At present, most scholars hold that the neurological symptoms are due to the thickening of the bone plate at the bottom of the skull and stenosis or occlusion of channels in which cranial nerves, spinal cord, and major blood vessels run, including the optic nerve compression caused by the optic canal
The intracranial extension has been described through the three major openings in the posterior aspect of the orbit, which include the superior orbital fissure, optic canal
and the inferior orbital fissure.
Bony dehiscence of the sphenoid sinus over the optic canal
occurs in 4%-13% of cases.
After the resection of the lateral portion of the lesser wing of the sphenoid bone, the orbital roof is removed as far medially as the optic canal
, which serves as convenient landmark and reference point during the remaining portion of the dissection.
Computed tomography performed in May 2005 (Aquillion, Toshiba; resolution 300 dpi) of the orbits revealed diffuse involvement of multiple cranial bones by fibrous dysplasia with involvement of the left orbit, nasal cavity, sinuses, and showed replacement of the left orbital roof and the lesser wing of the sphenoid by dysplastic bone with alternating areas of lucency and increased density ("pagetoid" lesion), and narrowing of the left optic canal
Orbital reconstruction is fraught with the risk of encroaching on the optic canal
and this is yet another fine example of upholding Apollo Hospital's vision of using Cutting edge technology for enhancing patient safety.
This formation separates optic canal
from the medial portion of superior orbital fissure.
If the penetration is parallel to the orbital roof, it will violate the cranium through the superior orbital fissure or optic canal
, and usually does not result in bone fracture.
During surgical procedures, the surgeon must always remember that the optic canal
and the bulge of the internal carotid artery may only be covered by a very thin and occasionally fragmented bony layer in the area of the sphenoid and that these two vital structures may not be well protected (Stammberger).
1) Prostate cancer has also been reported intracranially to involve the optic canal
and orbits, resulting in amaurosis or blindness.
Embryology of the normal optic canal
and its anomalies.
Surgical management of tuberculum sellae meningiomas: Involvement of the optic canal
and visual outcome.