Prognostic Value of Bone Mineral Density on Curve Progression: A Longitudinal Cohort Study of 513 Girls with Adolescent Idiopathic Scoliosis

Using ultrasound reflection coefficient index and other clinical parameters to predict the risk of progression in adolescents with idiopathic scoliosis (AIS)- a pilot study

PURPOSE

To determine the association of the ultrasound reflection coefficient index and other clinical parameters to predict curve progression in children with AIS.

METHODS

Sixty-six females (13.9 ± 1.5 years old) under observation with baseline Cobb angle (24.4 ± 10.4°) consented and participated. Besides the standard clinical procedures, all participants were scanned by an ultrasound (US) imager in a standing position. All participants had been followed, and the average follow-up visit was 7.5 ± 3.1 months. Five parameters were investigated, including the Cobb angle and the Risser sign measured from the radiographs, and the kyphotic angle (KA), the axial vertebral rotation (AVR), and the reflection coefficient (RC) index measured from the ultrasonographs. The curve was considered progressed when the Cobb angle measured on two consecutive radiographs was increased by more than 5°.

RESULTS

Among the 5 parameters, the KA, RC index, and Risser sign were found to be significantly associated with progression (p < 0.05). Children who had KA ≤ 38° and RC ≤ 0.06 showed higher chances of progression (62%) versus children with KA > 38° and RC > 0.06.

CONCLUSION

This pilot study showed that curve progression is associated with the Risser sign, KA, and RC index. Other parameters and a more extensive clinical study should be combined to develop a higher-accuracy prediction model.

A classification algorithm for prioritizing surgery in Pediatric patients with idiopathic scoliosis when Long Surgical delays are expected

PURPOSE

To identify the clinical phenotypes associated with the rate of progression while waiting for surgery and propose a classification scheme for identifying subgroups of patients to prioritize for surgery when long surgical delays are expected.

METHODS

We reviewed the clinical and radiographic data of a prospective cohort of patients scheduled for IS surgery from 2004 to 2020 with a minimum 1-year wait prior to surgery. Candidate predictors consisted of age, sex, Risser sign, menarchal status, angle of trunk rotation, scoliotic curve type, and main Cobb angle at baseline when scheduled for surgery. Univariate and Regression Tree analysis were performed to identify predictors associated with the annual curve progression rate in the main Cobb angle between baseline and surgery.

RESULTS

There were 214 patients (178 females) aged 15 ± 2 years, with a Risser sign 3.4 ± 1.6 and a main Cobb angle 55°±10° at baseline. The average wait prior to surgery was 1.3 ± 0.4 years. Only the Risser sign, menarchal status and sex were significantly associated with the annual progression rate. We have identified 3 clinically and significantly different groups of patients presenting slow (3 ± 4°/yr if Risser sign 3 to 5), moderate (8 ± 4°/yr if female with Risser sign 0 to 2 and post-menarchal), and fast (15 ± 10°/yr if Risser sign 0 to 2 and premenarchal or male) progression rates.

CONCLUSION

We present an evidence-based surgical prioritization algorithm for pediatric idiopathic scoliosis that can easily be implemented in clinical practice when long surgical delays are expected.

Exploring vertebral bone density changes in a trunk with adolescent idiopathic scoliosis: a mechanobiological modeling investigation of intact and unilaterally paralyzed muscles

This study aimed to elucidate the vertebral bone density variations associated with adolescent idiopathic scoliosis (AIS), specifically examining the impact of unilateral muscle paralysis using an integrated approach combining Frost's Mechanostat theory, a three-dimensional subject-specific finite element model and a musculoskeletal model of the L2 vertebra. The findings revealed a spectrum of bone density values ranging from 0.29 to 0.31 g/cm3, along with vertebral micro-strain levels spanning from 300 to 2200, consistent with existing literature. Furthermore, the ratio of maximum von Mises stress between the concave and convex side in the AIS model with intact muscles was approximately 1.08, which decreased by 4% due following unilateral paralysis of longissimus thoracis pars thoracic muscle. Overall, this investigation contributes to a deeper understanding of AIS biomechanics and lays the groundwork for future research endeavors aimed at optimizing clinical management approaches for individuals with this condition.

Distinguishing risk of curve progression in adolescent idiopathic scoliosis with bone microarchitecture phenotyping: a 6-year longitudinal study

Low bone mineral density and impaired bone quality have been shown to be important prognostic factors for curve progression in adolescent idiopathic scoliosis (AIS). There is no evidence-based integrative interpretation method to analyze high-resolution peripheral quantitative computed tomography (HR-pQCT) data in AIS. This study aimed to (1) utilize unsupervised machine learning to cluster bone microarchitecture phenotypes on HR-pQCT parameters in girls with AIS, (2) assess the phenotypes' risk of curve progression and progression to surgical threshold at skeletal maturity (primary cohort), and (3) investigate risk of curve progression in a separate cohort of girls with mild AIS whose curve severity did not reach bracing threshold at recruitment (secondary cohort). Patients were followed up prospectively for 6.22 ± 0.33 years in the primary cohort (n = 101). Three bone microarchitecture phenotypes were clustered by fuzzy C-means at time of peripubertal peak height velocity (PHV). Phenotype 1 had normal bone characteristics. Phenotype 2 was characterized by low bone volume and high cortical bone density, and phenotype 3 had low cortical and trabecular bone density and impaired trabecular microarchitecture. The difference in bone quality among the phenotypes was significant at peripubertal PHV and continued to skeletal maturity. Phenotype 3 had significantly increased risk of curve progression to surgical threshold at skeletal maturity (odd ratio [OR] = 4.88; 95% CI, 1.03-28.63). In the secondary cohort (n = 106), both phenotype 2 (adjusted OR = 5.39; 95% CI, 1.47-22.76) and phenotype 3 (adjusted OR = 3.67; 95% CI, 1.05-14.29) had increased risk of curve progression ≥6° with mean follow-up of 3.03 ± 0.16 years. In conclusion, 3 distinct bone microarchitecture phenotypes could be clustered by unsupervised machine learning on HR-pQCT-generated bone parameters at peripubertal PHV in AIS. The bone quality reflected by these phenotypes was found to have significant differentiating risk of curve progression and progression to surgical threshold at skeletal maturity in AIS.

Gut microbiota, inflammatory factors, and scoliosis: A Mendelian randomization study

Several studies have reported a potential association between the gut microbiota (GM) and scoliosis. However, the causal relationship between GM and scoliosis and the role of inflammatory factors (IFs) as mediators remain unclear. This study aimed to analyze the relationship between GM, IFs, and scoliosis. We investigated whether IFs act as mediators in pathways from the GM to scoliosis. Additionally, using reverse Mendelian randomization (MR) analysis, we further investigated the potential impact of genetic predisposition to scoliosis on the GM and IFs. In this study, we searched for publicly available genome-wide association study aggregate data and utilized the MR method to establish bidirectional causal relationships among 211 GM taxa, 91 IFs, and scoliosis. To ensure the reliability of our research findings, we employed 5 MR methods, with the inverse variance weighting approach serving as the primary statistical method, and assessed the robustness of the results through various sensitivity analyses. Additionally, we investigated whether IFs mediate pathways from GM to scoliosis. Three negative causal correlations were observed between the genetic predisposition to GM and scoliosis. Additionally, both positive and negative correlations were found between IFs and scoliosis, with 3 positive and 3 negative correlations observed. IFs do not appear to act as mediators in the pathway from GM to scoliosis. In conclusion, this study demonstrated a causal association between the GM, IFs, and scoliosis, indicating that IFs are not mediators in the pathway from the GM to scoliosis. These findings offer new insights into prevention and treatment strategies for scoliosis.

MRI-based vertebral bone quality score as a novel bone status marker of patients with adolescent idiopathic scoliosis

To investigate the application of MRI-based vertebral bone quality (VBQ) score in assessing bone mineral density (BMD) for patients with adolescent idiopathic scoliosis (AIS). We reviewed the data of AIS patients between January 2021 and October 2023 with MRI, whole-spine plain radiographs, quantitative computed tomography (QCT) and general information. VBQ score was calculated using T1-weighted MRI. Univariate analysis was applied to present the differences between variables of patients with normal BMD group (QCT Z-score > - 2.0) and low BMD group (QCT Z-score ≤ - 2.0). The correlation between VBQ score and QCT Z-score was analyzed with Pearson correlation test. A multivariate logistic regression model was used to determine the independent factors related to low BMD. Receiver operating characteristic curve (ROC) was drawn to analyze the diagnostic performance of VBQ score in distinguishing low BMD. A total of 136 AIS patients (mean age was 14.84 ± 2.10 years) were included, of which 41 had low BMD. The low BMD group had a significantly higher VBQ score than that in normal group (3.48 ± 0.85 vs. 2.62 ± 0.62, P < 0.001). The VBQ score was significantly negative correlated with QCT Z score (r =  - 0.454, P < 0.001). On multivariate analysis, VBQ score was independently associated with low BMD (OR: 4.134, 95% CI 2.136-8.000, P < 0.001). The area under the ROC curve indicated that the diagnostic accuracy of the VBQ score for predicting low BMD was 81%. A sensitivity of 65.9% with a specificity of 88.4% could be achieved for distinguishing low BMD by setting the VBQ score cutoff as 3.18. The novel VBQ score was a promising tool in distinguishing low BMD in patients with AIS and could be useful as opportunistic assessment for screening and complementary evaluation to QCT before surgery.

