Cervical Vertebral Bone Quality Score Independently Predicts Distal Junctional Kyphosis After Posterior Cervical Fusion.

BACKGROUND AND OBJECTIVE: Posterior cervical fusion is the surgery of choice when fusing long segments of the cervical spine. However, because of the limited presence of this pathology, there is a paucity of data in the literature about the postoperative complications of distal junctional kyphosis (DJK). We aimed to identify and report potential associations between the preoperative cervical vertebral bone quality (C-VBQ) score and the occurrence of DJK after posterior cervical fusion. METHODS: The authors retrospectively reviewed records of patients who underwent posterior cervical fusion at a single hospital between June 1, 2010, and May 31, 2020. Patient data were screened to include patients who were >18 years old, had baseline MRI, had baseline standing cervical X-ray, had immediate postoperative standing cervical X-ray, and had clinical and radiographic follow-ups of >1 year, including a standing cervical X-ray at least 1 year postoperatively. Univariate analysis was completed between DJK and non-DJK groups, with multivariate regression completed for relevant clinical variables. Simple linear regression was completed to analyze correlation between the C-VBQ score and total degrees of kyphosis angle change. RESULTS: Ninety-three patients were identified, of whom 19 (20.4%) had DJK and 74 (79.6%) did not. The DJK group had a significantly higher C-VBQ score than the non-DJK group (2.97 ± 0.40 vs 2.26 ± 0.46; P < .001). A significant, positive correlation was found between the C-VBQ score and the total degrees of kyphosis angle change (r 2 = 0.26; P < .001). On multivariate analysis, the C-VBQ score independently predicted DJK (odds ratio, 1.46; 95% CI, 1.27-1.67; P < .001). CONCLUSION: We found that the C-VBQ score was an independent predictive factor of DJK after posterior cervical fusion.

Comparative Analysis of the 3 Cervical Vertebral Bone Quality (C-VBQ) Score Methodologies and Their Correlations to the Lumbar Vertebral Bone Quality (VBQ) Score.

OBJECTIVE: Common complications after spinal fusion, such as pseudoarthrosis, cage subsidence, or instrumentation failure, are affected by patients' bone quality. The cervical-vertebral bone quality (C-VBQ) score, a magnetic resonance imaging (MRI)-based adaption of the lumbar vertebral bone quality (VBQ) score, was developed by 3 separate research groups simultaneously to evaluate bone quality in cervical spinal fusion patients. We present the first analysis comparing these scoring methods to the well-validated VBQ score. METHODS: A retrospective analysis of data for consecutive patients who underwent spine surgery at a single institution was completed. The VBQ score was calculated using the Ehresman et al. METHOD: The C-VBQ scores, named according to placement of the region of interest within the cerebral spinal fluid, were calculated separately using the methods of Soliman et al. (C2-VBQ), Razzouk et al. (C5-VBQ), and Huang et al. (T1-VBQ). Linear regression models were utilized to evaluate correlations to the VBQ score. RESULTS: A total of 105 patients were identified (mean age, 57.0 ± 11.9 years; women, 50.5%). Mean scores were C2-VBQ, 2.37 ± 0.55; C5-VBQ, 2.36 ± 0.61; and T1-VBQ, 2.64 ± 0.68. The C-VBQ scores for the C2 level were significantly higher than those for the C3-C6 levels (3.18 ± 0.96 vs. 2.63 ± 0.77, P < 0.001), whereas the C7 level was found to have significantly lower C-VBQ scores (2.42 ± 0.78 vs. 2.63 ± 0.77, P = 0.04). The C2-VBQ (r = 0.63) score had the strongest correlation to the VBQ score, compared to C5-VBQ (r = 0.41) and T1-VBQ (r = 0.43) (P < 0.001). CONCLUSIONS: This study demonstrates that the C2-VBQ had the strongest correlation to the lumbar VBQ score among all C-VBQ scores.