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.