Potential Interaction between WNT16 and Vitamin D on Bone Qualities in Adolescent Idiopathic Scoliosis Patients and Healthy Controls

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that is associated with low bone mineral density (BMD). Vitamin D (Vit-D) supplementation has been suggested to improve BMD in AIS, and its outcomes may be related to genetic factors. The present study aimed to (a) investigate the synergistic effect between a low BMD-related gene (wingless-related integration site 16, WNT16) and two important Vit-D pathway genes (Vit-D receptor, VDR, and Vit-D binding protein, VDBP) on serum Vit-D and bone qualities in Chinese AIS patients and healthy adolescents, and (b) to further investigate the effect of ablating Wnt16 on the cortical bone quality and whether diets with different dosages of Vit-D would further influence bone quality during the rapid growth phase in mice in the absence of Wnt16. A total of 519 girls (318 AIS vs. 201 controls) were recruited, and three selected single-nucleotide polymorphisms (SNPs) (WNT16 rs3801387, VDBP rs2282679, and VDR rs2228570) were genotyped. The serum 25(OH)Vit-D level was significantly associated with VDBP rs2282679 alleles (OR = -4.844; 95% CI, -7.521 to -2.167, p < 0.001). Significant multi-locus models were identified by generalized multifactor dimensionality reduction (GMDR) analyses on the serum 25(OH)Vit-D level (p = 0.006) and trabecular area (p = 0.044). In the gene-edited animal study, Wnt16 global knockout (KO) and wildtype (WT) male mice were provided with different Vit-D diets (control chow (1000 IU/Kg) vs. Vit-D-deficient chow (Nil in Vit-D) vs. high-dose Vit-D chow (20,000 IU/Kg)) from 4 weeks to 10 weeks old. Wnt16 global KO mice had significantly lower serum 25(OH)Vit-D levels and higher liver Vdbp mRNA expression levels than WT mice. In addition, Wnt16 global KO mice showed a decrease in bone density, cortical thickness and cortical area compared with WT mice. Interestingly, high-dose Vit-D chow led to lower bone density, cortical thickness, and cortical area in WT mice, which were less obvious in Wnt16 global KO mice. In conclusion, WNT16 may regulate the serum 25(OH)Vit-D level and bone qualities, which might be associated with VDBP expression. Further investigations with a larger sample size and wider spectrum of scoliosis severity are required to validate our findings regarding the interaction between WNT16 and Vit-D status in patients with AIS.

Long-term changes in bone mineral density following adolescent idiopathic scoliosis surgery: a minimum 34-year follow-up

PURPOSE

To investigate longitudinal changes in bone mineral density (BMD) in middle-aged female patients who underwent spinal fusion for adolescent idiopathic scoliosis (AIS).

METHODS

The study subjects were 229 female patients who were diagnosed with AIS and underwent spinal fusion between 1968 and 1988. A two-step survey study was conducted on 19 female AIS patients. BMD, Z-scores, T-scores, and the prevalence of osteoporosis and osteopenia were compared between the initial (2014-2016) and second (2022) surveys. Correlations between the annual changes in Z-scores and T-scores with radiographic parameters, body mass index (BMI), and the number of remaining mobile discs were analyzed.

RESULTS

BMD decreased significantly from the initial (0.802 ± 0.120 g/cm2) to the second survey (0.631 ± 0.101 g/cm2; p < 0.001). Z-scores decreased from 0.12 ± 1.09 to - 0.14 ± 1.04, while T-scores decreased significantly from - 0.70 ± 1.07 to - 1.77 ± 1.11 (p < 0.001). The prevalence of osteopenia and osteoporosis increased significantly from 36.8% to 89.5% (p = 0.002), but the increase in osteoporosis alone was not statistically significant (5.3% to 26.3%; p = 0.180). Moderate negative correlations were found between annual changes in Z-scores and both main thoracic (MT) curve (r = - 0.539; p = 0.017) and lumbar curve (r = - 0.410; p = 0.081). The annual change in T-scores showed a moderate negative correlation with the MT curve (r = - 0.411; p = 0.081).

CONCLUSION

Significant reductions in BMD and an increased prevalence of osteopenia and osteoporosis were observed in middle-aged female AIS patients who had undergone spinal fusion. The decline in Z-scores in patients with AIS suggested that there was an accelerated loss of BMD compared with the general population. Larger residual curves could pose an added osteoporosis risk. Further research is needed to understand if the onset of osteoporosis in AIS patients is attributable to the condition itself or the surgical intervention.

Etiopathogenesis of adolescent idiopathic scoliosis (AIS): Role of genetic and environmental factors

Adolescent idiopathic scoliosis (AIS) has been known to be related closely to genetic factors. Higher prevalence of AIS among individuals with family history of scoliosis suggesting critical roles of genetic in the pathogenesis of AIS. However, evidence also suggested that environmental factors such as latitude and sun exposure also play a critical role in the pathogenesis of the disease. While genetic factors played an important role in the occurrence of AIS, environmental factors are more likely to affect the progression of the disease. Although the pathogenesis of AIS remains elusive, current knowledge suggests that genetic factors and its interaction with environmental factors are crucial in the development of the disease, explaining differences in clinical characteristics of AIS across the globe. The aim of this review is to summarize the current knowledge of genetic and environmental factors contributing to AIS and their interactions.

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.

BMP6 participates in the pathogenesis of adolescent idiopathic scoliosis by regulating osteopenia

Adolescent idiopathic scoliosis (AIS) is a complex disease characterized by three-dimensional structural deformities of the spine. Its pathogenesis is associated with osteopenia. Bone-marrow-derived mesenchymal stem cells (BMSCs) play an important role in bone metabolism. We detected 1919 differentially expressed mRNAs and 744 differentially expressed lncRNAs in BMSCs from seven patients with AIS and five patients without AIS via high-throughput sequencing. Multiple analyses identified bone morphogenetic protein-6 (BMP6) as a hub gene that regulates the abnormal osteogenic differentiation of BMSCs in AIS. BMP6 expression was found to be decreased in AIS and its knockdown in human BMSCs significantly altered the degree of osteogenic differentiation. Additionally, CAP1-217 has been shown to be a potential upstream regulatory molecule of BMP6. We showed that CAP1-217 knockdown downregulated the expression of BMP6 and the osteogenic differentiation of BMSCs. Simultaneously, knockout of BMP6 in zebrafish embryos significantly increased the deformity rate. The findings of this study suggest that BMP6 is a key gene that regulates the abnormal osteogenic differentiation of BMSCs in AIS via the CAP1-217/BMP6/RUNX2 axis.

Do Adolescent Idiopathic Scoliosis Patients With Vitamin D Deficiency Have Worse Spine Fusion Outcomes?

BACKGROUND

Prior research has shown that patients with adolescent idiopathic scoliosis (AIS) have a higher prevalence of vitamin D deficiency compared with healthy peers. In adult orthopaedic populations, vitamin D deficiency has been shown to be a risk factor for higher reported pain and lower function. We investigated whether there was an association between vitamin D levels and AIS patient-reported outcomes, as measured by the Scoliosis Research Society (SRS-30) questionnaire.

METHODS

This was a single-center, cross-sectional study. Postoperative AIS patients were prospectively recruited during routine follow-up visits, 2 to 10 years after spine fusion. Vitamin D levels were measured by serum 25-hydroxyvitamin D (ng/mL). Patients were categorized based on vitamin D level: deficient (<20 ng/mL), insufficient (20 to 29 ng/mL), or sufficient (≥30 ng/mL). The correlation between vitamin D levels and SRS-30 scores was analyzed using multivariable analysis and pair-wise comparisons using Tukey method.

RESULTS

Eighty-seven AIS patients (83% female) were enrolled who presented at median 3 years (interquartile range: 2 to 5 y; range: 2 to 10 y) after spine fusion. Age at time of surgery was mean 15 (SD±2) years. Major coronal curves were a mean of 57 (SD±8) degrees preoperatively and 18 (SD±7) degrees postoperatively. It was found that 30 (34%) of patients were vitamin D sufficient, 33 (38%) were insufficient, and 24 (28%) were deficient. Although there was no correlation between vitamin D level and Pain, Mental Health, or Satisfaction domains ( P >0.05), vitamin D-deficient patients were found to be younger ( P <0.001) and had lower SRS-30 function ( P =0.002), Self-image ( P <0.001), and total scores ( P =0.003).

CONCLUSIONS

AIS patients with vitamin D deficiency (<20 ng/mL) are more likely to be younger age at time of surgery, and report lower Function, Self-image, and Total SRS-30 scores postoperatively. Further work is needed to determine whether vitamin D supplementation alters curve progression and patient outcomes.

LEVEL OF EVIDENCE

Level II-prognostic study.

Risk factors associated with low bone mineral density in children with idiopathic scoliosis: a scoping review

BACKGROUND

Children with idiopathic scoliosis (IS) have a high risk of osteoporosis and IS with low bone mineral density (BMD) are susceptible to curve progression. This review aims to explore the risk factors of low BMD in children with IS.

METHODS

Studies were retrieved from 5 databases that were published up to January 2022. Search terms are keywords in titles or abstracts, including subject headings related to "Scoliosis", "Bone Mineral Density", and "Risk Factors". Observational studies on risk factors of low BMD in children with IS were enrolled in this review. The number of studies, sample size, outcome measures, research type, endocrine, and lifestyle-related factors, gene/signal pathway, and other contents were extracted for qualitative analysis.

RESULTS

A total of 56 studies were included in this scoping review. Thirty studies involved genetic factors that may affect BMD, including the Vitamin-D receptor gene, RANK/RANKL signal pathway, the function of mesenchymal stem cells, Runx2, Interleukin-6 (IL-6), and miR-145/β-catenin pathway. Eight studies mentioned the influence of endocrine factors on BMD, and the results showed that serum levels of IL-6, leptin and its metabolites, and ghrelin in children with IS were different from the age-matched controls. In addition, there were 18 articles on lifestyle-related factors related to low BMD in children with IS, consisting of physical activity, calcium intake, Vitamin D level, and body composition.

CONCLUSIONS

Genetic, endocrine, and lifestyle-related factors might relate to low BMD and even osteoporosis in IS. To prevent osteoporosis, the effectiveness of regular screening for low BMD risk factors in children with IS needs to be investigated. Additionally, clear risk factors suggest strategies for bone intervention. Future studies should consider the effectiveness of calcium and vitamin D supplements and physical activity in BMD improvement.

Associations of physical activity and screen time with adolescent idiopathic scoliosis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is the most common type of idiopathic scoliosis, affecting approximately 0.61%-6.15% adolescents worldwide. To date, the results on the relationship between moderate-to-vigorous physical activity (MVPA) and AIS were inconsistent, and the association between screen time (ST) and AIS remained unclear. This study aimed to describe MVPA and ST among adolescents, and to explore the independent and joint associations between PA, ST, and AIS.

