49 - The association between high preoperative MRI-based vertebral bone quality (VBQ) score and titanium mesh cage subsidence anterior cervical corpectomy and fusion

Background: Recently, the MRI-based vertebral bone quality (VBQ) score has been shown to correlate with Hounsfeld units (HU) value, DEXA T-scores and predict osteoporotic fractures. Preoperative cervical CT value is an independent correlative factor for early titanium mesh cage (TMC) subsidence after anterior cervical corpectomy and fusion (ACCF). However, to date the direct association between VBQ and TMC subsidence has not been studied.

Objective: To study the predictive effect of VBQ score in the cervical vertebral body derived from MRI on the early TMC subsidence after ACCF.

Methods: A total of 120 patients have been enrolled who underwent ACCF at one institution between December 2013 and December 2019. We collected date included age, gender, body mass index (BMI), disease type, surgical segment, VBQ score of the vertebral body and endplate, and radiology parameters. VAS, JOA, and NDI were used to assess clinical efficacy. Univariate analysis was performed to screen the influencing factors of TMC subsidence, and then logistic regression was used to find out the independent risk factors. The ROC curve and area under curve (AUC) were used to analyze the VBQ score to predict the TMC subsidence.

Results: A total of 120 patients who accepted ACCF were included in this study, and early titanium mesh cage subsidence was demonstrated in 45 patients. The subsidence rate was 37.5%. The logistic regression analysis proved that the VBQ score of the lower vertebral body was an independent risk of TMC subsidence. Using a VBQ score cutoff value of 2.189, the categorical VBQ score yielded a sensitivity of 79.7% and a specificity of 69.2% with an AUC of 0.783 to differentiate patients with subsidence and with non-subsidence.

Conclusion: Preoperative cervical VBQ score is an independent correlative factor for early TMC subsidence after ACCF, and patients with a high VBQ score of the inferior vertebral body of the operative segment have a higher risk of TMC subsidence in the early postoperative period.