Persistence of the midline septum of the odontoid process: anatomical and radiological study.

BACKGROUND

During our screening of the computed tomography (CT) images of the craniocervical junction, we noticed that the odontoid process occasionally contains a highly ossified region in the midline consistent with a bony septum. Given its potential significance, this study aimed to investigate the highly ossified region in the midline of the odontoid process and to discuss its clinical relevance.

METHODS

Eleven C2 vertebrae from formalin-embalmed cadaveric heads were assigned to micro-CT examination. When the midline septum was confirmed, gross anatomical and histological observations were performed. Another 20 dry adult C2 vertebrae were randomly chosen, and the midline septum was investigated using gross anatomical and histological observations.

RESULTS

Overall prevalence of the midline septum was 22.6% (7/31) (36.7% with cadaveric C2 using micro-CT and 15% in dry C2). The midline septa were found within the anterior two-thirds in the axial view and superior two-thirds in the coronal view. The midline septum in each sample varied in its shape.

CONCLUSIONS

To our knowledge, this is the first study of the persistence of the midline septum of the odontoid process. We found the overall prevalence of this septum was 22.6%. All of the midline septa were found within the anterior two-thirds in the axial view and superior two-thirds in the coronal view. Future clinical studies are necessary to further explore its potential biomechanical and surgical significance, particularly in influencing odontoid fracture patterns.