ABSTRACT
BACKGROUND: Expanded endonasal endoscopic techniques allow us to treat several pathologies related to the odontoid process and craniocervical junction. Cases such as giant basilar invagination represent a surgical challenge. METHODS: The authors provide technical nuances and describe how to complete an endoscopic endonasal odontoidectomy and release the craniocervical junction with the aim of restoring a correct sagittal balance in cases with giant basilar invagination. The study of cadaveric specimens adds clarifying dissections. CONCLUSIONS: Endonasal endoscopic odontoidectomy and craniocervical junction joint release allow the treatment of irreducible basilar invagination and restoration of better sagittal balance before posterior cervical occipitocervical fusion.