Identification of Epigenetic Biomarkers of Adolescent Idiopathic Scoliosis Progression: A Workflow to Assess Local Gene Expression.

Adolescent idiopathic scoliosis (AIS) is a three-dimensional structural deformity of the spine that affects 2-3% of adolescents under the age of 16. AIS etiopathogenesis is not completely understood; however, the disease phenotype is correlated to multiple genetic loci and results from genetic-environmental interactions. One of the primary, still unresolved issues is the implementation of reliable diagnostic and prognostic markers. For clinical management improvement, predictors of curve progression are particularly needed. Recently, an epigenetic contribution to AIS development and progression was proposed; nevertheless, validation of data obtained in peripheral tissues and identification of the specific mechanisms and genes under epigenetic control remain limited. In this study, we propose a methodological approach for the identification of epigenetic markers of AIS progression through an original workflow based on the preliminary characterization of local expression of candidate genes in tissues directly involved in the pathology. The feasibility of the proposed methodological protocol has been originally tested here in terms of identification of the putative epigenetic markers of AIS progression, collection of the different tissues, retrieval of an appropriate amount and quality of RNA and DNA, and identification of suitable reference genes.

The relationship between spinal alignment and activity of paravertebral muscle during gait in patients with adult spinal deformity: a retrospective study.

BACKGROUND: Spinal alignment in patients with adult spinal deformity (ASD) changes between rest and during gait. However, it remains unclear at which point the compensated walking posture breaks down and how muscles respond. This study used time-synchronized electromyography (EMG) to investigate the relationship between dynamic spinal alignment and muscle activity during maximum walking duration to reveal compensation mechanisms. METHODS: This study collected preoperative three-dimensional gait analysis data from patients who were candidates for corrective surgery for ASD from April 2015 to May 2019. We preoperatively obtained dynamic spinal alignment parameters from initiation to cessation of gait using a motion capture system with time-synchronized surface integrated EMG (iEMG). We compared chronological changes in dynamic spinal alignment parameters and iEMG values 1) immediately after gait initiation (first trial), 2) half of the distance walked (half trial), and 3) immediately before cessation (last trial). RESULTS: This study included 26 patients (22 women, four men) with ASD. Spinal sagittal vertical axis distance during gait (SpSVA) increased over time (first vs. half vs. last, 172.4 ± 74.8 mm vs. 179.9 ± 76.8 mm vs. 201.6 ± 83.1 mm; P < 0.001). Cervical paravertebral muscle (PVM) and gluteus maximus activity significantly increased (P < 0.01), but thoracic and lumbar PVM activity did not change. Dynamic spinal alignment showed significant correlation with all muscle activity (cervical PVM, r = 0.41-0.54; thoracic PVM, r = 0.49-0.66; gluteus maximus, r = 0.54-0.69; quadriceps, r = 0.46-0.55) except lumbar PVM activity. CONCLUSION: Spinal balance exacerbation occurred continuously in patients with ASD over maximum walking distance and not at specific points. To maintain horizontal gaze, cervical PVM and gluteus maximus were activated to compensate for a dynamic spinal alignment change. All muscle activities, except lumbar PVM, increased to compensate for the spinal malalignment over time.

Clinical Efficacy and Imaging Observation of Three Surgical Approaches in Treatment of Thoracolumbar Fractures.

Objective: To observe the efficacy and imaging of surgical treatment of thoracolumbar fractures via the paravertebral muscle space approach. Methods: A retrospective analysis was conducted on patients with thoracolumbar fractures receiving surgery in Baoding First Central Hospital from January 2019 to December 2020. According to different surgical approaches, they were divided into paravertebral approach group, posterior median approach group and minimally invasive percutaneous approach group. They received surgery via the paravertebral muscle space approach, posterior median approach and minimally invasive percutaneous approach, respectively. Results: Statistically significant differences were found in surgical duration, intraoperative bleeding volume, intraoperative fluoroscopy frequency, postoperative drainage volume and hospital stay among the three groups. One year after surgery, the VAS, ADL and JOA scores of the paravertebral approach group and the minimally invasive percutaneous approach group had statistically significant differences from the posterior median approach group (P < 0.05). Conclusion: For the surgical treatment of thoracolumbar fractures, the clinical efficacy of the paravertebral muscle space approach is superior to that of the traditional posterior median approach, and the clinical efficacy of the minimally invasive percutaneous approach is similar to that of the posterior median approach. All the three approaches can effectively improve the postoperative function and pain symptoms of patients without increasing the incidence of complications. Compared with the posterior median approach, the surgery via the paravertebral muscle space and minimally invasive percutaneous approaches presents shorter surgical duration, less bleeding and shorter hospital stay, which is more conducive to postoperative recovery of patients.

