Effect of Bone Cement Volume Fraction on Adjacent Vertebral Fractures After Unilateral Percutaneous Kyphoplasty

Modified versus conventional percutaneous kyphoplasty for osteoporotic vertebral compression fracture treatment: a systematic review and pilot meta-analysis

PURPOSE

This study compares the safety and clinical effectiveness of modified percutaneous kyphoplasty (PKP) approaches (transverse process-pedicle or extrapedicular) with the conventional transpedicular approach for treating osteoporotic vertebral compression fractures.

METHODS

We searched various databases, including PubMed, Cochrane Library, Web of Science, Embase, and Scopus. Safety outcomes included operative time, radiation dose, injected cement volume, and cement leakage rate, while efficacy outcomes were the Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Cobb's angle, and vertebral body height. The quality of cohort studies was assessed using the Newcastle-Ottawa Score, and a meta-analysis was conducted using Review Manager 5.4.

RESULTS

Nine high-quality cohort studies involving 1,187 patients were included. Compared to conventional PKP, the modified approach resulted in significantly shorter operative time (mean differences [MD]: - 11.72, 95% confidence interval [CI]: - 16.56 to - 6.88, p < 0.00001), lower radiation dose (standardized mean differences: - 2.21, 95% CI: - 2.96 to - 1.45, p < 0.00001), reduced injected cement volume (MD: - 0.89, 95% CI: - 1.58 to - 0.21, p = 0.01), and a lower cement leakage rate (MD: 0.58, 95% CI: 0.41-0.80, p = 0.001). However, both groups had no significant differences in VAS score, ODI score, Cobb's angle, or vertebral body height.

CONCLUSION

No significant difference in pain relief or functional improvement was observed between modified and conventional PKP. However, modified PKP has a shorter operative time, a lower radiation dose, a lower injected cement volume, and a lower cement leakage rate than conventional PKP. These findings suggest that modified PKP is safer, with similar therapeutic outcomes to conventional PKP.

Poor bony density can independently trigger higher incidence of adjacent vertebral fracture after percutaneous vertebralplasty: a mono-center retrospective study

OBJECTIVE

Symptomatic adjacent vertebral fractures (AVF) poses a challenge to patient prognosis in osteoporotic vertebral compressive fractures (OVCF) treated by percutaneous vertebralplasty (PVP). This study aimed to identify potential risk factors for AVF, thereby offering theoretical insights for refining patient management strategies and surgical protocols.

METHODS

Clinical data of PVP patients treated between March 2018 and May 2020 were retrospectively analyzed, with an average follow-up period of 30 months. Patients were stratified into two groups based on the presence or absence of recurrent symptomatic AVF. Demographic characteristics and imaging based parameters were assessed to identify potential risk factors for AVF.

RESULTS

Demographic parameters, including age, sex, body mass index, and fracture location (junctional or non-junctional), did not significantly differ between the two groups and were not found to be independent risk factors for AVF. However, patients with AVF exhibited significantly lower bone mineral density, as assessed by T-score and Hounsfield unit (HU) values. Notably, lower HU values emerged as an independent risk factor for AVF. Contrary to expectations, larger vertebral distraction and intervertebral disc cement leakage did not trigger higher incidence of AVF.

CONCLUSION

Progression of bony density reduction emerged as the primary driver for the heightened incidence of AVF. Accordingly, anti-osteoporosis therapy should be regarded as an effective strategy for mitigating the risk of AVF in patients undergoing PVP.

What Risk Factors Are Associated With Recurrent Osteoporotic Vertebral Compression Fractures After Percutaneous Vertebral Augmentation? A Meta-analysis

BACKGROUND

Osteoporotic vertebral compression fracture (OVCF) has been extensively treated clinically using percutaneous vertebral augmentation (PVA), which includes percutaneous kyphoplasty and percutaneous vertebroplasty. Postoperative refracture is a common complication after PVA, but the associated factors and specific mechanisms behind these fractures are not entirely clear.

QUESTIONS/PURPOSES

In a systematic review and meta-analysis, we asked: What factors were associated with increased or decreased odds of refracture after PVA for OVCF?

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines, we conducted a comprehensive search of the Cochrane Library, PubMed, Web of Science, and Embase for the time period from database inception to August 31, 2024 (which also was when we last searched). We included case-control studies in which participants were patients with OVCF and were treated with PVA, grouped into refracture versus non-refracture groups based on the presence or absence of refracture. We excluded studies published on preprint servers, conference reports, case reports, and systematic reviews or meta-analyses. We collected 2398 records in the database. After excluding studies that were duplicates and did not meet the inclusion criteria, we included 22 studies involving 7132 participants, 75% (5368) of whom were women, with a mean age of 76 years for patients in the refracture group and 74 years for patients in the non-refracture group. Quality assessment was performed using the Newcastle-Ottawa Scale, with which we assessed three aspects of the study; the mean ± SD score for the included studies was 7.3 ± 0.7 of 9 total (on this scale, higher scores are better), representing generally high study quality. The determination of heterogeneity relied on I2 and chi-square test, and we used a random-effects model when the I2 was > 50% and p ≤ 0.05; otherwise, a fixed-effects model was chosen. According to the Egger test and trim and fill method, publication bias did not significantly affect most of our results.

RESULTS

The combined results showed that older age (mean difference 2.24 [95% confidence interval (CI) 1.25 to 3.23]; p < 0.001), lower bone mineral density (BMD) (standardized mean difference [SMD] -0.72 [95% CI -0.99 to -0.45]; p < 0.001), greater preoperative AP vertebral height ratio (SMD 0.26 [95% CI 0.07 to 0.45]; p = 0.01), greater preoperative kyphotic angle (KA) (SMD 0.47 [95% CI 0.10 to 0.83]; p = 0.01), bone cement leakage (OR 1.39 [95% CI 1.05 to 1.84]; p = 0.02), multivertebral fractures (OR 3.58 [95% CI 2.53 to 5.07]; p < 0.001), smoking (OR 1.53 [95% CI 1.16 to 2.02]; p = 0.003), use of glucocorticoids (OR 3.18 [95% CI 2.09 to 4.84]; p < 0.001), and previous osteoporotic vertebral fracture (OR 2.55 [95% CI 1.58 to 4.13]; p < 0.001) were associated with increased odds of refractures after surgery. Use of antiosteoporosis therapy was associated with a decreased odds of postoperative refracture (OR 0.39 [95% CI 0.24 to 0.64]; p < 0.001).

CONCLUSION

Based on the results of our meta-analysis, surgeons can identify those who are more likely to have refracture by knowing basic information about their patients preoperatively, such as advanced age, lower BMD, greater preoperative AP ratio, greater preoperative KA, and the presence of multivertebral fractures or previous osteoporotic vertebral fracture. Also, intraoperative reduction of bone cement leakage and postoperative counseling of patients to quit smoking, reduce glucocorticoid use, and administration of antiosteoporosis therapy were used to reduce the probability of refracture. The association between some factors and refracture is uncertain, such as BMI and thoracolumbar fracture, and further studies are needed.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Contact between leaked cement and adjacent vertebral endplate induces a greater risk of adjacent vertebral fracture with vertebral bone cement augmentation biomechanically

BACKGROUND CONTEXT

Adjacent vertebral fracture (AVF) is a frequently observed complication after percutaneous vertebroplasty in patients with osteoporotic vertebral compressive fracture (OVCF). Studies have demonstrated that intervertebral cement leakage (ICL) can increase the incidence of AVF, but others have reached opposite conclusions. The stress concentration initially increases the risk of AVF, and dispersive concentrated stress is the main biomechanical function of the intervertebral disc (IVD).

PURPOSE

This study was designed to validate the hypothesis that direct contact between the leaked cement and adjacent bony endplate (BEP) can inhibit this biomechanical function, trigger adjacent vertebral stress concentration and increase the risk of AVF.

STUDY DESIGN

A retrospective study and corresponding numerical mechanical simulations.

PATIENT SAMPLE

Clinical data from 97 OVCF patients treated by bone cement augmentation operations were reviewed in this study.

OUTCOME MEASURES

Clinical assessments involved measuring ICL and cement-BEP contact status in patients with and without AVF. Numerical simulations were conducted to compute stress values in adjacent vertebral body's BEP and cancellous bone under various body positions.

MATERIALS AND METHODS

Radiographic and demographic data of 97 OVCF patients (with an average follow-up period of 11.5 months) treated using bone cement augmentation operation were reviewed in the present study. The patients were divided into 2 groups: those with AVF and those without AVF. Bone cement leakage status was judged via 2 different methods: with or without IVD cement leakage and with and without adjacent vertebral endplate contact. The data from patients with and without AVF were compared, and the independent risk factors were identified through regression analysis. Patients without IVD cement leakage, with IVD cement leakage but without adjacent vertebral endplate cement contact, and with direct adjacent vertebral endplate cement contact were simulated using a previously constructed and validated lumbar finite element model, and the biomechanical indicators related to the AVF were computed and recorded in these surgical models.

RESULTS

Radiographic analysis revealed that the incidence of AVF was numerically higher, but was not significantly higher in patients with IVD cement leakage. In contrast, patients with direct adjacent vertebral endplate cement contact had a significantly greater incidence of AVF, which has also been proven to be an independent risk factor for AVF. In addition, numerical mechanical simulations revealed an obvious stress concentration tendency (the higher maximum equivalent stress value) in the adjacent vertebral body in the model with endplate cement contact.

