Relevance of the Foramen of Vesalius for Preoperative Tumor Embolization in Skull Base Meningioma.

OBJECTIVE: The objective of this study was to investigate the role of the foramen of Vesalius (FV) in the pathogenesis of skull base meningioma by analyzing data from various multi-image modalities. METHODS: For this single-center retrospective study, 39 consecutive patients with skull base meningioma who underwent tumor resection between January 2020 and March 2023 were enrolled. The anatomical and pathological characteristics of the FV were evaluated using computed tomography and 3-dimensional digital subtraction angiography. The clinical significance of the FV in tumor hemodynamics and treatment, such as preoperative tumor embolization, was investigated using the 3-dimensional digital subtraction angiography/computed tomography fusion images. RESULTS: We identified FV in 52% (17/27) of the finally included patients. In 10 (30%) patients, the FV was found bilaterally with no significant variation in appearance between the healthy and tumor-affected sides (P = 0.786). The mean FV diameter was significantly larger on the tumor-affected side (P = 0.010). No significant anatomical differences, like duplication and partial assimilation with the foramen ovale, were observed between the 2 sides. The FV was involved in venous skull base perfusion around the tumor in 9 cases. In 4 cases where it was the pathway for tumor feeders, preoperative tumor embolization via the FV resulted in disappearance of the tumor stain. No complications associated with endovascular treatment were observed. CONCLUSIONS: This study elucidated the anatomical asymmetry of the FV and its role in the hemodynamics of skull base meningioma. Our findings highlight the significance of performing anatomical and pathological evaluations of the FV in determining treatment strategies, including preoperative embolization, for skull base lesions.

Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14 days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4 days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.