Potential genetic markers predicting the outcome of brace treatment in patients with adolescent idiopathic scoliosis

Genetics and pathogenesis of scoliosis

Background

Scoliosis is defined as a lateral spine curvature of at least 10° with vertebral rotation, as seen on a posterior-anterior radiograph, often accompanied by reduced thoracic kyphosis. Scoliosis affects all age groups: idiopathic scoliosis is the most common spinal disorder in children and adolescents, while adult degenerative scoliosis typically affects individuals over fifty. In the United States, approximately 3 million new cases of scoliosis are diagnosed annually, with a predicted increase in part due to global aging. Despite its prevalence, the etiopathogenesis of scoliosis remains unclear.

Methods

This comprehensive review analyzes the literature on the etiopathogenetic evidence for both idiopathic and adult degenerative scoliosis. PubMed and Google Scholar databases were searched for studies on the genetic factors and etiopathogenetic mechanisms of scoliosis development and progression, with the search limited to articles in English.

Results

For idiopathic scoliosis, genetic factors are categorized into three groups: genes associated with susceptibility, disease progression, and both. We identify gene groups related to different biological processes and explore multifaceted pathogenesis of idiopathic scoliosis, including evolutionary adaptations to bipedalism and developmental and homeostatic spinal aberrations. For adult degenerative scoliosis, we segregate genetic and pathogenic evidence into categories of angiogenesis and inflammation, extracellular matrix degradation, neural associations, and hormonal influences. Finally, we compare findings in idiopathic scoliosis and adult degenerative scoliosis, discuss current limitations in scoliosis research, propose a new model for scoliosis etiopathogenesis, and highlight promising areas for future studies.

Conclusions

Scoliosis is a complex, multifaceted disease with largely enigmatic origins and mechanisms of progression, keeping it under continuous scientific scrutiny.

Curve Progression After the Termination of Bracing for Adolescent Idiopathic Scoliosis: Usefulness of Combining the Proximal Femur Maturity Index (PFMI) and Risser Staging

Background The brace therapy for adolescent idiopathic scoliosis (AIS) typically ends upon the end of growth. However, determining the timing of growth cessation can be challenging. The purpose of this study was to evaluate the utility of the proximal femur maturity index (PFMI), which can be assessed simultaneously with Risser staging without requiring additional radiation exposure, in determining the appropriate timing to terminate bracing. To achieve this, we investigated the relationship between skeletal maturity at the end of bracing, post-bracing curve progression, and height growth in patients who had been successfully treated with a brace. Methods Between April 2010 and March 2021, a total of 84 female patients with AIS who started bracing at our hospital with an initial Cobb angle of 20-40 degrees were included. All patients were followed for at least one year after brace termination. Height and radiographic parameters (Risser staging, PFMI, Cobb angle) were retrospectively collected. Results At the end of the bracing period, patients were categorized into Risser stage 4 (85.7%) and 5 (14.3%). By the last follow-up, patients with Risser stage 4 experienced an average main curve progression of 1.8°, whereas those with Risser stage 5 had an average progression of -0.3° (P = 0.03). Patients with Risser stage 4 were further divided into PFMI grade 5 (59.7%) and 6 (40.3%). Significant curve progression was observed in patients with PFMI grade 5 (average: 3.0°) compared to grade 6 (average: -0.6°) (P < 0.0001). The mean height growth was 1.9 cm/year for PFMI grade 5, and 0.3 cm/year for grade 6, with significant differences between these groups (P < 0.001). Conclusions PFMI allowed further categorization within Risser stage 4: PFMI grade 5 indicated remaining growth potential and risk of postbracing curve progression, whereas grade 6 indicated growth cessation. The combined use of Risser staging and PFMI, both evaluable through the same whole-spine radiograph, may provide a more accurate prediction of growth cessation.

