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Management of Meningiomas
File 18: CEREBELLAR CONVEXITY MENINGIOMA

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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.


Disclaimer: The information and reference materials contained herein are intended solely to provide background information. They were written for an audience of physicians. They are in no way intended to constitute medical advise. For medical advise a physician must, of course, be consulted.
Meningioma CAT scan
FIG. 17.32. Cerebellar convexity meningioma. This 65 year-old woman had increasing difficulty in walking. Total removal was followed by full recovery. The CT scan shows a large tumor arising from the junction of the petrous and cerebellar convexity dura on the right side. Cerebellar tissue has been compressed anteriorly and medially.

Contents


CEREBELLAR CONVEXITY MENINGIOMAS

(Meningioma Management, File 18)

Management

These meningiomas can be divided into two groups. One arises from the dura over the posterior convexity of the cerebellum and the other arises in the angle between the petrous and convexity dura and may include the wall of the sigmoid and lateral transverse sinuses (FIG. 17.32). These meningiomas are usually separated from the cranial nerves by cerebellar tissue but in very large tumors there may be only a thin layer of arachnoid. MRI gives most of the information the surgeon needs. Angiography may be indicated to determine the status of the venous sinuses. Surgery is indicated when the patient has neurological symptoms, usually headache or progressive cerebellar signs. Radiation therapy has not been used.

For most patients I prefer to use the same approach as described for cerebellopontine angle tumors. In some patients the exposure extends above the sinus or into the mastoid. Several different approaches and incisions have been reviewed by Kobayashi and Nakamura (32). The key considerations in the operation are the same as those outlined for meningiomas in general (see "General Considerations in Management").

If the sigmoid or transverse sinus is occluded this is resected. In most patients the sinuses are open. In these patients a layer of dural attachment over the sinus can often be removed.

Results

TABLE 17.17 Cerebellar Convexity Meningiomas
aRemoval bOutcome Complications Recurrence
T 5 Good 6 None None
RST 1 Fair 0
ST 0 Poor 0
aT, total removal
RST, radical subtotal removal
ST, subtotal removal
bGood, free of major neurological deficit
and able to return to previous activity level
Fair, independent but not able to return to full activity
because of new neurological deficit or significant
preoperative deficit that did not fully recover
Poor, dependent.
In this series there were six patients, five women and one man, ranging in age from 56 to 75 years, with one over 70 years of age (Table 17.17). Three of these lesions arose from the cerebellar convexity dura and three were over the sigmoid sinus. A gross total removal was done in five and a radical subtotal removal in one, with tumor left in the wall of the sinus. All made a full recovery. There have been no recurrences. Only a few small series of patients have been reported. Martinez et al. (40) summarized the reports to 1982. Kobayashi and Nakamura (32) noted that, with the advent of microsurgical techniques, the results have generally been good to excellent.

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