Endoscopic Transorbital and Endoscopic Endonasal Approaches to Petrous Apex: A Systematic Review

Background: Endoscopic endonasal approaches (EEAs) are commonly used to address petrous apex (PA) lesions. However, they have anatomical limitations and present a risk of injury to vital neurovascular structures. To mitigate these risks and expand the corridors of endoscopic skull base surgery, transorbital approaches (TOAs) have been well-described. Methods: We conducted a PRISMA-guided systematic literature review to compare EEAs and TOAs for petrous apex pathologies. Results: Twelve full-text articles were reviewed out of 255 studies in the Medline and Embase databases, and five studies were included per set eligibility criteria. Four out of five studies comparing EEAs and TOAs for PA were cadaveric, and one was a retrospective review. The approaches compared were Endoscopic precaruncular contralateral medial transorbital (cMTO), Contralateral transmaxillary (CTM), Superior Eyelid Transorbital approach (SETOA), Transconjuctival Transorbital approach (TCTOA), and Transpetrygoid endoscopic endonasal approach (EEA). The working distance was significantly less in the cMTO approach vs EEA or CTM in two cadaveric studies (p < 0.001), and also for SETOA vs EEA in one cadaveric study (p < 0.01). The visual angle was better with cMTO (cMTO vs EEA; p < 0.001 and cMTO + EEA vs CTM + EEA; p < 0.005), assessed in two studies. There was reduced conflict between the instruments and the endoscope in cMTO vs CTM (p < 0.001) and increased surgical freedom with cMTO vs EEA (p < 0.001) in one cadaveric study. The cadaveric studies discussed the potential complications of TOAs, but the retrospective study using SETOA and TCTOA reported no complications. The extent of surgical exposure was discussed in all five studies, with the cMTO approach giving the top-down view and exposing the superomedial portion, and SETOA exposing the superolateral portion of PA. In the retrospective study, TOA provided direct surgical access superior to PA without internal carotid artery mobilization, posterior to PA using 30° and 45° lenses, and inferior to PA after tumor resection. Conclusion: The transorbital corridor offers a feasible pathway to the petrous apex with possible enhanced surgical maneuverability compared to traditional endoscopic endonasal techniques. Further prospective studies are needed to directly compare complications and resectability of this relatively new approach with classical endonasal approaches. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany