Optimal intravertebral cement volume in percutaneous vertebroplasty for painful osteoporotic vertebral compression fractures

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.

Effect of cement volume on biomechanical response of a spine segment treated with a PEEK polymer implant: a finite element comparative study with vertebroplasty

In the current study, a 3D finite element study was performed to investigate the biomechanical response of an osteoporotic spine segment treated with a novel transpedicular implant (V-STRUT©, Hyprevention, France) made of PEEK (polyetheretherketone) material combined with either injections of 2, 3, 4, 5 and 6 cc of cement. The objective was to assess numerically the biomechanical performance of the implant in combination with different doses of the injected bone cement and to compare its performance with the gold standard vertebroplasty (VP) technique. A female (69 yo) was selected and a 3D finite element model of an osteoporotic spine segment was built based on a Computed Tomography (CT) scan performed from T12 to L2 with corresponding intervertebral discs and ligaments. A heterogeneous distribution of bone material properties was assigned to the bone using grey scale levels. Bilateral ellipsoid geometries of the inserted cement were retained for the V-STRUT and VP models based on experimental observation performed on different patients treated with the V-STRUT device. The current study demonstrated an optimal dose of 4 cc of bilaterally injected cement for the V-STRUT and VP techniques to restore the treated segment and confirmed that the V-STRUT device in combination with bone cement is superior to VP alone in establishing the normal stiffness and in reducing the applied stress to the immediately adjacent vertebral levels.

Percutaneous kyphoplasty with or without posterior pedicle screw fixation for the management of severe osteoporotic vertebral compression fractures with nonunion

OBJECTIVE

To assess the radiographic outcomes, clinical outcomes and complications of percutaneous kyphoplasty (PKP) with and without posterior pedicle screw fixation (PPSF) in the treatment of severe osteoporotic vertebral compression fractures (sOVCF) with nonunion.

METHODS

This study involved 51 patients with sOVCF with nonunion who underwent PKP or PPSF + KP. The operation time, intraoperative blood loss, volume of injected bone cement, operation costs and hospital stays were all recorded. In addition, the Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) were assessed separately for each patient before and after surgery.

RESULTS

Compared with the PPSF + KP group, the PKP group had shorter operation time, less intraoperative blood loss, shorter hospital stays and fewer operation costs. However, cobb's angle improvement (13.4 ± 4.3° vs. 21.4 ± 5.3°), VWR improvement ratio (30.4 ± 11.5% vs. 52.8 ± 12.7%), HA (34.9 ± 9.0% vs. 63.7 ± 7.6%) and HM (28.4 ± 11.2% vs. 49.6 ± 7.7%) improvement ratio were all higher in PPSF + KP group than that in PKP group. In addition, the ODI index and VAS score in both groups were significantly decreased at the postoperative and final follow-up. PKP group's postoperative VAS score was significantly lower than that in PPSF + KP group, but there was no statistically significant difference in VAS score at the last follow-up.

CONCLUSION

PKP and PPSF + KP can both effectively relieve the pain associated with sOVCF with nonunion. PPSF + KP can achieve more satisfactory vertebral reduction effects compared to PKP. However, PKP was less invasive and it has more advantages in shortening operation time and hospital stay, as well as decreasing intraoperative blood loss and operation costs.

Percutaneous Curved Vertebroplasty Decrease the Risk of Cemented Vertebra Refracture Compared with Bilateral Percutaneous Kyphoplasty in the Treatment of Osteoporotic Vertebral Compression Fractures

Purpose

The purpose of this study is to compare the refracture rate of the cemented vertebral body of percutaneous curved vertebroplasty (PCVP) and bilateral percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fractures (OVCF).

Methods

Ninety-four patients with single segment thoracolumbar OVCF were randomly divided into two groups (47 patients in each) and underwent PCVP or bilateral PKP surgery, respectively. Refracture of cemented vertebral body, bone cement injection volume and cement pattern, cement leakage rate, total surgical time, intraoperative fluoroscopy time, preoperative and postoperative Cobb angles and anterior vertebral height, Oswestry disability index questionnaire (ODI) and visual analog scales (VAS) were recorded.

Results

The PCVP group had significantly lower refracture incidence of the cemented vertebral than the bilateral PKP group (p<0.05). There was a significant postoperative improvement in the VAS score and ODI in both group (p<0.01), and no significant difference was found between two groups. The operation time and intraoperative fluoroscopy times were significantly less in the PCVP group than in the bilateral PKP group (p<0.01). The mean kyphosis angle correction and vertebral height restoration in the PCVP group was significantly less than that in the bilateral PKP group (p<0.01).

Conclusion

Both PCVP and PKP were safe and effective treatments for OVCF. The PCVP had lower refracture rate of the cemented vertebral than the bilateral PKP group, and PCVP entailed less exposure to fluoroscopy and shorter operation time than bilateral PKP.

Percutaneous Curved Vertebroplasty Versus Unilateral Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

Percutaneous curved vertebroplasty (PCVP), a modified traditional unilateral percutaneous vertebroplasty (UPVP) technique, is increasingly being used to treat osteoporotic vertebral compression fractures (OVCFs); however, its advantages remain controversial. This meta-analysis was conducted to determine whether PCVP is superior to traditional UPVP in treating OVCFs.

METHODS

Six databases were searched for studies comparing the clinical efficacy of PCVP and UPVP in treating patients with OVCFs published until March 2023. After study selection, data extraction, and risk of bias evaluation, a meta-analysis was conducted. The study protocol was registered in the PROSPERO platform (registration number: CRD42023417190).

RESULTS

Eight studies (6 randomized controlled trials and 2 cohort studies) were eligible for the final analysis. The pooled results revealed no between-group differences in operation time (P = 0.85), intraoperative fluoroscopy (P = 0.58), or postoperative short-term visual analog scale scores (P = 0.15). However, PCVP was associated with more injected cement (P = 0.003), a lower cement leakage rate (P = 0.006), and a lower final follow-up visual analog scale score (P < 0.0001).

CONCLUSIONS

PCVP was superior to UPVP in terms of reducing the bone cement leakage rate and providing long-term pain relief. Further trials with larger sample sizes and longer follow-up periods are required to verify these findings owing to the potential risk of bias.

Evaluation of multidetector CT Hounsfield unit measurements as a predictor of efficacy and complications in percutaneous vertebroplasty for osteoporotic vertebral compression fractures

Introduction

More than 30 years after the initial experience of Galibert and Deramond with percutaneous vertebroplasty, the procedure has gone through countless refinements and clinical evaluations. Predictors for the success and failure of the procedure in the literature vary and are focused on the duration of complaints, type of fracture, presence of edema on MRI scans, etc. We propose using a quantitative method based on a standard CT examination of the thoracic or lumbar spine to assess the risks and potential success of performing vertebroplasty.

Materials and methods

This is a single-center prospective observational study on 139 patients treated with percutaneous vertebroplasty (pVPL) for a single symptomatic osteoporotic vertebral compression fracture (OVCF). We measured the levels of disability and pain preoperatively and again at the 3-, 6- and 12-month marks using the standardized VAS and ODI questionnaires. Every patient in the study was evaluated with postoperative multidetector CT (MDCT) to determine the presence, extent, and localization of vertebral cement leakage and to measure the adjacent vertebrae's minimal and mean density in Hounsfield units (HUmin and HUmean, respectively).

Results

We determined that a slight (r = -0.201) but statistically significant (p = 0.018) correlation existed between HU measurements taken from radiologically intact adjacent vertebrae and the procedure's effect concerning the pain levels at the 3-month follow-up. This correlation failed to reach statistical significance at 12 months (p = 0.072). We found no statistically significant relationship between low vertebral cancellous bone density and cement leakage on postoperative scans (p = 0.6 for HUmin and p = 0.74 for HUmean).

Conclusion

We have moderately strong data that show a negative correlation between the mean values of vertebral cancellous bone density in patients with OVCF and the effect of pVPL in reducing pain. Lower bone densities, measured this way, showed no increased risk of cement leakage.

Interpretable Machine Learning Model to Predict Bone Cement Leakage in Percutaneous Vertebral Augmentation for Osteoporotic Vertebral Compression Fracture Based on SHapley Additive exPlanations

STUDY DESIGN

Retrospective study.

