Risk factors for new vertebral fractures after percutaneous vertebroplasty in patients with osteoporosis: a prospective study

Appropriate Use Criteria for Osteoporotic Compression Fractures

BACKGROUND CONTEXT

There is a lack of consensus regarding optimal indications for treatment of patients with osteoporotic vertebral fractures. An opportunity exists to improve outcomes if these indications can be clarified.

PURPOSE

The purpose of the North American Spine Society (NASS) Appropriate Use Criteria (AUC) was to determine the appropriate (i.e. reasonable) multidisciplinary treatment recommendations for patients with osteoporotic vertebral fractures across a spectrum of more common clinical scenarios.

STUDY DESIGN

A Modified Delphi process.

PATIENT SAMPLE

Modified consensus based guideline OUTCOME MEASURES: Final rating for treatment recommendations as either "Appropriate", "Uncertain", or "Rarely Appropriate" based on the median final rating among the raters.

METHODS

The methodology was based on the AUC development process established by the Research AND Development (RAND) Corporation. The topic of osteoporotic vertebral compression fracture was selected by NASS for its Clinical Practice Guideline development (CPG). In conjunction, the AUC committee determined key modifiers and adapted the standard definitions developed by the CPG with minimal modifications. A literature search and evidence analysis performed by the CPG were reviewed by the AUC work group. A separate multidisciplinary rating group was assembled. Clinical scenarios were generated based on a matrix of the modifiers, to rate the appropriateness of medical management, cement augmentation, or surgery. Based on the literature, provider experience, and group discussion, each scenario was scored on a nine-point scale on two separate occasions: once without discussion and again following discussion of the initial responses. The median rating for each scenario and level of agreement was then used to determine final indications as rarely appropriate with agreement (1 - 3), uncertain or disagreement (4-6), or appropriate with agreement (7-9). Consensus was not mandatory.

RESULTS

Medical management was appropriate across all scenarios. Cement augmentation was rarely appropriate in 60% of scenarios and uncertain or disagreement in 35% of scenarios. In the 5% of scenarios rated as appropriate with agreement for cement augmentation, high pain scores, acute duration, and simple fracture pattern were always present. Surgery was appropriate in 35% of scenarios and strongly influenced by instability and stenosis with neurological findings. Surgery was rarely appropriate in 18%, and uncertain or disagreement in 47% of scenarios.

CONCLUSIONS

Multidisciplinary appropriate treatment criteria for osteoporotic vertebral fractures were generated based on the RAND methodology. This document provides comprehensive evidence-based recommendations for evaluation and treatment of osteoporotic vertebral fractures. The document in its entirety will be found on the NASS website (https://www.spine.org/Research-Clinical-Care/Quality-Improvement/Appropriate-Use-Criteria).

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of adults with osteoporotic vertebral compression fractures

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Adults with Osteoporotic Vertebral Compression Fractures features evidence-based recommendations for diagnosing and treating adult patients with osteoporotic vertebral compression fractures. The guideline is intended to reflect contemporary treatment concepts for osteoporotic vertebral compression fractures as reflected in the highest quality clinical literature available on this subject as of September 2020.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with osteoporotic vertebral compression fractures. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of NASS' Clinical Practice Guidelines Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with a medical librarian. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors.

RESULTS

Twenty-nine clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with osteoporotic vertebral compression fractures. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at http://www.spine.org/guidelines.

Prediction of subsequent vertebral fracture after percutaneous vertebral augmentation using MRI-based vertebral bone quality and CT-based Hounsfield units: a retrospective cross-sectional study

