Optic canal decompression: a cadaveric study of the effects of surgery.

PURPOSE: To simulate a transphenoidal medial optic canal decompression and determine the anatomic effect on the optic nerve. METHODS: A medial optic canal decompression was performed on 5 cadaveric optic canals within 12 hours of death. Two canals were decompressed under direct visualization and 3 were decompressed by a transphenoidal endoscopic approach. The optic canal was subsequently removed en bloc, beginning at the annulus of Zinn and extending to the optic chiasm. Each specimen was processed and examined grossly. Serial coronal step sections of the entire length of the intracanalicular optic nerve were assessed histologically. RESULTS: Microscopic examination of the intracanalicular portion of optic nerve revealed incision in an extraocular muscle at the annulus, incomplete bone removal, fraying of the dural sheath, incomplete dural/arachnoid release, and incision in the pia and optic nerve. CONCLUSIONS: Transphenoidal medial wall decompression of the optic nerve canal with dural sheath opening may induce physical damage to the nerve. Any hypothetical value in dural-arachnoid sheath opening must be weighed against the potential for harm to the optic nerve caused by the surgical intervention.

Echography as a useful adjunct in the diagnosis of orbital solitary fibrous tumor.

PURPOSE: To describe the echographic features of solitary fibrous tumor of the orbit. METHODS: A retrospective review of 3 patients with solitary fibrous tumor of the orbit and a literature review were performed. RESULTS: Three patients with orbital solitary fibrous tumor were studied with standardized echography and 3 other cases of orbital solitary fibrous tumor with ultrasound descriptions were identified in a literature review. Consistent echographic features of the 6 orbital solitary fibrous tumors included firmness, low to medium internal reflectivity, regular internal structure, moderate sound attenuation, and some degree of vascularity. CONCLUSIONS: Standardized echography is a useful adjunct in the evaluation of orbital solitary fibrous tumors and can help differentiate these tumors from other orbital lesions.