Volumetric and Fatty Infiltration Imbalance of Deep Paravertebral Muscles in Adolescent Idiopathic Scoliosis

Effects of botulinum toxin on paraspinal muscle imbalance during spinal motions in adolescents with idiopathic scoliosis: Assessment using high-density electromyography

BACKGROUND

The pathogenesis of adolescent idiopathic scoliosis (AIS) remains unclear, with muscle imbalance being a widely discussed hypothesis.

OBJECTIVE

This study examined the impact of muscle imbalance on AIS by injecting botulinum toxin A (BTX) into patients' unilateral muscles and investigating altered back muscle synergies.

METHODS

Three AIS patients received BTX injections in the concave-side paraspinal muscles. High-density electromyogram arrays placed from T8 to L4 recorded signals during five spinal motions at four timepoints (one pre-BTX and three post-BTX). Muscle synergies were extracted using non-negative matrix factorization and compared with data from ten healthy and ten AIS subjects from our previous studies.

RESULTS

Post-BTX, muscle activity maps during flexion/extension, sitting, and standing exhibited reduced symmetry, with concave/convex ratios decreasing and being statistically lower than those of healthy subjects at post-2 and post-3 follow-ups (p < 0.01). Muscles on the dominant side during lateral bending or axial rotation demonstrated decreased activation and differently distributed center of gravity positions on synergy maps compared to healthy subjects at all timepoints (p < 0.05). Post-BTX changes were particularly notable for the patient with mild deformity.

CONCLUSIONS

BTX affected the activation of paraspinal muscles, providing insights into the role of muscle imbalance in AIS and informing future therapeutic strategies.

Distinct clinical characteristics of adolescent idiopathic scoliosis with asymmetrical ESR1 expression in paraspinal muscle progenitor cells

Background

Previous studies found decreased ESR1 expression of concave paraspinal muscle progenitor cells could contribute to the initiation and progression of adolescent idiopathic scoliosis (AIS). The current study investigated the clinical characteristics of AIS with asymmetrical ESR1 expression in paraspinal muscle progenitor cells.

Materials and Methods

Bilateral deep paraspinal muscle progenitor cells were obtained from 25 consecutive eligible female patients with AIS. RT-qPCR was performed to evaluate the expression of ESR1. The demographic data (the age at surgery, height, weight, BMI, and age at initiation), posteroanterior and lateral radiographs data (Risser sign, Cobb angle, apical vertebral rotation, and location of apical vertebra), and MR imaging data (bilateral paraspinal muscle CSA ratio and bilateral fatty component ratio) were collected. The correlation between asymmetrical ESR1 expression of paraspinal muscle progenitor cells and the aforementioned clinical characteristics were analyzed.

Results

Twelve out of twenty-five patients (48%) showed bilateral ESR1 expression ratio (convex/concave) more than 1.5 folds, and they were divided into the ESR1 asymmetry group. When compared with the ESR1 symmetry group, patients in the ESR1 asymmetry group showed significantly more severe scoliosis (p = 0.041), more hypoplastic concave paraspinal muscle (p = 0.015), and more muscular fatty infiltration in the concave side (p = 0.034). The bilateral ESR1 expression ratio was significantly correlated with Cobb angle (r 2 = 0.282, p = 0.006), bilateral paraspinal muscle CSA ratio (r 2 = 0.253, p = 0.011), and bilateral fatty component ratio (r 2 = 0.248, p = 0.011).

Conclusion

There were 48% of AIS patients with significantly decreased ESR1 expression in concave paraspinal muscle progenitor cells (convex/concave>1.5 folds), while patients with more asymmetrical ESR1 expression showed more hypoplastic paraspinal muscle and fatty infiltration on the concave side, and more severe scoliotic deformity.

Characteristic of Paraspinal Muscle Change in Coronal Sub-type of Degenerative Lumbar Scoliosis and its Potential Clinical Significance

OBJECTIVE

Clarifying paraspinal muscle (PM) change in degenerative lumbar scoliosis (DLS) is positive to evaluate the progression of scoliosis. This research compares the characteristic of PM change among different coronal sub-types of DLS and explores its potential clinical significance.

METHODS

A total of 84 DLS patients between June 2019 to December 2021 were retrospectively analyzed. Patients were classified into three types based on the coronal balance distance (CBD): Type A, CBD <3 cm; Type B: C7 Plumb Line (C7PL) shifted to the concave side of the curve, and CBD >3 cm; Type C: C7PL shifted to the convex side of the curve, and CBD >3 cm. Fat infiltration rates in the multifidus (MS) and erector spinae (ES) at the apex of the main and fractional curves, and spinopelvic parameters were analyzed statistically. Pearson's or Spearman's correlation was applied to analyze the correlation between asymmetric degree of PM change and these parameters in three types.

RESULTS

There were 62 cases with coronal sub-Type A, 6 cases with Type B, and 16 cases with Type C. Patients in Type B and C demonstrated higher fat infiltration in MS on the concave side of both the main and fractional curves when compared to those in Type A. The asymmetric degree of ES change was positively correlated with CBD at the apex of the main curve in Type B and at the apex of the fractional curve in Type C respectively, and that of MS was positively correlated with apical vertebral rotation, while negatively strong-correlated with pelvic incidence and sacral slope in Type C.

CONCLUSION

PM fatty infiltration presented difference among varied coronal sub-types of DLS patients. The CBD in Type B and C patients was correlated with the asymmetric degree of ES change.

Quantitative analysis of paravertebral muscle asymmetry and its correlation with spinal deformity in patients with degenerative lumbar scoliosis: a retrospective case-control study

Background

The degeneration and functional decline of paravertebral muscles (PVMs) are reported to be closely linked to the incidence of degenerative lumbar scoliosis (DLS), a spinal deformity of the mature skeleton. However, the functional role and degeneration of PVMs and their relationship to the development of spinal deformities remain controversial. Therefore, the present study analyzed the morphological changes in the PVMs of patients with DLS, and explored the relationship between PVM degeneration and spinal osseous parameters.

Methods

In this retrospective case-control study, we evaluated the PVM parameters of patients with DLS (n=120) and compared them with patients free of DLS (control group, n=120). The cross-sectional area (CSA) and computed tomography (CT) values of the PVM at the lumbar vertebra 1-5 levels were measured. Further, the lumbar scoliosis Cobb, lumbar lordotic, and apical vertebral rotation angles were measured on CT and radiographs in the DLS group, and the relationship between PVM changes and these factors was analyzed.

Results

In the control group, the PVM CSA and CT values differed insignificantly between the bilateral sides at all levels (P>0.05). In the DLS group, the CSAs of the multifidus (MF) and erector spinae (ES) were larger on the convex side than the concave side (P>0.05), whereas that of the psoas major (PM) was smaller on the convex side than the concave side (P<0.05). The CT value of the PVM was lower on the convex side at all levels (P<0.05). The CSA and CT values on both sides of the patients were lower in the DLS group than the control group at all levels (P<0.05). Further, the degree of PVM asymmetry at the apical vertebral level was positively correlated with the lumbar scoliosis (P<0.01) and apical vertebral rotation angles (P<0.05), but negatively correlated with the lumbar lordotic angle (P<0.05).

Conclusions

Asymmetric degeneration of the PVM was observed bilaterally in DLS patients, and the degeneration was more pronounced on the concave side than the convex side. This asymmetrical degeneration was closely associated with the severity of lumbar scoliosis, vertebral rotation, and loss of lumbar lordosis, and a stronger correlation was observed with the MF and ES than with the PM.

Associations between paraspinal muscle characteristics and spinal curvature in conservatively treated adolescent idiopathic scoliosis: a systematic review

BACKGROUND CONTEXT

Children with adolescent idiopathic scoliosis (AIS) may show asymmetrical paraspinal muscle characteristics.

PURPOSE

To summarize the evidence regarding: (1) the associations between various paraspinal muscle characteristics and spinal curvature; (2) whether paraspinal muscle properties significantly differed between children with and without AIS; and (3) whether baseline paraspinal muscle characteristics predicted curve progression.

STUDY DESIGN/SETTING

Systematic literature review.

METHODS

Five databases (CINAHL, Academic Search Premier, MEDLINE, Scopus, and PubMed) were searched from inception to May 2022. This protocol was registered in the PROSPERO database of systematic reviews CRD 42020171263. The Critical appraisal skills program, the Appraisal Tool for Cross-Sectional Studies and Quality In Prognosis Studies tool were used to evaluate the risk of bias of the included studies. The strength of evidence of each identified association was determined by the Grading of Recommendations Assessment, Development, and Evaluation System (GRADE).

RESULTS

Of 1,530 identified citations, four cohort, 17 cross-sectional, and 23 case-control studies including 31 with low, nine with moderate and four with high risk of bias were included. Low to very low-strength evidence supported that the convex side of the curve had more type I muscle fibers, higher muscle volume and paraspinal muscle activity, while the concavity had more intramuscular fatty infiltration. Very low-strength evidence substantiated greater side-to-side surface electromyography signals during left trunk bending in prone lying, standing, and standing with perturbation between people with and without AIS. Also, low to very low-strength evidence supported that a larger side-to-side surface electromyography ratio at the lower end vertebra predicted curve progression.

CONCLUSIONS

Our review highlights that paraspinal muscles on the concavity of the curve demonstrate consistent changes (ie, altered muscle-related gene expression, muscle atrophy, increased fatty infiltration, reduced type I fibers, and reduced muscle activity), which may be the cause or consequence.

