Transorbital Transnasal Endoscopic Combined Approach to Anterior and Middle Skull Base: Laboratory Investigation

Abstract

Objectives:

Orbital approaches provide significant trajectory to the skull base and are used with different designed pathways. The aim of this study is to investigate the feasibility of a combined endoscopic transorbital and transnasal approach to the anterior and middle cranial fossa.

Methods:

Cadaveric dissection of 5 silicon-injected heads. A total of 10 bilateral transorbital approaches and 5 extended endonasal approaches were performed. Identification of the surgical landmarks, main anatomical structures, feasibility of combined approach, and reconstruction of the superior orbital defect were examined. Rod lens endoscope (with 0° and 45° lenses) and endoscopic instruments were used to complete the dissection.

Results:

The transorbital approach showed great versatility and provided the surgeon a direct route to the anterior and middle cranial fossa. Anterior/posterior ethmoid arteries, optic nerve, and superior orbital fissure were the landmarks for the superior orbital wall craniectomy. Transorbital avascular plane showed no conflict with major nerves or vessels. Large exposure area from crista galli to the third ventricle was demonstrated with significant control of different neurovascular structures. The combined transorbital transnasal approach provided considerable value in form of extent of the exposure and the free hand movement of the 2 surgeons.

Conclusions:

Combined transorbital transnasal approach demonstrates better visualization and control of the ventral skull base and can overcome the current surgical limits of a single approach. Combination of these 2 minimally invasive approaches should reduce the overall morbidity. Clinical trials are needed to evaluate the virtual applications of this approach.