The analysis of patterns and risk factors of newly developed vertebral compression fractures after percutaneous vertebroplasty

Preoperative Prediction of New Vertebral Fractures after Vertebral Augmentation with a Radiomics Nomogram

The occurrence of new vertebral fractures (NVFs) after vertebral augmentation (VA) procedures is common in patients with osteoporotic vertebral compression fractures (OVCFs), leading to painful experiences and financial burdens. We aim to develop a radiomics nomogram for the preoperative prediction of NVFs after VA. Data from center 1 (training set: n = 153; internal validation set: n = 66) and center 2 (external validation set: n = 44) were retrospectively collected. Radiomics features were extracted from MRI images and radiomics scores (radscores) were constructed for each level-specific vertebra based on least absolute shrinkage and selection operator (LASSO). The radiomics nomogram, integrating radiomics signature with presence of intravertebral cleft and number of previous vertebral fractures, was developed by multivariable logistic regression analysis. The predictive performance of the vertebrae was level-specific based on radscores and was generally superior to clinical variables. RadscoreL2 had the optimal discrimination (AUC ≥ 0.751). The nomogram provided good predictive performance (AUC ≥ 0.834), favorable calibration, and large clinical net benefits in each set. It was used successfully to categorize patients into high- or low-risk subgroups. As a noninvasive preoperative prediction tool, the MRI-based radiomics nomogram holds great promise for individualized prediction of NVFs following VA.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Development and validation of a machine learning model to predict imminent new vertebral fractures after vertebral augmentation

BACKGROUND

Accurately predicting the occurrence of imminent new vertebral fractures (NVFs) in patients with osteoporotic vertebral compression fractures (OVCFs) undergoing vertebral augmentation (VA) is challenging with yet no effective approach. This study aim to examine a machine learning model based on radiomics signature and clinical factors in predicting imminent new vertebral fractures after vertebral augmentation.

METHODS

A total of 235 eligible patients with OVCFs who underwent VA procedures were recruited from two independent institutions and categorized into three groups, including training set (n = 138), internal validation set (n = 59), and external validation set (n = 38). In the training set, radiomics features were computationally retrieved from L1 or adjacent vertebral body (T12 or L2) on T1-w MRI images, and a radiomics signature was constructed using the least absolute shrinkage and selection operator algorithm (LASSO). Predictive radiomics signature and clinical factors were fitted into two final prediction models using the random survival forest (RSF) algorithm or COX proportional hazard (CPH) analysis. Independent internal and external validation sets were used to validate the prediction models.

RESULTS

The two prediction models were integrated with radiomics signature and intravertebral cleft (IVC). The RSF model with C-indices of 0.763, 0.773, and 0.731 and time-dependent AUC (2 years) of 0.855, 0.907, and 0.839 (p < 0.001 for all) was found to be better predictive than the CPH model in training, internal and external validation sets. The RSF model provided better calibration, larger net benefits (determined by decision curve analysis), and lower prediction error (time-dependent brier score of 0.156, 0.151, and 0.146, respectively) than the CPH model.

CONCLUSIONS

The integrated RSF model showed the potential to predict imminent NVFs following vertebral augmentation, which will aid in postoperative follow-up and treatment.

Prediction model of adjacent vertebral compression fractures after percutaneous kyphoplasty: a retrospective study

OBJECTIVES

The purpose of this study was to develop a prediction model to assess the risk of adjacent vertebral compression fractures (AVCFs) after percutaneous kyphoplasty (PKP) surgery.

DESIGN

A retrospective chart review.

SETTING AND PARTICIPANTS

Patients were collected from the Quzhou People's Hospital, from March 2017 to May 2019. Patients were included if they suffered from osteoporotic vertebral compression fractures (OVCFs), underwent PKP surgery and were followed up for 2 years.

INTERVENTIONS

None.

METHODS

This was a retrospective cohort study of all PKP surgery procedures of the thoracic, lumbar and thoracolumbar (TL) spine that have been performed for OVCF from 1 March 2017 up to 1 May 2019. The least absolute shrinkage and selection operator (LASSO) regression model was used to optimise feature selection for the AVCF risk model. Multivariable logistic regression analysis was applied to build a predicting model incorporating the feature selected in the LASSO regression model. The C-index, calibration plot and decision curve analysis were applied to assess this model.

RESULTS

Gender, age, the number of surgical vertebrae, cement volume, bone mineral density, diabetes, hypertension, bone cement leakage, duration of anti-osteoporosis treatment after surgery and TL junction were identified as predictors. The model displayed good discrimination with a C-index of 0.886 (95% CI 0.828-0.944) and good calibration. High C-index value of 0.833 could still be reached in the interval validation. Decision curve analysis showed that the AVCF nomogram was clinically useful when intervention was decided at the AVCF possibility threshold of 1%.