Cohort study on the relationship between morphologic parameters of paravertebral muscles, BMI and lumbar lordosis on the severity of lumbar stenosis.

INTRODUCTION: There is a growing body of literature separately linking lumbar spinal stenosis (LSS) with various factors such as paravertebral muscle (PVM) impaired function/morphology, lordosis or BMI. However, their interplay is yet to be known. The present study aims to investigate the relationship between PVM morphology, BMI and lumbar lordosis in a population with a surgical indication for LSS. MATERIALS AND METHODS: A cross-sectional retrospective study was conducted on a group of 122 patients diagnosed with LSS in a hospital setting and scheduled for spine surgery. Epidemiological data and body mass index (BMI) were gathered. The cross-sectional area of the psoas muscle (rCSA) at the L4-L5 disc level on preoperative axial T2 MRI was measured. Fat infiltration of the anterior (APVM) and posterior paravertebral muscles (PPVM) was evaluated according to Goutallier classification while the severity of lumbar stenosis was staged according to Schizas criteria. Lumbar lordosis was measured on sagittal MRI using Cobb's angle method. The presence of the "rising psoas" sign was also noted. Statistical analysis of the data was performed using Pearson and Spearman correlations. RESULTS: Statistical analysis revealed a moderate correlation between the severity of LSS and BMI (p = 0.001), and fatty infiltration of paravertebral muscles (p = 0.000, p = 0.000). Adjusting for age, gender, and BMI resulted in a low correlation (p = 0.003, p = 0.045), rCSA correlated negatively with age, gender, and lordosis. BMI had a low positive correlation with lumbar lordosis (p = 0.006), severity (p = 0.001), number of levels (p = 0.005) and PPVM (p = 0.031). CONCLUSIONS: This study highlighted the relationship between PVM morphology and the severity of radiological signs in patients with LSS undergoing spine surgery and found a correlation independent of age, gender, and BMI. BMI was also shown to correlate with the severity after controlling for age and gender. rCSA has limited use in evaluating the severity of LSS.

Computed tomography-based paravertebral muscle density predicts subsequent vertebral fracture risks independently of bone mineral density in postmenopausal women following percutaneous vertebral augmentation.

BACKGROUND: The risk of subsequent vertebral fractures (SVF) after the primary vertebral fracture cannot be explained by lower bone mineral density (BMD) alone. Computed tomography (CT) measurements of paravertebral muscle density (PMD) are recognized radiographic markers used to predict physical function, fragile fractures. AIMS: This study aims to investigate the relationship between PMD and the risk of SVF in cohorts of postmenopausal women, and to determine if combining both PMD and BMD measures derived from CT can improve the accuracy of predicting SVF. METHODS: This study enrolled 305 postmenopausal women between the ages of 50 and 88 for 3 years of follow-up studies. Trabecular attenuation (Hounsfield units, HU) was measured at L1 level and muscle attenuation of paravertebral muscle at L3 level on preoperative lumbar CT scans to determine the L1 BMD and L3 PMD. Kaplan-Meier analysis was applied to evaluate SVF-free survival. The hazard ratios (HRs) of PMD for SVF events were estimated with the Cox proportional hazards model. The predictive values of L1 BMD and L3 PMD for SVF were quantified using the Receiver-Operating Characteristic (ROC) curve. RESULT: During the 3 years of follow-up studies, 88 patients (28.9%) suffered an SVF. ROC curve analysis demonstrated that an L3 PMD threshold of 32 HU had a sensitivity of 89.8% and a specificity of 62% for the prediction of SVF. Kaplan-Meier analysis showed that L3 PMD ≤ 32 HU was significantly associated with lower SVF-free survival (p < 0.001; log-rank test). After adjusting for age, BMI, diabetes, postoperative osteoporosis treatment, handgrip strength, L1 BMD, multivariate analyses also indicated a persistent modest effect of L3 PMD on SVF-free survival. The area under the ROC curve of L3 PMD and L1 BMD, combined to predict the risk of SVF, was 0.790, which was significantly higher than the value for L1 BMD alone (0.735). L3 PMD and L1 BMD significantly improved the accuracy of SVF risk prediction compared with L1 BMD alone, which was confirmed by reclassification improvement measures. The inclusion of handgrip strength and postoperative osteoporosis treatment in the model further improved SVF prediction accuracy, and PMD remained significant in the model. CONCLUSION: Decreased L3 PMD is an independent risk predictor of SVF. Combined CT-based L1 BMD and L3 PMD can significantly improve the accuracy of predicting the risk of SVF in postmenopausal women who have suffered prior osteoporotic vertebral fractures.

Paravertebral Muscles as Indexes of Sarcopenia and Sarcopenic Obesity: Comparison With Imaging and Muscle Function Indexes and Impact on Cardiovascular and Metabolic Disorders.

OBJECTIVE. The objectives of this study were to propose the use of the cross-sectional area of paravertebral muscle (PMA) and the ratio of the PMA to the cross-sectional area of visceral fat (PVR) as new indexes of sarcopenia or sarcopenic obesity through comparison with existing indexes and to show the clinical associations of PMA and PVR with hypertension and diabetes. SUBJECTS AND METHODS. A total of 1270 participants (608 men and 662 women; mean [± SD] age, 63.57 ± 6.94 years) were recruited from a community-based population of elderly individuals. PMA and PVR were measured on single-slice abdominal CT images. Pearson correlation was used to evaluate the correlation of PMA and PVR with widely used imaging and muscle function indexes of sarcopenia and sarcopenic obesity. Tertile categories of PMA and PVR were evaluated to investigate associations with risks for hypertension and diabetes in men and women, by use of separate multivariable logistic regression models. RESULTS. PMA was correlated with the cross-sectional area of thigh muscle on CT, appendicular skeletal muscle mass (ASM) on dual-energy x-ray absorptiometry, height-adjusted ASM (calculated as ASM divided by the height in meters squared), and body mass index (BMI)-adjusted ASM (calculated as ASM divided by BMI) (p < .01). PMA was also correlated with hand grip strength and gait speeds (p < .01). PVR was correlated with height-adjusted ASM and BMI-adjusted ASM (p < .01). A high PVR significantly decreased the odds ratios for hypertension and diabetes in the unadjusted model and the model adjusted for age, smoking, and drinking status. The ratio of the cross-sectional area of thigh muscle to the cross-sectional area of visceral fat and the BMI-adjusted ASM produced results similar to those of PVR in terms of the odds ratios for hypertension and diabetes. CONCLUSION. Single-slice abdominal CT can supply PMA and visceral fat information together. PMA and PVR were found to be reliable indexes of sarcopenia and sarcopenic obesity. A high PVR was associated with low risks for hypertension and diabetes.

Spontaneous infarction of lumbar roots, vertebrae and paravertebral muscles.

Ischemic injury to the lumbosacral nerve roots and plexus is a rare condition resulting from thrombosis of one or several lumbar arteries. As the arterial supply of the spine presents great variations between subjects, the clinical presentation of lumbar thrombosis is highly variable depending on the relative involvement of nerve roots, bones or muscles. Diagnosis can be challenging, especially in the acute phase, as different structures can be simultaneously involved. The identification of an enlarged vessel centered in the area of tissue damage can help with the final diagnosis. We present the case of a 59-year-old woman who presented with spontaneous incomplete cauda equina syndrome due to diffuse lumbar nerve root infarction. On imaging, acute lumbar artery thrombosis was confirmed, and in addition to nerve roots, adjacent vertebral and paraspinal muscle infarctions were also present.

An assessment of morphological and pathological changes in paravertebral muscle degeneration using imaging and histological analysis: a cross-sectional study.