METHODS

A frequency-matched case-control study based on the 2021 Chinese School-based Scoliosis Screening Program in Shenzhen city, south China, was conducted. The research involved 494 AIS patients (aged 9-17 years) and 994 sex- and age-matched healthy controls. MVPA and ST were measured using a self-administered questionnaire. Logistic regression models estimated associations between PA, ST, and AIS.

RESULTS

Compared to subjects meeting the recommended 60-min daily of MVPA, adolescents reporting daily MVPA time less than 60 min had 1.76 times higher odds of experiencing AIS (95% CI: 1.32-2.35) and adolescents reporting daily MVPA in inactive status had 2.14 times higher odds of experiencing AIS (95% CI: 1.51-3.03). Moreover, participants reporting ST for 2 hours or more had 3.40 times higher odds of AIS compared with those reporting ST less than 2 hours (95% CI: 2.35-4.93). When compared with the adolescents reporting both ST and MVPA meeting the guidelines recommended times (ST < 2 h and MVPA ≥ 60 min/day), those reporting both ST ≥ 2 h and MVPA in inactive status are 8.84 times more likely to develop AIS (95% CI: 3.99-19.61).

CONCLUSIONS

This study reported that the insufficient MVPA, especially MVPA in inactive status, and excessive ST were risk factors for AIS. Additionally, the joint effects of insufficient MVPA and excessive ST probably increase the risk of AIS.

Abnormal morphological features of osteocyte lacunae in adolescent idiopathic scoliosis: A large-scale assessment by ultra-high-resolution micro-computed tomography

AIM

Abnormal osteocyte lacunar morphology in adolescent idiopathic scoliosis (AIS) has been reported while the results were limited by the number of osteocyte lacunae being quantified. The present study aimed to validate previous findings through (a) comparing morphological features of osteocyte lacunae between AIS patients and controls in spine and ilium using a large-scale assessment, and (b) investigating whether there is an association between the acquired morphological features of osteocyte lacunae and disease severity in AIS.

METHOD

Trabecular bone tissue of the facet joint of human vertebrae on both concave and convex sides at the apex of the scoliotic curve were collected from 4 AIS and 5 congenital scoliosis (CS) patients, and also at the same anatomic site from 3 non-scoliosis (NS) subjects intraoperatively. Trabecular bone tissue from ilium was obtained from 12 AIS vs 9 NS subjects during surgery. Osteocyte lacunae were assessed using ultra-high-resolution micro-computed tomography. Clinical information such as age, body mass index (BMI) and radiological Cobb angle of the major curve were collected.

RESULTS

There was no significant difference between density of osteocyte lacuna and bone volume fraction (BV/TV) between groups. A total of 230,076 and 78,758 osteocyte lacunae from facet joints of apical vertebra of scoliotic curve and iliac bone were included in the analysis, respectively. In facet joint bone biopsies, lacunar stretch (Lc.St) was higher, and lacunar equancy (Lc.Eq), lacunar oblateness (Lc.Ob), and lacunar sphericity (Lc.Sr) were lower in AIS and CS groups when compared with NS group. CA side was associated with higher Lc.St when compared with CX side. In iliac bone biopsies, Lc.Ob was higher and lacunar surface area (Lc.S) was lower in AIS group than NS group. Median values of Lc.St, Lc.Eq and Lc.Sr were significantly associated with radiological Cobb angle with adjustment for age and BMI (R-squared: 0.576, 0.558 and 0.543, respectively).

CONCLUSIONS

This large-scale assessment of osteocyte lacunae confirms that AIS osteocyte lacunae are more oblate in iliac bone that is less influenced by asymmetric loading of the deformed spine than the vertebrae. Shape of osteocyte lacunae in iliac bone is associated with radiological Cobb angle of the major curve in AIS patients, suggesting the likelihood of systemic abnormal osteocyte morphology in AIS. Osteocyte lacunae from concave side of scoliotic curves were more stretched in both AIS and CS groups, which is likely secondary to asymmetric mechanical loading.

Deriving a Novel Score for the Stratification of Risk Progression in Early-onset Scoliosis: A Multicenter Initiative

STUDY DESIGN

This was a retrospective multicenter study.

OBJECTIVE

To develop a novel progression risk stratification scoring system for early-onset scoliosis.

SUMMARY OF BACKGROUND DATA

There is a lack of investigations into variables affecting the risk of curve progression in early-onset scoliosis, which prevents stratification. A novel risk score system is needed to help in progression risk estimation.

METHODS

A retrospective analysis was done at three centers, from 1995 to 2020. Scoliosis cases before the age of 10 years, were included. Medical identifier, date of birth, sex, primary diagnosis, curve type, date/modality of treatment, date of follow-up appointments, and Cobb angles, were collected. Five ranks were selected for stratification. Categories with the same ranks were discarded. Point scores started at 0, for the lowest risk, and ended at 4, for highest risk. Iterations of variable combinations were conducted and clinical relevance was determined by evaluating sensitivity, specificity, positive predictive value, and negative predictive value based on score ranges for low and high risk of progression.

RESULTS

A total of 476 (230 males, 246 females) early-onset scoliosis patients were collected. The average age at diagnosis was 4.8 years (SD±2.8 yr). The average follow-up duration was 9.3 years (SD±6.9 yr, range: 5 mo-38 yr). Appointments totaled 2911, giving 2182 observations for the analysis. Patient observations numbered: 800 (36.7%) ending in progression, 1265 (58.0%) for nonprogression, 117 (5.4%) for inadequate follow-up, and 368 (16.9%) for rapid progression. The risk scoring system contained four categories: etiology, age, curve magnitude, and curve type. Categorized point combinations totaled 755, giving 1975 iterations. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to be 85.8%, 96.5%, 89.7%, and 95.1%, respectively.

CONCLUSION

A novel progression risk score for early-onset scoliosis was derived. The system can reliably differentiate between low and high-risk cases in clinical settings. Further validation in other regions may be important for verifying clinical relevance.

LEVEL OF EVIDENCE

Level 3.

Hounsfield unit for assessing asymmetrical loss of vertebral bone mineral density and its correlation with curve severity in adolescent idiopathic scoliosis

Background

Low bone mass concomitantly occurs in patients with adolescent idiopathic scoliosis (AIS) and can persist until skeletal maturity. The purpose of this study was to assess the asymmetrical loss of vertebral bone mineral density (vBMD) and its correlation with curve severity in patients with AIS using Hounsfield unit (HU) values measured from computed tomography scans.

Methods

A total of 93 AIS patients were retrospectively recruited. The HU values of the vertebral body (VB-HU) and pedicle screw trajectory (PST-HU) were measured from four vertebrae above (Apex − 4) to four below (Apex + 4) the apical vertebra (Apex) of the major curve. The VB-HU and PST-HU at the upper end vertebra, Apex, and lower end vertebra within the concave and convex sides of the major and minor curves and stable vertebrae were obtained.

Results

A significant correlation was found between the Cobb angle and VB-HU at the periapical levels of the major curve. VB-HU and PST-HU at periapical levels were significantly greater within the concavity than the convexity of both major and minor curves. The asymmetric ratios of VB-HU and PST-HU were significantly correlated with the major curve Cobb angle, peaked at the apex, and gradually diminished from the apex to the end vertebrae. The asymmetrical loss of vBMD aggravated with the progression of curve severity, presenting as VB-HU, significantly decreased within the convexity and insignificantly decreased within the concavity of the major curve.

Conclusion

The asymmetrical loss of vBMD was associated with the progression of curve severity in AIS. For patients with severe AIS, the distraction of the pedicle screws at the concave side should be a priority in correcting the major curve, and supplemental anchors and larger-sized screws should be placed within the convex side around the apex of the major curve to reduce the risk of screw loosening after surgery.

Investigation of ultrasonic soft tissue-bone reflection coefficients correlating with curve severity in children with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional curvature of spine. Children with AIS and low bone quality have higher chance to get curve progression leading to bigger spinal curvature. In addition, bone quality affects acoustic impedance of bone, thus influencing the reflection coefficient of ultrasound signal from the soft tissue–bone interface. This study aimed to estimate the bone quality of AIS patients based on the reflection coefficients to determine the correlation of the bone quality with curve severity. A simple bone model was used to develop an equation to calculate the reflection coefficient value. Experiments were conducted on five different phantoms. Acrylic was used to design a vertebral shape to study the effect of surface roughness and inclination, including: smooth flat surface (SFS), smooth curved surface (SCS), rough curved surface (RCS), and the rough curved inclined surface (RCIS). A clinical study with 37 AIS patients were recruited. The estimated reflection coefficient values of plate phantoms agreed well with the predicted values and the maximum error was 6.7%. The reflection coefficients measured from the acrylic-water interface for the SFS, SCS, RCS, RCIS (3° and 5°) were 0.37, 0.33, 0.28, (0.23 and 0.12), respectively. The surface roughness and inclination increased the reflection loss. From the clinical data, the average reflection coefficients for children with AIS were 0.11 and 0.07 for the mild curve group and the moderate curve group, respectively. A moderate linear correlation was found between the reflection coefficients and curve severity (r2 = 0.3). Patients with lower bone quality have observed to have larger spinal curvature.

Upregulation of microRNA-96-5p is associated with adolescent idiopathic scoliosis and low bone mass phenotype

Bone densitometry revealed low bone mass in patients with adolescent idiopathic scoliosis (AIS) and its prognostic potential to predict curve progression. Recent studies showed differential circulating miRNAs in AIS but their diagnostic potential and links to low bone mass have not been well-documented. The present study aimed to compare miRNA profiles in bone tissues collected from AIS and non-scoliotic subjects, and to explore if the selected miRNA candidates could be useful diagnostic biomarkers for AIS. Microarray analysis identified miR-96-5p being the most upregulated among the candidates. miR-96-5p level was measured in plasma samples from 100 AIS and 52 healthy girls. Our results showed significantly higher plasma levels of miR-96-5p in AIS girls with an area under the curve (AUC) of 0.671 for diagnostic accuracy. A model that was composed of plasma miR-96-5p and patient-specific parameters (age, body weight and years since menarche) gave rise to an improved AUC of 0.752. Ingenuity Pathway Analysis (IPA) indicated functional links between bone metabolic pathways and miR-96-5p. In conclusion, differentially expressed miRNAs in AIS bone and plasma samples represented a new source of disease biomarkers and players in AIS etiopathogenesis, which required further validation study involving AIS patients of both genders with long-term follow-up.

