Contralateral Transmaxillary Corridor Used in Endoscopic Endonasal Approach for Resecting Adenoma Invading the Retrocarotid Area of the Cavernous Sinus and Beyond: Surgical Anatomy, Patient Selection Algorithm, and Illustrative Cases

BACKGROUND AND OBJECTIVES: The cavernous internal carotid artery (cICA) and its branches can make it challenging to approach the lateral portion of the retrocarotid area of the cavernous sinus (RcACS) and surrounding areas during the endoscopic endonasal approach (EEA). This can sometimes require more invasive transcranial approaches, causing a higher risk of complications. We sought to explore the feasibility of adding a contralateral transmaxillary (CTM) corridor to improve access to the RcACS during EEA. METHODS: We performed EEA and CTM extensions on 6 cadavers (12 sides) using image guidance. The depth of the surgical corridor, the surgical exposure, the angle of attack, and the trajectory to the anterior genu of the cICA were measured. Two illustrative clinical cases are presented. RESULTS: Compared with the contralateral transnasal approach, the CTM corridor provided a 10.76 (5.32)-mm shorter distance (P < .001), 36.23% (20.70%) larger surgical exposure (P < .001), and a 24.6° (3.4°) more parallel trajectory to the anterior genu of the cICA (P < .001). The mean angle of the lateral nasal wall line and the middle eye line was equal to the mean angle of the contralateral transnasal (P = .075) and CTM (P = .262) approaches, respectively. The CTM corridor allowed us to achieve near-total resection of the RcACS and beyond in 2 invasive adenomas with significant lateral extension. CONCLUSION: The CTM corridor is a feasible addition to standard EEA to access the RcACS and beyond, providing a more medial-to-lateral trajectory and improved access. The middle eye line can be used as a reference to help select patients for this approach.