Falx meningiomas are often bilateral and are completely concealed by the overlying cerebral cortex. These meningiomas can also be classified into anterior, middle, and posterior thirds and the clinical presentation is the same as described for parasagittal meningiomas.
For meningiomas of the falx the same position, scalp incision, and bone flap are used as described for parasagittal meningiomas. Often the tumor is bilateral but is usually much larger on one side. The dura is opened to I to 2 cm from the midline, with the exposure planned in relation to the cortical veins draining to the sagittal sinus. Arachnoid and pacchionian granulation attachments are divided. It is only necessary to retract the medial cerebral cortex I to 2 cm from the falx to expose the tumor. In some cases a bridging vein can be freed from the cortex for a few millimeters to give the required exposure without sacrificing the vein. A selfretaining retractor is placed. In the anterior third it is usually possible to take the draining veins and the sagittal sinus if necessary to complete the resection.
The key to the operation is to carry out an extensive internal decompression of the tumor with the ultrasonic aspirator and gradually draw the capsule into the area of decompression. Sometimes the tumor is transected parallel to the falx so the capsule can be more easily mobilized. In some patients a bilateral exposure is required. At some point in the operation, depending on the size and configuration of the tumor, the falx is divided well away from the tumor attachment. The inferior sagittal sinus can be occluded. Great care must be taken not to injure the pericallosal and callosomarginal arteries.
A good outcome is around 95%. A total removal can be achieved in 90% of patients. Subtotal removal could be due to tumor involvement with the anterior cerebral artery and other causes. 20% of patients has significant temporary worsening but recover over weeks to months. Recurrence rate is very low.