CONCLUSIONS

This study developed a clinical prediction model to identify the risk factors for AVCF after PKP surgery, and this tool is of great value in sharing surgical decision-making among patients consulted before surgery.

TRIAL REGISTRATION NUMBER

researchregistry7716.

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.

Risk factors for new vertebral compression fracture after kyphoplasty and efficacy of osteoporosis treatment: A STROBE-compliant retrospective study

Kyphoplasty (KP) has been widely used to treat vertebral compression fractures (VCFs). However, the issue of new VCFs after KP remains controversial. Identification of risk factors for new VCF after KP may help prevent their occurrence in patients. This study aimed to retrospectively determine the major risk factors for new VCF after KP, including those associated with osteoporosis drugs used after kyphoplasty. We reviewed 117 patients who underwent single-level KP. During the follow-up period of 1 year after KP, the demographic data of these patients were compared by dividing them into two groups: those with new fractures (n = 19) and those without new fractures (n = 98). We investigated the age, sex, fracture location, medical history, steroid use history, bone mineral density (BMD), type of osteoporosis treatment, period from fracture to KP, KP method (unilateral or bilateral), bone cement dose, intradiscal cement leakage, preoperative and postoperative compression ratio, kyphotic angle (KA), and lowest vertebral body height in the fractured vertebrae. Based on these data, the factors related to new VCFs after KP were investigated using univariate and multivariate logistic regression analyses. We also investigated whether there were differences in new VCFs according to the type of osteoporosis treatment. During the 1-year follow-up period after KP, the rate of new VCFs was 16.2%. Factors related to new VCFs were BMD, intradiscal cement leakage, KA recovery rate after 1 day, and baseline height in the univariate and multivariate logistic regression analyses. The group treated with zoledronate after KP tended to show a lower frequency of developing new VCFs than the groups treated with alendronate (P = .07), calcium (P = .05), selective estrogen receptor modulator (SERM) (P = .15), and risendronate (P = .02). This study showed that for patients with new VCFs after KP, lower BMD, greater intradiscal cement leakage, greater KA recovery rate, and lower baseline vertebral height were likely risk factors for the development of new VCFs. Additionally, among the drugs used for the treatment of osteoporosis after KP, zoledronate tends to reduce the development of new VCFs compared with other bisphosphonates, SERMs, or calcium.

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.

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.

Can facet joint block be a complementary or alternative therapeutic option for patients with osteoporotic vertebral fractures: a meta-analysis

Background

Recently facet joint block has been increasingly used to relief the residual pain after vertebral augmentation, but whether it can be a complementary or alternative to vertebral augmentation remain largely unknown. Thus, we conducted this meta-analysis to determine the effect of facet joint block in the treatment of osteoporotic vertebral compression fractures (OVCF).

Methods

Following PRISMA statement, a comprehensive literature search through Embase, PubMed, Web of Science, Wanfang Data, China National Knowledge Infrastructure and Chinese BioMedical Literature Database was performed to identify relevant studies. Studies comparing vertebral augmentation combined with facet joint block (combined therapy) with vertebral augmentation, and studies comparing facet joint block with vertebral augmentation were analyzed, respectively.

Results

A total of 10 studies were included. There were seven studies comparing combined therapy with vertebral augmentation, the results showed combined therapy was associated with significantly lower visual analog scale (VAS) scores on postoperative day 1, 7, month 1, 3, and lower oswestry disability index (ODI) scores on postoperative day 1, 7, and month 3. There were three studies comparing facet joint block with vertebral augmentation, the results demonstrated vertebral augmentation only provided better analgesia in month 1 after surgery, but it was associated with a higher incidence of refracture.

Conclusions

Current evidence suggested facet joint block might be considered as a complementary to vertebral augmentation in the treatment of OVCF, but it might not be effectively used as an alternative therapy.

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.

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.

Does prophylactic vertebral augmentation reduce the refracture rate in osteoporotic vertebral fracture patients: a meta-analysis

PURPOSE

In order to prevent the recurrent fracture after vertebral augmentation, the concept of prophylactic vertebral augmentation has been proposed, but its efficacy is still controversial. This study aimed to determine the efficacy of prophylactic vertebral augmentation for prevention of refracture in osteoporotic vertebral fracture patients.

METHODS

Following PRISMA guidelines, a literature search was performed using PubMed, Embase and Web of Science databases for relevant studies published until February 2021. A meta-analysis of randomized controlled trials and retrospective controlled trials comparing prophylactic group versus nonprophylactic group was conducted. The primary outcome was the incidence of new vertebral compression fracture (VCF), and secondary outcomes were incidence of adjacent vertebral fracture (AVF) and remote vertebral fracture (RVF).

