Vertebral Bone Quality Score and Postoperative Lumbar Lordosis Associated with Need for Reoperation After Lumbar Fusion

Using advanced imaging to measure bone density, compression fracture risk, and risk for construct failure after spine surgery

Low bone mineral density (BMD) can predispose to vertebral body compression fractures and postoperative instrumentation failure. DEXA is considered the gold standard for measurement of BMD, however it is not obtained for all spine surgery patients preoperatively. There is a growing body of evidence suggesting that more routinely acquired spine imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) can be opportunistically used to measure BMD. Here we review available studies that assess the validity of opportunistic screening with CT-derived Hounsfield Units (HU) and MRI-derived vertebral vone quality (VBQ) to measure BMD of the spine as well the utility of these measures in predicting postoperative outcomes. Additionally, we provide screening thresholds based on HU and VBQ for prediction of osteopenia/ osteoporosis and postoperative outcomes such as cage subsidence, screw loosening, proximal junctional kyphosis, and implant failure.

Adding Vertebral Bone Quality to the Fusion Risk Score: Does It Improve Predictions of Postoperative Complications?

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

The current study evaluates whether the addition of the Vertebral Bone Quality (VBQ) score to the Fusion Risk Score (FRS) improves its ability to predict perioperative outcomes.

SUMMARY OF BACKGROUND DATA

The FRS was developed to assess preoperative risk in patients undergoing thoracic and lumbar fusions. It includes patient-derived and surgical variables, but it does not include one that directly accounts for bone health. The VBQ score allows assessment of bone quality and has been shown to correlate to DEXA-measured bone mineral density (BMD) scores.

METHODS

The VBQ score was weighted based on a regression model and then added to the FRS (FRS/VBQ). The ability of the two scores to predict the outcomes was then assessed using the area under the curve (AUC).

PATIENT SAMPLE

Patients undergoing elective thoracic and lumbar spinal fusion from January 2019 to June 2020 were included.

OUTCOME MEASURES

The study evaluated various perioperative adverse outcomes, including major and minor adverse events, discharge other than home, extended length of stay, 90-day emergency department visits, 90-day readmission, and 90-day and 2-year reoperation rates.

RESULTS

A total of 353 met the inclusion and exclusion criteria. The FRS/VBQ demonstrated improved predictive ability compared with the FRS alone when evaluating 90-day reoperation. Both scores showed fair predictive ability for any adverse event, major adverse events, minor adverse events, and 2-year reoperation rates, with AUCs ranging from 0.700 to 0.737. Both had poor predictive ability for the other outcomes.

CONCLUSIONS

Adding VBQ to the FRS significantly enhances its predictive accuracy for reoperation rate. This updated risk score provides a more comprehensive understanding of a patient's preoperative risk profile, aiding both patients and physicians in assessing surgical risks and optimizing outcomes through preoperative risk stratification.

LEVEL OF EVIDENCE

3.

Correlations among MRI-based cervical and thoracic vertebral bone quality score, CT-based Hounsfield Unit score, and DEXA t-score in assessment of bone mineral density

BACKGROUND

Further optimization of the validated vertebral bone quality (VBQ) score using magnetic resonance imaging (MRI) may expand its clinical utility for bone mineral density (BMD) assessment. This study evaluated the correlations among cervical and thoracic VBQ scores, the validated Hounsfield Unit (HU) measured on computed tomography (CT), and dual-energy x-ray absorptiometry (DEXA) values.

METHODS

We retrieved the medical and radiographic records of 165 patients who underwent synchronous MRI of the cervical and thoracic spine, as well as DEXA and CT imaging of the spine obtained within 1 year of each other between 2015 and 2022. Radiographic data consisted of the MRI-based cervical and thoracic VBQ scores, CT-based HU, and DEXA T-scores of the spine and hip. Patient age, sex, body mass index (BMI), and ethnicity were also obtained.

RESULTS

Mean cervical and thoracic VBQ scores were 3.99 ± 1.68 and 3.82 ± 2.11, respectively. Mean HU and DEXA T-scores of the spine and hip were 135.75 ± 60.36, -1.01 ± 1.15, and -0.47 ± 2.27. All correlations among VBQ, HU, and DEXA were insignificant except for weak correlations between cervical and thoracic VBQ, and cervical VBQ and HU. No correlations were observed between radiographic scores and patient age or BMI. No differences based on ethnicity or sex were observed with respect to cervical or thoracic VBQ, HU, or DEXA.

CONCLUSION

Cervical and thoracic VBQ scores are distinct from Hounsfield Unit and DEXA values. VBQ scoring in the cervical and thoracic spine is not influenced by patient age, ethnicity, sex, or BMI.

The influence of osteoporosis on mechanical complications in lumbar fusion surgery: a systematic review

Background

Adults undergoing spine surgery often have underlying osteoporosis, which may be a risk factor for postoperative complications. Although these associations have been described, osteoporosis remains profoundly underdiagnosed and undertreated in the spine surgery population. A thorough, comprehensive systematic review summarizing the relationships between bone mineral density (BMD) and specific complications of lumbar fusion surgery could be a valuable resource for raising awareness and supporting clinical practice changes.

Methods

PubMed, Embase, and Web of Science databases were searched for original clinical research articles reporting on BMD, or surrogate measure, as a predictor of complications in adults undergoing elective lumbar fusion for degenerative disease or deformity. Endpoints included cage subsidence, screw loosening, pseudarthrosis, vertebral fracture, junctional complications, and reoperation.

Results

A total of 71 studies comprising 12,278 patients were included. Overall, considerable heterogeneity in study populations, methods of bone health assessment, and definition and evaluation of clinical endpoints precluded meta-analysis. Nevertheless, low BMD was associated with higher rates of implant failures like cage subsidence and screw loosening, which were often diagnosed with concomitant pseudarthrosis. Osteoporosis was also a significant risk factor for proximal junctional kyphosis, particularly due to fracture. Many studies found surgical site-specific BMD to best predict focal complications. Functional outcomes were inconsistently addressed.

Conclusions

Our findings suggest osteoporosis is a significant risk factor for mechanical complications of lumbar fusion. These results emphasize the importance of preoperative osteoporosis screening, which allows for medical and surgical optimization of high-risk patients. This review also highlights current practical challenges facing bone health evaluation in patients undergoing elective surgery. Future prospective studies using standardized methods are necessary to strengthen existing evidence, identify optimal predictive thresholds, and establish specialty-specific practice guidelines. In the meantime, an awareness of the surgical implications of osteoporosis and utility of preoperative screening can provide for more informed, effective patient care.

Comparison of predictive value for cage subsidence between MRI-based endplate bone quality and vertebral bone quality scores following transforaminal lumbar interbody fusion: a retrospective propensity-matched study

BACKGROUND CONTEXT

Cage subsidence after lumbar fusion can lead to many adverse outcomes. Low bone mineral density (BMD) is a widely recognized risk factor for cage subsidence. Conventional methods can predict and evaluate BMD, but there are many shortcomings. Recently, MRI-based assessment of bone quality in specific parts of the vertebral body has been proposed, including scores for vertebral bone quality (VBQ) and endplate bone quality (EBQ). However, the predictive accuracy of the two scoring systems for cage subsidence after transforaminal lumbar interbody fusion (TLIF) remains unknown. Therefore, we investigated MRI-based VBQ and EBQ scores for assessing bone quality and compared their predictive value for cage subsidence after TLIF.

PURPOSE

To compare the predictive value between MRI-based VBQ and EBQ scores for cage subsidence after TLIF.

STUDY DESIGN/SETTING

A retrospective case-control study.

PATIENTS SAMPLE

Patients with degenerative lumbar diseases underwent single-level TLIF at our medical center between 2014 and 2020, all of whom had preoperative MRIs available.

OUTCOMES MEASURES

Cage subsidence, disc height, VBQ score, EBQ score, upper and lower vertebral body bone quality (UL-VBQ) score.