Comparison of elasticity changes in the paraspinal muscles of adolescent patients with scoliosis treated with surgery and bracing

Scoliosis is a three-dimensional spinal deformity, and paraspinal muscles play an important role as stabilizers of the spinal curve. In this prospective study, we compared elasticity changes in the paraspinal muscles of adolescent patients with scoliosis after surgery or bracing. Elasticity was measured on the concave and convex sides of the paraspinal muscles at the apex of the curve at the beginning of treatment and 6 and 12 months after treatment. Twenty-six patients with correction surgery (n = 15) or bracing (n = 11) were included. At initial evaluation, the Cobb angle was larger in the surgery group (72.3 ± 20.2° in surgery vs. 30.6 ± 5.1° in brace, p < 0.001). The estimated mean elasticity value of the paraspinal muscles was lower in the surgery group at baseline on the convex side (15.8 vs. 22.8 kPa, p = 0.037) and 6 months on both the concave (12.1 vs. 22.7 kPa, p = 0.004) and convex (13.4 vs. 23.8 kPa, p = 0.005) sides. There was a significant stiffness decrease from baseline to 6 months on the concave side in the surgery group (5.9 kPa, p = 0.025). However, the elasticity change recovered at 12 months without significant differences between the two groups.

Elasticity and cross-sectional thickness of paraspinal muscles in progressive adolescent idiopathic scoliosis

Objectives

(1) Compare the cross-sectional thickness (CST) and shear wave speed (SWS) of paraspinal muscles (PSM) in adolescent idiopathic scoliosis (AIS) with and without curve progression; (2) investigate the relationship between CST/SWS and radiographic characteristics in AIS with curve progression; (3) compare the CST/SWS between AIS and non-scoliosis controls.

Methods

This cross-sectional study analyzed the CST and SWS of PSM in 48 AIS with mild to moderate curvature and 24 non-scoliosis participants. Participants with scoliosis greater than 45° of Cobb angles were excluded. The Change of Cobb angles within the last 6-months was retrieved to allocate AIS into progression and non-progression groups. The SWS and CST of multifidus; longissimus and iliocostalis of the major curve were measured using B-mode ultrasound image with an elastography mode. Discrepancies of the SWS (SWS-ratio: SWS on the convex side divided by SWS on the concave side) and CST (CST-ratio: CST on the convex side divided by CST on the concave side) at the upper/lower end and apical vertebrae were studied.

Results

A higher SWS at the apical vertebrae on the concave side of the major curve (multifidus: 3.9 ± 1.0 m/s vs. 3.1 ± 0.6 m/s; p < 0.01, longissimus: 3.3 ± 1.0 m/s vs. 3.0 ± 0.9 m/s; p < 0.01, iliocostalis: 2.8 ± 1.0 m/s vs. 2.5 ± 0.8 m/s; p < 0.01) was observed in AIS with curve progression. A lower SWS-ratio at apical vertebrae was detected with a greater vertebral rotation in participants with curve progression (multifidus [grade II]: 0.7 ± 0.1 vs. grade I: 0.9 ± 0.2; p = 0.03, longissimus [grade II]: 0.8 ± 0.2 vs. grade I: 1.1 ± 0.2; p < 0.01). CST was not different among the progressive, non-progressive AIS and non-scoliosis controls.

Conclusions

Increased SWS of PSM without change of CST was observed on the concave side of the major curve in participants with progressive AIS.

The Effect of Leg Length Discrepancy on Paraspinal Muscles Activation Using Surface Electromyography

OBJECTIVE

The aim of the study is to assess the effects of leg length discrepancy on paraspinal muscle activity and kinematic variables during gait.

DESIGN

Thirty-nine healthy participants aged 5-12 yrs performed the 10-m walk test using the surface electromyography and G-walk sensor for the following conditions: (1) non-leg length discrepancy condition (leg length discrepancy 0 cm) and (2) leg length discrepancy condition with an insole on the right leg at three different heights (leg length discrepancy 0.5 cm, 1.0 cm, and 1.5 cm). The root mean square was normalized using maximal voluntary contraction and reference voluntary contraction methods (RMS_MVC and RMS_ref) and compared between the sides.

RESULTS

The mean RMS_MVC of the 12th thoracic erector spinae on the right side was significantly higher at a leg length discrepancy 0.5 cm and 1 cm. Regarding the 3rd lumbar multifidus, the mean RMS_MVC on the right side was significantly higher at a leg length discrepancy 1.5 cm. The mean RMS_ref exhibited similar patterns. Pelvic obliquity and rotation showed asymmetry at a leg length discrepancy 1.5 cm compared with a leg length discrepancy 0 cm.

CONCLUSIONS

A small leg length discrepancy significantly affected the asymmetric hyperactivation of the 3rd lumbar multifidus and 12th thoracic erector spinae muscles during gait. Considering the action of these muscles, asymmetric hyperactivation might result in rotation and bending of the lumbar spine and the bending of the thoracolumbar spine.

Myomodulation Using Botulinum Toxin in Septorhinoplasty for Crooked Noses: Introducing the Concept and Application of Nasal Muscle Imbalance Theory

The role of septorhinoplasty for adequate correction of deviated nose is well documented, but the rationales and patterns for recurrences after proper rhinoplasty remain unclear. There has also been little attention given to the influence of nasal musculatures on the stability of nasal structures after septorhinoplasty. The aim of this article is to propose our nasal muscle imbalance theory, which may explain the potential reason for redeviation of the noses in the initial period after septorhinoplasty. We postulate that in a chronically deviated nose, the nasal muscles on the convex side will be stretched and develop hypertrophy after prolonged period of increased contractile activity. On the contrary, the nasal muscles on the concave side will undergo atrophy due to reduced load requirement. In the initial period of recovery after a septorhinoplasty to bring the nose back to midline, this muscle imbalance is still uncorrected with unequal pulling forces on the nasal structure because the stronger nasal muscles on the previously convex side is still hypertrophied and exert stronger forces compared with the previously concave side, therefore increasing the risk of redeviation of the nose back to the preoperative side until muscle atrophy occurs in the convex side and a balanced nasal muscle pull is achieved. We believe that postseptorhinoplasty botulinum toxin injections can be used as an adjunct in rhinoplasty surgery to effectively block the pulling actions of the stronger or overacting nasal muscles by speeding up the atrophy process while allowing patient's nose to heal and stabilize in the desired position. However, further studies to objectively confirm this hypothesis is required, which include comparing topographic measurements, imaging and electromyography signals before and after injections in postseptorhinoplasty patients. The authors have already planned a multicenter study to further evaluate this theory.

Imaging study of coccygeal morphology in adolescent idiopathic scoliosis

The correlation between scoliosis and sagittal curvature of the cervical, thoracic, and lumbar spine have already been reported in previous studies. However, as a part of the spine, the change in coccygeal morphology in AIS patients has not yet been studied. In this study, a retrospective analysis was performed on 400 patients who were divided into a non-scoliotic group (206 patients) and an AIS group (194 patients). The Postacchini coccygeal radiological classification that was modified by Nathan was used to observe and compare the sagittal coccygeal morphology between the two groups. The results showed that the non-scoliotic group had the highest percentage (52.4%) of patients with type I and the lowest (3.4%) proportion of patients with type V; moreover, the AIS group had the highest percentage (69.1%) of patients with type I and the lowest (1.5%) proportion of patients with type V. The coccygeal morphology was significantly different between the non-scoliotic group and the AIS group (P = 0.001). No significant differences in coccygeal morphology were found between the males and females in the two groups (mild and moderate scoliosis and different segmental scoliosis). In addition, a significant correlation between coccygeal morphology and scoliosis (P = 0.035) was found. In conclusion, coccygeal morphology significantly differs between AIS patients and non-scoliotic adolescents. There was a smaller proportion of patients with a type I coccyx and a larger proportion of patients with a type II or type III coccyx in the AIS group than in the non-scoliotic group. In other words, the presence of a more pronounced coccygeal curve in AIS patients may be caused by an incorrect sitting position and an imbalance in the contraction of the pelvic muscles. It should be further studied whether correcting the sitting position and muscular imbalances could change coccygeal morphology and subsequently affect the development of AIS.

Quantifying Muscle Size Asymmetry in Adolescent Idiopathic Scoliosis Using Three-dimensional Magnetic Resonance Imaging

STUDY DESIGN

This is a case-control study of prospectively collected data.

OBJECTIVE

To quantify paraspinal muscle size asymmetry in adolescent idiopathic scoliosis (AIS) and determine if this asymmetry is (i) greater than observed in adolescent controls with symmetrical spines; and (ii) positively associated with skeletal maturity using Risser grade, scoliosis severity using the Cobb angle, and chronological age in years.

SUMMARY OF BACKGROUND DATA

AIS is a three-dimensional deformity of the spine which occurs in 2.5% to 3.7% of the Australian population. There is some evidence of asymmetry in paraspinal muscle activation and morphology in AIS. Asymmetric paraspinal muscle forces may facilitate asymmetric vertebral growth during adolescence.

METHODS

An asymmetry index [Ln(concave/convex volume)] of deep and superficial paraspinal muscle volumes, at the level of the major curve apex (Thoracic 8-9 th vertebral level) and lower-end vertebrae ( LEV , Thoracic 10-12 th vertebral level), was determined from three-dimensional Magnetic Resonance Imaging of 25 adolescents with AIS (all right thoracic curves), and 22 healthy controls (convex=left); all female, 10 to 16 years.

RESULTS

Asymmetry index of deep paraspinal muscle volumes was greater in AIS (0.16±0.20) than healthy spine controls (-0.06±0.13) at the level of the apex ( P <0.01, linear mixed-effects analysis) but not LEV ( P >0.05). Asymmetry index was positively correlated with Risser grade ( r =0.50, P <0.05) and scoliosis Cobb angle ( r =0.45, P <0.05), but not age ( r =0.34, P >0.05). There was no difference in the asymmetry index of superficial paraspinal muscle volumes between AIS and controls ( P >0.05).

