39 Transcranial Orbital Approaches

Wenya Linda Bi and Ian F. Dunn

Summary

Transcranial approaches afford circumferential access and visualization of the optic apparatus and serve an important role in the resection of mass lesions involving the optic nerve, especially those at the posterior third of the orbit, with intracranial extension, or with bilateral involvement. Transcranial approaches to the orbit may be conceived as a series of modular advancements, centered about the superior orbital rim, with stepwise expansion to the lateral orbital rim, zygoma, and frontotemporal calvarium. Selection of the operative approach is dictated by specific features of the lesion itself—location, extension outside the orbit, presumed pathology, vascular supply, and anticipated firmness are some important considerations. Additional concerns include existing neurologic symptoms and suspected neurovascular involvement, cosmetic considerations, and surgeon experience. Decompression of the anterior clinoid and optic canal are critical in preservation or restoration of vision in situations of optic nerve compression. Potential risks include postoperative periorbital swelling, temporary impairment of globe motility and extraocular movements, frontalis weakness, and enophthalmos or exophthalmos. Visual integrity is optimized with avoidance of intraoperative hypotension, rapid cerebrospinal fluid drainage, thermal injury from drilling or coagulation, and aggressive dissection around the optic apparatus.

Key words

cranio-orbito-zygomatic approach - supraorbital craniotomy - skull base surgery - optic nerve decompression - optic nerve meningioma