Subsequent vertebral fracture after vertebroplasty: incidence and analysis of risk factors

The clinical effect of different vertebral body height restoration rates after percutaneous kyphoplasty for osteoporotic vertebral compression fractures

OBJECTIVE

This study aimed to evaluate the clinical effect of different vertebral body heights restoration rate after percutaneous kyphoplasty (PKP) for the treatment of osteoporotic vertebral compression fractures (OVCF).

METHODS

The patients were divided into two groups according to the height restoration rate of the anterior edge of the vertebral body fracture after PKP operation using X-Ray imaging. The group A was below 80%, and the group B was above 80%. Clinical preoperative and postoperative efficacy (1st day, 1st month, 6th month, and 12th month after surgery) were evaluated according to VAS, Oswestry Disability Index(ODI), Quality of Life Questionnaire of the European Foundation for Osteoporosis(QUALEFFO), and Back Pain Life Disorder Questionnaire(RQD). Simultaneously, the preoperative and postoperative local Cobb angles and changes in the injured vertebrae in the two groups were calculated and analyzed.

RESULTS

The postoperative Cobb angle in group A was significantly higher than that in group B. The correction rate in group B was significantly better than that in group A. The VAS, ODI, QUALEFFO, and RQD scores of group B patients were significantly lower than those of patients in group A at each follow-up time point. The correlation coefficients of vertebral body height restoration rate and VAS, ODI, QUALEFFO, and RQD scores at the last follow-up were - 0.607 (P < 0.01), -0.625 (P < 0.01), -0.696 (P < 0.01), and - 0.662 (P < 0.01), respectively.

CONCLUSIONS

The results of the correlation analysis between the vertebral body height restoration rate and the above clinical efficacy scores show that increasing the vertebral body anterior height restoration rate is beneficial for pain relief and improves the clinical efficacy of patients. Simultaneously, improving the height restoration rate of the anterior edge of the vertebral body and restoring the normal spinal structure is beneficial for reducing the incidence of refracture of the adjacent vertebral body.

Incidence and risk factors of subsequent vertebral fracture following percutaneous vertebral augmentation in postmenopausal women

PURPOSE

Subsequent vertebral fracture (SVF) is a severe advent event of percutaneous vertebral augmentation (PVA). However, the incidence and risk factors of SVF following PVA for OVCF in postmenopausal women remain unclear. This research aims to investigative the incidence and risk factors of SVF after PVA for OVCF in postmenopausal women.

METHODS

Women who underwent initial PVA for OVCF between August 2019 and December 2021 were reviewed. Univariate logistic regression analysis was performed to identify possible risk factors of SVF, and independent risk factors were determined by multivariate logistic regression.

RESULTS

A total of 682 women after menopause were enrolled in the study. Of these women, 100 cases had an SVF after PVA, with the incidence of 14.66%. Univariate logistic regression analysis demonstrated that age (p = 0.001), body mass index (BMI) (p < 0.001), steroid use (p = 0.008), history of previous vertebral fracture (p < 0.001), multiple vertebral fracture (p = 0.033), postoperative wedge angle (p = 0.003), and HU value (p < 0.001) were significantly correlated with SVF following PVA. Furthermore, BMI (OR [95%CI] = 0.892 [0.825 - 0.965]; p = 0.004), steroid use (OR [95%CI] = 3.029 [1.211 - 7.574]; p = 0.018), history of previous vertebral fracture (OR [95%CI] = 1.898 [1.148 - 3.139]; p = 0.013), postoperative wedge angle (OR [95%CI] = 1.036 [1.004 - 1.070]; p = 0.028), and HU value (OR [95%CI] = 0.980 [0.971 - 0.990]; p < 0.001) were identified as independent risk factors of SVF after PVA by multivariate logistic regression analysis.

CONCLUSIONS

The incidence of SVF following PVA for OVCF in postmenopausal women was 14.66%. BMI, steroid use, history of previous vertebral fracture, postoperative wedge angle, and HU value were independent risk factors of SVF after PVA for OVCF in postmenopausal women.

Analysis of adjacent vertebral fracture after percutaneous vertebroplasty: do radiological or surgical features matter?

PURPOSE

To report the incidence and risk factors of adjacent vertebral fracture (AVF) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs). We focused to investigate effect of radiological or surgical features on AVF.

METHODS

All patients with OVCFs who were treated with PVP between January 2016 and December 2019 were retrospectively reviewed. Patients were followed up at least 12 months after procedure according to treatment protocol. AVF was defined as postoperatively recurrent intractable back pain and subsequently presence of fracture on magnetic resonance imaging (MRI) in adjacent levels. Clinical, radiological, and surgical factors potentially affecting occurrence of AVF were recorded and analyzed using univariate and multivariate analysis.

RESULTS

Totally, 1077 patients with 1077 fractured vertebrae who underwent PVP were enrolled in the study, after inclusion and exclusion criteria were met. Mean follow-up time was 24.3 ± 11.9 months (range, 12-59 months). AVF was identified in 98 (9.1%) patients. Univariate analysis showed that seven significant factors related to AVF were older age, non-traumatic fracture, cortical disruption on anterior wall, cortical disruption on lateral wall, basivertebral foramen, type-B leakage and type-C leakage. In multivariate analysis, two clinical factors, older age (P = 0.031) and non-traumatic fracture (P = 0.002), were significantly associated with AVF. However, any radiological or surgical factor did not reach significance in final model analysis.

CONCLUSIONS

Incidence of AVF after PVP in patients with OVCFs was 9.1% (98/1077). Older age and non-traumatic fracture were two clinical risk factors for AVF. Neither radiological nor surgical feature was significantly correlated with AVF.

Risk Factors for New Adjacent and Remote Vertebral Fracture After Percutaneous Vertebroplasty

OBJECTIVE

To analyze the risk factors of new adjacent vertebral fractures (AVF) and remote vertebral fractures (RVF) after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs).

METHODS

Patients who underwent additional PVP for new OVCFs were enrolled. In addition, we set a 1:1 age-, sex-, surgical segment-, and surgical date-matched control group, in which patients underwent PVP without new OVCFs. Data on body mass index, occurrence time of second PVP, vertebral computed tomography (CT) Hounsfield Unit (HU) at the fracture adjacent segment, and RVF segment were collected.

RESULTS

A total of 44 patients who underwent additional PVP for new OVCFs at our hospital were included. AVF occurred significantly earlier than RVF (13.5 ± 14.1 vs. 30.4 ± 20.1 months, P = 0.007). Compared to the control group, the AVF segment CT HU was significantly lower in patients with AVF (28.7 ± 16.7 vs. 61.3 ± 14.7, P = 0.000), while there was no significant difference between patients with RVF and control group including both adjacent and RVF segment CT HU. Receiver operating characteristic curves identified a cutoff value of 43 for using adjacent segment CT HU to differentiate patients with AVF from controls, with a sensitivity of 80% and a specificity of 88.9%.

CONCLUSIONS

Our study showed that the risk factors for AVF and RVF after PVP surgery were different. The occurrence of AVF was earlier and associated with low adjacent segment CT HU values, whereas the preoperative CT HU in both adjacent and RVF segments was not found to be associated with RVF.

Robot-assisted percutaneous vertebroplasty for osteoporotic vertebral compression fracture treatment and risk factor screening for postoperative refracture

Osteoporotic vertebral compression fracture (OVCF) is a serious complication of osteoporosis, and percutaneous vertebroplasty (PVP) is a major therapeutic method for OVCF. This study aimed to evaluate the clinical efficacy and postoperative complications of robot-assisted targeted PVP for the treatment of OVCF. The data from 202 OVCF patients were analyzed in this study, including 72 cases received traditional PVP (PVP group), 68 cases received robot-assisted PVP (R-PVP group), and 62 cases underwent robot-assisted PVP combined with targeted plugging (R-PVP + TP group). The fluoroscopic exposure conditions, operative duration, lengths of stay, postoperative bone cement leakage, refracture, Visual Analog Scale (VAS) score, and Oswestry Disability Index (ODI) score were obtained and compared between the three groups. The Kaplan-Meier method and logistic regression model were adopted to screen the risk factors related with postoperative refracture. R-PVP and R-PVP + TP group had significantly reduced fluoroscopic frequency and radiation dose, and reduced cement leakage compared with PVP group. R-PVP + TP not only showed more obvious advantages in these aspects, but also had a lower probability of postoperative refracture. In addition, BMD, fracture vertebral distribution, cement leakage, and surgery methods were independent related with refracture. All the results demonstrated robot assistance could improve the application of PVP in the treatment of OVCF, and robot-assisted PVP combined with targeted plugging showed significantly reduced fluoroscopic exposure, bone cement leakage, and rate of postoperative refracture. BMD, fracture vertebral distribution, cement leakage, and operation methods were identified as four risk factors for the onset of refracture after PVP.

A Toolbox of Bone Consolidation for the Interventional Radiologist

Bone consolidation is increasingly used in the treatment of both benign and malignant bone conditions. Percutaneous vertebroplasty, for example, has been shown to be useful in vertebral compression fractures in the VAPOUR trial which showed its superiority to placebo for pain reduction in the treatment of acute vertebral compressive fractures. Further tools have since been developed, such as kyphoplasty, spinal implants, and even developments in bone cements itself in attempt to improve outcome, such as chemotherapy-loaded cement or cement replacements such as radio-opaque silicon polymer. More importantly, bone fixation and its combination with cement have been increasingly performed to improve outcome. Interventional radiologists must first know the tools available, before they can best plan for their patients. This review article will focus on the tool box available for the modern interventional radiologist.

