Mechanism of right thoracic adolescent idiopathic scoliosis at risk for progression; a unifying pathway of development by normal growth and imbalance

The TLR-M-CSF axis is implicated in increased bone turnover and curve progression in adolescent idiopathic scoliosis

BACKGROUND

Facet joint osteoarthritis (OA) is prevalent in patients with adolescent idiopathic scoliosis (AIS). The most pronounced OA presents above and below the curve's apex where the intervertebral rotation is the greatest. This indicates that facet joint OA is implicated and potentially contributes to AIS progression. OA impacts both cartilage and bone and we have previously demonstrated an association between lower bone quality and more severe OA in AIS facet joints. This study aimed to further investigate the molecular mechanisms underlying cartilage-bone crosstalk in the facet joints of patients with AIS.

METHODS

Unbiased deep RNA sequencing was performed to compare gene expression in facet joint chondrocytes of age-matched AIS patients and non-scoliotic individuals. Differentially expressed genes of interest were validated through qPCR and ELISA in a larger sample cohort. Key regulatory pathways involved in cartilage-bone crosstalk were identified through bioinformatic analysis. Functional studies were conducted by treating chondrocytes with TLR2 and TLR4 agonists, collecting conditioned media, and administering it to an in vitro osteoclastogenesis model. The expression of M-CSF, a key regulatory factor influencing osteoclast proliferation, was measured in individual facet joint cartilage samples at different spinal levels and correlated with cartilage morphological grade and 3D structural parameters extracted from spine reconstruction.

RESULTS

One thousand four hundred twenty six upregulated genes were detected, and gene ontology analysis revealed a significant enrichment of the TLR pathway, and bone-regulating biological processes in AIS chondrocytes. TLR activation of AIS chondrocytes induced expression of bone-regulating factors, including M-CSF, a key regulator of osteoclast proliferation. Furthermore, secreted factors from AIS chondrocytes enhanced osteoclast proliferation and maturation, with a stronger effect observed following TLR pre-activation. Clinically, M-CSF expression was found to correlate strongly with increased OA severity and a greater degree of intervertebral axial rotation.

CONCLUSIONS

Together, our findings suggest that the TLR-M-CSF axis is implicated in osteoclastogenesis, resulting in increased bone turnover and may contribute to curve progression in AIS patients.

Genetic overlap between idiopathic scoliosis and schizophrenia in the general population

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) and schizophrenia (SCZ) are two distinct conditions with poorly understood aetiologies that both emerge in otherwise healthy young adolescents. One rare genetic condition associated with both phenotypic outcomes is the 22q11.2 deletion (22q11DS). This microdeletion, encompassing 47 genes, occurs in approximately 1 in 2,148 live births and confers a 20-fold higher risk for both AIS and schizophrenia compared to the general population. In the general population (non-22q11DS carriers), AIS and SCZ have also been reported to be related and genetic studies suggest the involvement of genetic variants implicated in the central nervous functioning. In this study, our objective was to further investigate genetic overlaps between these conditions in the general population. Specifically, we aimed to explore the role of genes within the 22q11.2 region, not only in terms of common variants but also their potential impact on gene networks and biopathways.

METHODS

We used summary statistics from three genome-wide association studies (GWAS): two focused on AIS (n = 11,210), and one on schizophrenia (n = 36,989). To explore potential overlaps between the two conditions, we conducted a comparative analysis on the significance-based ranked single nucleotide polymorphisms (SNPs) that are associated with both AIS and SCZ. Next, we employed in silico analyses to assess gene-networks enrichment for the most significant SNPs and investigate the contribution of genes within the 22q11.2 region. Post-hoc analysis was conducted to explore the biological pathways correlated with SNPs significantly associated with both AIS and SCZ.

RESULTS

The in silico analyses revealed a significant (adjusted-p < 0.05) genetic overlap between SCZ and both AIS cohorts. The top 3% of the most significant SNPs associated with both conditions exhibited a distinct enrichment cluster which is unlikely to be a result of chance (p < 3e-04). The gene-networks analyses showed a significant overlap of 26-41% with the ones involving genes in the 22q11DS region. However, there was no overlap between SNPs in this region and the most significant SNPs identified in the GWAS.

