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Management of Meningiomas
File 2: TUBERCULUM SELLAE MENINGIOMAS

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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.

Contents


  • MRI of Meningioma
    FIG. 17.3. Tuberculum sellae meningioma. This 36-year-old presented with decreased vision. After operation, vision was normal. (A) CT axial images, showing a large meningioma. (B) MRI axial TI image after gadolinium, showing the small residual tumor adherent to the anteiior cerebral arteries after a radical subtotal removal. When the residual tumor started to grow on follow-up MRI, radiation therapy was given, with arrest of the growth.

TUBERCULUM SELLAE MENINGIOMAS

(Meningioma Management, File 3)

Managment

MRI outlines the tumor and its relationship to the optic nerves, chiasm, and internal carotid artery and its branches (48). In most patients angiography is not needed and there is no indication for embolization.

The indication for surgical treatment is usually worsening vision. Surgical removal of the tumor gives the best chance for relief of symptoms and the best possibility of curing the patient. Surgery should also be considered in an asymptomatic patient because of the likely probability of future visual symptoms. When large tumors involve the optic apparatus, internal carotid, or anterior cerebral arteries with dense adherence, it may be wise to leave a small amount of tumor (radical subtotal removal). Radiation therapy is recommended when there has been a subtotal removal with an inadequate decompression or there is evidence of recurrence on MRI after radical subtotal removal (Fig. 17.3). 1 have tended to wait on this recommendation for evidence of regrowth unless the operation has been done for recurrence.

In general, I prefer a right subfrontal exposure, elevating the frontal lobe just in front of the sphenoid wing (Fig. 17.4A and B) (47, 54, 55). A left subfrontal exposure is utilized when the tumor bulk is greater on that side and occasionally a bifrontal exposure is used for large tumors. Guthrie et al. (26), Andrews and Wilson (7), and Grisoli et al. (22) have also used the right subfrontal approach unless the visual loss is greater on the left side. Logue (37) and Symon (74) use a unilateral right subfrontal exposure but approach the tumor along the midline. Al-Mefty and Smith (5) use a unilateral supraorbital exposure. For large tumors, Al-Mefty et al. (3) use a bifrontal craniotomy. Symon (74) resects a portion of the frontal lobe.

  • Line drawings of meningioma resection
    FIG. 17.4. Tuberculum sellae meningioma. (A) Incision and bone flap for unilateral subfrontal exposure. (B ) The tumor may surround a portion of the right optic nerve, displace the internal carotid artery laterally, and involve the anterior cerebral arteries. (C) The tumor is opened along its attachment to the tuberculum, the blood supply is interrupted, and an internal decompression is done. The attachments to the right optic nerve are being separated. (D) The left optic nerve is exposed after the decompression. The tumor is being separated from the anterior cerebral artery complex.

The key considerations in the operation include:

  1. Internal decompression of the tumor and interruption of the blood supply along the tuberculum (Fig. 17.4C).
  2. Careful microsurgical dissection. As the tumor grows, it elevates and displaces the optic nerves laterally and may surround the nerves (Fig. 17.4B). The internal carotid artery is also displaced laterally and may be engulfed by tumor. Growth may extend posteriorly above the chiasm to involve the anterior cerebral arteries (FIG. 17.4D) and in large tumors compresses the hypothalamus.
  3. Awareness that if the tumor is large the pituitary stalk is displaced posteriorly and the tumor may extend into the interpeduncular cistem but there is usually an intact arachnoid membrane.
  4. Removal of the involved dura.
  5. If needed, exposure of the optic canals to remove an extension of tumor.

Results

Table 17.2 records the results for 21 patients with tuberculum sella meningioma. There were 18 women and three men ranging in age from 20 to 77 years, with five over 70 years of age. The indication for surgery in all but two patients was worsening vision. In one of these it was a frontal lobe syndrome and in the other an asymptomatic recurrence seen on 'CT of an atypical meningioma previously operated on at another hospital. In 18 of the 21 patients there was a good outcome. The fair result was in a lady who had already had four operations for her tumor before we saw her. Mild frontal lobe symptoms did not improve and vision was worse. The two poor results were in a 73-year-old woman with a severe frontal lobe syndrome that did not improve and in a 61-year-old dentist with an atypical meningioma who had tumor growing under his optic nerve into the optic canal. He did well for 5 years after radical subtotal removal and radiation therapy and then the tumor recurred with rapid growth; he did improve with further surgery.

After operation vision was improved in 12 patients, the same in seven, and worse in only two. Two patients had transient changes in mental function that recovered. When diabetes insipidus occurred, it was transient.

The patients with radical subtotal removal had a small area of tumor left adherent to the internal carotid or anterior cerebral arteries or under the optic nerves (Fig. 17.3B). Subtotal removal

    TABLE 17.2 Tuberculum Sellae Meningiomas
    aRemoval bOutcome Vision Recurrence
    T 10 Good 18 Better 12 2 after RST
    RST 8 Fair 1 (1) Same 7 1 after ST
    ST 3 Poor 2 (2) Worse 2
    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.

was done in two patients with recurrent tumors in whom the optic and arterial structures were encased in tumor. One elderly patient also had a subtotal removal.

Radiation therapy was used in six patients, one with subtotal removal, two with radical subtotal removal in whom postoperative scans showed beginning regrowth of tumor, and three patients where operation had been done for recurrence. In five of these six patients there has been no evidence of further growth during a follow-up period of 2-8 years. One, who had the optic nerve and chiasm encased in tumor, has shown reduction in size of the tumor and dramatic improvement in vision in one eye. In the last patient, an atypical meningioma continued to recur in spite of radiation therapy and further surgery.

The series of Symon and Rosenstein (75), Andrews and Wilson (7), and Al-Mefty and Smith (5) also reported good results from surgery. A long history of visual impairment does not preclude good recovery but improvement is more likely when the history is of relatively short duration (21).

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Disclaimer About Medical Information: The information and reference materials contained herein is intended solely for the information of the reader. It should not be used for treatment purposes, but rather for discussion with the patient's own physician. All visitors to this and associated sites from the Neurosurgical Service at MGH agree to read and abide by the the complete terms of legal agreement found at the Neurosurgery "disclaimer & legal agreement." See also: the MGH Disclaimer, the MGH Privacy Policy, and the MGH Interactive Program Disclaimer - Copyright 2000.
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