CONCLUSIONS

The asymmetry of deep apical paraspinal muscle volume in AIS at the scoliosis apex is greater than that observed at equivalent vertebral levels in controls and may play a role in the pathogenesis of AIS.

Handgrip strength assessment at baseline in addition to bone parameters could potentially predict the risk of curve progression in adolescent idiopathic scoliosis

Introduction

Adolescent idiopathic scoliosis (AIS) is characterized by deranged bone and muscle qualities, which are important prognostic factors for curve progression. This retrospective case-control study aims to investigate whether the baseline muscle parameters, in addition to the bone parameters, could predict curve progression in AIS.

Methods

The study included a cohort of 126 female patients diagnosed with AIS who were between the ages of 12 and 14 years old at their initial clinical visit. These patients were longitudinally followed up every 6 months (average 4.08 years) until they reached skeletal maturity. The records of these patients were thoroughly reviewed as part of the study. The participants were categorized into two sub-groups: the progressive AIS group (increase in Cobb angle of ≥6°) and the stable AIS group (increase in Cobb angle <6°). Clinical and radiological assessments were conducted on each group.

Results

Cobb angle increase of ≥6° was observed in 44 AIS patients (34.9%) prior to skeletal maturity. A progressive AIS was associated with decreased skeletal maturity and weight, lower trunk lean mass (5.7%, p = 0.027) and arm lean mass (8.9%, p < 0.050), weaker dominant handgrip strength (8.8%, p = 0.027), deranged cortical compartment [lower volumetric bone mineral density (vBMD) by 6.5%, p = 0.002], and lower bone mechanical properties [stiffness and estimated failure load lowered by 13.2% (p = 0.005) and 12.5% (p = 0.004)]. The best cut-off threshold of maximum dominant handgrip strength is 19.75 kg for distinguishing progressive AIS from stable AIS (75% sensitivity and 52.4% specificity, p = 0.011).

Discussion

Patients with progressive AIS had poorer muscle and bone parameters than patients with stable AIS. The implementation of a cut-off threshold in the baseline dominant handgrip strength could potentially be used as an additional predictor, in addition to bone parameters, for identifying individuals with AIS who are at higher risk of experiencing curve progression.

Lower limb joint burden during walking in adolescent idiopathic scoliosis: investigation of mechanical work during walking

BACKGROUND CONTEXT

Adolescent idiopathic scoliosis (AIS) is the most prevalent spinal deformity in adolescents. However, pathophysiology and long-term complications remain unclear. Characteristics of the mechanical work in AIS gait have not been well-studied.

PURPOSE

This study aimed to elucidate the characteristics of mechanical work in AIS gait.

STUDY DESIGN

Observational comparison study.

PATIENT SAMPLE

Participants were composed of two groups: scoliosis group with 68 participants and a control group with 17 participants.

OUTCOME MEASURES

Spinal deformity and coronal spinal balance in the scoliosis group were assessed with Cobb angle, coronal balance, and apical vertebra translation. Three-dimensional motion analysis during walking was conducted to calculate lower limb joint works and external work on the whole body's center of mass.

METHODS

Lower limb joint work (JW) and external work on the whole body center of mass (CoM) were compared between the 2 groups with an independent t-test. Inter-limb and intra-limb comparisons of mechanical work were conducted with a paired t-test. The relationships between mechanical work and frontal trunk deformity were investigated in the scoliosis group.

RESULTS

Walking speed and external work on whole body CoM did not differ between the two groups. Compared to the control group, the scoliosis group showed significantly larger JW on the convex and concave sides.

CONCLUSION

The scoliosis group showed increased lower limb joint burden and limited trunk function for mechanical work during walking. Investigation of mechanical work during walking provides insight into the biomechanical characteristics of AIS. Therefore, future studies should be conducted to verify mechanical work characteristics which have relevance to the progression of spinal deformity and the development of lower limb complications in AIS.

Adolescent idiopathic scoliosis is associated with muscle area asymmetries in the lumbar spine

PURPOSE

While the etiopathogenesis of adolescent idiopathic scoliosis (AIS) remains unclear, it is assumed that muscular asymmetries contribute to curve progression. As previous studies have found asymmetries of the thoracic paraspinal muscles in AIS patients, our study's aim was to analyze differences in the erector spinae, multifidus, quadratus lumborum, and psoas muscles of the lumbar spine depending on the curve's radiographic characteristics.

METHODS

We retrospectively included all patients who received posterior reposition spondylodesis for AIS treatment at our institution. Patients were classified according to the Lenke classification. Muscle cross-sectional areas were obtained from magnetic resonance imaging of the lumbar spine. Data were analyzed with the Wilcoxon rank sum test, the Kruskal-Wallis test with post hoc testing, or the Spearman's correlation coefficient.

RESULTS

Seventy-four (14 males and 60 females) AIS patients with a median age of 16 (IQR ± 4) years and a mean Cobb angle of 56.0° (± 18.0°) were included. In curve types Lenke 1 and 2 (n = 45), the erector spinae (p < 0.001) and multifidus (p < 0.001) muscles had a significantly larger cross-sectional area on the convex side, whereas the quadratus lumborum (p = 0.034) and psoas (p < 0.001) muscles each had a significantly larger cross-sectional area on the lumbar contralateral side.

CONCLUSION

Our results show an asymmetry of the lumbar spine's muscles which depends on both the convexity and the extent of the scoliotic curve. While our results cannot prove whether these differences are the deformity's cause or effect, they may contribute to a better understanding of AIS pathogenesis and may allow for more specific preoperative physiotherapy.

Assessment of the functional state of the back muscles in girls with C-shaped low-grade scoliosis in a tensiomyographic image: An observational cross-sectional study

PURPOSE

The study aimed to test the feasibility of using tensiomyography to assess the functional status of the latissimus dorsi and erector spinae muscles in girls with C-shaped low back scoliosis.

MATERIALS AND METHODS

Twenty-five girls aged 13-15 took part in an observational (cross-sectional) study. The examination involved measurements using the tensiomyography method (TMG). Two groups of muscles were tested: latissimus dorsi and erector spinae on the concave and convex side of low-grade scoliosis. The following indicators were analyzed: Td-delay time, Tc-contraction time, and Dm-maximal muscle displacement.

RESULTS

The analysis of Td revealed that values of this variable on the concave side were slightly lower compared to the convex side in both tested groups of muscles. Similarly, Tc values on the concave side were slightly lower than on the convex side of the curvature in both groups of muscles. In the case of Dm, lower displacement values and, consequently, greater muscle rigidity were observed on the concave side of the latissimus dorsi and the convex side of the erector spinae.

CONCLUSIONS

The TMG method can be potentially used to diagnose the functional condition of muscles in patients with low-grade scoliosis. There were differences between the functional condition of the muscles on the concave and convex sides of the curvature.

Is Obstructive Sleep Apnea-Associated Adenoid Hypertrophy Linked to Scoliotic Attitudes in Children?

Introduction Scoliosis, a multifaceted spinal deformity commonly affecting pediatric and adolescent populations, has spurred extensive scientific inquiry to understand its origins and impacts. Early-onset scoliosis (EOS), characterized by spinal curvature exceeding 10° before the age of 10, presents a unique challenge necessitating a comprehensive understanding of its etiological factors. Within this context, the potential role of hypoxia-induced by adenoid hypertrophy in contributing to the pathogenesis of EOS has emerged as an intriguing avenue of investigation. Materials and methods This retrospective study was conducted focusing on radiological and clinical data pertaining to children below 10 years of age who underwent isolated adenoidectomy for adenoid hypertrophy. Preoperative posteroanterior standing chest radiographs were utilized for scoliosis assessment, with Cobb angles serving as the primary measurement metric. To ensure accuracy and reliability, Cobb angle measurements were independently performed by two experienced observers. Statistical analyses encompassed the Mann-Whitney U test, Spearman correlation analysis, and intraclass correlation coefficient calculations to evaluate interobserver agreement. Results Among the cohort of 218 pediatric adenoidectomy patients, 177 individuals had radiographs suitable for EOS evaluation. The mean age of the participants was 5.72±2 years, with a nearly equal distribution of 52.5% male and 47.5% female patients. Strikingly, the study identified a 10.2% prevalence of coronal plane curvatures exceeding the critical threshold of 10°, indicative of EOS. The robust interobserver reliability was demonstrated by a commendable mean interclass correlation coefficient (ICC) value of 0.926, affirming consistent and accurate Cobb angle measurements between the observers. Conclusion In light of the heightened prevalence of EOS observed in children undergoing adenoidectomy, this study provides a compelling impetus for exploring the potential interrelationship between adenoid hypertrophy, hypoxia, and the emergence of early-onset scoliosis. The study underscores the importance of prospective research to elucidate the complex mechanisms connecting these factors, offering insights into potential risk factors and underlying pathogenic pathways associated with the development of early-onset scoliosis.