Epigenetic and Genetic Factors Related to Curve Progression in Adolescent Idiopathic Scoliosis: A Systematic Scoping Review of the Current Literature

Adolescent idiopathic scoliosis (AIS) is a progressive deformity of the spine. Scoliotic curves progress until skeletal maturity leading, in rare cases, to a severe deformity. While the Cobb angle is a straightforward tool in initial curve magnitude measurement, assessing the risk of curve progression at the time of diagnosis may be more challenging. Epigenetic and genetic markers are potential prognostic tools to predict curve progression. The aim of this study is to review the available literature regarding the epigenetic and genetic factors associated with the risk of AIS curve progression. This review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out in January 2022. Only peer-reviewed articles were considered for inclusion. Forty studies were included; fifteen genes were reported as having SNPs with significant association with progressive AIS, but none showed sufficient power to sustain clinical applications. In contrast, nine studies reporting epigenetic modifications showed promising results in terms of reliable markers. Prognostic testing for AIS has the potential to significantly modify disease management. Most recent evidence suggests epigenetics as a more promising field for the identification of factors associated with AIS progression, offering a rationale for further investigation in this field.

Coronal deformity angular ratio as a predictive factor for in-brace curve correction and long-term outcome of brace treatment in adolescents with idiopathic scoliosis

PURPOSE

To investigate the relationship between coronal deformity angular ratio (C-DAR) and in-brace correction (IBC) and their role in predicting the long-term bracing outcome in adolescents with idiopathic scoliosis (AIS).

METHODS

In this retrospective multicenter study, the patient's sex, age, primary curve Cobb angle (at initiation of brace treatment, best in-brace, before spinal fusion, and final follow-up), curve pattern, duration of brace treatment, brace type, and C-DAR at initiation of bracing were recorded. The C-DAR values were classified as < 5, 5 ≤ to ≤ 6, and > 6. The IBC values were classified as ≥ 50%, 40% ≤ to ≤ 49%, and < 40%. We classified the patients into two groups of success and failure according to the Cobb angle at the final follow-up.

RESULTS

A total of 164 patients (25 boys and 119 girls) were included. Bracing was successful in 60.4% of them. There was a significant association between C-DAR and bracing outcome (p < 0.0001). 63.9% of the patients with C-DAR < 5 had an IBC ≥ 50%. However, when C-DAR was 5 ≤ to ≤ 6 and > 6, 29.2% and 16.9% of the patients had an IBC of ≥ 50%, respectively. For patients with IBC ≥ 50%, the success rate of bracing was 89.2%. Results of logistic regression analysis revealed that the strongest predictor for brace treatment outcome was the C-DAR, with an odds ratio of 2.11.

CONCLUSION

C-DAR may be used as a predictive factor for the long-term outcome of brace treatment in AIS.

LEVEL OF EVIDENCE

IV.

Predictive value of single-nucleotide polymorphisms in curve progression of adolescent idiopathic scoliosis

PURPOSE

Genetic diagnosis is a promising approach because several single-nucleotide polymorphisms (SNPs) associated with adolescent idiopathic scoliosis (AIS) progression have been reported. We review the predictive value of SNPs in curve progression of adolescent idiopathic scoliosis.

METHODS

We reviewed DNA-based prognostic testing to predict curve progression. Then, the multiple polymorphisms in loci related to AIS progression were also reviewed, and we elucidated the predictive value of SNPs from four functional perspectives, including endocrine metabolism, neuromuscular system, cartilage and extracellular matrix, enzymes, and cytokines.

RESULTS

The ScoliScores were less successful predictors than expected, and the weak power of predictive SNPs might account for its failure. Susceptibility loci in ESR1, ESR2, GPER, and IGF1, which related to endocrine metabolism, have been reported to predict AIS progression. Neuromuscular imbalance might be a potential mechanism of scoliosis, and SNPs in LBX1, NTF3, and SOCS3 have been reported to predict the curve progression of AIS. Susceptibility loci in SOX9, MATN1, AJAP1, MMP9, and TIMP2, which are related to cartilage and extracellular matrix, are also potentially related to AIS progression. Enzymes and cytokines play essential roles in regulating bone metabolism and embryonic development. SNPs in BNC2, SLC39A8, TGFB1, IL-6, IL-17RC, and CHD7 were suggested as predictive loci for AIS curve progression.

