establish the relationship between venous circulation status with different edema patterns in PSM and the neurologic outcomes of these different patterns. Methods We performed a retrospective study of 60 consecutive patients who underwent surgical treatment for PSM. Patients were divided into 3 groups: no edema, poor brain–tumor interface–related edema (PIRE), and strong brain–tumor interface–related edema (SIRE). Single-blinded observers scored venous circulation for each patient based on the degree of superior sagittal sinus (SSS) occlusion, the number of involved cortical veins, and venous collateral grade. PIRE and SIRE were analyzed using multivariate analysis. Finally, we evaluated the functional independence and mobility score for every patient. Results The PIRE group showed the highest rate of cerebral venous decompensation at 75% (n = 15) compared with 38.5% (n = 5) in the SIRE group and 22.2% (n = 6) in the no-edema group. We observed a significant correlation between venous decompensation and PIRE generation on multivariate analysis ( P  = 0.029). The PIRE group showed the worst immediate functional status, and the SIRE group had the best improvement in complete dependence rate (23%) at late evaluation. Conclusions The generation of PIRE, but not SIRE, may depend on venous decompensation in PSM. PIRE generation is predictive of worse neurologic outcome. Future studies into the pathogenesis of peritumoral edema should distinguish the different edema patterns.