Clinical outcomes with second injection after insufficient bone cement distribution in unilateral kyphoplasty for osteoporotic vertebral compressive fracture: a cohort retrospective study

BACKGROUND

Bone cement distribution is an important factor affecting pain relief and long-term prognosis of osteoporotic vertebral compression fracture (OVCF) treated with vertebral augmentation. Unilateral percutaneous kyphoplasty (PKP) is the most common procedure, and insufficient bone cement distribution is more common than bilateral PKP. However, effective remedies are remain lack. In this study, sufficient cement distribution was achieved by adjusting the working channel followed by second cement injection as a remedy in cases with insufficient cement distribution, and the purpose was to evaluate the clinical outcomes by a retrospective cohort study.

METHODS

From July 1, 2017 to July 31, 2020, OVCF patients treated with unilateral PKP were included in this retrospective cohort study. According to the bone cement distribution (insufficient cement distribution was confirmed when the cement did not exceed the mid line of the vertebral body in frontal film or/and the cement did not contact the upper/lower vertebral endplates in the lateral film.) and whether second injection was performed during surgery, the patients were divided into three groups. Insufficient group: patients with insufficient cement distribution confirmed by fluoroscopy or postoperative x-ray. Second injection group: patients with insufficient cement distribution was found during the procedure, and second injection was performed to improve the cement distribution.

CONTROL GROUP

patients with sufficient cement distribution in one injection. The Primary outcome was cemented vertebrae re-collapse rate. The secondary outcomes included operative time, radiation exposure, cement leakage rate, VAS, ODI, and adjacent vertebral fracture rate.

RESULTS

There are 34 cases in insufficient group, 45 cases in second injection group, and 241 cases in control group. There was no significant difference in baseline data and follow-up time among the three groups.

PRIMARY OUTCOME

The injured vertebrae re-collapse rate of insufficient group was significantly higher than that of second injection group (42.22% vs 20.59%, P = 0.000) and control group (42.22% vs. 18.26%, P = 0.000). Kaplan-Meier survival analysis showed that there was no significant difference in the survival time between second injection group and control group (P = 0.741, Log-rank test), both of which were significant less than that in insufficient group (P = 0.032 and 0.000, respectively).

SECONDARY OUTCOMES

There was no significant difference in VAS score and ODI after operation between second injection group and control group, both of which were superior to those in insufficient group (P = 0.000). At the final follow-up, there was no significant difference in VAS and ODI among the three groups (P > 0.05). The operation time of second injection group was significantly higher than that of insufficient group (53.41 ± 8.85 vs 44.18 ± 7.41, P = 0.000) and control group (53.41 ± 8.85 vs 44.28 ± 7.22, P = 0.000). The radiation exposure of the second injection group was significantly higher than that of insufficient group (40.09 ± 8.39 vs 30.38 ± 6.87, P = 0.000) and control group (40.09 ± 8.39 vs 31.31 ± 6.49, P = 0.000). The cement leakage rate of second injection group (20.59%) was comparable with that of insufficient group (24.44%) and control group (21.26%) (P = 0.877). The length of hospital stay of the second injection group (4.38 ± 1.72) was comparable with that of insufficient group (4.18 ± 1.60) and control group (4.52 ± 1.46) (P = 0.431).

CONCLUSIONS

When cement distribution is insufficient during unilateral PKP, second injection may relieve early pain, reduce the incidence of cemented vertebral re-collapse and adjacent vertebral fracture, without increasing the cement leakage rate, although this procedure may increase the operation time and radiation exposure.

Development of a nomogram model for prediction of new adjacent vertebral compression fractures after vertebroplasty

BACKGROUND

Vertebroplasty is the main minimally invasive operation for osteoporotic vertebral compression fracture (OVCF), which has the advantages of rapid pain relief and shorter recovery time. However, new adjacent vertebral compression fracture (AVCF) occurs frequently after vertebroplasty. The purpose of this study was to investigate the risk factors of AVCF and establish a clinical prediction model.

METHODS

We retrospectively collected the clinical data of patients who underwent vertebroplasty in our hospital from June 2018 to December 2019. The patients were divided into a non-refracture group (289 cases) and a refracture group (43 cases) according to the occurrence of AVCF. The independent predictive factors for postoperative new AVCF were determined by univariate analysis, least absolute shrinkage and selection operator (LASSO) logistic regression, and multivariable logistic regression analysis. A nomogram clinical prediction model was established based on relevant risk factors, and the receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA) were used to evaluate the prediction effect and clinical value of the model. After internal validation, patients who underwent vertebroplasty in our hospital from January 2020 to December 2020, including a non-refracture group (156 cases) and a refracture group (21 cases), were included as the validation cohort to evaluate the prediction model again.

RESULTS

Three independent risk factors of low bone mass density (BMD), leakage of bone cement and "O" shaped distribution of bone cement were screened out by LASSO regression and logistic regression analysis. The area under the curve (AUC) of the model in the training cohort and the validation cohort was 0.848 (95%CI: 0.786-0.909) and 0.867 (95%CI: 0.796-0.939), respectively, showing good predictive ability. The calibration curves showed the correlation between prediction and actual status. The DCA showed that the prediction model was clinically useful within the whole threshold range.

CONCLUSION

Low BMD, leakage of bone cement and "O" shaped distribution of bone cement are independent risk factors for AVCF after vertebroplasty. The nomogram prediction model has good predictive ability and clinical benefit.

Unsubtracted Roadmap Technique for Preventing Cement Leakage During Percutaneous Vertebroplasty: A Retrospective Cohort Study

OBJECTIVE

To determine the effectiveness of the unsubtracted roadmap technique (USRT) for decreasing cement leakage (CL) during percutaneous vertebroplasty (PVP).

METHODS

In this retrospective cohort study, patients who underwent PVP between January and November 2018 were included. Patients were divided into the unsubtracted roadmap (UR) (n = 20) and conventional venography (CV) (n = 22) groups. USRT was performed before cement injection in the UR group. Computed tomography was performed on the first day after PVP in both groups to assess the CL. The vertebral height restoration rate was confirmed by radiography before and after the procedure. The CL location was classified as basivertebral vein (type B), segmental vein (type S), or cortical defect (type C). Visual analog scale and Oswestry Disability Index scores before and after surgery were calculated to confirm clinical outcomes.

RESULTS

Based on the computed tomography images, CL occurred in 7 (34.78%) and 15 (63.64%) cases in the UR and CV groups, respectively. Number of CL type B, S, and C in the UR and CV groups were 2 and 6, 3 and 6, and 2 and 3, respectively. The injected cement volume was not significantly different between the UR (4.86 mL) and the CV (4.75 mL) groups (P = 0.450). Regarding vertebral body height restoration (P = 0.856) and clinical outcomes, there were no significant differences between both groups. Radiation exposure was significantly less in the UR group (P = 0.019).

CONCLUSIONS

USRT is an effective method for reducing CL and radiation exposure during PVP.

Investigation of preoperative asymptomatic bacteriuria as a risk factor for postvertebroplasty infection

BACKGROUND

Postvertebroplasty infection (PVI) is a catastrophic complication after vertebroplasty (VP). Although the urinary tract has been considered as a source of infectious pathogens, whether asymptomatic bacteriuria (ASB) is a risk factors for PVI remains unknown.

METHODS

This retrospective study included 716 patients (207 males; 509 females) treated with VP for osteoporotic vertebral fractures in a single medical center between May 2015 and December 2019. Clinical symptoms, urinalysis results, and culture data were collected preoperatively to identify patients with ASB. The primary outcome was PVI at the index level during follow-up. Demographic data and laboratory test results were compared between the PVI and non-PVI groups.

RESULTS

The mean age of the cohort was 78.6 ± 9.6 (range, 63-106). The prevalence of ASB was 14.1%, with female predominance (63.4%). The overall PVI rate was 1.26% (9/716). The PVI group had more patients with ASB (4/9, 44.4%) than did the non-PVI group (97/707, 13.7%) (p = 0.027). The rate of ASB treatment was similar between the PVI and non-PVI groups (25% vs. 23.7%, respectively). No case of PVI was caused by the urine culture pathogen. Multivariate analysis identified the following risk factors for PVI: ASB (odds ratio [OR], 5.61; 95% CI, 1.14-27.66; p = 0.034), smoking (OR, 16.26; 95% CI, 2.58-102.65; p = 0.003), and malignancy (OR 7.27; 95% CI, 1.31-40.31; p = 0.023).

CONCLUSION

ASB was not uncommon among patients admitted for VP and should be considered a marker of relatively poor host immunity. Preoperative ASB, a history of malignancy, and smoking were identified as significant risk factors for PVI.

Correlation analysis of larger side bone cement volume/vertebral body volume ratio with adjacent vertebral compression fractures during vertebroplasty

OBJECTIVE

To investigate the correlation analysis of larger side bone cement volume/vertebral body volume ratio (LSBCV/VBV%) with adjacent vertebral compression fracture (AVCF) in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fracture (OVCF).

METHODS

A retrospective analysis of 245 OVCF patients who underwent PVP treatment from February 2017 to February 2021, including 85 males and 160 females. The age ranged from 60 to 92 years, with a mean of (70.72 ± 7.03) years. According to whether AVCF occurred after surgery, they were divided into 38 cases in the AVCF group (fracture group) and 207 cases in the no AVCF group (non-fracture group). The correlation between gender, age, bone mineral density (BMD), body mass index (BMI), thoracolumbar segment fracture, bone cement disc leakage, LSBCV, bone cement volume (BCV), VBV, LSBCV/VBV ratio (LSBCV/VBV%), and BCV/VBV% and AVCF were analyzed in both groups. Risk factors for AVCF after PVP were analyzed by multifactorial logistic regression, and then the receiver operating characteristic curves (ROC curves) were plotted to identify the critical value of LSBCV/VBV%.

