Focused endoscopic endonasal craniocervical junction approach for resection of retro-odontoid lesions: surgical techniques and nuances

Background: Lesions posterior to the odontoid process pose a surgical challenge. Posterolateral approaches to this region are considerably risky for the spinal cord. Transoral approaches are limited in terms of exposure and can also carry morbidity. Methods: We describe a focused endoscopic endonasal approach (EEA) for removing an osteochondroma located dorsal to the odontoid process. The surgical pearls and pitfalls using stepwise image-guided EEA cadaveric dissections are highlighted defining the importance of various craniocervical junction (CCJ) lines on imaging. Conclusion: EEA to CCJ can be offered, with lower morbidity than other approaches, even for lesions that extend posterior and caudal to the odontoid process. Radiologic predictors of exposure and intraoperative techniques to enhance endoscopic visualization are discussed.