Subsequent vertebral fracture (SVF) is a common and refractory complication after percutaneous vertebral augmentation (PVA) for osteoporotic vertebral compression fracture (OVCF). Computed tomography (CT)-based Hounsfeld units (HU) and magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score can evaluate osteoporosis quantitatively, hyperlipidemia(HLP) might affect measurement result of VBQ score. The primary objective of this study is to compare the predictive capabilities of HU and VBQ for SVF, and to clarify the impact of hyperlipidemia on the predictive abilities. This study included consecutive 341 patients with OVCF who were treated with PVA from March 1, 2020, to December 31, 2022. A multivariate logistic regression analysis was used to determine the relationship between HU and VBQ and SVF. ROC curves were plotted to calculate area under curve (AUC), and hoc analysis and Youden index was used to determine cut-off values of HU and VBQ. Compared with the non-SVF group, VBQ (4.69 ± 0.35 vs. 4.14 ± 0.41, P < 0.001) was higher and HU (58.2 ± 13.81 vs. 81.2 ± 16.68, P < 0.001) was lower in the SVF group. On multivariate logistic regression analysis, higher VBQ (odds ratio (OR) = 23.47,P < 0.001) and lower HU (OR = 0.93,P < 0.001) are independent predictors for SVF. The AUC using VBQ for predicting SVF was 0.84, the cut-off was 4.28. The AUC using HU for predicting SVF was 0.85, the cut-off was 64.40. In the HLP group, the AUC of VBQ was comparable with that of HU for SVF prediction, however, the sensitivity was lower in the HLP group (0.50 vs. 0.83). Furthermore, the AUC value of VBQ with HLP was lower than that of VBQ without HLP (0.78 vs. 0.90, P = 0.017). These findings demonstrated that both VBQ and HU can accurately predict the occurrence of SVF after PVA. HLP might cause a false increase of VBQ value, using HU could better assess bone quality and predict SVF occurrence when HLP is present.

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.

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.

Association Between Bone Cement Augmentation and New Vertebral Fractures in Patients with Osteoporotic Vertebral Compression Fractures: A Systematic Review and Meta-Analysis

PURPOSE

To investigate the association between bone cement augmentation and new vertebral fractures (VF) in patients with osteoporotic vertebral compression fractures (OVCFs).

METHODS

A literature search of PubMed, EMBASE, and the Cochrane Library was conducted from 1987 to December 31, 2020, to identify randomized controlled trials that compared bone cement augmentation with non-bone cement treatments in patients with OVCFs. The clinical incidence of new VF and the risk of new adjacent vertebral fractures (AVF) after treatment were calculated. The indexes of the risk ratio or odds ratio, and 95% confidence intervals were determined with RevMan 5.2 software.

RESULTS

A total of 13 randomized controlled trials involving 1949 participants were included in the final quantitative analysis. There was no significant association between bone cement augmentation and the clinical incidence of new VF during the 6-month and 12-month follow-ups or the whole follow-up period. However, there was a significantly lower clinical incidence of new VF in patients who received bone cement augmentation compared with non-bone cement treatments during 24 months or more of follow-up. Pooled data from the relevant trials demonstrated that the risk of new AVF in bone cement augmentation was significantly higher than that in non-bone cement treatments.

CONCLUSIONS

Although the use of bone cement augmentation in OVCFs significantly increased the risk of new AVF compared with non-bone cement treatments, it was not significantly associated with a higher clinical incidence of new VF.

Risk of New Fractures in Vertebroplasty for Multiple Myeloma. A Retrospective Study

OBJECTIVE

Vertebroplasty is a percutaneous minimally invasive procedure indicated for vertebral collapse pain treatment. Among the known complications of the procedure is the augmented risk of new vertebral fractures. There are no specific studies in this patient population describing the risk of new vertebral fractures after vertebroplasty. This study analyzed risk factors associated with new vertebral fractures after vertebroplasty in patients with multiple myeloma.

METHODS

Observational retrospective study in patients with multiple myeloma. The data collection took place from January 1, 2010, to December 30, 2017, at the National Cancer Institute. Clinical data and procedural variables such as cement volume, cement leaks, fracture level, number of treated vertebrae, pedicular disease, and cement distribution pattern, with two years follow-up, were analyzed with the Wilcoxon test, and a logistic regression model was used to identify risk factors related to new vertebral fractures. A confidence interval of 95% was used for analysis.