RESULTS

38 patients (15.5%) developed AVCF postoperatively. Univariate analysis showed that BMD, bone cement disc leakage, LSBCV, and LSBCV/VBV% were risk factors for AVCF after PVP (P<0.05), while gender, age, BMI, thoracolumbar segment fracture, BCV, VBV, and BCV/VBV% were not significantly different in both groups (P>0.05). Multifactorial logistic regression analysis revealed that BMD, bone cement disc leakage, and LSBCV/VBV% were independent risk factors for AVCF after PVP (P<0.05). According to the ROC curve, the LSBCV/VBV% had an area under the curve of 71.6%, a sensitivity and specificity of 89.5% and 51.7%, respectively, and a critical value of 13.82%.

CONCLUSION

BMD, bone cement disc leakage and LSBCV/VBV% are independent risk factors for AVCF after PVP. With LSBCV/VBV at 13.82%, the incidence of AVCF significantly increased.

Biomechanical CT-computed bone strength predicts the risk of subsequent vertebral fracture

Following primary fractures and percutaneous kyphoplasty (PKP), patients have a high risk of incurring a subsequent vertebral fracture (SVF). Given that SVF is a consequence of mechanical deterioration of the vertebra, we sought to examine whether vertebral strength derived from QCT-based finite element analysis (i.e., BCT) can predict the risk of SVF. Sixty-six patients who underwent PKP were categorized into two groups: control or non-SVF group (age: 70 ± 7 years; n = 40) and SVF group (age: 69 ± 8 years; n = 26). BCT was performed on L4 or L3 vertebrae to noninvasively measure vertebral strength. Vertebral strength was also estimated based upon the geometry and material properties of the vertebra. Additionally, trabecular volumetric bone mineral density (vBMD) and L1 Hounsfield unit (HU) were measured. t-Test, χ² test or Mann Whitney U test were used to compare differences in these parameters between the two groups. The predictive abilities of BCT strength and other measured parameters were evaluated using the receiver operating characteristic (ROC) analysis. Results showed no significant difference in either vBMD or L1 HU between the control and SVF groups (p > 0.05), whereas BCT-computed and estimated vertebral strength values were significantly reduced by 33 % and 24 % for the SVF group relative to the non-SVF group, respectively. ROC curve indicated that BCT strength had the largest area under the curve, compared to other parameters. These results suggest that BCT-computed vertebral strength may serve as a surrogate for assessing risk of SVF.

Recompression of Augmented Vertebrae after Balloon Kyphoplasty Is a Risk of Adjacent Vertebral Fracture

Introduction

This study aimed to identify factors associated with adjacent vertebral fracture (AVF) incidence after balloon kyphoplasty (BKP).

Methods

To perform the analyses, 133 vertebrae of 128 patients who underwent BKP for osteoporotic vertebral compression fracture were retrospectively investigated. According to the presence of AVF throughout a 1-year period following BKP, patients were divided into AVF (n = 22) and non-AVF (n = 111) groups. The groups were compared with respect to pre- and postoperative parameters, including the incidence of recompression of augmented vertebrae (RAV). RAV was defined as a decrease in anterior vertebral body height of at least 5 mm within the 3 months that followed BKP. To identify factors associated with AVF incidence, univariate and multivariate analyses were performed.

Results

The univariate analysis revealed that the AVF group had a lower cement augmentation ratio, greater preoperative wedge angle, lower preoperative vertebral body height, lower postoperative vertebral body height 3 months post-BKP, and a greater change in vertebral body height and rate of RAV than the non-AVF group. Multivariate analysis revealed that low preoperative vertebral body height and RAV occurrence were associated with AVF incidence.

Conclusions

To the best of our knowledge, this study is the first to indicate that RAV is a risk factor for AVF. Study findings indicate that the incidence of AVF can be decreased if RAV development is avoided.

IL-6 and Leptin Are Potential Biomarkers for Osteoporotic Fracture Risk Assessment and Prediction of Postmenopausal Women with Low Bone Mass: A Follow-Up Study Using a Regional Sample Cohort

Osteoporotic fracture, a major complication which is known as the outcome postmenopausal osteoporosis, seriously threatens the health of postmenopausal women. At present, the traditional osteoporotic fracture prediction methods are characterized by inconvenient application and time-consuming statistical results, while predictive serum biomarkers can make up for this shortcoming. Accurate and advanced risk prediction of osteoporotic fracture is meaningful to early prevention and intervention, effectively avoiding the risk of this disease and the secondary fracture in the surgical treatment. In this study, based on the BEYOND cohort, a 2-year follow-up study was conducted after subjects participated to survey if OF occurred. Independent sample t-test and Mann–Whitney U-test were used to analyze the differences of bone metabolism biomarkers between the OF and non-OF group. Cox proportional hazard model was used to screen the potential biomarkers might be used to predict OF risk. ROC curves and AUCs were used to analyze the predictive accuracy, and the Delong's test was used to compare the differences between the AUCs. 15 postmenopausal women with low bone mass and OF were found, and other 60 subjects without OF were matched with 1 : 4, age, and BMI classification as control group. The serum IL-6 (OR = 1.139, 95%CI = 1.058 − 1.226) and leptin (OR = 0.921, 95%CI = 0.848 − 1.000) were found as OF risk predictive biomarkers for postmenopausal women with low bone mass with high accuracy (IL − 6 = 0.871) (leptin = 0.813) and accuracy enhanced when they were combined (AUC = 0.898). The results of Delong's test showed that the difference of AUC between leptin and IL-6&Leptin was meaningful (P = 0.024) but meaningless between IL-6 and leptin (P = 0.436), IL-6 and IL-6&Leptin (P = 0.606). To sum up, IL-6 and leptin are the predictive biomarkers of OF for postmenopausal women with low bone mass. The IL-6 can improve the prediction accuracy of leptin (P = 0.024), but not vice versa (P = 0.606). Trial Information. Registered on the Chinese Clinical Trial Registry already. (Registration Number: ChiCTR-SOC-17013090).

Assessment of clinical, imaging, surgical risk factors for subsequent fracture following vertebral augmentation in osteoporotic patients

INTRODUCTION

Currently, the risk factors for subsequent fracture following vertebral augmentation remain incomplete and controversial. To provide clinicians with accurate information for developing a preventive strategy, we carried out a comprehensive evaluation of previously controversial and unexplored risk factors.

METHODS

We retrospectively reviewed patients with osteoporotic vertebral compression fracture in lumbar spine who received vertebral augmentation between January 2019 and December 2020. Based on whether refracture occurred, patients were assigned to refracture and non-refracture group. The clinical characteristics, imaging parameters (severity of vertebral compression, spinal sagittal alignment, degeneration of paraspinal muscles), and surgical indicators (cement distribution and leakage, correction of spinal sagittal alignment) were collected and analyzed.

RESULTS

There were 128 patients and 16 patients in non-refracture and refracture group. The incidence of previous fracture, multiple fractures, and cement leakage were notably higher, relative cross-sectional area of psoas (r-CSA_PS) was significantly smaller, CSA ratio, fatty infiltration of erector spinae plus multifidus (FI_ES+MF), FI_PS, postoperative lumbar lordosis (post-LL), correction of body angel (BA), and LL were significantly greater in refracture group. Binary logistic regression analysis revealed previous fracture, cement leakage, post-LL, and correction of BA were independent risk factors. According to the ROC curve, correction of BA showed the highest prediction accuracy, and the critical value was 3.45°.

CONCLUSIONS

The occurrence of subsequent fracture might be the consequence of multiple factors. Previous fracture, cement leakage, post-LL, and correction of BA were identified as independent risk factors. Furthermore, the correction of BA should not exceed 3.45°, especially in patients with risk factors.

The Effects of Bone Cement Volume in Percutaneous Vertebroplasty for Thoracolumbar Junction Vertebral Compression Fractures: A Clinical Comparative Study

We compared the outcomes of patients treated with different volumes of polymethyl methacrylate bone cement during percutaneous vertebroplasty (PVP) for thoracolumbar vertebral compression fractures. We performed a comparative, retrospective study of 316 patients who underwent PVP for a single-level thoracolumbar vertebral compression fracture. Patients were divided into two groups: group A (≤5 mL; n = 146) and group B (>5 mL; n = 170). The visual analogue scale (VAS) for pain and the Roland-Morris Disability Questionnaire (RDQ) scores were compared between the two groups at 1 week and at 1, 6, 12, and 24 months after PVP. The incidence of cement leakage into the intervertebral discs was evaluated by a postoperative lateral radiograph assessment. Patients were evaluated for new fractures 1 and 2 years after PVP or when new fractures were suspected. Among the 316 patients enrolled, 245 completed the clinical research. No difference between groups A and B in terms of the VAS, RDQ, and rate of complications at all time points after surgery was observed. The presence of intervertebral disc leakage was a relative risk (RR) for subsequent total vertebral fracture (RR, 6.42; 95% confidence interval (CI), 2.72-14.19; P < 0.0001) and adjacent vertebral fracture (RR, 8.03; 95% CI, 2.74-23.54; P = 0.0001). A high volume of bone cement may increase the rate of subsequent total and adjacent vertebral fractures. However, the occurrence of intervertebral disc leakage is the principal risk factor for these negative outcomes of PVP.