OBJECTIVES

Our objective is to create comprehensible machine learning (ML) models that can forecast bone cement leakage in percutaneous vertebral augmentation (PVA) for individuals with osteoporotic vertebral compression fracture (OVCF) while also identifying the associated risk factors.

METHODS

We incorporated data from patients (n = 425) which underwent PVA. To predict cement leakage, we devised six models based on a variety of parameters. Evaluate and juxtapose the predictive performances relied on measures of discrimination, calibration, and clinical utility. SHapley Additive exPlanations (SHAP) methodology was used to interpret model and evaluate the risk factors associated with cement leakage.

RESULTS

The occurrence rate of cement leakage was established at 50.4%. A binary logistic regression analysis identified cortical disruption (OR 6.880, 95% CI 4.209-11.246), the basivertebral foramen sign (OR 2.142, 95% CI 1.303-3.521), the fracture type (OR 1.683, 95% CI 1.083-2.617), and the volume of bone cement (OR 1.198, 95% CI 1.070-1.341) as independent predictors of cement leakage. The XGBoost model outperformed all others in predicting cement leakage in the testing set, with AUC of .8819, accuracy of .8025, recall score of .7872, F1 score of .8315, and a precision score of .881. Several important factors related to cement leakage were drawn based on the analysis of SHAP values and their clinical significance.

CONCLUSION

The ML based predictive model demonstrated significant accuracy in forecasting bone cement leakage for patients with OVCF undergoing PVA. When combined with SHAP, ML facilitated a personalized prediction and offered a visual interpretation of feature importance.

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.

The significance of the best puncture side bone cement/vertebral volume ratio to prevent paravertebral vein leakage of bone cement during vertebroplasty: a retrospective study

OBJECTIVES

To verify the clinical significance of the best puncture-side bone cement/vertebral volume ratio (PSBCV/VV%) and bone cement leakage in paravertebral veins during vertebroplasty.

METHODS

This was a retrospective analysis of a total of 210 patients from September 2021 to December 2022, who were divided into an observation group (110 patients) and a control group (100 patients). In the observation group, patients' preoperative computed tomography (CT) data were imported into Mimics software, and the VV was calculated using the three-dimensional (3D) reconstruction function. Then, based on the best PSBCV/VV% of 13.68% determined in a previous study, the optimal PSBCV to be injected during vertebroplasty was calculated. In the control group, vertebroplasty was performed directly using the conventional method. The incidence of cement leakage into paravertebral veins was observed postoperatively in both groups.

RESULTS

There were no statistically significant differences (P > 0.05) in the evaluated indicators between the two groups pre- or postoperatively, including the anterior vertebral margin height, mid-vertebral height, injured vertebral Cobb angle, visual analogue scale (VAS) score, and Oswestry Disability Index (ODI). Intragroup comparisons showed improvements in the anterior vertebral height, mid-vertebral height, injured vertebral Cobb angle, VAS score, and ODI after surgery compared with before surgery (P < 0.05). In the observation group, there were 3 cases of cement leakage into the paravertebral veins, for a leakage rate of 2.7%. In the control group, there were 11 cases of cement leakage into the paravertebral veins, for a leakage rate of 11%. The difference in the leakage rate between the two groups was statistically significant (P = 0.016).

CONCLUSION

In vertebroplasty, preoperative VV calculations using Mimics software, combined with calculation of the PSBCV according to the best PSBCV/VV% (13.68%), can effectively prevent leakage of bone cement into paravertebral veins and further prevent serious life-threatening complications such as pulmonary embolism.

Balloon kyphoplasty versus percutaneous vertebroplasty for osteoporotic vertebral body compression fractures: clinical and radiological outcomes

BACKGROUND CONTEXT

Osteoporotic vertebral body compression fracture are the commonest fractures amongst the other osteoporotic fracture sites. These fragility fractures are the result of low energy mechanical forces that that would not ordinarily result in fracture. Percutaneous vertebroplasty and balloon kyphoplasty has been widely used as minimally invasive procedures to treat painful vertebral compression fractures.

PURPOSE

Aim of the present study was to evaluate radiological, clinical and functional outcome of patients with osteoporotic vertebral body fractures treated with Balloon Kyphoplasty and Vertebroplasty.

STUDY DESIGN

Prospective cohort study PATIENT SAMPLE: 40 patients (Male:15, Female: 25) with average age of 56 +/- 8 years diagnosed with osteoporotic vertebral body compression fracture on clinical and radiological evaluation with no neurological deficit and no other associated fractures were included.

OUTCOME MEASURES

Operative time, cost for the procedure, gain in vertebral body height, reduction in pain, ability to perform daily routine activities, risk of cement leakage and any other systemic complications were evaluated and compared in both the study groups.

METHODS

All the patients underwent conventional Xray, MRI (to rule out acute from chronic fracture, to check compromise of spinal canal and calculate collapse in vertebral body height), Visual analog scaling for severity of pain and difficulty in daily routine activities by Oswestry disability index preoperatively. Post operative clinal, functional, radiological outcome and complications were compared in patients treated with percutaneous vertebroplasty and balloon kyphoplasty.

RESULT

There was significant difference in intraoperative time period and procedure cost for the patients treated with Vertebroplasty(50.75min, 25k) in comparison to balloon kyphoplasty (71.95, 50k) with p value being < .001 There was significant difference between preoperative and postoperative study parameters in both the study groups but there was no significant difference in post operative study parameters amongst both the study groups with p values >.05 for different parameters, 0.381(Gain in vertebral height), 0.108 (pain relief), 0.846(Oswestry disability index) and 0.197(risk of cement leakage) CONCLUSION: Our study suggested that percutaneous vertebroplasty requires less operative time and is more economical than balloon kyphoplasty. Increase in intraoperative time increases the risk of infection. Though the cases of Intraoperative operative cement leakage were more in percutaneous vertebroplasty but is was not significant. However the final radiological, clinical, functional outcome and overall complications were found to be similar in both the groups. Balloon kyphoplasty provided no added benefit over percutaneous vertebroplasty. A study with larger sample size will be needed to warrant one surgical procedure superior to other in the treatment of osteoporotic vertebral body compression fracture.

Analysis of optimal volume fraction percentage and influencing factors of bone cement distribution in vertebroplasty using digital techniques

Purpose

To explore the optimal volume fraction percentage (VF%) and influencing factors of bone cement distribution in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCF) using digital techniques.

Patients and methods

From January 2019 to February 2021, 150 patients with 0VCF who underwent PVP surgery in our hospital were analyzed. Based on postoperative X-ray and CT, the spatial distribution score of the intravertebral cement was calculated and the patients were divided into two groups: 0–7 were divided into group A; 8–10 were divided into group B. The general data of the two groups of patients were compared, and Mimics three-dimensional reconstruction images were used to measure the cement dispersion volume (CDV), vertebral body volume (VBV), and VF%. Factors affecting bone cement distribution were included in a multifactorial logistic regression analysis to construct a receiver operating characteristic (ROC) curve, calculate a cut-off value for the extensive distribution of bone cement, and analyze the correlation between bone cement distribution scores and VF%.

Results

There were 60 patients in group A and 90 patients in group B. Univariate analysis showed that bone mineral density (BMD), cement leakage, CDV, and VF% were significantly lower in group A than in group B (p < 0.05). Multivariate logistic regression analysis showed that BMD and VF% were independent influencing factors on bone cement distribution. The area under the curve (AUC) of VF% was 84.7%, and the cut-off value for extensive distribution of bone cement was 28.58%, which corresponded to a sensitivity and specificity of 72.2% and 91.7%, respectively. There was a strong correlation between the cement distribution score and VF% (r = 0.895, p < 0.001).

Conclusion

BMD and VF% were important independent influencing factors of bone cement distribution. Extensive bone cement distribution can be achieved when the VF% reaches 28.58%.

Analysis of the Curative Effect of Curved Angle Vertebroplasty in the Treatment of Osteoporotic Vertebral Compression Fracture

Objective

To evaluate the clinical efficacy of Percutaneous curved vertebroplasty (PCVP) for osteoporotic vertebral compression fracture of the thoracolumbar spine.