CONCLUSION

This study revealed compelling evidence that beyond the shared association with 22q11DS as a rare genetic variant, AIS and SCZ exhibit common genetic risk variants and an overlap of important genes. The gene networks enriched by the most significant SNPs for both conditions also intersect with the ones involving genes in the 22q11DS region. However, SNPs within this region were not overrepresented among the most significant SNPs from GWAS for both conditions. Notably, gene networks linked to the risk for both conditions suggest an involvement of biopathways related to cellular signaling and neuronal development.

Paraspinal muscles activities in S-shaped adolescent idiopathic scoliosis during physiotherapeutic scoliosis specific exercise: a case-control study

BACKGROUND

While Insights into the dynamics of the paraspinal muscles can contribute to more targeted interventions for individuals with adolescent idiopathic scoliosis (AIS), few studies have focused on changes in the paraspinal muscles of AIS during Physiotherapeutic Scoliosis-Specific Exercise (PSSE). Therefore, this study compared the differences in muscle activities between AIS and healthy subjects during PSSE, aiming to provide a scientific guidance of clinical treatment and daily life for AIS.

METHODS

Twelve S-shaped AIS and ten age-matched healthy controls participated. Five paired target paraspinal muscle groups (upper end vertebra, apex vertebra, lower end vertebra of the thoracic and apex vertebra, lower end vertebra of the lumbar) were assessed by surface electromyography (sEMG) during five postures: relaxed sitting, erect sitting, symmetrical pole-sitting correction and asymmetrical pole-sitting over-correction (1 and 2). Hold each posture for 20s and repeat 3 times to obtain sEMG data.

RESULTS

The results revealed that exercises effectively activated paraspinal muscles in AIS subjects, with a stronger activation observed during asymmetrical exercises (P < 0.05). Compared to healthy group, AIS subjects exhibited inhibited paraspinal muscle activity during relaxed sitting at the apex vertebra of thoracic and lumbar spine (P < 0.01). Additionally, in erect sitting, AIS subjects also showed inhibition of the paraspinal muscles at the apex of thoracic spine (P < 0.05). Furthermore, erect sitting failed to enhance symmetric muscle activation in S-shaped AIS.

CONCLUSIONS

These findings indicate that increasing the proportion and intensity of asymmetric exercises in PSSE treatments could enhance the activation and functional recovery of paraspinal muscles in AIS individuals. Furthermore, close monitoring of paraspinal muscle activity during rehabilitation is recommended to enable timely adjustments to the treatment regimen.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300075167, 28th of August, 2023.

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.

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.

Rare variant association analyses reveal the significant contribution of carbohydrate metabolic disturbance in severe adolescent idiopathic scoliosis

BACKGROUND

Adolescent idiopathic scoliosis (AIS), the predominant genetic-influenced scoliosis, results in spinal deformities without vertebral malformations. However, the molecular aetiology of AIS remains unclear.

METHODS

Using genome/exome sequencing, we studied 368 patients with severe AIS (Cobb angle >40°) and 3794 controls from a Han Chinese cohort. We performed gene-based and pathway-based weighted rare variant association tests to assess the mutational burden of genes and established biological pathways. Differential expression analysis of muscle tissues from 14 patients with AIS and 15 controls was served for validation.

RESULTS

SLC16A8, a lactate transporter linked to retinal glucose metabolism, was identified as a novel severe AIS-associated gene (p=3.08E-06, false discovery rate=0.009). Most AIS cases with deleterious SLC16A8 variants demonstrated early onset high myopia preceding scoliosis. Pathway-based burden test also revealed a significant enrichment in multiple carbohydrate metabolism pathways, especially galactose metabolism. Patients with deleterious variants in these genes demonstrated a significantly larger spinal curve. Genes related to catabolic processes and nutrient response showed divergent expression between AIS cases and controls, reinforcing our genomic findings.

CONCLUSION

This study uncovers the pivotal role of genetic variants in carbohydrate metabolism in the development of AIS, unveiling new insights into its aetiology and potential treatment.