Subsequent fractures after vertebroplasty in osteoporotic vertebral fractures: a meta-analysis

Percutaneous vertebroplasty (VP) provides substantial benefit to patients with painful osteoporotic vertebral compression fractures (OVCF). However, the reoccurrence of vertebral fracture after VP is a major concern. The purpose of this study is to conduct a meta-analysis on the incidence of subsequent fractures after VP in patients with OVCF. PubMed and EMBASE were searched. In addition, we scrutinized the reference list of all relevant articles to supplement the database search. We included original articles reporting on new fracture rates after VP in OVCF patients. Subsequent fracture rates were pooled across studies using a random-effects meta-analysis. Thirty-nine studies with a total of 8047 participants from 12 countries were included in this meta-analysis. Patients' age ranged from 64.2 to 94.6 years (reported by 31 studies). The median follow-up was 21 months (36 studies). Pooled estimate for subsequent fractures after VP was 23.4% (95% CI, 19.8-27.2%; I² = 93.0%, p < 0.01). New fractures after VP in 54.6% of cases occurred in the vertebral bodies adjacent to the treated vertebra (95% CI, 49.0-60.1%; I² = 66.0%, p < 0.01). A significant proportion of patients undergoing VP for OVCF experience new fractures after treatment, most of which are developed in the vertebral bodies adjacent to the treated vertebra.

Cumulative Incidence and Factors Associated with Subsequent Vertebral Compression Fractures: A Nationwide Population-based Study

OBJECTIVE

Patients who experience vertebral compression fractures are vulnerable to subsequent vertebral compression fractures (SVCFs). The purpose of this nationwide population-based study was to determine the age-specific cumulative incidence and factors associated with SVCFs in South Korea.

METHODS

Diagnostic codes, medical costs, and comorbid diseases in patients who had a vertebral compression fracture in 2011 and 2012 were collected from the National Health Insurance Service database of South Korea from 2007 to 2018. Demographic data, mortality rate, medical cost, and frequency of vertebroplasty or kyphoplasty were compared between patients with an initial fracture (IF) and those with a subsequent fracture (SF).

RESULTS

The cumulative incidence of SVCFs over 4 years was 24.4% and increased rapidly within a few months after the IF. In 2011, SVCFs occurred in 17,004 patients, and the incidence rate per 100,000 people was 113.6 (84.9 in men vs. 138.5 in women). The odds ratio (OR) of SVCFs in units of 10 years was the highest in women in their 60s, at 2.89. However, in men in their 70s, the OR was the highest, at 2.51. The rates of vertebroplasty or kyphoplasty, medical expenses, and mortality rate were significantly higher in the SF group than in the IF group (p < 0.01).

CONCLUSION

The age-specific cumulative incidence of SVCFs per 100,000 people was 113.6. SVCFs were more frequent among women, the elderly, and patients who underwent vertebroplasty or kyphoplasty. Women in their 60s or above and men in their 70s or above were at highest risk.

Development and internal validation of a clinical prediction model for acute adjacent vertebral fracture after vertebral augmentation : the AVA score

AIMS

To develop and internally validate a preoperative clinical prediction model for acute adjacent vertebral fracture (AVF) after vertebral augmentation to support preoperative decision-making, named the after vertebral augmentation (AVA) score.

METHODS

In this prognostic study, a multicentre, retrospective single-level vertebral augmentation cohort of 377 patients from six Japanese hospitals was used to derive an AVF prediction model. Backward stepwise selection (p < 0.05) was used to select preoperative clinical and imaging predictors for acute AVF after vertebral augmentation for up to one month, from 14 predictors. We assigned a score to each selected variable based on the regression coefficient and developed the AVA scoring system. We evaluated sensitivity and specificity for each cut-off, area under the curve (AUC), and calibration as diagnostic performance. Internal validation was conducted using bootstrapping to correct the optimism.

RESULTS

Of the 377 patients used for model derivation, 58 (15%) had an acute AVF postoperatively. The following preoperative measures on multivariable analysis were summarized in the five-point AVA score: intravertebral instability (≥ 5 mm), focal kyphosis (≥ 10°), duration of symptoms (≥ 30 days), intravertebral cleft, and previous history of vertebral fracture. Internal validation showed a mean optimism of 0.019 with a corrected AUC of 0.77. A cut-off of ≤ one point was chosen to classify a low risk of AVF, for which only four of 137 patients (3%) had AVF with 92.5% sensitivity and 45.6% specificity. A cut-off of ≥ four points was chosen to classify a high risk of AVF, for which 22 of 38 (58%) had AVF with 41.5% sensitivity and 94.5% specificity.

CONCLUSION

In this study, the AVA score was found to be a simple preoperative method for the identification of patients at low and high risk of postoperative acute AVF. This model could be applied to individual patients and could aid in the decision-making before vertebral augmentation. Cite this article: Bone Joint J 2022;104-B(1):97-102.

What are risk factors for subsequent fracture after vertebral augmentation in patients with thoracolumbar osteoporotic vertebral fractures

Background

Due to its unique mechanical characteristics, the incidence of subsequent fracture after vertebral augmentation is higher in thoracolumbar segment, but the causes have not been fully elucidated. This study aimed to comprehensively explore the potential risk factors for subsequent fracture in this region.

Methods

Patients with osteoporotic vertebral fracture in thoracolumbar segment who received vertebral augmentation from January 2019 to December 2020 were retrospectively reviewed. Patients were divided into refracture group and non-refracture group according to the occurrence of refracture. The clinical information, imaging findings (cement distribution, spine sagittal parameters, degree of paraspinal muscle degeneration) and surgery related indicators of the included patients were collected and compared.

Results

A total of 109 patients were included, 13 patients in refracture group and 96 patients in non-refracture group. Univariate analysis revealed a significantly higher incidence of previous fracture, intravertebral cleft (IVC) and cement leakage, greater fatty infiltration of psoas (FI_PS), fatty infiltration of erector spinae plus multifidus (FI_ES + MF), correction of body angle (BA), BA restoration rate and vertebral height restoration rate in refracture group. Further binary logistic regression analysis demonstrated previous fracture, IVC, FI_PS and BA restoration rate were independent risk factors for subsequent fracture. According to ROC curve analysis, the prediction accuracy of BA restoration rate was the highest (area under the curve was 0.794), and the threshold value was 0.350.

Conclusions

Subsequent fracture might cause by the interplay of multiple risk factors. The previous fracture, IVC, FI_PS and BA restoration rate were identified as independent risk factors. When the BA restoration rate exceeded 0.350, refractures were more likely to occur.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04946-7.

Density and mechanical properties of vertebral trabecular bone-A review

Being able to predict the mechanical properties of vertebrae in patients with osteoporosis and other relevant pathologies is essential to prevent fractures and to develop the most favorable fracture treatments. Furthermore, a reliable prediction is important for developing more patient- and pathology-specific biomaterials. A plethora of studies correlating bone density to mechanical properties has been reported; however, the results are variable, due to a variety of factors, including anatomical site and methodological differences. The aim of this study was to provide a comprehensive literature review on density and mechanical properties of human vertebral trabecular bone as well as relationships found between these properties. A literature search was performed to include studies, which investigated mechanical properties and bone density of trabecular bone. Only studies on vertebral trabecular bone tissue, reporting bone density or mechanical properties, were kept. A large variation in reported vertebral trabecular bone densities, mechanical properties, and relationships between the two was found, as exemplified by values varying between 0.09 and 0.35 g/cm3 for the wet apparent density and from 0.1 to 976 MPa for the elastic modulus. The differences were found to reflect variations in experimental and analytical processes that had been used, including testing protocol and specimen geometry. The variability in the data decreased in studies where bone tissue testing occurred in a standardized manner (eg, the reported differences in average elastic modulus decreased from 400% to 10%). It is important to take this variability into account when analyzing the predictions found in the literature, for example, to calculate fracture risk, and it is recommended to use the models suggested in the present review to reduce data variability.

A study on the relationship between the rate of vertebral body height loss before balloon kyphoplasty and early adjacent vertebral fracture

BACKGROUND

The number of patients with an osteoporotic vertebral compression fracture, which is often accompanied by lower back pain and restrained activities, is growing. Balloon kyphoplasty involves the inflation of a balloon to restore height and reduce kyphotic deformity before stabilization with polymethylmethacrylate. However, there is a great deal of debate about whether balloon kyphoplasty also increases fracture morbidity by either inducing or facilitating subsequent adjacent vertebral fractures.

OBJECTIVE

To evaluate the relationship between the rate of vertebral body height loss before balloon kyphoplasty and the etiology of early adjacent vertebral fracture after augmentation.

METHODS

A total of 59 patients with osteoporotic vertebral compression fractures who underwent kyphoplasty were enrolled. This study defined early adjacent segmental fractures as new fractures occurring within three months after surgery. This study included the rate of vertebral body height loss.

RESULTS

Early adjacent vertebral fractures were diagnosed in nine (15%) of the 59 patients. The patients were divided into two groups, with and without adjacent vertebral fractures. There was no significant difference in terms of age, body mass index, bone mineral density, local kyphotic angle, Cobb's angle, cement volume, cement leakage, and percent height restored between the groups with fractures and without fractures. There was a statistically significant difference between the two groups in the rate of vertebral body height loss. The rate of vertebral body height loss was significantly higher in the fracture group than in the without fracture group.

CONCLUSIONS

A high rate of vertebral body height loss increased the risk of early adjacent vertebral fractures after balloon kyphoplasty.

Improving Secondary Fracture Prevention After Vertebroplasty: Implementation of a Fracture Liaison Service

OBJECTIVE

The aim of our study was to evaluate a multidisciplinary fracture liaison service (FLS) to improve osteoporosis treatment and secondary fracture prevention for patients after vertebroplasty.

METHODS

A retrospective chart review of consecutive vertebroplasty patients from January 2016 to January 2020. FLS began in December 2016 allowing for before-and-after comparison. Statistical analysis included patient demographics and procedure characteristics. Proportion of patients evaluated by the FLS clinic and treatment modification were evaluated. Opt-in versus opt-out referral strategies were compared. Dual energy x-ray absorptiometry scans or vitamin D levels within 3 months before or after vertebroplasty were assessed. Time to event analysis was used to evaluate secondary fracture occurrence.