CONCLUSIONS

Direct adjacent vertebral endplate cement contact induces a greater risk of AVF through deterioration of the local biomechanical environment. Cement injection, therefore, should be terminated when IVD cement leakage occurs to reduce adjacent vertebral endplate cement contact and reduce the resulting risk of AVF biomechanics.

Tripod-Fix device for the treatment of painful osteoporotic vertebral compression fractures

Current vertebral augmentation procedures (VAPs) often involve devices associated with bone cement leakage. Tripod-Fix is designed to mitigate the risk of bone cement leakage by expanding in three dimensions to fit a narrower vertebral space. This study enrolled 12 patients diagnosed with osteoprorotic vertebral compression fractures (VCFs) for 12 month follow up. The primary outcomes assessed were changes in the Visual Analog Score (VAS) and Oswestry Disability Index (ODI) before and after treatment. Our results demonstrated significant pain relief with VAS decreasing from 8.58 ± 1.83 to 2.75 ± 1.54 cm and improved mobility with ODI decreasing from 73.67 ± 16.29 to 31.83 ± 23.33% post-treatment and sustained for 12 months. Follow-up radiographs revealed no device-related adverse events such as cement leakage, vertebral body collapse, or adjacent vertebral fractures (AVFs). In addition, the mean anterior height restoration ratio after treatment was 15.87 ± 5.13%. Our preliminary findings suggest that Tripod-Fix exhibits safety and efficacy comparable to the third-generation devices currently utilized for treating osteoporotic VCFs.

Development and validation of a prediction model for vertebral recompression and adjacent vertebral fracture after kyphoplasty in geriatric patients

PURPOSE

Short-term efficacy of percutaneous kyphoplasty (PKP) for treating osteoporotic vertebral compression fracture (OVCF) in elderly patients is good, but long-term complications such as vertebral recompression (VRC) and adjacent vertebral fracture (AVF) may arise. Identifying risk factors in patients with poor prognoses, we developed a nomogram model to mitigate these potential complications.

METHODS

Patients with OVCFs who underwent PKP had their medical data retrospectively evaluated. Analysis of the sample included their pre- and postoperative conditions. Stepwise logistic regression analyses were conducted to identify independent risk factors for postoperative complications. For forecasting the likelihood of postoperative comorbidities, we offered a nomogram. The prognostic performance was assessed using the receiver operating characteristic curve (ROC), calibration curve, and decision curve analyses (DCA). Internal model validation using the Bootstrap method.

RESULTS

A total of 235 patients were included in this study. Among them, 147 patients were utilized to develop nomograms and for internal validation, while the remaining 88 patients from a different time period were designated as the external validation cohort. The results of stepwise logistic regression analysis showed that thoracolumbar (TL) fracture, posterior wall of vertebral fracture, vertebral compression > 30%, and lack of continuous anti-osteoporosis therapy after surgery as independent risks associated with poor prognosis. The nomogram exhibited outstanding predictive accuracy and clinical utility.

CONCLUSIONS

This study identified four independent predictors of poor prognosis following PKP and devised a straightforward yet efficient predictive model. This model offers valuable insights for guiding clinical decision-making in the management of elderly patients with OVCFs.

Analysis of injected cement volume and clinical outcomes following balloon-assisted kyphoplasty in a series of 368 patients

OBJECTIVE

Balloon-assisted kyphoplasty (BAK) is a modified vertebroplasty technique developed to treat vertebral compression fractures (VCFs) secondary to osteoporosis. This study investigates the association between injected cement volume and the development of subsequent VCFs after BAK.

METHODS

A retrospective analysis of 368 patients who underwent BAK at a single institution was performed from 2001 to 2021. Inclusion was defined by at least 2 years of follow-up. Clinical characteristics and outcomes following BAK, including subsequent fractures at adjacent and remote levels, were identified. Patients that underwent a thoracic BAK were stratified by injected cement volume: below or equal to the median (≤ 6.0 mL, 265 vertebrae) or above the median (> 6.0 mL, 144 vertebrae). Patients that underwent a lumbar BAK were similarly stratified: below or equal to the median (≤ 8.0 mL, 233 vertebrae) or above the median (>8.0 mL, 160 vertebrae).

RESULTS

A total of 802 vertebrae were treated. The average volume of cement was recorded in the thoracic (6.2 ± 1.9 mL) and lumbar (7.8 ± 1.8 mL) vertebrae. In the thoracic spine, vertebrae that were injected with > 6.0 mL of cement underwent a greater change in local kyphotic angle (P = 0.0001) and were more likely to develop adjacent-level VCFs (P = 0.032) after kyphoplasty. Univariate analysis did not elucidate any additional risk factors. There were no statistical differences in clinical outcomes between the three groups of lumbar vertebrae.

CONCLUSIONS

Larger volumes of injected cement were associated with a greater change in local kyphosis and subsequent adjacent-level fractures after BAK in the thoracic spine. This association was not found in the lumbar spine. Close attention to injected cement volumes must be made in the thoracic spine and patients who undergo significant kyphotic correction should be carefully observed postoperatively.

Computed Tomography Volumetry of Bone Cement: Retrospective Blinded Validation of Commercially Available Semi-automated Edge Detection Software

OBJECTIVE

Cement volumes are increasingly linked to orthopedic oncology and neurosurgical outcomes (construct durability, adjacent fracture), but manual cement volumetry remains time prohibitive. The authors aim to report performance of PACS-integrated volumetric software specifically for barium-enhanced polymethylmethacrylate cement.

METHODS

Institutional review board-approved single-institution retrospective review of patients from 2019-2022 undergoing kyphoplasty for pathological compression fractures with a quantitative cement infuser providing true cement volume. An operator blinded to true cement volumes retrospectively performed software-assisted volumetry on follow-up computed tomography scans.

RESULTS

Included were 91 kyphoplasty levels in 56 patients: mean age, 62 years (range, 34-85 years), 73% female. True cement volume (available for 44 of 66 procedures) was mean 4.5 mL per level (range, 1.2-15.6 mL). Measured cement volume (available for all procedures) yielded a mean of 6.1 mL per level (range, 1.5-27.9 mL). For the 57 levels (39 patients) where both true and measured cement volumes were available, linear regression intercept and slope were 1.46 (95% CI = 0.97-1.95, P < 0.001) and 0.52 (CI = 0.47-0.57, P < 0.001), respectively, suggesting measured volume averaged 1.46 mL greater than true volume, with each additional milliliter of measured volume corresponding to approximately 0.52 mL of true volume. There was no significant difference in the relationship between estimated and actual cement volume in thoracic levels (intercept = -0.24, CI = -1.13 to 0.66, P = 0.61; slope = 0.03, CI = -0.14 to 0.19, P = 0.73) compared with lumbar levels. The goodness-of-fit of the regression model was strong ( R2 = 0.81). Discrepancies ranged from 90% underestimation to 52% overestimation; average, 17% overestimation.

CONCLUSIONS

Semi-automated volumetry maintained a strong correlation with true volumes across the thoracic and lumbar curvatures, overestimating cement volume by a mean of 17% or 1.46 mL.

Risk Factors of New Symptomatic Fractures After Vertebroplasty: A Retrospective Cohort Study of 268 Patients with Painful Osteoporotic Vertebral Compression Fracture

OBJECTIVE

To evaluate the risk factors of new osteoporotic vertebral compression fractures (OVCFs) after percutaneous vertebroplasty (PVP).

METHODS

From January 2016 to November 2019, patients suffering from OVCFs were retrospectively reviewed. The independent influence factors for new OVCFs after PVP were assessed, from following variables: age, sex, body mass index, bone mineral density (BMD), history of alcoholism, smoking, hypertension, diabetes, glucocorticoid use, and prior vertebral fractures, the number of initial fractures, mean cement volume, method of puncture, D-type of cement leakage, and regular antiosteoporosis treatment.

RESULTS

A total of 268 patients with 347 levels met the inclusion criteria and were finally included in this study. Forty-nine levels of new OVCFs among 33 patients (12.31%) were observed during the follow-up period. It indicated that female (adjusted odds ratio [OR]: 6.812, 95% confidence interval {CI}: [1.096, 42.337], P = 0.040), lower BMD (adjusted OR: 0.477, 95% CI: [0.300, 0.759], P = 0.002), prior vertebral fractures (adjusted OR: 16.145, 95% CI: [5.319, 49.005], P = 0.000), and regular antiosteoporosis treatment (adjusted OR: 0.258, 95% CI: [0.086, 0.774], P = 0.016) were independent influence factors for new OVCF. The cut-off value of BMD to reach new OVCF was -3.350, with a sensitivity of 0.660 and a specificity of 0.848.

CONCLUSION

Female, lower BMD (T-score of lumbar), prior vertebral fractures, and regular antiosteoporosis treatment were independent influencing factors. BMD (T-score of lumbar) lower than -3.350 would increase risk for new OVCF, and none osteoporotic treatment has detrimental effect on new onset fractures following PVP.

Predicting osteoporotic fractures post-vertebroplasty: a machine learning approach with a web-based calculator

PURPOSE

The aim of this study was to develop and validate a machine learning (ML) model for predicting the risk of new osteoporotic vertebral compression fracture (OVCF) in patients who underwent percutaneous vertebroplasty (PVP) and to create a user-friendly web-based calculator for clinical use.