METHODS

Data were retrospectively examined for a consecutive sample of 346 patients who underwent TLIF at our medical center between 2014 and 2020. Patients who subsequently experienced cage subsidence or not were matched to each other based on propensity scoring, and the two matched groups (52 patients each) were compared using conditional logistic regression to investigate the association between the potential radiographic factors and cage subsidence. Scores for VBQ and EBQ were assessed for their ability to predict cage subsidence in the matched patients based on the area under the receiver operative characteristic curve (AUC).

RESULTS

Among matched patients, those who suffered cage subsidence had significantly higher VBQ score (3.7 vs 3.1, p<.001) and EBQ score (5.0 vs 4.3, p<.001), and regression linked greater risk of subsidence to higher VBQ score (OR 4.557, 95% CI 1.076-19.291, p=.039) and higher EBQ score (OR 5.396, 95% CI 1.158-25.146, p=.032). A cut-off VBQ score of 3.4 predicted the cage subsidence among matched patients with an AUC of 0.799, sensitivity of 84.6%, and specificity of 69.2%. A cut-off EBQ score of 4.7 predicted subsidence with an AUC of 0.829, sensitivity of 76.9%, and specificity of 82.7%.

CONCLUSION

Higher VBQ and EBQ scores are associated with a greater risk of cage subsidence following TLIF, and EBQ may perform better because of greater specificity.

Bone Quality as Measured by Hounsfield Units More Accurately Predicts Proximal Junctional Kyphosis than Vertebral Bone Quality Following Long-Segment Thoracolumbar Fusion

OBJECTIVE

To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6).

METHODS

Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK.

RESULTS

Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106).

CONCLUSIONS

In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.

Application of a Magnetic Resonance Imaging-Based Lumbar Vertebral Bone Quality Scoring System in Patients with Degenerative Lumbar Scoliosis

BACKGROUND

Although dual-energy X-ray absorptiometry is still the gold standard for diagnosing osteoporosis, it can lead to inaccurate bone mineral density measurements due to lumbar degeneration and scoliosis. Many researchers have investigated diagnostic methods for osteoporosis in patients with degenerative lumbar scoliosis (DLS). This study aimed to investigate the differences between conventional vertebral bone quality (VBQ) scores and modified VBQ scores in patients with DLS and the influence of lumbar scoliosis on VBQ scores.

METHODS

We retrospectively collected the clinical and radiological data of 68 patients with DLS admitted to Sun Yat-sen Memorial Hospital from July 2018 to April 2023. The patients were classified into one of 2 groups based on the T score of the left femoral neck. VBQ scores relative to cerebrospinal fluid at different levels, VBQ scores on different planes and single-level VBQ scores were compared. Receiver operating characteristic analysis was also performed. Different modified VBQ scores were compared between the moderate scoliosis group (10°

RESULTS

There were no significant differences in VBQ scores relative to cerebrospinal fluid at different levels (P = 0.983), on different planes (P = 0.832) or at single-level (P = 0.996). All the VBQ scores were negatively correlated with the T score of the left femoral neck. There were no significant differences in the modified VBQ scores between the moderate and severe scoliosis groups.

CONCLUSIONS

Different modified VBQ scores can be used as supplementary methods for diagnosing osteoporosis in patients with DLS. Lumbar scoliosis may not significantly affect the VBQ score.

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Key Words

• Bone mineral density
• Degenerative lumbar scoliosis
• Magnetic resonance imaging
• Osteoporosis
• Vertebral bone quality score

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MESH Headings

• Humans
• Scoliosis/diagnostic imaging
• Female
• Lumbar Vertebrae/diagnostic imaging
• Male
• Aged
• Retrospective Studies
• Middle Aged
• Magnetic Resonance Imaging/methods
• Bone Density
• Absorptiometry, Photon/methods
• Osteoporosis/diagnostic imaging
• Osteoporosis/complications
• Aged, 80 and over

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Affiliation(s)

Wanli Zheng Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Weitao Han Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Song Jin Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Mingxi Zhu Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Zhengqi Huang Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Tianyu Qin Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Ming Shi Department of Spine Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
Bo Gao Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
Wei Ye Department of Spine Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.

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Systematic Review and Meta-Analysis of the Effect of Osteoporosis on Reoperation Rates and Complications after Surgical Management of Lumbar Degenerative Disease

BACKGROUND

There is considerable heterogeneity in findings and a lack of consensus regarding the interplay between osteoporosis and outcomes in patients with lumbar degenerative spine disease. Therefore, the purpose of this systematic review and meta-analysis was to gather and analyze existing data on the effect of osteoporosis on radiographic, surgical, and clinical outcomes following surgery for lumbar degenerative spinal disease.

METHODS

A systematic review was performed to determine the effect of osteoporosis on the incidence of adverse outcomes after surgical intervention for lumbar degenerative spinal diseases. The approach focused on the radiographic outcomes, reoperation rates, and other medical and surgical complications. Subsequently, a meta-analysis was performed on the eligible studies.

RESULTS

The results of the meta-analysis suggested that osteoporotic patients experienced increased rates of adjacent segment disease (ASD; p=0.015) and cage subsidence (p=0.001) while demonstrating lower reoperation rates than non-osteoporotic patients (7.4% vs. 13.1%; p=0.038). The systematic review also indicated that the length of stay, overall costs, rates of screw loosening, and rates of wound and other medical complications may increase in patients with a lower bone mineral density. Fusion rates, as well as patient-reported and clinical outcomes, did not differ significantly between osteoporotic and non-osteoporotic patients.

CONCLUSIONS

Osteoporosis was associated with an increased risk of ASD, cage migration, and possibly postoperative screw loosening, as well as longer hospital stays, incurring higher costs and an increased likelihood of postoperative complications. However, a link was not established between osteoporosis and poor clinical outcomes.

Preoperative Assessment of Bone Density Using MRI-Based Vertebral Bone Quality Score Modified for Patients Undergoing Cervical Spine Surgery

STUDY DESIGN

Diagnostic accuracy study.

OBJECTIVES

Previous studies have reported the clinical application of the Vertebral Bone Quality (VBQ) scores for assessing bone density in operative lumbar spine patients. We aim to explore whether the method could be modified and applicable for patients undergoing cervical spine surgery.

METHODS

Adult patients receiving cervical spine surgery for degenerative diseases between September 2020 and March 2022 with non-contrast T1-weighted MRI and DEXA were included. Correlation between cervical VBQ scores and DEXA T-scores was analyzed using Pearson's correlation. Student's t test was used to present the discrepancy between the VBQ of patients with normal bone density (T ≥ -1.0) and patients with osteopenia/osteoporosis (T < -1.0). Statistical significance was set at P < .05.

RESULTS

Eighty-three patients (20 patients with T ≥ -1.0 vs 63 patients with T < -1.0 ) were included. Significant difference was found between the cervical VBQ between groups (2.99 ± .79 vs 3.80 ± .81, P < .001). Interclass correlation coefficient for inter-rater reliability was .82 (95% CI: .70-.93) and .91(95% CI: .84-.97) for intra-rater reliability. The area under the ROC curve was .78 (95% CI: .65-.90). The DEXA T-score of the femoral neck, total hip and the lowest DEXA T-score were found to be significantly correlated with the cervical VBQ score according to Pearson correlation analysis (P < .001).

CONCLUSIONS

This is the first study to apply the VBQ method to assess the bone density in preoperative cervical spine patients. Cervical VBQ scores were significantly correlated with DEXA T-score. With an overall accuracy of .78, the radiation-free and cost-effective method could be a potential tool for screening patients with osteopenia and osteoporosis before surgery.

Preoperative MRI-based endplate quality: a novel tool for predicting cage subsidence after anterior cervical spine surgery

PURPOSE

The objective of this study was to examine the predictive value of a newly developed MRI-based Endplate Bone Quality (EBQ) in relation to the development of cage subsidence following anterior cervical discectomy and fusion (ACDF).