CONCLUSIONS

Many promising SNPs have been identified to predict the curve progression of AIS. However, conflicting results from replication studies and different ethnic groups hamper their reliability. Convincing SNPs from multiethnic populations and functional verification are needed.

Initial In-Brace Correction: Can the Evaluation of Cobb Angle Be the Only Parameter Predictive of the Outcome of Brace Treatment in Patients with Adolescent Idiopathic Scoliosis?

Background: Patients with a better initial in-brace correction could show a higher probability of a successful outcome. However, no one has investigated whether parameters can affect the outcomes. The aim of this retrospective study was to evaluate if the initial correction rate (ICR) could be predictive of the bracing outcome and to determine the role of some mechanical and biological parameters in ICR. Methods: The study population comprised 449 patients who met the inclusion criteria. Curve correction > 10° Cobb defines brace treatment success. Success and failure groups were compared in terms of the Risser sign, initial Cobb angle, initial Perdriolle value and ICR. Results: ICR significantly correlates with initial Perdriolle. The success group had a significantly lower value of Pedriolle and initial Cobb angles, Risser sign and ICR than the failure group. The ICR and lower Risser were significantly associated with the brace treatment outcome. This seems particularly suitable for positivity prediction (Predicting value VP+: 87%). Conclusions: This study confirms that immediate in-brace correction can foretell the brace treatment outcome. Patients with a low Risser sign and a high rate of in-brace correction showed a bracing success of 87%. A correlation between rotation and in-brace correction confirms that rotation is among the parameters that influence the deformed spine reaction to corrective actions the most.

Association study of single nucleotide polymorphism in tryptophan hydroxylase 1 gene with adolescent idiopathic scoliosis: A meta-analysis

BACKGROUND

Adolescent idiopathic scoliosis is a common spinal deformity among children and adolescents worldwide with its etiology uncertain. Over a decade, a single nucleotide polymorphism rs10488682 in tryptophan hydroxylase 1 (TPH1) gene has been investigated in several association studies. We perform this study to summarize the current evidence of TPH1 rs10488682 polymorphisms and adolescent idiopathic scoliosis (AIS).

METHODS

Six databases were systematically searched: PubMed, Embase, Cochrane Library, Web of Science, Chinese Biomedical Literature, and Wanfang database. Eligible case-control studies related to TPH1 and AIS were selected. Reference lists of them were reviewed for more available studies. Two authors independently screened and evaluated the literature and extracted data. The odds ratios and 95% confidence intervals were derived in association tests. Subgroup analysis was conducted by ethnicity. Sensitivity analysis was performed to examine the stability of the overall results.

RESULTS

A total of 1006 cases and 1557 controls in 3 independent studies were included for meta-analysis. Statistical significance was discovered in heterozygote model (AT vs AA: OR = 1.741, 95%Cl = 1.100-2.753, P = .018 < .05, I2 = 0%), recessive model (AA vs AT + TT: OR = 0.640, 95%Cl = 0.414-0.990, P = .045 < .05, I2 = 0%) and over-dominant model (AT vs AA + TT: OR = 1.366, 95%Cl = 1.115-1.673, P = .003 < .05, I2 = 84.7%) in overall populations. Similar associations were also found in the Caucasian population. No significant associations were found in other genotypic comparisons and allelic comparisons.

CONCLUSIONS

Statistically significant correlations were discovered between the TPH1 rs10488682 polymorphisms and AIS. Heterozygous AT genotype seems to be risky with an over-dominant effect. Ethnicity appears to modify the disease association.

REGISTRATION

Not applicable.