RESULTS

There were 137 vertebroplasty patients, 39 before FLS and 98 after FLS, included. Only 15% of all patients were already being treated in a bone health clinic. Of those referred and evaluated by the FLS, 73.0% had their osteoporosis treatment modified. Patients evaluated by the FLS were more likely to have a dual energy x-ray absorptiometry scan or a vitamin D level drawn (P < .001 for both). The opt-out referral was more effective with a 75.0% referral rate (P = .71). Secondary fracture of any kind occurred in 23.4% of all patients. Time to event analysis demonstrated a trend toward a reduced risk of secondary spinal fractures in the fracture prevention group with an adjusted hazard ratio of 0.39 (0.13-1.11, 95% confidence interval).

DISCUSSION

A multidisciplinary FLS can be implemented for patients after vertebroplasty to evaluate osteoporotic risk factors and optimize osteoporosis therapy, both of which are important factors in preventing secondary vertebral fractures.

Long-term mechanical properties of a novel low-modulus bone cement for the treatment of osteoporotic vertebral compression fractures

In spite of the success of vertebroplasty (VP) and balloon kyphoplasty (BKP), which are widely used for stabilizing painful vertebral compression fractures, concerns have been raised about use of poly(methyl methacrylate) (PMMA) bone cements for these procedures since the high compressive modulus of elasticity (E) of the cement is thought to be one of the causes of the higher number of adjacent-level vertebral fractures. Therefore, bone cements with E comparable to that of cancellous bone have been proposed. While the quasi-static compressive properties of these so-called "low-modulus" cements have been widely studied, their fatigue performance remains underassessed. The purpose of the present study was to critically compare a commercial bone cement (control cement) and its low-modulus counterpart on the basis of quasi-static compressive strength (CS), E, fatigue limit under compression-compression loading, and release of methyl methacrylate (MMA). At 24 h, mean CS and E of the low-modulus material were 72% and 77% lower than those of the control cement, whereas, at 4 weeks, mean CS and E were 60% and 54% lower, respectively. The fatigue limit of the control cement was estimated to be 43-45 MPa compared to 3-5 MPa for the low-modulus cement. The low-modulus cement showed an initial burst release of MMA after 24 h followed by a plateau, similar to many other commercially available cements, whereas the control cement showed a much lower, stable release from day 1 and up to 1 week. The low-modulus cement may be a promising alternative to currently available PMMA bone cements, with the potential for reducing the incidence of adjacent fractures following VP/BKP.

Association between handgrip strength and subsequent vertebral-fracture risk following percutaneous vertebral augmentation

INTRODUCTION

The aim of this study was to investigate the association between handgrip strength (HGS) and the risk of subsequent vertebral fracture (SVF) after percutaneous vertebral augmentation (PVA).

MATERIALS AND METHODS

A total of 340 patients aged over 50 years with osteoporotic vertebral fracture were enrolled in this 3-year follow-up investigation. HGS was measured with a hand-held dynamometer before PVA. Female patients and male patients were grouped using the HGS threshold recommended by the Asian Working Group for Sarcopenia (AWGS). Kaplan-Meier analysis was used to evaluate SVF-free survival. The hazard ratios (HRs) of HGS for SVF events were estimated with the Cox proportional hazards model.

RESULTS

During the follow-up period, a total of 93 patients (27.4%) experienced SVF. Kaplan-Meier analysis showed that the HGS of female patients < 18.0 kg and male patients < 28 kg was significantly associated with lower SVF-free survival (female patients: p < 0.001, male patients: p = 0.038; log-rank test). Among women, each 1-kg increase in HGS was associated with a 9% lower risk of SVF (HR 0.91, p = 0.035) after adjustment for potential risk factors. Among men, although the associations between low HGS and increased risk of SVF were significant in the crude model (HR 0.79, p < 0.001), this significance disappeared after adjustment for bone mineral density of the femoral neck.

CONCLUSIONS

Low HGS was significantly associated with lower SVF-free survival among elderly patients who underwent single-level PVA for osteoporotic vertebral fracture.

Functional Properties of Low-Modulus PMMA Bone Cements Containing Linoleic Acid

Acrylic bone cements modified with linoleic acid are a promising low-modulus alternative to traditional high-modulus bone cements. However, several key properties remain unexplored, including the effect of autoclave sterilization and the potential use of low-modulus cements in other applications than vertebral augmentation. In this work, we evaluate the effect of sterilization on the structure and stability of linoleic acid, as well as in the handling properties, glass transition temperature, mechanical properties, and screw augmentation potential of low-modulus cement containing the fatty acid. Neither 1H NMR nor SFC-MS/MS analysis showed any detectable differences in autoclaved linoleic acid compared to fresh one. The peak polymerization temperature of the low-modulus cement was much lower (28-30 °C) than that of the high-modulus cement (67 °C), whereas the setting time remained comparable (20-25 min). The Tg of the low-modulus cement was lower (75-78 °C) than that of the high-stiffness cement (103 °C). It was shown that sterilization of linoleic acid by autoclaving did not significantly affect the functional properties of low-modulus PMMA bone cement, making the component suitable for sterile production. Ultimately, the low-modulus cement exhibited handling and mechanical properties that more closely match those of osteoporotic vertebral bone with a screw holding capacity of under 2000 N, making it a promising alternative for use in combination with orthopedic hardware in applications where high-stiffness augmentation materials can result in undesired effects.

Current Concepts in the Management of Osteoporotic Vertebral Fractures: A Narrative Review

Vertebral fractures are the most common type of osteoporotic fracture and can increase morbidity and mortality. To date, the guidelines for managing osteoporotic vertebral fractures (OVFs) are limited in quantity and quality, and there is no gold standard treatment for these fractures. Conservative treatment is considered the primary treatment option for OVFs and includes pain relief through shortterm bed rest, analgesics, antiosteoporotic drugs, exercise, and braces. Studies on vertebral augmentation (VA) including vertebroplasty and kyphoplasty have been widely reported, but there is still debate and controversy regarding the effectiveness of VA when compared with conservative treatment, and the routine use of VA for OVF is not supported by current evidence. Although most OVFs heal well, approximately 15%-35% of patients with unstable fractures, chronic intractable back pain, severely collapsed vertebra (leading to neurological deficits and kyphosis), or chronic pseudarthrosis frequently require surgery. Given that there is no single technique for optimizing surgical outcomes in OVFs, tailored surgical techniques are needed. Surgeons need to pay attention to advances in osteoporotic spinal surgery and should be open to novel thoughts and techniques. Prevention and management of osteoporosis is the key element in reducing the risk of subsequent OVFs. Bisphosphonates and teriparatide are mainstay drugs for improving fracture healing in OVF. The effects of bisphosphonates on fracture healing have not been clinically evaluated. The intermittent administration of teriparatide significantly enhanced spinal fusion and fracture healing and reduced mortality risk. Based on the current literature, there is still a lack of standard management strategies for OVF. There is a need for greater efforts through multimodal approaches including conservative treatment, surgery, osteoporosis treatment, and drugs that promote fracture healing to improve the quality of the guidelines.

Clinical and radiological subsequent fractures after vertebral augmentation for treating osteoporotic vertebral compression fractures: a meta-analysis

PURPOSE

This study aimed to identify all relevant randomized controlled trials (RCT) and prospective non-RCTs to further investigate whether percutaneous vertebral augmentation (PVA) was associated with clinical and radiological subsequent fractures on unoperated levels.

METHODS

We systematically searched PubMed, EMBASE, Cochrane library, Google Scholar, web of science, and ClinicalTrial.gov from the establishment of the database to January 2020. All eligible studies comparing subsequent fractures after PVA with those after conservative treatment (CT) were incorporated. The pooled risk ratio (RR) with its 95% confidence intervals (95% CIs) was used. Heterogeneity, sensitivity, and publication bias analyses were performed.

RESULTS

In all, 32 studies were included in the study: 82/512 patients (16.02%) and 58/433 patients (13.39%) had clinical subsequent fractures in the PVA group and CT group, respectively. No significant differences were observed between the two groups [RR = 1.22, 95% CI 0.70-2.12, P = 0.49]. Further, 175/837 patients (20.91%) in the PVA group and 160/828 patients (19.32%) in the CT group had radiological subsequent fractures. No significant difference was observed between groups [RR = 0.91, 95% CI 0.71-2.12, P = 1.16]. Further, no statistical difference was observed on subgroup analysis between RCTs and non-RCTs or PVP and PKP.

CONCLUSION

Our systematic review revealed that subsequent fractures on unoperated levels were not associated with PVA, regardless of whether they were clinical or radiological subsequent fractures.

Effects of Polymethylmethacrylate Cement Viscosity and Bone Porosity on Cement Leakage and New Vertebral Fractures After Percutaneous Vertebroplasty: A Prospective Study

STUDY DESIGN

A prospective randomized study.

OBJECTIVES

To evaluate the effect of bone cement viscosity as well as of bone porosity on cement leakage during vertebroplasty and to analyze the occurrence of new vertebral fractures after the procedure.

METHODS

Between April 2012 and December 2013, 60 patients suffering from osteoporotic vertebral fractures underwent vertebroplasty. The patients were randomly assigned into 2 equal groups. High-viscosity cement was used in group A, while low-viscosity cement was used in group B. Patients were followed-up for a minimum of 2 years.

RESULTS

Cement leakage occurred in 16 patients in group B (20 vertebral bodies) and in 6 patients in group A (9 vertebral bodies). The difference was statistically significant (χ² = 2.3, P = .01). Lower T-scores were associated with significantly more cement leakage (t = 3.338, P = .002 in group A, and t = 4.329, P = .000 in group B). Patients with a T-score worse than -1.8 had a significantly higher risk of cement leakage if low-viscosity cement was used (χ² = 3.25, P = .05). New vertebral fractures occurred in 14 (23%) patients, after a mean of 6.5 ± 5.5 months, 10 patients in group A and 4 in group B. The difference did not reach the statistical significance level (χ² = 3.354, P = .067). Patients presenting with multiple fractures had a significantly more number of new vertebral fractures (χ² = 7.464, P = .006).

