Predictive performance of CT hounsfield units and MRI vertebral bone quality score following single-level lumbar spinal fusion surgery: which is better.

OBJECTIVE

This study aimed to compare the predictive performance of CT-derived Hounsfield units (HU) and MRI-based vertebral bone quality (VBQ) scores for pedicle screw loosening (PSL) following single-level lumbar spinal fusion in patients with various types of degenerative lumbar disorders.

METHODS

A retrospective analysis was conducted on patients who underwent transforaminal lumbar interbody fusion (TLIF) at our institution between April 2021 and December 2023. PSL was identified on lumbar X-ray obtained at 12-month follow-up, defined as a radiolucent zone of ≥ 1 mm around the pedicle screw. VBQ score and HU value were measured using preoperative MRI and CT, respectively. Receiver operating characteristic (ROC) curve analysis was performed to evaluate and compare the predictive capabilities of HU and VBQ for PSL.

RESULTS

Across all patients (n = 154), the area under the curve (AUC) of the VBQ score (AUC = 0.807; 95% confidence interval (CI): 0.727-0.888; P < 0.001) exceeded those of the CT HU value (AUC = 0.702; 95% CI: 0.598-0.806; P = 0.001), although the difference was not statistically significant (PAUC = 0.168). In the lumbar spinal stenosis (LSS) subgroup (n = 65), AUC of VBQ score (AUC = 0.887; 95% CI: 0.793-0.980; P < 0.001) was larger than those of the CT HU value (AUC = 0.686; 95% CI: 0.532-0.841; P = 0.034), with significant difference (PAUC = 0.050).

CONCLUSION

VBQ and HU scores exhibit differing predictive capabilities for PSL across distinct types of lumbar degenerative disease. Notably, VBQ demonstrated superior predictive performance in the LSS subgroup. These findings suggest VBQ may be a valuable adjunct in preoperative bone quality assessment and surgical decision-making for LSS patients.