Deletion of a conserved genomic region associated with adolescent idiopathic scoliosis leads to vertebral rotation in mice

Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis, in which spinal curvature develops in adolescence, and 90% of patients are female. Scoliosis is a debilitating disease that often requires bracing or surgery in severe cases. AIS affects 2%-5.2% of the population; however, the biological origin of the disease remains poorly understood. In this study, we aimed to determine the function of a highly conserved genomic region previously linked to AIS using a mouse model generated by CRISPR-CAS9 gene editing to knockout this area of the genome to understand better its contribution to AIS, which we named AIS_CRMΔ. We also investigated the upstream factors that regulate the activity of this enhancer in vivo, whether the spatial expression of the LBX1 protein would change with the loss of AIS-CRM function, and whether any phenotype would arise after deletion of this region. We found a significant increase in mRNA expression in the developing neural tube at E10.5, and E12.5, for not only Lbx1 but also other neighboring genes. Adult knockout mice showed vertebral rotation and proprioceptive deficits, also observed in human AIS patients. In conclusion, our study sheds light on the elusive biological origins of AIS, by targeting and investigating a highly conserved genomic region linked to AIS in humans. These findings provide valuable insights into the function of the investigated region and contribute to our understanding of the underlying causes of this debilitating disease.

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.

Is Lenke type V adolescent idiopathic scoliosis associated with different muscular morphometry?

The aim of the study was to evaluate the changes in psoas major (PM), erector spinae (ES), multifidus (MF), and rectus abdominis (RA) morphometry in Lenke type V adolescent idiopathic scoliosis (AIS) and control. Forty-two Lenke V AIS patients and 30 control were enrolled. The cross-sectional area (CSA) and CSA index (CI) of the PM, ES, MF, and RA at the T9-L5 levels were measured and compared between Lenke type V patients and control. The CI of the RA was significantly higher in the control group than the Lenke V group in multiple levels. On the other hand, there was no significant difference between patients with Lenke V AIS and control regarding the CI of the RA, ES, and PM. There was no significant difference between concave and convex sides of the Lenke V group regarding the CI of the RA, PM, MF, and ES. RA muscle mass is significantly affected in Lenke type 5 AIS regardless of convex or concave sides. This difference may be related to postural differences and back pain development in Lenke type 5 patients. Level of evidence: Level III.

Axial rotation and pain are associated with facet joint osteoarthritis in Adolescent Idiopathic Scoliosis

OBJECTIVE

Facet joints are crucial for spinal stability and develop premature osteoarthritis in patients with adolescent idiopathic scoliosis (AIS). Here, we evaluated the association between facet joint cartilage and subchondral bone homeostasis, perceived back pain and 3-dimensional spinal deformity to understand better the role of facet joint degeneration in AIS progression and pain.

METHOD

Cartilage and bone osteoarthritic states of AIS facet joint surgical samples were characterized using histological OARSI scoring, visual morphological grading and μCT analysis, respectively. Back pain was self-reported using a numerical rating scale and expressed relative to the location on the patient's back. The scoliotic curves from our patient cohort were digitally reconstructed using biplanar radiographs and the eOS system (EOS imaging). The deformity was then reduced to 3 intervertebral angles (coronal, sagittal and axial) for each pair of bilateral facet joints. Statistical associations between the intervertebral angles, osteoarthritis parameters and pain intensity were performed using the Spearman method and Friedman test.

RESULTS

Facet joint cartilage degeneration was associated with decreased subchondral bone volume and quality. Most importantly, asymmetrical, and overall degeneration of facet joints was strongly correlated to intervertebral axial rotation. Additionally, kyphotic intervertebral segments in the sagittal plane were good predictors of increased facet joint degeneration and back pain.

CONCLUSION

Facet joint degeneration is associated with axial deformity, kyphotic intervertebral angle and back pain intensity in AIS. These results suggest that facet joints are important features to consider for rotational instability in AIS spines and related disease progression and perceived back pain.

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.

Analysis of the prevalence of asymmetry and muscle tone disorders in the first year of life among youth with idiopathic scoliosis: A retrospective case-control study

BACKGROUND

Not much is known about developmental motor disorders in the first year of life of children diagnosed with idiopathic scoliosis (IS).

OBJECTIVE

This study aimed to compare the occurrence of asymmetry or muscle tone disorders in the first year of life in adolescents with IS and their healthy counterparts.

METHODS

The parents of adolescents with IS and without scoliosis completed a survey on the occurrence of asymmetry, abnormal muscle tone, and physiotherapy in their children in the first year of life. Pearson's chi square test and Cramer's coefficient were used.

