Phenotypic changes in low-density lipoprotein particles as markers of adverse clinical outcomes in COVID-19

BACKGROUND AND AIMS

Low-density lipoprotein (LDL) plasma concentration decline is a biomarker for acute inflammatory diseases, including coronavirus disease-2019 (COVID-19). Phenotypic changes in LDL during COVID-19 may be equally related to adverse clinical outcomes.

METHODS

Individuals hospitalized due to COVID-19 (n = 40) were enrolled. Blood samples were collected on days 0, 2, 4, 6, and 30 (D0, D2, D4, D6, and D30). Oxidized LDL (ox-LDL), and lipoprotein-associated phospholipase A2 (Lp-PLA2) activity were measured. In a consecutive series of cases (n = 13), LDL was isolated by gradient ultracentrifugation from D0 and D6 and was quantified by lipidomic analysis. Association between clinical outcomes and LDL phenotypic changes was investigated.

RESULTS

In the first 30 days, 42.5% of participants died due to Covid-19. The serum ox-LDL increased from D0 to D6 (p < 0.005) and decreased at D30. Moreover, individuals who had an ox-LDL increase from D0 to D6 to over the 90th percentile died. The plasma Lp-PLA2 activity also increased progressively from D0 to D30 (p < 0.005), and the change from D0 to D6 in Lp-PLA2 and ox-LDL were positively correlated (r = 0.65, p < 0.0001). An exploratory untargeted lipidomic analysis uncovered 308 individual lipids in isolated LDL particles. Paired-test analysis from D0 and D6 revealed higher concentrations of 32 lipid species during disease progression, mainly represented by lysophosphatidyl choline and phosphatidylinositol. In addition, 69 lipid species were exclusively modulated in the LDL particles from non-survivors as compared to survivors.

CONCLUSIONS

Phenotypic changes in LDL particles are associated with disease progression and adverse clinical outcomes in COVID-19 patients and could serve as a potential prognostic biomarker.

Vaccine hesitancy educational tools for healthcare providers and trainees: A scoping review

In the era of vaccine hesitancy, highlighted by the current SARS-CoV2 pandemic, there is an acute need to develop an approach to reduce and address apprehension towards vaccinations. We sought to map and present an overview of existing educational interventions for healthcare providers (HCPs) on strategies to engage in effective vaccine discussion. We applied the Joanna Briggs Institute methodology framework in this scoping review. We searched five relevant databases (MEDLINE, CINAHL, EMBASE, PsycInfo, and SCOPUS) and grey literature through the Google search engine using keywords and subject headings that were systematically identified. We identified 3384 citations in peer-reviewed literature and 41 citations in grey literature. After screening for our inclusion criteria, we included 28 citations from peer reviewed literature and 16 citations from grey literature for analysis. We identified a total of 41 unique education interventions. Interventions were available from multiple disciplines, training levels, clinical settings, and diseases/vaccines. Interventions predominantly centered around two foci: knowledge sharing and communication training. Most interventions identified from peer-reviewed literature were facilitated and were applied with multiple modes of delivery. Interventions from grey literature were more topical and generally self-directed. We identified several gaps in knowledge. Firstly, accessibility and generalizability of interventions was limited. Secondly, distribution of interventions did not adequately address nursing and pharmacy disciplines, and did not cover the breadth of medical specialties for whom vaccine discussions apply. Thirdly, no interventions addressed self monitoring and the clinicians' recognition and management of emotions during difficult conversations. There is a need to address this gap and provide available, credible and comprehensive educational interventions that will support our healthcare providers in effective communication with vaccine hesitant patients.

