Can anti-osteoporotic therapy reduce adjacent fracture in magnetic resonance imaging-proven acute osteoporotic vertebral fractures?

Space between bone cement and bony endplate can trigger higher incidence of augmented vertebral collapse: An in-silico study

BACKGROUND

The pathogenesis of postoperative complications in patients with osteoporotic vertebral compressive fractures (OVCFs) undergoing percutaneous vertebroplasty (PVP) is multifaceted, with local biomechanical deterioration playing a pivotal role. Specifically, the disparity in stiffness between the bone cement and osteoporotic cancellous bone can precipitate interfacial stress concentrations, potentially leading to cement-augmented vertebral body collapse and clinical symptom recurrence. This study focuses on the biomechanical implications of the space between the bone cement and bony endplate (BEP), hypothesizing that this interface may be a critical locus for stress concentration and subsequent vertebral failure.

METHODS

Leveraging a validated numerical model from our previous study, we examined the biomechanical impact of the cement-BEP interface in the L2 vertebral body post-PVP, simulated OVCF and PVP and constructed three distinct models: one with direct bone cement contact with both cranial and caudal BEPs, one with contact only with the caudal BEPs and one without contact with either BEP. Moreover, we assessed stress distribution across cranial and caudal BEPs under various loading conditions to describe the biomechanical outcomes associated with each model.

RESULTS

A consistent trend was observed across all models: the interfaces between the bone cement and cancellous bone exhibited higher stress values under the majority of loading conditions compared to models with direct cement-BEP contact. The most significant difference was observed in the flexion loading condition compared to the mode with direct contact between BEP and cement. The maximum stress in models without direct contact increased by at least 30%.

CONCLUSIONS

Our study reveals the biomechanical significance of interfacial stiffness differences at the cement-BEP junction, which can exacerbate local stress concentrations and predispose to augmented vertebral collapse. We recommend the strategic distribution of bone cement to encompass a broader contact area with the BEP for preventing biomechanical failure and subsequent vertebral collapse.

Comparative analysis of anti-osteoporosis medications in preventing vertebral body fractures after balloon kyphoplasty

This retrospective study compared the efficacy of anabolic agents (romosozumab and teriparatide) with that of alendronate in preventing subsequent vertebral body fractures (SVBFs) after balloon kyphoplasty (BKP). All anabolic agents significantly reduced SVBFs. Romosozumab was most effective in increasing bone mineral density (BMD) and completely suppressed distant vertebral body fractures.

INTRODUCTION

To determine optimal anti-osteoporosis medications, we compared romosozumab and teriparatide to alendronate as a control from perioperative BKP to the 1st postoperative year for treatment and secondary fracture prevention in osteoporosis.

METHODS

A total of 603 patients who underwent initial BKP for osteoporotic vertebral fractures were evaluated and categorized into five groups based on drug administration: romosozumab (group R, 155 patients), twice-weekly teriparatide (group TW, 48), weekly teriparatide (group W, 151), daily teriparatide (group D, 138), and alendronate (control) (group C, 111). The 1-year incidence of SVBFs, BMD change rate, and probability of requiring BKP were compared among the groups.

RESULTS

SVBF incidence was 3.9%, 6.5%, 8.3%, 6.0%, and 14.4% in groups R, D, TW, W, and C, respectively, with all other groups exhibiting significantly lower rates than group C. The groups that administered the anabolic agents had a notably lower incidence of distant fractures than group C. Compared with group C, group R showed significantly higher BMD change rates in lumbar vertebral bodies at 4, 8, and 12 months and group D at 12 months. Anabolic agent groups exhibited significantly higher improvement rates than group C after conservative treatment alone.

CONCLUSION

The anabolic agents were found to be more effective at reducing the incidence of SVBF (especially distant vertebral fractures) than alendronate. These agents decreased the rate of repeat BKP even after the occurrence of a fracture. Overall, the use of an anabolic agent for the treatment of osteoporosis after BKP is better than the use of alendronate, even when treatment is initiated in the perioperative stage.

The cranial vertebral body suffers a higher risk of adjacent vertebral fracture due to the poor biomechanical environment in patients with percutaneous vertebralplasty

BACKGROUND CONTEXT

Adjacent vertebral fracture (AVF), a frequent complication of PVP, is influenced by factors such as osteoporosis progression, increased intervertebral cement leakage (ICL), and biomechanical deterioration. Notably, the risk of AVF is notably elevated in the cranial vertebral body compared with the caudal counterpart. Despite this knowledge, the underlying pathological mechanism remains elusive.

PURPOSE

This study delves into the role of biomechanical deterioration as a pivotal factor in the heightened risk of AVF in the cranial vertebral body following PVP. By isolating this variable, we aim to unravel its prominence relative to other potential risk factors.

STUDY DESIGN

A retrospective study and corresponding numerical mechanical simulations.