From genetics to epigenetics to unravel the etiology of adolescent idiopathic scoliosis

Scoliosis is defined as the three-dimensional (3D) structural deformity of the spine with a radiological lateral Cobb angle (a measure of spinal curvature) of ≥10° that can be caused by congenital, developmental or degenerative problems. However, those cases whose etiology is still unknown, and affect healthy children and adolescents during growth, are the commonest form of spinal deformity, known as adolescent idiopathic scoliosis (AIS). In AIS management, early diagnosis and the accurate prediction of curve progression are most important because they can decrease negative long-term effects of AIS treatment, such as unnecessary bracing, frequent exposure to radiation, as well as saving the high costs of AIS treatment. Despite efforts made to identify a method or technique capable of predicting AIS progression, this challenge still remains unresolved. Genetics and epigenetics, and the application of machine learning and artificial intelligence technologies, open up new avenues to not only clarify AIS etiology, but to also identify potential biomarkers that can substantially improve the clinical management of these patients. This review presents the most relevant biomarkers to help explain the etiopathogenesis of AIS and provide new potential biomarkers to be validated in large clinical trials so they can be finally implemented into clinical settings.

Predictors for long-term curve progression after Boston brace treatment of idiopathic scoliosis

BACKGROUND

Identifying factors that predict successful bracing in patients with idiopathic scoliosis may help planning treatment.

AIM

To assess predictors for long-term curve progression and health-related quality of life after Boston brace treatment.

DESIGN

Observational retrospective cohort study with analysis of brace treated patients followed from start until at least 10 years after treatment.

SETTING

Patients recruited from the country's entire population consecutively treated at the National Hospital.

POPULATION

365 patients (339 girls/26 boys) with idiopathic scoliosis. Mean (SD) chronological age/bone age at start bracing was 13.2 (1.9)/12.6 (1.9) years. The primary major curve measured 33.2 (7.4°), and the major levels were thoracic (N.=248), thoracolumbar (N.=78) and lumbar (N.=39). Mean bracing time was 2.8 (1.5) years. Long-term follow-up was in average 23.3 (4.1) years after weaning with a mean major curve of 33.0 (13.1°). Successful treatment was defined as a stable primary curve with progression ≤5°, and secondary the SRS-22 questionnaire assessed quality of life.

METHODS

We applied linear or logistic regression with backward elimination. Internal validation was assessed by bootstrapping. Twelve variables were included in the prediction models: age, bone age, scoliosis in close family, major curve size, level, shape, flexibility and in-brace redressement, compliance, curve magnitude after 1 year, treatment time and quality of life (SRS-22).

RESULTS

290 patients (79%) had rated good compliance using the brace >20 hours daily. Treatment failure was observed in 65 patients (18%), and 27 of them were operated. The best baseline predictors were age and brace redressement. During treatment compliance, major curve after 1 year, and treatment time were the best predictors, while thoracic major curve, curve size at start bracing and scoliosis in close family also contributed to the final model. The model's ability to predict quality of life was low.

CONCLUSIONS

The best predictors for a long-term success were good redressement and compliance, unchanged or reduced major curve after one year and short treatment time.

CLINICAL REHABILITATION IMPACT

Predictors at baseline and during early treatment can help identifying patients who benefit from bracing.

Quantitation Analysis of PCDH10 Methylation in Adolescent Idiopathic Scoliosis Using Pyrosequencing Study

STUDY DESIGN

A retrospective and comparative study.

OBJECTIVE

To evaluate the difference of DNA methylation in protocadherin10 (PCDH10) genes between adolescent idiopathic scoliosis (AIS) and normal controls, and to assess the association between DNA methylation and the etiology of AIS.

SUMMARY OF BACKGROUND DATA

The PCDH10 gene showed abnormal expression in AIS. However, the mechanism was still unclear. DNA methylation was an important epigenetic mechanism at the interface between genetics and environmental phenotype, seeming to be a suitable epigenetic mark for the abnormal expression of PCDH10 in AIS.

METHODS

There were 50 AIS patients and 50 healthy controls included in the study. The peripheral blood sample of each participant was taken. The pyrosequencing assay was used to assess the methylation status of PCDH10 promoter and real time PCR (RT-PCR) was used to detect the PCDH10 gene expression. The comparison analysis was performed using independent t test and 2-tailed Pearson coefficients was calculated for the correlation analysis.

