FIG. 17.25. Clivus and petroclinal meningioma. This 60-year-old woman had undergone a limited subtotal removal of this tumor 12 years previously. No radiation therapy was given. Her only symptom, a mild sixth nerve paresis, and the size of the tumor on the scan have remained unchanged for 12 years. (A-D) CT scans after contrast, showing extension into the cavernous sinus and middle fossa.

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.

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)
  • CLIVUS AND PETROCLIVAL MENIGIOMAS (This File)
    • Management (This File)
    • Results (This File)
• References (File 22)

CLIVUS AND PETROCLIVAL MENIGIOMAS

(Meningioma Management, File 15)

Management

These tumors arise from the clivus or petroclival junction medial to the trigeminal nerve. They may grow out along the petrous pyramid or into the cavernous sinus and middle fossa. Large tumors displace or encase the basilar artery or its branches.

FIG. 17.26. Clivus meningioma. This 52-year-old woman presented with progressive hemiparesis and fifth cranial nerve symptoms. Extensive removal was followed by a full recovery of the hemiparesis. (A-D) CT scans after contrast, showing brainstem compression and extension into the @ddle fossa, cavernous sinus, and apex of the orbit.

The MRI scan gives a great deal of information about the tumor but angiography with both vertebral and carotid studies is usually needed to clarify the location of major arterial branches and the blood supply to the tumor.

The decision regarding the best treatment may be difficult because the patients may have large tumors with minimal symptoms (Fig. 17.25), the natural history is unknown, there is risk of significant morbidity associated with the surgery, and the long-ten-n results of the newer radiation therapy modalities are not known.

Surgery is indicated in patients with worsening symptoms of brainstem dysfunction (Fig. 17.26) and in younger patients with cranial nerve deficits. Patients with mild symptoms may be observed. Radiation therapy is used if an adequate decompression cannot be accomplished or there is regrowth after radical subtotal removal.

Several different approaches or a combination of approaches have been used with these tumors and they have been summarized in several publications (2, 6, 26, 27, 30, 43, 59, 60, 64). In general the approach selected depends on the configuration of the tumor and the direction of the growth. Mayberg and Symon (43) concluded that the combined subtemporal-posterior fossa approach gave the best results, as did Guthrie et al. (26). Various modifications of this approach have been described by Samii et al. (60) and Hakuba et al. (27). Al-Mefty and co-workers (2, 6) have described in detail a petrosal approach for these tumors.

Total removal is difficult because of the location of the tumor anterior to the brainstem, the involvement of cranial nerves, and the encasement of the vertebral-basilar arteries and their branches.

The key considerations in the operation include:

1. Careful planning of the approach.
2. Opening of the tentorium.
3. Intemal decompression of the tumor, taking great care to look for cranial nerves and arteries that may be engulfed by the tumor.
4. Dissection of tumor capsule, alternating between the supratentorial and infratentorial exposures.

Results

Results of the treatment of tumors in this location have not been as good as for meningiomas in general. Mayberg and Symon (43) found that 60% of patients were worse in the immediate postoperative period and only a small percentage were improved. About 70% eventually returned to independent existence, although many of those patients had a cranial nerve deficit. Total removal was possible in only nine of 35, but no evidence of recurrence was noted after

TABLE 17.14 Clivus Meningiomas
aRemoval		bOutcome		Complications		Recurrence
T	0	Good	5	Permanent deficit	4	2 Given radiation
RST	1	Fair	3
ST	9	Poor	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.

9 years. With microsurgical techniques a higher percentage of total removals has been reported (6, 27, 30, 60, 62). Samii et al. (60) reported that 83% of the patients had independent existence but nearly half had new postoperative complications, mainly Cranial nerve deflcits. There was no postoperative mortality. Total tumor removal was done in 71%. For the 52 patients reported by Javid and Sehkar (30) the functional results were not recorded but operative mortality was 4% and 30-40% of the patients had significant postoperative problems. Al-Mefty and Smith (6) reported total removal in 15 of 18 patients, with no postoperative mortality and apparently fairly good results.

In this series there were 10 patients, seven women and three men, ranging in age from 38 to 69 years (Table 17.14). All but one had a large tumor. One patient had a radical subtotal removal and nine a subtotal removal. Three required a ventriculoperitoneal shunt. In five patients the tumor not only involved the clivus and adjacent petrous bone but also had grown into the cavernous sinus and middle fossa. The involvement in the cavemous sinus and encasement of the basilar artery, its branches, and the lower cranial nerve prevented a more extensive removal.

Five patients had a good result that has continued for 2-14 years. They have not been given radiation therapy. Three patients had a fair result; two were worse after operation and one did not improve from a preoperative disability and also subsequently had a complication from radiation therapy given when the tumor started to regrow. No further growth has been seen in these patients. Two patients had a poor result, one because of recurrence in spite of multiple surgeries and radiation therapy and one with a postoperative hemiparesis.

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