METHODS

A retrospective analysis of patients undergoing percutaneous vertebroplasty: A retrospective analysis of patients treated with PVP between June 2016 and June 2018 at Liuzhou People's Hospital was performed. The independent variables of the model were screened using Boruta and modelled using 9 algorithms. Model performance was assessed using the area under the receiver operating characteristic curve (ROC_AUC), and clinical utility was assessed by clinical decision curve analysis (DCA). The best models were analysed for interpretability using SHapley Additive exPlanations (SHAP) and the models were deployed visually using a web calculator.

RESULTS

Training and test groups were split using time. The SVM model performed best in both the training group tenfold cross-validation (CV) and validation group AUC, with an AUC of 0.77. DCA showed that the model was beneficial to patients in both the training and test sets. A network calculator developed based on the SHAP-based SVM model can be used for clinical risk assessment ( https://nicolazhang.shinyapps.io/refracture_shap/ ).

CONCLUSIONS

The SVM-based ML model was effective in predicting the risk of new-onset OVCF after PVP, and the network calculator provides a practical tool for clinical decision-making. This study contributes to personalised care in spinal surgery.

Changes of inflammatory cytokines in vertebral compression fractures patients with percutaneous balloon kyphoplasty

Objective: To explore the changes of a series of cytokines before and after percutaneous balloon kyphoplasty (PKP) and prognostic markers for response to PKP.Methods: From 1 January 2019 to 31 May 2019, all single-level lumbar osteoporotic vertebral compression fracture (OVCF) patients diagnosed by MRI who matched the inclusion and exclusion criteria were enrolled in this study. They were classified into the effective group and the ineffective group based on the outcome after PKP. The levels of a series of inflammatory factors and indices of spinal functions were obtained before and after PKP.Results: A total of 72 patients were included in this study, 59 in the effective group and 13 in the ineffective group. The anterior height (AH) and posterior height (PH) were 77.3 ± 11.2% and 91.2 ± 9.3%, respectively, in the effective group after PKP, which were higher than that in the ineffective group (p<.001). While, the Kyphotic angle, visual analog scale (VAS), and Oswestry Disability Index (ODI) score were 9.1 ± 4.3°, 3.1 ± 1.9, and 19.2 ± 4.1 in the effective group, which was lower than that in ineffective group (p<.001). The serum levels of IL-1β, IL-6, and TNF-α were found significantly decreased after treatment in the effective group (p<.05). The logistic regression showed that the levels of IL-6 TNF-α and AH were significant predictor of outcome.Conclusions: Our results demonstrated that PKP can reduce the serum levels of IL-6, IL-1β, and TNF-α, moreover, the IL-6, TNF-α, and AH were significant predictors of outcome.

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.

Bipedicular percutaneous kyphoplasty versus unipedicular percutaneous kyphoplasty in the treatment of asymmetric osteoporotic vertebral compression fractures: a case control study

BACKGROUND

Bipedicular/unipedicular percutaneous kyphoplasty are common treatments for OVCF, and there are no studies to show which is more beneficial for AVCF. The purpose of this study was to investigate the clinical efficacy of BPKP or UPKP in the treatment of AVCF.

METHODS

The clinical data of AVCF patients treated by PKP were retrospectively analyzed. They were divided into two groups according to the surgical approach. General demographic data, perioperative complications, and general information related to surgery were recorded for both groups. The preoperative and postoperative vertebral height difference, vertebral local Cobb angle, lumbar pain VAS score and lumbar JOA score were counted for both groups. The above data were compared preoperatively, postoperatively and between the two groups.

RESULTS

25 patients with AVCF were successfully included and all were followed up for at least 12 months, with no complications during the follow-up period. 10 patients in the BPKP group and 15 patients in the UPKP group, with no statistically significant differences in general information between the two groups. The VAS scores of patients in the BPKP group were lower than those in the UPKP group at 12 months after surgery, and the differences were statistically significant, and there were no statistically significant differences between the two groups at other follow-up time points. In the BPKP group, 80% of patients had symmetrical and more homogeneous bone cement dispersion. 50% of patients in the UPKP group had a lateral distribution of bone cement and uneven bone cement distribution, and the difference in bone cement distribution between the two groups was statistically significant.

CONCLUSION

For the treatment of AVCF, the clinical efficacy of both surgical approaches is basically the same. The distribution of cement is more symmetrical and uniformly diffused in the BPKP group, and the clinical efficacy VAS score is lower in the long-term follow-up. Bipedicular percutaneous kyphoplasty is recommended for the treatment of AVCF.

THE ETHICAL REVIEW BATCH NUMBER

XZXY-LJ-20161208-047.

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

BACKGROUND

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

METHODS

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

CONTROL GROUP

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

RESULTS

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

PRIMARY OUTCOME

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

SECONDARY OUTCOMES

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

CONCLUSIONS

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

Comparative evaluation of an innovative deflectable percutaneous kyphoplasty versus conventional bilateral percutaneous kyphoplasty for osteoporotic vertebral compression fractures: a prospective, randomized and controlled trial

BACKGROUND CONTEXT

Osteoporotic vertebral compression fractures (OVCFs) can be treated with percutaneous kyphoplasty (PKP). In contrast to conventional PKP, the novel deflectable percutaneous kyphoplasty (DPKP), is a unilateral transpedicular approach procedure allowing a similar bilateral puncture effect, which owes to the deflectable curved bone expander creating a transcentral line cavity to achieve uniform distribution of cement and biomechanical balance while reducing operative time and radiation exposure.

PURPOSE

The purpose of this study was to prospectively compare and evaluate an innovative surgical procedure, DPKP, versus conventional bilateral percutaneous kyphoplasty (BPKP).

STUDY DESIGN

This is a prospective randomized controlled trial (RCT).

SAMPLE

The totality of the participants (n=90) suffering from OVCFs between May 2019 and October 2020, were randomized by SAS 9.3 to generate a block randomization sequence, which was utilized to randomize the groups in a 1:1 ratio, assigned to the DPKP group (n=45) and the BPKP group (n=45) to undergo accordingly procedures.

OUTCOME MEASURES

The primary outcome was the total operative time. The secondary outcomes included: comparative assessment of visual analog scale (VAS) scores, Oswestry disability index (ODI), kyphosis angle (KA), anterior border height (AH) of the injured vertebra, frequency of intraoperative X-ray fluoroscopy, the injection volume, distribution pattern and leakage rate of bone cement.

METHODS

All subjects underwent assessment by at least one senior orthopedist and radiologist for the VAS scores, ODI, KA, AH of the injured vertebra, total operative time, the injection volume, distribution pattern, leakage rate of bone cement at preoperative and 24 hours, 6 months, and 1 year postoperatively. Inclusion criteria for subjects in this prospective study were as follows: (1) 60 < age < 80 years old; (2) preoperative spinal X-ray, CT, and MRI confirmed as single-segment, fresh thoracolumbar OVCFs (T5-L5, 15% < collapse < 80%); MRI shows low signal on T1-WI and high signal on T2-WI, especially with STIR high signal characterized by vertebral edema; (3) painful OVCFs refractory to medical treatment, 2 weeks < Symptom duration < 3 months;(4) With significant physical signs of local tenderness; (5) T score of bone mineral density (BMD) < -2.5.

RESULTS

The total operative time was significantly reduced in the DPKP group (43.3±19.58 minutes, 95% CI: 37.23-49.37) compared to the BPKP group (55.16±11.56 minutes, 95% CI: 51.78-58.54) (p<.001). Compared to the BPKP group (frequency of intraoperative X-ray fluoroscopy: 43.42±8.64, 95% CI: 40.90-45.95; the volume of bone cement injected: 5.56±0.85 mL, 95% CI: 5.31-5.81), the frequency of intraoperative X-ray fluoroscopy (30.05±17.41, 95% CI: 24.66-35.45) and volume of bone cement injected (5.08±0.97 mL, 95% CI: 4.78-5.38) significantly reduced in the DPKP group compared to the (p<.001). In addition, compared to the preoperative period, both groups showed significant improvements in the postoperative VAS scores, ODI, KA, and AH (p<.001), but there was no statistical difference between the DPKP and BPKP groups (p>.05) at any time-point. Interestingly, although without statistical differences, a tendency towards a lower rate of bone cement leakage was observed in the DPKP group.

CONCLUSION

Our study results indicate that the innovative DPKP is as safe and effective as BPKP in relieving pain, improving the patient's quality of life, and reconstructing vertebral body height. Particularly, DPKP did reduce operative time and radiation exposure compared to BPKP, which correlated with unilateral and bilateral exposure procedures. Moreover, the final cement distribution was less predictable in DPKP, and further studies are warranted to clarify the advantages of DPKP versus conventional unilateral percutaneous kyphoplasty (UPKP) and BPKP.

Bilateral percutaneous kyphoplasty achieves more satisfactory outcomes compared to unilateral percutaneous kyphoplasty in osteoporotic vertebral compression fractures: A comprehensive comparative study

BACKGROUND

Osteoporotic vertebral compression fractures (OVCFs) are the most common complication of osteoporosis, a worldwide disease that disturbs the elderly.

OBJECTIVE

The purpose of the study was to comprehensively compare the clinical efficacy of unilateral percutaneous kyphoplasty (UPKP) and bilateral percutaneous kyphoplasty (BPKP) when treating OVCFs and evaluate their ability to maintain the outcomes in a 2-year follow-up.

