Three-step anterolateral approaches to the skull base

Abstract

Adequate intraoperative exposure of the brain is paramount to prevent unnecessary retraction of the brain parenchyma. Lesions in the anterior skull base, the middle fossa and even the upper part of the posterior fossa can be managed anterolaterally through the pterional approach, the orbitozygomatic approach and the transzygomatic approach. Although commonly discussed on a separate basis, these three procedures are here considered to belong in the same spectrum, which includes one, two or three step procedures depending on the case and the level of exposure required. Ten hemispheres were used to describe the surgical technique applied in a three-step anterolateral approach. The pterional approach provides adequate access to the frontal base and the Sylvian fissure, the circle of Willis and the optic nerves. Where access to the temporal base is needed, improved exposure can be afforded by sectioning the zygomatic arch and lowering the masseter muscle. The lateral orbital wall is sectioned to improve the vertical angle of approach and facilitate access to hypothalamic and posterior fossa lesions. The combination of three approaches into one procedure introduces a new perspective on this technique, one which makes them easier to understand and shows how craniotomy may be modified for optimal exposure, even while conducting the surgery.