METHODS

Patients undergoing ACDF for degenerative cervical diseases between January 2017 and June 2022 were included. Correlation between EBQ scores and segmental height loss was analyzed using Pearson's correlation. ROC analyses were employed to ascertain the EBQ cut-off values that predict the occurrence of cage subsidence. Multivariate logistic regression analyses were conducted to identify the risk factors associated with postoperative cage subsidence.

RESULTS

23 individuals (14.56%) exhibited the cage subsidence after ACDF. In the nonsubsidence group, the average EBQ and lowest T-score were determined to be 4.13 ± 1.14 and - 0.84 ± 1.38 g/cm2 respectively. In contrast, the subsidence group exhibited a mean EBQ and lowest T-score of 5.38 ± 0.47 (p < 0.001) and - 1.62 ± 1.34 g/cm2 (p = 0.014), respectively. There was a significant positive correlation (r = 0.798**) between EBQ and the segmental height loss. The EBQ threshold of 4.70 yielded optimal sensitivity (73.9%) and specificity (93.3%) with AUC of 0.806. Furthermore, the lowest T-score (p = 0.045, OR 0.667) and an elevated cervical EBQ score (p < 0.001, OR 8.385) were identified as significant risk factors for cage subsidence after ACDF.

CONCLUSIONS

The EBQ method presents itself as a promising and efficient tool for surgeons to assess patients at risk of cage subsidence and osteoporosis prior to cervical spine surgery, utilizing readily accessible patient data.

Evaluation of the modified MRI vertebral bone quality score for bone quality in lumbar degenerative disorders

OBJECTIVE

The traditional VBQ scoring method may lead to overestimation due to the concentration of intravertebral fat and vascular structures in the posterior half of vertebral bodies, potentially resulting in false-positive outcomes. This study aims to modify the measurement method of VBQ score (Modified-VBQ) and evaluate its effectiveness in evaluating bone quality of lumbar degenerative diseases.

METHODS

Retrospective analysis was conducted on clinical data from patients undergoing lumbar surgery for degenerative diseases between September 2022 and September 2023. Preoperative lumbar t1-weighted Magnetic resonance imaging was used for both modified and traditional VBQ scoring. Computed tomography (CT) images and dual-energy X-ray absorptiometry (DEXA) data were collected through the picture archiving and communication system. The effectiveness of the modified VBQ score was evaluated, considering P < 0.05 as statistically significant.

RESULTS

The study included 212 patients, revealing a significant difference between the modified VBQ and VBQ scores (P < 0.0001). Notably, patients with a history of hyperlipidemia exhibited a significant difference between the two scores (P = 0.0037). The area under the ROC curve (AUC) for the modified VBQ was 0.86, surpassing the VBQ score (AUC = 0.74). Linear regression analysis demonstrated a moderate to strong correlation between the modified VBQ and DEXA T-score (r = - 0.49, P < 0.0001) and a high correlation with CT Hounsfield units (HU) values (r = - 0.60, P < 0.0001).

CONCLUSION

The modified VBQ score provides a simple, effective, and relatively accurate means of assessing bone quality in lumbar degenerative diseases. Preoperative implementation of the modified VBQ score facilitates rapid screening for patients with abnormal bone quality.

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

BACKGROUND AND OBJECTIVE

Posterior cervical fusion is the surgery of choice when fusing long segments of the cervical spine. However, because of the limited presence of this pathology, there is a paucity of data in the literature about the postoperative complications of distal junctional kyphosis (DJK). We aimed to identify and report potential associations between the preoperative cervical vertebral bone quality (C-VBQ) score and the occurrence of DJK after posterior cervical fusion.

METHODS

The authors retrospectively reviewed records of patients who underwent posterior cervical fusion at a single hospital between June 1, 2010, and May 31, 2020. Patient data were screened to include patients who were >18 years old, had baseline MRI, had baseline standing cervical X-ray, had immediate postoperative standing cervical X-ray, and had clinical and radiographic follow-ups of >1 year, including a standing cervical X-ray at least 1 year postoperatively. Univariate analysis was completed between DJK and non-DJK groups, with multivariate regression completed for relevant clinical variables. Simple linear regression was completed to analyze correlation between the C-VBQ score and total degrees of kyphosis angle change.

RESULTS

Ninety-three patients were identified, of whom 19 (20.4%) had DJK and 74 (79.6%) did not. The DJK group had a significantly higher C-VBQ score than the non-DJK group (2.97 ± 0.40 vs 2.26 ± 0.46; P < .001). A significant, positive correlation was found between the C-VBQ score and the total degrees of kyphosis angle change (r 2 = 0.26; P < .001). On multivariate analysis, the C-VBQ score independently predicted DJK (odds ratio, 1.46; 95% CI, 1.27-1.67; P < .001).

CONCLUSION

We found that the C-VBQ score was an independent predictive factor of DJK after posterior cervical fusion.

MRI-based vertebral bone quality score: relationship with age and reproducibility

Vertebral bone quality (VBQ) score is an opportunistic measure of bone mineral density using routine preoperative MRI in spine surgery. VBQ score positively correlates with age and is reproducible across serial scans. However, extrinsic factors, including MRI machine and protocol, affect the VBQ score and must be standardized.

PURPOSE

The purposes of this study were to determine whether VBQ score increased with age and whether VBQ remained consistent across serial MRI studies obtained within 3 months.

METHODS

This retrospective study evaluated 136 patients, age 20-69, who received two T1-weighted lumbar MRI within 3 months of each other between January 2011 and December 2021. VBQ(L1-4) score was calculated as the quotient of L1-L4 signal intensity (SI) and L3 cerebral spinal fluid (CSF) SI. VBQ(L1) score was calculated as the quotient of L1 SI and L1 CSF SI. Regression analysis was performed to determine correlation of VBQ(L1-4) score with age. Coefficient of variation (CV) was used to determine reproducibility between VBQ(L1-4) scores from serial MRI scans.

RESULTS

One hundred thirty-six patients (mean ± SD age 44.9 ± 12.5 years; 53.7% female) were included in this study. Extrinsic factors affecting the VBQ score included patient age, MRI relaxation time, and specific MRI machine. When controlling for MRI relaxation/echo time, the VBQ(L1-4) score was positively correlated with age and had excellent reproducibility in serial MRI with CV of 0.169. There was excellent agreement (ICC > 0.9) of VBQ scores derived from the two formulas, VBQ(L1) and VBQ(L1-4).

CONCLUSION

Extrinsic factors, including MRI technical factors and age, can impact the VBQ(L1-4) score and must be considered when using this tool to estimate bone mineral density (BMD). VBQ(L1-4) score was positively correlated with age. Reproducibility of the VBQ(L1-4) score across serial MRI is excellent especially when controlling for technical factors, supporting use of the VBQ score in estimating BMD. The VBQ(L1) score was a reliable alternative to the VBQ(L1-4) score.

A meta-analysis of the value of MRI-based VBQ scores for evaluating osteoporosis

Objective

Osteoporosis is the most common skeletal disease in humans. Early onset of osteoporosis is usually asymptomatic, so early diagnosis is critical. The purpose of this study was to analyze the value of MRI-based VBQ scores for evaluating osteoporosis.

Methods

We searched PubMed, Embase, the Cochrane Library databases, Web of Science, and some Chinese electronic databases for published articles and the ClinicalTrials.gov site for completed but unpublished studies on evaluating the value of MRI-based VBQ scores for evaluating osteoporosis. We calculated the summarized sensitivity, specificity, the ROC curve (AUC) values and their 95% confidence intervals (CIs) using MetaDiSc 1.4 software and STATA.

Results

Our study included 8 studies involving 999 patients of which 660 patients were diagnosed with osteopenia/osteoporosis, and 339 patients were identified as having normal BMD. The pooled sensitivity was 0.809 (95% CI, 0.777-0.838, I 2  = 78.8%), the pooled specificity was 0.640 (95% CI, 0.587-0.691, I 2  = 85.9%), and the pooled AUC was 0.8375.