Avasopasem manganese (GC4419) protects against cisplatin-induced chronic kidney disease: An exploratory analysis of renal metrics from a randomized phase 2b clinical trial in head and neck cancer patients

Head and neck squamous cell carcinoma (HNSCC) patients treated with high-dose cisplatin concurrently with radiotherapy (hdCis-RT) commonly suffer kidney injury leading to acute and chronic kidney disease (AKD and CKD, respectively). We conducted a retrospective analysis of renal function and kidney injury-related plasma biomarkers in a subset of HNSCC subjects receiving hdCis-RT in a double-blinded, placebo-controlled clinical trial (NCT02508389) evaluating the superoxide dismutase mimetic, avasopasem manganese (AVA), an investigational new drug. We found that 90 mg AVA treatment prevented a significant reduction in estimated glomerular filtration rate (eGFR) three months as well as six and twelve months after treatment compared to 30 mg AVA and placebo. Moreover, AVA treatment may have allowed renal repair in the first 22 days following cisplatin treatment as evidenced by an increase in epithelial growth factor (EGF), known to aid in renal recovery. An upward trend was also observed in plasma iron homeostasis proteins including total iron (Fe-blood) and iron saturation (Fe-saturation) in the 90 mg AVA group versus placebo. These data support the hypothesis that treatment with 90 mg AVA mitigates cisplatin-induced CKD by inhibiting hdCis-induced renal changes and promoting renal recovery.

Contactless skin perfusion monitoring with video cameras: tracking pharmacological vasoconstriction and vasodilation using photoplethysmographic changes

Objectives.Clinical assessment of skin perfusion informs prognosis in critically ill patients. Video camera monitoring could provide an objective, continuous method to monitor skin perfusion. In this prospective, interventional study of healthy volunteers, we tested whether video camera-derived photoplethysmography imaging and colour measurements could detect drug-induced skin perfusion changes.Approach.We monitored the lower limbs of 30 volunteers using video cameras while administering phenylephrine (a vasoconstrictor) and glyceryl trinitrate (a vasodilator). We report relative pixel intensity changes from baseline, as absolute values are sensitive to environmental factors. The primary outcome was the pre- to peak- infusion green channel amplitude change in the pulsatile PPGi waveform component. Secondary outcomes were pre-to-peak changes in the photoplethysmographic imaging waveform baseline, skin colour hue and skin colour saturation.Main results.The 30 participants had a median age of 29 years (IQR 25-34), sixteen (53%) were male. A 34.7% (p= 0.0001) mean decrease in the amplitude of the pulsatile photoplethysmographic imaging waveform occurred following phenylephrine infusion. A 30.7% (p= 0.000004) mean increase occurred following glyceryl trinitrate infusion. The photoplethysmographic imaging baseline decreased with phenylephrine by 2.1% (p= 0.000 02) and increased with glyceryl trinitrate by 0.5% (p= 0.026). Skin colour hue changed in opposite direction with phenylephrine (-0.0013,p= 0.0002) and glyceryl trinitrate (+0.0006,p= 0.019). Skin colour saturation decreased with phenylephrine by 0.0022 (p= 0.0002), with no significant change observed with glyceryl trinitrate (+0.0005,p= 0.21).Significance.Drug-induced vasoconstriction and vasodilation are associated with detectable changes in photoplethysmographic imaging waveform parameters and skin hue. Our findings suggest video cameras have great potential for continuous, contactless skin perfusion monitoring.

The impact of cultural stress and gender norms on alcohol use severity among Latino immigrant men

Alcohol misuse affects 15 million people in the United States. Compared to White men, Latino men have disproportionately higher rates of both alcohol misuse and negative alcohol-related consequences (e.g. drunk driving, liver disease, alcohol dependence, HIV/AIDS). This cross sectional study examined how cultural stressors [immigration stress and negative context of reception (NCR)] coupled with traditional Latino male gender norms (machismo and caballerismo) influences alcohol use severity (AUS) among adult Latino immigrant men. Data for the present study was collected between 2017 and 2018 from 279 Cuban, Central American, and South American adult Latino men who immigrated to the US approximately 10 years prior. Results from hierarchical multiple regression analysis revealed higher levels of perceived NCR (β = 0.15, p  = .01), and machismo (β = 0.16, p = .02) were associated with greater AUS. Significant interaction effects were found between both cultural stressors and machismo [immigration stress x machismo (β = 0.22, p < .001); NCR x machismo (β = 0.22, p < .001)] whereby higher levels of machismo strengthened the association between cultural stress and AUS. Findings from the present study can inform culturally appropriate interventions aimed at mitigating alcohol use among Latino immigrant men.