RESULTS

At one-year follow-up, 30% of fractures were reported after vertebroplasty, most of them at low thoracic and lumbar level (50% adjacent level). Vertebroplasty was most commonly performed at the thoracolumbar and lumbar area. We demonstrated a 70.7% median numerical rating scale reduction at one-year follow-up; a significant decrease in opioid consumption occurred only during the first month.

CONCLUSIONS

Pedicle involvement, disc leakage, cement volume, thoracolumbar and lumbar level, and number of treated vertebrae by intervention are important risk factors when performing vertebroplasty. Prospective randomized studies are needed to evaluate these factors in this specific population.

Influence of the distribution of bone cement along the fracture line on the curative effect of vertebral augmentation

Objective

The present study was performed to evaluate the effect of different bone cement distributions along the fracture line on clinical and imaging outcomes of vertebral augmentation.

Methods

In total, 84 patients who underwent vertebral augmentation for a single osteoporotic vertebral compression fracture from January 2016 to August 2018 were retrospectively reviewed. These patients were divided into two groups according to the relationship between the bone cement distribution and the fracture line: the unilateral group (n = 23) and the bilateral group (n = 61). Postoperative clinical and imaging parameters were compared between the two groups.

Results

Statistical analyses showed no significant difference in postoperative pain relief, bone cement leakage, nerve injury, or new vertebral fracture between the two groups. Significant recovery from vertebral compression was observed in the bilateral group after surgery, but there was no significant difference in vertebral compression after surgery in the unilateral group.

Conclusions

Pain relief was similar for different types of cement distributions along the fracture line, but a bilateral cement distribution exhibited better recovery from vertebral compression and did not increase bone cement leakage in the vertebral augmentation procedure.

Cement injection and postoperative vertebral fractures during vertebroplasty

Objective

Vertebroplasty is the most widely used method for treating osteoporotic vertebral compression fractures (OVCF). During this procedure, bone cement is injected into the vertebral body. Fracture and additional fractures can occur adjacent to the treatment site. Thus, we studied factors causing such vertebral fractures after vertebroplasty and calculated the appropriate amount of bone cement to inject.

Methods

From September 2012 to March 2016, 187 patients with OVCF undergoing vertebroplasty were selected, and 112 patients with complete follow-up information were selected. Of these, 28 had adjacent vertebral fractures (refracture group) during the follow-up period, and 84 patients had no adjacent vertebral fractures (control group). Then, sex, age, body weight, bone mineral density (BMD), and bone cement injection (bone cement injection volume and bone fracture vertebral volume percent) were compared.

Results

All patients had significant pain relief within 24 h (preoperative and postoperative [24 h later] VAS scores were 7.4 ± 0.8 and 2.3 ± 0.5, respectively). The age and weight were not statistically significantly different (P > 0.05). BMD values were statistically significantly different between groups as was sex (P < 0.05).

Conclusions

Bone cement injection volume, BMD values, and sex were statistically significantly related to adjacent vertebral fractures after vertebroplasty, and cement injection volumes exceeding 40.5% caused adjacent vertebral fractures.

The outcomes of percutaneous kyphoplasty in treatment of the secondary osteoporotic vertebral compression factures: a case-control study

Background

To investigate the outcomes of using percutaneous kyphoplasty in the treatment of the secondary osteoporotic vertebral compression fractures.

Methods

Eighty-one patients had the secondary single segmental osteoporotic vertebral compression fractures after the initial fractures and treated by percutaneous kyphoplasty were reviewed, 74 of them had minimum 2 years follow-up were included in this study. The 74 patients with primary osteoporotic vertebral compression fractures treated by percutaneous kyphoplasty at the same time period were matched as control group in 1:1 ratio. Visual Analogue Scales (VAS) and Oswestry Disability Index (ODI) were used to assess the back pain and functional outcomes. The kyphotic angulation (KA) and compression ratio (CR) of the fractured vertebra was measured too.

Results

Both the secondary fracture group and control group had significantly relieved back pain, improved functional outcomes, corrected KA and restored CR after operation, but no difference was found between two groups.

Conclusions

Our findings suggest that percutaneous kyphoplasty is an effective and safe procedure for patients with secondary single segmental osteoporotic vertebral compression fractures; it can achieve similar clinical outcomes to the primary osteoporotic vertebral compression fractures.

