Lateral Transorbital Neuroendoscopic Approach for Intraconal Meningioma of the Orbital Apex: Technical Nuances and Literature Review

Abstract Background Surgical approaches to orbital apex lesions involve the medial and lateral corridors. The transorbital neuroendoscopic (TONE) approach has been recently proposed as an elegant, bone-sparing, and minimally invasive alternative for tumors of the lateral orbital compartment. However, its effectiveness over the standard lateral orbitotomy approach still needs to be confirmed. The aim of this article is to describe the key technical aspects of the lateral trans-eyebrow TONE approach and to review the relevant literature on the surgical management of ectopic orbital intraconal meningiomas. Case Description The TONE approach was used in a 63-year-old man diagnosed with a left ectopic intraconal meningioma of the orbital apex involving the lateral compartment. The TONE approach involves performing a lateral 3-cm eyebrow skin incision. A subperiosteal dissection of the periorbita permits an intermittent medialization of the eyeball and extracapsular access to the orbital apex region. A lateral periorbital incision under full endoscopic view allows early access to two different intermuscular corridors that do not require mechanical retraction of the oculomotor muscles. The literature includes reports of 23 cases of intraconal meningiomas, which are usually benign, although the meningothelial variant is associated with a higher recurrence rate. Conclusions In our limited experience, the lateral TONE approach proved to be an effective, feasible, versatile, and minimally invasive promising alternative to be taken into account for orbital apex meningiomas involving the lateral compartment. Its technical strengths include an increased illumination and magnification of the surgical field and an unparalleled lateral view of the orbital apex.