Methods

Retrospective analysis of 113 patients with osteoporotic vertebral compressive fractures (OVCFs) in our hospital from January 2017 to January 2020, a total of 120 diseased vertebrae, were divided into PCVP group (35 cases, 37 sections) and bilateral PVP(BVP) group (78 cases, 83 sections). To compare the distribution of baseline clinical data, pain relief (Visual Analog Scale, VAS), ODI (Oswestry Dability Index, ODI), operation time, intraoperative fluoroscopy, postoperative vertebral body re-fracture, and comparison of bone, and to compare the volume of cement penetration and the leakage rate of bone cement, etc.

Results

There was no significant difference in VAS and ODI before operation between the two groups (P > 0.05), and the VAS score and ODI after operation were significantly improved (P < 0.001). Compared with the bilateral PVP group, the operation time, the number of fluoroscopy, and the leakage rate of each layer of bone cement in the PCVP group were significantly reduced (P < 0.05); however, the amount of cement used in the two groups was similar (P > 0.05). There were no serious complications in both groups. In the bilateral PVP group, a total of seven patients had adjacent vertebral fractures or re-fractures of the original vertebral body. However, no patients in the PCVP group had re-fractures in any vertebral body segment.

Conclusion

Both PCVP and bilateral PVP are safe and effective methods for the treatment of osteoporotic vertebral compression fractures, but PCVP has a short operation time, fewer fluoroscopy times, and a low bone cement leakage rate.

Computer-assisted simulated workplace-based assessment in surgery: application of the universal framework of intraoperative performance within a mixed-reality simulation

Objectives

Workplace-based assessment (WBA) is a key requirement of competency-based medical education in postgraduate surgical education. Although simulated workplace-based assessment (SWBA) has been proposed to complement WBA, it is insufficiently adopted in surgical education. In particular, approaches to criterion-referenced and automated assessment of intraoperative surgical competency in contextualized SWBA settings are missing.Main objectives were (1) application of the universal framework of intraoperative performance and exemplary adaptation to spine surgery (vertebroplasty); (2) development of computer-assisted assessment based on criterion-referenced metrics; and (3) implementation in contextualized, team-based operating room (OR) simulation, and evaluation of validity.

Design

Multistage development and assessment study: (1) expert-based definition of performance indicators based on framework's performance domains; (2) development of respective assessment metrics based on preoperative planning and intraoperative performance data; (3) implementation in mixed-reality OR simulation and assessment of surgeons operating in a confederate team. Statistical analyses included internal consistency and interdomain associations, correlations with experience, and technical and non-technical performances.

Setting

Surgical simulation center. Full surgical team set-up within mixed-reality OR simulation.

Participants

Eleven surgeons were recruited from two teaching hospitals. Eligibility criteria included surgical specialists in orthopedic, trauma, or neurosurgery with prior VP or kyphoplasty experience.

Main outcome measures

Computer-assisted assessment of surgeons' intraoperative performance.

Results

Performance scores were associated with surgeons' experience, observational assessment (Objective Structured Assessment of Technical Skill) scores and overall pass/fail ratings. Results provide strong evidence for validity of our computer-assisted SWBA approach. Diverse indicators of surgeons' technical and non-technical performances could be quantified and captured.

Conclusions

This study is the first to investigate computer-assisted assessment based on a competency framework in authentic, contextualized team-based OR simulation. Our approach discriminates surgical competency across the domains of intraoperative performance. It advances previous automated assessment based on the use of current surgical simulators in decontextualized settings. Our findings inform future use of computer-assisted multidomain competency assessments of surgeons using SWBA approaches.

Continuous cement leakage along the posterior longitudinal ligament of the intraspinal epidural during a percutaneous vesselplasty: A case report and literature review

Objective

This study aims to report one case of intraspinal epidural cement leakage caused by a novel percutaneous vesselplasty.

Methods

A clinical case report from the Orthopedic center of our hospital and a literature review. A 63-year-old woman with an L₂ osteoporotic compression fracture underwent novel kyphoplasty, percutaneous vesselplasty. This rare complication was evaluated through a literature search, and its special types are classified in more detail.

Results

The patient was hospitalized with low back pain two weeks after a fall. After auxiliary examination, a new type of percutaneous vesselplasty was performed. After the intraoperative injection of bone cement, bone cement leakage extended along the posterior longitudinal ligament and epidural space. There were no special compression symptoms of the spinal cord, and the prognosis of conservative treatment was good.

Conclusion

Although percutaneous vesselplasty is relatively safe and frequent, intraspinal leakage may occur, so sufficient preoperative evaluation, intraoperative continuous fluoroscopic monitoring, and timely evaluation of postoperative images are extremely necessary.

A novel classification of cement distribution patterns based on plain radiographs associated with cement filling rate and relevance to the clinical results of unipedicle vertebroplasty

INTRODUCTION

Cement distribution pattern following unipedicle percutaneous vertebroplasty (UVP) for osteoporotic vertebral compression fractures (OVCFs) has been reported in association with clinical results. The present retrospective study aimed to classify the bone cement distribution types following UVP and investigate the differences in clinical efficacy and related complications.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of the patients with single-segment OVCFs who underwent UVP. Cement distribution patterns were divided into the diffuse, block, double band, and single band types according to the plain radiographs and further by cement filling rate (CFR) based on a three-dimension reconstruction of post-operative CT. The cutoff values of CFR were > 34% for the diffuse, block between 34 and 20%, and each band of the double or single band < 20%. Clinical efficacy and related complications were compared among the four cement distribution types 24 h after the operation and the last follow-up.

RESULTS

A total of 155 patients with an average follow-up time of 20.3 months were included. The diffuse type included 26 patients; block, 87; double band, 18; and single band, 24. The VAS and ODI after operation improved significantly in all four groups. The diffuse and block types had similar clinical results. The clinical outcomes in the single band group were the poorest at the last follow-up. The patients with single band type also had the highest rates of body re-collapse and revision surgery for the index level.

CONCLUSION

Diffuse and block groups can better maintain the height of the vertebral body and reduce the risk of vertebral body recompression. The single band has the poorest results, and intraoperative immediate contralateral vertebroplasty was highly recommended.

Radiographic adjacent segment degeneration and risk factors for osteoporotic vertebral compression fractures treated with percutaneous kyphoplasty

PURPOSE

In this study, we aimed to clarify whether osteoporotic vertebral compression fracture (OVCF) following percutaneous kyphoplasty (PKP) was associated with a high risk for radiographic adjacent segment degeneration (ASD) and to identify the risk factors for radiographic ASD in these individuals.

METHODS

We retrospectively reviewed consecutive patients with OVCFs who underwent PKP at our institution between November 2015 and January 2021. The incidence of radiographic ASD was calculated and specific subgroups of ASD were identified. Univariate and multivariate analyses of demographic, clinical baseline, and radiologic data were performed to identify risk factors associated with radiographic ASD.

RESULTS

With a mean follow-up time of 27.3 months, a total of 95 eligible patients were enrolled. The incidence of radiographic ASD distinguished from natural degeneration was 52.6%. Patients with OVCFs who underwent PKP had a high risk of developing radiographic ASD, particularly disc degeneration. Intradiscal cement leakage (odds ratio [OR], 5.706; 95% confidence interval [CI], 2.039-15.970; P = 0.001) and preoperative disc height (OR, 0.681; 95% CI, 0.518-0.895; P = 0.006) were identified as independent risk factors.

CONCLUSION

Patients with OVCFs who underwent PKP were more likely to develop radiographic ASD, and their progression was distinguished from natural degeneration. Disc degeneration was the most common type of degeneration. Intradiscal cement leakage and preoperative disc height were identified as independent risk factors for developing radiographic ASD in these patients. Further validation through prospective multicenter studies is required.

A novel scoring system to predict the residual back pain after percutaneous kyphoplasty for osteoporotic vertebral compression fracture

Objective

To establish a scoring system to predict the residual back pain after percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture (OVCF).

Materials and methods

We retrospectively reviewed the clinical records of 98 patients who were diagnosed of single-vertebral OVCF and underwent PKP surgery in our department from January 2015 to December 2017. The following clinical characteristics including age, gender, disease course, fracture location, fracture type, segmental kyphosis, and bone cement volume were all recorded, and the effects of these factors on postoperative pain (at 1-month and 6-month postoperative) were also analyzed respectively. Based on 6-month postoperative VAS score, the included patients were divided into two groups, namely the residual back pain group (19 patients) and the non-residual back pain group (79 patients). The independent risk factors of residual back pain after PKP were screened and the scoring system was established by the multivariate logistic regression analysis. The performance of this scoring system was also prospectively validated using the clinical data of 45 patients with single-vertebral OVCF from January 2018 to December 2019.