Vertebral Body Compressive Strength Evaluated by Dual-Energy X-Ray Absorptiometry and Hounsfield Units In Vitro

Dual-energy X-ray absorptiometry (DXA) and Hounsfield unit (HU) are 2 technologies used in vivo to assess bone mineral density and to predict fracture risk. However, few in vitro studies focus on the difference between the 2 technologies in the ability to determine vertebral body compressive strength. Forty-two lumbar vertebrates were harvested from 7 mature goats. All the vertebrae were imaged using clinical computed tomography and assessed by DXA subsequently. The individual vertebral body was then mechanically tested to failure in compression, to determine ultimate load and stress. HU has a moderate correlation with DXA (r = 0.64). DXA has significant associations with ultimate load and stress (r = 0.59 and 0.69, respectively). Significant positive linear correlations were also found between HU and ultimate load (r = 0.65) and stress (r = 0.81). There was no significant difference between HU and DXA to predict the ultimate load (t = 0.56, p = 0.577) or the ultimate stress (t = 1.62, p = 0.112). HU has an equal predictive value as the DXA for whole vertebral body compressive strength. This work supports the application of the HU measurement using clinical computed tomography imaging technology to assess bone strength and fracture risk.

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.

Risk Prediction of New Adjacent Vertebral Fractures After PVP for Patients with Vertebral Compression Fractures: Development of a Prediction Model

PURPOSE

We aim to determine the predictors of new adjacent vertebral fractures (AVCFs) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs) and to construct a risk prediction score to estimate a 2-year new AVCF risk-by-risk factor condition.

MATERIALS AND METHODS

Patients with OVCFs who underwent their first PVP between December 2006 and December 2013 at Hospital A (training cohort) and Hospital B (validation cohort) were included in this study. In training cohort, we assessed the independent risk predictors and developed the probability of new adjacent OVCFs (PNAV) score system using the Cox proportional hazard regression analysis. The accuracy of this system was then validated in both training and validation cohorts by concordance (c) statistic.

RESULTS

421 patients (training cohort: n = 256; validation cohort: n = 165) were included in this study. In training cohort, new AVCFs after the first PVP treatment occurred in 33 (12.9%) patients. The independent risk factors were intradiscal cement leakage and preexisting old vertebral compression fracture(s). The estimated 2-year absolute risk of new AVCFs ranged from less than 4% in patients with neither independent risk factors to more than 45% in individuals with both factors.

CONCLUSIONS

The PNAV score is an objective and easy approach to predict the risk of new AVCFs.

A Classification System for the Spread of Polymethyl Methacrylate in Vertebral Bodies Treated with Vertebral Augmentation

In this study, we develop a classification system for describing polymethyl methacrylate (PMMA) spread in vertebral bodies after kyphoplasty or vertebroplasty for vertebral compression fractures (VCFs) and for assessing whether PMMA spread varies between operators, VCF etiology, or vertebral level. Intraoperative fluoroscopic images of 198 vertebral levels were reviewed in 137 patients (women, 84; men, 53; mean age, 75.8 ± 12.5; and those with a diagnosis of osteoporosis, 63%) treated with kyphoplasty between January 01, 2015 and May 31, 2015 at a single center to create a 5-class descriptive system. PMMA spread patterns in the same images were then classified by 2 board-certified radiologists, and a third board-certified radiologist resolved conflicts. A total of 2 primary PMMA spread patterns were identified, namely, acinar and globular, with subtypes of localized acinar, diffuse globular, and mixed, to describe an equal combination of patterns. Interrater reliability using the system was moderate (κ = 0.47). After resolving conflicts, the most common spread class was globular (n = 63), followed by mixed (n = 58), diffuse globular (n = 30), acinar (n = 27), and localized acinar (n = 20). The spread class after treatment by the 2 most frequent operators differed significantly (n₁ = 63, n₂ = 70; P < .0001). There was no difference in the spread class between VCF etiologies or vertebral levels. PMMA spread may, therefore, be a modifiable parameter that affects kyphoplasty and vertebroplasty efficacy and adverse events.

