Abstract
Introduction Decompression of the optic nerve within the optic canal is indicated for compressive
visual decline. The two most common approaches utilized for optic canal decompression
are a medial approach with an endoscopic endonasal approach and a lateral approach
with a craniotomy. Our study is a cadaveric anatomical study comparing the length
and circumference of the orbit decompressed via an endoscopic endonasal approach versus
a frontotemporal craniotomy.
Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans
were performed on each specimen. On each specimen, a standard frontotemporal craniotomy
with anterior clinoidectomy and superolateral orbital decompression was performed
on one side and an endoscopic endonasal approach with medial wall decompression was
performed on the contralateral side. Post-dissection CT scans were performed. An independent
radiologist provided measurements of the length (mm) and circumference (degrees) of
optic canal decompression bilaterally.
Results The mean length of optic canal decompression for open and endoscopic approach was
13 mm (range 12–15 mm) and 12.4 mm (range 10–16 mm), respectively. The mean circumference
of decompression for open and endoscopic approaches was 252.8 degrees (range 205–280
degrees) and 124.6 degrees (range 100–163 degrees), respectively.
Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length
of optic canal decompression, but the transcranial approach leads to greater circumferential
decompression. The endoscopic endonasal approach has the benefit of being minimally
invasive, though. Ultimately, the surgical approach decision should be based on the
location of the pathology and the surgeon's comfort.
Keywords
orbit - optic canal - optic canal decompression - endoscopic endonasal approach -
frontotemporal craniotomy
