Minimally Invasive Approaches to the Lateral Cavernous Sinus and Meckel's Cave: Comparison of Transorbital and Subtemporal Endoscopic Techniques

Background: Surgical access to the cavernous sinus and Meckel’s cave is always challenging. Endoscopic endonasal minimally invasive approaches to the medial cavernous sinus and Meckel’s cave have been very well stablished. In recent years, minimally invasive approaches to the lateral cavernous sinus have been proposed. The aim of this study is to compare different endoscopic approaches to the lateral cavernous sinus and Meckel’s cave through transorbital and subtemporal routes and describe the techniques in details.

Methods: Five cadaveric specimens (ten sides) were dissected in an anatomical laboratory. Anterior subtemporal keyhole (2 cm × 2cm) (Fig. 1) and lateral transorbital approaches (Fig. 2) were performed step-by-step to reach the cavernous sinus and Meckel’s cave. Five surgical targets were defined: (1) the superior portion of the ophthalmic nerve at the level of the superior orbital fissure; (2) the lateral portion of the maxillary nerve at the level of the foramen rotundum; (3) the lateral portion of the mandibular nerve at the level of the foramen ovale. (4) the anterior point in the proximal part of the Gasserian ganglion; and (5) the proximal portion of the greater superficial petrosal nerve. Under image guidance, horizontal and vertical angles of attack and surgical freedom for instrument manipulation were measured. After that, the zygomatic arch and the lateral orbital rim were removed and the measurements were taken again.

Results: The surgical freedom and the angles of attack were statistically different among the groups. The surgical freedom and the horizontal angles of attack have specially increased in the transorbital approach after the removal of the lateral orbital rim. Less retraction of the dura mater was done through the transorbital approaches to reach the targets.

Conclusions: Although conventional craniotomies are still the first option for the majority of the cavernous sinus and Meckel’s cave lesions, endoscopic minimally invasive approaches are already a viable and safe option for selected cases. Transorbital approaches reach the structures with less retraction of the dura mater and the addition of the lateral orbital rim removal increases the surgical freedom and angles of attack.