Radiological Evaluation of Craniocervical Region in Patients with Basilar Invagination.

STUDY DESIGN

A retrospective analysis of collected data.

OBJECTIVE

Our study aims to present the morphology of cranial-cervical spinal canal in basilar invagination (BI) patients.

SUMMARY OF BACKGROUND DATA

BI is characterized by protrusion of the odontoid process into the foramen magnum (C0), leading to compression of the cervicomedullary junction. However, no study has ever clarified the anatomical diameters of spinal canal in patients with BI.

METHODS

The study retrospectively examined computed tomography (CT)-based anatomical characteristics in a cohort of 84 patients with and without BI. We measured the anteroposterior diameter (APD) and transversal diameter (TVD) of spinal canal from C0 to C4, together with the area of vertebral canal (Area). Independent samples t test was used for statistical analysis.

RESULTS

The APD in the BI group was shorter than the control group from C0 to C2 (C0: 27.98 vs. 35.11 mm, P < 0.001; C1: 11.87 vs. 16.91 mm, P < 0.001; C2: 12.91 vs. 14.84 mm, P < 0.001), but it became longer from C3 to C4. The TVD of the BI group was significantly wider from C0 to C3 (C0: 30.59 vs. 28.54 mm, P < 0.001; C1: 31.31 vs. 25.98 mm, P < 0.001; C2: 21.56 vs. 20.40 mm, P = 0.01; C3: 22.45 vs. 21.23 mm, P = 0.013), and it had no significance at C4. The Area showed no difference between the two groups from C1 to C2, but it turned larger at C3 and C4 in BI patients.

CONCLUSION

BI patients may have shorter APD from C0 to C2, which could be the leading cause of neurological compression, necessitating decompression on sagittal plane. Below the pathological levels, BI patients have larger spinal canal than general population.

LEVEL OF EVIDENCE