Abstract 197: Proteomic Characterization Of Human Brain Lipoproteins Speciated By Size Exclusion Chromatography

Like plasma, the cerebrospinal fluid (CSF) contains lipid-protein complexes called lipoproteins tasked with transporting lipids and protecting against cerebrovascular dysfunction. These brain lipoproteins (BLps) are generated de novo in the central nervous system (CNS), but little is known about them, because they exist in CSF at <0.5% the concentration of lipoproteins in plasma making them difficult to study. BLps are thought to resemble plasma high-density lipoproteins (HDL), a heterogenous population of compositionally distinct particles important for transporting lipid, protecting against oxidative stress, and modulating immune and inflammatory responses in the periphery. Mass spectrometry (LC-MS/MS) studies have shown that 260 different proteins can interact with different HDLs in the periphery and specific combinations of these proteins cluster on the lipid surface to govern particle function. In the current study, we developed a lipoprotein profiling technology that overcomes the BLp abundance problem in CSF to capture BLp subspecies with unprecedented sensitivity and resolution. Using high-resolution size exclusion chromatography, we identified at least 10 distinctly sized BLp populations in human CSF with a majority of the particles eluting in size ranges between plasma low-density lipoproteins (LDL) and HDL. BLps were isolated from fractionated CSF using a lipid-binding resin. Proteomic analysis of the particles using LC-MS/MS identified 299 different lipid-associated proteins across fractions with 189 of those proteins not currently reported on the human HDL Proteome Watch. Co-migration analysis further revealed at least 27 unique protein communities across the fractions indicating that multiple distinct subspecies exist within the same sized subfractions. DAVID functional analysis shows that the communities are highly enriched in proteins important in the immune response and neurometabolic functions such as neuron generation and development. In summary, our study shows that similar to plasma HDL, BLps are a highly speciated population of compositionally distinct particles but are enriched in CNS-derived proteins that are essential for maintaining cognitive health.

Abstract 193: Apolipoprotein A-I Rotamers Determine The Size And Cholesterol Efflux Capacity Of High-Density Lipoprotein

Cardiovascular disease (CVD) risk is strongly and inversely associated with plasma levels of high-density lipoprotein cholesterol (HDL-C). Recent clinical studies suggest that the association between HDL-C and CVD risk is indirect and that HDL’s cardioprotective function may be attributed to its ability to promote cholesterol efflux from macrophages. Apolipoprotein A-I (APOA1), the major protein in HDL, serves as a structural scaffold to facilitate protein binding and enzyme activation. Our previous work demonstrated that two or three molecules of APOA1 form antiparallel dimer structures (rotamers) that wrap around discoidal and spherical HDL. Human HDL contains both LL5/5 and LL5/4 rotamers. Because little is known about the impact of different rotamers on HDL function, we generated human APOA1 mutants with single cysteine mutations that produced reconstituted HDL (rHDL) locked in specific rotamer (K133C for LL5/5 and L122C for LL5/4). The LL5/5 rotamer of rHDL demonstrated four-fold higher LCAT activation efficiency than the LL5/4 rotamer. To investigate the roles of APOA1 rotamers in vivo , we used a liver-targeted adeno-associated virus (AAV) to express WT hAPOA1 and the two cysteine mutants in APOA1-deficient ( Apoa1 -/- ) mice. HDL particle concentration (HDL-P) in WT and LL5/5 mice were similar but were 250% higher (n=8; P<0.0001) than those of LL5/4 mice. Importantly, mice expressing different APOA1 rotamers had markedly different HDL size patterns: HDL in LL5/4 hAPOA1 mice consisted mainly of extra-small HDL (7.8 nm in diameter), consistent with our finding that the LL5/4 rotamer had a low efficiency in activating LCAT. HDL in WT and LL5/5 mice had the same size distribution with one major peak at 10 nm. LC-MS/MS analysis identified 48 HDL proteins. One-third of the proteins (including APOA2, APOC1, APOC3 and LCAT) differed significantly in relative abundance in the different rotamers. Importantly, on a per particle basis, HDL from LL5/4 mice demonstrated three times higher ABCA1 cholesterol efflux capacity than HDL from WT and LL5/5 mice. Our observations strongly suggest that APOA1 rotamers play distinct roles in HDL metabolism, raising the possibility that differences in APOA1 rotamer distribution alter the cardioprotective functions of HDL.