Reduced volume and altered composition of paraspinal muscles in Marfan syndrome: A retrospective cohort study

Retrospective cohort study. Spinal deformities in patients with Marfan syndrome (MFS) are distinct from those in patients with idiopathic scoliosis (IS). It is more prone to progression and more likely to present with sagittal malalignment than IS. However, the etiology of this characteristic spinal deformity in MFS remains unclear. This study aimed to determine the spinal musculature characteristics in patients with MFS on the hypothesis that the paraspinal muscles of patients with MFS would be qualitatively or quantitatively different from those of patients with IS. Seventeen consecutive patients with MFS aged 25 years or younger undergoing surgery for scoliosis in our hospital were compared with age- and sex-matched patients with IS undergoing surgery for scoliosis. The body size-adjusted relative cross-sectional area (rCSA), fatty infiltration ratio (FI%), and relative functional cross-sectional area (rFCSA) of the psoas muscles (PM) and paravertebral muscles (PVM) at L3/4 and L4/5 were measured using preoperative T2-weighted magnetic resonance imaging. Functional CSA was defined as total CSA minus the fatty infiltration area of each muscle and rFCSA was calculated as the body size-adjusted functional CSA. The rCSA of the PM at L3/4 and L4/5 was significantly smaller in the MFS group than in the IS group (L3/4, P = .021; L4/5, P = .002). The FI% of the PM at L4/5 was significantly higher in the MFS group (P = .044). Consequently, the rFCSA of the PM at L3/4 and L4/5 and the rFCSA of the PVM at L3/4 in the MFS group were significantly smaller than those in the IS group (PM at L3/4, P = .021; PM at L4/5, P = .001; PVM at L3/4, P = .025). Compared with patients with IS, patients with MFS exhibited significantly decreased body-size-adjusted CSA of the PM and reduced body-size-adjusted functional CSA of the PVM and PM. These findings may partially explain the characteristics of distinctive spinal deformities in patients with MFS.

Pediatric Sleep Questionnaire for Sleep Apnea in Newly Diagnosed Adolescent Idiopathic Scoliosis Patients

Close association has been established between obstructive sleep apnea (OSA) and adolescent idiopathic scoliosis (AIS), with PSQ being employed as a screening method for OSA. A cross-sectional study was conducted among patients aged from 10 to 16 years who presented to a scoliosis outpatient clinic. Patient demographics, radiological assessments, and PSQ scores were gathered. A total of 299 patients were included in the study, with 28.7% males and 71.2% females. The average Cobb angle was 6.20°. PSQ scores revealed a prevalence of 33.4% for significant obstructive sleep apnea. Patients diagnosed with AIS exhibited a prevalence of 32.9% with positive PSQ results. Among those undergoing adenoid and/or tonsil surgery, 27% had positive PSQ scores. Factors such as genetics, abnormal biomechanical forces, environmental factors including melatonin, and intermittent hypoxia were explored for their potential contribution to AIS etiology. The aim of the study is to underscore the importance of early detection and intervention in OSA cases and highlights the effectiveness of the PSQ, as a screening tool in identifying sleep disorders. The findings underscore the complex relationship between OSA and AIS, and moreover any spinal curvature is in relation with OSA.

Proteomic Comparison of Paraspinal Muscle Imbalance Between Idiopathic Scoliosis and Congenital Scoliosis

OBJECTIVE

This study aims to compare the proteomic profiles of paraspinal muscle imbalance between idiopathic scoliosis (IS) and congenital scoliosis (CS).

METHODS

Bilateral paraspinal muscles of 5 pairs of matched IS and CS patients were collected. Proteome patterns of paraspinal muscles were established. Differentially expressed proteins (DEPs) in paraspinal muscles between the convexity and the concavity were screened out. DEPs shared by both IS and CS and IS-specific DEPs were identified. Bioinformatic analyses of DEPs were performed.

RESULTS

Among 105 DEPs identified in IS, 30 displayed predominant expression on the convexity, whereas other 75 exhibited predominant expression on the concavity. DEPs in IS were mainly enriched in calcium ion binding and DNA binding in gene ontology (GO) term and glycolysis/gluconeogenesis and purine metabolism in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Among 48 DEPs identified in CS, 25 were predominantly expressed on the convexity and 23 on the concavity. DEPs in CS were mainly enriched in receptor activity and immune response in GO term and glycolysis/gluconeogenesis and cellular senescence in KEGG pathway. Comparison of DEPs between IS and CS identified only 8 proteins shared by both types of scoliosis. Among the 97 IS-specific DEPs, 28 were predominantly expressed on the convexity and 69 on the concavity. IS-specific genes were enriched in calcium ion binding and protein glycosylation in GO term and glycolysis/gluconeogenesis and hypertrophic cardiomyopathy in KEGG pathway.

CONCLUSION

IS and CS exhibit proteomic imbalance in bilateral paraspinal muscles but share few similarities. Paraspinal muscle imbalance in IS might not be the consequence of spinal deformities.

The asymmetrical ESR1 signaling in muscle progenitor cells determines the progression of adolescent idiopathic scoliosis

Adolescent Idiopathic Scoliosis (AIS) is a common pediatric skeletal disease highly occurred in females. The pathogenesis of AIS has not been fully elucidated. Here, we reveal that ESR1 (Estrogen Receptor 1) expression declines in muscle stem/progenitor cells at the concave side of AIS patients. Furthermore, ESR1 is required for muscle stem/progenitor cell differentiation and disrupted ESR1 signaling leads to differentiation defects. The imbalance of ESR1 signaling in the para-spinal muscles induces scoliosis in mice, while reactivation of ESR1 signaling at the concave side by an FDA approved drug Raloxifene alleviates the curve progression. This work reveals that the asymmetric inactivation of ESR1 signaling is one of the causes of AIS. Reactivation of ESR1 signaling in para-spinal muscle by Raloxifene at the concave side could be a new strategy to treat AIS.

Characteristics of the paravertebral muscle in adult degenerative scoliosis with PI-LL match or mismatch and risk factors for PI-LL mismatch

Objective

Pelvic incidence (PI) minus the lumbar lordosis (LL) angle (PI-LL) correlates with function and disability. It is associated with paravertebral muscle (PVM) degeneration and is a valuable tool for surgical planning of adult degenerative scoliosis (ADS). This study aims to explore the characteristics of PVM in ADS with PI-LL match or mismatch and to identify the risk factors for PI-LL mismatch.

Methods

A total of 67 patients with ADS were divided into PI-LL match and mismatch groups. The visual analog scale (VAS), symptom duration, and Oswestry disability index (ODI) were used to assess patients’ clinical symptoms and quality of life. The percentage of fat infiltration area (FIA%) of the multifidus muscle at the L1-S1 disc level was measured by using MRI with Image-J software. Sagittal vertical axis, LL, pelvic tilt (PT), PI, sacral slope, and the asymmetric and average degeneration degree of the multifidus were recorded. Logistic regression analysis was done to identify the risk factors for PI-LL mismatch.

Results

In the PI-LL match and mismatch groups, the average FIA% of the multifidus on the convex side was less than that on the concave side (P &lt; 0.05). There was no statistical difference of asymmetric degeneration degree of the multifidus between the two groups (P &gt; 0.05). In the PI-LL mismatch group, the average degeneration degree of the multifidus, VAS, symptom duration, and ODI were significantly higher than that in the PI-LL match group, respectively (32.22 ± 6.98 vs. 26.28 ± 6.23 (%), 4.33 ± 1.60 vs. 3.52 ± 1.46, 10.81 ± 4.83 vs. 6.58 ± 4.23 (month), 21.06 ± 12.58 vs. 12.97 ± 6.49, P &lt; 0.05). The average degeneration degree of the multifidus muscle was positively correlated with the VAS, symptom duration, and ODI, respectively (r = 0.515, 0.614, and 0.548, P &lt; 0.05). Sagittal plane balance, LL, PT, and the average degeneration degree of the multifidus were the risk factors for PI-LL mismatch (OR: 15.447, 95% CI: 1.274–187.269; OR: 0.001, 95% CI: 0.000–0.099; OR: 107.540, 95% CI: 5.195–2,225.975; OR: 52.531, 95% CI: 1.797–1,535.551, P &lt; 0.05).

Conclusion

The PVM on the concave side was larger than that on the convex side in ADS irrespective of whether PI-LL matched or not. PI-LL mismatch could aggravate this abnormal change, which is an important cause of pain and disability in ADS. Sagittal plane imbalance, decreased LL, higher PT, and larger average degeneration degree of the multifidus were independent risk factors for PI-LL mismatch.

Quantitative Study of Vertebral Body and Paravertebral Muscle Degeneration Based on Dual-Energy Computed Tomography: Correlation With Bone Mineral Density

OBJECTIVES

This study aimed to quantify the degeneration of the vertebral body and paravertebral muscles using dual-energy computed tomography (DECT) and study its relationship with osteoporosis.

METHODS

A total of 130 patients with chronic low back pain were included in this study, and DECT scanning of the lumbar region was undertaken prospectively. By placing a standard quantitative computed tomography corrected phantom under the waist during the DECT procedure, bone mineral density (BMD) and the following quantitative parameters were obtained: calcium density (CaD), vertebral fat fraction (VFF), psoas major area, psoas major fat fraction, erector spinalis area, and erector spinalis fat fraction (ESFF). Independent sample t test and 1-way analysis of variance were used between different age-BMD groups. Pearson test was applied to determine correlations for all measurements, and a mathematical model of BMD was established through regression analysis.

RESULTS

Calcium density, VFF, psoas major area, psoas major fat fraction, erector spinalis area, and ESFF were significantly different among the age-BMD groups (P < 0.05), and BMD was significantly correlated with these parameters (P < 0.05). Calcium density, VFF, and ESFF were included in the BMD regression equation: BMD = 69.062 + 11.637 × CaD - 1.018 × VFF - 0.726 × ESFF (R2 = 0.860, F = 125.979, P < 0.001).

CONCLUSIONS

Degeneration of the vertebral body and paravertebral muscles can be quantitatively analyzed using DECT, and CaD, VFF, and ESFF were independent influencing factors of BMD.

