File 2:MEDIAL SPHENOID WING (CLINOIDAL) MENINGIOMAS
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G. OJEMANN, M.D.
© Congress of Neurological Surgeons Honored
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.
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
| FIG. 17.5. Medial sphenoid
wing meningioma. This 59-year-old man presented with loss
of vision in his right eye, increasing difficwty with memory,
and a change in personality. Extensive subtotal removal was
followed by a recovery of his mental function but no improvement
in vision. (A and B) MRI axial (A) and coronal (B)
TI images after gadolinium, showing the right internal carotid,
middle cerebral, and anterior cerebral arteries surrounded by
tumor. Edema in the adjacent brain areas, hydrocephalus, and
severe compression of neural structures are noted. (C)
Angiograin (lateral view) shows the elevation and encasement
of the internal carotid artery.
MEDIAL SPHENOID WING (CLINOIDAL) MENINGIOMAS
(Meningioma Management, File 4)
These meningiomas involve the region
of the anterior clinoid, adjacent medial sphenoid wing, superior
orbital fissure, and cavemous sinus. They may grow into the orbit.
The tumor often encases the intemal carotid and proximal middle
and anterior cerebral arteries as well as the optic nerve and may
compress or provoke edema in the temporal or frontal lobes.
MRI outlines the extent of the tumor
and shows the relationship to the arterial structures (Fig. 17.5,
A and B). It is often hard to define the optic nerves
and chiasm. Angiography is usually needed to determine the extent
of encasement of the internal carotid artery and its branches (Fig.
17.5C). On rare occasions, especially with recurrence of an aggressive
tumor, internal carotid occlusion is considered prior to surgery.
Embolization of external carotid artery branches may occasionally
The treatment decisions are often
difficult. Prior to the development of CT and MRI and microsurgical
techniques it was difficult to remove these tumors completely and
there was significant morbidity. With the development of microsurgical
techniques, some of these tumors now can be extensively removed.
It remains to be established in the long term which patients benefit
more from this extensive surgery with the increased risk of morbidity,
from a partial removal of tumor followed by radiation therapy, or
from radiation therapy alone.
Some general guidelines for the treatment
of these tumors can be outlined. For patients with mild or nonprogressive
symptoms it may be appropriate to follow the patient with periodic
scans and examination to determine whether the lesion is growing
and to see whether the symptoms are significantly interfering with
the patient's life. The indications for surgery in younger patients
are worsening symptoms and/or growth seen on follow-up scans and
in older patients are large tumors with worsening symptoms. Radiation
therapy is used in older patients with small and medium-size tumors
with worsening symptoms and for regrowth after subtotal or radical
The operative approach is similar
to that used for tuberculum sella meningioma but with a more temporal
exposure. It may be necessary to open the medial aspect of the Sylvian
fissure to define the middle cerebral artery.
I prefer a frontal temporal craniotomy,
as have others (9, 26, 47, 48). Al-Mefty and Smith (5) describe
a cranio-orbital approach with section of the zygomatic arch and
inclusion of the supraorbital ridge in the bone flap.
The key considerations in the operation
- Intemal decompression of the tumor,
staying away from the region of the internal carotid and middle
cerebral arteries. Some soft tumors can be more easily removed
than very fin-n hard tumors.
- Identification of the distal branches
of the middle cerebral artery and following them to the tumor
capsule to determine whether it is feasible to dissect them. In
some situations arachnoid planes help in separating the tumor
from around the encased arteries.
- Identification of the optic chiasm
and following the optic nerve into the tumor.
Al-Mefty (1) has described a group
of tumors that originate from the superior and/or lateral aspect
of the anterior clinoid process. As the tumor grows the arachnoid
membrane remains intact, making microsurgical dissection from the
internal carotid artery and optic nerve possible. Brotchi and Bonnal
(9) also emphasize the importance of the arachnoid membrane in aiding
the dissection when there is arterial encasement.
In this surgical series there were
17 patients (Table 17.3). There were 13 women and four men ranging
in age from 28 to 79 years, with two over 70 years of age. In no
patient could I be absolutely sure of a total removal because of
involvement of important arteries and/or cranial nerves or the
extension of the tumor into the cavernous
sinus or orbit. In 16 patients there was a good result. One patient
had a postoperative intracerebral hemorrhage 2 weeks after surgery
and has a permanent dysphasia and hemiparesis.
|TABLE 17.3 Medial
Sphenoid Wing Meningiomas
aT, total removal
RST, radical subtotal removal
ST, subtotal removal
bGood, free of major
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
In 11 patients no radiation therapy
has been given and there has been no change in their tumor over
a period of 1-11 years (mean, 5 year) after operation. Six patients
were given radiation therapy, three immediately after operation
and three when there was evidence of recurrence. Two of the patients
with recurrence had reoperation and then radiation therapy to the
small residual tumor, and one with diffuse involvement in the orbit
and cavernous sinus was given radiation without further surgery.
Following radiation therapy five patients are stable and one has
shown slight growth over a relatively short follow-up.
Brotchi and Bonnal (9) reported total
removal in nine of 28 patients, and 21 had no or minimal sequelae.
Excellent results have been reported by Al-Mefty (1), with total
removal in 20 of 27 patients.
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