Vertebral Bone Quality Score Independently Predicts Proximal Junctional Kyphosis and/or Failure After Adult Spinal Deformity Surgery

Abstract

BACKGROUND:Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) can be catastrophic complications associated with adult spinal deformity (ASD) surgery. These complications are markedly influenced by osteoporosis, leading to additional vertebral fracture and pedicle screw loosening. The MRI-based vertebral bone quality score (VBQ) is a newly developed tool that can be used to assess bone quality.OBJECTIVE:To investigate the utility of the VBQ score in predicting PJK and/or PJF (PJF/PJK) after ASD correction.METHODS:We conducted a retrospective chart review to identify patients age ≥50 years who had received ASD surgery of 5 or more thoracolumbar levels. Demographic, spinopelvic parameters, and procedure-related variables were collected. Each patient's VBQ score was calculated using preoperative T1-weighted MRI. Univariate analysis and multivariate logistic regression were performed to determine potential risk factors of PJK/PJF. Receiver operating characteristic analysis and area-under-the-curve values were generated for prediction of PJK/PJF.RESULTS:A total of 116 patients were included (mean age, 64.1 ± 6.8 years). Among them, 34 patients (29.3%) developed PJK/PJF. Mean VBQ scores were 3.13 ± 0.46 for patients with PJK/PJF and 2.46 ± 0.49 for patients without, which was significantly different between the 2 groups (P < .001). On multivariate analysis, VBQ score was the only significant predictor of PJK/PJF (odds ratio = 1.745, 95% CI = 1.558-1.953, P < .001), with a predictive accuracy of 94.3%.CONCLUSION:In patients undergoing ASD correction, higher VBQ was independently associated with PJK/PJF occurrence. Measurement of VBQ score on preoperative MRI may be a useful adjunct to ASD surgery planning.

Bone Quality in Spinal Surgery: Evaluation, Implications, and Treatments

“…For example, Wang et al 27 demonstrated that higher VBQ scores were significantly associated with PJK risk after surgery for adolescent idiopathic scoliosis. These findings were then replicated in the adult spinal deformity population by Kuo et al 28 VBQ has also been demonstrated to be associated with pedicle screw loosening. Li et al 29 demonstrated a 4-fold increase in the rate of pedicle screw loosening in patients with high VBQ scores.…”

MRI Vertebral Bone Quality Correlates With Interbody Cage Subsidence After Anterior Cervical Discectomy and Fusion

“…In one of these studies, a VBQ score threshold of 3.05 was found to be optimal for predicting pedicle screw loosing, with a sensitivity of 65.5% and a specificity of 71.3% 27 . Another study found that the VBQ score independently predicts proximal junction kyphosis and/or failure after adult spinal deformity surgery 29 …”

“…27 Another study found that the VBQ score independently predicts proximal junction kyphosis and/or failure after adult spinal deformity surgery. 29 Another potential use of VBQ-based bone quality analysis is predicting rates of pseudoarthrosis. There is currently no literature that describes using VBQ for this purpose, indicating a potential future direction to explore.…”

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

“…This score was later used by Soliman et al, 10 who found that the VBQ score was an independent predictor of cage subsidence after transforaminal lumbar interbody fusion. Subsequently, Kuo et al 25 found that the VBQ score independently predicted proximal junctional kyphosis when studying a thoracolumbar population. These successes in the lumbar spine led to the eventual adaptation of the VBQ score for the cervical spine in which the C-VBQ score was developed by Soliman et al 12 and was found to be an independent predictor of cage subsidence after ACDF procedures.…”

“…Although this was not the aim of this study, previous publications have demonstrated a significant relationship between the VBQ score and both imaging modalities. 12,25,27 Finally, no patients in the DJK cohort experienced compression fractures or instrumentation failure, which limits the ability to identify and analyze the causes of DJK within this cohort. Future prospective studies that are larger in scale should be completed to confirm the results of this study and investigate the correlation of DJK with patientreported outcome measurements and the incidence for the various causes of DJK to highlight possible areas of early intervention.…”