The use of MRI in the study of patients with idiopathic scoliosis: a systematic review of the literature

Objective. To analyze the frequency of hidden neuraxial pathology in idiopathic scoliosis (IS), to substantiate the need for MRI in IS and to identify promising areas for the use of MRI in the examination of patients with IS.Material and Methods. The literature review was carried out using the PubMed and Google Scholar databases. Of the 780 papers on the research topic, 65 were selected after removing duplicates and checking for inclusion/exclusion criteria. As a result, 49 original studies were included in the analysis. Level of evidence – II.Results. According to modern literature, the main direction of using MRI in idiopathic scoliosis is the search for predictors of latent pathology of the spinal cord and craniovertebral junction. The frequency of neuraxial pathology in idiopathic scoliosis is 8 % for adolescent IS and 16 % for early IS. The main predictors of neuraxial pathology are male sex, early age of deformity onset, left-sided thoracic curve and thoracic hyperkyphosis. MRI in IS may be a useful addition to radiological diagnostic methods to identify risk factors and to study degenerative changes in the spine.Conclusion. MRI of the spine should be performed in the early stages of IS to detect latent spinal cord tethering. In type I Chiari anomalies, there is a possibility that early neurosurgery can prevent the development of scoliosis. The main signs of latent neuraxial pathology in IS are early progression of spinal deformity, left-sided thoracic curve, male gender and thoracic kyphosis over 40° according to Cobb.MRI can be used as an effective non-invasive tool in research aimed at identifying risk factors for IS, including helping to track early degeneration of intervertebral discs.

Effectiveness of Botulinum Neurotoxin in Treatment of Scoliosis among Children and Adolescents: A Systematic Review and Meta-Analysis

Scoliosis refers to a three-dimensional deviation in the axis of the spine. Muscle imbalance is believed to play a role in scoliosis. Botulinum neurotoxin (BoNT) can reduce muscle overactivity and may have the potential to ameliorate spinal scoliosis. This study investigated the effectiveness of intramuscular BoNT injection in vertebral curve correction and reviewed the possible influencing factors. PubMed, Medline, Cochrane Central Register of Controlled Trials, Web of Science, Airiti Library, and Index of the Taiwan Periodical Literature System databases were searched from inception until 7 September 2022 for eligible studies. The main outcome was the change in Cobb angle after BoNT application. Subgroup analysis was conducted according to differences in study designs, etiology of scoliosis, and methods used for target muscle selection. We enrolled three studies including 31 participants aged between 2 and 18 years. The meta-analysis revealed no significant reduction in the Cobb angle after BoNT injection (standardized mean difference, −0.783, 95% CI, −2.142 to 0.576). Study designs (p = 0.011) and methods used for target muscle selection (p = 0.017) but not etiology of scoliosis (p = 0.997) reached statistical significance between subgroups. In conclusion, the current meta-analysis does not support the application of BoNT in children and adolescents with scoliosis. However, a decisive conclusion could not be made due to high between-study heterogeneity and small sample size. More randomized controlled trials with appropriate target muscle selection and standard outcome measurement should be conducted to examine the efficacy of botulinum neurotoxin in treating scoliosis. INPLASY ID: INPLASY202290031.

Comparison of multifidus degeneration between scoliosis and lumbar disc herniation

Objective

To assess and compare the pathological and radiological outcomes of multifidus degeneration in scoliosis and lumbar disc herniation patients.

Methods

We performed a retrospective review on 24 patients with scoliosis and 26 patients with lumbar disc herniation (LDH) in the Third Hospital of Hebei Medical University from January 2017 to March2021. The patients were divided into scoliosis group and LDH group according to the treatment. The MRI fatty infiltration rate (FIR) of multifidus and strength of back muscle were calculated to evaluate muscle condition. Multifidus biopsy samples were obtained during surgery in the affected side at L4 or L5 segment in LDH group and on the concavity side of apical vertebrae in scoliosis group. The biopsy fatty infiltration degree (FID) and FIR in two groups, the FIR of affected and unaffected side in LDH group, and the FIR of concavity and convexity side in scoliosis group were compared. The correlation between concavity-convexity FIR difference and cobb angle in scoliosis group, back muscle strength and FIR in LDH group, FID and FIR in both groups was calculated respectively.

Results

The FIR was higher in scoliosis group than in LDH group, higher in concavity side than convexity side in scoliosis group (both P < 0.05). The FID was higher in scoliosis group than in LDH group (P < 0.05). No significant difference was found between affected and unaffected side in LDH group (P > 0.05). There was a positive correlation between concavity-convexity FIR difference and cobb angle, FIR and FID (both P < 0.01). There was a negative correlation between back muscle strength and FIR (P < 0.01). The biopsy staining results showed that both two groups were found the existence of rimmed vacuoles, nuclear aggregation, and abnormal enzyme activity, indicating that the scoliosis and LDH may be associated with myogenic diseases.

Conclusion

The scoliosis patients showed more serious fatty infiltration than LDH patients and rare pathological findings were found in both diseases.

Biological effect of dysregulated LBX1 on adolescent idiopathic scoliosis through modulating muscle carbohydrate metabolism

BACKGROUND CONTEXT

Abnormal energy metabolism such as lower body weight and body mass index (BMI) and less fat mass is widely reported in patients with adolescent idiopathic scoliosis (AIS) and has been implicated in deformity development. However, the underlying mechanism is largely unclear. LBX1 is one of the promising AIS predisposing genes validated by multicenter studies.

PURPOSE

This study aimed to identify differentially expressed proteins (DEPs) relating to energy metabolism in AIS by using proteomic and metabolic analysis and to explore if the expression of these DEPs is associated with clinical parameters and modulated by LBX1.

STUDY DESIGN

This is a cross-sectional study using clinical data and biological samples followed by basic study using a cellular model.

PATIENT SAMPLE

Plasma samples were collected from Chinese girls with nonprogressive and progressive AIS (N=7 and 8, respectively) and age-matched healthy girls (N=50). Paraspinal muscle tissues were collected intraoperatively from concave and convex side of the apex of the major spinal curve in AIS (N=24) and either side from nonscoliosis patients (N=14).

OUTCOME MEASURES

Radiological Cobb angle and basic anthropometric data of recruited subjects were measured. The DEPs and metabolites were compared in plasma using proteomics and metabolomics technique. The relative expression of selected genes was measured in muscles.

METHODS

Plasma samples from AIS were collected at first clinical visit and were further divided into nonprogressive or progressive groups according to Cobb angle changes in 6-year follow-up. Age-matched healthy girls were recruited as control. High-performance liquid chromatography-mass spectrometry based proteomic analysis was carried out in three groups to identify DEPs and their annotated metabolic pathways. An independent cohort was used for validation by gas chromatography-mass spectrometry based metabolomic analysis. Paraspinal muscles were subjected to quantitative polymerase chain reaction (qPCR) followed by correlation analysis. Human skeletal muscle myoblast (HSMM) was used as the cellular model.

RESULTS

The likelihood of aberrant galactose metabolism and glycolysis was found to be associated with AIS curve progression as evidenced by the thirteen DEPs and seven related metabolites according to proteomic and metabolomic analysis. Some of the DEPs showed significantly altered expression in AIS concave and convex sides paraspinal muscles compared with those in nonscoliosis control. Four DEPs were found significantly and negatively correlated with LBX1 in AIS convex side paraspinal muscles. Overexpressing LBX1 in HSMM cells led to increased expression of three DEPs and decreased expression of three DEPs, respectively.

CONCLUSIONS

This is the first integrated proteomic and metabolomic analysis on AIS. Our findings show dysregulated galactose metabolism and glycolysis pathways in progressive group of AIS, suggesting the presence of abnormal energy metabolism at early stage of this disease, and their association with higher risk of progressing into more severe curvature. Evidence from ex vivo study with human muscle biopsies and in vitro study with human myoblast cells propose the possible effect of LBX1 on these two pathways in skeletal muscles. The present study provides new evidence of LBX1 function in AIS via modulating effect on the expression of energy metabolism related genes. This study might provide new insights into etiopathogenesis and development of novel treatment strategy targeting on abnormal body weight and BMI in patients with AIS. Additionally, the plasma proteomic and metabolomic studies suggested new candidates as biomarkers for establishing predictive model for AIS onset/progression.

Association of LBX1 Gene Methylation Level with Disease Severity in Patients with Idiopathic Scoliosis: Study on Deep Paravertebral Muscles

Idiopathic scoliosis (IS) is a multifactorial disease with a genetic background. The association of Ladybird Homeobox 1 (LBX1) polymorphisms with IS has been proven in multiple studies. However, the epigenetic mechanisms have not been evaluated. This study aimed to evaluate the LBX1 methylation level in deep paravertebral muscles in order to analyze its association with IS occurrence and/or IS severity. Fifty-seven IS patients and twenty non-IS patients were examined for the paravertebral muscles’ methylation level of the LBX1 promoter region. There was no significant difference in methylation level within paravertebral muscles between patients vs. controls, except for one CpG site. The comparison of the paravertebral muscles’ LBX1 promoter region methylation level between patients with a major curve angle of ≤70° vs. >70° revealed significantly higher methylation levels in 17 of 23 analyzed CpG sequences at the convex side of the curvature in patients with a major curve angle of >70° for the reverse strand promoter region. The association between LBX1 promoter methylation and IS severity was demonstrated. In patients with severe IS, the deep paravertebral muscles show an asymmetric LBX1 promoter region methylation level, higher at the convex scoliosis side, which reveals the role of locally acting factors in IS progression.

Adolescent idiopathic scoliosis : a review of aetiological theories of a multifactorial disease

Adolescent idiopathic scoliosis (AIS), defined by an age at presentation of 11 to 18 years, has a prevalence of 0.47% and accounts for approximately 90% of all cases of idiopathic scoliosis. Despite decades of research, the exact aetiology of AIS remains unknown. It is becoming evident that it is the result of a complex interplay of genetic, internal, and environmental factors. It has been hypothesized that genetic variants act as the initial trigger that allow epigenetic factors to propagate AIS, which could also explain the wide phenotypic variation in the presentation of the disorder. A better understanding of the underlying aetiological mechanisms could help to establish the diagnosis earlier and allow a more accurate prediction of deformity progression. This, in turn, would prompt imaging and therapeutic intervention at the appropriate time, thereby achieving the best clinical outcome for this group of patients. Cite this article: Bone Joint J 2022;104-B(8):915-921.

