File 7: OPTIC SHEATH MENINGIOMA
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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.
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. 17.8. Optic sheath
meningioma. This 45-year-old woman had decreasing vision
in her left eye. Vvhen intracranial extension became apparent,
operation was recommended. (A and B) MRI axial
TI images (A and B) after gadolinium show the
tumor involving the left optic nerve in the orbit, with intracranial
extension (arrows). (C and D) MRI coronal TI images
after gadolinium show encasement of the left optic nerve by
the tumor (C) (arrow) and the intracranial extension
OPTIC SHEATH MENINGIOMAS
(Meningioma Management, File 7)
MRI clearly outlines the extent of
the tumor (Fig. 17.8). Angiography is not needed. Decisions regarding
treatment are difficult when the patient still has useful vision.
Generally we have observed the patients with useful vision and also
those with poor vision with the tumor confined to the orbit. The
indications for surgery have been poor vision and intracranial extension
or increasing orbital symptoms. Wiight et al. (78) have emphasized
the more aggressive nature of these tumor in younger patients and
have recommended an earlier surgical approach in that age group.
Since the prognosis for vision is
so poor, radiation therapy has been used in a few patients in whom
there is worsening but still useful vision (31, 45). The radiographic
appearance is so characteristic that a tissue diagnosis is not needed.
The surgical approach is through a
frontal-temporal craniotomy. The key considerations in the operation
- Removal of bone in the roof of the
orbit and over the optic canal.
- Exposure of the tumor by retracting
the levator and superior rectus muscles laterally.
- Division of the optic nerve at the
back of the globe.
- Opening of the dura over the inferior
frontal and anterior temporal region and division of the optic
nerve as far forward as possible to avoid injury to fibers from
the opposite side that may loop into the proximal nerve (Wilband's
- Removal of the tumor and optic nerve
from the optic canal.
- Division of the annulus of Zinn
and after removal of the tumor, which may be densely adherent
in this area, resutuiing of the annulus.
- Closure without replacement of the
|TABLE 17.6 Optic
||Temporary ptosis and
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
Fifteen patients had operations for
removal of an optic sheath meningioma usually because of intracranial
extension (Table 17.6). There were 13 females and two males ranging
in age from 16 to 65 years. All had poor or absent vision preoperatively.
All made a good recovery. The intracranial tumor was completely
removed in 14. Four patients had a small a,mount of tumor left growing
into the back of the globe. One patient had a radical subtotal removal
with a small piece of tumor left adherent to the internal carotid
artery. There has been no recurrence.
Postoperatively every patient had
ptosis and extraocular muscle paresis but this usually recovered
within a few months. There was one complication of a cerebrospinal
fluid leak from an ethmoid air cell. This was repaired by a transethmoid
One patient, a 30-year-old man, had
complete removal of an optic sheath meningioma. In less than a year
a tumor in the other optic sheath developed with beginning visual
loss. This has been treated with radiation therapy.
Good results following operation have
been reported by others (8, 45, 61). In one report of 32 patients
in whom it was thought total removal had been done, three tumors
recurred and all were described as showing an infiltrative pattern
of growth (17). Kennerdell et al. (31) reported that, of six patients
treated with radiation therapy (5400-5500 cGy), five had improvement
in visual acuity with follow-up ranging from 3 to 7 years.
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