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.

Thoracic and lumbar vertebral bone mineral density changes in a natural occurring dog model of diffuse idiopathic skeletal hyperostosis

Ankylosing spinal disorders can be associated with alterations in vertebral bone mineral density (BMD). There is however controversy about vertebral BMD in patients wuse idiopathic skeletal hyperostosis (DISH). DISH in Boxer dogs has been considered a natural occurring disease model for DISH in people. The purpose of this study was to compare vertebral BMD between Boxers with and without DISH. Fifty-nine Boxers with (n=30) or without (n=29) DISH that underwent computed tomography were included. Vertebral BMD was calculated for each thoracic and lumbar vertebra by using an earlier reported and validated protocol. For each vertebral body, a region of interest was drawn on the axial computed tomographic images at three separate locations: immediately inferior to the superior end plate, in the middle of the vertebral body, and superior to the inferior end plate. Values from the three axial slices were averaged to give a mean Hounsfield Unit value for each vertebral body. Univariate statistical analysis was performed to identify factors to be included in a multivariate model. The multivariate model including all dogs demonstrated that vertebral DISH status (Coefficient 24.63; 95% CI 16.07 to 33.19; p <0.001), lumbar vertebrae (Coefficient -17.25; 95% CI -23.42 to -11.09; p < 0.01), and to a lesser extent higher age (Coefficient -0.56; 95% CI -1.07 to -0.05; p = 0.03) were significant predictors for vertebral BMD. When the multivariate model was repeated using only dogs with DISH, vertebral DISH status (Coefficient 20.67; 95% CI, 10.98 to 30.37; p < 0.001) and lumbar anatomical region (Coefficient -38.24; 95% CI, -47.75 to -28.73; p < 0.001) were again predictors for vertebral BMD but age was not. The results of this study indicate that DISH can be associated with decreased vertebral BMD. Further studies are necessary to evaluate the clinical importance and pathophysiology of this finding.

Use of computed tomography for assessing bone mineral density

Assessing local bone quality on CT scans with Hounsfield unit (HU) quantification is being used with increasing frequency. Correlations between HU and bone mineral density have been established, and normative data have been defined throughout the spine. Recent investigations have explored the utility of HU values in assessing fracture risk, implant stability, and spinal fusion success. The information provided by a simple HU measurement can alert the treating physician to decreased bone quality, which can be useful in both medically and surgically managing these patients.

Risks and benefits of percutaneous vertebroplasty or kyphoplasty in the management of osteoporotic vertebral fractures

Vertebral fracture (VF) is the most common osteoporotic fracture and is associated with high morbidity and mortality. Conservative treatment combining antalgic agents and rest is usually recommended for symptomatic VFs. The aim of this paper is to review the randomized controlled trials comparing the efficacy and safety of percutaneous vertebroplasty (VP) and percutaneous balloon kyphoplasty (KP) versus conservative treatment. VP and KP procedures are associated with an acceptable general safety. Although the case series investigating VP/KP have all shown an outstanding analgesic benefit, randomized controlled studies are rare and have yielded contradictory results. In several of these studies, a short-term analgesic benefit was observed, except in the prospective randomized sham-controlled studies. A long-term analgesic and functional benefit has rarely been noted. Several recent studies have shown that both VP and KP are associated with an increased risk of new VFs. These fractures are mostly VFs adjacent to the procedure, and they occur within a shorter time period than VFs in other locations. The main risk factors include the number of preexisting VFs, the number of VPs/KPs performed, age, decreased bone mineral density, and intradiscal cement leakage. It is therefore important to involve the patients to whom VP/KP is being proposed in the decision-making process. It is also essential to rapidly initiate a specific osteoporosis therapy when a VF occurs (ideally a bone anabolic treatment) so as to reduce the risk of fracture. Randomized controlled studies are necessary in order to better define the profile of patients who likely benefit the most from VP/KP.