RESULTS

The average methylation level was 4.32 ± 0.73 in AIS patients and 3.14 ± 0.97 in healthy controls (P < 0.001). The PCDH10 gene expression was 0.23 ± 0.04 in AIS patients and 0.36 ± 0.08 in normal controls (P < 0.0001). Statistically significant linear correlation was found between PCDH10 gene methylation level and Cobb angle of major curve (P < 0.001). Besides, a significant negative correlation between PCDH10 methylation and PCDH10 gene expression was found (P < 0.001).

CONCLUSION

AIS patients were associated with high DNA methylation level and low gene expression of PCDH10 gene rather than normal controls. The high methylation level indicated high Cobb angle of major curves in AIS. The abnormal DNA methylation may widely exist and serve as a potential mechanism for AIS.

LEVEL OF EVIDENCE

3.

A Novel Coding Variant in SLC39A8 Is Associated With Adolescent Idiopathic Scoliosis in Chinese Han Population

STUDY DESIGN

A genetic case-control association study.

OBJECTIVE

The aim of this study was to investigate the association of SLC39A8 with the susceptibility of adolescent idiopathic scoliosis (AIS) in Chinese Han population.

SUMMARY OF BACKGROUND DATA

A recent exome-wide association study identified a missense variant rs13107325 in SLC39A8 that was associated with AIS. However, there was a lack of study validating the association of this novel mutation with AIS in other populations.

METHODS

The variant rs13107325 was genotyped in 965 AIS patients and 976 healthy controls by allelic specific multiple ligase detection reactions. Variants located in the coding region of SLC39A8 were identified by exon sequencing for 192 AIS patients and 192 controls. Paraspinal muscles from 36 AIS patients and 36 age-matched congenital scoliosis patients were collected for the gene expression analysis. Comparison between the cases and controls was performed with the χ test for genotyping data or with Student t test for gene expression analysis.

RESULTS

For the missense variant rs13107325, there was no case of mutation detected in the patients or the controls. All the subjects had homozygous genotype CC. Exon sequencing revealed that a coding variant rs11097773 of SLC39A8 had a significantly different distribution of minor allele frequency between patients and controls (7.81% vs. 14.8%, P = 0.002). The mRNA expression of SLC39A8 in the patients was remarkably lower than that in the controls (0.0015 ± 0.00026 vs. 0.0021 ± 0.00033, P < 0.001).

CONCLUSION

The association of previously reported novel mutation (rs13107325 in SLC39A8) with AIS was not replicated in the Chinese population. Interestingly, a novel coding variant rs11097773 of SLC39A8 is found significantly associated with AIS. Moreover, the expression of SLC39A8 was obviously decreased in AIS patients. Further study is warranted to clarify the functional role of rs11097773 in the development of AIS.

LEVEL OF EVIDENCE

3.

Utilization of distal radius and ulna classification scheme in predicting growth peak and curve progression in idiopathic scoliosis girls undergoing bracing treatment

PURPOSE

Distal radius and ulna (DRU) classification scheme has been proposed for predicting skeletal maturity in patients with idiopathic scoliosis (IS). However, the utilization of DRU classification scheme in the assessment of growth peak and curve progression in IS was still inconclusive. This study aimed to correlate the distal radius and ulna stages with several indicators for growth potential and to evaluate the predictive value of DRU system for curve progression in braced female IS patients.

METHODS

This was a consecutive longitudinal study including physically immature IS girls receiving standardized bracing treatment and regularly followed up every 3-6 months until brace weaning. The following data of each visit were collected: chronologic age, standing height, Cobb angle, spinal length, Risser sign, digital skeletal age (DSA) scores and DRU scores. The height velocity (HV), spinal growth velocity (SGV) and angle velocity (AV) of each visit were calculated. The correlation among radius stage, ulna stage, Risser sign, height, spinal length, HV, SGV and AV was studied.