Conclusion

MRI-based VBQ scores provided high sensitivity and moderate specificity in detecting osteoporosis. Opportunistic use of VBQ scores could be considered, e.g. before lumbar spine surgery.

Prospero registration number

CRD42022377024.

Vertebral bone quality different in magnetic resonance imaging parameters

OBJECTIVE

This was a single-center retrospective study that aimed to measure the vertebral bone quality (VBQ) in people of all ages and compare changes in VBQ across ages. Differences in VBQ under various MRI parameters were compared.

METHODS

We first screened patients without underlying disease and no history of fractures who underwent lumbar MRI in our center in the past four years. Over the span of 10 years, 200 patients (100 males and 100 females) were randomly recruited into each cohort to undergo 1.5 T and 3.0 T MRI scans. Subsequently, we tabulated the number of patients admitted to our hospital with OVCF over the past four years. There were 30 healthy adults under 4 times of MRI scans in different parameters to determine the differentiation of VBQ. The 30 healthy adults were recruited to validate the differentiation of VBQ under various parameters.

RESULTS

A total of 2400 patients without OVCF and 405 patients with OVCF were enrolled. The VBQ value of 1.5 T was significantly higher compared with that of 3.0 T (2.769 ± 0.494 > 2.199 ± 0.432, P < 0.0001). VBQ of 43.31 kHz in 1.5 T was significantly lower than that of 35.36 kHz (2.447 ± 0.350 < 2.632 ± 0.280, P < 0.05). The differentiation of VBQ in 1.5 T and 3.0 T was validated using results of healthy adults.

CONCLUSIONS

VBQ is an effective tool for differentiating patients with OVCF and can be used as a primary screening tool for osteoporosis. However, VBQ is significantly affected by magnetic field intensity and bandwidth and cannot achieve its universality as it originally proposed.

MRI-based Vertebral Bone Quality Score for Osteoporosis Screening Based on Different Osteoporotic Diagnostic Criteria Using DXA and QCT

In this study, we aim to evaluate the correlation between T score measured by dual X-ray absorptiometry (DXA), volumetric bone mineral density (vBMD) derived from quantitative computed tomography (QCT) and MRI-based vertebral bone quality (VBQ), explore the diagnostic performance of VBQ in osteoporosis and determine the recognition value of VBQ in osteoporotic fracture in a relatively large cohort of elderly patients scheduled to undergo spinal surgery. A total of 260 patients were enrolled in the study. DXA and QCT were used to evaluate osteoporotic status. We calculated the lumbar VBQ score, analyzed the correlation between T score, vBMD and VBQ, and explored whether VBQ was an influential factor of bone quality and fracture by binary logistic regression as well as the diagnostic performance of VBQ in osteoporosis and fracture by ROC curve. VBQ was negatively correlated with vBMD and T score. (r = - 0.487 vs. r = - 0.220). The VBQ score was a risk factor for osteoporosis under the QCT diagnostic criteria (OR = 2.245, 95% CI 1.456-3.460) and osteoporotic fractures (OR = 1.496, 95% CI 1.097-2.040). It exhibited superior discriminant performance for osteoporosis diagnosed by QCT, with a cutoff value of 3.70 and an AUC of 0.7354. Its cutoff value for osteoporotic fractures was 3.72, and its AUC was 0.6717. In a cohort of elderly patients scheduled to undergo spinal surgery, the VBQ score was more strongly associated with vBMD than the T score and could identify patients with osteoporosis and corresponding vertebral compression fracture (VCF).

Assessing lumbar vertebral bone quality: a methodological evaluation of CT and MRI as alternatives to traditional DEXA

PURPOSE

The purpose of this study was to investigate the impact of various methods on the assessment of vertebral bone quality.

METHODS

A consecutive series of 427 candidates for lumbar disc replacement with lumbar DEXA and MRI and/or CT scans were included. Two measurement techniques were used on CTs-a sagittal and axial. From axial images, the upper, mid, and lower portions of each vertebral body were measured. Four MRI vertebral bone quality (VBQ) calculations were generated using separate equations.

RESULTS

All CT measures were highly correlated with each other, regardless of measurement or calculation method (range 0.925-0.995). Sagittal measurements were highly correlated with axial (r = 0.928, p < 0.001). CT values were correlated with DEXA (range 0.446-0.534). There was no benefit to measuring multiple axial images of each vertebral body vs. just midbody (r = 0.441 and 0.455, respectively). No MRI VBQ values were highly correlated with DEXA (r =  -  0.103, p = 0.045). In receiver operating curve analysis, the area under the curve ranged from 0.539 to 0.558, indicating poor ability of VBQ to identify osteoporosis/osteopenia.

CONCLUSION

CT produced values more closely related to DEXA, while MRI was less reliable for osteoporosis/osteopenia screening. On CT, there was no benefit to making multiple measurements for each vertebral body to calculate a composite. Measuring sagittal CT images produced values similar to axial and required less time. While assessing bone quality from existing images rather than getting an additional DEXA scan is appealing, the methods of measuring these images needs standardization to maximize their utility.

Opportunistic Evaluation of Trabecular Bone Texture by MRI Reflects Bone Mineral Density and Microarchitecture

CONTEXT

Many individuals at high risk for fracture are never evaluated for osteoporosis and subsequently do not receive necessary treatment. Utilization of magnetic resonance imaging (MRI) is burgeoning, providing an ideal opportunity to use MRI to identify individuals with skeletal deficits. We previously reported that MRI-based bone texture was more heterogeneous in postmenopausal women with a history of fracture compared to controls.

OBJECTIVE

The present study aimed to identify the microstructural characteristics that underlie trabecular texture features.

METHODS

In a prospective cohort, we measured spine volumetric bone mineral density (vBMD) by quantitative computed tomography (QCT), peripheral vBMD and microarchitecture by high-resolution peripheral QCT (HRpQCT), and areal BMD (aBMD) by dual-energy x-ray absorptiometry. Vertebral trabecular bone texture was analyzed using T1-weighted MRIs. A gray level co-occurrence matrix was used to characterize the distribution and spatial organization of voxelar intensities and derive the following texture features: contrast (variability), entropy (disorder), angular second moment (ASM; uniformity), and inverse difference moment (IDM; local homogeneity).

RESULTS

Among 46 patients (mean age 64, 54% women), lower peripheral vBMD and worse trabecular microarchitecture by HRpQCT were associated with greater texture heterogeneity by MRI-higher contrast and entropy (r ∼ -0.3 to 0.4, P < .05), lower ASM and IDM (r ∼ +0.3 to 0.4, P < .05). Lower spine vBMD by QCT was associated with higher contrast and entropy (r ∼ -0.5, P < .001), lower ASM and IDM (r ∼ +0.5, P < .001). Relationships with aBMD were less pronounced.

CONCLUSION

MRI-based measurements of trabecular bone texture relate to vBMD and microarchitecture, suggesting that this method reflects underlying microstructural properties of trabecular bone. Further investigation is required to validate this methodology, which could greatly improve identification of patients with skeletal fragility.

MRI-based vertebral bone quality score compared to quantitative computed tomography bone mineral density in patients undergoing cervical spinal surgery

PURPOSE

The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was introduced as a bone quality marker in the lumbar spine. Prior studies showed that it could be utilized as a predictor of osteoporotic fracture or complications after instrumented spine surgery. The objective of this study was to evaluate the correlation between VBQ scores and bone mineral density (BMD) measured by quantitative computer tomography (QCT) in the cervical spine.

METHODS

Preoperative cervical CT and sagittal T1-weighted MRIs from patients undergoing ACDF were retrospectively reviewed and included. The VBQ score in each cervical level was calculated by dividing the signal intensity of the vertebral body by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images and correlated with QCT measurements of the C2-T1 vertebral bodies. A total of 102 patients (37.3% female) were included.