A Novel Low-Cost 3D Printed Brace Design Method for Early Onset Scoliosis

Early onset scoliosis (EOS) is a type of spine deformity that presents before 10 years of age. The biomechanical properties in scoliosis have been found to be di?erent, especially in the case of the concave and convex paraverte-bral muscles. Based on this fact, a novel 3d printed patient-specific asymmetric stiffness brace design method is proposed in this paper, aiming to provide asymmetric stiffness to match "imbalanced" biomechanical properties of the concave and convex paravertebral muscles, respectively, and treat EOS by applying the block-structure brace.A 3d CAD draft model of the brace contour was implemented from 3D scanning. The asymmetric stiffness block-structure brace was designed in Rhinoceros and the Finite Ele-ment (FE) model was imported into ABAQUS. FE simulation was employed to study the mechanical characteristics of the brace, which provided a quan-titative index for the "imbalanced" property of brace stiffness. The results of the FE simulation showed that the stiffnesses of the concave and convex sides were 145.88 N/mm and 35.95 N/mm, respectively. The block-structure brace was fabricated using 3d printing. Asymmetric stiffness was evaluated by corrective force measurements, which were obtained from a thin-film pressure sensor equipped on the brace. The patient-specific asymmetric stiffness brace was applied to clinical practice in a one-year old EOS patient. A novel low-cost 3D printed brace design method for EOS was proposed in this study that could potentially be useful in patient treatment acceptance.

Synergy Analysis of Back Muscle Activities in Patients with Adolescent Idiopathic Scoliosis Based on High-Density Electromyogram

Adolescent idiopathic scoliosis (AIS) is a common structural spinal deformity and is typically associated with altered muscle properties. However, it is still unclear how muscle activities and the underlying neuromuscular control are changed in the entire scoliotic zone, restricting the corresponding pathology investigation and treatment enhancements. In this study, high-density electromyogram (HD-EMG) was utilized to explore the neuromuscular synergy of back muscle activities. For each of ten AIS patients and ten healthy subjects for comparison, a high-density electrode array was placed on their back from T8 to L4 to record EMG signals when performing five spinal motions (flexion/extension, lateral bending, axial rotation, siting, and standing). From the HD-EMG recordings, muscle synergies were extracted using the non-negative matrix factorization method and the topographical maps of EMG root-mean-square were constructed. For both the AIS and healthy subjects, the experimental results indicated that two muscle synergy groups could explain over 90% of recorded muscle activities for all five motions. During flexion/extension, the patients presented statistically significant higher activations on the convex side in the entire root-mean-square maps and synergy vector maps (p <0.05). During lateral bending and axial rotation, the patients exhibited less activated muscles on the dominant actuating side relative to the contralateral side and their synergy vector maps showed a less homogenous and more diffuse distribution of muscle contraction with statistically different centers of gravity. The findings suggest that a scoliotic spine might adopt an altered modular muscular coordination strategy to actuate different dominant muscles as adapted compensations for the deformation.

Potential Muscle-Related Biomarkers in Predicting Curve Progression to the Surgical Threshold in Adolescent Idiopathic Scoliosis-A Pilot Proteomic Study Comparing Four Non-Progressive vs. Four Progressive Patients vs. A Control Cohort

Previous studies have reported abnormal muscle morphology and functions in patients with adolescent idiopathic scoliosis (AIS). To answer whether such abnormalities could be reflected in their circulation and their clinical implication for predicting curve progression to the surgical threshold, this preliminary study explored the presence of baseline muscle-related proteins and their association with curve progression. Plasma samples were collected at the first clinical visit for AIS, with patients divided into non-progressive or progressive groups (N = four and four) according to their Cobb angle in six-year follow-ups, with age- and sex-matched healthy subjects (N = 50). Then, the samples were subjected to isobaric tags for relative and absolute quantitation (iTRAQ) for global comparison of untargeted protein expression. Seventy-one differentially expressed proteins (DEPs) were found elevated in progressive AIS. Functional analysis showed that 18 of these are expressed in muscles and play an essential role in muscle activities. Among the muscle-related DEPs, α-actin had the highest fold change in progressive/non-progressive groups. This preliminary study firstly suggested higher circulating levels of muscle structural proteins in progressive AIS, indicating the likelihood of structural damage at the microscopic level and its association with progression to the surgical threshold. Further studies with larger sample sizes are warranted to validate these novel candidates for early diagnosis and predicting progression.

Asymmetrical activation and asymmetrical weakness as two different mechanisms of adolescent idiopathic scoliosis

There have been many studies on adolescent idiopathic scoliosis related abnormal muscle contractions of the spine. However, previous studies using surface electromyography to investigate paraspinal muscle asymmetry are controversial, lacking in clarity of results, and hindered by methodological limitations. The purpose of this study was to investigate the relationship between imbalance factors including surface electromyography activity according to the scoliosis curve type and leg length discrepancy and adolescent idiopathic scoliosis curve types. Seventy-nine patients with scoliosis were prospectively enrolled and were divided into five types: single thoracic, thoracolumbar, lumbar, double thoracic, and double major. Cobb angle and structural variables were measured. Surface electromyography examinations were conducted at the 7th, 12th thoracic erector spinae, 3rd lumbar erector spinae, and multifidus muscles during the superman position keeping prone spinal extension to lift the arms and legs off the floor. Whole spine radiographs were obtained to measure the Cobb angle, coronal imbalance, pelvic height and angle, and femoral head height. In the double major, thoracolumbar, and lumbar types, the mean root mean squared (RMS) EMG amplitudes were significantly higher on the convex side than the concave side (P < 0.005). In the DM type, the mean RMS EMG amplitudes of ES_T7 and ES_L3 where the apex was located were significantly higher at the convex side than those of the concave side (P < 0.005, effect size (Cohen’s d) for ES_T7/ES_L3: 0.517/0.573). The TL and L types showed a similar pattern. The mean RMS EMG amplitudes of the ES_T12 concave side and Mu_L3 and ES_L3 concave sides were significantly lower than those of the convex side in the TL and L types, respectively (P < 0.008, effect size (Cohen’s d) for ES_T12/Mu_L3/ES_L3: 0.960/0.264/0.448). Conversely, there were no significant differences in the single thoracic and double thoracic types. All structural variables (coronal imbalance, pelvic height and angle, and femur head height) were higher in the lumbar type, but only coronal imbalance was significantly different (P < 0.05). Different patterns of asymmetry of paraspinal muscles and structural variables were described based on the curvature of the spine. L type showed that EMG activity was asymmetric in the paraspinalis muscles where the apex was located and that structural asymmetry, such as coronal imbalance was significantly greater than other types. DM type showed similar paraspinalis asymmetry pattern to the ST type but there was no structural asymmetry in DM and ST types. TL type has the features of both thoracic and lumbar origins. Understanding these could contribute to the management in correcting scoliosis.

Paraspinal muscle morphology and composition in adolescent idiopathic scoliosis: A histological analysis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a condition resulting in spinal deformity and tissue adaptation of the paraspinal muscles. Although prior studies have demonstrated asymmetries in fiber type and other energetic features of muscle on the concave side of the curve, muscle morphology, architecture, and composition have not been evaluated. Therefore, the purpose of this study was to compare differences in paraspinal muscle microarchitecture and composition between concave and convex sides of a scoliotic curve in individuals with AIS.

METHODS

Paraspinal muscle biopsies were obtained at the apex of the scoliotic curve in 29 individuals with AIS undergoing surgical deformity correction. Histological assays were performed to quantify fiber size, evidence of muscle degeneration and regeneration, and tissue composition (proportion of muscle, collagen, and fat). Differences between contralateral muscle samples were compared using two-tailed paired Student's t tests, and relationships between clinical characteristics (age and curve severity) and muscle characteristics were investigated using Pearson correlations.

RESULTS

Muscle fibers were significantly larger on the convex side of the curve apex (P = .001), but were lower than literature-based norms for healthy paraspinal muscle. There were no differences in amount of degeneration/regeneration (P = .490) or the proportion of muscle and collagen (P > .350) between the concave and convex sides, but high levels of collagen were observed. There was a trend toward higher fat content on the concave side (P = .074). Larger fiber size asymmetries were associated with greater age (r = .43, P = .046), and trended toward an association with greater curve severity (r = .40, P = .069).

CONCLUSIONS

This study demonstrates that although muscle fibers are larger on the convex side of the scoliotic curve in AIS, muscles on both sides are atrophic compared to non-scoliotic individuals, and demonstrate levels of collagen similar to severe degenerative spinal pathologies. These findings provide insight into biological maladaptations occurring in paraspinal muscle in the presence of AIS.

Methylation of Estrogen Receptor 1 Gene in the Paraspinal Muscles of Girls with Idiopathic Scoliosis and Its Association with Disease Severity

Idiopathic scoliosis (IS) is a multifactorial disease with epigenetic modifications. Tissue dependent and differentially methylated regions (T-DMRs) may regulate tissue-specific expression of the estrogen receptor 1 gene (ESR1). This study aimed to analyze methylation levels within T-DMR1 and T-DMR2 and its concatenation with ESR1 expression of IS patients. The study involved 87 tissue samples (deep paravertebral muscles, both on the convex and the concave side of the curve, and from back superficial muscles) from 29 girls who underwent an operation due to IS. Patient subgroups were analyzed according to Cobb angle ≤70° vs. >70°. Methylation was significantly higher in the superficial muscles than in deep paravertebral muscles in half of the T-DMR1 CpGs and all T-DMR2 CpGs. The methylation level correlated with ESR1 expression level on the concave, but not convex, side of the curvature in a majority of the T-DMR2 CpGs. The T-DMR2 methylation level in the deep paravertebral muscles on the curvature's concave side was significantly lower in patients with a Cobb angle ≤70° in four CpGs. DNA methylation of the T-DMRs is specific to muscle tissue location and may be related to ESR1 expression regulation. Additionally, the difference in T-DMR2 methylation may be associated with IS severity.