RESULTS

The final analysis included 527 surveys completed by parents of adolescents with idiopathic scoliosis (150) and without scoliosis (377). A significantly higher frequency of asymmetry (p= 0.001) and muscle tone disorders (p= 0.001) was noted in adolescents with idiopathic scoliosis. The results also revealed a significant association between scoliosis and asymmetry (p= 0.001), as well as muscle tone (p= 0.001).

CONCLUSIONS

Developmental asymmetry or improper muscle tone in the first year of life could be considered a potential factor in the development of scoliosis; however, this hypothesis should be confirmed in future studies. Infants diagnosed with developmental disorders require systematic observation.

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.

Evaluation of Brace Treatment Using the Soft Brace Spinaposture: A Four-Years Follow-Up

The braces of today are constructed to correct the frontal plane deformity of idiopathic adolescent scoliosis (AIS). The Spinaposture brace© (Spinaposture Aps, Copenhagen, Denmark) is a soft-fabric brace for AIS and is designed to enhance rotational axial stability by inducing a sagittal plane kyphotic correction. This prospective observational study evaluated the brace in fifteen patients with AIS. The initial average CA was 16.8° (SD: 2.8). They were followed prospectively every 3 to 6 months during their brace usage until skeletal maturity of 25 months and at long-term follow-up of 44 months. In- and out-of-brace radiographs were performed in six subjects at inclusion. This resulted in an immediate in-brace correction of 25.3 percent in CA (14.3°→10.8°) and induced a kyphotic effect of 14.9 percent (40.8°→47.9°). The average in-brace improvement at first follow-up was 4.5° in CA, and the CA at skeletal maturity was 11° (SD: 7.4°) and long-term 12.0° (SD: 6.8°). In conclusion, the Spinaposture brace© had an immediate in-brace deformity correction and a thoracic kyphotic effect. At skeletal maturity, the deformities improved more than expected when compared to that of the natural history/observation and similar to that of other soft braces. No long-term deformity progression was seen. To substantiate these findings, stronger designed studies with additional subjects are needed.

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.

Functional Electrical Stimulation (FES) and the Effect on Equine Multifidi Asymmetry

Asymmetry of the multifidi has been correlated with scoliosis and back pain in humans and has been investigated as a factor in equine back pain as well. The purpose of this study was to determine if FES would affect the symmetry of equine thoracolumbar multifidi when compared to controls. Twelve horses received 24 FES treatments bilaterally over the thoracolumbar region for 8 weeks. Twelve additional control horses received no FES treatments. Ultrasonographic measurements of the cross-sectional area (CSA) of the multifidi of the treatment horses at seven thoracolumbar levels were compared to determine the change in left and right asymmetry post-FES. The same measurements during the same period were also taken in the control group. All measurements were blinded for evaluation. Statistical significance was assessed utilizing two-sided, matched-pairs t-tests, and Welch's (unequal variances) t-test (alpha = 0.05). Multiple comparisons were accounted for using the Sidak correction. A significant improvement in multifidi asymmetry was observed, post-FES, at all seven thoracolumbar levels, with no evidence of asymmetry improvement in the control group. The difference between mean improvements of the treatment and control groups was statistically significant (P < .001). FES significantly improved the symmetry of equine multifidi, and evidence was provided for the effectiveness of FES at each of seven thoracolumbar levels. The improvement in symmetry appeared to result from increases, decreases, and maintenance of the CSA of the left and right multifidi in various combinations. The FES protocol used in this study has the potential to improve spinal function and assist in reducing back pain in horses.

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.

The effects of rotation on radiological parameters in the spine

BACKGROUND

Vertebral rotation in straight spines or in spines with small scoliosis may potentially affect measurement of radiological parameters in both the frontal and sagittal plane. This is important, since it could lead to potential misdiagnosis of scoliosis and other clinical consequences, and until now, this has not been examined.

PURPOSE

To examine the effect of axial vertebral rotation of the spine on measurement of common radiological parameters.