Decreased cortical bone density and mechanical strength with associated elevated bone turnover markers at peri-pubertal peak height velocity: a cross-sectional and longitudinal cohort study of 396 girls with adolescent idiopathic scoliosis

Decreased cortical bone density and bone strength at peak height velocity (PHV) were noted in girls with adolescent idiopathic scoliosis (AIS). These findings could provide the link to the previously reported observation that low bone mineral density (BMD) could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

INTRODUCTION

As part of the studies related to aetiopathogenesis of AIS, we assessed bone qualities, bone mechanical strength and bone turnover markers (BTMs) focusing at the peri-pubertal period and PHV in AIS girls.

METHODS

396 AIS girls in two separate cohorts were studied. Skeletal maturity was assessed using the validated thumb ossification composite index (TOCI). Bone qualities and strength were evaluated with high-resolution peripheral quantitative computed tomography (HR-pQCT) and finite element analysis (FEA).

RESULTS

Cohort-A included 179 girls (11.95 ± 0.95 years old). Girls at TOCI-4 had numerically the highest height velocity (0.71 ± 0.24 cm/month) corresponding to the PHV. Subjects at TOCI-4 had lower cortical volumetric BMD (672.36 ± 39.07 mg/mm³), cortical thickness (0.68 ± 0.08 mm) and apparent modulus (1601.54 ± 243.75 N/mm²) than: (a) those at TOCI-1-3 (724.99 ± 32.09 mg/mm³ (p < 0.001), 0.79 ± 0.11 mm (p < 0.001) and 1910.88 ± 374.75 N/mm² (p < 0.001), respectively) and (b) those at TOCI-8 (732.28 ± 53.75 mg/mm³ (p < 0.001), 0.84 ± 0.14 mm (p < 0.001), 1889.11 ± 419.37 N/mm² (p < 0.001), respectively). Cohort-B included 217 girls (12.22 ± 0.89 years old). Subjects at TOCI-4 had higher levels of C-terminal telopeptide of type 1 collagen (1524.70 ± 271.10 pg/L) and procollagen type 1 N-terminal propeptide (941.12 ± 161.39 µg/L) than those at TOCI-8 (845.71 ± 478.55 pg/L (p < 0.001) and 370.08 ± 197.04 µg/L (p < 0.001), respectively).

CONCLUSION

AIS girls had decreased cortical bone density and bone mechanical strength with elevated BTMs at PHV. Coupling of PHV with decreased cortical and FEA parameters could provide the link to the previously reported observation that low BMD could contribute as one of the prognostic factors for curve progression that mostly occurs during PHV in AIS.

Six-Month Results on Treatment Adherence, Physical Activity, Spinal Appearance, Spinal Deformity, and Quality of Life in an Ongoing Randomised Trial on Conservative Treatment for Adolescent Idiopathic Scoliosis (CONTRAIS)

Adolescents with idiopathic scoliosis (AIS) often receive conservative treatments aiming to prevent progression of the spinal deformity during puberty. This study aimed to explore patient adherence and secondary outcomes during the first 6 months in an ongoing randomised controlled trial of three treatment interventions. Interventions consisted of physical activity combined with either hypercorrective Boston brace night shift (NB), scoliosis-specific exercise (SSE), or physical activity alone (PA). Measures at baseline and 6 months included angle of trunk rotation (ATR), Cobb angle, International Physical Activity Questionnaire short form (IPAQ-SF), pictorial Spinal Appearance Questionnaire (pSAQ), Scoliosis Research Society (SRS-22r), EuroQol 5-Dimensions Youth (EQ-5D-Y) and Visual Analogue Scale (EQ-VAS). Patient adherence, motivation, and capability in performing the intervention were reported at 6 months. The study included 135 patients (111 females) with AIS and >1-year estimated remaining growth, mean age 12.7 (1.4) years, and mean Cobb angle 31 (±5.3). At 6 months, the proportion of patients in the groups reporting high to very high adherence ranged between 72 and 95%, while motivation ranged between 65 and 92%, with the highest proportion seen in the NB group (p = 0.014, p= 0.002). IPAQ-SF displayed significant between group main effects regarding moderate activity (F = 5.7; p = 0.004; ηp2 = 0.10), with a medium-sized increase favouring the SSE group compared to NB. Walking showed significant between group main effects, as did metabolic equivalent (MET-min/week), with medium (F = 6.8, p = 0.002; ηp2 = 0.11, and large (F = 8.3, p = < 0.001, ηp2 = 0.14) increases, respectively, for the SSE and PA groups compared to NB. From baseline to 6 months, ATR showed significant between group medium-sized main effects (F = 1.2, p = 0.019, ηp2 = 0.007) favouring the NB group compared to PA, but not reaching a clinically relevant level. In conclusion, patients reported high adherence and motivation to treatment, especially in the NB group. Patients in the SSE and PA groups increased their physical activity levels without other clinically relevant differences between groups in other clinical measures or patient-reported outcomes. The results suggest that the prescribed treatments are viable first-step options during the first 6 months.

Effects of a Home-Based Exercise Intervention (E-Fit) on Bone Density, Muscle Function, and Quality of Life in Girls with Adolescent Idiopathic Scoliosis (AIS): A Pilot Randomized Controlled Trial

Background: Adolescent idiopathic scoliosis (AIS) patients have lower physical activity levels than normal adolescents, and there is an association with poorer bone and muscle health. This study evaluated the effects of a home-based exercise intervention (E-Fit) on bone mineral density (BMD), muscle function, and quality of life (QoL) in AIS-affected girls. Methods: A total of 40 AIS females aged 11 to 14 years were randomly assigned to the E-Fit or control group. The E-Fit group performed modified 7-min high-intensity interval training (HIIT) 5 days per week for 6 months. Outcome measures including BMD using dual-energy X-ray absorptiometry (DXA), muscle strength and endurance tests, physical activity levels, and QoL using self-reported questionnaires were assessed at baseline and at 6-month and 12-month follow-up. Results: In total, 14 patients in the E-Fit and 16 in the control group completed the study. The E-Fit group showed a marginally significant interaction effect in the whole body areal BMD at the 6- (p = 0.096) and 12-month follow-ups (p = 0.085). The left arm lean mass in the E-Fit group showed a statistically significant interaction effect between the 6- and 12-month follow-ups (p = 0.046). The E-Fit group showed improvements in physical activity participation, as measured by the Modified Baecke Questionnaire (MBQ), with a significant interaction effect in work index (p = 0.043), sport index (p = 0.050), and total score (p = 0.016) from baseline to the 12-month follow-up. Improvement on self-image were noted in E-Fit group across time. Conclusions: The present results provided some evidence to support the positive benefits of E-Fit for bone health and muscle function in AIS girls.

What Is New in Pediatric Bone Health

BACKGROUND

This review paper aims to report on the last 5 years of relevant research on pediatric bone health in regard to nutrition and obesity, ethnic disparities, common orthopaedic conditions, trauma, spine, and sports medicine.

METHODS

A search of the PubMed database was completed using the following terms: bone health, Vitamin D, pediatric, adolescent, sports medicine, fractures, spine, scoliosis, race, ethnicity, obesity, Slipped Capital Femoral Epiphysis, Osteogenesis Imperfecta, Duchenne's Muscular Dystrophy, neuromuscular, and cancer. Resultant papers were reviewed by study authors and determined to be of quality and relevance for description in this review. Papers from January 1, 2015 to August 31, 2020 were included.

RESULTS

A total of 85 papers were selected for review. General results include 7 key findings. (1) Obesity inhibits pediatric bone health with leptin playing a major role in the process. (2) Socioeconomic and demographic disparities have shown to have a direct influence on bone health. (3) Vitamin D deficiency has been linked to an increased fracture risk and severity in children. (4) Formal vitamin D monitoring can aid with patient compliance with treatment. (5) Patients with chronic medical conditions are impacted by low vitamin D and need ongoing monitoring of their bone health to decrease their fracture risk. (6) Vitamin D deficiency in pediatrics has been correlated to low back pain, spondylolysis, and adolescent idiopathic scoliosis. Osteopenic patients with AIS have an increased risk of curve progression requiring surgery. Before spine fusion, preoperative screening for vitamin D deficiency may reduce complications of fractures, insufficient tissue repair, loosening hardware, and postoperative back pain. (7) Increasing youth sports participation has resulted in increased bone health related injuries. However, improved understanding of Relative Energy Deficiency in Sport effects on bone health has recently occurred.

CONCLUSIONS

Increasing awareness of bone health issues in children will improve their recognition and treatment. Further research is needed on diagnosis, treatment, outcomes, and most importantly prevention of pediatric bone health diseases.

A Decade in Review after Idiopathic Scoliosis Was First Called a Complex Trait-A Tribute to the Late Dr. Yves Cotrel for His Support in Studies of Etiology of Scoliosis

Adolescent Idiopathic Scoliosis (AIS) is a prevalent and important spine disorder in the pediatric age group. An increased family tendency was observed for a long time, but the underlying genetic mechanism was uncertain. In 1999, Dr. Yves Cotrel founded the Cotrel Foundation in the Institut de France, which supported collaboration of international researchers to work together to better understand the etiology of AIS. This new concept of AIS as a complex trait evolved in this setting among researchers who joined the annual Cotrel meetings. It is now over a decade since the first proposal of the complex trait genetic model for AIS. Here, we review in detail the vast information about the genetic and environmental factors in AIS pathogenesis gathered to date. More importantly, new insights into AIS etiology were brought to us through new research data under the perspective of a complex trait. Hopefully, future research directions may lead to better management of AIS, which has a tremendous impact on affected adolescents in terms of both physical growth and psychological development.