BACKGROUND: The high signal of paravertebral muscle (PVM) on T2-weighted image (T2WI) is usually considered to be fatty degeneration. However, it is difficult to distinguish inflammatory edema from fatty degeneration on T2WI. The purpose of this study was to identify different types of PVM high signal in patients with low back pain (LBP) through magnetic resonance imaging (MRI) and histology. METHODS: Seventy patients with LBP underwent MRI. The signal change of multifidus both on T2WI and fat suppression image (FSI) was quantified by Image J. Furthermore, 25 of the 70 patients underwent surgery for degenerative lumbar disease and their multifidus were obtained during the operation. Histological analysis of the samples was performed by HE staining. RESULT: Three types of PVM signal changes were identified from the MRI. Type 1 (n = 36) indicated fatty degeneration characterized by a high signal on T2WI and low signal on FSI. High signal on both T2WI and FSI, signifying type 2 meant inflammatory edema (n = 9). Type 3 (n = 25) showed high signal on T2WI and partial signal suppression on FSI, which meant a combination of fatty degeneration and inflammatory edema. Histological results were consistent with MRI. Among the 25 patients who underwent surgery, type 1 (n = 14) showed adipocytes infiltration, type 2 (n = 3) showed inflammatory cells infiltration and type 3 (n = 8) showed adipocytes and inflammatory cells infiltration. CONCLUSION: From our results, there are three types of pathological changes in patients with PVM degeneration, which may help to decide on targeted treatments for LBP.

The natural course of the paravertebral muscles after the onset of osteoporotic vertebral fracture.

This study revealed the change in the paravertebral muscles in patients with osteoporotic vertebral fracture. Increased pain is likely to be the driver for reduced activity, reduced activities of daily living, and consequent increase in fat infiltration of the paravertebral muscles, assumed to be secondary to reduced activity level or, conversely, partial immobilization. INTRODUCTION: To reveal the time courses and impact of the paravertebral muscles (PVMs) on the healing process of osteoporotic vertebral fractures and risk factors for PVM decrease. METHODS: Consecutive patients with symptomatic osteoporotic vertebral fractures were enrolled in 11 hospitals. At enrollment and 3- and 6-month follow-up, PVMs, including the multifidus and erector spinae, were examined using magnetic resonance imaging (MRI). The PVM cross-sectional area (CSA) and fat signal fraction (FSF) were measured at L3. Low back pain (LBP), activities of daily living (ADLs), and risk factors for PVM decrease at the 6-month follow-up were investigated. PVM decrease was defined as > 1 standard deviation decrease of the CSA or > 1 standard deviation increase of the FSF. RESULTS: Among 153 patients who completed the 6-month follow-up, 117 (92 women, 79%) had MRI of L3 at enrollment and 3- and 6-month follow-up (mean age at enrollment, 78.5 years). The CSA did not change 6 months from onset (p for trend = 0.634), whereas the FSF significantly increased (p for trend = 0.033). PVM decrease was observed in 30 patients (26%). LBP was more severe, and delayed union was more frequent in patients with PVM decrease (p = 0.021 mixed-effect model and p = 0.029 chi-square test, respectively). The risk factors for PVM decrease were ADL decline at the 3-month follow-up (adjusted odds ratio = 5.35, p = 0.026). CONCLUSION: PVM decrease was significantly related to LBP and delayed union after osteoporotic vertebral fracture onset. ADL decline at the 3-month follow-up was a risk factor for PVM decrease. Therefore, restoring ADLs within 3 months after onset is important.

Low paravertebral muscle mass in patients with bone metastases from lung cancer is associated with poor prognosis.

PURPOSE: Low skeletal muscle mass has been associated with poor prognosis in patients with advanced lung cancer. However, little is known about the relationship between skeletal muscle mass and overall survival in patients with bone metastases from lung cancer. The objective of the present study was to evaluate the prognostic value of low trunk muscle mass in predicting overall survival in these patients. METHODS: The data from 198 patients who were diagnosed with bone metastases from lung cancer from April 2009 to May 2017 were retrospectively reviewed. The areas of the psoas and paravertebral muscles were measured at the level of the third lumbar vertebra on computed tomography scans taken at the time nearest to the diagnosis of bone metastasis. Muscle area was evaluated for male and female cohorts separately using different cutoff points. Cox proportional hazards analysis was performed to evaluate the factors independently associated with overall survival. RESULTS: The overall survival of patients in the lowest quartile for psoas muscle area or paravertebral muscle area was significantly shorter than that of patients above the 25th percentile for muscle area (p < 0.001). Multivariate analyses showed that paravertebral muscle mass (hazard ratio, 1.73; 95% confidence interval, 1.17-2.56; p = 0.006), epidermal growth factor receptor-targeted therapy, and performance status were independent prognostic factors. CONCLUSIONS: Low paravertebral muscle mass was associated with shorter survival, independently of known prognostic factors.

Abnormal paravertebral muscles development is associated with abnormal expression of PAX3 in adolescent idiopathic scoliosis.