CONCLUSIONS

The clinical outcome of vertebroplasty was not influenced by cement viscosity. However, lower cement viscosity and higher degree of osteoporosis were found to be significant risk factors for cement leakage. Furthermore, the number of vertebral body fractures on presentation was a predictor for the occurrence of new fractures postoperatively.

Development of a scoring system for predicting adjacent vertebral fracture after balloon kyphoplasty

BACKGROUND CONTEXT

The incidence of adjacent vertebral fracture (AVFs) is reported to be 10%-38% after balloon kyphoplasty. However, no reports have established a system for prediction of AVF occurrence.

PURPOSE

To establish a scoring system for predicting AVF occurrence after balloon kyphoplasty for osteoporotic vertebral fractures (OVFs).

DESIGN

A prospective cohort study.

PATIENT SAMPLE

Consecutive elderly patients aged 65 years and older who underwent balloon kyphoplasty for OVFs within 2 months after the onset.

OUTCOME MEASURES

AVF was confirmed by X-ray.

METHODS

From 2015 to 2017, 116 consecutive patients from 10 participating hospitals who underwent balloon kyphoplasty were enrolled in this study. Prior to study enrollment, each patient underwent plain X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the thoracic and lumbar spine. Severity of pain was subjectively assessed using a visual analog scale (VAS) based on the average level of back pain that the patient had experienced in the preceding week. After enrollment, subjects underwent balloon kyphoplasty. Quality of life was evaluated using SF-36. Patients were followed up for at least 6 months.

RESULTS

Of the 116 patients enrolled, 109 patients with all the required data at the time of enrolment and the 6-month follow-up were included in the study. A total of 32 patients (29%) showed AVFs within the 6-month follow-up. No significant differences were observed in each clinical outcome at 6-month follow-up, although higher VAS score for back pain at 1-month follow-up was observed in the AVF group (37.5) than in the non-AVF group (20.8, p<.001). Wedge angle of vertebrae before surgery was greater in the AVF group (21.6°) than in the non-AVF group (15.7°, p<.001). The change in wedge angle between pre- and postsurgery was greater in the AVF group than in the non-AVF group, whereas the change in local kyphosis was not significantly different. The multiple logistic regression model showed increased odds ratio (OR) of thoracic or thoracolumbar spine, old OVF presence, >25° kyphosis before surgery, and >10°correction for AVF. Based on this result, a simple scoring system for predicting AVF occurrence was developed. The total AVF score was calculated as the sum of the individual scores, which varied from 0 to 6. All patients with 5-6 points sustained AVF.

CONCLUSIONS

More severe wedge angle before surgery, correction degree, old OVF presence, and thoracolumbar level were predictive factors for AVF. All patients with AVF risk score of 5 or more showed AVF. This information may aid preoperative risk assessment, informed shared decision-making, and consideration of potential alternative management strategies.

Polymerization kinetics stability, volumetric changes, apatite precipitation, strontium release and fatigue of novel bone composites for vertebroplasty

PURPOSE

The aim was to determine effects of diluent monomer and monocalcium phosphate monohydrate (MCPM) on polymerization kinetics and volumetric stability, apatite precipitation, strontium release and fatigue of novel dual-paste composites for vertebroplasty.

MATERIALS AND METHODS

Polypropylene (PPGDMA) or triethylene (TEGDMA) glycol dimethacrylates (25 wt%) diluents were combined with urethane dimethacrylate (70 wt%) and hydroxyethyl methacrylate (5 wt%). 70 wt% filler containing glass particles, glass fibers (20 wt%) and polylysine (5 wt%) was added. Benzoyl peroxide and MCPM (10 or 20 wt%) or N-tolyglycine glycidyl methacrylate and tristrontium phosphate (15 wt%) were included to give initiator or activator pastes. Commercial PMMA (Simplex) and bone composite (Cortoss) were used for comparison. ATR-FTIR was used to determine thermal activated polymerization kinetics of initiator pastes at 50-80°C. Paste stability, following storage at 4-37°C, was assessed visually or through mixed paste polymerization kinetics at 25°C. Polymerization shrinkage and heat generation were calculated from final monomer conversions. Subsequent expansion and surface apatite precipitation in simulated body fluid (SBF) were assessed gravimetrically and via SEM. Strontium release into water was assessed using ICP-MS. Biaxial flexural strength (BFS) and fatigue properties were determined at 37°C after 4 weeks in SBF.

RESULTS

Polymerization profiles all exhibited an inhibition time before polymerization as predicted by free radical polymerization mechanisms. Initiator paste inhibition times and maximum reaction rates were described well by Arrhenius plots. Plot extrapolation, however, underestimated lower temperature paste stability. Replacement of TEGDMA by PPGDMA, enhanced paste stability, final monomer conversion, water-sorption induced expansion and strontium release but reduced polymerization shrinkage and heat generation. Increasing MCPM level enhanced volume expansion, surface apatite precipitation and strontium release. Although the experimental composite flexural strengths were lower compared to those of commercially available Simplex, the extrapolated low load fatigue lives of all materials were comparable.

CONCLUSIONS

Increased inhibition times at high temperature give longer predicted shelf-life whilst stability of mixed paste inhibition times is important for consistent clinical application. Increased volumetric stability, strontium release and apatite formation should encourage bone integration. Replacing TEGDMA by PPGDMA and increasing MCPM could therefore increase suitability of the above novel bone composites for vertebroplasty. Long fatigue lives of the composites may also ensure long-term durability of the materials.

Analysis of the Causes on Poor Clinical Efficacy of Kyphoplasty Performed in Unilateral Transpedicular Puncture for the Treatment of Senile Osteoporotic Vertebral Compression Fractures

This study intends to analyze the causes on poor clinical efficacy of kyphoplasty performed in unilateral transpedicular puncture for the treatment of senile osteoporotic vertebral compression fractures. A retrospective study was conducted on a consecutive series of 70 patients who had underwent kyphoplasty performed in unilateral transpedicular puncture for the treatment of senile osteoporotic vertebral compression fractures between March 2016 to March 2017. These patients were compared for clinical data to investigate the causes on poor clinical efficacy of kyphoplasty performed in unilateral transpedicular puncture for the treatment of senile osteoporotic vertebral compression fractures. Comparison result of the indices between these patients showed that the differences in body weight, fracture type and bone cement dispersion were statistically significant. Logistic multivariate regression analysis showed body weight (OR = 0.892, p = 0.042), fracture type 2 (OR = 0.089, p = 0.020) and bone cement dispersion (OR = 4.773, p = 0.025) are risk factors for poor clinical efficacy. The results of corresponding analysis on VAS (Visual Analogue Scale), vertebral height and Cobb angle in patients with poor clinical efficacy showed that there is a correlation between them. We believe that patients' weight, dispersion degree of bone cement and fracture type of injured vertebra are the risk factors of kyphoplasty with poor clinical efficacy.

Clinical, Radiographic, and Morphometric Risk Factors for Adjacent and Remote Vertebral Compression Fractures Over a Minimum Follow-up of 4 Years After Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures: Novel Three-dimensional Voxel-Based Morphometric Analysis

OBJECTIVE

This study aimed to analyze the risk factors for secondary new vertebral compression fractures (SNVCFs) after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures.

METHODS

We evaluated the association of SNVCFs (adjacent vertebral compression fractures [AVCFs] and remote vertebral compression fractures) with clinical, radiographic, and PVP procedure-related morphologic parameters based on the data collected from 402 patients over a minimum follow-up of 4 years after PVP. Procedure-related morphologic parameters were assessed using a three-dimensional voxel-based analysis. Univariate and multivariate regression analyses were conducted.

RESULTS

On univariate analysis, bone mineral density (BMD), preoperative compression ratio, preoperative sagittal index (SI), and intradiscal bone cement leakage were significantly associated with SNVCF and AVCF (P < 0.05), whereas only BMD and preoperative SI were significantly associated with remote vertebral compression fracture (P < 0.05). A large ratio of bone cement volume to vertebral body volume and skewed bone cement distribution along the inferior-to-superior axis were especially significant risk factors for AVCF (P = 0.027 and P = 0.029, respectively). On multivariate analysis, BMD was significantly associated with SNVCF (P = 0.041), whereas upper adjacent intradiscal bone cement leakage was significantly associated with AVCF (P = 0.003).

CONCLUSIONS

Low BMD, high preoperative compression ratio, and high preoperative SI may be predictive factors for SNVCFs. In particular, to prevent AVCF, the injected bone cement should be distributed both evenly and symmetrically along the inferior-to-superior axis and the relative bone cement volume should not be excessive. Bone cement should be injected carefully to avoid upper adjacent intradiscal leakage. Prompt BMD correction is important to prevent SNVCF.

Clinical application of the pedicle in vitro restorer in percutaneous kyphoplasty

Background

Percutaneous kyphoplasty (PKP) is widely applied for the treatment of osteoporotic vertebral compression fractures (OVCFs) and has achieved satisfactory clinical results. With the accumulation of clinical cases and prolonged follow-up times, the inability to reconstruct vertebral height defects has attracted more and more attention. A comparison of clinical effects was retrospectively reviewed in 72 patients who underwent simple PKP or pedicle in vitro restorer (PIVR) combined with PKP to discuss the clinical application of self-developed PIVR used in PKP.

Methods

From August 2013 to August 2016, 72 patients with OVCFs were treated surgically, with 30 patients undergoing PKP (group A) and 42 undergoing PIVR combined with PKP (group B). Operation-related situations, radiological data, and related scores were compared between the two groups by corresponding statistical methods.