RESULTS

A total of 6 studies encompassing 618 patients were included in the meta-analysis. The incidence of new VCF was reported in all six studies, and the result showed no significant difference between the two groups (OR: 0.509; 95% CI: 0.184-1.409). Four studies provided data on the incidence of AVF, and it was revealed that there was no significant difference between the two groups (OR: 0.689; 95% CI: 0.109-4.371). In view of the incidence of RVF, prophylactic group also did not differ significantly compared with nonprophylactic group (OR: 0.535; 95% CI: 0.167-1.709).

CONCLUSIONS

The current evidence suggested that prophylactic vertebral augmentation might not be appropriate to diminish the risk of new VCF. Therefore, there is a need to investigate the mechanism of refracture and explore other preventive regimens to reduce the risk.

Percutaneous Vertebroplasty Does Not Increase the Incidence of New Fractures in Adjacent and Nonadjacent Vertebral Bodies

STUDY DESIGN

This was a clinical retrospective study.

OBJECTIVES

This retrospective study aimed to investigate the incidence of new vertebral compression fractures (NVCFs) and analyze the risk factors that influence the secondary fractures in adjacent and nonadjacent levels after percutaneous vertebroplasty (PVP) and conservative treatment (CT).

SUMMARY OF BACKGROUND DATA

PVP is an effective procedure to alleviate the pain caused by osteoporotic vertebral compression fractures. NVCFs have been noted as a potential late sequela of the procedure. However, it remains unclear whether NVCFs are due to this augmentation or simply are the result of the natural progression of osteoporosis.

METHODS

A total of 290 patients who had undergone PVP and 270 patients who had undergone CT during the last 4 years were examined. They were followed-up on a monthly basis by telephone for >2 years. They were divided into 2 groups: NVCFs and non-NVCFs. The groups were statistically compared in terms of age, sex, body mass index, initial fracture levels, bone mineral density (BMD) score of the spine, original fracture levels, and new fracture levels.

RESULTS

After a mean follow-up of at least 24 months (range, 24-78 mo), 42 NVCFs occurred in 37 of 290 patients after PVP and 33 NVCFs in 30 of 270 patients after CT. Only BMD was significantly different between the groups. Lower BMD was a significant predictive factor for NVCFs.

CONCLUSIONS

PVP did not increase the incidence of NVCFs, especially those adjacent to the treated vertebrae, following augmentation with PVP compared with CT. The most important risk factor for NVCFs was osteoporosis.

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.

Coronal Imaging Changes Associated with Recollapse of Injured Vertebrae After Percutaneous Vertebroplasty or Percutaneous Kyphoplasty Treatment for Osteoporotic Thoracolumbar Fracture

OBJECTIVE

To observe coronal imaging changes associated with recollapse of injured vertebrae after percutaneous vertebroplasty or percutaneous kyphoplasty for osteoporotic thoracolumbar fracture (OTLF).

METHODS

Fifty-four cases were retrospectively divided into 2 groups according to the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) classification of thoracolumbar fracture: group A, type A1 fracture (n = 26); group B, type A3.1 fracture (n = 28). Visual analog scale, Oswestry Disability Index, local scoliotic Cobb angle, and coronal wedge angle of the injured vertebrae were observed preoperatively, on postoperative day 3, and at final follow-up.

RESULTS

The average follow-up time was 19.17 ± 6.30 months. At final follow-up, the visual analog scale score and the Oswestry Disability Index score were significantly greater in group B than in group A (both P < 0.05). At final follow-up, loss of correction of scoliotic Cobb angle and coronal wedge angle was significantly higher in group B than in group A (P < 0.05).

CONCLUSIONS

Percutaneous vertebroplasty or percutaneous kyphoplasty was effective in both type A1 and type A3.1 OTLF. However, coronal imaging changes after percutaneous vertebroplasty or percutaneous kyphoplasty were more obvious in type A3.1 OTLF than in type A1. Moreover, clinical outcomes in type A3.1 OTLF were slightly inferior to those in type A1.

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.

The positive correlation between upper adjacent vertebral fracture and the kyphosis angle of injured vertebral body after percutaneous kyphoplasty: An in vitro study

OBJECTIVE

To investigate the correlation between the kyphosis angle of injured vertebral body and the risk of upper adjacent vertebral fracture after percutaneous kyphoplasty (PKP) using an osteoporotic vertebral compressed fracture model.

MATERIALS AND METHODS

24 functional spinal units (FSUs, T9 to L4) were selected from 6 elderly formalin preserved vertebral specimens to build the vertebral compressed fracture model. According to the kyphosis angle between the upper plate of upper vertebral body and the horizontal plane, group A (0°) and group B (20°) were defined, with each group comprised with 12 FSUs. The stiffness and fracture load were measured in both groups.

