MICROSCOPIC AND ENDOSCOPIC EXTRACRANIAL APPROACHES TO THE CAVERNOUS SINUS: ANATOMIC STUDY

OBJECTIVE In the past 2 decades, various extracranial approaches to the cavernous sinus (CS), using either microscopic or endoscopic techniques, have been described. The aim of this study was to describe the distinctive anatomic features of these approaches and compare their efficacy in exposing the sella and parasellar areas. METHODS Ten adult cadaver heads with red latex injected in the arterial system were used. Five different approaches were performed: 1) endonasal microscopic transsphenoidal approach; 2) sublabial microscopic transsphenoidal approach, including its variation described by Fraioli et al. (12); 3) transmaxillary microscopic approach; 4) paraseptal endoscopic transsphenoidal approach; and 5) transethmoid-pterygoid-sphenoidal endoscopic approach. The CS exposition was evaluated for each approach and a grading system, which considers surgical maneuverability as well as visualization, was used. RESULTS The medial CS compartment is well exposed with all endoscopic and microscopic transsphenoidal approaches, but it is insufficiently exposed with the transmaxillary approach. The variation to the sublabial microscopic approach suggested by Fraioli et al. allows its widest microsurgical exposure. The lateral compartment is well visualized with the transmaxillary microscopic and the endoscopic approaches. The major anatomic structures that can limit exposure of the CS lateral compartment are the posterior ethmoid and medial pterygoid process. CONCLUSION The sublabial transsphenoidal microscopic approach, with its variations, allows the most versatile extracranial microscopic exposure of the sella and CS. The paraseptal, binostril endoscopic approach allows a very good exposure of the CS; the transethmoid-pterygoid-sphenoidal endoscopic approach achieves the best maneuverability in the lateral compartment of the CS.