PURPOSE: The study is aimed to investigate the expression of PAX3 in bilateral paravertebral muscles in adolescent idiopathic scoliosis (AIS) and controls, and to further clarify its association with the paravertebral muscle volume and curve severity. METHODS: Ten AIS patients and 10 age-matched controls with lumbar disc herniation were included. Bilateral biopsies of paravertebral muscles were obtained at the apical vertebral level for patients and at L5 level for controls. The concave and convex expression of PAX3 was compared between the two groups. The AIS patients were evaluated with magnetic resonance imaging scan of the spine at the apex. The muscle volume of apical paravertebral muscles were measured and compared between concave and convex side. Correlation between concave/convex PAX3 expression ratio and concave/convex muscle volume ratio was analyzed. RESULTS: AIS patients were found to have significantly lower PAX3 expression than controls (p < 0.001). Moreover, PAX3 expression on the concave side was lower than that on the convex side in AIS (p = 0.003). The muscle volume on the concave side was smaller than convex side as well (p = 0.001). The PAX3 expression ratio was significantly correlated with the muscle volume ratio (r = 0.745, p = 0.013); however, there was no significant correlation between PAX3 expression ratio and Cobb angle (r = 0.284, p = 0.427). CONCLUSION: The PAX3 muscle expression and paravertebral muscle volume were asymmetric in AIS patients, and the expression ratio was positively related with the muscle volume ratio. These findings suggested PAX3 might have functional role in the development of AIS via regulating development of paravertebral muscle. These slides can be retrieved under Electronic Supplementary Material.

Abnormal change of paravertebral muscle in adult degenerative scoliosis and its association with bony structural parameters.

PURPOSE: While many studies have explored the association between paravertebral muscle (PVM) change and low back pain/lumbar spinal stenosis, little is known about PVM change in adult degenerative scoliosis (ADS). The present study explored the PVM change in ADS and investigated its association with bony structural parameters. METHODS: We evaluated 78 patients in ADS without radiculopathy (ADS group) and 65 healthy persons without degenerative lumbar diseases (control group). Percentage of fat infiltration area (%FIA) of multifidus muscle at L1 to S1 disk level was measured by MRI, using ImageJ software. Lumbar scoliosis Cobb's angle, lumbar lordotic angle, lateral vertebral translation, and apical vertebral rotation were recorded in ADS group, and relationship between PVM change and these factors was analyzed. RESULTS: In the control group, the mean %FIA of multifidus muscle was not significantly different between the bilateral sides at all levels (P > 0.05). In the ADS group, the mean %FIA was significantly higher on the concave side than the convex side at all levels (P < 0.05). Asymmetric degree of multifidus muscle change was 8.55% ± 4.91%, which was positively correlated with lumbar scoliosis Cobb's angle, lateral vertebral translation, and apical vertebral rotation (0 < r < 1, P < 0.05), but negatively weak-correlated with lumbar lordotic angle (- 1 < r < 0, P < 0.05). CONCLUSIONS: Asymmetric PVM change in ADS is more often seen on the concave side, which is positive to evaluate the progression of scoliosis. Its asymmetric degree increases with progression of lumbar scoliosis Cobb's angle and decreased lumbar lordotic angle. Apical vertebral rotation and lateral vertebral translation can aggravate the asymmetric degree.

[Design of Paravertebral Muscle Monitoring System Based on Surface Electromyography].

In order to diagnose and evaluate the human spinal lesions through the paravertebral muscles, a paravertebral muscle monitoring system based on surface EMG signals was designed. The system used surface mount electrodes to obtain the surface myoelectric signal (sEMG) of paravertebral muscle. The signal was filtered and amplified by the conditioning circuit. The signal was collected by the microcontroller NRF52832 and was sent to the mobile APP. After the signal was preprocessed by the wavelet threshold denoising algorithm in APP, the time and frequency characteristics of the sEMG signal reflecting the functional state of the muscle were extracted. The calculated characteristic parameters was displayed in real time in the application interface. The experimental results show that the system meets the design requirements in analog signal acquisition, digital processing of signals and calculation of characteristic parameters. The system has certain application value.

