Surgical Treatments of C1 Fracture: Can Preoperative Dynamic Tomography Improve Surgical Outcomes?

Aim
To investigate whether preoperative dynamic computed tomography improves
surgical decision-making and radiological and clinical outcomes in patients with
unstable fractures of the atlas vertebra.

Material and Methods
A retrospective review was performed of patients with atlas fractures treated between
January 2015 and December 2023. Demographic data, fracture morphology, integrity
of the transverse atlantal ligament, and craniovertebral junction alignment were
assessed using radiography, magnetic resonance
imaging, and preoperative dynamic computed tomography in extension.The choice between isolated atlas fixation, atlas–axis fusion, and occipitocervical fusion was determined by dynamic evaluation of the C1–C2 and
craniovertebral motion segments.

Results
Thirty-eight patients met the inclusion criteria; 5 were lost to follow-up, leaving 33
patients for analysis. Eighteen patients were treated nonoperatively because their
fractures were radiologically stable on conventional imaging. Fifteen patients with
unstable fractures underwent surgery. In 4 patients with instability confined to the
atlas ring and preserved C1–C2 alignment on dynamic imaging, isolated atlas fixation
was performed. Nine patients demonstrated pathological C1–C2 motion on dynamic
computed tomography, with a mean lateral mass displacement of 9.9 millimetres and
a mean C1–C2 angular opening of 36.8 degrees; these patients underwent posterior
atlas–axis fusion. Two patients showed additional craniovertebral junction
compromise with increased basion–dens distance and underwent occipitocervical
fusion. No patient experienced perioperative neurological or vascular complications.
No pseudarthrosis or late C1–C2 instability occurred in the isolated atlas fixation
group. Complications were limited to screw malposition requiring revision, occipital
neuralgia in one atlas–axis fusion case, and one cerebrospinal fluid leak after
occipitocervical fusion.

Conclusion
Preoperative dynamic computed tomography enables physiological and quantitative
assessment of the C1–C2 and craniovertebral motion segments, allowing reliable
discrimination between isolated atlas ring instability and true atlantoaxial or
craniovertebral junction instability. Incorporating this modality into surgical planning
supports individualized selection of isolated atlas fixation, atlas–axis fusion, or
occipitocervical fusion, thereby optimizing mechanical stability while preserving
cervical motion whenever safely possible.

atlas fracture dynamic CT C1–C2 fusion transverse atlantal ligament