METHODS

From January 2015 to December 2016 a total of 79 patients with OVCFs were included in the study. They were divided into UPKP group and BPKP group. Subsequently, perioperative data, radiological outcomes, clinical outcomes, and complications were compared between two groups. The follow-up consultation was 3 months, 1 year, and 2 years after the operation.

RESULTS

37 of patients (14 males, 23 females) were allocated to the UPKP group and 42 patients (13 males, 29 females) were treated with BPKP. The duration of operation and injected cement volume were significantly higher in the BPKP group than those of the UPKP group. BPKP achieved significantly higher improvement in middle height and volume of the fractured vertebral body than UPKP did. There were significantly higher losses of anterior, middle height and volume of the fractured vertebral body in the UPKP group at 2-year follow-up than in the BPKP group. At the final follow-up, Oswestry Disability Index (ODI) of BPKP group was lower than that of UPKP group.

CONCLUSION

Both UPKP and BPKP achieve satisfactory radiological and clinical outcomes when treating OVCFs. However, in a 2-year follow-up, BPKP maintains vertebral height restoration, volume of vertebral body, and ODI better than UPKP do.

Incidence, Risk Factors, and Outcomes of Symptomatic Bone Cement Displacement following Percutaneous Kyphoplasty for Osteoporotic Vertebral Compression Fracture: A Single Center Study

STUDY DESIGN

Retrospective.

BACKGROUND

Symptomatic bone cement displacement (BCD) is a rare complication following percutaneous kyphoplasty (PKP) interventions for osteoporotic vertebral compression fracture (OVCF). This study aimed to investigate the incidence and the outcomes of symptomatic BCD comprehensively and identify its risk factors.

METHODS

The clinical data of patients treated with PKP for OVCF between January 2012 and December 2020 were extracted. Patients who developed BCD following PKP during follow-up were divided into the symptomatic and asymptomatic groups. Patients who did not develop BCD were assigned to the control group. Univariate and multiple logistic regression analyses were used to compare the three clinical groups' features to assess the independent risk factors for the symptomatic and asymptomatic groups.

RESULTS

A total of 896 patients were enrolled. Twenty-one patients (2.3%) were identified as having symptomatic BCD following PKP for OVCF, and 35 (3.9%) developed asymptomatic BCD. Compared with the control group, the symptomatic and asymptomatic groups had a higher incidence of anterior leakage, intravertebral vacuum cleft (IVC) signs, and a lower cement distribution score. The symptomatic group had a lower relative cross-sectional area (rCSA) of the paraspinal muscle (PSM), higher PSM fatty degeneration, and higher kyphotic angle (at the last follow-up) than the asymptomatic and control groups. For outcomes, the symptomatic group had a higher VAS/ODI score and a higher incidence of new vertebral fractures compared with the asymptomatic and control groups. Anterior leakage (OR: 1.737, 95% CI: 1.215-3.300), the IVC sign (OR: 3.361, 95% CI: 1.605-13.036), the cement distribution score (OR: 0.476, 95% CI: 0.225-0.904), PSM rCSA (OR: 0.953, 95% CI: 0.917-0.992), and PSM fatty degeneration (OR: 1.061, 95% CI: 1.005-1.119) were identified as independent risk factors for the symptomatic group. Anterior leakage (OR: 1.839, 95% CI: 1.206-2.803), the IVC sign (OR: 2.936, 95% CI: 1.174-9.018), and cement distribution score (OR: 0.632, 95% CI: 0.295-0.858) were independent risk factors for the asymptomatic group.

CONCLUSION

The incidence of symptomatic BCD is 2.3% in patients treated with PKP. Anterior leakage, the IVC sign, and the distribution score were independent risk factors for BCD, and paraspinal muscle degeneration was a specific risk factor for symptomatic BCD. Symptomatic BCD can lead to poor outcomes.

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.

A Comparison Between Modified Unilateral Extrapedicular and Bilateral Transpedicular Percutaneous Kyphoplasty in the Treatment of Lumbar Osteoporotic Vertebral Compression Fracture

BACKGROUND

Few researchers have verified the clinical efficacy and safety of the modified unilateral extrapedicular approach (mUEP) applied to the percutaneous kyphoplasty (PKP) in comparative studies with other puncture techniques. Compared with the bilateral transpedicular approach (BTP), whether mUEP PKP is a preferred treatment for lumbar osteoporotic vertebral compression fracture (OVCF) remains unclear.

METHODS

Patients treated by PKP for single-level lumbar OVCF in our institution from September 2019 to December 2020 were retrospectively enrolled. Patients were grouped according to the puncture techniques. Clinical and radiologic outcomes were evaluated preoperatively, postoperatively, and at follow-up. The clinical evaluation was performed by using visual analog scale for pain relief and Oswestry Disability Index for health status. Radiologic measurements contained anterior vertebral height, kyphotic angle, and bone cement distribution.

RESULTS

In total, 76 patients with a mean follow-up duration of 16.6 months were enrolled, including 34 patients in the mUEP PK group and 42 patients in the BTP PKP group. In the mUEP group, operation time, fluoroscopy times, and injected cement volume were significantly less than that in the BTP group (P < 0.01). Both visual analog scale and Oswestry Disability Index scores of all patients decreased significantly after surgery (P < 0.01), with no significant differences between the 2 groups at each follow-up. Both mUEP PKP and BTP PKP showed significant anterior height restoration and kyphotic angle correction (P < 0.01), with no significant differences between the 2 groups at each follow-up. Meanwhile, the mUEP PKP reduced the incidence of intraspinal cement leakage (P < 0.05), and no facet joint violation was found in mUEP PKP.

CONCLUSIONS

mUEP PKP could be clinically and radiographically equivalent to BTP PKP. However, it has advantages in reducing operation time and fluoroscopy times, lowering the risk of intraspinal cement leakage, and preventing the presence of facet joint violation. Compared with BTP PKP, the mUEP PKP seems to be an effective and alternative puncture technique for the treatment of lumbar OVCF after appropriate patient selection.

Risk factors of vertebral re-fracture after PVP or PKP for osteoporotic vertebral compression fractures, especially in Eastern Asia: a systematic review and meta-analysis

Objective

Percutaneous vertebroplasty (PVP) and kyphoplasty (PKP) have been widely used to treat osteoporotic vertebral compression fractures (OVCF), but the risk of vertebral re-fracture after PVP/PKP remains controversial. This study aims to investigate the incidence and risk factors of vertebral re-fracture after PVP/PKP.

Methods

Relevant literatures published up to November 2021 were collected from PubMed, Embase and Web of Science. A meta-analysis was performed to extract data associated with risk factors of SVCF following the PRISMA guidelines. Also, pooled odds ratio (OR) or weighted mean difference (WMD) with 95% confidence interval (CI) was calculated.

Results

A total of 23 studies, encompassing 9372 patients with OVCF, met the inclusion criteria. 1255 patients (13.39%) suffered re-fracture after PVP/PKP surgery. A total of 22 studies were from Eastern Asia and only 1 study was from Europe. Female sex (OR = 1.34, 95%CI 1.09–1.64, P = 0.006), older age (WMD = 2.04, 95%CI 0.84–3.24, P = 0.001), lower bone mineral density (BMD, WMD = − 0.38, 95%CI − 0.49–0.26, P < 0.001) and bone cement leakages (OR = 2.05, 95% CI 1.40–3.00, P < 0.001) increased the risk of SVCF. The results of subgroup analysis showed the occurrence of re-fracture was significantly associated with gender (P = 0.002), age (P = 0.001) and BMD (P < 0.001) in Eastern Asia. Compared with the unfractured group, anterior-to-posterior vertebral body height ratio (AP ratio, WMD = 0.06, 95%CI 0.00–0.12, P = 0.037) and visual analog scale score (VAS, WMD = 0.62, 95%CI 0.09–1.15, P = 0.022) were higher in the refracture group, and kyphotic angle correction ratio (Cobb ratio, WMD = − 0.72, 95%CI − 1.26–0.18, P = 0.008) was smaller in Eastern Asia. In addition, anti-osteoporosis treatment (OR = 0.40, 95% CI 0.27–0.60, P < 0.001) could be a protective factor.

Conclusion

The main factors associated with re-fracture after PVP/PKP are sex, age, bone mineral density, AP ratio, Cobb ratio, VAS score, bone cement leakage and anti-osteoporosis treatment, especially in Eastern Asia.

Early Percutaneous Vertebroplasty Improves Bone-Cement Integration and Reduces Adjacent Fractures

BACKGROUND

Percutaneous vertebroplasty (PVP) is widely used for treatment of osteoporotic vertebral compression fractures (VCFs). However, the influence of PVP timing (early vs. late) on development of adjacent vertebral fractures has rarely been discussed. This retrospective cohort study aimed to evaluate bone-cement binding for thoracolumbar fractures (T8-L3) using a new assessment method to predict risk for adjacent vertebral fractures.

METHODS

Patients with a single-level T-score ≤ -1.0 of lumbar bone mineral density and a primary osteoporotic VCF in the thoracolumbar region (T8-L3) who underwent PVP from October 2016 to February 2018 at our medical university-affiliated hospital were included. Patients were divided into refracture and non-refracture groups. All patients underwent computed tomography after vertebroplasty. Bone-cement distribution patterns were evaluated using standardized axial computed tomography images of each cemented vertebra by 4 independent observers with ImageJ software. The smoothness index was calculated as a percentage of smooth margins.