Elucidating the inherent features of IS to better understand idiopathic scoliosis etiology and progression

Idiopathic Scoliosis (IS) is a relatively common condition and is estimated to affect as many as 3 % of youth aged 10-17 years (in the United States an estimated approximately 1.4 million otherwise healthy individuals). A clear understanding of the etiology will better direct optimization of evaluation, treatments and therapies, especially early treatments with less invasive methods. A mechanistic explanation of factors combining to initiate and then cause progression of this common condition-- in otherwise healthy pre-teenage and teenage patients--will be discussed. A recent well-designed structured systematic review states that 'strong evidence is lacking for a consistent pattern of occurrence and any abnormality', in other words there is no strong evidence for 'other associated diagnoses' in IS. And so, certain important inherent factors of IS merit greater discussion. Inherent, or intrinsic factors include: a natural susceptibility to develop a lateral and rotational deformity in the immature rapidly growing erect human spine, inherent torsion associated at the induction of deformity, biomechanics related to curve progression, and anthropology/bipedal gait. We know more today about factors related to the condition and its etiology than we have previously. Across multiple disciplines, a mechanistic approach to understanding the etiopathogenesis of IS, allows a reasonable 'theory' for IS etiology and its progression. We will discuss these inherent intrinsic factors in order to further add to our understanding of the theoretical etiopathogenesis. A better understanding of the etiology (and progression) may better direct ways to optimize evaluation, treatments and therapies, especially early treatments with less invasive methods.

Determining the correlation between Cobb angle severity and bone mineral density in women with adolescent idiopathic scoliosis

Objectives

To determine the correlation between Cobb angle severity and varying bone mineral density (BMD) and measure the prevalence of low BMD in women with adolescent idiopathic scoliosis (AIS) in KSA.

Methods

The sample included 54 women with AIS between 10 and 20 years of age. Data regarding Cobb angles and femoral and lumbar Z-scores according to dual-energy X-ray absorptiometry (DXA) scans performed between 2008 and 2018 were reviewed.

Results

Of the 54 patients recruited, 41 exhibited Cobb angles of 40–70° and 13 had Cobb angles >70°. The mean lumbar bone, right femur, and left femur BMDs were markedly higher in those with Cobb angles ≤70° compared with BMDs in those with Cobb angles >70°. Of the group with Cobb angles ≤70°, six (14.6%) and nine (22.0%) exhibited low BMD according to their lumbar and femoral Z-scores, respectively. Of the group with Cobb angles >70°, eight (61.5%) and nine (69.2%) exhibited low BMD according to their lumbar and femoral Z-scores, respectively.

Conclusions

Female AIS patients with greater higher Cobb angles exhibited a significantly higher frequency of low BMDs.

Scoliosis and Prognosis-a systematic review regarding patient-specific and radiological predictive factors for curve progression

INTRODUCTION

Idiopathic scoliosis, defined as a > 10° curvature of the spine in the frontal plane, is one of the most common spinal deformities. Age, initial curve magnitude and other parameters define whether a scoliotic deformity will progress or not. Still, their interactions and amounts of individual contribution are not fully elaborated and were the aim of this systematic review.

METHODS

A systematic literature search was conducted in the common databases using MESH terms, searching for predictive factors of curve progression in adolescent idiopathic scoliosis ("adolescent idiopathic scoliosis" OR "ais" OR "idiopathic scoliosis") AND ("predictive factors" OR "progression" OR "curve progression" OR "prediction" OR "prognosis"). The identified and analysed factors of each study were rated to design a top five scale of the most relevant factors.

RESULTS

Twenty-eight investigations with 8255 patients were identified by literature search. Patient-specific risk factors for curve progression from initial curve were age (at diagnosis < 13 years), family history, bone mineral status (< 110 mg/cm³ in quantitative CT) and height velocity (7-8 cm/year, peak 11.6 ± 1.4 years). Relevant radiological criteria indicating curve progression included skeletal maturity, marked by Risser stages (Risser < 1) or Sanders Maturity Scale (SMS < 5), the initial extent of the Cobb angle (> 25° progression) and curve location (thoracic single or double curve).

DISCUSSION

This systematic review summarised the current state of knowledge as the basis for creation of patient-specific algorithms regarding a risk calculation for a progressive scoliotic deformity. Curve magnitude is the most relevant predictive factor, followed by status of skeletal maturity and curve location.

Association of higher bone turnover with risk of curve progression in adolescent idiopathic scoliosis

OBJECTIVE

Emerging evidence suggest abnormal bone metabolism and defective bone qualities are associated to etipathogenesis of Adolescent Idiopathic Scoliosis (AIS). Systemic low bone mass is important prognosticator to predict risk of curve progression in AIS. The underlying mechanism is still unclear. We hypothesize that aberrant bone turnover correlates with bone qualities in AIS and associates to risk of curve progression.

SUBJECTS AND METHODS

Two cohorts were included in this study. The case-control study recruited 161 AIS girls and 161 ethnic/age-matched healthy girls. The longitudinal cohort recruited 128 AIS girls with two-year follow-up. Areal bone mineral density (BMD) at femoral necks were measured with dual-energy x-ray absorptiometry (DXA), and bone qualities of distal radius by high-resolution peripheral quantitative computed tomography (HR-pQCT). Time-lapse analysis of registered HR-pQCT images estimated local bone remodeling quantitatively. Serum levels of CTX and P1NP were measured with ELISA kits.

RESULTS

AIS presented significantly higher serum level of P1NP. In both AIS and control, the negative correlations were consistently observed between serum CTX/P1NP levels and most cortical bone quality parameters after adjustment to age. Significant correlation between serum bone turnover markers and trabecular bone parameters have been observed only in control. Progressive AIS has significant increase of serum P1NP level at first clinic visit. Time lapse register analysis showed high bone resorption and low net bone gain was associated with risk of progression in AIS.

CONCLUSIONS

Our study characterized AIS with higher serum bone turnover markers, which may contribute to defective bone qualities in AIS. For the first time, we showed that progressive AIS had higher systemic bone turnover markers level and local bone remodeling. This fresh evidence indicated association between disrupted bone turnover and risk of progression of AIS, which set the foundation of new prognostic method and of novel treatment target to curve progression. This study demonstrated the importance of bone metabolism in developing disease management of AIS to achieve goal of early prediction and non-surgical modulation.

Intervention versus Observation in Mild Idiopathic Scoliosis in Skeletally Immature Patients

Introduction:

Observation is the treatment of choice for idiopathic scoliosis with Cobb angles between 15 degrees - 20 degrees in growing children. This passive approach does not address the anxiety of the patient and the stress of the parents. In this paper, we attempt to identify skeletally immature patients with mild scoliosis curvatures that are more at risk of progression and propose possible intervention for this group of subjects.

Methods:

The literature was searched in Pubmed, and additional references were searched manually in the literature.

Results:

Many studies have shown that low serum 25[OH]D level, bone mineral density (BMD), and body mass index (BMI) are related to the curve severity or progression of the curve.

We suggest that skeletally immature patients (< Risser 2) with mild curves be divided into two groups, viz. Group O (observation) with a lower risk of progression, and Group I (intervention) with a higher risk of curvature progression. We propose early intervention for the latter group.

It is suggested that pre-menarcheal, skeletally immature patients with mild idiopathic scoliosis, and low vitamin D, BMD, and BMI should be treated. Also, asymmetric foot biomechanics should be addressed, although nutrition and foot orthoses are regarded to have no role in the management of idiopathic scoliosis. The outcome of early intervention may be utterly different from late treatment when the curvature becomes more structural, and the patient more skeletally mature.

Conclusion:

Research is required to prove if the intervention is clinically indicated.

Idiopathic Scoliosis as a Rotatory Decompensation of the Spine

Many years of dedicated research into the etiology of idiopathic scoliosis have not led to one unified theory. We propose that scoliosis is a mechanical, rotatory decompensation of the human spine that starts in the transverse, or horizontal, plane. The human spine is prone to this type of decompensation because of its unique and individually different, fully upright sagittal shape with some preexistent transverse plane rotation. Spinal stability depends on the integrity of a delicate system of stabilizers, in which intervertebral disc stiffness is crucial. There are two phases in life when important changes occur in the precarious balance between spinal loading and the disc's stabilizing properties: (i) during puberty, when loads and moment arms increase rapidly, while the disc's "anchor," the ring apophysis, matures from purely cartilaginous to mineralized to ultimately fused to the vertebral body, and (ii) in older age, when the torsional stiffness of the spinal segments decreases, due to disc degeneration and subsequent laxity of the fibers of the annulus fibrosus. During these crucial periods, transverse plane vertebral rotation can increase during a relatively brief window in time, either as adolescent idiopathic or degenerative de novo scoliosis. Much more is known of the biomechanical changes that occur during disc aging and degeneration than of the changing properties of the disc during maturation. © 2020 American Society for Bone and Mineral Research (ASBMR).

Current concepts in the diagnosis and management of adolescent idiopathic scoliosis

BACKGROUND

Adolescent Idiopathic Scoliosis (AIS) is a complex 3D structural disorder of the spine that has a significant impact on a person's physical and emotionalstatus. Thus, efforts have been made to identify the cause of the curvature and improve management outcomes.

AIM

This comprehensive review looks at the relevant literature surrounding the possible aetio-pathogenesis of AIS, its clinical features, investigations, surgicalmanagement options, and reported surgical outcomes in anterior spinal fusion, posterior spinal fusion or combined approach in the treatment of AIS.

Dysregulation of the ghrelin/RANKL/OPG pathway in bone mass is related to AIS osteopenia

BACKGROUND

Osteopenia has been well documented in adolescent idiopathic scoliosis (AIS), and ghrelin has been shown to have a positive effect on bone metabolism. However, the circulating level of ghrelin is increased in AIS osteopenia, and the relationship between ghrelin and low bone mass in AIS osteopenia remains unclear.

METHOD

A total of 563 AIS and 281 age-matched controls were recruited for this study. Anthropometry and bone mass were measured in all participants. Plasma ghrelin levels were determined by enzyme-linked immunosorbent assay (ELISA) in both AIS and control groups. An improved multiplex ligation detection reaction was performed to analyze single-nucleotide polymorphisms (SNPs). Facet joints were collected and subjected to immunohistochemistry; osteogenic gene and protein expression was also measured. Furthermore, primary cells were extracted from facet joints and bone marrow to observe the response to ghrelin stimulation.

