Lateral transorbital neuroendoscopic approach to the lateral cavernous sinus

Abstract

Objective To design and assess the quality of a novel lateral retrocanthal endoscopic approach to the lateral cavernous sinus. Design Computer modeling software was used to optimize the geometry of the surgical pathway, which was confirmed on cadaver specimens. We calculated trajectories and surgically accessible areas to the middle fossa while applying a constraint on the amount of soft tissue retraction. Setting Virtual computer model to simulate the surgical approach and cadaver laboratory. Participants The authors. Main Outcome Measures Adequate surgical access to the lateral cavernous sinus and adjacent regions as determined by operations on the cadaver specimens. Additionally, geometric limitations were imposed as determined by the model so that retraction on soft tissue structures was maintained at a clinically safe distance. Results Our calculations revealed adequate access to the lateral cavernous sinus, Meckel cave, orbital apex, and middle fossa floor. Cadaveric testing revealed sufficient access to these areas using <10 mm of orbital retraction. Conclusions Our study validates not only the use of computer simulation to plan operative approaches but the feasibility of the lateral retrocanthal approach to the lateral cavernous sinus.

Keywords: cavernous sinus; endoscopic; pituitary; transnasal; transorbital; transsphenoidal.

Fig. 1

Schematic showing the entry portal to the surgical pathway. The white line represents the entrance to the surgical corridor, bounded laterally by the orbital rim and medially by a malleable retractor retracting the orbital contents. The ipsilateral cavernous sinus, internal carotid artery, and segments of the optic nerve and chiasm are shown in blue, red, and yellow.

Fig. 2

Defining the volume and dimensions of the surgical corridor. (A) Superior view showing the six vertices selected as boundaries to reach the target location, which is a polygon at the lateral cavernous sinus oriented in the sagittal plane. (B) Three-dimensional rendering of surgical corridor by vertices in MATLAB from the same viewing angle. The red lines represent the entrance window bounded by the orbital rim and the retracted orbital contents. The yellow rectangle is the target location at the lateral cavernous sinus. The blue triangles indicate the intersection of the surgical volume with the greater wing of the sphenoid.

Fig. 3

(A) Anatomy of the right orbit, exenterated. SOF, superior optic fissure; IOF, inferior optic fissure; ION, infraorbital nerve; Z, zygomatic arterial branch; OR, orbital rim; LP, lamina papyracea. The area in green approximates the region of bone to be removed in the greater wing of the sphenoid. (B) Creating the craniotomy and exposing the dura in a right orbit.

Fig. 4

Surgical navigation demonstrating an instrument accessing the lateral cavernous sinus through the lateral retrocanthal corridor approach. Note that with this approach there is minimal compression of the orbital contents. Only the anterior half of the orbit is subject to compression forces due to the location of the craniotomy greater wing of the sphenoid.

Fig. 5

Right-sided transorbital (lateral retrocanthal corridor [LRC]) endoscopic photograph through craniotomy in greater wing of sphenoid to visualize lateral cavernous sinus. TO, instrument through LRC approach portal; V1 and V2, branches of trigeminal nerve; C, cavernous sinus; TN arrow points to instrument inserted transnasally (marked by asterisk), placed lateral to the internal carotid artery into the cavernous sinus; D, dura.

Fig. 6

Transcranial photograph of the lateral cavernous sinus and cranial nerves III, IV, V1, V2, V3, and VI. The internal carotid artery (ICA) and the dura (D) of the middle cranial fossa are labeled.