FIG. 17.16. Falx meningioma. This 45-year-old woman presented with headache and a feeling of heaviness and progressive loss of function in the right lower extremity. After total removal there was a temporary increase in hemiparesis that was followed by recovery with minimal residual weakness. (A and B) MRI coronal (A) and sagittal (B) TI images after gadolinium show the left falx tumor in relation to the cerebral tissues. (C) The MRI axial T2 image shows the displacement and course of the anterior cerebral artery and the edema in the adjacent brain areas. (D) An angiogram is needed to see the position of the cortical veins in order to plan the operation.

by ROBERT G. OJEMANN, M.D.

© Congress of Neurological Surgeons Honored Guest Presentation
Originally Published Clinical Neurosurgery, Volume 40, Chapter 17, Pages 321-383, 1992
Used with permission of the Congress of Neurological Surgeons.

HTML Editor: Stephen B. Tatter, M.D., Ph.D.

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Contents

• Introduction to the therapy of Meningiomas (File 1)
• General Considerations in Management of Meningiomas (File 1)
  • Surgery of Meningiomas (File 1)
  • Radiation Therapy of Meningiomas (File 1)
  • Observation of Meningiomas (File 1)
• Summary of Dr. Ojemann's Meningioma Series (File 1)
  • FALX MENINGIOMAS (This File)
    • Management (This File)
    • Results (This File)
• References (File 22)

FIG. 17.17. Falx meningioma. This 50-year-old woman presented with a mild frontal lobe syndrome. Complete removal was followed by a good recovery. (A and B) MRI axial (A) and coronal (B) T1 images after gadolinium, showing a large right anterior falx meningioma. Note the displacement of the anterior cerebral artery to the left.

FALX MENINGIOMAS

(Meningioma Management, File 12)

Management

Meningiomas arising from the falx can also be classified into anterior, middle, and posterior thirds, as described for parasagittal meningiomas (20, 35). These tumors are completely covered by the overlying cortex and tend to grow predominately into one cerebral hemisphere but are often bilateral. In some patients the tumor grows into the inferior edge of the sagittal sinus.

MRI defines the tumor and may give information relative to the relationship of the anterior cerebral artery branches (Fig. 17.16, A-C). However, in patients with tumors at and posterior to the coronal suture an angiogram is needed to clarify this relationship as well as the position of the cortical veins, which is important in planning surgery (Fig. 17.16D).

FIG. 17.18. Falx meningioma. Exposure of the tumor between two cortical veins. Only enough retraction to expose a little more than 1 cm of the tumor capsule is required.

The indications for treatment are the same as outlined for parasagittal meningiomas. The details of the operative procedure have been described (26, 35, 38, 42, 47). Most of the key considerations are the same as those described for parasagittal meningioma. Additional considerations include the following.

1. Exposure of the tumor is planned in relation to the draining cortical vein for tumors in the middle and posterior thirds of the falx (Fig. 17.16D). In the anterior third it is usually possible to take the draining veins and the sagittal sinus, if necessary, to complete the resection (Fig. 17.17).
2. It is important to avoid excessive retraction of the cerebral cortex. Only I cm, or at most 2 cm, of the surface of the tumor needs to be seen (FIG. 17.18).
3. The falx is divided around the area of attachment or the tumor is transsected parallel to the falx so the bulk of the tumor can be mobilized.
4. An extensive internal decompression is done so the capsule can be gradually drawn into the area of the decompression.
5. The falx attachment is excised. If tumor extends to the opposite side, it can usually be removed through the opening in the falx.

Results

FIG. 17.19. Falx meningioma. This 90-year-old woman presented with headaches and deteriorating mental function over several months. She had been living alone and had normal mental function. Removal was followed by full recovery. (A-D) CT scans after contrast, showing a right frontal meningioma with edema. At operation there was a thin layer of cortex over the tumor.

There were 14 patients, including nine women and five men ranging in age from 10 to 90 years, with three over 70 years of age (Table 17. 1 1). Of the 14 patients 13 had a good outcome and one was better but had residual preoperative deficits. A total removal was done in 12 patients, one had subtotal removal because of involvement with the anterior cerebral artery, and one a radical subtotal removal because of tumor in the inferior wall of an open sagittal sinus. Three patients had significant temporary worsening, which recovered over weeks to months. There has been no evidence of recurrence in any patient, including those with subtotal removal, over 8 years.

The largest tumor (Fig. 17.17) and the oldest patient with an intracranial tumor (Fig. 17.19) in this series involved falx meningiomas. As noted in the introduction, age by itself has not been a limiting factor in recommending surgical treatment. This last patient lived alone and had normal mental function and good medical condition prior to the onset of a frontal lobe syndrome. Removal of the meningioma was followed by a full recovery and independent living.

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