EP.WE.231Emergency Presentations of Colorectal Cancer during the COVID-19 Era

Aims

COVID-19 has reduced the ability to provide red flag investigations for colorectal patients. The aim of this study is to assess the number of emergency presentations of new colorectal malignancy during the COVID-19 era and if there is an increase in palliative cases.

Methods

A retrospective review of all patients presenting to unscheduled care with a new diagnosis of colorectal malignancy from 31st March 2020 - 25th January 2021 in a single UK Trust. An institutional data base and electronic care records were used to review patient demographics, management and curative intent. Data points for the same period in 2019-2020 were recorded for comparison.

Results

45 patients diagnosed with new colorectal malignancy during an unscheduled admission to hospital within the study timeframe. 22% (10/45) presented in January 2021. 29 diagnosed during the same time interval 2019-2020. Median age at presentation was 77.5 and 79 respectively.

40% (18/45) of patients in 2020-2021 proceeded to emergency surgery, compared to 58% (17/29) in 2019-2020 (p = 0.12).

10.3% (3/29) of 2019-2020 patients were managed with colonic stenting. This increased in 2020-2021 to 17.8% (8/45) (p = 0.38).

77.8% (35/45) patients in 2020/2021 presented at a palliative stage of disease compared to 62.1% (18/29) in 2019-2020 (p = 0.15).

Conclusions

Overall the data has not shown a statistically significant difference in patients presenting as an emergency with new colorectal malignancy. However, there was a rise in admissions noted in January 2021; should this trend continue, alongside the persistent pressures of COVID-19 ongoing research is needed to assess the true impact.

EP.WE.338Ambulatory Ultrasound Scans Reduce Inpatient Admissions During COVID-19: A Need for the Expansion of Ambulatory Services

Aim

With the increased need to manage patients out of hospital during COVID-19, it was anticipated that need for ambulatory imaging would increase. This study aimed to assess the demand for ambulatory ultrasounds (US) during the COVID-19 pandemic and the impact on inpatient admissions.

Methods

A retrospective review of patients presenting to the Emergency Department (ED) between 12^th July – 23^rd August 2020 who required an US as first line imaging. Electronic Care Records were used to collect data regarding type of US i.e., inpatient, or ambulatory, time taken for ambulatory US and outcome after imaging. The same period in 2019 was assessed for comparison.

Results

In 2020, 100 patients required an US compared to 88 in 2019. 37% (37/100) of which were discharged for an ambulatory US, compared to 14.8% (13/88) in 2019 (p = 0.006). The average waiting time for an ambulatory US in 2019 was 2 days, this increased to 7 days in 2020. Following ambulatory US in 2020 43.2% (16/37) required further outpatient imaging or assessment; similar outcomes were seen in 2019 with 46.2% (6/13). Overall, there was a 150% increase in the use of ambulatory US, with a 26% decrease in admissions in 2020 vs. 2019.

Conclusions

There was a significant increase in the number of patients discharged from ED to undergo an ambulatory US resulting in reduced inpatient admissions. This increase in demand is reflected by the prolonged waiting time highlighting the requirement for expansion of ambulatory services to meet this clinical need.

SP10.1.2 Increased Access to Computed Tomography Reduces Acute Surgical Admissions: Lessons Learnt During the COVID-19 Pandemic

Aim

With increased bed pressures due to COVID-19, keeping patients out of hospital became critical. Computed Tomography (CT) utilisation was increased to aid in the assessment of acute surgical patients. The aim of this study was to assess if increased access to CT reduced inpatient admissions.

Methods

A Retrospective audit of patients presenting to the Emergency Department (ED) between 12th July – 23rd August 2020 who required a CT scan. Data collected from Electronic Care Records and NIPACS, including patient destination at time of CT and decision following CT. For comparison, the same time-period in 2019 was assessed.

