Optic canal decompression: a cadaveric study of the effects of surgery.
OBJECTIVE
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.
Onofrey
Cassandra B
CB
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
Tse
David T
DT
Johnson
Thomas E
TE
Neff
Ann G
AG
Dubovy
Sander
S
Buck
Billy E
BE
Casiano
Roy
R
D019299:Decompression, Surgical / Q000009:adverse effects*; D006801:Humans; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects*; D009900:Optic Nerve / Q000473:pathology*; D020221:Optic Nerve Injuries / Q000175:diagnosis / Q000209:etiology*; D009915:Orbit / Q000601:surgery*; D013101:Sphenoid Sinus