RESULTS

Forty braced IS girls with 349 longitudinal whole spine X-rays were reviewed. The average DRU scores at initial visit were R6.5 ± 1.1 and U4.5 ± 1.2 for radius and ulna, respectively. Both the radius stages between R5 and R8 and ulna stages between U3 and U6 indicated high SGV and high HV. The DSA scores were 402.1 ± 48.8 and 430.8 ± 44.4 at R7 and R8, respectively. The AV values were - 5.9 ± 12.4°/y and - 0.4 ± 1.5°/y at R5 and R6, which increased to 5.9 ± 17.3°/y, 3.1 ± 15.7°/y and 4.2 ± 12.2°/y at R7, R8 and R9, respectively. The DSA scores were 387.3 ± 65.7 for U5 and 432.9 ± 48.5 for U6, respectively. The AV values were - 3.1 ± 0.3°/y at U3, - 1.7 ± 9.3°/y at U4, 2.3 ± 16.1°/y at U5, 5.4 ± 15.5°/y at U6 and 4.4 ± 12.9°/y at U7.

CONCLUSIONS

Both distal radius and ulna scores correlate with the longitudinal growth potential, and thus, the DRU scoring scheme is an alternative predictor for growth potential and curve progression in girls with IS. These slides can be retrieved under Electronic Supplementary Material.

A Genetic Predictive Model Estimating the Risk of Developing Adolescent Idiopathic Scoliosis

Background:

Previous GWASs have revealed several susceptible variants associated with adolescent idiopathic scoliosis (AIS). Risk prediction based on these variants can potentially improve disease prognosis. We aimed to evaluate the combined effects of genetic factors on the development of AIS and to further develop a genetic predictive model.

Methods:

A total of 914 AIS patients and 1441 normal controls were included in the discovery stage, which was followed by the replication stage composed of 871 patients and 1239 controls. Genotyping assay was performed to analyze 10 previously reported susceptible variants, including rs678741 of LBX1, rs241215 of AJAP1, rs13398147 of PAX3, rs16934784 of BNC2, rs2050157 of GPR126, rs2180439 of PAX1, rs4940576 of BCL2, rs7593846 of MEIS1, rs7633294 of MAGI1 and rs9810566 of TNIK. Logistic regression analysis was performed to generate a risk predictive model. The predicted risk score was calculated for each participant in the replication stage.

Results:

The association of the 10 variants with AIS was successfully validated. The established model could explain approximately 7.9% of the overall variance. In the replication stage, patients were found to have a remarkably higher risk score as compared to the controls (44.2 ± 14.4 vs. 33.9 ± 12.5, p <0.001). There was a remarkably higher proportion of the risk score i.e. >40 in the patients than in the controls (59% vs. 28.9%, p <0.001).

Conclusion:

Risk predictive model based on the previously reported genetic variants has a remarkable discriminative power. More clinical and genetic factors need to be studied, to further improve the proba-bility to predict the onset of AIS.

Bracing In The Treatment Of Adolescent Idiopathic Scoliosis: Evidence To Date

Brace effectiveness for adolescent idiopathic scoliosis was controversial until recent studies provided high quality of evidence that bracing can decrease likelihood of progression and need for operative treatment. Very low evidence exists regarding bracing over 40^ο and adult degenerative scoliosis. Initial in-brace correction and compliance seem to be the most important predictive factors for successful treatment outcome. However, the amount of correction and adherence to wearing hours have not been established yet. Moderate evidence suggests that thoracic and double curves, and curves over 30^ο at an early growth stage have more risk for failure. High and low body mass index scores are also associated with low successful rates. CAD/CAM braces have shown better initial correction and are more comfortable than conventional plaster cast braces. For a curve at high risk of progression, rigid and day-time braces are significantly more effective than soft or night-time braces. No safe conclusion on effectiveness can be drawn while comparing symmetrical and asymmetrical brace designs. The addition of physiotherapeutic scoliosis-specific exercises in brace treatment can provide better outcomes and is recommended, when possible. Despite the growing evidence for brace effectiveness, there is still an imperative need for future high methodological quality studies to be conducted.

Rare variant of HSPG2 is not involved in the development of adolescent idiopathic scoliosis: evidence from a large-scale replication study

BACKGROUND

Rare variants of HSPG2 have recently been reported to function as a potential contributor to the susceptibility of adolescent idiopathic scoliosis (AIS) in the Caucasians. A replication study in the different population is warranted to validate the role of HSPG2 in AIS. The aim of this study was to determine the association between HSPG2 and AIS in the Chinese patients and to further investigate its influence on the phenotype of the patients.

