Atherosclerotic Disease and its Relationship to Lumbar Degenerative Disk Disease, Facet Arthritis, and Stenosis With Computed Tomography Angiography

Association of Abdominal Aortic Calcification and Clinical Outcomes in LDH Patients Treated with Endoscopic Lumbar Discectomy

INTRODUCTION

To determine any significant associations between abdominal aortic calcification (AAC) and clinical manifestations of pain symptoms following endoscopic lumbar discectomy.

METHODS

Patients sequentially presenting with a history of unilateral radiculopathy with or without back pain, and with magnetic resonance imaging (MRI)-confirmed diagnosis of posterolateral disc herniation between August 2021 and December 2023 were eligible for inclusion in the study. All patients underwent endoscopic discectomy at our center during the study period. AAC stages were classified based on the Kauppila classification system using lateral lumbar radiographs.

RESULTS

Between August 2021 and December 2023 a total of 120 patients were included in the study for analysis, of whom 82 (68.3%) exhibited mild AAC and 38 (31.7%) had moderate-severe AAC. Analyses using the multivariate linear regression model revealed a significant correlation between AAC comorbidity and postoperative clinical outcomes. At 1 year post-surgery, the mean change in leg pain following endoscopic lumbar discectomy was significantly less for patients with moderate-severe AAC (5.0 points) than for patients with mild ACC (p < 0.001). Even after adjusting for relevant confounders, this difference remained significant. Similar results were also observed in the postoperative improvement of back pain, the Oswestry Disability Index score, and the physical functioning, role physical, and bodily pain components of the 36-item Short Form Health Survey questionnaire. There was no significant difference in the rate of repeat surgery or post-surgical new-onset back pain between patients with different levels of severity of AAC at 1 year post-surgery.

CONCLUSIONS

There is a significant association between the severity of AAC and clinical outcomes among patients with lumbar disk herniation who underwent endoscopic lumbar discectomy. AAC may serve as a prognostic factor in predicting surgical outcomes and guiding management strategies for patients with lumbar disk herniation following endoscopic lumbar discectomy.

Exploring lncRNA Expression Patterns in Patients With Hypertrophied Ligamentum Flavum

OBJECTIVE

Hypertrophy ligamentum flavum (LFH) is a common cause of lumbar spinal stenosis, resulting in significant disability and morbidity. Although long noncoding RNAs (lncRNAs) have been associated with various biological processes and disorders, their involvement in LFH remains not fully understood.

METHODS

Human ligamentum flavum samples were analyzed using lncRNA sequencing followed by validation through quantitative real-time polymerase chain reaction. To explore the potential biological functions of differentially expressed lncRNA-associated genes, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. We also studied the impact of lncRNA PARD3-AS1 on the progression of LFH in vitro.

RESULTS

In the LFH tissues when compared to that in the nonhypertrophic ligamentum flavum (LFN) tissues, a total of 1,091 lncRNAs exhibited differential expression, with 645 upregulated and 446 downregulated. Based on GO analysis, the differentially expressed transcripts primarily participated in metabolic processes, organelles, nuclear lumen, cytoplasm, protein binding, nucleic acid binding, and transcription factor activity. Moreover, KEGG pathway analysis indicated that the differentially expressed lncRNAs were associated with the hippo signaling pathway, nucleotide excision repair, and nuclear factor-kappa B signaling pathway. The expression of PARD3-AS1, RP11-430G17.3, RP1-193H18.3, and H19 was confirmed to be consistent with the sequencing analysis. Inhibition of PARD3-AS1 resulted in the suppression of fibrosis in LFH cells, whereas the overexpression of PARD3-AS1 promoted fibrosis in LFH cells in vitro.

CONCLUSION

This study identified distinct expression patterns of lncRNAs that are linked to LFH, providing insights into its underlying mechanisms and potential prognostic and therapeutic interventions. Notably, PARD3-AS1 appears to play a significant role in the pathophysiology of LFH.

Lumbar disc herniation is an independent predictor of plaque burden in the patients with unstable angina

Objective

Assessing the impact of lumbar disc herniation (LDH) on the plaque burden of coronary atherosclerosis is our objective.