Assessment of the cross-sectional areas of the psoas major in patients with adolescent idiopathic scoliosis before skeletal maturity

BACKGROUND

The psoas major (PM) can support the lumbar spine and plays an important role in lumbar movement and maintaining lumbar curvature.

PURPOSE

To analyze morphological changes of PM and its relation with the severity of adolescent idiopathic scoliosis (AIS).

MATERIAL AND METHODS

The study was conducted on patients with AIS (age range = 10-18 years) with primary lumbar scoliosis. The cross-sectional area (CSA) of the PM at the L1-L5 levels were measured. The CSA of the PM in patients with AIS was compared with the average CSA of the PM in age-matched controls. The difference in PM at the apical vertebrae level was compared with the Cobb angle to determine the association between PM imbalance and severity of scoliosis.

RESULTS

The CSA of the PM was larger on the concave side than the convex side at the apical vertebrae level and other lumber levels. Patients with a larger Cobb angle had statistically higher PM imbalance at the apical vertebrae level. The CSA of the PM on both the concave and convex sides of patients with AIS were larger than the average CSA of controls aged 16-18 years; however, there was no significant difference between patients with AIS and controls aged 10-15 years.

CONCLUSION

There is a significant PM imbalance in patients with AIS before skeletal maturity, and the imbalance is related to the severity of scoliosis. The morphology of PM changed with the progression of scoliosis.

The effectiveness of two different exercise approaches in adolescent idiopathic scoliosis: A single-blind, randomized-controlled trial

OBJECTIVES

The purpose of this study was to compare the efficacy of two different types of exercise methods in patients with adolescent idiopathic scoliosis.

METHODS

In total, 28 subjects with adolescent idiopathic scoliosis with a mild curve magnitude (10°-26°) were randomly divided into two groups: the Schroth group (n = 14) and the core group (n = 14). The patients in the Schroth group were treated with supervised Schroth exercises, and the patients in the core group were treated with supervised core stabilization exercises; both groups performed the exercises for three days per week for a total of 10 weeks, and both were given additional traditional exercises to perform. Assessment included Cobb angle (Radiography), trunk rotation (Adam's test), cosmetic trunk deformity (Walter Reed Visual Assessment Scale), spinal mobility (Spinal Mouse), peripheral muscle strength (Biodex System 4-Pro), and quality of life (Scoliosis Research Society-22 questionnaire).

RESULTS

It was found that patients in the Schroth group showed greater improvement in Cobb angles, thoracic trunk rotation angle, cosmetic trunk deformity, spinal mobility, and quality of life than those in the core group (p<0.05), except for in lumbar trunk rotation angle. Peripheral muscle strength improvement was greater in the core group than in the Schroth group (p<0.05).

CONCLUSION

Schroth exercises are more effective than core stabilization exercises in the correction of scoliosis and related problems in mild adolescent idiopathic scoliosis, and core stabilization exercises are more effective than Schroth exercises in the improvement of peripheral muscle strength.

TRIAL REGISTRATION

NCT04421157.

Mapping of Back Muscle Stiffness along Spine during Standing and Lying in Young Adults: A Pilot Study on Spinal Stiffness Quantification with Ultrasound Imaging

Muscle stiffness in the spinal region is essential for maintaining spinal function, and might be related to multiple spinal musculoskeletal disorders. However, information on the distribution of muscle stiffness along the spine in different postures in large subject samples has been lacking, which merits further investigation. This study introduced a new protocol of measuring bilateral back muscle stiffness along the thoracic and lumbar spine (at T3, T7, T11, L1 & L4 levels) with both ultrasound shear-wave elastography (SWE) and tissue ultrasound palpation system (TUPS) in the lying and standing postures of 64 healthy adults. Good inter-/intra-reliability existed in the SWE and TUPS back muscle stiffness measurements (ICC ≥ 0.731, p < 0.05). Back muscle stiffness at the L4 level was found to be the largest in the thoracic and lumbar regions (p < 0.05). The back muscle stiffness of males was significantly larger than that of females in both lying and standing postures (p < 0.03). SWE stiffness was found to be significantly larger in standing posture than lying among subjects (p < 0.001). It is reliable to apply SWE and TUPS to measure back muscle stiffness. The reported data on healthy young adults in this study may also serve as normative reference data for future studies on patients with scoliosis, low back pain, etc.

Fiber Type-Specific Morphological and Cellular Changes of Paraspinal Muscles in Patients with Severe Adolescent Idiopathic Scoliosis

Background

Paraspinal muscle (PSM) has been suggested to have a role in adolescent idiopathic scoliosis (AIS). Few studies have investigated the fiber type-specific changes of PSM in detail.

Material/Methods

Bilateral multifidus muscles were harvested from the apical vertebra level (T7–T10) of 12 AIS patients and 6 control individuals. Immunohistological staining was performed to evaluate the muscle fiber type composition, fiber type-specific cross-sectional area (CSA), myonuclei density, and the total and activated satellite cell (SC) density. The correlations between these characteristics and curve initiation/severity were analyzed.

Results

In comparison with the PSM in convexity and the control group, PSM in concavity showed a significant reduction of CSA (concavity, 2601.1±574.1 μm²; convexity, 3732.1±545.1 μm²; control, 3426.5±248.4 μm²), myonuclei density (concavity, 2.0±0.3 myonuclei/fiber; convexity, 2.5±0.4 myonuclei/fiber; control, 2.2±0.2 myonuclei/fiber), and activated SC density (concavity, 0.7±0.4 cells/100 fibers; convexity, 1.5±0.7 cells/100 fibers; control, 1.2±0.3 cells/100 fibers) for fiber type I. The Cobb angle was positively correlated with the bilateral ratio of CSA (convexity/concavity) for both fiber types. The apical vertebral translation was positively correlated with bilateral difference of myonuclei density (type I), total SC density (types I and II), and activated SC density (type I).

Conclusions

The fiber type-specific pathological changes on the concave side seemed to be more severe. Some fiber type-specific characteristics (CSA, myonuclei density, total/activated SC density) were closely associated with curve severity. More attention should be paid to PSM physiotherapy treatment on the concave side.

Muscular Contribution to Adolescent Idiopathic Scoliosis from the Perspective of Stem Cell-Based Regenerative Medicine

Adolescent idiopathic scoliosis (AIS) is a relatively frequent disease within a range 0.5%-5.0% of population, with higher frequency in females. While a resultant spinal deformity is usually medically benign condition, it produces far going psychosocial consequences, which warrant attention. The etiology of AIS is unknown and current therapeutic approaches are symptomatic only, and frequently inconvenient or invasive. Muscular contribution to AIS is widely recognized, although it did not translate to clinical routine as yet. Muscle asymmetry has been documented by pathological examinations as well as systemic muscle disorders frequently leading to scoliosis. It has been also reported numerous genetic, metabolic and radiological alterations in patients with AIS, which are linked to muscular and neuromuscular aspects. Therefore, muscles might be considered an attractive and still insufficiently exploited therapeutic target for AIS. Stem cell-based regenerative medicine is rapidly gaining momentum based on the tremendous progress in understanding of developmental biology. It comes also with a toolbox of various stem cells such as satellite cells or mesenchymal stem cells, which could be transplanted; also, the knowledge acquired in research on regenerative medicine can be applied to manipulation of endogenous stem cells to obtain desired therapeutic goals. Importantly, paravertebral muscles are located relatively superficially; therefore, they can be an easy target for minimally invasive approaches to treatment of AIS. It comes in pair with a fast progress in image guidance, which allows for precise delivery of therapeutic agents, including stem cells to various organs such as brain, muscles, and others. Summing up, it seems that there is a link between AIS, muscles, and stem cells, which might be worth of further investigations with a long-term goal of setting foundations for eventual bench-to-bedside translation.

Asymmetric Expression of Wnt/B-catenin Pathway in AIS: Primary or Secondary to the Curve?

STUDY DESIGN

A prospective case-control study.

OBJECTIVES

To investigate whether the asymmetric changes are primary or secondary to spinal deformity.

SUMMARY OF BACKGROUND DATA

Previous study reported significantly decreased expression of Wnt/B-catenin pathway in adolescent idiopathic scoliosis (AIS) patients. To date, there is a lack of study investigating the relationship between differentially expressed Wnt/B-catenin pathway and the onset of the curve.

METHODS

Paraspinal muscles were collected from 40 female AIS patients and 20 age-matched congenital scoliosis (CS) patients. For CS patients, the samples were collected from the concave side and the convex side at the apical region. For AIS patients, the samples were collected from the proximal bilateral sides of the spine in addition to the apical region. qPCR and western blot were used to determine the expression of LBX1, B-catenin, and PAX3, all of which are regulated by the Wnt/B-catenin pathway. The relative mRNA expression level between the concave and the convex side was performed with the Student t test. Pearson correlation analysis was used to determine the relationship between gene expression and the curve magnitude.

RESULTS

AIS patients were found to have remarkably lower mRNA and protein expression of B-catenin, LBX1, and PAX3 in the concave side than in the convex side at the apical region. By contrast, at the proximal region, the mRNA expression of these three genes was comparable. Moreover, no significant difference regarding mRNA expression was found between the concave side and the convex side of CS patients. There was no remarkable correlation between the mRNA expression of the three genes and Cobb angle.