Results

The scoring system was consist of five clinical characteristics which were confirmed as significant predictors of residual back pain after PKP, namely, age ≥60 years (P = 0.021), fracture location = thoracic or lumbar (P = 0.002), fracture type = OF4 type (P = 0.018), segmental kyphosis ≥20° (P = 0.014), and bone cement volume <5 ml (P = 0.001). Patients in the residual back pain group showed a significant higher score than the non-residual back pain group (6.84 ± 1.71 vs. 2.66 ± 1.97, t = 8.499, P < 0.001), and the optimal cut-off value for the scoring system was 5 points. The sensitivity and specificity of the scoring system for predicting residual back pain after PKP were 84.21% and 87.34%, respectively, in derivation set and 78.57% and 83.87% in validation set.

Conclusion

This novel scoring system showed satisfactory diagnostic efficacy in predicting residual back pain after PKP for single-vertebral OVCF. Patients with the score of 5–9 had a high risk of postoperative residual back pain, while the patients with score of 0–4 was low.

A predictive nomogram for intradiscal cement leakage in percutaneous kyphoplasty for osteoporotic vertebral compression fractures combined with intravertebral cleft

BACKGROUND

For patients with osteoporotic vertebral compression fractures (OVCFs) treated with percutaneous kyphoplasty (PKP), the occurrence and risk factors of intradiscal cement leakage should be characteristic of the presence of intravertebral cleft (IVC). This study aimed to identify risk factors for intradiscal leakage in individuals with OVCFs combined with IVC treated with PKP and build a powered and well-calibrated predictive nomogram.

METHODS

This study retrospectively reviewed consecutive patients who underwent PKP at our center between January 2016 and May 2021. Patients diagnosed with OVCFs combined with IVC were identified, and the incidence of different types of bone cement leakage was recorded. Risk factors for intradiscal leakage among the demographic, perioperative baseline, and radiologic data were identified, following which a nomogram was developed and verified.

RESULTS

A total of 109 eligible patients were included, and the intradiscal leakage rate was 32.1%. Compression rate (odds ratio [OR] 0.025; 95% confidence interval [CI] 0.002-0.264; P = 0.002) and cemented vertebral body fraction (OR 44.122; 95% CI 2.790-697.740; P = 0.007) were identified as independent risk factors. A predictive nomogram with good predictive power (C-statistic = 0.786) and fitness of data (Hosmer-Lemeshow goodness-of-fit test, P = 0.092) was established to build a quantitative relationship between the risk factors and intradiscal leakage.

CONCLUSION

The incidence rate of intradiscal leakage in PKP for OVCFs combined with IVC was 32.1%. Compression rate and cemented vertebral body fraction were identified as independent risk factors. A powered and well-calibrated nomogram was established to accurately predict the probability of intradiscal leakage. Further prospective and multicenter studies are required to verify and calibrate our findings.

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

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

A finite element analysis on different bone cement forms and injection volumes injected into lumbar vertebral body in percutaneous kyphoplasty

Background

To investigate the stress changes between different bone cement forms and injection volumes in adjacent vertebrae after percutaneous kyphoplasty (PKP) by establishing a three-dimensional finite element model of osteoporosis.

Methods

A male healthy volunteer was selected. CT of scans L1 to L3 vertebrae were imported into Mimics 21.0 software.The vertebral model of osteoporosiswas established based on previous literature reference. The models were divided into three groups: unilateral, bilateral integration and bilateral separation groups, with each group injecting 2 ml, 4,ml and 6 ml of bone cement, respectively. In all models, a vertical compressive load of 500 N, anterior flexion/posterior extension, left/right bending, and left/right rotation were applied with a moment of 7.5 N/m, of which 85% was applied to the anterior mid-column and 15% to the posterior column. The stress changes between adjacent vertebrae under different conditions were calculated.

Results

After percutaneous kyphoplasty was applied to the L2 vertebral body, some differences can be found between the effects of different cement injection volumes and cement morphology on adjacent structures. There was no major difference between the groups when the bone cement injection volume was 2 ml. When the amount of bone cement injected was 4 ml, the bone cement morphology of the bilateral integration group (BIG) produced less stress between adjacent vertebral bodies. The minimum stress was 14.95 MPa in the L3 vertebral body in posterior extension. Whereas the stress levels on adjacent intervertebral structures, BIG shaped bone cement shows some superiority. In addition, the adjacent vertebrae and intervertebral structures are subjected to less stress during left and right rotation.

Conclusions

The present finite element study suggested that bilateral integration bone cement is a suitable form of cement injection, and when the injection volume is 4 ml, reduces stress on adjacent segments by approximately 15% while maintaining the stability of the injected vertebral body.

Cement leakage in percutaneous vertebroplasty for spinal metastases: a retrospective study of risk factors and clinical outcomes

Objective

The objective of this research was to investigate the risk factors of cement leakage in patients with metastatic spine tumors following percutaneous vertebroplasty (PVP).

Methods

Sixty-four patients with 113 vertebrae were retrospectively reviewed. Various clinical indexes, including age, sex, body mass index (BMI), smoking history, drinking history, chemotherapy history, radiotherapy history, primary cancer, location, other metastases, collapse, posterior wall defects, the laterality of injection, and the injected cement volume were analyzed as potential risk factors. Multivariate analyses were conducted to identify the independent risk factors.

Results

The cement leakage was found 64 in 113 treated vertebrae (56.63%), in which the incidence of each type was shown as below: spinal canal leakage 18 (15.93%), intravascular leakage around the vertebrae 11 (9.73%), and intradiscal and paravertebral leakage 35 (30.97%). Tomita classification (P = 0.019) and posterior wall destruction (P = 0.001) were considered strong risk factors for predicting cement leakage in general. The multivariate logistic analysis showed that defects of the posterior wall (P = 0.001) and injected volume (P = 0.038) were independently related to the presence of spinal canal leakage. The postoperative visual analog scale (VAS) and activities of daily living (ADL) scores showed significant differences compared with the pre-operative parameters (P < 0.05). No significant differences were found in every follow-up time between the leakage group and the non-leakage group for pain management and improvement of activities in daily life.

Conclusion

In our study, Tomita classification and the destruction of the posterior wall were independent risk factors for leakage in general. The defects of the posterior wall and injected volume were independently related to the presence of spinal canal leakage. The PVP procedure can be an effective way to manage the pain.

Correlation analysis of the puncture-side bone cement/vertebral body volume ratio and bone cement leakage in the paravertebral vein in vertebroplasty

Objectives

To explore the influencing factors of bone cement leakage in the paravertebral vein after vertebroplasty for the treatment of osteoporotic vertebral compression fractures (OVCFs) and to determine the correlation between the puncture-side bone cement/vertebral body volume ratio and bone cement leakage in the paravertebral vein.

Methods

This was a retrospective analysis of 495 patients (585 vertebral bodies) with OVCFs treated from August 2018 to May 2021 in our hospital. The patients’ postoperative CT data were imported into Mimics software, and the three-dimensional(3D) reconstruction function was used to calculate the bone cement volume (BCV), puncture-side bone cement volume (PSBCV), and vertebral body volume (VBV); the bone cement/vertebral body volume ratio (BCV/VCV%) and puncture-side bone cement/vertebral body volume ratio (PSBCV/VCV%) were additionally calculated. Sex, Age, Body mass index(BMI), Bone density, BCV, PSBCV, VBV, BCV/VCV%, and PSBCV/VCV were compared between the leakage group and the non-leakage group. Logistic regression analysis was used to assess the correlations between the factors that statistically significantly differed between the two groups and the presence of leakage in the paravertebral veins. A receiver operating characteristic (ROC) curve was used to determine the diagnostic value of the PSBCV/VCV% and to obtain the optional cut-off value.

Results

A total of 102 males and 393 females with an average age of 72.89 (52 ~ 93) years were included in our study. There were 57 cases of cement leakage (59 vertebral bodies) in the paravertebral vein. There were 438 patients (526 vertebral bodies) without paravertebral cement leakage. Univariate analysis showed that the differences in sex, bone density, PSBCV, and PSBCV/VCV% between the two groups were statistically significant (P < 0.05). Logistic regression analysis showed that there were correlations between sex, bone density, and PSBCV/VCV% and the presence of paravertebral cement leakage (P < 0.05). The ROC curve showed that the area under the curve of the PSBCV/VCV% for the diagnosis of cement leakage in the paravertebral vein was greater than 0.65, and P < 0.05, indicating a diagnostic value. The best cut-off point for the diagnosis of paravertebral cement leakage with the PSBCV/VCV% was 13.68%, with a sensitivity of 84.7% and specificity of 37.8%.

