The Impact of Bone Mineral Density on Bone Metabolism and the Fracture Healing Process in Elderly Chinese Patients With Osteoporotic Vertebral Compression Fractures

Bone union-promoting effect of romosozumab in an ovariectomized rat posterolateral lumbar fusion model

Spinal fixation surgery has been increasingly performed in patients with osteoporosis. Romosozumab, a drug that was introduced in Japan recently, is known to possibly promote bone healing. However, few studies have reported the therapeutic effects of romosozumab in clinical practice in Japan. Therefore, here, we investigated the effects of romosozumab dosage on bone fusion promotion using an ovariectomized rat spinal fusion model. Eight-week-old female Sprague-Dawley rats were matched by body weight and divided into three groups: 1.0 romosozumab (R) group (Evenity®, 25 mg/kg), 1/10R group (Evenity®, 2.5 mg/kg), and control (C) group (saline). Subcutaneous injections were administered twice a week for 8 weeks postoperatively. Computed tomography scans were performed every 2 weeks from the time of surgery till 8 weeks postoperatively. The mean fusion rates in terms of volume were significantly higher in the R groups [1/10R, 1.0R] than in the C group from 4 weeks postoperatively. The rate of increase was significantly higher in the 1.0R group from 4 weeks postoperatively and in the 1/10R group from 6 weeks postoperatively, than in the C group. The proportion of trabecular bone area was approximately 1.5 times higher in the R groups than in the C group. No significant differences were observed between the R groups. Our results suggest that romosozumab stimulates bone growth at the graft site, and similar effects were achieved at 1/10 of the standard dosage.

Factors influencing further vertebral height loss following percutaneous vertebroplasty in osteoporotic vertebral compression fractures: A 1-year follow-up study

BACKGROUND

Osteoporotic vertebral compression fractures (OVCFs) contribute to back pain and functional limitations in older individuals, with percutaneous vertebroplasty (PVP) emerging as a minimally invasive treatment. However, further height loss post-PVP prompts investigation into contributing factors.

AIM

To investigate the factors associated with further height loss following PVP with cement augmentation in OVCF patients.

METHODS

A total of 200 OVCF patients who underwent successful PVP between January 2021 and December 2022 were included in this study. "Further height loss" during 1 year of follow-up in OVCF patients with bone edema was defined as a vertical height loss of ≥ 4 mm. The study population was divided into two groups for analysis: The "No Further Height Loss group (n = 179)" and the "Further Height Loss group (n = 21)."

RESULTS

In comparing two distinct groups of patients, significant differences existed in bone mineral density (BMD), vertebral compression degree, prevalence of intravertebral cleft (IVF), type of bone cement used, and cement distribution patterns. Results from binary univariate regression analysis revealed that lower BMD, the presence of IVF, cleft distribution of bone cement, and higher vertebral compression degree were all significantly associated with further height loss. Notably, the use of mineralized collagen modified-poly(methyl methacrylate) bone cement was associated with a significant reduction in the risk of further height loss. In multivariate regression analysis, lower BMD and the presence of IVF remained significantly associated with further height loss.

CONCLUSION

Further height loss following PVP in OVCF patients is influenced by a complex interplay of factors, especially lower BMD and the presence of IVF. These findings underscore the importance of assessing and managing these factors when addressing height loss following PVP in OVCF patients.

Effectiveness of bone-filled mesh bag technology and angle vertebroplasty in the treatment of osteoporotic thoracic vertebral compression fractures in the elderly

OBJECTIVE

To evaluate the effectiveness, pain level, and lung function in elderly patients with osteoporotic thoracic vertebral compression fractures using bone filling mesh bag technology compared to curved vertebroplasty.

METHODS

This retrospective analysis reviewed 72 elderly patients with osteoporotic thoracic vertebral compression fractures treated at Xindu District People's Hospital of Chengdu between February 2021 and January 2022. The patients were separated into two groups according to surgery approach: an observation group using bone filling mesh bag technology and a control group using curved vertebroplasty. The overall response rate, pain degree, pulmonary function, life quality grades, surgical indicators, and bone cement leakage rates of the two groups were evaluated.

RESULTS

The variation in overall response rate (P=0.420), pain degree (P=0.270), pulmonary function (peak expiratory flow: P=0.660, forced expiratory volume in the first second: P=0.775, forced vital capacity: 0.062), and life quality grades (physical health: P=0.949, social function: P=0.935, physiological function: P=0.970, vitality: P=0.778) between the observation group and the control group after treatment was not statistically meaningful. The Cobb angle (P<0.001) and vertebral height (P<0.001) of patients in the observation group were significantly higher than those in the control group after therapy. The leakage rates of bone cement (intervertebral disc leakage, paravertebral vein leakage, paravertebral soft tissue leakage) of patients in the observation group were notably lower than those in the control group after therapy (P=0.029).

CONCLUSION

Bone filling mesh bag technology offers significant improvements in Cobb angle and vertebral height for treating elderly patients with osteoporotic thoracic vertebral compression fractures, and reduced the leakage rate of bone cement. This technique achieves comparable therapeutic outcomes to curved vertebroplasty.