MATERIAL AND METHODS

Reconstructions from computed tomography scans of 40 consecutive included and anonymized patients with straight spines or small scoliosis. Fourteen sagittal and coronal reconstructions covering the whole pelvis and spine were executed. Radiographic parameters in both the frontal and sagittal plane were measured blinded and separately by three doctors. These parameters were evaluated for inter-rater reliability using intraclass correlation coefficient and mixed model analysis for the effects of rotation. The parameters were also analyzed sub-stratified according to "Lenke's classification" and 15 sub-categories of thoracic and lumbar Cobb's angle (CA).

RESULTS

Vertebral rotation in general does not have any significant effects in both the frontal and sagittal plane. However, there are significant effects on CA and spinopelvic radiologic parameters in extreme rotation or for larger scoliosis. Inter-rater reliability was very good to good.

CONCLUSION

In conclusion, axial spinal rotation does not influence common radiological parameters in the frontal and sagittal plane, except in cases of extreme rotation or large scoliosis for selected parameters; thus, this does not lead to potential misinterpretation in scoliosis diagnosis, treatment, or research.

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.

Cobb Angle Reduction in a Nearly Skeletally Mature Adolescent (Risser 4) After Pattern-Specific Scoliosis Rehabilitation (PSSR)

Introduction

It has long been said that exercise-based rehabilitation for scoliosis is ineffective, however, these reports studied general exercises. This case report is a prospective one-year follow-up of a nearly skeletally mature adolescent female (Risser 4) with idiopathic scoliosis treated with Pattern-Specific-Scoliosis Rehabilitation (PSSR).

Methods

The 15-year old patient recommended for surgery (initial Cobb angle of 45°) completed a 16-hour scoliosis-specific back school (according to Schroth Best Practice^®), over the course of five weeks. She continued with her program at home, and followed up with the lead author after 6 months and 1 year.

Results

The patient achieved a 13° reduction in her primary thoracic Cobb angle. Postural improvement and reduction in trunk rotation (ATR) was also achieved (-4° in the thoracic spine, and -5° in the lumbar spine).

Conclusion

Pattern-specific scoliosis rehabilitation (PSSR) works to reduce the asymmetrical load caused by scoliosis. PSSR is effective in stabilizing Cobb angle, and can, in some cases, reduce Cobb angle in adolescents. Patients recommended for surgery may be candidates for conservative treatment. This case suggests that the practice of discontinuing conservative treatment at Risser stage 4 should be re-evaluated.

The role of the paravertebral muscles in adolescent idiopathic scoliosis evaluated by temporary paralysis

Background

Muscle imbalance has been suggested as implicated in the pathology of adolescent idiopathic scoliosis (AIS). The specific “pathomechanic” role of the paravertebral muscles as being scoliogenic (inducing scoliosis) or counteracting scoliosis in the initial development and maintenance of this spinal deformity has yet to be clarified in humans. In the present study, we investigated the radiographic changes of temporal paralysis using botulinum toxin A as localized injection therapy (ITB) in the psoas major muscle in AIS patients.

Methods

Nine patients with AIS were injected one time with ITB using ultrasonic and EMG guidance in the selected spine muscles. Radiographic and clinical examinations were performed before and 6 weeks after the injection. Primary outcome parameters of radiological changes were analyzed using Wilcoxon signed-rank test and binomial test, and secondary outcome parameters of short- and long-term clinical effects were obtained.

Results

Significant radiological corrective changes were seen in the frontal plane in the thoracic and lumbar spine as well as significant derotational corrective change in the lumbar spine according to Cobb’s angle measurements and to Nash and Moe’s classification, respectively. No serious adverse events were detected at follow-up.

Conclusions

In conclusion, this study demonstrated that the psoas major muscle do play a role into the pathology in adolescent idiopathic scoliosis by maintaining the curvature of the lumbar spine and thoracic spine.

Trial registration

EudraCT number 2008-004584-19

An immediate effect of PNF specific mobilization on the angle of trunk rotation and the Trunk-Pelvis-Hip Angle range of motion in adolescent girls with double idiopathic scoliosis-a pilot study

Background

Impairment of spine rotation is a key concept in several theories explaining the pathogenesis and progression of scoliosis. In previous studies, a more limited range of motion in scoliotic girls compared to their non-scoliotic peers was noted. The Trunk-Pelvis-Hip Angle measurement is a test used to assess the range of motion in the trunk-pelvis-hip complex in the transverse plane. The aim of this study was to assess an immediate effect of Proprioceptive Neuromuscular Facilitation specific mobilization (mPNF) on the angle of trunk rotation and Trunk-Pelvis-Hip Angle range of motion in adolescent girls with double scoliosis.