RESULTS

VBQ values of C2-T1 vertebrae strongly correlated with each other. C2 showed the highest VBQ value [Median (range) 2.33 (1.33, 4.23)] and T1 showed the lowest VBQ value [Median (range) 1.64 (0.81, 3.88)]. There was significant weak to moderate negative correlations between and VBQ Scores for all levels [C2: p < 0.001; C3: p < 0.001; C4: p < 0.001; C5: p < 0.004; C6: p < 0.001; C7: p < 0.025; T1: p < 0.001].

CONCLUSION

Our results indicate that cervical VBQ scores may be insufficient in the estimation of BMDs, which might limit their clinical application. Additional studies are recommended to determine the utility of VBQ and QCT BMD to evaluate their potential use as bone status markers.

Use of MRI-based vertebral bone quality score (VBQ) of S1 body in bone mineral density assessment for patients with lumbar degenerative diseases

PURPOSE

To evaluate the use of the modified and simplified vertebral bone quality (VBQ) method based on T1-weighted MRI images of S1 vertebrae in assessing bone mineral density (BMD) for patients with lumbar degenerative diseases.

METHODS

We reviewed the preoperative data of patients with lumbar degenerative diseases undergoing lumbar spine surgery between January 2019 and June 2022 with available non-contrast T1-weighted magnetic resonance imaging (MRI), computed tomography (CT) images and dual-energy X-ray absorptiometry (DEXA). S1 vertebral bone quality scores (S1 VBQ) and S1 CT Hounsfield units were measured with picture archiving and communication system (PACS). One-way ANOVA was applied to present the discrepancy between the S1 VBQ of patients with normal bone density (T-score ≥ - 1.0), osteopenia (- 2.5 < T-score < - 1.0) and osteoporosis (T-score ≤ - 2.5). The receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic performance of S1 VBQ in distinguishing low BMD. Statistical significance was set at p < 0.05.

RESULTS

A total of 207 patients were included. The S1 VBQ were significantly different between groups (p < 0.001). Interclass correlation coefficient for inter-rater reliability was 0.86 (95% CI 0.78-0.94) and 0.94(95% CI 0.89-0.98) for intra-rater reliability. According to the linear regression analysis, the S1 VBQ has moderate-to-strong correlations with DEXA T-score (r = - 0.48, p < 0.001). The area under the ROC curve indicated a predictive accuracy of 82%. A sensitivity of 77.25% with a specificity of 70% could be achieved for distinguishing low BMD by setting the S1 VBQ cutoff as 2.93.

CONCLUSIONS

The S1 VBQ was a promising tool in distinguishing poor bone quality in patients with lumbar degenerative diseases, especially in cases where the previously reported VBQ method based on L1-L4 was not available. S1 VBQ score could be useful as opportunistic assessment for screening and complementary evaluation to DEXA T-score before surgery.

Peripheral cortical bone density predicts vertebral bone mineral properties in spine fusion surgery patients

Spine fusion surgery is one of the most common orthopedic procedures, with over 400,000 performed annually to correct deformities and pain. However, complications occur in approximately one third of cases. While many of these complications may be related to poor bone quality, it is difficult to detect bone abnormalities prior to surgery. Areal BMD (aBMD) assessed by DXA may be artifactually high in patients with spine pathology, leading to missed diagnosis of deficits. In this study, we related preoperative imaging characteristics of both central and peripheral sites to direct measurements of bone quality in vertebral biopsies. We hypothesized that pre-operative imaging outcomes would relate to vertebral bone mineralization and collagen properties. Pre-operative assessments included DXA measurements of aBMD of the spine, hip, and forearm, central quantitative computed tomography (QCT) of volumetric BMD (vBMD) at the lumbar spine, and high resolution peripheral quantitative computed tomography (HRpQCT; Xtreme CT2) measurements of vBMD and microarchitecture at the distal radius and tibia. Bone samples were collected intraoperatively from the lumbar vertebrae and analyzed using Fourier-transform Infrared (FTIR) spectroscopy. Bone samples were obtained from 23 postmenopausal women (mean age 67 ± 7 years, BMI 28 ± 8 kg/m2). We found that patients with more mature bone by FTIR, measured as lower acid phosphate content and carbonate to phosphate ratio, and greater collagen maturity and mineral maturity/crystallinity (MMC), had greater cortical vBMD at the tibia and greater aBMD at the lumbar spine and one-third radius. Our data suggests that bone quality at peripheral sites may predict bone quality at the spine. As bone quality at the spine is challenging to assess prior to surgery, there is a great need for additional screening tools. Pre-operative peripheral bone imaging may provide important insight into vertebral bone quality and may foster identification of patients with bone quality deficits.

A Novel Cervical Vertebral Bone Quality Score Independently Predicts Cage Subsidence After Anterior Cervical Diskectomy and Fusion

BACKGROUND

Surgeons can preoperatively assess bone quality using dual-energy X-ray absorptiometry or computed tomography; however, this is not feasible for all patients. Recently, a MRI-based scoring system was used to evaluate the lumbar spine's vertebral bone quality.

OBJECTIVE

To create a similar MRI-based scoring system for the cervical spine (C-VBQ), correlate C-VBQ scores with computed tomography-Hounsfield units (HU), and evaluate the utility of this scoring system to independently predict cage subsidence after single-level anterior cervical diskectomy and fusion (ACDF).

METHODS

Demographic, procedure-related, and radiographic data were collected for patients. Pearson correlation test was used to determine the correlation between C-VBQ and HU. Cage subsidence was defined as ≥3 mm loss of fusion segmental height. A multivariate logistic regression model was built to determine the correlation between potential risk factors for subsidence.

RESULTS

Of 59 patients who underwent single-level ACDF, subsidence was found in 17 (28.8%). Mean C-VBQ scores were 2.22 ± 0.36 for no subsidence levels and 2.83 ± 0.38 ( P < .001) for subsidence levels. On multivariate analysis, a higher C-VBQ score was significantly associated with subsidence (odds ratio = 1.85, 95% CI = 1.39-2.46, P < .001) and was the only significant independent predictor of subsidence after ACDF. There was a significant negative correlation between HU and C-VBQ (r 2 = -0.49, P < .001).

CONCLUSION

We found that a higher C-VBQ score was significantly associated with cage subsidence after ACDF. Furthermore, there was a significant negative correlation between C-VBQ and HU. The C-VBQ score may be a valuable tool for assessing preoperative bone quality and independently predicting cage subsidence after ACDF.

MRI-based vertebral bone quality score for the assessment of osteoporosis in patients undergoing surgery for lumbar degenerative diseases

PURPOSE

To explore the value of vertebral bone quality (VBQ) scores in diagnosing osteoporosis in patients with lumbar degeneration.

METHODS

A retrospective analysis was conducted of 235 patients treated with lumbar fusion surgery at the age of ≥ 50; they were divided into a degenerative group and a control group according to the severity of degenerative changes on three-dimensional computed tomography. The L1-4 vertebral body and L3 cerebrospinal fluid signal intensities in the T1-weighted lumbar magnetic resonance imaging (MRI) image were recorded, and the VBQ score was calculated. Demographics, clinical data, and dual-energy X-ray absorptiometry (DXA) indicators were recorded, and the VBQ value was compared with bone density and T-score using the Pearson correlation coefficient. The VBQ threshold was obtained according to the control group and compared with the efficacy of osteoporosis diagnosis based on DXA.

RESULTS

A total of 235 patients were included in the study, and the age of the degenerative group was older than that of the control group (61.8 vs. 59.4, P = 0.026). The VBQ score of the control group suggested a higher correlation with the bone mineral density (BMD) value and T-score (r = - 0.611 and - 0.62, respectively). The BMD value and T-score in the degenerative group were higher than those in the control group (P < 0.05). Receiver-operating characteristic curve analysis showed that the VBQ score had a good predictive ability for osteoporosis (AUC = 0.818), with a sensitivity of 93% and a specificity of 65.4%. Among the undiagnosed osteoporosis patients with T-score, the VBQ score after adjusting the threshold was higher in the degenerative group (46.9% vs. 30.8%).