RESULTS

Of 51 VCFs, 15 (29.4%) and 36 (70.6%) were refracture and non-refracture VCFs, respectively. The mean smoothness index (MSI) was higher in the refracture group than in the non-refracture group (P < 0.01), with an increased refracture risk that corresponded to increased MSI values (P = 0.004). Spearman correlation coefficient (0.375) showed a positive correlation between the fracture-vertebroplasty interval and MSI (P = 0.01).

CONCLUSIONS

Axial computed tomography images were used to characterize bone-cement binding properties. Patients who underwent early PVP had a lower MSI, better bone-cement integration, and fewer adjacent fractures.

Analysis on the Effect of Different Surgical Methods on the Treatment of Senile Osteoporotic Spinal Compression Fractures and the Influencing Factors of Complications

Osteoporotic fractures are a common type of fractures in the elderly, among which spinal compression fractures are more common. After the occurrence of fractures, due to the compression and burst of the vertebral body, this will lead to local kyphosis deformity and even affect the balance of the sagittal spine. In the past, conservative treatments were used for osteoporotic spinal compression fractures. Although it can relieve pain symptoms, it can easily lead to complications such as aggravation of osteoporosis and deep vein thrombosis of the lower extremities. At present, percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) are the main clinical surgical treatments, both of which are minimally invasive surgery, short operation time, effective pain relief, and rapid postoperative recovery. Although both of them are effective, there is still controversy over the efficacy of both in the treatment of osteoporotic spinal compression fractures. The purpose of this study was to investigate the efficacy of PVP and PKP in the treatment of elderly osteoporotic spinal compression fractures and to analyze the related factors that affect the occurrence of postoperative complications. The results show that both PVP and PKP can effectively improve the pain and dysfunction of elderly patients with osteoporotic spinal compression fracture, restoration of vertebral height, and correct kyphosis, but PKP has better effect and higher safety and is worth promoting. Postoperative complications of patients are related to their age, bone mineral density, use of hormones, and antiosteoporosis treatment.

A randomized trial comparing the clinical efficacy and safety of a novel steerable percutaneous kyphoplasty with traditional PKP in osteoporotic vertebral fractures

Background

Percutaneous kyphoplasty (PKP) is a highly practical technology to treat osteoporotic vertebral compression fractures (OVCFs). However, the operation time and radiation exposure remain problematic. This study explored the differences in surgical effects and safety between a novel steerable percutaneous kyphoplasty (S-PKP) and traditional PKP in order to achieve better clinical outcomes for OVCF patients. It is also exploring whether the new technology could reduce the radiation exposure.

Methods

This study recruited 72 patients (between March 2019 and January 2020) with OVCFs (single vertebra). The patients were semi-randomly divided these patients into two groups according to ID numbers: a S-PKP group (33 cases) and a PKP group (39 cases). We evaluated the clinical efficacy using the kyphotic Cobb angle, Oswestry disability index (ODI), visual analogue scale (VAS) score, injected cement volume, operation time, intraoperative radiation times, bone cement leakage, and postoperative complications. Patients were followed up once preoperatively, and at 1 day, 6 months, and 1 year postoperatively.

Results

There were no cases of cement leakage or postoperative complications. There were no significant differences in gender, age, Bone mineral density T-score (BMD T) value, Cobb angle between the two groups (P>0.05). Intraoperative bone cement injection was approximately 5.25±1.37 and 5.32±1.29 mL in the PKP and S-PKP groups respectively. The postoperative VAS score and ODI of the two groups at 1 day, 6 months, and 1 year were markedly lower than before (P<0.05). There was a considerable improvement in the Cobb angle postoperatively (P<0.05). However, as the follow-up time extended, the Cobb Angle increased. The operation time and X-ray exposure times of patients in the PKP group were notably higher than those in the S-PKP group. The operation time was 51.59±9.14 min in the PKP group and 30.76±4.82 min in the S-PKP group. The frequency of intraoperative radiation was 105.9±31.93 times in the PKP group and 47.42±11.88 times in the S-PKP group.

Conclusions

Early results showed that S-PKP is a safe and efficient method for the treatment of OVCFs. S-PKP can reduce the operation time and radiation exposure.

Trial registration

Chinese Clinical Trial Registry ChiCTR2100046727

The Correlation Between the Diffusion Coefficient of Bone Cement and Efficacy in Percutaneous Vertebroplasty

This study investigated the effect of bone mineral density (BMD) on the diffusion coefficient (DC) of bone cement in percutaneous vertebroplasty (PVP) and the correlation between the DC and the efficacy after PVP. This was a retrospective study of PVP cases with follow-up longer than 12 months. The cases were assigned to 3 groups according to the BMD: BMD decrease group, osteoporosis group, and severe osteoporosis group. The 3 groups were compared regarding bone cement injection volume (IV), diffusion volume (DV), DC, visual analog scale (VAS) score, Oswestry Disability Index (ODI) score, and vertebral height loss ratio (VHLR). The correlation between DC and BMD, IV, DV, and VHLR was analyzed. The least significant difference test was used for comparison among the 3 groups, and the Pearson correlation coefficient was used for correlation analysis. There were a total of 132 cases, including 34 males and 98 females with a mean age of 76.5±9.6 years. The DV was larger than the IV in each group (P<.05). There was no statistically significant difference in the IV, VAS score, and ODI among the 3 groups (P>.05). However, there were significant differences in the DC and VHLR among the 3 groups (P<.05). Correlation analysis showed that there were significant correlations between BMD and IV (-0.716), BMD and DC (0.754), IV and DV (0.502), and IV and DC (-0.666) (P<.01). Scatter plot showed that the correlation between IV and BMD was r=0.716, R²=0.513, and the correlation between DC and BMD was r=0.754, R²=0.568. The DV was larger than the IV in PVP, and BMD was closely related to the DC. The higher the BMD, the higher the DC. Short-term follow-up revealed that the DC was inversely proportional to the VHLR. [Orthopedics. 2021;44(1):e95-e100.].

[Minimally invasive stabilization of thoracolumbar osteoporotic fractures]

BACKGROUND

Minimally invasive stabilization of thoracolumbar osteoporotic fractures (OF) in neurologically intact patients is well established. Various posterior and anterior surgical techniques are available. The OF classification and OF score are helpful for defining the indications and choice of operative technique.

OBJECTIVE

This article gives an overview of the minimally invasive stabilization techniques, typical complications and outcome.

MATERIAL AND METHODS

Selective literature search and description of surgical techniques and outcome.

RESULTS

Vertebral body augmentation alone can be indicated in painful but stable fractures of types OF 1 and OF 2 and to some extent for type OF 3. Kyphoplasty has proven to be an effective and safe procedure with a favorable clinical outcome. Unstable fractures and kyphotic deformities (types OF 3-5) should be percutaneously stabilized from posterior. The length of the pedicle screw construct depends on the extent of instability and deformity. Bone cement augmentation of the pedicle screws is indicated in severe osteoporosis but increases the complication rate. Restoration of stability of the anterior column can be achieved through additional vertebral body augmentation or rarely by anterior stabilization. Clinical and radiological short and mid-term results of the stabilization techniques are promising; however, the more invasive the surgery, the more complications occur.

CONCLUSION

Minimally invasive stabilization techniques are safe and effective. The specific indications for the individual procedures are guided by the OF classification and the individual clinical situation of the patient.

A novel and convenient method to evaluate bone cement distribution following percutaneous vertebral augmentation

A convenient method to evaluate bone cement distribution following vertebral augmentation is lacking, and therefore so is our understanding of the optimal distribution. To address these questions, we conducted a retrospective study using data from patients with a single-segment vertebral fracture who were treated with vertebral augmentation at our two hospitals. Five evaluation methods based on X-ray film were compared to determine the best evaluation method and the optimal cement distribution. Of the 263 patients included, 49 (18.63%) experienced re-collapse of treated vertebrae and 119 (45.25%) experienced new fractures during follow-up. A 12-score evaluation method (kappa value = 0.652) showed the largest area under the receiver operating characteristic curve for predicting new fractures (0.591) or re-collapse (0.933). In linear regression with the 12-score method, the bone cement distribution showed a negative correlation with the re-collapse of treated vertebra, but it showed a weak correlation with new fracture. The two prediction curves intersected at a score of 10. We conclude that an X-ray-based method for evaluation of bone cement distribution can be convenient and practical, and it can reliably predict risk of new fracture and re-collapse. The 12-score method showed the strongest predictive power, with a score of 10 suggesting optimal bone cement distribution.

How the clinical dosage of bone cement biomechanically affects adjacent vertebrae

Objective

This study evaluated the biomechanical changes in the adjacent vertebrae under a physiological load (500 N) when the clinically relevant amount of bone cement was injected into fractured cadaver vertebral bodies.

Methods

The embalmed cadaver thoracolumbar specimens in which each vertebral body (T12–L2) had a BMD of < 0.75 g/cm² were used for the experiment. For establishing a fracture model, the upper one third of the L1 vertebra was performed wedge osteotomy and the superior endplate was kept complete. Stiffness of specimens was measured in different states. Strain of the adjacent vertebral body and intervertebral disc were measured in pre-fracture, post-fracture, and after augmentation by non-contact optical strain measurement system.