Methods

The study was conducted on 83 girls aged 10 to 17 years (mean 13.7 ± 1.9) with double idiopathic scoliosis consisting of a right-sided thoracic curve (mean 25.1° ± 13.9°) and a left-sided thoracolumbar or lumbar curve (mean 20.8° ± 11.4°). The angle of trunk rotation and Trunk-Pelvis-Hip Angle were measured at baseline and after PNF mobilization. Bilateral lower limb patterns of Proprioceptive Neuromuscular Facilitation were used in combination with the “contract–relax” technique and stimulation of asymmetrical breathing. In the statistical analysis, the SAS rel. 13.2 software was used. Preliminary statistical analysis was performed using descriptive statistics. According to Shapiro-Wilk criterion of normality, the Wilcoxon test was used to compare paired samples. Next, the data was analyzed using multivariate GLM models.

Results

In adolescent girls with double scoliosis, significant differences between the left and right side of the body concerning the Trunk-Pelvis-Hip Angle ranges were noted. A single, unilateral PNF mobilization significantly decreased the angle of trunk rotation in the thoracic (p < 0.001) and lumbar spine (p < 0.001). Unilateral PNF mobilization also increased the Trunk-Pelvis-Hip Angle ranges on the left (p < 0.001) and right (p < 0.001) side significantly.

Conclusions

Unilateral PNF mobilization led to a decrease in the angle of trunk rotation, improvement in the range of motion, and the symmetry of mobility in the transverse plane in the trunk-pelvis-hip complex in adolescent girls with double idiopathic scoliosis. The effects should be treated only as immediate. Further studies are required to determine long-term effects of PNF mobilization on the spinal alignment.

Trial registration

ISRCTN11750900.

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

Background

Several studies have described the differences in electromyographic activity and histological changes of paravertebral muscles in patients with adolescent idiopathic scoliosis (AIS). However, there is little knowledge about the muscle volumetric and fatty infiltration imbalance of patients with AIS.

Material/Methods

Thirty-four patients with AIS were evaluated with standardized anteroposterior (AP) and lateral standing films for the location and direction of the apex of scoliosis, coronal Cobb angle, apex vertebra translation, and thoracic kyphosis; and with magnetic resonance imaging (MRI) scan of the spine at the level of T4–L1. The muscle volume and fatty infiltration rate of bilateral deep paravertebral muscles at the level of upper end, apex, and lower end vertebra were measured.

Results

All patients had major thoracic curve with apex of curves on the right side. The muscle volume on the convex side was larger relative to the concave side at the three levels, while the fatty infiltration rate was significantly higher on the concave side. The difference index of the muscle volume was significantly larger at the apex vertebra level than at the upper end vertebra level (p=0.002) or lower end vertebra level (p<0.001). The difference index of muscle volume correlated with apex vertebra translation (r=−0.749, p=0.032), and the difference index of fatty involution correlated with apex vertebra translation (r=0.727, p=0.041) and Cobb angle (r=0.866, p=0.005).

Conclusions

Our findings demonstrated significant imbalance of muscle volume and fatty infiltration in deep paravertebral muscles of AIS patients. Moreover, these changes affected different vertebra levels, with the most imbalance of muscle volume at the apex vertebra. We interpreted this as morphological changes corresponding with known altered muscle function of AIS.

Adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common form of structural spinal deformities that have a radiological lateral Cobb angle - a measure of spinal curvature - of ≥10(°). AIS affects between 1% and 4% of adolescents in the early stages of puberty and is more common in young women than in young men. The condition occurs in otherwise healthy individuals and currently has no recognizable cause. In the past few decades, considerable progress has been made towards understanding the clinical patterns and the three-dimensional pathoanatomy of AIS. Advances in biomechanics and technology and their clinical application, supported by limited evidence-based research, have led to improvements in the safety and outcomes of surgical and non-surgical treatments. However, the definite aetiology and aetiopathogenetic mechanisms that underlie AIS are still unclear. Thus, at present, both the prevention of AIS and the treatment of its direct underlying cause are not possible.