Sphenoethmoid approach to the optic nerve.

Five percent of all head injuries affect some portion of the visual system, and the most common locus of injury is the canalicular segment of the optic nerve. The classic surgical approach to this area is via the transfrontal craniotomy, although the Japanese have utilized an external ethmoidal technique to provide limited extracranial access to the optic canal. Harvey Cushing utilized the transsphenoidal hypophysectomy principally for pituitary tumors causing visual deficits. This paper presents a variation of the transsphenoidal hypophysectomy technique which will allow exposure of the optic nerve from the orbital apex to the optic chiasm through the use of microsurgical instrumentation. A detailed step-wise description of the surgical methodology is presented, along with drawings to define the approach fully. Four case reports and representative pre and postoperative radiographs illustrate the actual approach in the clinical setting.