Prognostic Factors in Craniocervical Realignment for Crainovertebral Junction Kyphosis With Negative Cervical Imbalance: A Comprehensive Study.

Objective: To elucidate the clinical outcomes of craniocervical realignment surgery in patients with craniovertebral junction (CVJ) kyphosis accompanied by negative sagittal imbalance, and to identify radiological predictors associated with favorable outcomes.

Methods: A retrospective analysis was performed on 28 patients who underwent craniocervical realignment between 2014 and 2022 for CVJ kyphosis with accompanying negative sagittal imbalance. Clinical outcomes were evaluated using the Neck Disability Index (NDI), visual analogue scale for neck pain, and the Japanese Orthopaedic Association (JOA) score. Radiographic parameters included the C0-2 angle and the C2-7 sagittal vertical axis (SVA). Favorable outcomes were defined as an improvement of more than 20 points in the NDI and a JOA recovery rate exceeding 50%. Multiple linear regression and receiver operating characteristic (ROC) curve analyses were conducted to identify independent predictors and to determine optimal threshold values.

Results: Significant improvements in both clinical outcomes and radiographic alignment were observed in association with craniocervical realignment surgery. Patients who achieved favorable outcomes exhibited greater postoperative changes in the C0-2 angle and the C2-7 SVA. Multivariate analysis identified changesm in the C0-2 angle (p=0.019) and C2-7 SVA (p=0.010) as independent predictors of NDI improvement, while age (p=0.033) and C2-7 SVA change (p=0.037) were independently associated with the JOA recovery rate. ROC curve analysis determined optimal cutoff values of ≥10.65° for C0-2 angle change and ≥19.2 mm for C2-7 SVA change, with corresponding area under the curve values of 0.872 and 0.802, respectively.

Conclusion: Craniocervical realignment appears to be a viable surgical option for patients with CVJ kyphosis and negative sagittal imbalance. Postoperative changes in C0-2 angle and C2-7 SVA were found to be associated with favorable clinical and functional outcomes, suggesting their potential role as prognostic factors.