Results

In 2020, 301 patients required a CT compared to 207 in 2019. 84.7% (255/301) had a CT direct from ED in 2020 vs. 56.5% (117/207) in 2019 (p &lt; 0.001).

Of those who had CT direct from ED in 2020 18.4% (47/255) were discharged, compared to 1.7% (2/117) in 2019 (p &lt; 0.001). 9.8% (25/255) were directed to an alternative specialty in 2020 vs. 2.6% (3/117) in 2019 (p = 0.014).

2.7% (8/301) were discharged for an ambulatory CT in 2020, an increase from 0.5% (1/207) in 2019 (p = 0.07).

Overall, there was a 24% reduction in the number of patients requiring acute surgical admission in 2020 vs. 2019.

Conclusions

There was a significant increase in the number of CT’s carried out directly from ED. This enabled a significant number of patients to be discharged or transferred to a more appropriate specialty. These results demonstrate that increased access to CT can reduce the need for acute surgical admission.

miR-19a-3p containing exosomes improve function of ischaemic myocardium upon shock wave therapy

AIMS

As many current approaches for heart regeneration exert unfavourable side effects, the induction of endogenous repair mechanisms in ischaemic heart disease is of particular interest. Recently, exosomes carrying angiogenic miRNAs have been described to improve heart function. However, it remains challenging to stimulate specific release of reparative exosomes in ischaemic myocardium. In the present study, we sought to test the hypothesis that the physical stimulus of shock wave therapy (SWT) causes the release of exosomes. We aimed to substantiate the pro-angiogenic impact of the released factors, to identify the nature of their cargo, and to test their efficacy in vivo supporting regeneration and recovery after myocardial ischaemia.

METHODS AND RESULTS

Mechanical stimulation of ischaemic muscle via SWT caused extracellular vesicle (EV) release from endothelial cells both in vitro and in vivo. Characterization of EVs via electron microscopy, nanoparticle tracking analysis and flow cytometry revealed specific exosome morphology and size with the presence of exosome markers CD9, CD81, and CD63. Exosomes exhibited angiogenic properties activating protein kinase b (Akt) and extracellular-signal regulated kinase (ERK) resulting in enhanced endothelial tube formation and proliferation. A miRNA array and transcriptome analysis via next-generation sequencing were performed to specify exosome content. miR-19a-3p was identified as responsible cargo, antimir-19a-3p antagonized angiogenic exosome effects. Exosomes and target miRNA were injected intramyocardially in mice after left anterior descending artery ligation. Exosomes resulted in improved vascularization, decreased myocardial fibrosis, and increased left ventricular ejection fraction as shown by transthoracic echocardiography.

CONCLUSION

The mechanical stimulus of SWT causes release of angiogenic exosomes. miR-19a-3p is the vesicular cargo responsible for the observed effects. Released exosomes induce angiogenesis, decrease myocardial fibrosis, and improve left ventricular function after myocardial ischaemia. Exosome release via SWT could develop an innovative approach for the regeneration of ischaemic myocardium.

Centralized Clinical Trial Imaging Data Management: Practical Guidance from a Comprehensive Cancer Center's Experience

Medical imaging is an integral part of clinical trial research and it must be managed properly to provide accurate data to the sponsor in a timely manner (Clune in Cancer Inform 4:33-56, 2007; Wang et al. in Proc SPIE Int Soc Opt Eng 7967, 2011). Standardized workflows for site qualification, protocol preparation, data storage, retrieval, de-identification, submission, and query resolution are paramount to achieve quality clinical trial data management such as reducing the number of imaging protocol deviations and avoiding delays in data transfer. Centralization of data management and implementation of relational databases and electronic workflows can help maintain consistency and accuracy of imaging data. This technical note aims at sharing the practical implementation of our centralized clinical trial imaging data management processes to avoid the fragmentation of tasks among various disease centers and research staff, and enable us to provide quality, accurate, and timely imaging data to clinical trial sponsors.

Stroke Volume estimation using aortic pressure measurements and aortic cross sectional area: Proof of concept

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV.