CONCLUSIONS

Emerging VBQ scores can reduce the interference caused by degenerative changes compared to traditional DXA measures. Screening for osteoporosis in patients undergoing lumbar spine surgery provides new ideas.

Prediction of Pedicle Screw Loosening Using an MRI-Based Vertebral Bone Quality Score in Patients with Lumbar Degenerative Disease

OBJECTIVE

To explore a new magnetic resonance imaging (MRI)-based bone quality assessment method for predicting pedicle screw loosening in the lumbar spine.

METHODS

We reviewed 174 patients aged ≥50 years who were treated for lumbar degenerative diseases using posterior lumbar interbody fusion. All patients were followed-up for ≥12 months. Based on the presence of radiolucent areas on follow-up MRI images, the patients were divided into loosening and nonloosening groups. The vertebral bone quality (VBQ) score was calculated using T1-weighted MRI images. Demographic data, health history, and radiological parameters were also recorded and compared between the 2 groups. Logistic regression analysis was used to predict the independent risk factors affecting screw loosening.

RESULTS

Screw loosening occurred in 29.88% (52/174) of patients. A total of 83 screws (9.18%, 83/904) were loosened. There were differences in the age, fixation length, fixation at S1, preoperative and postoperative PI-LL, PT, preoperative LL, lowest bone mineral density (BMD), and VBQ scores (P < 0.05) between the nonloosening and loosening groups. In the logistic regression, the VBQ score (OR = 1.02 per point; 95% CI: 1.01-1.03; P < 0.001) was identified as an independent factor influencing screw loosening.

CONCLUSIONS

As an independent risk factor for screw loosening after lumbar spine fusion, the VBQ score provides a new noninvasive protocol for assessing bone quality during surgical planning.

Comparison of cervical, thoracic, and lumbar vertebral bone quality scores for increased utility of bone mineral density screening

PURPOSE

To evaluate the associations among the validated lumbar vertebral bone quality (VBQ) score, and cervical and thoracic VBQ scores.

METHODS

Radiographic records of 100 patients who underwent synchronous MRI of the cervical, thoracic, and lumbar spine were retrieved. DEXA-validated lumbar VBQ was calculated using median signal intensity (MSI) of the L1-L4 vertebrae and L3 CSF. VBQ was derived as the quotient of MSI_L1-L4 divided by MSI_CSF. Cervical and thoracic VBQ were similarly obtained using C3-C6 and C5 CSF, and T5-T8 and T7 CSF, respectively. Paired sample t-tests were used to evaluate differences among regional VBQ scores. Independent sample t-tests were used to identify sex differences in VBQ. Regression models with one-way analysis of variance (ANOVA) were constructed to identify associations among all permutations of anthropometric and regional VBQ measures.

RESULTS

Mean cervical, thoracic, and lumbar VBQ scores were 3.06 ± 0.89, 2.60 ± 0.77, and 2.47 ± 0.61, respectively. Mean differences of .127 (p = 0.045) and - 0.595 (p < 0.001) were observed between thoracic and lumbar, and cervical and lumbar VBQ scores. Correlations of 0.324, 0.356, and 0.600 (p < 0.001) were found between cervical and lumbar, cervical and thoracic, and thoracic and lumbar VBQ scores. Regression with ANOVA predicting lumbar VBQ in relation to cervical and thoracic VBQ demonstrated R Square values of 0.105 and 0.360 (p < 0.001), and β coefficient values of 0.471 and 0.217 (p < 0.001), respectively.

CONCLUSION

Thoracic VBQ provides values representative of the validated lumbar VBQ score. Cervical VBQ scores are distinct from lumbar VBQ scores and do not provide adequate surrogate values of lumbar VBQ.

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

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.

The predictive value of a novel site-specific MRI-based bone quality assessment, endplate bone quality (EBQ), for severe cage subsidence among patients undergoing standalone lateral lumbar interbody fusion

BACKGROUND CONTEXT

Studies have shown that site-specific bone density measurements had more predictive value for complications than standard whole-region measurements. Recently, MRI-based assessments of vertebral bone quality (VBQ) were introduced. However, there have been few studies that investigate the association between site-specific MRI bone assessment and osteoporosis-related complications in patients undergoing lumbar interbody fusion. In this work, we created a novel site-specific MRI-based assessment of the endplate bone quality (EBQ) and assessed its predictive value for severe cage subsidence following standalone lateral lumbar interbody fusion (SA-LLIF).

PURPOSE

To investigate the predictive value of a novel MRI-based bone assessment for severe cage subsidence after SA-LLIF.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Patients who underwent SA-LLIF from 2008 to 2019 at a single, academic institution with available preoperative lumbar CT and T1-weighted MRIs.

OUTCOME MEASURES

Association between EBQ and severe subsidence after SA-LLIF.

METHODS

We retrospectively reviewed the records of SA-LLIF patients treated between 2008 and 2019. EBQ was measured using preoperative non-contrast T1-weighted MRIs of the lumbar spine. EBQ was defined as the average value of signal intensity of both endplates divided by that of the cerebrospinal fluid space at the level of L3. Bivariate and multivariable analyses with generalized linear mixed models were performed and set binary severe subsidence as the outcome.

RESULTS

Two hundred five levels in 89 patients were included. Fifty levels (24.4%) demonstrated severe subsidence. Bone mineral density measured by quantitative computed tomography was significantly lower in the subsidence group. Both VBQ and EBQ were significantly higher in the subsidence group. The EBQ plus Modic change (MC) model demonstrated that the effect of EBQ was independent of MC. In multivariate analyses adjusted with QCT-vBMD, EBQ showed a significant association with cage subsidence whereas VBQ only showed a marginal trend. The EBQ-based prediction model for severe subsidence showed better goodness of fit compared to the VBQ-based model.

CONCLUSIONS

High EBQ was an independent factor for severe cage subsidence after SA-LLIF and the EBQ-based model showed better goodness of fit compared to VBQ- or MC-based models. EBQ assessment before SA-LLIF may provide insight into a patient's risk for severe subsidence.

Novel MRI-based vertebral bone quality score as a predictor of cage subsidence following transforaminal lumbar interbody fusion

OBJECTIVE

Decreased bone mineral density as measured by dual-energy x-ray absorptiometry (DEXA) has been reported to be associated with cage subsidence following transforaminal lumbar interbody fusion (TLIF). However, DEXA is not often available or routinely performed before surgery. A novel MRI-based vertebral bone quality (VBQ) score has been developed and reported to be correlated with DEXA T-scores. The authors investigated the ability of the VBQ score to predict cage subsidence and other risk factors associated with this complication.

METHODS

In this retrospective study, the authors reviewed the records of patients who had undergone single-level TLIF from March 2014 to October 2015 and had a follow-up of more than 2 years. Cage subsidence was measured as postoperative disc height loss and was graded according to the system proposed by Marchi et al. The MRI-based VBQ score was measured on T1-weighted images. Univariable analysis and multivariable binary logistic regression analysis were performed. Ad hoc analysis with receiver operating characteristic curve analysis was performed to assess the predictive ability of the significant continuous variables. Additional analyses were used to determine the correlations between the VBQ score and T-scores and between the significant continuous variables and the amount of cage subsidence.

