Abstract
Background
Skull base surgeries have increasingly adopted minimally invasive endoscopic transnasal
approaches; however, limitations such as restricted accessibility to lesions located
lateral to the optic nerve and internal carotid artery have led to exploring alternative
routes like the orbit for accessing the middle cranial fossae. This study investigates
transorbital endoscopic approaches in cadavers, focusing on the middle cranial fossa's
anatomy and evaluating the potential and challenges of exposing the middle skull base
and petrous apex.
Objective
To assess the surgical anatomy and feasibility of anterior petrosectomy via a transorbital
endoscopic approach, provide essential morphometric data, and evaluate associated
morbidity through a systematic literature review.
Methods
Using a 0-degree Karl Storz Endoscope 10 sides of five cryopreserved cadavers were
dissected through a lateral retrocanthal incision. Step-by-step photographs of anterior
petrosectomy through the endoscopic transorbital route are taken, and evaluation of
access to middle fossa triangles is performed. A systematic PubMed review analyzed
47 studies (in vivo and anatomical dissections) regarding the transorbital approach's
indications, techniques, and complications.
Results
In cadavers with a 50-cm head circumference, the median distances from the conjunctival
incision to the superior orbital fissure (SOF) and inferior orbital fissure (IOF)
lateral borders were 1.8 and 1.9 cm, respectively. The median length of the petrous
bone drilled was 2.0 cm. Additional measurements of intracranial landmarks were recorded.
Conclusion
The study confirmed the feasibility of using a transorbital endoscope to explore the
middle cranial fossa base through a lateral retrocanthal incision, offering improved
visualization. However, caution is necessary due to the proximity of intra-orbital
structures.
Keywords
endoscopic - transorbital - Kawase's triangle - petrous apex - cavernous sinus