Results

Bone cement was successfully injected into 72 vertebral bodies. Sixty-three cases were followed up for an average of 14 months. There were significant differences between the two groups in the improvement of the height of the vertebral body, sagittal Cobb angle, and visual analogue scale (VAS) 1 week after the operation (P < 0.05), and the improvements of group B were better than those in group A. The cement leakage ratio was significantly different between the two groups (P < 0.05). The Oswestry Disability Index (ODI) at last follow-up was significantly different between the two groups (P < 0.05). There was no significant difference in the incidence of recurrent vertebral fractures between the two groups at the last follow-up (P > 0.05).

Conclusion

PIVR combined with PKP can overcome the limitations of PKP alone, that is, hardly restoring vertebral height and height being easily lost again with balloon removal. The combined method can also restore the vertebral fractures to a satisfactory height and effectively maintain the stability of the spine, which improves the long-term quality of life of patients. Thus, PIVR combined with PKP is a better choice for patients with OVCFs.

Clinical outcome comparison of polymethylmethacrylate bone cement with and without mineralized collagen modification for osteoporotic vertebral compression fractures

A retrospective study of consecutive patients.The purpose of this study was to compare the clinical effect of biomimetic mineralized collagen (MC) modified polymethylmethacrylate (PMMA) bone cement and traditional PMMA bone cement for the treatment of osteoporotic vertebral compression fractures (OVCF).New fracture on adjacent level is the major postoperative complication of percutaneous vertebroplasty (PVP). The clinical incidence was 12.4% to 27.7%. The increased stiffness of the treated vertebral body caused by filling bone cement is considered as one of the main reasons.A total of 30 patients treated with traditional PMMA bone cement from June 2013 to March 2016 were selected as the traditional group, while 50 patients treated with MC modified PMMA bone cement from July 2014 to March 2016 were selected as the modified group. The 2 groups were compared by injection time of the bone cements, postoperative pain relief effects, vertebral height restoration, CT value changes of the treated vertebral bodies, and postoperative complications in the clinical observations.The surgeries were successfully completed in both groups. In the treatment of OVCF, the MC modified bone cement was able to achieve the same pain relief and vertebral height restoration effects compared to traditional bone cement during the follow-ups, although the injection time of the cement was prolonged in the operation. MC modified bone cement significantly reduced the incidence of postoperative adjacent vertebral fracture from 13.3% to 2%, and significantly increased bone density of the treated vertebral bodies.The MC modified PMMA bone cement showed good clinical outcomes and better mechanical properties than the traditional bone cements.

Cement Distribution Patterns Are Associated with Recompression in Cemented Vertebrae After Percutaneous Vertebroplasty: A Retrospective Study

OBJECTIVE

To reevaluate the cement distribution patterns and further investigate associations between cement distribution patterns and the occurrence rates of recompression in cemented vertebrae after percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures.

METHODS

Two hundred twenty-four patients with a mean age of 71.9 years were enrolled and treated with single-level PVP between June 2012 and July 2015. The mean follow-up time was 16.5 months. Data from medical records and radiographs were collected and analyzed. Cement distribution patterns were divided into 4 cement distribution patterns extending from the traditional 2 patterns: interlocked solid pattern (LS) and uninterlocked solid pattern (ULS); contiguous trabecular pattern (CT) and discontiguous trabecular pattern (DCT). Differences in treatment efficacy and the occurrence rates of recompression in cemented vertebrae were compared for both groups using the Wilcoxon rank sum test and chi-squared test.

RESULTS

Thirty-seven patients who underwent PVP developed recompression in cemented vertebrae. Recompression in cemented vertebrae was significantly more frequent in the ULS and DCT groups than in the LS and CT groups (P < 0.05 or 0.001), with the Visual Analogue Scale score at the time of final follow-up was also significantly higher in the ULS and DCT groups (P < 0.001).

CONCLUSIONS

Significant associations were found between cement distribution patterns and recompression in cemented vertebrae, which affected the clinical outcome in patients after PVP. A higher incidence of recompression in cemented vertebrae was seen in patients with treated vertebrae exhibiting ULS pattern or DCT pattern.

Multiple vertebral fractures associated with glucocorticoid-induced osteoporosis treated with teriparatide followed by kyphosis correction fusion: a case report

Surgical treatment of multiple vertebral fractures in patients with glucocorticoid-induced osteoporosis is difficult because of a high rate of secondary fracture postoperatively. A case is described in which initial treatment with teriparatide to improve osteoporosis followed by treatment of kyphosis with correction fusion achieved a favorable outcome.

INTRODUCTION

Secondary fracture frequently occurs after treatment of vertebral fracture with vertebroplasty and balloon kyphoplasty in patients with glucocorticoid-induced osteoporosis, but effective treatment of multiple vertebral fractures has rarely been reported. Thus, a treatment of kyphosis following multiple vertebral fractures associated with glucocorticoid-induced osteoporosis is required.

METHODS

The patient was a 24-year-old woman diagnosed with glucocorticoid-induced osteoporosis who was under treatment with oral alendronate, vitamin D, and elcatonin injection. Secondary multiple vertebral fractures occurred despite these treatments and low back pain gradually aggravated.

RESULTS

Vertebroplasty or balloon kyphoplasty was not performed in the early phase. Instead, treatment with teriparatide was used for initial improvement of osteoporosis. Kyphosis in the center of the residual thoracolumbar junction was then treated with posterior correction fusion. At 2 years after surgery, the corrected position has been maintained and no new fracture has occurred.

CONCLUSION

There is no established method for treatment of multiple vertebral fractures caused by glucocorticoid-induced osteoporosis. Initial treatment with teriparatide to improve osteoporosis followed by treatment of kyphosis with correction fusion may result in a more favorable outcome.

Analysis of risk factors causing short-term cement leakages and long-term complications after percutaneous kyphoplasty for osteoporotic vertebral compression fractures

Background Percutaneous kyphoplasty (PKP) is a common treatment modality for painful osteoporotic vertebral compression fractures (OVCFs). Pre- and postoperative identification of risk factors for cement leakage and follow-up complications would therefore be helpful but has not been systematically investigated. Purpose To evaluate pre- and postoperative risk factors for the occurrence of short-term cement leakages and long-term complications after PKP for OVCFs. Material and Methods A total of 283 vertebrae with PKP in 239 patients were investigated. Possible risk factors causing cement leakage and complications during follow-up periods were retrospectively assessed using multivariate analysis. Cement leakage in general, three fundamental leakage types, and complications during follow-up period were directly identified through postoperative computed tomography (CT). Results Generally, the presence of cortical disruption ( P = 0.001), large volume of cement ( P = 0.012), and low bone mineral density (BMD) ( P = 0.002) were three strong predictors for cement leakage. While the presence of intravertebral cleft and Schmorl nodes ( P = 0.045 and 0.025, respectively) were respectively identified as additional risk factors for paravertebral and intradiscal subtype of cortical (C-type) leakages. In terms of follow-up complications, occurrence of cortical leakage was a strong risk factor both for new VCFs ( P = 0.043) and for recompression ( P = 0.004). Conclusion The presence of cortical disruption, large volume of cement, and low BMD of treated level are general but strong predictors for cement leakage. The presence of intravertebral cleft and Schmorl nodes are additional risk factors for cortical leakage. During follow-up, the occurrence of C-type leakage is a strong risk factor, for both new VCFs and recompression.

Compressive fatigue properties of commercially available standard and low-modulus acrylic bone cements intended for vertebroplasty

Vertebroplasty (VP) is a minimally invasive surgical procedure commonly used to relieve severe back pain associated with vertebral compression fractures. The poly(methyl methacrylate) bone cement used during this procedure is however presumed to facilitate the occurrence of additional fractures next to the treated vertebrae. A reason for this is believed to be the difference in stiffness between the bone cement and the surrounding trabecular bone. The use of bone cements with lower mechanical properties could therefore reduce the risk of complications post-surgery. While intensive research has been performed on the quasi-static mechanical properties of these cements, there is no data on their long-term mechanical properties. In the present study, the in vitro compressive fatigue performance as well as quasi-static mechanical properties of two commercially available acrylic bone cements - a low-modulus cement (Resilience^®) and a standard cement (F20) from the same manufacturer - were determined. The quasi-static mechanical properties of the low-modulus and standard cements after 24 h of setting were in the range of other vertebroplastic cements (σ = 70-75 MPa; E= 1600-1900 MPa). F20 displayed similar mechanical properties over time in 37 °C phosphate buffered saline solution, while the mechanical properties of the Resilience^® cement decreased gradually due to an increased porosity in the polymeric matrix. The standard cement exhibited a fatigue limit of approx. 47 MPa, whereas the low-modulus cement showed a fatigue limit of approx. 31 MPa. In summary, the low-modulus bone cement had a lower fatigue limit than the standard cement, as expected. However, this fatigue limit is still substantially higher than the stresses experienced by vertebral trabecular bone.

Risk factor analysis for re-collapse of cemented vertebrae after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP)

PURPOSE

Re-collapse of cemented vertebrae occasionally occurs after percutaneous augmentation. However, the potential risks still remain unclear. Several articles have reported some possible risk factors which were not consistent or comprehensive. This study aimed to make a retrospective review on patients with osteoporotic vertebral compression fracture (OVCF) after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) and to further analyse the risk factors for treated vertebral refracture.

METHODS

All patients receiving the PKP/PVP with bilateral approach were retrospectively reviewed from January 2014 to January 2016, among whom 230 patients with single level augmentation (30 in refracture group and 200 in the non-refracture group) were enrolled according to inclusion criteria. The following covariates were reviewed: gender, age, height, weight, body mass index (BMI), bone mineral density (BMD), serum bone turnover markers, surgical parameters including approach, cement volume, anterior height, and Cobb angle restoration. Binary logistic regression analysis was used to determine the relative risk of re-collapse of cemented vertebrae.