Asymmetric expression of H19 and ADIPOQ in concave/convex paravertebral muscles is associated with severe adolescent idiopathic scoliosis.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is the most common paediatric spinal deformity. The etiology and pathology of AIS remain unexplained, and have been reported to involve a combination of genetic and epigenetic factors. Since paravertebral muscle imbalance plays an important role in the onset and progression of scoliosis, we aimed to investigate transcriptomic differences by RNA-seq and identify significantly differentially expressed transcripts in two sides of paravertebral muscle in AIS. METHODS: RNA-seq was performed on 5 pairs of paravertebral muscle from 5 AIS patients. Significantly differentially expressed transcripts were validated by quantitative reverse polymerase chain reaction. Gene expression difference was correlated to clinical characteristics. RESULTS: We demonstrated that ADIPOQ mRNA and H19 is significantly differentially expressed between two sides of paravertebral muscle, relatively specific in the context of AIS. Relatively low H19 and high ADIPOQ mRNA expression levels in concave-sided muscle are associated with larger spinal curve and earlier age at initiation. We identified miR-675-5p encoded by H19 as a mechanistic regulator of ADIPOQ expression in AIS. We demonstrated that significantly reduced CCCTC-binding factor (CCTF) occupancy in the imprinting control region (ICR) of the H19 gene in the concave-sided muscle contributes to down-regulated H19 expression. CONCLUSIONS: RNA-seq revealed transcriptomic differences between two sides of paravertebral muscle in AIS patients. Our findings imply that transcriptomic differences caused by epigenetic factors in affected individuals may account for the structural and functional imbalance of paravertebral muscle, which can expand our etiologic understanding of this disease.

Pectoralis muscle area and mortality in smokers without airflow obstruction.

BACKGROUND: Low muscle mass is associated with increased mortality in the general population but its prognostic value in at-risk smokers, those without expiratory airflow obstruction, is unknown. We aimed to test the hypothesis that reduced muscle mass is associated with increased mortality in at-risk smokers. METHODS: Measures of both pectoralis and paravertebral erector spinae muscle cross-sectional area (PMA and PVMA, respectively) as well as emphysema on chest computed tomography (CT) scans were performed in 3705 current and former at-risk smokers (≥10 pack-years) aged 45-80 years enrolled into the COPDGene Study between 2008 and 2013. Vital status was ascertained through death certificate. The association between low muscle mass and mortality was assessed using Cox regression analysis. RESULTS: During a median of 6.5 years of follow-up, 212 (5.7%) at-risk smokers died. At-risk smokers in the lowest (vs. highest) sex-specific quartile of PMA but not PVMA had 84% higher risk of death in adjusted models for demographics, smoking, dyspnea, comorbidities, exercise capacity, lung function, emphysema on CT, and coronary artery calcium content (hazard ratio [HR] 1.85 95% Confidence interval [1.14-3.00] P = 0.01). Results were consistent when the PMA index (PMA/height2) was used instead of quartiles. The association between PMA and death was modified by smoking status (P = 0.04). Current smokers had a significantly increased risk of death (lowest vs. highest PMA quartile, HR 2.25 [1.25-4.03] P = 0.007) while former smokers did not. CONCLUSIONS: Low muscle mass as measured on chest CT scans is associated with increased mortality in current smokers without airflow obstruction. TRIAL REGISTRATION: NCT00608764.

Evaluation of paravertebral muscle atrophy and fatty degeneration in ankylosing spondylitis.

AIM: The purpose of this study was to assess morphological changes in the paravertebral muscles in patients with ankylosing spondylitis. MATERIALS AND METHODS: Fifty-one patients diagnosed with ankylosing spondylitis and a 50 member control group were included in the study. The surface area of the multifidus and erector spinae muscles was measured at four levels between L1 and L5, and fatty degeneration in these muscles was scored. Lumbosacral and lumbar lordotic angles were determined for the patient and control groups. RESULTS: Loss of muscle cross-sectional area compatible with atrophy was present at all four levels in the paraspinal muscles in patients with ankylosing spondylitis. A negative correlation was observed between paravertebral muscle area and duration of disease at three levels, but not at L1-2. Although muscle area decreased with the duration of disease at the L1-2 level, this was not statistically significant (r= -0.195, p = 0.171). Comparison of intramuscular fatty degeneration between the groups revealed increased intramuscular fat at all levels in patients with ankylosing spondylitis, with the exception of L3-4, and a positive correlation between fatty degeneration and duration of disease was determined at all levels. CONCLUSION: Chronic inflammation, cytokine-mediated fibrosis, immobilization, and postural changes in ankylosing spondylitis contribute to fatty degeneration and atrophy in the paravertebral muscles.

