Transorbital Approach to the Cavernous Sinus After an Exenteration.

BACKGROUND AND OBJECTIVES

To describe a novel technique of transorbital access to the lateral wall of the cavernous sinus (CS) after exenteration.

METHODS

Cadaveric dissection study. Seven heads (13 orbits) were dissected after total orbital exenteration. The technique was centered on creation of an osteotomy within the greater wing of sphenoid, bordered by the superior and inferior orbital fissures to access the middle cranial fossa. V2 within the foramen rotundum was used as a guide to enter the interdural plane of the lateral CS wall. Results were expressed as the mean value ±1 SD.

RESULTS

The lateral CS wall was precisely visualized with identification of cranial nerves III to V2 back to the anterior portion of the Gasserian ganglion. To enable this level of exposure, the osteotomy created within the greater wing of sphenoid was a triangular window with a height of 12.7 ± 1.5 mm (range 10.0-15.0 mm), bordered superiorly by the superior orbital fissure to a linear dimension of 12.8 ± 2.5 mm (range 8.0-18.0 mm), and inferiorly by the inferior orbital fissure to an extent of 12.1 ± 3.9 mm (range 0.9-15.0 mm). The distances from the orbital apex to the intracavernous cranial nerves V1 and V2, and V3 within the foramen ovale were 22.9 ± 3.6 mm (range 17.0-31.0 mm), 25.2 ± 5.0 mm (range 17.5-36.0 mm), and 27.8 ± 5.9 mm (range 18.0-41.0 mm), respectively. The distance between the orbital apex and anterior Gasserian ganglion approximated the maximum surgical corridor achieved with this technique, which was 31.8 ± 4.8 mm (range 26.0-44.0 mm).

CONCLUSION

The transorbital approach to the lateral CS wall is a feasible corridor of access after exenteration. It provides an alternative interdural pathway, thereby obviating the need for additional transcranial or endonasal access routes. Such a technique is in its infancy and surgical series are required to verify it in the clinical setting.