Methods

In this study, a total of 212 patients (age 46-80 years) with unstable angina (UA) who underwent coronary angiography (CAG) in our hospital from January 2018 to July 2022 due to UA were included. Patients were divided into LDH group (n = 106) and no LDH group (n = 106). Gensini scores were calculated to assess the plaque burden of coronary. Logistic analysis was used to examine potential risk variables linked to the Gensini score. The association between lumbar disc lesions grading and coronary plaque burden was analysed by Spearman's correlation test. LDH patients with higher plaque burden (n = 56) were further divided into evolocumab treatment group (n = 28) and conventional treatment group (n = 28). Cox regression analysis were performed.

Results

Patients with LDH had higher Gensini scores (P < 0.01) and triglyceride (TG) levels (P = 0.04), but HDL-C (P = 0.01) levels were lower. LDH was found to be an independent risk factor for higher Gensini scores (OR = 2.38, P < 0.01) by logistic analysis. The Spearman's correlation test suggested that the degree of lumbar disc lesions was related to the Gensini score and the level of blood lipid. Cox regression analysis showed that evolocumab treatment could significantly reduce the composite MACE events (cardiac death, nonfatal myocardial infarction, nonfatal stroke, and readmission due to angina) (HR = 0.26, P = 0.04) in higher coronary plaque burden patients.

Conclusion

LDH is an independent risk factor for the higher coronary plaque burden. Evolocumab treatment significantly reduced the occurrence of cardiovascular events in LDH patients with higher plaque burden. Additionally, our data indicate that LDH is associated with increased blood lipid, which may contribute to the development of plaque burden.

Evidence of causal effects of blood pressure on back pain and back pain on type II diabetes provided by a bidirectional Mendelian randomization study

BACKGROUND CONTEXT

Cardiovascular risk factors (hypertension, dyslipidemia, and type II diabetes) have been proposed as risk factors for back pain. However, few longitudinal studies have found significant associations between cardiovascular risk factors and back pain, and these may be explained by confounding or reverse causation.

PURPOSE

To examine potential causal effects of cardiovascular risk factors on back pain, and vice versa.

STUDY DESIGN

Bidirectional Mendelian randomization (MR) study.

PATIENT SAMPLES

Genome-wide association studies (GWAS) with sample sizes between 173,082 and 1,028,947 participants.

OUTCOME MEASURES

Outcomes included (1) back pain associated with health care use (BP-HC) in the forward MR; and (2) seven cardiovascular phenotypes in the reverse MR, including 2 measurements used for the evaluation of hypertension (diastolic blood pressure and systolic blood pressure), 4 phenotypes related to dyslipidemia (LDL cholesterol, HDL cholesterol, total cholesterol, and triglycerides), and type II diabetes.

METHODS

We used summary statistics from large, publicly available GWAS for BP-HC and the 7 cardiovascular phenotypes to obtain genetic instrumental variables. We examined MR evidence for causal associations using inverse-variance weighted (IVW) analysis, Causal Analysis Using Summary Effect (CAUSE), and sensitivity analyses.

RESULTS

In forward MR analyses of seven cardiovascular phenotypes, diastolic blood pressure was associated with BP-HC across all analyses (IVW estimate: OR = 1.10 per 10.5 mm Hg increase [1.04-1.17], p-value = .001), and significant associations of systolic blood pressure with BP-HC were also found (IVW estimate: OR = 1.09 per 19.3 mm Hg increase [1.04-1.15], p-value = .0006). In reverse MR analyses, only type II diabetes was associated with BP-HC across all analyses (IVW estimate: OR = 1.40 [1.13-1.73], p-value = .002).

CONCLUSIONS

These findings from analyses of large, population-based samples indicate that higher blood pressure increases the risk of BP-HC, and BP-HC itself increases the risk of type II diabetes.

Identification and validation of hub genes and pathways associated with mitochondrial dysfunction in hypertrophy of ligamentum flavum