A comparison between four techniques to measure cardiac output

Cardiac output is an important variable when monitoring hemodynamic status. In particular, changes in cardiac output represent the goal of several circulatory management therapies. Unfortunately, cardiac output is very difficult to estimate, either in experimental or clinical settings. The goal of this work is to compare four techniques to measure cardiac output: pressure-volume catheter, aortic flow probe, thermodilution, and the PiCCO monitor. These four techniques were simultaneously used during experiments of fluid and endotoxin administration on 7 pigs. Findings show that, first, each individual technique is precise, with a relative coefficient of repeatability lower than 7 %. Second, 1 cardiac output estimate provided by any technique relates poorly to the estimates from the other 3, even if there is only small bias between the techniques. Third, changes in cardiac output detected by one technique are only detected by the others in 62 to 100 % of cases. This study confirms the difficulty of obtaining a reliable clinical cardiac output measurement. Therefore, several measurements using different techniques should be performed, if possible, and all such should be treated with caution.

Abstract 201: Maternal HDL-Cholesterol Levels in Women From the Gambia are Directly Related to Infant Birthweight

Babies born with low birthweight are often at a health disadvantage. Previous studies have shown direct relationships between maternal plasma cholesterol and infant birthweight in resource-rich countries. As plasma cholesterol levels are often decreased in resource-poor countries, the purpose of these studies was to evaluate the relationship between plasma cholesterol and birthweight in women enrolled in the ENID trial (ISRCTN49285450) in rural Gambia, West Africa. Plasma was obtained at enrolment (13.6±3.3 wk) and at 20 and 30 weeks of gestation; samples were obtained from women with term infants that weighed <2.75 kg or >3.25 kg at birth. Women with lower HDL-cholesterol (HDL-C) concentrations in mid-pregnancy had lower birthweight infants compared to women with higher HDL-C concentrations. There was no significant association between LDL-C or total cholesterol concentrations and birthweight. The relationship with HDL-C and birthweight was maintained when maternal BMI was included in the model. To begin to elucidate the processes involved in the regulation of fetal growth, placental function was examined in mice with increasing maternal HDL-C concentrations based on apoA-I levels; mice were lacking apoA-I (apoA-I -/- ), were wildtype (apoA-I +/+ ), or had excess apoA-I (apoA-I tg/tg ). HDL decreased in size as plasma apoA-I levels increased, and there were no statistical differences in the proteins carried by HDL, except for apoA-I, in pregnant mice of different genotypes. However, pregnancy alone led to changes in the HDL proteome. Importantly, fetuses of mice with lower concentrations of maternal HDL-C had reduced growth rates, not due to a lack of fetal apoA-I. The murine fetal growth rates were directly related to nutrient uptake by and transport across the placenta. This work suggests that maternal HDL affects placental function leading to enhanced nutrient supply and improved growth in utero, making HDL a potential biomarker for fetal growth and putative target for intervention.

Comparison of the effect of two different bone-targeted radiofrequency ablation (RFA) systems alone and in combination with percutaneous vertebroplasty (PVP) on the biomechanical stability of the metastatic spine

INTRODUCTION

Radiofrequency ablation (RFA) and percutaneous vertebroplasty (PVP) are used independently and in combination to treat metastatically involved vertebrae with the aim of relieving pain, reducing tumour burden and providing bony mechanical stabilization.

PURPOSE

The aim of this work was to characterize the effect of two bone-targeted RFA devices, alone and in combination with PVP, to improve strength and mechanical stability in vertebrae with osteolytic metastatic disease.

METHODS

Simulated spinal metastases (n = 12) were treated with one of two bone-targeted RFA devices (bipolar cooled or bone coil RF electrodes), followed by PVP. Under axial compressive loading, spinal canal narrowing was measured in the intact specimen, after tumour simulation, post-RFA and post-PVP.

RESULTS

RFA alone resulted in successful tumour shrinkage and cavitation, but further increased canal narrowing under loading. RFA combined with PVP significantly reduced posterior wall stability in samples where sufficient tumour shrinkage and cavitation were coupled with a pattern of cement deposition which extended to posterior vertebral body.

CONCLUSIONS

RFA combined with cement deposition in the posterior vertebral body demonstrates significantly more stable vertebrae under axial loading.