Reliability of quantifying the spatial distribution of fatty infiltration in lumbar paravertebral muscles using a new segmentation method for T1-weighted MRI.

BACKGROUND: To our knowledge, there are no methods allowing for quantification of the spatial distribution of lumbar paravertebral muscle fatty infiltration (FI) in the transverse plane. There is an increasing emphasis on muscle tissues as modifiable factors in lumbar spine health. Population datasets based on conventional T1-weighted (T1-W) magnetic resonance imaging (MRI) represent a valuable resource for examining all spinal tissues, and methods with reliability are needed. The aim of our study was to determine the reliability of a novel method quantifying lumbar paravertebral muscle fat content based on conventional T1-W MRI. METHODS: Axial 3-Tesla T1W MRIs from ten adult subjects (3W, 7M; mean age 52.8 ± SD 7.2 years) were randomly selected from the large prospective cross-sectional Hong Kong Population-based Disc Degeneration Cohort study examining lumbar spine degeneration. The selected sample included subjects with mixed imaging-determined disc degeneration and low back pain history. Two raters with MRI lumbar paravertebral muscle analysis experience (R1 > 250 h and R2 > 1000 h) repeat-measured the image-set a week apart. Multifidus and erector spinae (spinalis, longissimus and iliocostalis) were manually outlined together on a single-slice from the inferior vertebral end-plates of L1 to L5 using a semi-automated, quartile-defining (Q1-4 (medial to lateral) and Qmean) MatLab-based programme. Bland-Altman plots and intra-class correlation coefficients (ICC) with 95 % confidence intervals (CI) describe intra- and inter-rater reliability according to lumbar level, quartile, and side, and combined level and quartile. RESULTS: There was good intra- (ICC = 0.88; CI: 0.87-0.90) and inter-rater agreement (ICC = 0.82; CI: 0.80-0.84). Intra-rater values for Qmean (ICC; CI) were higher at L5 (0.89; 0.79-0.94) than L1 (0.61; 0.37-0.78). Higher intra-rater values for L1-5 were shown at Q1 (0.93; 0.91-0.95) than Q3 (0.83; 0.78-0.87) or Q4 (0.81; 0.76-0.85), and on the right (0.91; 0.90-0.93) than left (0.85; 0.83-0.88). Similar observations were made for inter-rater values in terms of lumbar level and quartile, with no differences between sides shown. CONCLUSIONS: In our study of ten cases we demonstrate a reliable method to quantify the spatial distribution of fat content in lumbar paravertebral muscles based on T1W MRI. Understanding the geography of fat content in these muscles may offer additional insight in determining and improving spinal health. The clinical relevance and application of this method require testing across various populations to build on the early feasibility established in this study.

Relationship between paravertebral muscle function, pelvic incidence, and health-related quality of life in patients with degenerative spinal deformity.

BACKGROUND: Patients with degenerative spinal deformity often experience symptoms that seriously affect their quality of life, such as low back pain and dysfunction. This study aimed to investigate the relationship between paravertebral muscle function and pelvic incidence (PI) and their effect on health-related quality of life (HRQL) in patients with degenerative spinal deformity. METHODS: A total of 112 patients with degenerative spinal deformity in Southwest Hospital (Chongqing, China) were enrolled. They were divided into groups according to PI angle: high (PI > 60°, n = 37), normal (PI 50°-60°, n = 31), and low (PI < 50°, n = 44). Paravertebral muscle strength and endurance were assessed using the prone external fixation test frame. The sagittal vertical axis (SVA) was measured on X-rays of the spine in an anterolateral position, and all subjects were assessed with the Oswestry Disability Index (ODI), Roland-Morris questionnaire (RMQ), and 36-Item Short Form Health Survey (SF-36). Pearson or Spearman coefficients were used to assess the relationship of paravertebral muscle function with SVA, PI, and health-related quality of life. RESULTS: Maximal voluntary exercise (MVE) in the high-PI group was significantly lower than the MVE of both the normal- and low-PI groups (p < 0.05). There was no significant difference in MVE between the normal- and low-PI groups (p > 0.05). There was no significant difference in endurance time, SVA, ODI, RMQ, and SF-36 among the three groups. Paravertebral muscle MVE was negatively correlated with PI, SVA, ODI, and RMQ (r = - 0.193, - 0.210, - 0.283, - 0.277, p < 0.05). Endurance time of paravertebral muscle was also negatively correlated with SVA, ODI, and RMQ (r = - 0.200, - 0.420, - 0.348, p < 0.05) and positively correlated with SF-36 (r = 0.245, p < 0.05). In addition, paravertebral muscle MVE was positively correlated with the physical functioning score of the SF-36 (r = 0.251, p < 0.05), and the endurance time of paravertebral muscle was positively correlated with the physical functioning, physical role, bodily pain, and social function scores of the SF-36 (r = 0.342, 0.230, 0.209, 0.256, p < 0.05). CONCLUSIONS: High PI may serve as a risk factor for decreased paraspinal muscle strength in patients with degenerative spinal deformities. Early and targeted exercises focusing on paraspinal muscle strength and endurance could potentially be of positive significance in slowing down the progression of sagittal imbalance, alleviating functional disorders, and increasing health-related quality of life in patients with degenerative spinal deformity.