Conclusion

Sex, bone density, and PSBCV/VCV% are risk factors for cement leakage in the paravertebral veins after vertebroplasty for the treatment of OVCFs; the PSBCV/VCV% is strongly associated with paravertebral venous leakage, and the optimal PSBCV/VCV% is 13.68%. When the PSBCV/VCV% exceeds the optimal value, the risk of cement leakage in the paravertebral vein becomes significantly increased.

A Nomogram for Predicting the Residual Back Pain after Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures

OBJECTIVE

Current findings suggest that percutaneous vertebroplasty (PVP) is a suitable therapeutic approach for osteoporotic vertebral compression fractures (OVCFs). However, a significant minority of patients still experience residual back pain after PVP. The present retrospective study was designed to determine the risk factors for residual back pain after PVP and provides a nomogram for predicting the residual back pain after PVP.

METHODS

We retrospectively reviewed the medical records of patients with single-segment OVCFs who underwent bilateral percutaneous vertebroplasty. Patients were divided into group N and group R according to the postoperative VAS score. Group R is described as the VAS score of residual back pain ≥ 4. Pre- and postoperative factors that may affect back pain relief were evaluated between two groups. Univariate and multivariate logistic regression analysis were performed to identify risk factors affecting residual back pain after PVP. We provided a nomogram for predicting the residual back pain and used the receiver operating characteristic curve (ROC), concordance index (C-index), calibration curve, and decision curve analyses (DCA) to evaluate the prognostic performance.

RESULTS

Among 268 patients treated with PVP, 37 (13.81%) patients were classified postoperative residual back pain. The results of the multivariate logistical regression analysis showed that the presence of an intravertebral vacuum cleft (IVC) (OR 3.790, P=0.026), posterior fascia oedema (OR 3.965, P=0.022), severe paraspinal muscle degeneration (OR 5.804, P=0.01; OR 13.767, P < 0.001), and blocky cement distribution (OR 2.225, P=0.041) were independent risk factors for residual back pain after PVP. The AUC value was 0.780, suggesting that the predictive ability was excellent. The prediction nomogram presented good discrimination, with a C-index of 0.774 (0.696∼0.852) and was validated to be 0.752 through bootstrapping validation. The calibration curve of the nomogram demonstrated a good consistency between the probabilities predicted by the nomogram and the actual probabilities. The nomogram showed net benefits in the range from 0.06 to 0.66 in DCA.

CONCLUSIONS

The presence of IVC, posterior fascia oedema, blocky cement distribution, and severe paraspinal muscle degeneration were significant risk factors for residual back pain after PVP for OVCFs. Patients with OVCFs after PVP who have these risk factors should be carefully monitored for the possible development of residual back pain. We provide a nomogram for predicting the residual back pain after PVP.

Vertebroplasty for osteoporotic vertebral fracture

Appropriate care of patients with a recent painful osteoporotic vertebral fracture (VF) requires immobilisation, analgesics and spinal orthoses. Some VFs are however responsible for disabling pain and prolonged bed rest. In this context, vertebroplasty techniques have been proposed with a large benefit in case series and open-label randomised studies, but lack efficacy in three among four double-blind randomised studies. The objectives of the treatment of a recent painful VF are to relieve pain and to preserve mechanical conditions. With this in mind, we report an experts’ opinion paper on the indications for vertebroplasty and research agenda for clinical studies.

Clinical observation of two bone cement distribution modes after percutaneous vertebroplasty for osteoporotic vertebral compression fractures

Background

Current findings suggest that percutaneous vertebroplasty(PVP) is a suitable therapeutic approach for osteoporotic vertebral compression fractures (OVCFs). The present retrospective study aimed to investigate the differences in clinical efficacy and related complications between the two bone cement distribution modes.

Methods

We retrospectively reviewed the medical records of the patients with single-segment OVCFs who underwent bilateral percutaneous vertebroplasty. Patients were divided into blocky and spongy group according to the type of postoperative bone cement distribution. Clinical efficacy and related complications was compared between the two bone cement distribution modes on 24 h after the operation and last follow-up.

Results

A total of 329 patients with an average follow up time of 17.54 months were included. The blocky group included 131 patients, 109 females(83.2 %) and 22 males(16.8 %) with a median age of 72.69 ± 7.76 years, while the Spongy group was made up of 198 patients, 38 females(19.2 %) and 160 males(80.8 %) with a median age of 71.11 ± 7.36 years. The VAS and ODI after operation improved significantly in both two groups. The VAS and ODI in the spongy group was significantly lower than that in the blocky group, 24 h postoperatively, and at the last follow-up. There were 42 cases (12.8 %) of adjacent vertebral fractures, 26 cases (19.8 %) in the blocky group and 16 cases (8.1 %) in the spongy group. There were 57 cases (17.3 %) of bone cement leakage, 18 cases (13.7 %) in blocky group and 39 cases (19.7 %) in the spongy group. At 24 h postoperatively and at the last follow-up, local kyphosis and anterior vertebral height were significantly corrected in both groups, but gradually decreased over time, and the degree of correction was significantly higher in the spongy group than in the block group. The change of local kyphosis and loss of vertebral body height were also less severe in the spongy group at the last follow-up.

Conclusions

Compared with blocky group, spongy group can better maintain the height of the vertebral body, correct local kyphosis, reduce the risk of the vertebral body recompression, long-term pain and restore functions.

Risk Factors for Cement Leakage in Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures: An Analysis of 1456 Vertebrae Augmented by Low-Viscosity Bone Cement

STUDY DESIGN

Retrospective study.

OBJECTIVE

To identify risk factors for cement leakage in percutaneous vertebroplasty (PVP) using low-viscosity bone cement for osteoporotic vertebral compression fractures (OVCFs).

SUMMARY OF BACKGROUND DATA

Cement leakage is the most common complication for PVP and its risk factors have been discussed. However, data in previous series were heterogeneous. Additionally, relative smaller patient sample or more types of cement leakage classified in those studies made the results conflicting.

METHODS

A total of 1090 patients who underwent PVP with low-viscosity bone cement for OVCFs in 1456 levels between January 2016 and June 2019 were retrospectively reviewed. Parameters potentially affecting the occurrence of cement leakage were assessed using univariate and multivariate analyses. Cement leakage was assessed using postoperative computed tomography scanning, and classified into two types (cortical leakage and venous leakage) considering the mechanism.

RESULTS

The incidence of cortical and venous leakage were 20.3% (295/1456) and 56.2% (819/1456), respectively. Cortical disruption, basivertebral foramen were the strongest risk factors for cortical leakage (P = 0.000), venous leakage (P = 0.000), respectively. Greater cement volume is one risk factor for both cortical leakage and venous leakage. The intravertebral cleft, solid type of cement distribution were significant risk factors for cortical leakage, and they both were protective factors for venous leakage. For cortical leakage, older age and trauma were another two risk factors. For venous leakage, female was another one risk factor, and higher grade of fracture severity is the strongest protective factor.

CONCLUSION

Both cortical leakage and venous leakage are prevalent. Adequate known of risk factors could help balance the incidence of two type leakage in unique vertebra and reduce the incidence of leakage in general in PVP for OVCFs.Level of Evidence: 3.

Percutaneous mesh-container-plasty for osteoporotic thoracolumbar burst fractures: A prospective, nonrandomized comparative study

OBJECTIVE

This study aimed to compare the clinical and radiological results of percutaneous mesh-container-plasty (PMCP) versus percutaneous kyphoplasty (PKP) in the treatment of osteoporotic thoracolumbar burst fractures.

METHODS

A prospective study of 122 patients with osteoporotic thoracolumbar burst fractures was conducted. The patients were nonrandomly assigned to receive PKP (62; 16 men, 46 women) and PMCP (60; 14 men, 46 women). The epidemiological data, surgical outcomes, and clinical and radiological features were compared between the 2 groups. Cement leakage, height restoration, deformity correction, canal compromise, and cement distribution were calculated from the radiographs. Visual pain analog scale (VAS), the Oswestry disability index (ODI), and short-form 36 health survey domains role physical (SF-36 rp) and bodily pain (SF-36 bp) were calculated before surgery and immediately and 2 years after surgery.

