Objective: The tumors involving the orbit and Meckel’s cave remain extremely challenging because
of the surrounding complex neurovascular structures and which involve the deep orbit,
floor of the frontal bone and lesser and greater wing of sphenoid bone. We introduce
a new minimal-access technique using the endoscopic transorbital approach (eTOA) to
cranioorbital lesions, Meckel’s cave and the middle cranial fossa lesions and review
the surgical tips and pitfalls of this approach.
Methods: Between September 2016 and September 2019, we performed eTOA in 45 patients with
tumors involving the sphenoorbital areas, Meckel’s cave lesions and middle cranial
fossa or petrous apex lesions. The pathologies included schwannoma (14), meningioma
(20), dermoid (2), trauma (2), and other malignancies. We evaluated the clinical outcome,
associated morbidities, and limitations of this novel surgical technique.
Results: Among 45 patients, 32 (71.1%) underwent gross total or near total resection of tumor.
Four patients underwent extended eTOA (with lateral orbital rim osteotomy). For meningioma,
GTR/NTR rate was 35% but patients with schwannoma had 92% of GTR/NTR rate. Of them,
14 patients (46.7%) had preoperative proptosis on the ipsilateral side and all of
14 patients had improvement in exophthalmos. Among 10 patients, 6 were with preoperative
optic neuropathy had postoperative improvement. Drilling of the trapezoid sphenoid
floor, a middle fossa “peeling” technique, and full visualization of the Meckel’s
cave were applied to access the lesions. There was no postoperative cerebrospinal
fluid leak and postoperative optic neuropathy. To access the lateral and inferior
margin of the tumor, the emphasis should be placed on the importance of adequately
removing the greater sphenoidal wing and lateral orbital rim, when needed. However,
eTOA may still have a limitation in approaching posterior fossa lesions and infratemporal
fossa because of the limited working space.
Conclusion: The eTOA affords a direct route to access orbit, Meckel’s cave and the middle cranial
fossa lesions. With experience, this novel approach will be successfully applied to
selected skull base lesions.
