The Subcranial Approach to the Anterior Skull Base

Abstract

The subcranial approach is a single-stage open procedure for patients with tumors involving the anterior skull base. It is also known as the subfrontal or the transglabellar approach. The concept of a broad subcranial approach to the entire anterior skull base was first introduced by Raveh for cases of traumatic injuries and was later adapted for surgical removal of tumors involving this anatomic region. The extent of exposure of the subcranial approach includes the frontal sinus anteriorly, the clivus posteriorly, the frontal lobe superiorly, and the paranasal sinuses inferiorly. Laterally, the boundaries of this approach are both superior orbital walls. The subcranial approach has several major advantages: (1) it affords a broad exposure of the anterior skull base from below rather than through the transfrontal route; (2) it provides excellent access to the medial orbital walls and to the sphenoethmoidal, nasal, and paranasal cavities; (3) it allows simultaneous intradural and extradural tumor removal and safe reconstruction of dural defects; (4) it does not require facial incisions; and (5) it is performed with minimal frontal lobe manipulation. Although endonasal surgery replaced some of the indications that were traditionally managed by this approach, there are still indications for subcranial resection, including tumor infiltration to the frontal sinus skin and subcutaneous tissue, mid and lateral orbital planes, palate, nasal bones, lacrimal sac, and massive dural and brain parenchyma.