Axial pain after anterior cervical discectomy and fusion: risk factor analysis and imaging evaluation

Axial pain can occur as a complication following anterior cervical discectomy and fusion (ACDF), which is frequently regarded as a complication of posterior cervical surgery and is often overlooked after ACDF. However, the risk factors of postoperative axial pain (PAP) remain incompletely elucidated. This study aimed to analyze the risk factors and radiological assessment of PAP in patients undergoing ACDF. Individuals undergoing ACDF between January 2020 to March 2023 were included. Participants were categorized into two groups by PAP presence. Clinical parameters were collected, and radiographic parameters measured included pre- and postoperative C 2 ~ 7 Cobb angle, C 2 ~ 7 sagittal vertical axis, T 1 slope, intervertebral disc height, facet joint distance (FJD), and interspinous distance. Spinal cord function was evaluated using the Japanese Orthopaedic Association score. Univariate/multivariable analyses identified independent risk factors for PAP after ACDF. Diagnostic performance of postoperative C 2 ~ 7 Cobb angle change and postoperative relative FJD change was evaluated via Receiver Operating Characteristic curve analysis. Optimal cutoff values were determined using the Youden index. In ACDF patients, PAP prevalence was 15.5% in single-level surgery and 19.8% in multi-level surgery. For single-level ACDF, logistic regression analysis identified postoperative relative FJD change as a PAP risk factor (Area Under the Curve [AUC] = 0.809, optimal cutoff = 27.95%). For multi-level ACDF, postoperative C 2 ~ 7 Cobb angle change was a risk factor (AUC = 0.773, optimal cutoff = 3°). During ACDF procedures, minimizing FJD in single-level surgery and avoiding excessive C 2 ~ 7 Cobb angle correction in multi-level surgery may reduce PAP prevalence.