An extracranial microsurgical approach to the optic nerve.

Lesions affecting the canalicular portion of the optic nerve have classically been addressed with intracranial surgical techniques. This article introduces a microsurgical extracranial approach to the optic canal that can be readily adapted by the neurosurgical-rhinologic team familiar with transsphenoidal hypophysectomy. The approach became clinically feasible with the advent of coaxial illumination, magnification, and special microinstrumentation. The technique is described in detail, potential and actual clinical applications are further outlined, and the advantages and disadvantages of the approach are discussed. Future adaptability of this technique to unusual clinical situations such as ophthalmic artery aneurysms and carotid-cavernous sinus fistulas may be possible but will first require careful laboratory study.