PATIENT SAMPLE

Clinical data from 101 patients treated by PVP were reviewed in this study.

OUTCOME MEASURES

Clinical assessments involved measuring Hounsfield unit (HU) values of adjacent vertebral bodies as a representation of patients' bone mineral density (BMD). Additionally, the rates of ICL were compared among these patients. Numerical simulations were conducted to compute stress values in the cranial and caudal vertebral bodies under various body positions.

METHODS

In a retrospective analysis of PVP patients spanning July 2016 to August 2019, we scrutinized the HU values of adjacent vertebral bodies to discern disparities in BMD between cranial and caudal regions. Additionally, we compared ICL rates on both cranial and caudal sides. To augment our investigation, well-validated numerical models simulated the PVP procedure, enabling the computation of maximum stress values in cranial and caudal vertebral bodies across varying body positions.

RESULTS

The incidence rate of cranial AVF was significantly higher than the caudal side. No notable distinctions in HU values or ICL rates were observed between the cranial and caudal sides. The incidence of AVF showed no significant elevation in patients with ICL in either region. However, numerical simulations unveiled heightened stress values in the cranial vertebral body.

CONCLUSIONS

In patients postPVP, the cranial vertebral body faces a heightened risk of AVF, primarily attributed to biomechanical deterioration rather than lower BMD or an elevated ICL rate.

Is Teriparatide Superior in Treating Osteoporotic Vertebral Compression Fractures in Comparison to Bisphosphonates Treatment Alone: A 2-Year Retrospective Analysis

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to compare the efficacy of bisphosphonates and teriparatide in the management of osteoporotic vertebral compression fractures with regard to pain management, prevention of nonunion, and radiological as well as clinical outcomes.

OVERVIEW OF LITERATURE

Osteoporosis refers to a skeletal disorder characterized by decreased bone strength caused by poor bone density and quality causing fragility, resulting in long periods of pain-related immobilization.

METHODS

In a 24-month follow-up retrospective study, 191 patients with osteoporotic vertebral compression fractures were randomly assigned to the bisphosphonate group (n=104) or the teriparatide group (n=87), with patients opting for their treatment between January 2016 and October 2020. Demographic data and patient-reported outcomes scores, including the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), union rates, and kyphosis progression, were assessed at baseline, 6 months, 1 year, and 2 years after treatment.

RESULTS

Both groups had a significant decrease in VAS, from 8.38±0.74 to 3.15±1.40 in the bisphosphonate group and from 8.49±0.73 to 1.11±0.31 in the teriparatide group. The ODI scores reduced significantly at 2-year follow-ups, recording 25.02±13.94 and 15.11±2.17 in the bisphosphonate and teriparatide groups, respectively. Risks of nonunion development were slightly higher at 11.53% in the bisphosphonate group and 8.63% in the teriparatide group required operative intervention. The kyphosis progression angles were also significantly lower in the teriparatide group (4.97°±0.78°) than in the bisphosphonate group (8.09°±1.25°).

CONCLUSIONS

Over time, numerous studies have demonstrated the efficacy of bisphosphonates and teriparatide in ameliorating pain. In this study, the efficacy of teriparatide surpassed that of bisphosphonates in certain aspects, such as the initial 6-month union rates and reduction in the progression of segmental kyphosis. However, bisphosphonates and teriparatide yield similar and favorable union rates at 1 year and final follow-up.

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.

The vertebral Hounsfield units can quantitatively predict the risk of adjacent vertebral fractures after percutaneous kyphoplasty

Background

Measuring the Hounsfield units (HU) of the vertebrae may yield diagnostic information for fracture risk. This study aimed to measure HU of vertebrae in percutaneous kyphoplasty (PKP) patients using computed tomography (CT) imaging to determine the HU measurements threshold for adjacent vertebral fracture and to assess the relationship between HU measurements and the risk of adjacent vertebral fracture.

Methods

A retrospective study was conducted on consecutive patients who underwent PKP between January 2019 and October 2021 in the China-Japan Union Hospital of Jilin University. The HU of the vertebra was measured on the reconstructed CT images by 2 independent spine surgeons. The HU measurements of adjacent vertebrae and the ratio of HU measurements between the surgical vertebra and adjacent vertebrae were statistically analyzed to determine the best critical value and evaluate the prediction effectiveness and accuracy of the best critical value.

