What is the proximity of the superior sagittal sinus to a frontal interhemispheric falx meningioma?

Proximity of Superior Sagittal Sinus to Frontal Interhemispheric Falx Meningiomas

Frontal interhemispheric falx meningiomas are typically located in very close proximity to the superior sagittal sinus, often directly abutting or invading it, as these tumors arise from the falx cerebri which runs immediately adjacent to the sinus along the midline. 1, 2

Anatomical Relationship

• Falx meningiomas originate from the dural fold (falx cerebri) that lies directly between the two cerebral hemispheres and runs parallel to the superior sagittal sinus throughout its length 3, 4
• The superior sagittal sinus courses along the superior attachment of the falx cerebri, making it anatomically inseparable from falcine meningiomas in the frontal region 2
• In the frontal location specifically, the distance between the tumor and the superior sagittal sinus is often measured in millimeters or the tumor may directly contact the sinus wall 2

Clinical Significance of Sinus Proximity

• When a meningioma is identified in close proximity to the sagittal sinus, additional MRV or CTV imaging is indicated to assess the integrity and patency of the dural venous sinus 1
• Postcontrast MRV and CTV are complementary in evaluating whether the sinus is patent, partially invaded, or completely occluded 1
• Approximately 108 cases of parasagittal meningiomas invading the superior sagittal sinus demonstrated that these tumors can range from partial wall invasion to complete sinus occlusion 2

Surgical Implications Based on Sinus Relationship

• If the sinus is partially invaded, it can be opened to obtain complete resection while attempting to preserve sinus patency 2
• If the sinus is completely obstructed by tumor, the involved portion of the sinus can be resected entirely without need for reconstruction 2
• Preservation of cortical veins draining into the superior sagittal sinus is critical, as these may offer important collateral drainage pathways 2

Imaging Assessment Requirements

• MRI with contrast is essential for defining the relationship between the tumor and the superior sagittal sinus, showing characteristic dural tail sign and the extent of sinus involvement 5, 6
• The superior sagittal sinus serves as a preferred reference region for quantitative assessment in somatostatin receptor PET imaging when evaluating meningiomas 1
• Vascular flow characterization with time-resolved MRA or digital subtraction angiography may provide additional information regarding venous drainage patterns 1

Common Pitfall

• Underestimating the surgical complexity of parasagittal/falcine meningiomas due to their intimate relationship with critical venous anatomy can lead to catastrophic outcomes including venous infarction 7, 2
• Failure to obtain preoperative venous imaging (MRV or CTV) before attempting resection of a frontal falx meningioma represents inadequate surgical planning 1