MRI-based vertebral bone quality score for predicting cage subsidence by assessing bone mineral density following transforaminal lumbar interbody fusion: a retrospective analysis

The diagnostic value of MRI-based vertebral bone quality score for osteoporosis or osteopenia in patients undergoing lumbar surgery: a meta-analysis

The importance of osteoporosis assessment before lumbar surgery is well recognized. The MRI-based Vertebral Bone Quality (VBQ) score is introduced to evaluate bone quality; however, its diagnostic value has not been well documented. The purpose of this meta-analysis was to summarize the diagnostic value of the VBQ score for osteoporosis or osteopenia in patients undergoing lumbar surgery. We comprehensively searched electronic databases for studies exploring the diagnostic accuracy of the VBQ score for osteoporosis/osteopenia in patients with lumbar disease following the PRISMA guidelines. The quality of the included studies was assessed. The VBQ scores were compared between the groups, and the pooled sensitivity, specificity, and summary receiver operating characteristic (ROC) were calculated. Publication bias was assessed, and meta-regression was conducted. We included 17 studies with a total of 2815 patients, with a mean age of 66.4 years and a percentage of females of 72.5%. According to the QUADAS-2 tool, the quality of the included studies was relatively high. The results showed a significantly higher VBQ score in the osteoporosis/osteopenia group compared with the control group. According to the mean VBQ cutoff value of 3.02 ± 0.38 for the diagnosis of osteoporosis, the pooled sensitivity and specificity were 0.76 and 0.74, respectively, and the AUC was 0.81. According to the mean VBQ cutoff value of 2.31 ± 0.18 for the diagnosis of osteopenia, the pooled sensitivity and specificity were 0.78 and 0.58, respectively, and the AUC was 0.76. The MRI-based VBQ score could provide useful information for identifying patients with low bone mass who need further evaluation. Future prospective studies are still needed to evaluate the complementary role of the VBQ score.

Low bone mineral density: a primer for the spine surgeon

Within spinal surgery, low bone mineral density is associated with several postoperative complications, such as proximal junctional kyphosis, pseudoarthrosis, and screw loosening. Although modalities such as CT and MRI can be utilized to assess bone quality, DEXA scans, the "Gold Standard" for diagnosing osteoporosis, is not routinely included in preoperative workup. With an increasing prevalence of osteoporosis in an aging population, it is critical for spine surgeons to understand the importance of evaluating bone mineral density preoperatively to optimize postoperative outcomes. The purpose of this state-of-the-art review is to provide surgeons a summary of the evaluation, treatment, and implications of low bone mineral density in patients who are candidates for spine surgery.

Novel MRI-Based Pedicle Bone Quality Score Independently Predicts Pedicle Screw Loosening after Degenerative Lumbar Fusion Surgery

Pedicle screw loosening after posterior lumbar fusion is associated with poor bone quality, which often determines screw pull-out strength, insertion torque, and vertebral body loading characteristics. Magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score were associated with poor bone quality. Current evidence suggests that pedicle bone quality (PBQ) has a greater impact on screw stability. However, the correlation between MRI-based PBQ score and screw loosening has not been reported.

PURPOSE

To introduce and evaluate an MRI-based PBQ score to determine its effectiveness in predicting pedicle screw loosening following lumbar fusion surgery.

METHODS

The retrospective study analyzed 244 patients who underwent posterior lumbar interbody fusion (PLIF) with pedicle screws between December 2017 and December 2021, with CT and MRI imaging before surgery. Data collected included patient demographics and preoperative radiological data. Radiographic screw loosening was measured at 12 months postoperatively. Clinical assessments included pain visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. The PBQ score was measured using MRI scans. We use univariate analysis for preliminary screening of the risk factors of screw loosening. Subsequent analysis involved multivariate logistic regression to identify independent predictive factors for screw loosening. We constructed the receiver operating characteristic (ROC) curve to ascertain the discriminative capacity of the PBQ score. The area under the curve (AUC) quantified its predictive accuracy. Additionally, we evaluated the association between PBQ score and screw loosening using Spearman's correlation analysis.

RESULTS

Overall, 244 patients who underwent PLIF with pedicle screw fixation participated in this study, including 35 in the loosening group and 209 in the non-loosening group. PBQ score in the loosening group was significantly higher than that in the non-loosening group. On multivariate logistic regression, the higher PBQ score (OR = 8.481, 95% CI: 3.158-22.774; p < 0.001) and the lower mean Hounsfield unit (HU) value of L1-4 (OR = 0.967, 95% CI 0.951-0.984; p < 0.001) were the variables that significantly predicted screw loosening. The AUC for the PBQ score and HU value were 0.751 (95% CI: 0.673-0.828) and 0.702 (95% CI: 0.612-0.791). The PBQ score optimal cutoff to differentiate patients with loosening and with non-loosening was calculated as 3.045 with a sensitivity of 85.7% and specificity of 76.9%, while the optimal cutoff of the HU value was 151.5 with a sensitivity of 64.6% and specificity of 89.5%.