RESULTS

Although VAS, ODI, SF-36 bp, and SF-36 rp scores improved from 7 (6-9), 71.28±16.38, 22 (0-32), and 25 (0-50) preoperatively to 2 (1-3), 20.02±8.97, 84 (84-84), and 75 (75-100) immediately postoperatively in the PMCP group (p<0.05) and from 7 (6-8), 71.40±13.52, 22 (10.5-31.75), and 25 (0-50) preoperatively to 2 (1-3), 21.78±11.21, 84 (84-84), and 75 (75-100) immediately postoperatively in the PKP group (p<0.05), there was no difference between the 2 groups. The mean cost in the PKP group was less than that in the PMCP group ($5109±231 vs. $6699±201, p<0.05). Anterior, middle, and posterior vertebral body height ratios in the PMCP group were greater than those in the PKP group postoperatively (88.44%±3.76% vs. 81.10%±11.78%, 86.15%±3.50% vs. 82.30%±11.02%, and 93.91%±3.01% vs. 91.43%±6.71%, respectively, p<0.05). The Cobb angle in the PMCP group was lower than that in the PKP group postoperatively (6.67°±4.39° vs. 8.99°±4.06°, p<0.05). Cement distribution in the PMCP group was higher than that in the PKP group (30.48%±5.62% vs. 27.18%±4.87%, p<0.05). Cement leakage was observed to be lesser in the PMCP group (2/60) than in the PKP group (10 vs. 62, p<0.05).

CONCLUSION

Both PKP and PMCP treatments seem to have significant ability in pain relief and functional recovery. Despite its higher cost, PMCP treatment may have a better inhibition ability of cement leakage, cement distribution, height restoration, and improvement in segmental kyphosis than PKP treatment for osteoporotic thoracolumbar burst fractures.

LEVEL OF EVIDENCE

Level II, Therapeutic Study.

[Short-term effectiveness comparison of unipedicular versus bipedicular percutaneous kyphoplasty for osteoporotic vertebral compression fractures with posterior wall broken]

Objective

To compare the short-term effectiveness and safety of unipedicular versus bipedicular percutaneous kyphoplasty (PKP) for osteoporotic vertebral compression fracture (OVCF) with posterior wall broken.

Methods

The clinical data of 68 patients with OVCF with posterior wall broken and without posterior ligament complex injury and spinal cord nerve injury between June 2013 and December 2018 were retrospectively analyzed. According to the different operative approaches, the patients were divided into two groups: group A (36 cases received PKP via bilateral pedicle puncture) and group B (32 cases received PKP via unilateral pedicle paracentesis). There was no significant difference between the two groups in gender, age, fracture vertebra distribution, time from injury to operation, preoperative pain visual analogue scale (VAS) score, Oswestry disability index (ODI), and height of injured vertebra ( P>0.05). The operation time, intraoperative fluoroscopy times, and bone cement volume were recorded and compared between the two groups. The VAS score and ODI score were used to evaluate the effectiveness before operation, at 1 day and 6 months after operation; the height of injured vertebra was measured on the lateral X-ray film, and the recovery height of injured vertebra at 1 day after operation and the loss height of injured vertebra at 6 months after operation were calculated; the intraoperative and postoperative complications of the two groups were recorded.

Results

The operation time, intraoperative fluoroscopy times, and bone cement volume of group B were significantly less than those of group A ( P<0.05). All patients were followed up 10-35 months, with an average of 18 months. During the operation, there were 2 cases (5.56%) of cement leakage in group A and 9 cases (28.13%) in group B, showing significant difference ( χ ²=4.808, P=0.028). There was no adverse reactions of bone cement, iatrogenic spinal cord injury, infection of puncture port, or other complications in the two groups. During the follow-up period, there were 3 cases (8.3%) of adjacent vertebral fractures in group A and 2 cases (6.3%) in group B, showing no significant difference between the two groups ( χ ²=0.027, P=0.869). The height of injured vertebra of the two groups at 1 day and 6 months after operation were significantly improved when compared with preoperative ones ( P<0.05). There was no significant difference in the height of injured vertebrae and the recovery height of injured vertebra at 1 day after operation between the two groups ( P>0.05). However, at 6 months after operation, the height of injured vertebra in group B was significantly lower than that in group A ( P<0.05), and the loss height of injured vertebra in group B was significantly higher than that in group A ( P<0.05). The VAS score and ODI score at 1 day and 6 months after operation were significantly improved when compared with preoperative ones in both groups ( P<0.05), but there was no significant difference between the two groups ( P>0.05).

Conclusion

Both bipedicular and unipedicular PKP can obtain satisfactory effectiveness for the treatment of OVCF with posterior wall broken, but the former may have advantages of lower cement leakage rate and less height loss.

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.

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.

Vesselplasty using the Mesh-Hold™ bone-filling container for the treatment of pathological vertebral fractures due to osteolytic metastases: A retrospective study

PURPOSE

To evaluate the clinical benefits and complications of vesselplasty using the Mesh-Hold™ bone-filling container in the treatment of vertebral osteolytic fractures.

METHODS

This was a retrospective study of patients with vertebral osteolytic pathological fractures treated by vesselplasty at Sichuan Cancer Hospital between 09/2014 and 01/2018. VAS¹ (Visual analog scale) scores and ODI² (Oswestry disability index) were recorded routinely 1 day preoperative, at 1 day, 1 month, 3 months, 6 months, and 1 year postoperation, and at the last follow-up. V1³ (The of bone cement injection volume) and V2⁴ (vertebral body osteolytic volume) were evaluated, and the R⁵ (ratio) of bone cement filling was obtained according to the V1/V2.

RESULTS

Sixty-three patients were included (105 segments with osteolytic fractures). The amount of bone cement for each vertebra was 2.4-5.2 ml (3.1 ± 0.7 ml). The ratio (R) of bone cement filling was not related to pain relief or functional recovery (all P > 0.05).The VAS scores and ODI at different time points after surgery were decreased compared with before surgery (all P < 0.05). The bone cement leakage rate was 16.2 % (17/105). The follow-up was 4-30 months (mean of 13 ± 6 months). Thirty patients had died by the last follow-up, all from their cancer.

CONCLUSIONS

The Mesh-Hold™ bone-filling container in the treatment of vertebral fractures induced by osteolytic metastases could reduce pain, improve function, and reduce the bone cement leakage rate in the process of vesselplasty.

Effectiveness of percutaneous cement injection on proximal junctional failure after posterior lumbar interbody fusion: Preliminary study

Proximal junctional failure (PJF) is the greatest challenge after posterior lumbar interbody fusion (PLIF). The aim of this study was to evaluate the effectiveness of percutaneous cement injection (PCI) for PJF after PLIF patients requiring surgical revision.In this retrospective clinical study, we reviewed 7 patients requiring surgical revision for PJF after PLIF with 18 months follow-up. They received PCI at the collapsed vertebral body and supra-adjacent vertebra, with or without intervertebral disc intervention. The outcome measures were radiographic findings and revision surgery. Two different radiographic parameters (wedging rate (%) of the fractured vertebral body and local kyphosis angle) were used, and were performed before and immediately after PCI, and 18 month after the PCI.In our study, we showed that 5 of 7 patients who experienced PJF after PLIF did not receive any revision surgery after PCI. Immediately after cement injection, the anterior wedging rate (%) and the local kyphosis angle were significantly improved (P = .018, P = .028). The anterior wedging rates (%) and local kyphosis angle, at pre-PCI, immediate after PCI, and at final follow-up, were not significantly different between the non-revision surgery and revision surgery groups.Five of 7 patients who experienced PJF after PLIF did not receive revision surgery after PCI. Considering that general anesthesia and open surgery are high-risk procedures for geriatric patients, our results suggest that non-surgical PCI could be a viable alternative treatment option for PJF.SMC2017-01-011-001. Retrospectively registered 18 January 2017.

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

STUDY DESIGN

A prospective randomized study.

