Atlanto-occipital assimilation: the role of ex-, basi-, and suboccipital bones in the physiopathology of type I basilar invagination. Patient series.

Key Points

• Investigate the role of different cranial bones in atlanto-occipital assimilation related to type I basilar invagination.
• Conducted a CT analysis with multiplanar and 3D reconstructions of cranial anatomy.
• Evaluated the frequency and consistency of assimilation sites in patients with type I basilar invagination.
• Assessed the involvement of exoccipital-atlas and other cranial connections.
• The condyle-mass complex was found to be the most consistent site of assimilation.
• Variability was noted in anterior and posterior arch fusions.
• Nonsegmentation of the exoccipital-atlas lateral mass was identified as a common feature in cases.