CONCLUSIONS

The association between the PBQ score and the propensity for lumbar pedicle screw loosening was found to be substantial. As a predictive measure, the PBQ score outperformed the HU value in forecasting the likelihood of screw loosening post-posterior lumbar fusion.

Magnetic Resonance Imaging-Based Vertebral Bone Quality Score for Prediction of Cage Subsidence and Screw Loosening in Patients Undergoing Degenerative Lumbar Surgery: A Meta-analysis

OBJECTIVE

Poor bone quality is a risk factor for postoperative complications after degenerative lumbar fusion surgery. The magnetic resonance imaging-based vertebral bone quality (VBQ) score is a good tool for assessing bone quality, and this is the first meta-analysis performed to summarize the predictive value of the VBQ score for cage subsidence and screw loosening in patients undergoing degenerative lumbar surgery.

METHODS

Studies were comprehensively searched in electronic databases. The quality of the studies was assessed. The pooled sensitivity, specificity and summary receiver operating characteristic curve were calculated. Publication bias was assessed and meta-regression was conducted.

RESULTS

We ultimately included 9 studies with a total of 1,404 patients with a mean age of 60.4 years and a percentage of females of 57.0%. According to the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool to assess methodological quality, the quality of the included studies was relatively low and risks of bias might exist. Results showed that a high VBQ was significantly associated with cage subsidence and screw loosening, and risk factor analysis revealed that the merged odds ratio was 5.37 for cage subsidence and 3.87 for screw loosening. With a VBQ cutoff value of 3.34±0.45, the pooled sensitivity and specificity for the diagnosis of postoperative complications were 0.75 and 0.75, respectively, and the area under the curve was 0.82 (95% confidence interval, 0.78-0.85).

CONCLUSION

A high VBQ was associated with a high risk of cage subsidence and screw loosening in patients who underwent degenerative lumbar surgery. The VBQ score could be considered for identifying high-risk patients for further evaluation.

Cervical Vertebral Bone Quality Score Independently Predicts Zero-Profile Cage Subsidence After Single-Level Anterior Cervical Discectomy and Fusion

OBJECTIVE

This is the first study to evaluate the predictive value of the cervical vertebral bone quality (VBQ) score on zero-profile cage (ZPC)subsidence after anterior cervical discectomy and fusion (ACDF) using the Hounsfield units (HU) value of computed tomography as the reference.

METHODS

A total of 89 patients with at least 1 year of follow-up who underwent single-level ACDF with ZPC were retrospectively and consecutively included. VBQ and HU value were determined from preoperative T1-weighted magnetic resonance imaging and computed tomography. Subsidence was defined as ≥2 mm of migration of the cage into the superior or inferior endplate or both using lateral cervical spine radiography. The results were subjected to statistical analysis.

RESULTS

Subsidence was observed among 16 of the 89 study patients (Subsidence rate: 18.0%). The mean VBQ score was 2.94 ± 0.820 for patients with subsidence and 2.33 ± 0.814 for patients without subsidence. The multivariable analysis demonstrated that only an increased VBQ score (odds ratio: 1.823, 95% confidence interval : 0.918,3.620, P = 0.001) was associated with an increased rate of cage subsidence. There was a significant and moderate correlation between HU and VBQ (r = -0.507, P < 0.001). Using receiver operating characteristic curves, the area under the curve was 0.785, and the most appropriate threshold of VBQ was 2.68 (sensitivity 72.7%, specificity 82.1%).

CONCLUSIONS

The VBQ score may be a valuable tool for independently predicting ZPC subsidence after single-level ACDF.

Modic Changes Increase the Cage Subsidence Rate in Spinal Interbody Fusion Surgery: A Systematic Review and Network Meta-Analysis

OBJECTIVE

To compare the effect of different Modic changes (MC) grades on the cage subsidence rate after spinal interbody fusion surgery.

METHODS

We comprehensively searched the PubMed, Embase, and Web of Science databases from inception to August 13, 2023, for relevant randomized controlled trials and prospective and retrospective cohort studies. Review Manager 5.3 and STATA13.0 were used to conduct this meta-analysis. The subsidence rate was assessed using relative risk and 95% confidence intervals.

RESULTS

Six studies with a total of 716 segments were allocated to four groups according to the type of MC. The subsidence rate in the non-Modic changes (NMC) was significantly lower than that in the MC. The subsidence rate in the NMC was significantly lower than that in the MC in the subgroup of cages with extra instrumentation. No significant difference was identified between the 2 groups in the oblique lumbar interbody fusion subgroup. The subsidence rate in the NMC was significantly lower than that in the MC in the transforaminal lumbar interbody fusion subgroup. The subsidence rate in the NMC was significantly lower than that in the MC1 and MC2. We found no significant difference between NMC and MC3, MC1 and MC2, MC1 and MC3, or MC2 and MC3.

CONCLUSIONS

MC may be associated with a higher cage subsidence rate. With the increase in MC grades, the incidence of subsidence decreased gradually, but it was always higher than that in the NMC. Oblique lumbar interbody fusion may be a better choice for the treatment of lumbar degenerative disease with MC.