Abstract
Objective The aim of this anatomic study is to describe a fully endoscopic lateral orbitotomy
extradural approach to the cavernous sinus, posterior, and infratemporal fossae.
Material and Methods Three prefixed latex-injected head specimens (six orbital exposures) were used in
the study. Before and after dissection, a computed tomography scan was performed on
each cadaver head and a neuronavigation system was used to guide the approach. The
extent of bone removal and the area of exposure of the targeted corridor were evaluated
with the aid of OsiriX software (Pixmeo, Bernex, Switzerland).
Results The lateral orbital approach offers four main endoscopic extradural routes: the anteromedial,
posteromedial, posterior, and inferior. The anteromedial route allows a direct route
to the optic canal by removal of the anterior clinoid process, whereas the posteromedial
route allows for exposure of the lateral wall of the cavernous sinus. The posterior
route is targeted to Meckel's cave and provides access to the posterior cranial fossa
by exposure and drilling of the petrous apex, whereas the inferior route gives access
to the pterygopalatine and infratemporal fossae by drilling the floor of the middle
cranial fossa and the bone between the second and third branches of the trigeminal
nerve.
Conclusion The lateral orbitotomy endoscopic approach provides direct access to the cavernous
sinus, posterior, and infratemporal fossae. Advantages of the approach include a favorable
angle of attack, minimal brain retraction, and the possibility of dissection within
the two dural layers of the cavernous sinus without entering its neurovascular compartment.
Keywords
lateral orbital approach - endoscopic surgery - skull base surgery - anatomy