METHODS

SNVs p.Asn786Ser of HSPG2 was genotyped in 1752 patients and 1584 normal controls using multiple ligase detection reactions. The mRNA expression of HSPG2 in the paraspinal muscles was quantified for 90 patients and 26 controls. The The Student's t test was used to analyze the inter-group comparison of the HSPG2 expression. The relationship between the HSPG2 expression and the curve magnitude of the patients was analyzed by the Pearson correlation analysis.

RESULTS

No case of mutation in the reported SNV p.Asn786Ser of HSPG2 was found in our cohort. The mRNA expression of HSPG2 in patients was comparable with that in the controls (0.0016 ± 0.0013 vs. 0.0019 ± 0.0012, p = 0.29). 42 patients with curve magnitude > 60 degrees were assigned to the severe curve group. The other 58 patients were assigned to the moderate curve group. These two groups were found to have comparable HSPG2 expression (0.0015 ± 0.0011 vs. 0.0017 ± 0.0014, p = 0.57). And there was no remarkable correlation between the expression level of HSPG2 and the curve severity (r = 0.131, p = 0.71).

CONCLUSIONS

HSPG2 gene was not associated with the susceptibility or the phenotypes of AIS in the Chinese population. The whole HSPG2 gene can be sequenced in more AIS patients to identify potentially causative mutations.

Abnormal PITX1 gene methylation in adolescent idiopathic scoliosis: a pilot study

Background

The gene of pituitary homeobox 1 (PITX1) has been reported to be down-regulated in adolescent idiopathic scoliosis (AIS), of which the cause has not been well addressed. The abnormal DNA methylation was recently assumed to be an important mechanism for the down-regulated genes expression. However, the association between PITX1 promoter methylation and the etiology of AIS was not clear.

Methods

The peripheral blood samples of 50 AIS patients and 50 healthy controls were collected and the genomic DNA was extracted. The pyrosequencing assay was used to assess the methylation status of PITX1 promoter and real-time quantitative polymerase chain reaction (PCR) was used to detect the PITX1 gene expression. Comparison analysis was performed using independent t test and Chi-square tests, while correlation analysis were performed with 2-tailed Pearson coefficients.

Results

The mean methylation level was (3.52 ± 0.96)% in AIS and (1.40 ± 0.81)% in healthy controls (P < 0.0001). The PITX1 gene expression was 0.15 ± 0.08 in AIS and 0.80 ± 0.55 in healthy controls (P < 0.0001). The comparative analysis showed significant difference in age (P = 0.021) and Cobb angle of the main curve (P = 0.0001) between AIS groups with positive and negative methylation. The methylation level of 6 CpG sites in PITX1 promoters was significantly associated with Cobb angle of the main curve (P < 0.001) in AIS. No statistical relationship between PITX1 promoter methylation and gene expression was found in AIS (P = 0.842).

Conclusion

Significantly higher methylation level and lower PITX1 gene expression are found in AIS patients. PITX1 methylation is associated with Cobb angles of the main curves in AIS. DNA methylation thus plays an important role in the etiology and curve progression in AIS.

Association between braced curve behavior by pubertal growth peak and bracing effectiveness in female idiopathic scoliosis: a longitudinal cohort study

BACKGROUND

Pre-pubertal idiopathic scoliosis (IS) is associated with high risk of bracing ineffectiveness. Integrated multidimensional maturity assessments are useful but complex to predict the high-risk occurrence of curve progression. This study is designed to provide a simple screening method for brace effectiveness by determining whether or not the braced curve behavior at growth spurt, being defined as variations in Cobb angle velocity (AV) at peak height velocity (PHV), can be a new factor predictive of brace outcome prescribed before PHV.