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Objective

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

Methods

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

Results

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

Conclusions

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

Vertebroplasty for acute painful osteoporotic vertebral compression fractures: An update

Vertebral compression fractures (VCFs) are a common cause of back pain and disability and are usually osteoporotic in nature. Therapy aims to adequately control pain and allow early mobilisation and return of function while preventing additional fractures. A proportion of patients do not achieve adequate pain relief using conservative measures alone. Unwanted adverse effects from medications may also ensue. Vertebroplasty represents an alternative treatment option for VCFs. Patients with acute VCFs (≤6 weeks old) may gain the most benefit from vertebroplasty as healed fractures are not as amenable to cement injection. High-quality studies have reported conflicting results regarding the use of vertebroplasty in the treatment of acute VCFs. Despite high-quality evidence, varying study designs and heterogenous patient cohorts make interpretation of this data difficult. Only one sham-controlled randomised controlled trial (RCT) has evaluated vertebroplasty exclusively in patients with acute VCFs, reporting favourable results. Pooled data from RCTs also suggest vertebroplasty to be safe. This article provides a concise and critical review of the current literature regarding vertebroplasty for the treatment of acute VCFs.

Utilization of the directional balloon technique to improve the effectiveness of percutaneous kyphoplasty in the treatment of osteoporotic vertebral compression fractures and reduction of bone cement leakage

BACKGROUND

This article evaluates the effectiveness of a new directional balloon technique in the treatment of osteoporotic vertebral compression fractures (OVCFs).

METHODS

From September 2015 to April 2017, 100 patients with single-segment OVCFs treated using percutaneous kyphoplasty were available for complete data assessment. Among these, 51 cases were treated with the traditional nondirectional balloon technique (group 1) and 49 cases were treated with the directional balloon technique (group 2). Operative time, blood loss, and X-ray exposure time were compared between the 2 groups. The visual analogue score (VAS), Oswestry disability index (ODI), and Roland Morris disability (RMD) scores, and wedge-shaped and kyphosis angles were measured at 3 days and 1, 3, 6, and 12 months, respectively, after surgery.

RESULTS

There were no significant differences in blood loss or the amount of bone cement injected between the 2 groups; however, operative times, X-ray exposure times, and leakage rates of bone cement, especially type C in group 2, were significantly lower in group 2 than those in group 1. VAS, ODI, and RMD scores, and wedge-shaped and kyphosis angles at each time point after surgery were significantly higher than those before surgery. However, the improvement in VAS, ODI, and RMD scores in group 2 was only significantly better than those in group 1 at 3 days after surgery.

CONCLUSION

The utilization of the directional balloon technique in the treatment of OVCFs using percutaneous kyphoplasty can not only reduce the operation time, the radiation, and the bone cement leakage, but also improve the early curative effect.

Influence of vertebral bone mineral density on total dispersion volume of bone cement in vertebroplasty

The aim of this study was to investigate the influence of vertebral bone mineral density (BMD) on total diffusion volume of bone cement in percutaneous vertebroplasty (PVP). This study was a retrospective review of prospectively collected data of consecutive patients with A1.2 thoracolumbar compression fractures treated by PVP. Vertebral BMD was measured before surgery and participants were divided into 3 groups according to World Health Organization diagnostic criteria for osteoporosis: Group A (normal BMD), Group B (reduced BMD), and Group C (osteoporosis). All vertebrae were injected with 3 mL of bone cement via the unilateral pedicle and scanned by computed tomography after surgery. Actual injection volume (bone cement only) and total diffusion volume (bone cement plus trabeculae and space) were calculated. Pain severity was determined by the visual analog scale before surgery and at both 1 day and 1 month after surgery. There were no significant differences in injection volume among the groups (P > .05), but the total dispersion volume was greater than injection volume in all groups (P < .05). Pairwise comparison showed a significant difference in total diffusion volume of bone cement between groups, with Group A having the largest volume and Group C the smallest volume. Pain was significantly reduced 1 day after surgery in each group compared with before surgery, but there were no significant between-group differences at 1 day or 1 month. Increasing vertebral BMD was positively correlated with increasing total diffusion volume. BMD does not significantly affect pain relief, despite producing a significantly lower distribution volume in osteoporotic patients.

Analysis of Risk Factors for New Vertebral Fracture After Percutaneous Vertebroplasty

STUDY DESIGN

Retrospective analysis. Level of evidence III.

OBJECTIVES

Low-energy vertebral compression fractures are an increasing socioeconomic problem among elderly patients. Percutaneous vertebroplasty has been extensively used for the treatment of painful fractures because of its effectiveness. However, some complications have been described; among them, new vertebral compression fractures, whether adjacent or not to the treated vertebra, are commonly reported complications (8% to 52%).

METHODS

We retrospectively analyzed epidemiological and technical variables presumably associated with new vertebral compression fractures. To determine the relationship between new vertebral compression fracture and percutaneous vertebroplasty, 30 patients (study group) with this complication were compared with 60 patients treated with percutaneous vertebroplasty without this condition (control group).

RESULTS

A higher cement percentage was found in the study group (40.3%) compared with the control group (30.5%). Initial vertebral kyphosis was significantly higher in the first group (15°) compared with the control group (9°). Epidemiological factors were similar in both groups.

CONCLUSIONS

In our study, increased cement percentage injected and a higher kyphosis were associated with new vertebral compression fractures.

The Optimal Volume Fraction in Percutaneous Vertebroplasty Evaluated by Pain Relief, Cement Dispersion, and Cement Leakage: A Prospective Cohort Study of 130 Patients with Painful Osteoporotic Vertebral Compression Fracture in the Thoracolumbar Vertebra

OBJECTIVE

To probe the relationship among cement volume/fraction, imaging features of cement distribution, and pain relief and then to evaluate the optimal volume during percutaneous vertebroplasty.

METHODS

From January 2014 to January 2017, a total of 130 patients eligible for inclusion criteria were enrolled in this prospective cohort study. According to the different degrees of pain relief, cement leakage, and cement distribution, all patients were allocated to 2 groups. Clinical and radiologic characteristics were assessed to identify independent factors influencing pain relief, cement leakage, and cement distribution, including age, sex, fracture age, bone mineral density, operation time, fracture level, fracture type, modified semiquantitative severity grade, intravertebral cleft, cortical disruption in the vertebral wall, endplate disruption, type of nutrient foramen, fractured vertebral body volume, intravertebral cement volume, and volume fraction. A receiver operating characteristic curve was used to analyze the diagnostic value of the cement volume/fraction and then to obtain the optional cut-off value.

RESULTS

The preoperative visual analog scale scores in the responders versus nonresponders patient groups were 7.37 ± 0.61 versus 7.87 ± 0.92 and the postoperative VAS scores in the responders versus nonresponders were 2.04 ± 0.61 versus 4.33 ± 0.49 at 1 week. There were no independent factors influencing pain relief. There were 95 (73.08%) patients who experienced cement leakage, and cortical disruption in the vertebral wall and cement fraction percentage were identified as independent risk factors by binary logistic regression analysis (adjusted odds ratio [OR] 2.935, 95% confidence interval [95% CI] 1.214-7.092, P = 0.017); (adjusted OR 1.134, 95% CI 1.026-1.254, P = 0.014). The area under the receiver-operating characteristic curve of volume fraction (VF%) was 0.658 (95% CI 0.549-0.768, P = 0.006 < 0.05). The cut-off value of VF% for cement leakage was 21.545%, with a sensitivity of 69.50% and a specificity of 60.00%. The incidence of favorable cement distribution was 74.62% (97/130), and VF% were identified as independent protective factors (adjusted OR 1.185, 95% CI 1.067-1.317, P = 0.002) The area under the receiver-operating characteristic curve of VF% was 0.686 (95% CI 0.571-0.802, P = 0.001 < 0.05). The cut-off value of VF% to reach a favorable cement distribution was 19.78%, with a sensitivity of 86.60% and a specificity of 51.50%.

CONCLUSIONS

In osteoporotic vertebral compression fracture with mild/moderate fracture severity at the single thoracolumbar level, the intravertebral cement volume of 4-6 mL could relieve pain rapidly. The optimal VF% was 19.78%, which could achieve satisfactory cement distribution. With the increase of VF%, the incidence of cement leakage would also increase.

Vertebroplasty and Kyphoplasty for Osteoporotic Vertebral Fractures: What Are the Latest Data?