RESULTS

Among 242 patients eligible for study inclusion, 111 (45.87%) had cage subsidence after the index operation. Multivariable logistic regression analyses demonstrated that an increased VBQ score (OR 14.615 ± 0.377, p < 0.001), decreased depth ratio (OR 0.011 ± 1.796, p = 0.013), and the use of kidney-shaped cages instead of bullet-shaped cages (OR 2.766 ± 0.358, p = 0.008) were associated with increased cage subsidence. The VBQ score was shown to significantly predict cage subsidence with an accuracy of 85.6%. The VBQ score was found to be moderately correlated with DEXA T-scores of the total hip (r = -0.540, p < 0.001) and the lumbar spine (r = -0.546, p < 0.001). The amount of cage subsidence was moderately correlated with the VBQ score (r = 0.512, p < 0.001).

CONCLUSIONS

Increased VBQ scores, posteriorly placed cages, and kidney-shaped cages were risk factors for cage subsidence. The VBQ score was shown to be a good predictor of cage subsidence, was moderately correlated with DEXA T-scores for the total hip and lumbar spine, and also had a moderate correlation with the amount of cage subsidence.

Comparison of Posterior Pedicle Screw Fixation and Lateral Fixation in the Extreme Lateral Interbody Fusion in Lumbar Degenerative Disease Patients with Osteopenia or Osteoporosis

OBJECTIVE

Nowadays, with the increasing proportion of osteoporosis in patients with lumbar degenerative diseases, doctors are facing the choice of intraoperative internal fixation methods. The purpose of this study was to compare and assess the clinical results of posterior bilateral pedicle screw fixation and lateral fixation in the extreme lateral interbody fusion (XLIF) in patients with osteopenia or osteoporosis.

METHODS

The retrospective review was performed on 67 degenerative lumbar diseases patients with osteopenia or osteoporosis who underwent XLIF in our hospital from January 2018 to July 2021. Patients in this study were classified into lateral screw (LS) group, lateral self-locking plate (LP) group, and bilateral pedicle screw (BPS) group. The functional evaluation factors containing Japanese Orthopaedic Association (JOA) score, visual analogue scale (VAS) of leg pain, and VAS of low back pain, radiological factors such as disc height (DH), lumbar lordotic (LL) angle, segmental lordotic (SL) angle, cage subsidence degree and interbody fusion degree were compared.

RESULTS

Primary outcomes: no differences were observed with regards to the incidence of complications among LS, LP and BS group (P < 0.05). The JOA and leg pain VAS were significantly improved after operation (P < 0.05) and all groups demonstrated similar improvements in the leg pain VAS and JOA score (P > 0.05). When comparing VAS of leg pain and JOA scores, no differences were identified among LS, LP and BPS groups (P > 0.05). There are four thigh sensory complaint, one hip flexor weakness and one thigh pain occurred and no death was observed. There were significantly better DH, LL angle, SL angle, cage subsidence degree and interbody fusion degree in the BPS group than in LS and LP groups 1 year after surgery (P < 0.05). The DH loss ratio, LL angle loss ratio, SL angle loss ratio in the BPS group was significantly lower than in the LP and LS groups (P < 0.05). The 12-month SL angle improvement rate in the BPS group was significantly higher than in the LP and LS groups (20.20 ± 14.69, 0.73 ± 4.68, 6.20 ± 12.31, P < 0.05).

SECONDARY OUTCOMES

the BPS patients had significantly worse intraoperative blood loss and operation time than LS and LP patients (P < 0.05).

CONCLUSION

In lumbar diseases patients with osteopenia or osteoporosis, the bilateral pedicle screw fixation has better orthopedic effect than lateral internal fixation, and can better maintain the stability of the spine in the long-term follow-up, which is a better choice in XLIF surgery.

Bone quality in patients with osteoporosis undergoing lumbar fusion surgery: analysis of the MRI-based vertebral bone quality score and the bone microstructure derived from microcomputed tomography

BACKGROUND CONTEXT

Osteoporosis is a risk factor for instrumentation failure in spine surgery. Bone strength is commonly assessed by bone mineral density (BMD) as a surrogate marker. However, BMD represents only a portion of bone strength and does not capture the qualitative dimensions of bone. Recently, the magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score was introduced as a novel marker of bone quality. However, it is still unclear if the VBQ score correlates with in-vivo bone microstructure.

PURPOSE

The aims of the study were (1) to demonstrate differences in MRI-based (VBQ) and in-vivo (microcomputed tomography; μCT) bone quality between osteopenic/osteoporotic and normal bone, (2) to show the correlation between VBQ, bone microstructure and volumetric BMD (vBMD), and (3) to determine the predictive value of the VBQ score for the prevalence of osteopenia/osteoporosis.

STUDY DESIGN/SETTING

Retrospective cross-sectional study.

PATIENT SAMPLE

267 patients who underwent posterior lumbar fusion surgery from 2014 to 2021 at a single academic institution. Bone biopsies were harvested intraoperatively in 118 patients.

OUTCOME MEASURES

VBMD, VBQ score, and bone microstructure parameters derived from μCT.

METHODS

Quantitative computed tomography (QCT) measurements were performed at the lumbar spine and the L1/L2 average was used to categorize patients with a vBMD ≤120mg/cm³ as osteopenic/osteoporotic. The VBQ score was determined by dividing the median signal intensity of the L1-L4 vertebrae by the signal intensity of the cerebrospinal fluid using sagittal T1-weighted MRI scans. Intraoperative bone biopsies from the posterior superior iliac spine were obtained and evaluated with μCT. VBQ scores and μCT parameters were compared between the normal and the osteopenic/osteoporotic group. Correlations between VBQ score, μCT parameters and vBMD were assessed with Spearman's correlation (ρ). Receiver operating characteristic (ROC) analysis was performed to determine the VBQ score as a predictor for osteopenia/osteoporosis. Multiple linear regression analysis with vBMD L1/L2 as outcome was used to identify independent predictors from VBQ, μCT parameters and demographics.

RESULTS

267 patients (55.8% female, age 63.3 years, BMI 29.7 kg/m²; n=118 with bone biopsy) with a prevalence of osteopenia/osteoporosis of 65.2% were analyzed. In the osteopenic/osteoporotic group the VBQ score, structured model index (SMI), and trabecular separation (Tb.Sp) were significantly higher, whereas bone volume fraction (BV/TV), connectivity density (Conn.D) and trabecular number (Tb.N) were significantly lower. There were significant correlations between VBQ and μCT parameters ranging from ρ=-.387 to ρ=0.314 as well as between vBMD and μCT parameters ranging from ρ=-.425 to ρ=.421, and vBMD and VBQ (ρ=-.300, p<.001). ROC analysis discriminated osteopenia/osteoporosis with a sensitivity of 84.7% and a specificity of 40.6% at a VBQ score threshold value of 2.18. Age, BV/TV and trabecular thickness (Tb.Th), but not VBQ, were significant independent predictors for vBMD (corrected R²=0.434).

CONCLUSIONS

This study demonstrated for the first time that the VBQ score is associated with trabecular microstructure determined by μCT. The bone microstructure and VBQ score were significantly different in patients with impaired vBMD. However, the ability to predict osteopenia/osteoporosis with the VBQ score was moderate. The VBQ score appears to reflect additional bone quality characteristics and might have a complementary role to vBMD. This enhances our understanding of the biological background of the radiographic VBQ score and might be a take-off point to evaluate the clinical utility of it as non-invasive screening tool for bone quality.

Preoperative MRI-based vertebral bone quality (VBQ) score assessment in patients undergoing lumbar spinal fusion

BACKGROUND CONTEXT

The importance of bone status assessment in spine surgery is well recognized. The current gold standard for assessing bone mineral density is dual-energy X-ray absorptiometry (DEXA). However, DEXA has been shown to overestimate BMD in patients with spinal degenerative disease and obesity. Consequently, alternative radiographic measurements using data routinely gathered during preoperative evaluation have been explored for the evaluation of bone quality and fracture risk. Opportunistic quantitative computed tomography (QCT) and more recently, the MRI-based vertebral bone quality (VBQ) score, have both been shown to correlate with DEXA T-scores and predict osteoporotic fractures. However, to date the direct association between VBQ and QCT has not been studied.