RESULTS

After PKP, the stiffness was (571.513 ± 83.373)N/mm and the fracture load was (1751.659 ± 112.291)N in group A, with both significantly higher than those of group B (stiffness, (307.706 ± 46.723)N/mm; fracture load, (1128.011 ± 125.417)N).

CONCLUSIONS

To reduce the risk of upper adjacent vertebral fracture, it is better to restore the height of injured vertebral body and decrease the angle of kyphosis to increase the capability of upper adjacent vertebral body against fracture.

The clinical effect of percutaneous kyphoplasty for the treatment of multiple osteoporotic vertebral compression fractures and the prevention of new vertebral fractures

This study aimed to investigate the clinical effect of percutaneous kyphoplasty and the precautions against adjacent vertebral refractures in the treatment of multiple osteoporotic vertebral compression fractures. 54 cases (128 vertebrae) with multiple osteoporotic vertebral compression fractures from July 2007 to December 2013 treated with percutaneous kyphoplasty were retrospectively reviewed. 36 cases of them suffered from bi-segment vertebral fractures, 16 cases with tri-segment vertebral fractures and 2 cases with quadri-segment vertebral fractures. The operative effect was evaluated by visual analogue scale (VAS) score and oswestry disability index (ODI) score. Then the reasons for adjacent vertebral refractures were analyzed and the precautions were proposed. 54 cases (128 vertebrae) were admitted with percutaneous kyphoplasty successfully. No pulmonary embolism, spinal cord injury and other serious complications were found. The follow-up took 3-33 months with the average of 12 months. There was significant difference of VAS scores and ODI scores between pre-operation and post-operation (P<0.05). Bone cement leakage occurred in 23 vertebrae, and the incidence rate was 18.0%. 8 cases sustained adjacent vertebral refractures including 3 cases in the contiguous vertebral bodies and 5 cases in the interval vertebral bodies, and the incidence rate was 14.8%. 5 cases gained fracture healing after additional percutaneous kyphoplasty procedures while the other 3 cases were healed basically after conservative treatment for three months. In conclusion, percutaneous kyphoplasty is safe and effective to treat multiple osteoporotic vertebral compression fractures. However, the risk of new adjacent vertebral fractures in the multiple osteoporotic vertebral compression fractures is higher than that in the single osteoporotic vertebral compression fracture. Timely and proper treatment can reduce refractures.

Cement leakage in percutaneous vertebroplasty for spinal metastases: a retrospective evaluation of incidence and risk factors

STUDY DESIGN

Retrospective assessment of risk factors using univariate and multivariate analyses.

OBJECTIVE

To evaluate risk factors retrospectively for cement leakage (CL), including vascular cement leakage (vCL) and cortical cement leakage (cCL), in percutaneous vertebroplasty of spinal metastasis.

SUMMARY OF BACKGROUND DATA

Complications of vertebroplasty for spine metastasis are rare but related to extravertebral cement leakage that is pulmonary embolism and medullary compression. Better understanding of the risk factors for vascular and cortical types of cement leakage is necessary to prevent these complications.

METHODS

Fifty-six cancer patients (30 females, 26 males; age, 56 ± 12 yr) (81 vertebrae) were treated in 58 sessions under fluoroscopy or computed tomography-fluoroscopy guidance. Leakage rates were reported. The following items were assessed for occurrence of CL, vCL, and cCL: primary tumor site, prior radiotherapy or local tumor ablation or embolization, appearance on computed tomography, cortical osteolytic destruction, vertebral collapse, operator's experience, guidance modality, and cement filling.

RESULTS

CL, vCL, and cCL rates were 53%, 25%, and 32%. History of prior treatment correlated with a decrease in CL (P = 0.018). vCL decreased when lung was the primary tumor site (P = 0.036), in osteolytic vertebrae (P = 0.033) or when there was a vertebral collapse (P = 0.037). cCL correlated with operator's experience (P = 0.021) and vertebral collapse (P < 0.001). Superior discal cCL correlated with superior endplate cortical destruction (P = 0.012). Although history of prior treatment seemed to be an independent protective factor (odds ratio = 0.24; 95% confidence interval, 0.087-0.7; P = 0.001), vertebral collapse was isolated as a risk factor for cCL (odds ratio = 32; 95% confidence interval, 6.7-161; P = 0.001).

CONCLUSION

Risk factors for cCL and vCL are distinct. Vertebral collapse and cortical destruction are risk factors for cCL. History of prior treatment is a protective factor for CL.

LEVEL OF EVIDENCE

4.

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.