Results

The average amount of bone cement was 4.4 ml (3.8–5.0 ml). The stiffness of after augmentation was significantly higher than the stiffness of post-fracture (p < 0.05), but still lower than pre-fracture stiffness (p < 0.05). After augmentation, the adjacent upper vertebral strain showed no significant difference (p > 0.05) with pre-fracture, while the strain of adjacent lower vertebral body was significantly higher than that before fracture (p < 0.05). In flexion, T12/L1 intervertebral disc strain was significantly greater after augmentation than after the fracture (p < 0.05), but there was no significant difference from that before the fracture (p > 0.05); L1/2 vertebral strain after augmentation was significantly less than that after the fracture (p < 0.05), but there was no significant difference from that before the fracture (p > 0.05).

Conclusions

PVP may therefore have partially reversed the abnormal strain state of adjacent vertebral bodies which was caused by fracture.

The effect of bone cement distribution on the outcome of percutaneous Vertebroplasty: a case cohort study

Background

To analyze the effect of different types of bone cement distribution after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fracture (OVCF).

Methods

One hundred thirty seven patients with single level OVCF who underwent PVP were retrospectively analyzed. The patients were divided into two groups according to bone cement distribution. Group A: bone cement contacted both upper and lower endplates; Group B: bone cement missed at least one endplate. Group B was divided into 3 subgroups. Group B1: bone cement only contacted the upper endplates; Group B2: bone cement only contacted the lower endplates; Group B3: bone cement only located in the middle of vertebral body. The visual analogue scale (VAS) score at 24 h post operation and last follow-up, anterior vertebral height restoration ratio (AVHRR), anterior vertebral height loss ratio (AVHLR), local kyphotic angle change and vertebral body recompression rate were compared.

Results

24 h post operation, the pain of all groups were significantly improved. The average follow-up time was 15.3 ± 6.3 (6–24) months. At last follow-up, the VAS score of group A was lower than that of group B. There were 14 cases (10.2%) of adjacent vertebral fracture, 5 cases (8.6%) in group A and 9 cases (11.4%) in group B. There were 9 cases (6.6%) of cement leakage, 4 cases (6.9%) in group A and 5 cases (6.3%) in group B. At last follow-up, there were 16 cases (11.7%) of vertebral body recompression, including 3 cases (5.2%) in group A and 13 cases (16.5%) in group B. There was no significant difference in AVHRR between two groups. Local kyphotic angle change was significant larger in group B. At last follow-up, AVHLR in group B was higher than that in group A. Analysis in subgroup B revealed no significant difference in VAS score, local kyphotic angle change, vertebral recompression rate, AVHRR or AVHLR.

Conclusions

If the bone cement fully contacted both the upper and lower endplates, it can better restore the strength of the vertebral body and maintain the height of the vertebral body, reduce the risk of the vertebral body recompression and long-term pain.

Tough and injectable fiber reinforced calcium phosphate cement as an alternative to polymethylmethacrylate cement for vertebral augmentation: a biomechanical study

Vertebral compression fractures (VCFs) are a very common problem among the elderly, which ultimately result in severe pain and a drastically reduced quality of life. An effective treatment for VCFs is the minimally invasive augmentation of the damaged vertebrae through vertebroplasty and/or kyphoplasty. These surgical procedures treat the affected vertebrae by injection of poly(methyl methacrylate) cement (PMMA) into the vertebral body. However, clinical use of PMMA cement is associated with major drawbacks. Bioceramic cements such as injectable calcium phosphate cements (CPC) exhibit a superior osteocompatibility over PMMA cements, but are too brittle for load-bearing applications. Here, we evaluated the handling and mechanical properties of a recently developed CPC formulation containing both poly(vinyl alcohol) (PVA) fibers and carboxymethyl cellulose (CMC) as an alternative to PMMA cement for vertebro- and kyphoplasty. Our results demonstrate that the addition of CMC rendered fiber-reinforced CPC injectable without negatively affecting its mechanical properties. Further, an ex vivo mechanical analysis clearly showed that extravasation of PVA fiber-reinforced CPC with CMC into trabecular bone was limited as compared to PMMA. Finally, we observed that the ex vivo biomechanical performance of vertebrae treated with CMC and PVA fibers was similar to PMMA-treated vertebrae. The obtained data suggests that PVA fiber-reinforced CPCs with CMC possesses adequate handling, mechanical and structural characteristics for vertebro- and kyphoplasty procedures. These data pave the way for future preclinical studies on the feasibility of treating vertebral compression fractures using PVA fiber-reinforced CPC with CMC.

Kyphoplasty for occult and non-occult osteoporotic vertebral fractures: a retrospective study

Objective

To compare the safety and efficacy of kyphoplasty in the treatment of occult and non-occult osteoporotic vertebral compression fractures (OOVF).

Material and Methods

From 2015 to 2017, 82 OOVF and 105 non-occult osteoporotic vertebral compression fractures (N-OOVF) were evaluated with the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and vertebral height preoperatively, immediately postoperatively, and one year postoperatively. Operative time, fluoroscopy time, and cement injection volume were recorded.

Results

Compared with the preoperative VAS and ODI scores, the scores of both groups were significantly improved after surgery. Preoperative ODI and VAS scores of the OOVF were lower than those of the N-OOVF. The operative time, fluoroscopy time, and bone cement injection volume of the OOVF were significantly lower than those of the N-OOVF. Vertebral height of the N-OOVF improved significantly after surgery. There were differences in cement leakage and adjacent vertebral fractures between the two groups.

Conclusion

Compared with N-OOVF, OOVF are safer with kyphoplasty, and it is necessary to diagnose OOVF in a timely manner.

Computational comparison of bone cement and poly aryl-ether-ether-ketone spacer in single-segment posterior lumbar interbody fusion: a pilot study

Posterior lumbar interbody fusion (PLIF) with a spacer and posterior instrument (PI) via minimally invasive surgery (MIS) restores intervertebral height in degenerated disks. To align with MIS, the spacer has to be shaped with a slim geometry. However, the thin spacer increases the subsidence and migration after PLIF. This study aimed to propose a new lumbar fusion approach using bone cement to achieve a larger supporting area than that achieved by the currently used poly aryl-ether-ether-ketone (PEEK) spacer and assess the feasibility of this approach using a sawbone model. Furthermore, the mechanical responses, including the range of motion (ROM) and bone stress with the bone cement spacer were compared to those noted with the PEEK spacer by finite element (FE) simulation. An FE lumbar L3-L4 model with PEEK and bone cement spacers and PI was developed. Four fixing conditions were considered: intact lumbar L3-L4 segment, lumbar L3-L4 segment with PI, PEEK spacer plus PI, and bone cement spacer plus PI. Four kinds of 10-NM moments (flexion, extension, lateral bending, and rotation) and two different bone qualities (normal and osteoporotic) were considered. The bone cement spacer yielded smaller ROMs in extension and rotation than the PEEK spacer, while the ROMs of the bone cement spacer in flexion and lateral bending were slightly greater than with the PEEK spacer. Compared with the PEEK spacer, peak contact pressure on the superior surface of L4 with the bone cement spacer in rotation decreased by 74% (from 8.68 to 2.25 MPa) and 69.1% (from 9.1 to 2.82 MPa), respectively, in the normal and osteoporotic bone. Use of bone cement as a spacer with PI is a potential approach to decrease the bone stress in lumbar fusion and warrants further research.

The effect of bone cement distribution on clinical efficacy after percutaneous kyphoplasty for osteoporotic vertebral compression fractures

To evaluate the influence of various distributions of bone cement on the clinical efficacy of percutaneous kyphoplasty (PKP) in treating osteoporotic vertebrae compression fractures.A total of 201 OVCF patients (30 males and 171 females) who received PKP treatment in our hospital were enrolled in this study. According to the characteristic of cement distribution, patients were divided into 2 groups: group A ("H" shaped group), the filling pattern in vertebral body were 2 briquettes and connected with / without cement bridge; and group B ("O" shaped group), the filling pattern in vertebral body was a complete crumb and without any separation. Bone mineral density, volume of injected cement, radiographic parameters, and VAS scores were recorded and analyzed between the 2 groups.All patients finished at least a 1-year follow-up and both groups had significant improvement in radiographic parameters and clinical results. No significant differences in BMD, operation time, bleeding volume, or leakage of cement were observed between the 2 groups. Compared with group B, group A had a larger use of bone cement, lower proportion of unipedicular approach, and better VAS scores at 1 year after surgery.Both "H" and "O" shaped distribution pattern can improve radiographic data and clinical outcomes effectively. However, "H" shaped distribution can achieve better clinical recovery at short-term follow-up.

Risk Factors of Secondary Vertebral Compression Fracture After Percutaneous Vertebroplasty or Kyphoplasty: A Retrospective Study of 650 Patients

Background

In this study, we aimed to investigate the risk factors contributing to secondary vertebral compression fractures (SVCF) in patients undergoing percutaneous vertebroplasty (PVP) or kyphoplasty (PKP) due to osteoporotic vertebral compression fracture (OVCF).

Material/Methods

Between January 2010 and December 2017, 650 patients with regular follow-up were identified and retrospectively analyzed in this study. Of these patients, 410 patients underwent PVP and 240 patients underwent PKP surgery. Patients were followed for 24 months on average, ranging from 6 months to 36 months follow-up. Possible risk factors screened for were age, gender, regional distribution, outdoor activity (ODA), bone mineral density (BMD), surgical methods (unilateral or bilateral), bone cement dose, bone cement leakage, chronic disease history, postoperative anti-osteoporosis treatment, and level of preoperative OVCF. Logistic regression analysis was applied to determine potential risk factors.