Results

A total of 105 patients were identified with complete imaging and follow-up information. Of these, 47 patients (44.8%) had evidence of an adjacent vertebral fracture on follow-up imaging. The mean HU measurements of the fractured adjacent vertebra were significantly different from the mean HU measurements of the unfractured adjacent vertebra (50.94±20.59 vs. 81.74±18.97 HU; P<0.001). There was a significant difference in the ratio of HU measurements between the surgical vertebra and the fractured adjacent vertebra and between the surgical vertebra and the unfractured adjacent vertebra (26.34±17.52 vs. 14.53±9.40; P<0.001). Interactive scatter plots and receiver operating characteristic (ROC) curve showed that a HU measurement of 66.9 and a HU measurements ratio of 15.18 were the best thresholds for predicting the risk of fracture of adjacent vertebrae after PKP surgery, with an area under the curve (AUC) of 0.901 [95% confidence interval (CI): 0.822-0.953; P<0.001] and 0.874 (95% CI: 0.790-0.934; P<0.001), respectively. The prediction accuracy was 90.4% and 84.0%, respectively.

Conclusions

A low mean HU measurements of adjacent vertebrae or a high ratio of the mean HU measurements of the operated vertebrae to the adjacent vertebrae are risk factors for the vulnerability of adjacent vertebrae to fracture. The risk of fracture in the adjacent vertebrae after PKP can be predicted by measuring HU.

Timing of symptomatic subsequent vertebral compression fracture associated with different demographic factors

BACKGROUND

Symptomatic subsequent vertebral compression fracture (VCF; SVCF) is a common complication associated with poor outcomes. Accumulating evidence shows that demographic factors and incidences of symptomatic SVCFs differ during different periods after the primary vertebroplasty (VP).

PURPOSE

To investigate the incidence and demographic factors of symptomatic SVCFs after the primary VP in different periods using registry data in the Taiwan National Health Insurance Research Database.

METHODS

This retrospective cohort study included 28,343 patients aged ≥ 50 years with painful VCF treated with VP from 2002 to 2016. Symptomatic SVCF was defined as SVCF requiring another VP or re-admission. During the 2-year follow-up, 1955 patients received subsequent VP while 1,407 were readmitted. Cox proportional hazard models were used to compare the risks of subsequent VP or readmission.

RESULTS

The cumulative incident rate of subsequent VP and re-hospitalization was 0.87 [95% confidence interval (CI), 0.82 ~ 0.92] and 0.62 (95% CI, 0.58 ~ 0.66) per 100 person-months, respectively, within the first 6 months after the primary VP, and it decreased over time. A multiple Cox regression model showed that age, osteopenia or osteoporosis, Charlson comorbidity index (CCI) were significant independent risk factors of subsequent VP or readmission within the first 6 months.

CONCLUSIONS

This study demonstrated that the incidence of symptomatic SVCF peaked in the first 6 months after the primary VP. Age, osteoporosis or osteopenia, and CCI were determined to be risk factors in the first 6 months, but only osteoporosis or osteopenia and CCI were risk factors thereafter.

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.

Vertebral augmentation reduces the 12-month mortality and morbidity in patients with osteoporotic vertebral compression fractures

OBJECTIVES

To investigate the 12-month all-cause mortality and morbidity in patients with osteoporotic vertebral compression fractures (OVCFs) undergoing vertebroplasty/balloon kyphoplasty (VP/BKP) versus non-surgical management (NSM).

METHODS

Following a Medline and EMBASE search for English language articles published from 2010 to 2019, 19 studies reporting on mortality and morbidity after VP/BKP in patients with OVCFs were selected. The 12-month timeline was set due to the largest amount of data availability at such time interval. Estimates for each study were reported as odds ratios (OR) along with 95% confidence intervals (CI) and p values. Fixed or random-effects meta-analyses were performed. All tests were based on a two-sided significance level of 0.05.

RESULTS

Pooled OR across 5 studies favored VP/BKP over NSM in terms of 12-month all-cause mortality (OR: 0.81 [95% CI: 0.46-1.42]; p = .46). Pooled OR across 11 studies favored VP/BKP over NSM in terms of 12-month all-cause morbidity (OR: 0.64 [95% CI: 0.31-1.30]; p = .25). Sub-analysis of data dealing with 12-month infective morbidity from any origin confirmed the benefit of VP/BKP over NSM (OR: 0.23 [95% CI, 0.02-2.54]; p = .23).

CONCLUSION

Compared to NSM, VP/BKP reduces the 12-month risk of all-cause mortality and morbidity by 19% and 36%, respectively. Moreover, VP/BKP reduces by 77% the 12-month risk of infection from any origin.

KEY POINTS

• Compared to non-surgical management, vertebral augmentation reduces the 12-month risk of all-cause mortality by 19% and all-cause morbidity by 36%. • Vertebral augmentation reduces the 12-month risk of infection morbidity from any origin by 77%.

Effect of bisphosphonates or teriparatide on mechanical complications after posterior instrumented fusion for osteoporotic vertebral fracture: a multi-center retrospective study

Background

The optimal treatment of osteoporosis after reconstruction surgery for osteoporotic vertebral fractures (OVF) remains unclear. In this multicentre retrospective study, we investigated the effects of typically used agents for osteoporosis, namely, bisphosphonates (BP) and teriparatide (TP), on surgical results in patients with osteoporotic vertebral fractures.