RESULTS

The body mass index was lower and circulating ghrelin was markedly higher in the AIS osteopenia group than in the control group. No significant difference was observed in four ghrelin level-related SNPs between the AIS osteopenia and control groups. RNA and protein analyses revealed higher RANKL/OPG and lower runx2 levels in AIS cancellous bone. Compared with normal primary osteoblasts and BMSCs, AIS osteopenia primary cells were insensitive to the same ghrelin concentration gradient and showed lower osteogenic ability, increases in OPG and decreases in RANKL.

CONCLUSION

Our results indicate that high circulating ghrelin levels may not result from gene variations in AIS osteopenia. Dysregulation of the ghrelin/RANKL/OPG pathway may lead to decreased osteogenic ability of osteoblasts and BMSCs, which may be related to lower bone mass in AIS osteopenia.

Effect of the lumbar scoliosis on the results of dual-energy X-ray absorptiometry

One of the most common causes of lumbar scoliosis in adults is the decreased bone mineral density (BMD). The scoliosis in the lumbar spine has a known effect over the dual-energy X-ray absorptiometry (DXA) scan results. The objective of this study is to assess the influence of the lumbar scoliosis on the results of the DXA scan of the lumbar spine. 1019 women aged ≥40 years underwent a DXA scan of the spine. Age, weight, height, total BMD, total Tscore of the lumbar spine were recorded. The angle of the lumbar scoliosis (Cobb’s angle) was measured from the DXA scan image using a DICOM software. The incidence of lumbar scoliosis in the current study accounts to 12.3%. Women with scoliosis showed significantly higher incidence of discrepancy in BMD T-scores between the adjacent vertebrae by more than 1 SD compared to women without scoliosis, (p=0.046). DXA results of subjects with scoliosis require more detailed evaluation of the T-scores of each vertebra to make a prompt decision about the final diagnosis.

Persistent low-normal bone mineral density in adolescent idiopathic scoliosis with different curve severity: A longitudinal study from presentation to beyond skeletal maturity and peak bone mass

OBJECTIVES

Low bone mineral status has been reported in patients first presented with adolescent idiopathic scoliosis (AIS). We aimed to study whether low-normal bone mineral density (BMD) is persistent among AIS girls during puberty and at peak bone mass, and whether if such persistence is associated with curve severity and differed from healthy controls.

METHOD

This prospective longitudinal study comprised 550 AIS girls and 194 healthy control subjects followed from 1997 till 2016. Low-normal BMD was defined as z-standardized bone mineral density (z-BMD) of bilateral femoral neck ≤ -1. Markov Chain 2-stages analysis was conducted to investigate the low-normal BMD transition rate. Linear mixed-effects model and Bland-Altman plot were used to investigate whether low-normal BMD is persistent among a subgroup of AIS patients that reached peak bone mass.

RESULTS

The average z-BMD were comparable between AIS cohort and controls at 11 years old (-0.532 vs -0.602), but at 19 years old z-BMD worsened among AIS subjects (-0.860) while controls z-BMD improved (-0.455). During growth period until skeletal maturity, persistence of low-normal BMD was high in both cohorts (>80%) and the AIS group with severe curve presented 100% persistence. Subgroup analysis revealed that z-BMD of AIS patients at skeletal maturity and peak bone mass were highly correlated (r² = 0.905) and with good agreement.

CONCLUSION

AIS patients had poorer BMD that is associated with curve severity and more likely to persist beyond peripubertal period and at peak bone mass when compared to controls.

Assessment of Static Plantar Pressure, Stabilometry, Vitamin D and Bone Mineral Density in Female Adolescents with Moderate Idiopathic Scoliosis

(1) Background: Adolescent idiopathic scoliosis (AIS) can be associated with vitamin D deficiency and osteopenia. Plantar pressure and stabilometry offer important information about posture. The objectives of our study were to compare static plantar pressure and stabilometric parameters, serum 25-OH-vitamin D3 and calcium levels, and bone mineral densitometry expressed as z-score in patients with moderate AIS and healthy subjects. (2) Methods: 32 female adolescents (idiopathic S shaped moderate scoliosis, main lumbar curve) and 32 gender and age-matched controls performed: static plantar pressure, stabilometry, serum 25-OH-vitamin D3 and calcium levels, and dual X-ray absorptiometry scans of the spine. (3) Results: In scoliosis patients, significant differences were recorded between right and left foot for total foot, first and fifth metatarsal, and heel loadings. Stabilometry showed a poorer postural control when compared to healthy subjects (p < 0.001). Patients had significantly lower vitamin D, calcium levels, and z-scores. Lumbar Cobb angle was significantly correlated with the z-score (r = −0.39, p = 0.02), with right foot fifth metatarsal load (r = −0.35, p = 0.04), center of pressure CoP_x (r = −0.42, p = 0.01), CoP displacement (r = 0.35, p = 0.04) and 90% confidence ellipse area (r = −0.38, p = 0.03). (4) Conclusions: In our study including female adolescents with idiopathic S shaped moderate scoliosis, plantar pressure and stabilometric parameters were influenced by the main scoliotic curve.

Bone health in adolescents with idiopathic scoliosis

AIMS

Idiopathic scoliosis is the most common spinal deformity in adolescents and children. The aetiology of the disease remains unknown. Previous studies have shown a lower bone mineral density in individuals with idiopathic scoliosis, which may contribute to the causation. The aim of the present study was to compare bone health in adolescents with idiopathic scoliosis with controls.

METHODS

We included 78 adolescents with idiopathic scoliosis (57 female patients) at a mean age of 13.7 years (8.5 to 19.6) and 52 age- and sex-matched healthy controls (39 female patients) at a mean age of 13.8 years (9.1 to 17.6). Mean skeletal age, estimated according to the Tanner-Whitehouse 3 system (TW3), was 13.4 years (7.4 to 17.8) for those with idiopathic scoliosis, and 13.1 years (7.4 to 16.5) for the controls. Mean Cobb angle for those with idiopathic scoliosis was 29° (SD 11°). All individuals were scanned with dual energy x-ray absorptiometry (DXA) and peripheral quantitative CT (pQCT) of the left radius and tibia to assess bone density. Statistical analyses were performed with independent-samples t-test, the Mann-Whitney U test, and the chi-squared test.

RESULTS

Compared with controls, adolescents with idiopathic scoliosis had mean lower DXA values in the left femoral neck (0.94 g/cm² (SD 0.14) vs 1.00 g/cm² (SD 0.15)), left total hip (0.94 g/cm² (SD 0.14) vs 1.01 g/cm² (SD 0.17)), L1 to L4 (0.99 g/cm² (SD 0.15) vs 1.06 g/cm² (SD 0.17)) and distal radius (0.35 g/cm² (SD 0.07) vs 0.39 g/cm² (SD 0.08; all p ≤ 0.024), but not in the mid-radius (0.72 g/cm² vs 0.74 g/cm²; p = 0.198, independent t-test) and total body less head (1,559 g (SD 380) vs 1,649 g (SD 492; p = 0.0.247, independent t-test). Compared with controls, adolescents with idiopathic scoliosis had lower trabecular volume bone mineral density (BMD) on pQCT in the distal radius (184.7 mg/cm³ (SD 40.0) vs 201.7 mg/cm³ (SD 46.8); p = 0.029), but not in other parts of the radius or the tibia (p ≥ 0.062, Mann-Whitney U test).

CONCLUSION

In the present study, idiopathic scoliosis patients seemed to have lower BMD at central skeletal sites and less evident differences at peripheral skeletal sites when compared with controls. Cite this article: Bone Joint J 2020;102-B(2):268-272.

A validated composite model to predict risk of curve progression in adolescent idiopathic scoliosis

BACKGROUND

In adolescent idiopathic scoliosis (AIS), the continuous search for effective prognostication of significant curve progression at the initial clinical consultation to inform decision for timely treatment and to avoid unnecessary overtreatment remains a big challenge as evidence of the multifactorial etiopathogenic nature is increasingly reported. This study aimed to formulate a composite model composed of clinical parameters and circulating markers in the prediction of curve progression.

METHOD

This is a two-phase study consisting of an exploration cohort (120 AIS, mean Cobb angle of 25°± 8.5 at their first clinical visit) and a validation cohort (51 AIS, mean Cobb angle of 23° ± 5.0° at the first visit). Patients with AIS were followed-up for a minimum of six years to formulate a composite model for prediction. At the first visit, clinical parameters were collected from routine clinical practice, and circulating markers were assayed from blood.

FINDING

We constructed the composite predictive model for curve progression to severe Cobb angle > 40° with a high HR of 27.9 (95% CI of 6.55 to 119.16). The area under curve of the composite model is higher than that of individual parameters used in current clinical practice. The model was validated by an independent cohort and achieved a sensitivity of 72.7% and a specificity of 90%.

INTERPRETATION

This is the first study proposing and validating a prognostic composite model consisting of clinical and circulating parameters which could quantitatively evaluate the probability of curve progression to a severe curvature in AIS at the initial consultation. Further validation in clinic will facilitate application of composite model in assisting objective clinical decision.

Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a prevalent spinal deformity occurring during peripubertal growth period that affects 1-4% of adolescents globally without clear etiopathogenetic mechanism. Low bone mineral density is an independent and significant prognostic factor for curve progression. Currently, the cause underlying low bone mass in AIS remains elusive. Osteocytes play an important role in bone metabolism and mineral homeostasis, but its role in AIS has not been studied. In the present study, iliac bone tissues were harvested from 21 patients with AIS (mean age of 14.3 ± 2.20 yr old) with a mean Cobb angle of 55.6 ± 10.61° and 13 non-AIS controls (mean age of 16.5 ± 4.79 yr old) intraoperatively. Acid-etched scanning electron microscopy (SEM) images of AIS demonstrated abnormal osteocytes that were more rounded and cobblestone-like in shape and were aligned in irregular clusters with shorter and disorganized canaliculi. Further quantitative analysis with FITC-Imaris technique showed a significant reduction in the canalicular number and length as well as an increase in lacunar volume and area in AIS. SEM with energy-dispersive X-ray spectroscopy analysis demonstrated a lower calcium-to-phosphorus ratio at the perilacunar/canalicular region. Moreover, microindentaion results revealed lower values of Vickers hardness and elastic modulus in AIS when compared with controls. In addition, in the parallel study of 99 AIS (27 with severe Cobb angle of 65.8 ± 14.1° and 72 with mild Cobb angle of 26.6 ± 9.1°) with different curve severity, the serum osteocalcin level was found to be significantly and negatively associated with the Cobb angle. In summary, the findings in this series of studies demonstrated the potential link of abnormal osteocyte lacuno-canalicular network structure and function to the observed abnormal bone mineralization in AIS, which may shed light on etiopathogenesis of AIS.-Chen, H., Zhang, J., Wang, Y., Cheuk, K.-Y., Hung, A. L. H., Lam, T.-P., Qiu, Y., Feng, J. Q., Lee, W. Y. W., Cheng, J. C. Y. Abnormal lacuno-canalicular network and negative correlation between serum osteocalcin and Cobb angle indicate abnormal osteocyte function in adolescent idiopathic scoliosis.