Results

As a result, 102 patients (15.7%) suffered SVCF after PVP/PKP surgery at the last follow-up. Binary logistic regression model showed that older age increased the risk of developing SVCF [odds ratio (OR)=2.48, P=0.031] while high-level BMD (OR=0.31, P<0.001) and ODA (OR=0.38, P=0.001) decreased the risk. Binary logistic regression model showed the following: Logit (P)=1.03+0.91X₁–1.18X₂–0.97X₃ (X₁=age, OR=2.48, P=0.031; X₂=BMD, OR=0.31, P<0.001; X₃=ODA, OR=0.38, P=0.001).

Conclusions

In conclusion, older age and lower BMD were identified as risk factors of SVCF for OVCF patients following PVP/PKP surgery, whereas more ODA played a protective role in SVCF development.

Kambin triangle approach in percutaneous vertebroplasty for the treatment of osteoporotic vertebral compression fractures

The aim of this study was to evaluate the safety and efficacy of percutaneous vertebroplasty (PVP) in Kambin triangle approach for the treatment of osteoporotic vertebral compression fractures (OVCFs).Between November 2017 and September 2018, 109 patients (144 vertebral bodies) with OVCFs, with a mean age of 76.7 ± 9.9 years (55-96 years), underwent PVP in Kambin triangle approach. The time of operation, the volume of bone cement, the incidence of complication, the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) score, the position of puncture needles, and the spread of polymethylmethacrylate (PMMA) in vertebral body (VB) were recorded.All patients had been completed the operation successfully and were followed up 9.1 ± 2.9 months. The average operation time of each VB was 24.0 ± 3.5 minutes. The average volume of cement was 4.8 ± 0.6 ml. The mean VAS scores were 8.4 ± 0.7 preoperatively, 1.6 ± 0.6 at the first day postoperatively, and 1.2 ± 0.6 at the last follow-up. The mean ODI scores were 70.97 ± 7.73 preoperatively, 27.99 ± 4.12 at the first day postoperatively, and 19.65 ± 3.49 at the last follow-up. The position of puncture needles in the VB was: 119 vertebral puncture needles reached the midline, 15 were close to the midline, and 10 exceeded the midline. The spread of PMMA in the VB was: type 1 in 81 levels (56.3%), type 2 in 37 (25.7%), type 3 in 18 (12.5%), type 5 in 8 (5.5%), and no case in type 4. One case developed pneumothorax after operation. No other complications (hematoma, cement embolism, spinal cord, and nerve injury) occurred.Kambin triangle approach in PVP, which can deliver the puncture needle to the midline of VB easily and with excellent cement distribution, is a safe and effective method.

Biomechanical evaluation of calcium phosphate-based nanocomposite versus polymethylmethacrylate cement for percutaneous kyphoplasty

BACKGROUND CONTEXT

Polymethylmethacrylate (PMMA) is the most commonly used filling material when performing percutaneous kyphoplasty (PKP) for the treatment of osteoporotic vertebral compression fractures. However, there are some inherent and unavoidable drawbacks with the clinical use of PMMA. PMMA bone cement tends to leak during injection, which can lead to injury of the spinal nerves and spinal cord. Moreover, the mechanical strength of PMMA-augmented vertebral bodies is extraordinary and this high level of mechanical strength might predispose to adjacent vertebral fractures. A novel biodegradable calcium phosphate-based nanocomposite (CPN) for PKP augmentation has recently been developed to potentially avoid these issues.

PURPOSE

By comparison with PMMA, the leakage characteristics, biomechanical properties, and dispersion of CPN were evaluated when used for PKP.

STUDY DESIGN

Biomechanical evaluation and studies on the dispersion and anti-leakage properties of CPN and PMMA cements were performed and compared using cadaveric vertebral fracture model, sheep vertebral fracture model, and simulated rigid foam model.

METHODS

Sheep vertebral bodies were decalcified by ethylenediaminetetraacetic acid disodium salt (EDTA-Na₂) to simulate osteoporosis in vitro. After compression to create wedge-shaped fractures using a self-designed fracture creation tool, human cadaveric vertebrae and decalcified sheep vertebrae were augmented by PKP. In addition, three L5 vertebral bodies from human cadavers were used in a contrast vertebroplasty (VP) augmentation experiment. Occurrence of cement leakage was observed and compared between CPN and PMMA during the process of vertebral augmentation. Open-cell rigid foam model (Sawbones#1522-507) was used to create a simulated leakage model for the evaluation of the leakage characteristics of CPN and PMMA with different viscosities. The augmentation effects of CPN and PMMA were evaluated in human cadaveric and decalcified sheep vertebral models and then compared to the results from solid rigid foam model (Sawbones#1522-23). The dispersion abilities of CPN and PMMA were evaluated via three methods as follows. The dispersion volume and dispersion ratio were calculated by three-dimensional reconstruction using human vertebral body CT scans; the ratio of cement area to injection volume was calculated from three-dimensional sections of micro-CT scans of a sheep vertebra; and the micro-CT images of cement dispersion in open-cell rigid foam model (Sawbones#1522-507) were compared between CPN and PMMA. This study was funded by the National Natural Science Foundation of China (No. 81622032, 190,000 dollars and No. 51672184, 90,600 dollars), Principal Project of Natural Science Research of Jiangsu Higher Education Institutions (No. 17KJA180011, 22,000 dollars), and Jiangsu Innovation and Entrepreneurship Program (146,000 dollars).

RESULTS

There was no significant difference in vertebral height between CPN and PMMA during PKP augmentation and both cements restored the vertebral height after augmentation. In PKP augmentation experiment, posterior wall cement leakage occurred in 75% of human vertebrae augmented with PMMA; however, no leakage occurred in human vertebrae augmented with CPN. Anterior leakage occurred in all vertebrae augmented by PMMA, while in only 75% of vertebra augmented by CPN. Furthermore, CPN and PMMA had completely different leakage patterns in the simulated rigid foam model whether administered at the same injection speed or under the same injection force, suggesting that CPN has anti-leakage characteristics. The augmentation in human cadaveric vertebrae was lower with CPN compared to PMMA (1,668±816 N vs. 2,212±813 N, p=.459, respectively), but this difference was not significant. The augmentation force in sheep vertebral bodies reached 1,393±433 N when augmented with PMMA, but 1,108±284 N when augmented with CPN. The dispersion of CPN was better, and the dispersion volume and ratio were greater, with CPN than with PMMA. Imaging of the open-cell rigid foam model showed completely different dispersion modes for CPN and PMMA. After injection, the PMMA cement formed a contracted clump in the open-cell rigid foam model. However, the CPN cement extended many antennae outward, appearing to spread to the surrounding area. The surface areas of the CPN cement blocks with different liquid-to-solid ratios were significantly larger than the surface area of the PMMA cement in the open-cell rigid foam model (p<.05).

CONCLUSIONS

CPN has anti-leakage properties, which might be related to its high viscosity and viscoplasticity. CPN had a slightly lower augmentation force than PMMA when used in cadaveric vertebrae, decalcified sheep vertebrae, and in the standard rigid foam model. However, CPN diffused more easily into cancellous bone than did PMMA and encapsulated bone tissue during the dispersion process. The excellent dispersion of CPN generated better interdigitation with cancellous bone, which may be why the augmentation effect of CPN is similar to that of PMMA.

CLINICAL SIGNIFICANCE

Biodegradable CPN is a potential alternative to PMMA cement in PKP surgery, in which CPN is likely to reduce the cement leakage during the surgery and avoid the post-surgery complications caused by excessive strengths and nondegradability of PMMA cement.

Safety of Cement Distribution Patterns in Metastatic Vertebral Tumors: A Retrospective Study

Background

Kyphoplasty (KP) is a palliative treatment for patients with metastatic vertebral tumors. The distribution pattern of cement affects safety and efficacy. The distribution pattern of cement has not been previously reported for patients with metastatic vertebral tumors.

Material/Methods

From January 2013 to December 2017, patients with metastatic vertebral tumors who met our criteria were divided into cement fusion (n=91) and separation (n=97) groups. Visual analogue scale (VAS) and middle vertebral height (MVH) were evaluated preoperatively, postoperatively, and 1 year after surgery. Spinal Instability Neoplastic Score, fluoroscopy time, operation time, cement volume, cement leakage, and vertebral fractures were recorded and evaluated.

Results

Compared with the fusion group, the separation group had significantly different (P<0.001) operation time, fluoroscopy time, and cement volume. Compared with preoperative status, VAS and MVH were significantly improved 3 days postoperatively and 1 year postoperatively in both groups (P<0.001). The difference in cement leakage between the 2 groups (P<0.05) and in the number of adjacent vertebral fractures between the 2 groups (P<0.05) were significant.

Conclusions

The distribution patterns of the bone cement had a good analgesic effect and preventive effect on vertebral collapse. However, the separation of bone cement may be safer.

Percutaneous kyphoplasty: Risk Factors for Recollapse of Cemented Vertebrae

INTRODUCTION

Percutaneous kyphoplasty can offer pain relief and restoration of vertebral height immediately after the procedure; however, little is known about how many vertebrae recollapse during follow-up or why recollapse occurs. In the present study, we define recollapse of a treated vertebra, assess how common it is following percutaneous kyphoplasty, and investigate risk factors for the condition.