PURPOSE

The objective of this study was to evaluate the correlation between VBQ and spine QCT BMD measurements and assess whether the recently described novel VBQ score can predict the presence of osteopenia/osteoporosis diagnosed with QCT.

STUDY DESIGN/SETTING

Cross-sectional study using retrospectively collected data.

PATIENT SAMPLE

Patients undergoing lumbar fusion from 2014-2019 at a single, academic institution with available preoperative lumbar CT and T1-weighted MRIs were included.

OUTCOME MEASURES

Correlation of the VBQ score with BMD measured by QCT, and association between VBQ score and presence of osteopenia/osteoporosis.

METHODS

Asynchronous QCT measurements were performed. The average L1-L2 BMD was calculated and patients were categorized as either normal BMD (>120 mg/cm³) or osteopenic/osteoporotic (≤120 mg/cm³). The VBQ score was calculated by dividing the median signal intensity of the L1-L4 vertebral bodies by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images. Inter-observer reliability testing of the VBQ measurements was performed. Demographic data and the VBQ score were compared between the normal and osteopenic/osteoporotic group. To determine the area-under-curve (AUC) of the VBQ score as a predictor of osteopenia/osteoporosis receiver operating characteristic (ROC) analysis was performed. VBQ scores were compared with QCT BMD using the Pearson's correlation.

RESULTS

A total of 198 patients (53% female) were included. The mean age was 62 years and the mean BMI was 28.2 kg/m². The inter-observer reliability of the VBQ measurements was excellent (ICC of 0.90). When comparing the patients with normal QCT BMD to those with osteopenia/osteoporosis, the patients with osteopenia/osteoporosis were significantly older (64.9 vs. 56.7 years, p<.0001). The osteopenic/osteoporotic group had significantly higher VBQ scores (2.6 vs. 2.2, p<.0001). The VBQ score showed a statistically significant negative correlation with QCT BMD (correlation coefficient = -0.358, 95% CI -0.473 - -0.23, p<.001). Using a VBQ score cutoff value of 2.388, the categorical VBQ score yielded a sensitivity of 74.3% and a specificity of 57.0% with an AUC of 0.7079 to differentiate patients with osteopenia/osteoporosis and with normal BMD.

CONCLUSIONS

We found that the VBQ score showed moderate diagnostic ability to differentiate patients with normal BMD versus osteopenic/osteoporotic BMD based on QCT. VBQ may be an interesting adjunct to clinically performed bone density measurements in the future.

Average Lumbar Hounsfield Units Predicts Osteoporosis-Related Complications Following Lumbar Spine Fusion

STUDY DESIGN

Retrospective Study.

OBJECTIVE

To compare methods of assessing pre-operative bone density to predict risk for osteoporosis related complications (ORC), defined as proximal junctional kyphosis, pseudarthrosis, accelerated adjacent segment disease, reoperation, compression fracture, and instrument failure following spine fusions.

METHODS

Chart review of primary posterior thoracolumbar or lumbar fusion patients during a 7 year period. Inclusion criteria: preoperative dual-energy x-ray absorptiometry (DXA) test within 1 year and lumbar CT scan within 6 months prior to surgery with minimum of 1 year follow-up. Exclusion criteria: <18 years at time of index procedure, infection, trauma, malignancy, skeletal dysplasia, neuromuscular disorders, or anterior-posterior procedures.

RESULTS

140 patients were included. The average age was 67.9 years, 83 (59.3%) were female, and 45 (32%) had an ORC. There were no significant differences in patient characteristics between those with and without an ORC. Multilevel fusions were associated with ORCs (46.7% vs 26.3%, p = 0.02). Patients with ORCs had lower DXA t-scores (-1.62 vs -1.10, p = 0.003) and average Hounsfield units (HU) (112.1 vs 148.1, p ≤ 0.001). Multivariable binary logistic regression analysis showed lower average HU (Adj. OR 0.00 595% CI 0.0001-0.1713, p = 0.001) was an independent predictor of an ORC. The odds of an ORC increased by 1.7-fold for every 25 point decrease in average HU.

CONCLUSIONS

The gold standard for assessing bone mineral density has been DXA t-scores, but the best predictor of ORC remains unclear. While both lower t-scores and average HU were associated with ORC, only HU was an independent predictor of ORC.

Opportunistic Use of Lumbar Magnetic Resonance Imaging for Osteoporosis Screening

Magnetic resonance imaging (MRI) is a routine assessment before spine surgery. We found that the opportunistic use of MRI with the vertebral bone quality (VBQ) score has good diagnostic ability, with a threshold value of VBQ > 3.0, in recognizing patients who may need further osteoporosis evaluation.

INTRODUCTION

The purpose of this study was to determine whether the opportunistic use of magnetic resonance imaging (MRI) is useful for identifying spine surgical patients who need further osteoporosis evaluation.

METHODS

This retrospective study evaluated 83 thoracolumbar spine surgery patients age ≥ 50 who received T1-weighted MRI. Opportunistic MRI was evaluated with the vertebral bone quality (VBQ) score, VBQ (fat) score, and signal-to-noise ratio (SNR). Each uses the median L1-L4 vertebral body signal intensities (SI) divided by either the L3 cerebrospinal fluid (CSF) SI, average SI of the L1 and S1 dorsal fat, or standard deviation (SD) of the background SI dorsal to the skin. Single-level VBQ was calculated as the ratio of the L1 vertebral body and L1 CSF SIs. Receiver-operator curve analysis was performed to determine diagnostic ability.

RESULTS

The mean age was 70.10, 80% were female, and 96% were Caucasian. The mean ± SD VBQ, single-level VBQ, VBQ (fat), and SNR were 3.39 ± 0.68, 3.56 ± 0.81, 3.95 ± 1.89, and 113.18 ± 77.26, respectively. Using area under the curve, the diagnostic ability of VBQ, single-level VBQ, VBQ (fat), and SNR for clinical osteoporosis were 0.806, 0.779, 0.608, and 0.586, respectively. Diagnostic threshold values identified with optimal sensitivity and specificity were VBQ of 2.95 and single-level VBQ of 3.06.

CONCLUSION

Opportunistic use of MRI is a simple, effective tool that may help recognize patients who are at risk for complications related to bone disease. A VBQ > 3.0 can identify patients who need additional diagnostic evaluation.

Interrater and Intrarater Reliability of the Vertebral Bone Quality Score

BACKGROUND

Vertebral bone quality had a significant impact on postoperative outcomes in spinal fusion surgery. New magnetic resonance imaging-based measures, such as the Vertebral Bone Quality (VBQ) score, may allow for bone quality assessment without the radiation associated with conventional testing. In the present study, we sought to assess the intrarater and interrater reliability of VBQ scores calculated by medical professionals and trainees.

METHODS

Thirteen reviewers of various specialties and levels of training were recruited and asked to calculate VBQ scores for 30 patients at 2 time points separated by 2 months. Scored volumes were acquired from patients treated for both degenerative and oncologic indications. Intrarater and interrater agreement, quantified by intraclass correlation coefficient (ICC), was assessed using 2-way random effects modeling. Square-weight Cohen κ and Kendall Tau-b were used to determine whether raters assigned similar scores during both evaluations.

RESULTS

All raters showed moderate to excellent reliability for VBQ score (ICC 0.667-0.957; κ0.648-0.921) and excellent reliability for all constituent components used to calculate VBQ score (ICC all ≥0.97). Interrater reliability was also found to be good for VBQ score on both the first (ICC = 0.818) and second (ICC = 0.800) rounds of assessment; scores for the constituent component all had ICC values ≥0.97 for the constituent components.

CONCLUSIONS

The VBQ score appears to have both good intrarater and interrater reliability. In addition, there appeared to be no correlation between score reliability and level of training. External validation and further investigations of its ability to accurately model bone biomechanical properties are necessary.