Osteoporotic vertebral compression fractures frequently result in significant morbidity and health care resource use. For patients with severe and disabling pain, vertebral augmentation (vertebroplasty and kyphoplasty) is often considered. Although vertebroplasty was introduced >30 years ago, there are conflicting opinions regarding the role of these procedures in the treatment of osteoporotic vertebral compression fractures. This review article updates clinicians on the published prospective randomized controlled data, including the most recent positive trials that followed initial negative trials in 2009. Analysis of multiple national claim datasets has also provided further insight into the utility of these procedures. Finally, we considered the recent recommendations of national organizations and medical societies that advise on the use of vertebral augmentation procedures for osteoporotic vertebral compression fractures.

Is Balloon kyphoplasty a better treatment than percutaneous vertebroplasty for chronic obstructive pulmonary disease (COPD) patients with osteoporotic vertebral compression fractures (OVCFs)?

BACKGROUND

Although several studies reported that Balloon kyphoplasty (BK) or percutaneous vertebroplasty (PVP) could improve pulmonary functions, there is no study to compare the efficacy and safety of 2 procedures in COPD patients with osteoporotic vertebral compression fractures (OVCFs) and investigate the reason why they could improve pulmonary functions.

METHOD

Two procedures, including BK and PVP were performed in 61 COPD patients with single-level OVCFS. VAS-score, ODI, pulmonary function and radiological parameters (Anterior vertebral body height ratio, posterior vertebral body height ratio and Local kyphotic angle) were evaluated preoperatively and 1 week, 3 months and 12 moths postoperatively, respectively. The operation time and cement leakage rate were also recorded.

RESULT

The operation time was longer in BK than PVP (37.5 ± 7.4 versus 27.6 ± 6.2 min per vertebra). Both groups got an equally significant improvement in pain relief, functional result, pulmonary functions and demonstrated similar cement leakage rate (BK: 6.5%; PVP: 10%). Radiologically, BK is favored than PVP. A significant relationship between VAS and pulmonary functions except FEV₁ was observed in first week postoperatively, while the ODI was related to MVV in first 3 months postoperatively.

CONCLUSION

Both BK and PVP provided equally significant back pain relief and improvements of respiratory functions in patients affected by COPD with single level OVCFs. BK was favored in radiography, this improvement was not related to pain relief and improvement of pulmonary functions. Given much higher cost of BK, similar effectiveness and safety of BK and PVP, in COPD patients with OVCFs, PVP may be a better choice.

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

STUDY DESIGN

A retrospective study.

SUMMARY OF BACKGROUND DATA

Complications of the bone cement used in vertebroplasty and kyphoplasty procedures have received increasingly more attention, especially for bone cement volume.

OBJECTIVE

The aim of the study was to retrospectively assess the relationship between bone cement volume fraction and adjacent vertebral fracture (AVF) after unilateral percutaneous kyphoplasty (PKP).

MATERIALS AND METHODS

Between 2006 and 2011, 495 patients with single-level osteoporotic vertebral compression fracture (OVCF) were surgically treated by unilateral PKP and had completed 12-month follow-up in our hospital. According to the new OVCF, they were divided into 3 groups: AVF group, non-AVF group, and normal group (who were not new OVCF). On the basis of the value of the plain radiography, the cement volume fraction for the vertebral body was calculated, and cement leakage, bone mineral density, visual analog scale, and Cobb angle of preoperative and postoperative were analyzed.

RESULTS

During the follow-up, 110 (22.2%) patients had new OVCF, and others were normal (n=385). Fifty-two cases were AVF and 58 were non-AVF. The cement volume fraction of AVF group, non-AVF group, and normal group were 32.5%±5.5%, 27.3%±1.8%, and 27.1%±2.6%, respectively. The 95% confidence interval of volume fraction were (31.0, 34.1), (26.8, 27.7), and (26.9, 28.5), respectively. The AVF group showed higher cement volume fraction in 3 groups (P<0.05), and there were no significant difference between non-AVF and normal group (P>0.05). There were 19 (36.5%) patients with cement leakage in AVF group, 12 (20.7%) in non-AVF group, and 68 (17.7%) in normal group. The AVF group showed higher cement leakage (P<0.05). Compared with AVF group and normal group, non-AVF group had lower bone mineral density in preoperation. All groups reported significantly improved visual analog scale scores and Cobb angle on the day of surgery. However, there were no significant difference between the 3 groups.

CONCLUSIONS

Unilateral PKP is an effective and safe procedure for patients with OVCF. However, cement volume should be determined in terms of the vertebral body fraction to obtain a favorable outcome. The risk of AVF and cement leakage will increase obviously with the cement volume fraction increased. We recommend that a bone cement volume fraction of about one fourth is suitable for unilateral PKP.

Is There a Dose-Response Relationship of Cement Volume With Cement Leakage and Pain Relief After Vertebroplasty?

The aim of this study was to determine if there were dose–response relationships of cement volume with cement leakage and pain relief after percutaneous vertebroplasty (PVP) for osteoporosis vertebral compression fractures (OVCFs). We collected the patient and procedural characteristics on 108 patients with OVCFs in our hospital who received PVP. Univariate and multivariate analyses were performed to explore the relationships between these potential influential variables and cement leakage and pain relief at 1 month postoperatively. Multivariate linear and logistic regression analyses were conducted with the pain score reduction and the bone cement leakage as dependent variables and the potential risk factors as independent variables, respectively. The results showed that the independent risk factors for the pain relief were the cement volume injected and fracture age, and for bone cement leakage were the cement volume injected and low-viscosity cement. In conclusion, the present study indicated that there were positive dose–response correlation relationships of cement volume with the incidence of cement leakage and the degree of pain relief after PVP, respectively. Thus, the cement should be injected into the vertebrae as much as possible during the PVP procedure.

Decreased extrusion of calcium phosphate cement versus high viscosity PMMA cement into spongious bone marrow-an ex vivo and in vivo study in sheep vertebrae

BACKGROUND CONTEXT

Vertebroplasty or kyphoplasty of osteoporotic vertebral fractures bears the risk of pulmonary cement embolism (3.5%-23%) caused by leakage of commonly applied acrylic polymethylmethacrylate (PMMA) cement to spongious bone marrow or outside of the vertebrae. Ultraviscous cement and specific augmentation systems have been developed to reduce such adverse effects. Rapidly setting, resorbable, physiological calcium phosphate cement (CPC) may also represent a suitable alternative.

PURPOSE

This study aimed to compare the intravertebral extrusion of CPC and PMMA cement in an ex vivo and in vivo study in sheep.

STUDY DESIGN/SETTING

A prospective experimental animal study was carried out.

METHODS

Defects (diameter 5 mm; 15 mm depth) were created by a ventrolateral percutaneous approach in lumbar vertebrae of female Merino sheep (2-4 years) either ex vivo (n=17) or in vivo (n=6), and injected with: (1) CPC (L3); (2) CPC reinforced with 10% poly(l-lactide-co-glycolide) (PLGA) fibers (L4); or (3) PMMA cement (L5; Kyphon HV-R). Controls were untouched (L1) or empty defects (L2). The effects of the cement injections were assessed in vivo by blood gas analysis and ex vivo by computed tomography (CT), micro-CT (voxel size: 67 µm), histology, and biomechanical testing.

RESULTS

Following ex vivo injection, micro-CT documented significantly increased extrusion of PMMA cement in comparison to CPC (+/- fibers) starting at a distance of 1 mm from the edge of the defect (confirmed by histology); this was also demonstrated by micro-CT following in vivo cement injection. In addition, blood gas analysis showed consistently significantly lower values for the fraction of oxygenized hemoglobin/total hemoglobin (FO₂Hb) in the arterial blood until 25 minutes following injection of the PMMA cement (p ≤ .05 vs. CPC; 7, 15 minutes). Biomechanical testing following ex vivo injection showed significantly lower compressive strength and Young modulus than untouched controls for the empty defect (40% and 34% reduction, respectively) and all three cement-injected defects (21%-27% and 29%-32% reduction, respectively), without significant differences among the cements.

CONCLUSIONS

Because of comparable compressive strength, but significantly lower cement extrusion into spongious bone marrow than PMMA cement, physiological CPC (+/- PLGA fibers) may represent an attractive alternative to PMMA for vertebroplasty or kyphoplasty of osteoporotic vertebral fractures to reduce the frequency or severity of adverse effects.

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

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