Digital tomosynthesis enhances cervicothoracic sagittal alignment assessment: are cervicothoracic sagittal parameters correlated with the occurrence of cervical spondylotic myelopathy?

PURPOSE

To evaluate the availability of digital tomosynthesis (DTS) in assessing cervicothoracic junction sagittal alignment, and investigate the correlation between cervicothoracic sagittal parameters and the occurrence of cervical spondylotic myelopathy (CSM).

METHODS

A cohort of 160 participants-80 healthy controls (Group A) and 80 CSM patients (Group B)-underwent cervical lateral radiography and DTS imaging in our center. Sagittal parameters (occiput-C2 angle [O-C2], cervical lordosis [CL], C2-7 sagittal vertical axis [C2-7 SVA], neck tilt [NT], T1 slope [T1S], thoracic inlet angle [TIA], cervical tilt, and cranial tilt) were measured using both modalities. Inter-class correlation coefficients (ICCs) were calculated to assessed measurement reliability. Group comparisons and multivariate logistic regression analyses were performed to identify CSM-related parameters.

RESULTS

DTS demonstrated excellent reliability across all parameters (ICCs: 0.885-0.987), surpassing radiography (ICCs: 0.714-0.932; rated good-to-excellent). While O-C2, CL, C2-7 SVA, and NT showed no significant differences (P > 0.05), DTS yielded significantly larger measurements for T1S, TIA, cervical tilt, and cranial tilt (P < 0.05). Between groups, for CSM patients, DTS-derived CL, T1S, and cervical tilt were significantly smaller (P < 0.05), but C2-7 SVA and NT were significantly larger (P < 0.05). Multivariate analysis identified diminished CL (B = 0.120, OR = 1.128, P < 0.001) and lower T1S (B =-0.150, OR = 0.861, P < 0.001) as independent CSM risk factors.

CONCLUSION

DTS surpasses conventional radiography in precision for cervicothoracic sagittal evaluation. Reduced CL and diminished T1S are independently associated with CSM pathogenesis, highlighting their utility in clinical risk stratification.