Ultrasound-dependent kinetics of bone mineralization

Bone Mineral Density (BMD) is an important parameter in the development of orthopedic fracture-healing methods. A recent article (Inoue, S., et al. Bone. 2023, 177, 116916) investigated the use of higher intensity ultrasound to promote murine bone formation by measuring BMD levels. In this work, we present the numerical values of BMD, which show sigmoid kinetics and hyperbolic asymptotic increase with the application of higher intensity ultrasound. Our analysis may provide a foundation for the understanding and application of ultrasound to the human body.

Establishing a nomogram to predict refracture after percutaneous kyphoplasty by logistic regression

Introduction

Several studies have examined the risk factors for post-percutaneous kyphoplasty (PKP) refractures and developed many clinical prognostic models. However, no prior research exists using the Random Forest (RF) model, a favored tool for model development, to predict the occurrence of new vertebral compression fractures (NVCFs). Therefore, this study aimed to investigate the risk factors for the occurrence of post-PKP fractures, compare the predictive performance of logistic regression and RF models in forecasting post-PKP fractures, and visualize the logistic regression model.

Methods

We collected clinical data from 349 patients who underwent PKP treatment at our institution from January 2018 to December 2021. Lasso regression was employed to select risk factors associated with the occurrence of NVCFs. Subsequently, logistic regression and RF models were established, and their predictive capabilities were compared. Finally, a nomogram was created.

Results

The variables selected using Lasso regression, including bone density, cement distribution, vertebral fracture location, preoperative vertebral height, and vertebral height restoration rate, were included in both the logistic regression and RF models. The area under the curves of the logistic regression and RF models were 0.868 and 0.786, respectively, in the training set and 0.786 and 0.599, respectively, in the validation set. Furthermore, the calibration curve of the logistic regression model also outperformed that of the RF model.

Conclusion

The logistic regression model provided better predictive capabilities for identifying patients at risk for post-PKP vertebral fractures than the RF model.

A nomogram for predicting the risk of new vertebral compression fracture after percutaneous kyphoplasty

BACKGROUND

New vertebral compression fractures (NVCFs) are common adverse events in percutaneous kyphoplasty (PKP). The present study aimed to investigate the risk factors for NVCFs in patients after PKP and to construct a nomogram for the prediction of the risk of re-fracture.

METHODS

We retrospectively analyzed the medical records of patients after PKP surgery between January 2017 and December 2020. Patients were divided into an NVCF group (n = 225) and a control group (n = 94) based on the presence or absence of NVCFs, respectively, at follow-up within 2 years after surgery. Lasso regression was used to screen for risk factors for re-fracture. Based on the results, a Lasso-logistic regression model was developed, and its prediction performance was evaluated using receiver operating characteristic curves, calibration, and decision curve analysis. The model was visualized, and a nomogram was constructed.

RESULTS

A total of eight potential predictors were obtained from Lasso screening. Advanced age, low body mass index, low bone mineral density, lack of anti-osteoporosis treatment, low preoperative vertebral body height, vertebral body height recovery ≥ 2, cement leakage, and shape D (lack of simultaneous contact of bone cement with the upper and lower plates) were included in the logistic regression model.

CONCLUSIONS

A nomogram for predicting postoperative NVCF in PKP was developed and validated. This model can be used for rational assessment of the magnitude of the risk of developing NVCFs after PKP, and can help orthopedic surgeons make clinical decisions aimed at reducing the occurrence of NVCFs.

Bone microarchitecture and metabolism in elderly male patients with signs of intravertebral cleft on MRI

OBJECTIVES

Intravertebral cleft (IVC) is a common but not unique imaging manifestation in Kümmell's disease. To date, great controversy exists regarding the specific mechanisms of IVC. In this study, we aimed to investigate the characteristics of microarchitecture and metabolism in patients with IVC and to analyse the correlations between degree of vertebral collapse and risk factors.

METHODS

A total of 79 elderly men were included in this study. We divided all patients into two groups: the IVC group (30 patients) and the non-IVC group (49 patients). We compared the differences in microarchitecture and bone turnover marker (BTM) serum concentrations between the groups and analysed risk factors affecting vertebral collapse by using the Mann-Whitney U test and Spearman's correlation test.

RESULTS

Quantitative analysis of the microarchitecture showed higher content of necrotic bone (p < 0.001) and lower content of lamellar bone (p < 0.001) in the IVC group. Analysis of BTMs identified lower concentration of N-terminal propeptide of type I collagen (PINP, p = 0.002) and higher concentration of β-isomerized C-terminal telopeptide (β-CTX, p < 0.001) in the IVC group. The correlation analysis showed that lamellar bone content (p < 0.001) and spine T-score (p = 0.011) were significantly correlated with the degree of vertebral collapse.

CONCLUSIONS

IVC is a radiological feature of excessive bone resorption by higher activities of osteoclasts and decreased bone remodelling ability by lower activities of osteoblasts. Histomorphological feature in patients with IVC is delayed callus mineralisation, which may increase the risk of vertebral collapse.

KEY POINTS

• A key histomorphological feature in patients with IVC is delayed callus mineralisation, which may aggravate the degree of vertebral collapse. • We investigated bone metabolism in patients with IVC to evaluate the activities of osteoclasts and osteoblasts directly. • We propose a novel hypothesis for the pathogenesis of IVC: bone resorption by higher activity of osteoclasts and decreased callus mineralisation ability by lower activity of osteoblasts are the main mechanisms leading to IVC.