Decreased grip strength is associated with paraspinal muscular oxidative stress in female lumbar degenerative disease patients.

We aimed to investigate the relationship between superoxide dismutase 2-related oxidative stress in the paraspinal muscles and spinal alignment, clinical skeletal muscle parameters, and mitochondrial function. Multifidus muscle samples from patients who underwent posterior lumbar surgery were analyzed. Patients with diseases affecting oxidative stress and spinal alignment were excluded. The superoxide dismutase 2 redox index was defined as the ratio of reactive oxygen species (superoxide) to antioxidant enzymes (superoxide dismutase 2) and was used as an index of oxidative stress. Patients were divided into two groups based on the superoxide dismutase 2 redox index. Spinal alignment, clinical skeletal muscle parameters, and succinic dehydrogenase (SDH) mean grayscale value were compared between the groups, with analyzes for both sexes. Multiple regression analyzes were used to adjust for the confounding effect of age on variables showing a significant difference between the two groups. Thirty-five patients with lumbar degenerative diseases were included. No significant differences were observed between the two groups for any of the parameters in males; however, females with a higher superoxide dismutase 2 redox index had greater lumbar lordosis, lower grip strength, and higher SDH mean grayscale value than those with a lower index. Multiple regression analyzes revealed that the superoxide dismutase 2 redox index was an independent explanatory variable for lumbar lordosis, grip strength, and SDH mean grayscale value in female patients. In conclusion, superoxide dismutase 2-related oxidative stress in the paraspinal muscles was associated with mitochondrial dysfunction and decreased grip strength in female lumbar degenerative disease patients.

Evaluation of Paravertebral Muscle Structure Asymmetry in Idiopathic Scoliosis Using Imaging Techniques.

OBJECTIVE: This study aimed to assess variances in paravertebral muscle structure in individuals with idiopathic scoliosis (IS) through imaging techniques. METHODS: A cohort of 112 patients diagnosed with IS and treated at our institution between January and December 2023 was included in the analysis. During the same period, 37 patients with secondary scoliosis (SS) were included as controls. Imaging data were used to measure the Cobb angle of the apical vertebrae in scoliosis patients, along with the area and fat infiltration of the paravertebral muscles on both sides. Finally, the cross-sectional area of the paravertebral muscles and the degree of fat infiltration were comparatively evaluated. RESULTS: In patients with IS, the paravertebral muscles on the concave side of the main curve were significantly larger than those on the convex side (P < 0.05). The concave/convex muscle area ratio in IS patients showed a positive correlation with the Cobb angle and scoliosis duration (both P < 0.05). There was no significant difference in the muscle area ratio between patients with IS and those with SS (P > 0.05). In IS, the paravertebral muscles on the concave side of the main curve exhibited more fat infiltration than those on the convex side, with this fat infiltration positively correlating with body mass index, Cobb angle, age, and scoliosis duration. Similarly, the degree of fat infiltration in the paravertebral muscles on the concave side of SS was more than that observed on the convex side. Furthermore, the degree of fat infiltration in the paravertebral muscles associated with SS was more pronounced compared to that seen in IS (P < 0.05). CONCLUSIONS: In IS patients, the paravertebral muscles on the concave side are more prominent and exhibit more fat infiltration compared to those on the convex side. This fat infiltration positively correlates with the Cobb angle, scoliosis duration, body mass index, and age, possibly indicating scoliosis progression.