 Clinical Features
Patients usually present with unilateral visual loss. Decisions regarding treatment are difficult when the patient still has useful vision. Generally we have followed 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. Because the prognosis for vision is so poor, radiation therapy has been used in a few patients in whom there was worsening but still useful vision. The radiologic appearance is so characteristic but a tissue diagnosis must be done. Surgical Management The surgical approach is through a frontotemporal craniotomy. The initial exposure is extradural. Bone is removed from the roof of the orbit and over the optic canal. Exposure of the tumor in the orbit is done by retracting the levator and superior rectus muscles laterally. The optic nerve is divided at the back of the globe. Intracranial exploration is then done. The optic nerve is divided as far forward as possible to avoid injury to fibers from the opposite side that may loop into the proximal nerve (Wilbrand's knee). The tumor and optic nerve are then elevated out of the optic canal. The resection is completed by dividing the annulus of Zinn. After removal of the tumor, which may be densely adherent in this area. the annulus is re sutured. The orbital roof does not need to be replaced Results Postoperatively every patient has ptosis and extraocular muscle paresis but this usually recovered within a few months. There was a complication of a CSF leak from an ethmoid air cell. This was repaired through a transethmoid approach. Good results following operation have been reported by others. Kennerdell et al. reported that of six patients treated with radiation therapy (5400 to 5500 cGy). five had improvement in visual acuity with follow-up ranging from 3 to 7 years.
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28-November-2013
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