Abnormal Osteoblastic Response to Leptin in Patients with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional structural deformity of the spine with unknown etiology. Although leptin has been postulated as one of the etiologic factors in AIS, its effects on osteoblastic activity remain unknown. Herein, we conducted this study to investigate whether there are abnormal functional responses to leptin and abnormal expression of leptin receptor in AIS osteoblasts. In vitro assays were performed with osteoblasts isolated from 12 severe AIS girls and 6 non-AIS controls. The osteoblasts were exposed to different concentrations of leptin (0, 10, 100, 1000 ng/mL). The effects of leptin on cell proliferation, differentiation and mineralization were determined. Protein expressions of leptin receptor (LEP-R) under basal and osteogenic conditions were also evaluated by Western blot. Our results showed that leptin significantly stimulated osteoblasts from non-AIS subjects to proliferate, differentiate and mineralized. However, in the AIS group, the stimulatory effects of leptin on cell proliferation, differentiation, and mineralization were not observed. In addition, no statistically significant difference in the expression of leptin receptor under both basal and osteogenic conditions was found between AIS and control group. In conclusion, these findings might help to explain the low bone mass and deranged bone quality that is clinically associated with AIS girls.

Bracing in Adolescent Idiopathic Scoliosis Trial (BrAIST): Development and Validation of a Prognostic Model in Untreated Adolescent Idiopathic Scoliosis Using the Simplified Skeletal Maturity System

STUDY DESIGN

Prognostic study and validation using prospective clinical trial data.

OBJECTIVE

To derive and validate a model predicting curve progression to ≥45° before skeletal maturity in untreated patients with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Studies have linked the natural history of AIS with characteristics such as sex, skeletal maturity, curve magnitude, and pattern. The Simplified Skeletal Maturity Scoring System may be of particular prognostic utility for the study of curve progression. The reliability of the system has been addressed; however, its value as a prognostic marker for the outcomes of AIS has not. The BrAIST trial followed a sample of untreated AIS patients from enrollment to skeletal maturity, providing a rare source of prospective data for prognostic modeling.

METHODS

The development sample included 115 untreated BrAIST participants. Logistic regression was used to predict curve progression to ≥45° (or surgery) before skeletal maturity. Predictors included the Cobb angle, age, sex, curve type, triradiate cartilage, and skeletal maturity stage (SMS). Internal and external validity was evaluated using jackknifed samples of the BrAIST data set and an independent cohort (n = 152). Indices of discrimination and calibration were estimated. A risk classification was created and the accuracy evaluated via the positive (PPV) and negative predictive values (NPV).

RESULTS

The final model included the SMS, Cobb angle, and curve type. The model demonstrated strong discrimination (c-statistics 0.89-0.91) and calibration in all data sets. The classification system resulted in PPVs of 0.71-0.72 and NPVs of 0.85-0.93.

CONCLUSIONS

This study provides the first rigorously validated model predicting a short-term outcome of untreated AIS. The resultant estimates can serve two important functions: 1) setting benchmarks for comparative effectiveness studies and 2) most importantly, providing clinicians and families with individual risk estimates to guide treatment decisions.

LEVEL OF EVIDENCE

Level 1, prognostic.

Long noncoding RNA lncAIS downregulation in mesenchymal stem cells is implicated in the pathogenesis of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a complex, three dimensional deformity of the spine that commonly occurs in pubescent girls. Abnormal osteogenic differentiation of mesenchymal stem cells (MSCs) is implicated in the pathogenesis of AIS. However, the biological roles of long noncoding RNAs (lncRNAs) in the regulation of osteogenic differentiation of MSCs are unknown. Through microarray analyses of bone marrow (BM) MSCs from healthy donors and AIS patients, we identified 1483 differentially expressed lncRNAs in AIS BM-MSCs. We defined a novel lncAIS (gene symbol: ENST00000453347) is dramatically downregulated in AIS BM-MSCs. In normal BM-MSCs, lncAIS interacts with NF90 to promote HOXD8 mRNA stability that enhances RUNX2 transcription in BM-MSCs, leading to osteogenic differentiation of normal BM-MSCs. By contrast, lncAIS downregualtion in AIS BM-MSCs cannot recruit NF90 and abrogates HOXD8 mRNA stability, which impedes RUNX2 transcription for osteogenic differentiation. Thereby lncAIS downregualtion in BM-MSCs suppresses osteogenic differentiation that is implicated in the pathogenesis of AIS.

Differential miRNAs profile and bioinformatics analyses in bone marrow mesenchymal stem cells from adolescent idiopathic scoliosis patients

BACKGROUND CONTEXT

Coexistence of abnormal skeletal growth and reduced bone mineral density in the context of adolescent idiopathic scoliosis (AIS) suggests disturbed bone metabolism existing in such patients. Our previous study suggested increased proliferation ability and decreased osteogenic differentiation ability of bone marrow mesenchymal stem cells (BM-MSCs) of AIS.

PURPOSE

To explore the differential miRNA expression profile, Go (gene ontology) terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways in BM-MSCs of AIS and non-AIS controls were conducted using microarray approach and bioinformatics analyses.

STUDY DESIGN

miRNA microarray approach and bioinformatics analysis.

METHODS

The differentially expressed miRNAs (DEMs) of BM-MSCs from AIS patients compared with those from healthy individuals were analyzed using a microarray analysis. Comprehensive bioinformatics analyses were then used to enrich datasets for gene ontology and pathway. Based on the interaction network analysis of DEMs contained in significant pathways, 12 potential crucial miRNAs were selected for validation by RT-PCR.

RESULTS

The study identified 54 previously unrecognized DEMs (12 upregulated, 42 downregulated) in BM-MSCs from AIS patients. These miRNAs are involved in multiple biological processes, including small GTPase-mediated signal transduction, DNA-dependent transcription, cytokinesis, cell adhesion, transmembrane transport, response to hypoxia, etc. Pathway analysis of these new identified miRNAs revealed dysregulated MAPK signaling pathway, PI3K-Akt signaling pathway, calcium signaling pathway, Notch signaling pathway, and ubiquitin-mediated proteolysis pathway, all of which have been reported to play important role in regulating the osteogenic or adipogenic differentiation of MSCs. Furthermore, interaction networks analysis indicated that seven most significant central miRNAs, including miR-17-5p, miR-106a-5p, miR-106b-5p, miR-16-5p, miR-93-5p, miR-15a-5p, and miR-181b-5p may play essential roles in AIS pathogenesis and accompanied osteopenia.

CONCLUSION

The current study reports the differential miRNAs expression profiles of BM-MSCs from AIS patients and related pathways for the first time. The identification of these candidate miRNAs provides a deep insight into the pathogenesis of AIS and the accompanying generalized osteopenia.

Bone measurements at multiple skeletal sites in adolescent idiopathic scoliosis-an in vivo correlation study using DXA, HR-pQCT and QCT

Significant correlations for bone mineral density and bone microstructure between spinal and non-spinal skeletal sites (distal radius and proximal femur) in adolescent idiopathic scoliosis (AIS) patients were observed, indicating that proximal femoral DXA and distal radial HR-pQCT could provide valid clinical assessments in patients with AIS.

PURPOSE

Low bone mass is an important feature of adolescent idiopathic scoliosis (AIS), which is a complex 3D spinal deformity that affects girls during puberty. However, no clinical imaging modality is suitable for regular monitoring on their spinal bone qualities in rapid growth period. Therefore, we investigated whether bone mineral density (BMD) and bone microstructure at non-spinal sites correlated with BMD and mechanical property in the spine in AIS patients.

METHODS

Thirty-two AIS girls (16.7 ± 3.5 years old with mean Cobb angle of 67 ± 11°) who underwent pre-operative spine CT examination for navigation surgery were recruited. Volumetric BMD (vBMD) of lumbar spine (LS) was measured by quantitative computed tomography (QCT), vBMD and bone microstructure of distal radius (DR) by high-resolution peripheral QCT (HR-pQCT) and areal BMDs of total hip (TH) and femoral necks (FN) by dual-energy X-ray absorptiometry (DXA). Biomechanical properties of the DR and LS were estimated by finite element analysis (FEA). Pearson correlation was performed to study the correlation between bone parameters at these three sites.

RESULTS

LS vBMD correlated significantly with both FN and TH aBMD (R = 0.663-0.725, both p < 0.01) and with DR microstructural parameters (R = 0.380-0.576, all p < 0.05). Mechanical properties of LS and DR were also correlated (R = 0.398, p = 0.039).

CONCLUSIONS

Bone measurement at proximal femur and distal radius could provide an additional predictive power in estimating the bone changes at spine, which is the primary site of deformity in AIS patients. Our result indicated that DXA and HR-pQCT could provide a valid surrogate for spine bone measurements in AIS patients.

Impact of Race Subgroups on the Assessment of Vitamin D Status in Adolescent Idiopathic Scoliosis

The authors' main objective was to demonstrate the confounding effect of combining subgroup data, specifically race, on the prevalence of vitamin D deficiency in adolescent idiopathic scoliosis (AIS). This was a retrospective chart review. Vitamin D deficiency was defined as 25-hydroxyvitamin D (25[OH]D) less than 20 ng/mL. Data were compared between white patients and black and Hispanic patients. Vitamin D status in girls with AIS was also compared with that in girls without AIS who had a history of fracture and with the medical literature to determine if deficiency in AIS was equal to or greater than other cohorts. Mean age was 13.9±2.3 years for the white girls with AIS (n=221) and 13.6±2.2 years for pooled non-whites (n=134). Significant racial differences were found that biased interpretation of the total pooled cohort. Mean 25(OH)D was 27.9±8.5 ng/mL for white girls with AIS vs 21.9±10.3 ng/mL for non-whites (P<.0001). Deficiency was present in 13.1% of white girls vs 47.8% of non-white girls (P<.0001). Compared with girls with fractures and with the published literature, the race-matched deficiency rates were not abnormally high in girls with AIS. Prevalence of deficiency was greater in non-whites with AIS than in whites. However, percent deficiency was not greater in girls with AIS than in race-matched cohorts without AIS. Without separating data by race, interpretation of vitamin D status can be confounded. [Orthopedics. 2019; 42(3):158-162.].