RESULTS

Regarding the patient data, weight, BMI, and BMD were of statistical significance in refracture group (P < 0.01), among which only low BMD was a risk factor to cemented vertebral re-collapse (P = 0.022, OR = 4.197). In respect of surgical variables, the better restoration of anterior height and Cobb angle was found in refracture group (P < 0.05), both of which might increase the refracture risk but not be risk factors (P = 0.065, OR = 0.891, and P = 0.937, OR = 0.996, respectively). Besides, less injected cement (3.30 ± 0.84 ml vs 4.46 ± 1.10 ml, P = 0.000, OR = 19.433) and PKP (P = 0.007, OR = 13.332) significantly boosted the potential risk of refracture (P < 0.001).

CONCLUSION

Patients with low BMD, or undergoing PKP, or receiving a low volume of injected cement might have a high risk of re-collapse in surgical vertebrae.

Elastoplasty as a promising novel technique: Vertebral augmentation with an elastic silicone-based polymer

OBJECTIVE

Percutaneous vertebroplasty with polymethylmethacrylate (PMMA) restores the stiffness and the strength of fractured vertebral bodies, but changes the pattern of the stress transfer. This effect may cause a secondary fracture of the adjacent vertebrae. Elastoplasty has emerged as a new technique to overcome this complication. The aim of this study is to retrospectively evaluate the clinical results of the elastoplasty procedure.

MATERIALS AND METHODS

Thirthy nine patients (9 males, 30 females, 87 spinal levels) were clinically evaluated pre and postoperatively in terms of pain relief, leakage and silicone embolism. The mean age was 67 (range 38-84) years. The mean follow up period was 12,5 months. The patients were evaluated radiologically for the presence of adjacent level fractures postoperatively. Complications were recorded.

RESULTS

The mean VAS score decreased from 7,5 to 3,5 during the last follow-up. Symptomatic silicone pulmonary embolism was not encountered in any patients. Leakage was observed in 5 (13%) cases. There was an adjacent level fracture in 1 case and another fracture which was not at the adjacent level in another one. A hematoma occurred in the needle entry site in a patient with trombocytopenia (<70,000).

CONCLUSIONS

Elastoplasty is a safe, promising technique in the treatment of vertebral compression fractures (VCFs). Symptomatic silicone pulmonary embolism is not observed. The material's stiffness is close to intact vertebrae. Therefore, elastoplasty may be a good viable option in the treatment of VCFs as it cause less complications and can prevent adjacent level fractures.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Analysis of Risk Factors for Secondary New Vertebral Compression Fracture Following Percutaneous Vertebroplasty in Patients with Osteoporosis

OBJECTIVE

The aim of this article was to analyze risk factors for secondary new vertebral compression fractures (SNVCFs) after percutaneous vertebroplasty in patients with osteoporosis.

METHODS

We investigated medical records and radiologic images of patients undergoing percutaneous vertebroplasty for osteoporotic vertebral compression fracture between October 2009 and September 2014. We assessed patients' age, past medical history, and bone mineral content using computed tomography. Procedure-specific outcomes were assessed, including ratio of injected bone cement to vertebral body volume, bone cement distribution in the vertebral body (to identify degree of consistency in bone cement injection), presence of bone cement leakage into adjacent disc space, segmental kyphosis, and time interval between first and second fracture events.

RESULTS

Percutaneous vertebroplasty was performed in 293 patients (60 men and 233 women) with 336 affected levels. Of this cohort, 34 (14.6%) patients sustained SNVCFs. We compared patients in 2 groups: patients who experienced SNVCFs, and patients who did not experience fractures. Significant differences were identified in bone mineral content (P = 0.000) and bone cement distribution (P = 0.000). Patients exhibiting bone cement leakage into disc space revealed a higher incidence of SNVCF than patients without leakage (P = 0.039).

CONCLUSIONS

Poor bone mineral content can be a predictive factor of SNVCFs. To prevent SNVCFs, bone cement should be injected as evenly as possible into the vertebral body. Bone cement leakage into the disc space should be avoided.

Does vertebral augmentation lead to an increasing incidence of adjacent vertebral failure? A systematic review and meta-analysis

BACKGROUND

The aim of the present study was to evaluate whether vertebral augmentation technology increases the occurrence of adjacent vertebral fractures in patients with osteoporotic vertebral compression fractures (OVCFs).

MATERIALS AND METHODS

Databases, including MEDLINE, EMBASE and Cochrane library, were retrieved via PRISMA covering 1987 to 2015. The number of patients who suffered from adjacent secondary vertebral fractures was calculated. A meta-analysis, using indexes of odds ratios (OR) and 95% confidence intervals (95% CI), was conducted with STATA software. Subgroup investigations were conducted according to the operation methods and the duration of observation. Sensitivity analysis and publication bias were also evaluated.

RESULTS

Ten randomized controlled trials (RCTs) met our inclusion criteria. Our results indicated there was no statistically significant difference in the occurrence rate of adjacent vertebral fractures between manipulation of vertebral augmentation and non-surgical treatment (OR = 0.89, 95% CI = 0.58-1.37). Neither subgroup investigations based on selection of operation nor duration of follow-up time showed marked differences. A sensitivity analysis did not identify specific trails seriously deflected. No obvious publication bias was identified.

CONCLUSION

Despite various limitations in the present study, our data demonstrated that using vertebral augmentation was not related to increasing incidence of subsequent adjacent vertebral fractures.

In silico investigation of vertebroplasty as a stand-alone treatment for vertebral burst fractures

BACKGROUND

The use of percutaneous vertebroplasty as a stand-alone treatment for stable vertebral burst fractures has been investigated in vitro and in clinical studies. These studies present inconsistent results on the mechanical response of vertebroplasty-treated burst fractures. In addition, observations of the loss of sagittal alignment after vertebroplasty raise questions on the applicability of vertebroplasty for burst fractures. Therefore, the aim of this study was to investigate the mechanical stability of burst fractures after stand-alone treatment by vertebroplasty.

METHODS

Finite element simulations were performed with models generated from two laboratory-induced burst fractures in human thoracolumbar specimens. The burst fracture models were virtually injected with various cement volumes using a unipedicular or bipedicular approach. The models were subjected to four individual loads (compression, lateral bending, extension and torsion) and a multi-axial load case in the physiological range.

FINDINGS

All treated burst fractures showed improvements in stiffness and a reduction in inter-fragmentary displacements, thus potentially providing a suitable mechanical environment for fracture healing. However, large volumes of the trabecular bone (<43%), cement (<53%) and bone-cement composite (<58%) were predicted to experience strain levels exceeding the yield point. While damage was not specifically modeled, this implies a potential collapse of the treated vertebra due to local failure.

INTERPRETATION

To improve the primary stability and to prevent the collapse of treated burst fractures, the use of posterior instrumentation is suggested as an adjunct to vertebroplasty.

Gradual Height Decrease of Augmented Vertebrae after Vertebroplasty at the Thoracolumbar Junction

OBJECTIVE

Vertebroplasty is an effective treatment for vertebral compression fracture, but may progress gradual vertebral height decrease in spite of vertebroplasty. Gradual vertebral height decrease also may induce aggravation of kyphotic change without severe pain. The purpose of this study was to evaluate risk factors for gradual vertebral height decrease in the absence of recurrent severe back pain.

METHODS

A retrospective analysis was performed on 44 patients who were diagnosed with a first osteoporotic compression fracture at a single level at the thoracolumbar junction. All patients were taken vertebroplasty. Possible risk factors for gradual vertebral height decrease, such as sex, age, bone mineral density, body mass index, level of compression fracture, volume of injected cement, cement leakage into disc space, and air clefts within fractured vertebrae, were analyzed.

RESULTS

Gradual vertebral height decrease of augmented vertebrae occurred commonly when more than 4 cc of injected cement was used, and when air clefts within fractured vertebrae were seen on admission. In addition, the sagittal Cobb angle more commonly increased during the follow-up period in such cases.

CONCLUSION

Injection of more than 4 cc of cement during vertebroplasty and air cleft within fractured vertebrae on admission induced gradual vertebral height decrease in augmented vertebrae. Thus, longer follow-up will be needed in such cases, even when patients do not complain of recurrent severe back pain.

Risk factors for new vertebral compression fractures after vertebroplasty: a meta-analysis

BACKGROUND

The risk factors for new vertebral compression fractures (VCFs) after vertebroplasty are unclear. The aim of this meta-analysis was to identify potential risk factors.

METHODS

A systematic electronic literature search was performed using the following databases: PubMed, Embase and Cochrane Library; the databases were searched from the earliest available records in 1966 to May 2015. Pooled odds ratios (ORs) or standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using random- or fixed-effects models. The Newcastle-Ottawa scale was used to evaluate the methodological quality of the studies, and Stata 11.0 was used to analyse the data.

RESULTS

The primary factors that were associated with new fractures after vertebroplasty were low bone mineral density (SMD -0.375; 95% CI -0.579 to -0.171), steroid usage (OR 2.632; 95% CI 1.399 to 4.950) and the presence of multiple treated vertebrae (OR 2.027; 95% CI 1.442 to 2.851). The data did not support that age, sex, body mass index, non-steroidal anti-inflammatory drug usage, vacuum cleft, thoracolumbar junction, cement volume, kyphosis correction, or intradiscal cement leakage could lead to infection after vertebroplasty.

CONCLUSIONS

The present analysis demonstrated that low bone mineral density, the presence of multiple treated vertebrae and a history of steroid usage were associated with the new VCFs after vertebroplasty. Patients with these factors should be informed of the potential increased risk.