Predictive value of different site-specific MRI-based assessments of bone quality for cage subsidence among patients undergoing oblique lumbar interbody fusion

OBJECTIVE The aim of this study was to investigate the predictive value of different site-specific MRI-based assessments of bone quality for cage subsidence among patients undergoing oblique lumbar interbody fusion (OLIF) with or without posterior internal fixation. METHODS The authors retrospectively reviewed the records of patients who underwent OLIF between 2017 and 2022. Endplate bone quality (EBQ), mean vertebral bone quality (MVBQ), and vertebral bone quality (VBQ) scores were measured using preoperative non-contrast-enhanced T1-weighted MRI of the lumbar spine. Logistic regression analysis was used to identify factors associated with cage subsidence. Receiver operating characteristic curve analysis was used to evaluate the value of different site-specific MRI-based assessments of bone quality in predicting cage subsidence. RESULTS Of the 124 patients who underwent OLIF, subsidence was found in 42 (33.9%). The VBQ, MVBQ, and EBQ scores were higher in the subsidence group than in the no-subsidence group. In the stand-alone OLIF (SA-OLIF) group, logistic regression analysis showed that the EBQ score was significantly associated with subsidence (OR 13.656, 95% CI 2.561-72.806; p = 0.002). Furthermore, the areas under the curve (AUCs) for using the VBQ, MVBQ, and EBQ scores and T-score to predict cage subsidence were 0.684, 0.683, 0.745, and 0.685, respectively. In the OLIF with posterior internal fixation (OLIF-PF) group, logistic regression analysis showed that the MVBQ score was significantly associated with subsidence (OR 8.301, 95% CI 2.064-33.385; p = 0.003). The AUCs for using the VBQ score, MVBQ score, and T-score to predict cage subsidence were 0.757, 0.774, and 0.685, respectively. CONCLUSIONS There are significant differences in the predictive value of different site-specific bone quality assessments for cage subsidence among patients undergoing OLIF. For SA-OLIF, the EBQ score is recommended, while for OLIF-PF, the VBQ score is preferable.