Risk factors for the development of vertebral fractures after percutaneous vertebroplasty

We have recently observed an increased risk for vertebral fractures (VF) in a randomized controlled trial comparing the analgesic effect of vertebroplasty (VP) versus conservative treatment in symptomatic VF. The aim of the present study was to evaluate the risk factors related to the development of VF after VP in these patients. We evaluated risk factors including age, gender, bone mineral density, the number, type, and severity of vertebral deformities at baseline, the number of vertebral bodies treated, the presence and location of disk cement leakage, bone remodeling (determining bone turnover markers) and 25 hydroxyvitamin D [25(OH)D] levels at baseline in all patients. Twenty-nine radiologically new VF were observed in 17 of 57 patients undergoing VP, 72% adjacent to the VP. Patients developing VF after VP showed an increased prevalence of 25(OH)D deficiency (<20 ng/mL) and higher P1NP values. The principal factor related to the development of VF after VP in multivariate analysis was 25(OH)D levels < 20 ng/mL (RR, 15.47; 95% CI, 2.99-79.86, p < 0.0001), whereas age >80 years (RR, 3.20; 95% CI, 1.70-6.03, p = 0.0007) and glucocorticoid therapy (RR, 3.64; 95% CI, 1.61-8.26, p = 0.0055) constituted the principal factors in the overall study population. Increased risk of VF after VP was also associated with cement leakage into the inferior disk (RR, 6.14; 95% CI, 1.65-22.78, p = 0.044) and more than one vertebral body treated during VP (RR, 4.19; 95% CI, 1.03-34.3, p = 0.044). In conclusion, nearly 30% of patients with osteoporotic VF treated with VP had a new VF after the procedure. Age, especially >80 years, the presence of inferior disk cement leakage after the procedure, the number of cemented vertebrae, and low 25(OH)D serum levels were related to the development of new VF in these patients, with the latter indicating the need to correct vitamin D deficiency prior to performing VP.

Risk factors for new vertebral compression fractures after percutaneous vertebroplasty: qualitative evidence synthesized from a systematic review

STUDY DESIGN

Methodological systematic review.

OBJECTIVE

To identify the risk factors for new vertebral compression fractures (VCFs) in patients after percutaneous vertebroplasty (PVP) and to grade the evidence according to the quality of included studies.

SUMMARY OF BACKGROUND DATA

PVP is an effective procedure for the treatment of VCFs. A major concern after PVP in patients with osteoporosis is the occurrence of new VCFs in the untreated vertebrae. The risk factors for new VCFs after PVP reported thus far remain controversial. These risk factors have neither been well identified or summarized. This systematic review was performed to identify the risk factors for new VCFs after PVP.

METHODS

Noninterventional studies evaluating the risk factors for new VCFs of patients with osteoporosis after PVP were searched in MEDLINE, EMBASE, ScienceDirect, and OVID databases (all up to November 2012). Only observational studies with eligible data were included. Quality of included studies was assessed by a modified quality assessment tool, which was previously designed for observational study. The effects of studies were combined with the study quality score using a model of best-evidence synthesis.

RESULTS

Twenty-four observational studies involving 3789 patients were included. These articles were published between 2004 and 2012. According to the quality assessment criteria for included studies, 8 studies were deemed as high-quality studies, 6 as moderate-quality studies, and 10 as low-quality studies. There were strong evidences of 3 risk factors, including lower bone mineral density, lower body mass index, intradiscal cement leakage, and vertebral height restoration. We also identified 6 moderate-evidence factors including lower body mass index, number of pre-existing vertebral fractures, thoracolumbar junction in initial VCFs, cement distraction, older age, and number of treated vertebrae. Thirteen factors were classified into the limited-evidence risk factors.

CONCLUSION

Although there is no conclusive evidence for new VCFs of patients with osteoporosis after PVP procedure, these data provide evidence to guide the surgeon and develop optimal preventions for new VCFs after PVP. Special attention should be paid to the 3 strong-evidence risk factors. Further studies were still required to evaluate the effects of the earlier mentioned risk factors.

LEVEL OF EVIDENCE

2.