Replication Study for the Association of GWAS-associated Loci With Adolescent Idiopathic Scoliosis Susceptibility and Curve Progression in a Chinese Population

STUDY DESIGN

A genetic association (replication) study.

OBJECTIVE

The aim of this study was to replicate and further evaluate the association among seven genome-wide association studies (GWAS)-identified single nucleotide polymorphisms (SNPs) in Chinese girls with adolescent idiopathic scoliosis (AIS) with disease onset, curve types, and progression.

SUMMARY OF BACKGROUND DATA

AIS is the most common pediatric spinal deformity with a strong genetic predisposition. Recent GWAS identified 10 new disease predisposition loci for AIS.

METHODS

Three hundred nineteen female AIS patients with Cobb angle ≥ 10 and 201 healthy controls were studied for the association with disease onset. Seven GWAS-identified SNPs (rs11190870 in LBX1, rs12946942 in SOX9/KCNJ2, rs13398147 in PAX3/EPH4, rs241215 in AJAP1, rs3904778 in BNC2, rs6570507 in GPR126, and rs678741 in LBX1-AS1) were analyzed. In subgroup analysis, AIS patients were subdivided by curve types and disease progression to examine for genotype association.

RESULTS

We replicated the association with disease onset in four common SNPs rs11190870, rs3904778, rs6570507, and rs678741. In addition, rs1190870 and rs678741 remained significantly associated in the right thoracic curves only subgroup. However, no significant difference was observed with both clinical curve progression or Cobb angle.

CONCLUSION

This study replicated the associations of four GWAS-associated SNPs with occurrence of AIS in our Chinese population. However, none of these SNPs was associated with curve severity and progression. The results suggest that curve progression may be determined by environmental (nongenetic) factor, but further study with a larger sample size is required to address this issue.

LEVEL OF EVIDENCE

4.

Adiponectin regulates bone mass in AIS osteopenia via RANKL/OPG and IL6 pathway

BACKGROUND

Osteopenia have been well documented in adolescent idiopathic scoliosis (AIS). Adiponectin has been shown to be inversely proportional to body mass index and to affect bone metabolism. However, the circulating levels of adiponectin and the relationship between adiponectin and low bone mass in AIS remain unclear.

METHODS

A total of 563 AIS and 281 age-matched controls were recruited for this study. Anthropometry and bone mass were measured in all participants. Plasma adiponectin levels were determined by enzyme-linked immunosorbent assay (ELISA) in the AIS and control groups. An improved multiplex ligation detection reaction was performed to study on single nucleotide polymorphism. Facet joints were collected and used to measure the microstructure, the expression of RANKL, OPG, osteoblast-related genes, inflammatory factors, adiponectin and its receptors by qPCR, western blotting and immunohistochemistry. Furthermore, primary cells were extracted from facet joints to observe the reaction after adiponectin stimulation.

RESULTS

Compared with the controls, lower body mass index and a marked increase in circulating adiponectin were observed in AIS osteopenia (17.09 ± 1.09 kg/m² and 21.63 ± 10.30 mg/L). A significant difference in the presence of rs7639352
was detected in the AIS osteopenia, AIS normal bone mass and control groups. The T allele showed a significant higher proportion in AIS osteopenia than AIS normal bone mass and control groups (41.75% vs 31.3% vs 25.7%, p < 0.05). micro-CT demonstrated that the AIS convex side had a significant lower bone volume than concave side. RNA and protein analyses showed that in cancellous bone, higher RANKL/OPG and adipoR1 levels and lower runx2 levels were observed, and in cartilage, higher adipoR1 and IL6 levels were observed in AIS. Furthermore, convex side had higher RANKL/OPG, IL6 and adipoR1 than concave side. Compared with normal primary cells, convex side primary cells showed the most acute action, and concave side primary cells showed the second-most acute action when exposed under same adiponectin concentration gradient.

CONCLUSION

Our results indicated that high circulating adiponectin levels may result from gene variations in AIS osteopenia. Adiponectin has a negative effect on bone metabolism, and this negative effect might be mediated by the ADR1-RANKL/OPG and ADR1-IL6 pathways.

The Role of Vitamin D in the Pathogenesis of Adolescent Idiopathic Scoliosis

Several theories have been proposed to explain the etiology of adolescent idiopathic scoliosis (AIS) until present. However, limited data are available regarding the impact of vitamin D insufficiency or deficiency on scoliosis. Previous studies have shown that vitamin D deficiency and insufficiency are prevalent in adolescents, including AIS patients. A series of studies conducted in Hong Kong have shown that as many as 30% of these patients have osteopenia. The 25-hydroxyvitamin D3 level has been found to positively correlate with bone mineral density (BMD) in healthy adolescents and negatively with Cobb angle in AIS patients; therefore, vitamin D deficiency is believed to play a role in AIS pathogenesis. This study attempts to review the relevant literature on AIS etiology to examine the association of vitamin D and various current theories. Our review suggested that vitamin D deficiency is associated with several current etiological theories of AIS. We postulate that vitamin D deficiency and/or insufficiency affects AIS development by its effect on the regulation of fibrosis, postural control, and BMD. Subclinical deficiency of vitamin K2, a fat-soluble vitamin, is also prevalent in adolescents; therefore, it is possible that the high prevalence of vitamin D deficiency is related to decreased fat intake. Further studies are required to elucidate the possible role of vitamin D in the pathogenesis and clinical management of AIS.

[Correlation analysis between interleukin 6 polymorphism and adolescent idiopathic scoliosis susceptibility and bracing effectiveness]

Objective

To analyze the correlation between the polymorphism on interleukin 6 (IL-6) gene promoter region-174 locus and adolescent idiopathic scoliosis (AIS), including the susceptibility, the bracing effectiveness, and the possible mechanism.

Methods

The 182 AIS patients and 210 healthy controls who met the inclusion criteria between January 2013 and January 2016 were collected as research objects. The genotype of IL-6 gene promoter region-174 locus, the serum IL-6, the bone mineral density (BMD) of femoral neck and vertebrae (L _1-4), and the bone metabolism parameters, including bone alkaline phosphatase (BALP), bone gla protein (BGP), tartrate resistant acid phosphatase 5b (TRACP-5b), urine Ca, and urine Ca/Cr, were detected. All research objects were divided into the AIS group and the control group according to whether they had AIS, the GG, CG, CC groups according to their genotype, and progression-free group and progression group according to the therapeutic effectiveness of 1-year bracing treatment. Statistical analysis for the indexes were conducted respectively.

Results

There were significant differences in AIS history, BMD of femoral neck and lumbar vertebrae between the AIS group and control group ( P<0.05). According to the therapeutic effecitveness of 1-year bracing treatment, 182 AIS patients were divided into progression-free group in 110 cases and progression group in 72 cases. The results of single factor analysis showed that there were significant differences in the genotype and allele distribution of IL-6 gene promoter region-174 locus, BMD of femoral neck and lumbar vertebrae, IL-6, TRACP-5b, urine Ca, and urine Ca/Cr between the progression-free group and progression group ( P<0.05). The results of multivariable analysis showed that the BMD of lumbar vertebrae, TRACP-5b, and urine Ca were the influencing factors of bracing efficacy ( P<0.05). According to the results of genotype detection, all research objects were divided into GG group in 264 cases, CG group in 104 cases, and CC group in 24 cases. The IL-6, TRACP-5b, urine Ca, and urine Ca/Cr of GG type carriers were higher and BMD of femoral neck and lumbar vertebrae were lower when compared with the CG and CC type carriers ( P<0.05). The BMD of lumbar vertebrae of CG type carriers was lower than that of CC type carriers ( P<0.05).

Conclusion

The polymorphism of IL-6 genepromoter region-174 locus wasn't correlated with the AIS susceptibility, but it was correlated (not independently correlated) with the scoliosis progression under bracing treatment, and the risk for G-carried patients was higher. The mechanism may be that the polymorphism affected the IL-6 expression level and eventually affected the BMD of AIS patients through the bone metabolism.

Genetic and clinical characteristics of Filipino patients with Gaucher disease

Gaucher disease (GD) is a lysosomal storage disorder caused by the deficiency of the β-glucocerebrosidase enzyme due to disease causing mutations in the GBA1 (glucosidase beta acid) gene, leading to the abnormal accumulation of the lipid glucocerebroside in lysosomal macrophages. This is a review of the clinical features and molecular profiles of 14 Filipino patients with GD. Five patients presented with type 1 disease, two had type 2 GD and seven had type 3 GD. The age of onset for all types was between 1 and 2 years of age but there was a delay of 2.2 years from the time of symptom onset to confirmation of diagnosis. Hepatosplenomegaly, anemia and thrombocytopenia were present in most of the patients. Stunting was seen in 64.3% and bone abnormalities were present in 63.6%. The most common mutant allele detected in this cohort was L483P (previously L444P), followed by F252I, P358A and G241R. IVS2+1 G>A, N409S and G416S mutations were reported singularly. There were 3 patients who were found to have N131S mutations and one patient with D257V mutation, mutant alleles that have only been reported among the Filipinos to date. Except for N409S, the mutations found in this cohort were generally severe and were congruent with the severe phenotypes found in most patients. Of the 14 patients, only 6 were able to undergo enzyme replacement therapy which significantly improved the hematologic parameters and decreased the sizes of the liver and spleen but did not consistently improve the growth and skeletal abnormalities nor alleviate the neurological manifestations of our patients with GD. Improved monitoring through recommended modalities for assessments and tools for evaluation should be implemented in order to fully appreciate the severity of the disease and accuracy of the response to treatment.