50 - Endoscopic Endonasal Approaches to the Skull Base and Paranasal Sinuses

Abstract

Rod-lens endoscopes provide improved light delivery and visualization through small corridors. Advances in endoscopic instrumentation have facilitated the application of these tools in endonasal approaches. Using endoscopic techniques, the median anterior, middle, and posterior fossae are accessible through an expanded endonasal approach. The objective of this chapter is to describe the endoscopic endonasal approaches to the skull base in the sagittal and coronal planes along with their indications and potential complications. The approaches in the sagittal plane can be divided from rostral to caudal into transfrontal, transcribriform, transplanum, transtuberculum, transsellar, transclival, and transodontoid approaches. Those in the coronal plane can be divided into the supraorbital, transorbital, and transpterygoid approaches. In turn, the transpterygoid approaches can be divided into five anatomic zones, namely the petrous apex, petroclival junction, quadrangular space, superior lateral cavernous sinus, and infratemporal fossa. The major potential complications include injury to the internal carotid artery, cerebrospinal fluid leak, and meningitis. Postoperative sinonasal crusting is a common temporary sequela and is directly related to the extent of mucosal damage and denuded bone.