Methods

Retrospectively registered data were collected from 27 universities and affiliated hospitals in Japan. We compared the effects of BP vs TP on postoperative mechanical complication rates, implant-related reoperation rates, and clinical outcomes in patients who underwent posterior instrumented fusion for OVF. Data were analysed according to whether the osteoporosis was primary or glucocorticoid-induced.

Results

A total of 159 patients who underwent posterior instrumented fusion for OVF were included. The overall mechanical complication rate was significantly lower in the TP group than in the BP group (BP vs TP: 73.1% vs 58.2%, p = 0.045). The screw backout rate was significantly lower and the rates of new vertebral fractures and pseudoarthrosis tended to be lower in the TP group than in the BP group. However, there were no significant differences in lumbar functional scores and visual analogue scale pain scores or in implant-related reoperation rates between the two groups. The incidence of pseudoarthrosis was significantly higher in patients with glucocorticoid-induced osteoporosis (GIOP) than in those with primary osteoporosis; however, the pseudoarthrosis rate was reduced by using TP. The use of TP also tended to reduce the overall mechanical complication rate in both primary osteoporosis and GIOP.

Conclusions

The overall mechanical complication rate was lower in patients who received TP than in those who received a BP postoperatively, regardless of type of osteoporosis. The incidence of pseudoarthrosis was significantly higher in patients with GIOP, but the use of TP reduced the rate of pseudoarthrosis in GIOP patients. The use of TP was effective to reduce postoperative complications for OVF patients treated with posterior fusion.

The Clinical Effect of Kyphoplasty Using the Extrapedicular Approach in the Treatment of Thoracic Osteoporotic Vertebral Compression Fracture

BACKGROUND

To evaluate the clinical effect of kyphoplasty with the extrapedicular approach in the treatment of thoracic osteoporotic compression fractures, including upper, middle, and lower thoracic.

METHODS

From April 2014 to December 2016, 50 cases (55 vertebrae) of thoracic osteoporotic fractures were treated with balloon kyphoplasty using the extrapedicular approach. Symptomatic levels ranged from T3 to T12 and were confirmed based on medical history, physical examination, and medical imaging. Pain relief, restoration of vertebral anterior and median height, and kyphosis correction were retrospectively compared before and after operation by using the visual analogue scale and radiography, respectively. In addition, bone cement leakage location and complications were recorded.

RESULTS

Operations were successfully performed in all the cases, with an average surgery time of 77 minutes and follow-up period of 15 months (range, 6-36 months). The visual analogue scale scores at 3 days after operation and final follow-up were significantly reduced (P < 0.05). The vertebral anterior margin and median height on radiography after surgery were significantly improved (P < 0.05), and the kyphosis was significantly corrected. Four cases had cement leakage but no other adverse events. No blood vessel or spinal cord puncture injury during surgery or blood vessel embolism, pulmonary embolism, or fat embolism after surgery was found.

CONCLUSIONS

Extrapedicular kyphoplasty is safe and effective in treating thoracic osteoporotic vertebral compression fractures. It can rapidly relieve backache, restore the body height of the fractured thoracic vertebra, and correct kyphosis. In addition, it can improve patient quality of life.

[Low cement distribution index is a risk factor for refracture of the adjacent segments after percutaneous vertebroplasty]

OBJECTIVE

To investigate the impact of cement distribution index on the occurrence of refracture in the adjacent segments after percutaneous vertebroplasty.

METHODS

This retrospective analysis was conducted among 143 patients who received percutaneous vertebroplasty for osteoporotic vertebral compression fracture between April, 2011 and April, 2014. Of the 134 patients with complete follow-up data, 18 had adjacent segment fracture within 1 year following the surgeries (re-fracture group), and 116 patients without new fracture served as the control group. All the patients underwent X-ray examinations after the surgery and according to the position and shape, the cement in the vertebrae were classified into 5 types (I to V), and the volume-cubage index was computed based on the cement volume and vertebral cubage. Age, gender, bone mineral density (BMD), cement distribution index, volume-cubage index, and cement leakage were evaluated in the 2 groups, and the variables with significant differences between the 2 groups were analyzed in Logistic regression analysis.

RESULTS

BMD was significantly lower and the rate of cement leakage was significantly higher in the re-fracture group than in the control group (P<0.05). Significant difference was found in cement distribution index between the 2 groups (P<0.05) but not in age, gender, cement volume or volume-cubage index (P>0.05). Logistic regression analysis indicated that BMD, cement leakage and cement distribution index all significantly affected the occurrence of adjacent vertebral fractures following percutaneous vertebroplasty.

CONCLUSION

A low BMD, cement leakage and a low cement distribution index are all risks factor of adjacent vertebral fracture after percutaneous vertebroplasty.