METHODS

In total, 203 consecutive patients who underwent percutaneous kyphoplasty were reviewed after an average 12.7 months to assess what proportion of cement-augmented vertebrae had recollapsed. Potential risk factors for recollapse included age, gender, body weight, body height, body mass index, treated level, duration of symptoms, follow-up duration, preoperative T-scores, surgical approach, the intravertebral cleft, contact of polymethyl methacrylate (PMMA) with endplates, cement volume, cement leakage, and midline vertebral body height. Stepwise multivariate linear regression was conducted to predict recollapse as quantified by midline vertebral height loss.

RESULTS

Overall, 38.9% of the augmented vertebrae recollapsed. In the recollapse group, the average midline vertebral height ratio and kyphotic angles statistically significantly changed during follow-up (P < 0.05). Pain scores decreased immediately after percutaneous kyphoplasty and generally remained low at follow-up. Significant predictors of midline vertebral height loss at follow-up included presence of an intravertebral cleft, postoperative vertebral height, and non-PMMA-endplate-contact. Together, these factors accounted for 28% of the variability in midline height loss.

CONCLUSIONS

Benefits of percutaneous kyphoplasty are partly offset by subsequent recollapse. Recollapse is greater if there is an intravertebral cleft, non-PMMA-endplate-contact and an increase in the post vertebral height.

Distribution Pattern Making Sense: Patients Achieve Rapider Pain Relief with Confluent Rather Than Separated Bilateral Cement in Percutaneous Kyphoplasty for Osteoporotic Vertebral Compression Fractures

BACKGROUND

It has been reported the distribution of bone cement in percutaneous kyphoplasty (PKP) has an impact on the curative effect. No studies have compared between confluent and separated cement pattern of bilateral bone cement in PKP for patients with osteoporotic vertebral compression fractures.

METHODS

Between 2010 and 2016, 1341 patients were enrolled and divided into 2 groups. Group A (n = 723), bilateral cement was confluent; Group B (n = 618), bilateral cement was separated. The visual analogue scale (VAS), Oswestry Disability Index (ODI), anterior vertebral height (AVH), and local kyphotic angle (LKA) were obtained preoperatively, 2 days after surgery, and at the final follow-up to assess the functional and radiographic efficacy of the surgery.

RESULTS

The VAS, ODI, AVH, and LKA 2 days after operation and at the final follow-up were significantly improved compared with the preoperative for both groups (P < 0.05). There existed no significant difference between groups at various time point in ODI, AVH, and LKA (P > 0.05). Group A showed better VAS than group B 2 days after surgery (1.91 ± 0.98 vs. 2.35 ± 0.78, P < 0.001), also with better pre-postoperative VAS change (6.23 ± 0.76 vs. 5.75 ± 1.02, P < 0.001). Multiple linear regression for pain relief degree revealed group A (P < 0.001), older age (P < 0.001), and more cement volume (P < 0.001) contribute to rapid improvement of back pain. The cement leakage rate was 3.7% in group A and 2.9% in group B, with no significant difference (P = 0.405).

CONCLUSIONS

Patients achieved rapider pain relief with confluent rather than separated bilateral bone cement pattern in PKP for osteoporotic vertebral compression fracture.

Analyses of the efficacy of percutaneous kyphoplasty and alendronate sodium on thoracolumbar vertebral fracture and the risk factors of fracture

The present study investigated the efficacy of percutaneous kyphoplasty and alendronate sodium on thoracolumbar vertebral fracture, and the risk factors leading to the recurrence of fracture. In the present study, a total of 80 patients with thoracolumbar vertebral fracture who were admitted to the Affiliated Jiangyin Hospital of Southeast University Medical College between January 2014 and March 2016 for combination treatment of percutaneous kyphoplasty and alendronate sodium were enrolled. According to the recurrence of fracture, the patients were divided into two groups, the observation group (patients with fracture recurrence, n=40) and control group (patients with no fracture recurrence, n=40). All patients participated in a 1-year follow-up. The recurrence of fracture and the site of fracture were identified through the clinical symptoms and examination of the spine using magnetic resonance imaging. In addition, comparisons of the time of alleviation in numbness of lower limb and that in pains in waist and legs were carried out. Furthermore, statistics on the adverse reactions during intervention in the two groups were also collected; changes in visual analogue scale (VAS) and Oswestry Disability Index (ODI) of pains at different time points in two groups were also observed. One-way analysis and multivariate analysis were performed to identify the relevant risk factors. Alleviation time in numbness of lower legs in patients of the control group was significantly earlier than that in the observation group (P<0.05) and the alleviation time in pains of the waist and legs of patients in the control group was also significantly earlier than that in the observation group (P<0.05). Furthermore, the incidence rates of abdominal pain, diarrhea, constipation and hypocalcemiain in the control group were also significantly lower compared with those in the observation group (P<0.05). One week, one month and one year after operation, the scores of VAS of pains and ODI in the control group were significantly lower compared with those in the observation group in the same period (P<0.05). Lower preoperative bone density and exosmosis of bone cement in treatment were the independent risk factors leading to the recurrence of fracture. For patients with thoracolumbar vertebral fracture who received the combination treatment of percutaneous kyphoplasty and alendronate sodium, there underlies an important correlation between the recurrence rate of fracture and the preoperative bone density as well as the exosmosis of bone cement in operation.

The risk factors of vertebral refracture after kyphoplasty in patients with osteoporotic vertebral compression fractures: a study protocol for a prospective cohort study

BACKGROUND

Percutaneous kyphoplasty (PKP) is the first-line treatment for osteoporotic vertebral compression fractures (OVCFs) that can immediately relieve pain and allow the quick recovery of lost mobility. However, some studies reported that after PKP, the incidence of vertebral refracture, particularly adjacent vertebral fracture (AVF), was high. Our previous meta-analysis suggested that the risks for vertebral refracture and AVF did not increase after percutaneous vertebral augmentation in OVCF patients. Despite the negative results of our meta-analysis, there is still significant evidence regarding the relationship between kyphoplasty and AVF, so a new prospective cohort study is warranted. In addition, in our previous retrospective study, we found that advanced age, female sex and low oestradiol (E₂) concentrations might be related to the occurrence of postoperative vertebral refracture after PKP. To sufficiently evaluate the probable factors involved in the occurrence of postoperative vertebral refracture, we designed this prospective study.

METHODS

This is a prospective cohort study of patients admitted for PKP to treat painful OVCFs. The baseline data, including demographic information, lifestyle, bone metabolic status, sex hormone and sex hormone-binding globulin (SHBG) levels, and clinical characteristics will be collected at the time of enrolment. Surgical features of PKP will be recorded on the operation day. Lifestyle, bone metabolic status, sex hormone levels, and SHBG levels will be assessed during the follow-up period at 1 m, 3 m, 12 m, and 24 m postoperatively. Patients suffering from acutely aggravated back pain will be referred to an orthopaedist, and refractured vertebrae will be confirmed by magnetic resonance imaging and computed tomography. The primary outcome will be the incidence of vertebral refracture. Multivariate analyses will be carried out to evaluate the variables that are independently correlated with vertebral refracture.

DISCUSSION

To evaluate the risk of postoperative refracture preoperatively and to identify the surgical points related to postoperative refracture, this study will explore the risk factors related to vertebral refracture after PKP. The results may provide new information about defining OVCF patients suitable for PKP treatment.

TRIAL REGISTRATION

ChiCTR-ROC-17011562 . Registered on July 4th, 2017.

Bone cement distribution is a potential predictor to the reconstructive effects of unilateral percutaneous kyphoplasty in OVCFs: a retrospective study

Background

Osteoporotic vertebral compression fracture (OVCF) is a common type of fracture, and percutaneous kyphoplasty (PKP) is an eligible solution to it. Previous studies have revealed that both the volume and filling pattern of bone cement correlate with the clinical outcomes after PKP procedure. However, the role of bone cement distribution remains to be illustrated.

Methods

To retrospectively evaluate the relationship between the bone cement distribution and the clinical outcomes of unilateral PKP, we enrolled 73 OVCF patients receiving unilateral PKP treatment. All the intervened vertebrae were classified into three groups based on the bone cement distribution observed on postoperative X-ray films. Preoperative and postoperative radiographic parameters including the vertebral height and kyphotic Cobb angle were recorded, and anterior vertebral height restoration rate (AVHRR) and Cobb angle correction (CR) were then calculated to assess the vertebral height reconstruction. Preoperative and postoperative Oswestry Disability Index (ODI) and visual analogue scale (VAS) were adopted by interviewing patients to assess the mobility improvement and pain relief. Demographic data, body mass index (BMI), lumbar bone mineral density (evaluated by BMD T-score) of each patient, bone cement volume (BV), and bone cement extravasation (BE) were also recorded. Between- and within-group comparisons and multivariable correlation analysis were carried out to analyze the data.

Results

VAS and ODI scores were both significantly improved in all of the enrolled cases with no significant differences between groups. Among the three groups, the average age, AVHRR, and BV were significantly different. Occurrence of BE was significantly different between two of the three groups. AVHRR was demonstrated to correlate negatively with preoperative anterior vertebral height ratio and positively with preoperative Cobb angle, CR, diffusion score, and ODI changes.

Conclusions

Bone cement distribution is a potential predictor to the reconstructive effects in unilateral PKP for OVCFs. Bone cement distribution is associated with AVHRR and BV, as well as the risk of BE occurrence. Greater bone cement distribution may indicate better vertebral restoration along with a higher BE risk.