Background: Lumbar spinal stenosis which can lead to irreversible neurologic damage and functional disability, is characterized by hypertrophy of ligamentum flavum (HLF). Recent studies have indicated that mitochondrial dysfunction may contribute to the development of HLF. However, the underlying mechanism is still unclear. Methods: The dataset GSE113212 was obtained from the Gene Expression Omnibus database, and the differentially expressed genes were identified. The intersection of DEGs and mitochondrial dysfunction-related genes were identified as mitochondrial dysfunction-related DEGs. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Gene Set Enrichment Analysis were performed. Protein-protein interaction network was constructed, and miRNAs and transcriptional factors of the hub genes were predicted via the miRNet database. Small molecule drugs targeted to these hub genes were predicted via PubChem. Immune infiltration analysis was performed to evaluate the infiltration level of immune cells and their correlation with the hub genes. In final, we measured the mitochondrial function and oxidative stress in vitro and verified the expression of hub genes by qPCR experiments. Results: In total, 43 genes were identified as MDRDEGs. These genes were mainly involved in cellular oxidation, catabolic processes, and the integrity of mitochondrial structure and function. The top hub genes were screened, including LONP1, TK2, SCO2, DBT, TFAM, MFN2. The most significant enriched pathways include cytokine-cytokine receptor interaction, focal adhesion, etc. Besides, SP1, PPARGC1A, YY1, MYC, PPARG, and STAT1 were predicted transcriptional factors of these hub genes. Additionally, increased immune infiltration was demonstrated in HLF, with a close correlation between hub genes and immune cells found. The mitochondrial dysfunction and the expression of hub genes were validated by evaluation of mitochondrial DNA, oxidative stress markers and quantitative real-time PCR. Conclusion: This study applied the integrative bioinformatics analysis and revealed the mitochondrial dysfunction-related key genes, regulatory pathways, TFs, miRNAs, and small molecules underlying the development of HLF, which improved the understanding of molecular mechanisms and the development of novel therapeutic targets for HLF.

Predictors and Outcomes of Spinal Cord Injury following Complex Branched/Fenestrated Endovascular Aortic Repair in the US Aortic Research Consortium

OBJECTIVE

Spinal cord ischemia (SCI) is a well-known complication of thoracoabdominal aortic aneurysm (TAAA) repair and is associated with profound morbidity and mortality. The purpose of this study was to describe predictors for the development of SCI, as well as outcomes for patients who develop SCI, after branched/fenestrated endovascular aortic repair (FB-EVAR) in a large cohort of centers with adjudicated physician-sponsored investigational device exemption studies.

METHODS

We utilized a pooled dataset from 9 United States Aortic Research Consortium (US ARC) centers involved in investigational device exemption (IDE) trials for treatment of suprarenal and thoracoabdominal aortic aneurysms. SCI was defined as new transient weakness (paraparesis) or permanent paraplegia after repair without other potential neurologic etiologies. Multivariable analysis was performed to identify predictors of SCI, and life-table analysis and Kaplan-Meier methodology were used to evaluate survival differences.

RESULTS

A total of 1,681 patients underwent FB-EVAR over the period 2005-2020. The overall rate of SCI was 7.1% (3% transient and 4.1% permanent). Predictors of SCI on multivariable analysis were Crawford Extent I, II, and III distribution of aortic disease (OR 4.79 95% CI 4.77- 4.81, P<.001), age ≥70 (OR 1.64, 95% CI, 1.63-1.64, P=.029), packed red blood cell transfusion (OR 2.00, 95% CI, 1.99-2.00, P=.001), and history of PVD (OR 1.65, 95% CI, 1.64-1.65, P=.034). Median survival was significantly worse for patients with any degree of SCI compared to those without SCI (any SCI - 40.4 vs no SCI - 60.3 months, Log Rank <.001), and also worse in those with a permanent deficit (24.1 months) vs. those with a transient deficit (62.4 months) (Log Rank <0.001). One year survival for patients who developed no SCI was 90.8%, compared to 73.9% in patients who developed any SCI. When stratified by degree of deficit, survival was 84.8% at one year for those who developed paraparesis, and 66.2% for those who developed permanent deficits.

CONCLUSIONS

The overall rates of any SCI at 7.1% and permanent deficit at 4.1% observed in this study compare favorably to those reported in contemporary literature. Our findings confirm that increased length of aortic disease is associated with SCI and those with Crawford Extent I-III TAAAs are at highest risk. The long-term impact on patient mortality underscores the importance of preventive measures and rapid implementation of rescue protocols if and when deficits develop.

Impact of oxidized LDL/LOX-1 system on ligamentum flavum hypertrophy

BACKGROUND

Patients with lumbar spinal canal stenosis (LSS) often have peripheral arterial disease and aortic disease based on atherosclerosis. Oxidized LDL, which is clinically involved in the development of atherosclerosis, may also influence LF hypertrophy, but the function of the oxidized low-density lipoprotein (LDL)/lectin-type oxidized LDL receptor 1 (LOX-1) system in LF hypertrophy is unknown. We aimed to elucidate the potential involvement of oxidized LDL/LOX-1 system in ligamentum flavum (LF) hypertrophy.

