Effect of the lumbar scoliosis on the results of dual-energy X-ray absorptiometry

Preliminary study on the effect of lumbar axial rotation on bone mineral density measured by DXA and QCT

Currently, the relationship between axial rotation of the vertebrae and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) remains controversial. The aim of this study is to quantitatively assess the effect of vertebral rotation on volumetric bone mineral density (v-BMD) and areal bone mineral density (a-BMD), further to propose the corrected strategies. To achieve this, a phantom, which was rotated from 0° to 25° in 5° increments, was utilized. Bone mineral content (BMC), a-BMD, v-BMD, and projected area (p-AREA) were measured. The Kruskal-Wallis non-parametric test or one-way ANOVA was used to examine the differences in variables between the different groups. The Pearson and Spearman correlation was used to test the relationships between quantitative parameters and rotated angles. Linear regression analysis was used to evaluate the relationship between angles and quantitative parameters. The findings indicate that, as the angle increased, a-BMD and v-BMD decreased (P < 0.001) , and the p-AREA increased (P < 0.001), but the BMC stays constant. The rotated angle was negative correlated (r = - 0.925, P < 0.001) with a-BMD and v-BMD (r = - 0.880, P < 0.001), positive (r = 0.930, P =  < 0.001) correlated with p-AREA. The linear regression analysis showed that a-BMD = 0.808-0.01 × Angle and v-BMD = 151.808-1.588 × Angle. This study showed that, axial rotation might lead to a lower measured for a-BMD and v-BMD, it should be modified. This gives clinicians some insights into how to deal with osteoporosis in scoliosis patients. It's essential for clinicians to incorporate these findings into their diagnostic processes to prevent potential misdiagnosis and over-treatment of osteoporosis.

MRI-based vertebral bone quality score as a novel bone status marker of patients with adolescent idiopathic scoliosis

To investigate the application of MRI-based vertebral bone quality (VBQ) score in assessing bone mineral density (BMD) for patients with adolescent idiopathic scoliosis (AIS). We reviewed the data of AIS patients between January 2021 and October 2023 with MRI, whole-spine plain radiographs, quantitative computed tomography (QCT) and general information. VBQ score was calculated using T1-weighted MRI. Univariate analysis was applied to present the differences between variables of patients with normal BMD group (QCT Z-score > - 2.0) and low BMD group (QCT Z-score ≤ - 2.0). The correlation between VBQ score and QCT Z-score was analyzed with Pearson correlation test. A multivariate logistic regression model was used to determine the independent factors related to low BMD. Receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic performance of VBQ score in distinguishing low BMD. A total of 136 AIS patients (mean age was 14.84 ± 2.10 years) were included, of which 41 had low BMD. The low BMD group had a significantly higher VBQ score than that in normal group (3.48 ± 0.85 vs. 2.62 ± 0.62, P < 0.001). The VBQ score was significantly negative correlated with QCT Z score (r =  - 0.454, P < 0.001). On multivariate analysis, VBQ score was independently associated with low BMD (OR: 4.134, 95% CI 2.136-8.000, P < 0.001). The area under the ROC curve indicated that the diagnostic accuracy of the VBQ score for predicting low BMD was 81%. A sensitivity of 65.9% with a specificity of 88.4% could be achieved for distinguishing low BMD by setting the VBQ score cutoff as 3.18. The novel VBQ score was a promising tool in distinguishing low BMD in patients with AIS and could be useful as opportunistic assessment for screening and complementary evaluation to QCT before surgery.

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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Relationship between postural changes, osteoarthritis and bone mineral density in postmenopausal women

OBJECTIVES

To assess the relationship between postural changes, osteoarthritis (OA) and bone mineral density (BMD) in postmenopausal women.

METHODS

A total of 127 Brazilian women, aged 45 years or older, were included in this retrospective study. Subjects were divided in two groups: study group with postural changes (SG) and control group without postural changes (CG). Possible postural changes considered were scoliosis, kyphosis and lordosis. All women underwent BMD assessment and OA was identified at the region of the hip and lumbar spine by dual energy X-ray absorptiometry (DXA) analysis.

RESULTS

SG was older (66.0 ± 7.3 years) than the CG (61.0 ± 8.6 years). In the entire sample we found thirteen women with OA and low BMD. Overall, the lumbar spine area was more affected by OA than the hip. The value of BMD T-score accounted for up to 77% of the changes observed in the SG group.

CONCLUSION

Postural changes identified in women are directly related to aging and associated with bone loss and joint degeneration. Postural changes may be the primary sign of frailty as a result of body adaptation to pain related to musculoskeletal diseases.

Hounsfield unit for assessing asymmetrical loss of vertebral bone mineral density and its correlation with curve severity in adolescent idiopathic scoliosis

Background

Low bone mass concomitantly occurs in patients with adolescent idiopathic scoliosis (AIS) and can persist until skeletal maturity. The purpose of this study was to assess the asymmetrical loss of vertebral bone mineral density (vBMD) and its correlation with curve severity in patients with AIS using Hounsfield unit (HU) values measured from computed tomography scans.

Methods

A total of 93 AIS patients were retrospectively recruited. The HU values of the vertebral body (VB-HU) and pedicle screw trajectory (PST-HU) were measured from four vertebrae above (Apex − 4) to four below (Apex + 4) the apical vertebra (Apex) of the major curve. The VB-HU and PST-HU at the upper end vertebra, Apex, and lower end vertebra within the concave and convex sides of the major and minor curves and stable vertebrae were obtained.

Results

A significant correlation was found between the Cobb angle and VB-HU at the periapical levels of the major curve. VB-HU and PST-HU at periapical levels were significantly greater within the concavity than the convexity of both major and minor curves. The asymmetric ratios of VB-HU and PST-HU were significantly correlated with the major curve Cobb angle, peaked at the apex, and gradually diminished from the apex to the end vertebrae. The asymmetrical loss of vBMD aggravated with the progression of curve severity, presenting as VB-HU, significantly decreased within the convexity and insignificantly decreased within the concavity of the major curve.

Conclusion

The asymmetrical loss of vBMD was associated with the progression of curve severity in AIS. For patients with severe AIS, the distraction of the pedicle screws at the concave side should be a priority in correcting the major curve, and supplemental anchors and larger-sized screws should be placed within the convex side around the apex of the major curve to reduce the risk of screw loosening after surgery.