Combined Approaches to Complex Skull Base Tumors

Abstract

The classic open approaches to the skull base include the subcranial/subfrontal, orbitozygomatic, pterional, transpetrosal, middle fossa, retrosigmoid, and far lateral approaches. These approaches cover the anterior, middle, and posterior skull base from above. Although these approaches permit tumor resection in most cases, there are still situations in which the inferior, lateral, or posterior aspects of the tumor are not adequately exposed by an individual approach. These include malignant or benign neoplasms with extensions to the maxillary antrum and palate caudally; to the cavernous sinus posteriorly; to the orbital apex, pterygopalatine fossa, or the infratemporal fossa laterally; or involvement of the nasopharynx and inferior aspect of the clivus inferoposteriorly. Such cases require a combination of several approaches in a single-stage procedure. In these combined approaches, a second approach, such as midfacial degloving or an orbitozygomatic, transfacial, endoscopic, or transorbital approach, is added to enable proper exposure and tumor extirpation. These combined approaches require additional incisions and osteotomies, depending on the type and extent of the tumor. This chapter describes combinations of the anterior and lateral approach frequently used for extirpation of complex tumors extending out from the anterior skull base.