METHODS

A total of 43 samples were collected from LF tissues of the patients who underwent posterior lumbar spinal surgery. Immunohistochemistry for LOX-1 was performed using human LF samples. We treated the cells in vitro with inflammatory cytokines TNF-α and IL-1β, oxidized LDL, and simvastatin. The expressions of LOX-1 and LF hypertrophy markers including type I collagen, Type III collagen, and COX-2 were assessed by real-time RT-PCR and immunocytochemistry. Phosphorylation of MAPKs and NF-κb was evaluated by Western blot after treatment with TNF-α, IL-1β, oxidized LDL, and simvastatin.

RESULTS

A significant weak correlation was observed between the number of positive cells of LOX-1 and cross-sectional area of LF on preoperative axial magnetic resonance imaging. In functional analysis, simvastatin treatment neutralized the oxidized LDL-mediated induction of mRNA expressions of LF hypertrophy markers. Western blot analysis showed that oxidized LDL as well as TNF-α and IL-1β activated the signaling of MAPKs and NF-κb in LF cells, and that simvastatin treatment reduced the phosphorylation of all signaling. The TNF-α and IL-1β treatments increased both mRNA and protein expression of LOX-1 in LF cells.

CONCLUSION

We found a link between the oxidized LDL/LOX-1 system and LF hypertrophy. In addition, our in vitro analysis indicate that oxidized LDL may affect LF hypertrophy through signaling of MAPKs. Our results suggest that the oxidized LDL/LOX-1 system may be a potential therapeutic target for LSS.

A Simple Scale for Screening Lower-Extremity Arterial Disease as a Possible Cause of Low Back Pain: a Cross-sectional Study Among 542 Subjects

BACKGROUND

Epidemiological, imaging, and anatomical studies suggest an association between proximal arterial atherosclerosis and development of low back pain (LBP).

OBJECTIVES

We aimed to define (1) the frequency and (2) factors associated with exercise-induced proximal ischemia (EIPI) in individuals with LBP and (3) develop a clinical screening scale.

DESIGN

Monocentric cross-sectional study.

PARTICIPANTS

All patients with history of ongoing LBP referred to our exercise investigation laboratory for exercise transcutaneous oximetry (ex-tcPO₂) between January 2011 and December 2017 (n = 542; mean age, 65.4 ± 10.9; 83.9% men).

MAIN MEASURES

EIPI was defined as a decrease from rest of oxygen pressure (DROP) below - 15 mmHg on the lumbar and/or buttock probes. Ex-tcPO₂ is a reliable validated tool for diagnosing EIPI in comparison with arteriography and computed tomography angiography. Ex-tcPO₂ was performed on a treadmill until symptom manifestation or exhaustion. Clinical data were collected using interview questionnaires, medical file review, and clinical examination.

KEY RESULTS

EIPI was diagnosed in 282 patients (52%). Age ≤ 70 years (OR, 2.22; 95% CI, 1.35-3.57; p = 0.002), a history of proximal revascularization (OR, 2.64; 95% CI, 1.50-4.65; p = 0.001), use of antiplatelet medication (OR, 1.71; 95% CI, 0.96-3.06; p = 0.069), a relationship between exercise and LBP (OR, 2.61; 95% CI, 1.49-4.57; p = 0.001), and an abnormal ankle to brachial index (OR, 2.87; 95% CI, 1.77-4.66; p < 0.0001) were identified as EIPI predictors. Using these items, we developed a screening scale that showed an area under the receiver operating characteristics curve of .756. At a score of ≥ 3, the sensitivity, specificity, and accuracy for EIPI were 84%, 55%, and 71%, respectively.

CONCLUSIONS

EIPI was common among our patients with LBP undergoing ex-TcPO₂. Our screening scale could help better select the patients who require angiography.

[Back pain and intervertebral disc degeneration in the International Classification of Diseases 11th revision]

In 2018, the World Health Organization introduced a new version of the International Classification of Diseases (ICD-11), which is preliminary and introductory in nature and will come into force on 1 January 2022. One of the most changed sections compared to ICD-10 is the section characterizing the spine pain syndrome and other manifestations of discogenic pathology. The article describes the terms and codes for the degenerative lesion of the intervertebral disk (IVD) in accordance with the requirements of ICD-11, which also agree with the definitions of the 2nd revision of the nomenclature and classification of the pathology of the lumbar IVD from 2014. The basic concepts of IVD degenerative changes are also revealed. The need to create a new revision of the domestic clinical classification of vertebrogenic neurologic pathology adapted to ICD-11 codes is underlined.