CONCLUSION

There exists remar kably asymmetric expression of Wnt/B-catenin pathway at the apical region of AIS, which however was comparable at the apical region of CS patients. Further investigation of Wnt/B-catenin signaling pathway may help reveal the etiology of AIS in future study.

LEVEL OF EVIDENCE

4.

Demonstration of asymmetric muscle perfusion of the back after exercise in patients with adolescent idiopathic scoliosis using intravoxel incoherent motion (IVIM) MRI

The purpose of this work was to quantify muscular perfusion patterns of back muscles after exercise in patients with adolescent idiopathic scoliosis (AIS) using intravoxel incoherent motion (IVIM) MR perfusion imaging. The paraspinal muscles of eight patients with AIS (Cobb angle 35 ± 10°, range [25-47°]) and nine healthy volunteers were scanned with a 1.5 T MRI, at rest and after performing a symmetric back muscle exercise on a Roman chair. An IVIM sequence with 16 b-values from 0 to 900 s/mm² was acquired, and the IVIM bi-exponential signal equation model was fitted in two steps. Perfusion asymmetries were evaluated using the blood flow related IVIM fD* parameter in regions of interest placed within the paraspinal muscles. Statistical significance was assessed using a Student t-test. The observed perfusion pattern after performing a Roman chair muscle exercise differed consistently in patients with AIS compared with healthy normal volunteers, and consisted of an asymmetrical increase in IVIM fD* [10^-3 mm² /s] above the lumbar convexity from 6.5 ± 5.8 to 28.8 ± 26.8 (p < 0.005), with no increase in the concavity (decrease from 6.5 ± 10.0 to 3.2 ± 1.5 (p = 0.19)), compared with a bilateral symmetric increase in the healthy volunteers (right, increase from 3.3 ± 2.1 to 10.1 ± 4.6 (p < 0.05); left, 6.7 ± 10.7 to 13.3 ± 7.0 (p < 0.05)). In conclusion, patients with AIS exhibit significant asymmetric muscle perfusion over the convexity of the scoliotic curvature after Roman chair exercise.

Exploring the Pathological Role of Collagen in Paravertebral Muscle in the Progression of Idiopathic Scoliosis

BACKGROUND

Paravertebral muscle (PVM) is considered as a contributing factor of idiopathic scoliosis (IS); collagen is crucial for maintaining the mechanical properties of PVM, but only a few researches have described this field. In this study, we observed the muscle stiffness of PVM and the curvature of the spine by adjusting the content of collagen in PVM of rats and explored the role of collagen in the progression of IS.

METHODS

32 female Sprague Dawley rats were randomly divided into four groups: neutralizing antibody (NA) group (group 1), normal control group (group 2), IS group (group 3), and IS with NA group (group 4). TGF-β1 NA was injected into PVM in group 1 and group 4, while Normal saline in group 2 and group 3. The Cobb angle and muscle stiffness were measured before and after injection; the rats were sacrificed at one week after injection, and performed histological, Western Blot, and qRT-PCR examinations.

RESULTS

X-rays showed that scoliosis occurred in group 1 and relieved in group 4. The stiffness of PVM was decreased significantly on the convex side in group 1, while on the concave side in group 4. The expression of TGF-β1 and COL1 on the concave side in IS rats (group 3) was significantly increased than that in normal rats (group 2), the concentration of COL1 and COL3 in group 3 was significantly higher than that in group 2, and the addition of TGF-β1 NA significantly downregulated COL1 and COL3 in group 1 and group 4. The concentration of COL1 in convex PVM was negatively related to Cobb angle in group 1 and group 2, and in concave PVM was positively related to Cobb angle in group 3 and group 4. However, no significant correlation was found between COL3 and Cobb angle in group 3 and group 4.

CONCLUSIONS

Asymmetric biomechanical characteristics of PVM was an important etiological factor of IS, which was directly correlated with collagen, it could be adjusted by local intramuscular injecting of TGF-β1 NA, and finally had an effect on the shape of the spine.

Magnetic Resonance Imaging-Based Morphological Change of Paraspinal Muscles in Girls With Adolescent Idiopathic Scoliosis

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

To investigate and compare any morphological differences in paraspinal muscles (PSM) between adolescent idiopathic scoliosis (AIS) patients (with severe or non-severe curves) and healthy controls.

SUMMARY OF BACKGROUND DATA

Several studies have reported abnormalities in biochemical, electromyographic activity, and histological changes of PSM in AIS. However, these studies only had qualitative data and without comparison with controls. Changes of muscle mass and mean density at the lumbar region have been described for scoliotic spines. All these findings suggested that imbalance of PSM in AIS could be a contributing factor to the development of severe scoliotic curve.

METHODS

T2-weighted MR images with multi-planar reconstruction were acquired in 41 Chinese AIS girls with a primary right-sided thoracic curve and 23 age-matched controls. In AIS, measurements of PSM were taken on both concavity and convexity of scoliosis starting from two vertebrae above and two below the apex. Morphological assessments of the multifidus (MF) and erector spinae (ES) muscles on both sides were made including signal intensity (SI) and fat deposition using manual tracing and thresholding technique, respectively. Same parameters were measured in controls at matched vertebrae. One-way analysis of variance (ANOVA) and Pearson correlation tests were used for statistical analysis.

RESULTS

Abnormalities were found at concavity of muscles between AIS and controls. Significantly higher SI and fatty components was observed in AIS at MF muscles on concavity than controls (P-value <0.001). Additionally, SI at MF muscles was significantly correlated with Cobb angle.

CONCLUSION

Increased SI and fatty components are asymmetrically present in PSM at apex in AIS. Our results showed higher intensity in PSM at concavity in AIS when compared with controls. There was a significant linear correlation between abnormal muscle signal and scoliotic curve. Above features are suggestive of altered muscle composition in concave PSM, possibly due to prolonged compression and reduced muscle activity of PSM caused by the spinal deformity.

LEVEL OF EVIDENCE

4.

Assessment of fatty infiltration of the multifidus muscle in patients with adolescent idiopathic scoliosis through evaluation by magnetic resonance imaging compared with histological analysis: a diagnostic accuracy study

To evaluate fat infiltration in the multifidus muscle close to the scoliotic curve as seen in MRI compared with the histological evaluation in patients with adolescent idiopathic scoliosis (AIS). The evaluation of fatty infiltration in the multifidus muscle of patients with AIS by MRI was compared with biopsy. Fatty infiltration was greater in concave side than in the convex side in both MRI (P=0.005) and biopsy evaluation (P=0.026). There was no correlation between the fatty infiltration findings evaluated through MRI and biopsy. The MRI measurements do not express accurately the tissue changes observed in the biopsy.

Functional variants of hepatocyte growth factor identified in patients with adolescent idiopathic scoliosis

The genetic etiology of adolescent idiopathic scoliosis (AIS) remains obscure. Whole-genome sequencing was performed in four members of one family. Then, we performed a rigorous computational analysis to determine the deleterious effects of the identified variants. Furthermore, the structural differences between the native hepatocyte growth factor (HGF) protein and a protein encoded by an HGF variant containing one mutation (p.T596M) were analyzed using molecular dynamic stimulation. A novel heterozygous mutation (p.T596M) within the HGF gene was identified and found to cosegregate with scoliosis phenotypes in three affected family members. Subsequent modeling and structure-based analyses supported the theory that this mutation is functionally deleterious. Functional analyses demonstrated that the HGF p.T596 M mutation changed the ability of the HGF protein to be secreted and impaired migration and invasion in HEK293T cells. Furthermore, an HGF knockdown zebrafish model exhibited a curly tailed phenotype. Mutation in HGF is associated with an autosomal dominant pattern of inheritance of AIS. This finding increases our understanding of the genetic heterogeneity of AIS.

Etiology of Adolescent Idiopathic Scoliosis: A Literature Review

Adolescent idiopathic scoliosis (AIS) is the peripubertal development of spinal curvature of a minimum of 10°. AIS is thought to be attributable to genetic factors, nutrition, early exposure to toxins, and hormonal dysregulation. Recent literature suggests these factors may compound to determine both disease onset and severity. Currently, treatment is limited to observation, bracing, and surgical intervention. Intervention is presently determined by severity and risk of curve progression. As they emerge, new therapies may target specific etiologies of AIS.

Reliability of the lateral abdominal muscle thickness measurements in idiopathic scoliosis patients

BACKGROUND

To date, the reliability of ultrasound imaging (US) measures of the abdominal muscle thickness in idiopathic scoliosis (IS) patients during early stages of adolescence has not been confirmed.

OBJECTIVE

To assess the intra-rater reliability of US measures of the thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) on convex and concave body sides in adolescents with IS.

DESIGN

One-way repeated-measures analysis of variance (ANOVA) and reliability study.

METHODS

Fifteen patients diagnosed IS were included between the ages of 9 and 14 years. Three repeated US measurements were recorded in the supine resting position over 2 sessions, 24 h apart.

RESULTS

By assessing the mean value from the first two measurements (ICC_3,2), the reliability was between .76 and .95 for all examined muscles on the convex and concave sides. The reliability for the mean values from three measurements (ICC_3,3) was between .81 and .96. The smallest detectable difference values for single measurements were twice as high on the convex side than on the concave side for all examined abdominal muscles.

CONCLUSION

US measurements of the thickness of the EO, IO, and TrA muscles in supine rest position in adolescent IS patients are reliable. In order to increase measurement reliability, and due to variability in reliability between concave and convex body side, we recommend using the mean of three consecutive measurements of the EO, IO, and TrA muscles for adolescents with IS.

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.

Electronic supplementary material

The online version of this article (10.1186/s10020-018-0049-y) contains supplementary material, which is available to authorized users.