METHODS

This is a retrospective study of a series of 35 IS girls with simplified skeletal maturity score no more than 3 at initiation of bracing treatment and followed up through the growth spurt until brace weaning or surgery. Serial Cobb angle and maturity indicators involving height velocity, Risser sign, triradiate cartilage, simplified skeletal maturity score and distal radius and ulna classification were assessed and patients were stratified into either a positive or negative category based on a positive or negative value of AV at PHV. Comparisons were made between the positive and negative AV groups, as well as the failed and successful bracing groups, using independent sample T test and crosstab analysis. Logistic regression analysis was used to identify the predictive factors of failed brace treatment.

RESULTS

Brace treatment prescribed before PHV was found to have an overall failure rate of 57.1% and a surgical rate of 45.7%. Negative AV at PHV accounting for 54.3% of the recruited patients were associated with lower brace failure rate (36.8% vs. 81.2%, p = 0.016) and surgical rate (21.1% vs. 75.0%, p = 0.002). Patients in the failed bracing group showed higher ratio of thoracic curve (80.0% vs. 26.7%,p = 0.002) and higher AV at growth peak (2.3 ± 9.1 vs. -6.5 ± 11.4°/yrs., p = 0.016). The logistic regression analysis revealed that positive AV at PHV (OR = 9.268, 95% CI = 1.279-67.137, p = 0.028) and thoracic curve type (OR = 13.391, 95% CI = 2.006-89.412, p = 0.007) were strong predictive factors of ineffective brace treatment initiated before PHV.

CONCLUSIONS

Sustained curve correction following bracing despite early onset and rapid pubertal growth was strongly predictive of effective brace control of scoliosis.

Association between single nucleotide polymorphisms of TPH1 and TPH2 genes, and depressive disorders

Tryptophan catabolites pathway disorders are observed in patients with depression. Moreover, single nucleotide polymorphisms of tryptophan hydroxylase genes may modulate the risk of depression occurrence. The objective of our study was to confirm the association between the presence of polymorphic variants of TPH1 and TPH2 genes, and the development of depressive disorders. Six polymorphisms were selected: c.804-7C>A (rs10488682), c.-1668T>A (rs623580), c.803+221C>A (rs1800532), c.-173A>T (rs1799913)-TPH1, c.-1449C>A (rs7963803), and c.-844G>T (rs4570625)-TPH2. A total of 510 DNA samples (230 controls and 280 patients) were genotyped using TaqMan probes. Among the studied polymoorphisms, the G/G genotype and G allele of c.804-7C>A-TPH1, the T/T homozygote of c.803+221C>A-TPH1, the A/A genotype and A allele of c.1668T>A-TPH1, the G/G homozygote and G allele of c.-844G>T-TPH2, and the C/A heterozygote and A allele of c.-1449C>A-TPH2 were associated with the occurrence of depression. However, the T/T homozygote of c.-1668T>A-TPH1, the G/T heterozygote and T allele of c.-844G>T-TPH2, and the C/C homozygote and C allele of c.-1449C>A-TPH2 decreased the risk of development of depressive disorders. Each of the studied polymorphisms modulated the risk of depression for selected genotypes and alleles. These results support the hypothesis regarding the involvement of the pathway in the pathogenesis of depression.

Association Between the Estrogen Receptor Beta (ESR2) Rs1256120 Single Nucleotide Polymorphism and Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The aim of this study was to assess and synthesize the current evidence on the association between the rs1256120 single nucleotide polymorphism (SNP) of the estrogen receptor beta gene (ESR2) and adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Hormonal disturbance has been postulated as a potential etiological factor in the development of AIS. As estrogen receptors are important mediators of estrogen response, mutations in these genes, including rs1256120 of ESR2, have been chosen as susceptibility candidates for AIS predisposition. The association of rs1256120 with AIS has been investigated in several recent studies, but showed conflicting evidence. We conducted a systematic review to evaluate the strength of this body of evidence and quantitative synthesis to examine sources of heterogeneity.

METHODS

This study conformed to PRISMA guidelines. Using a sensitive search strategy, PubMed (MEDLINE), EMBASE, and HuGE Literature Finder databases were searched to identify relevant studies for inclusion in the systematic review and meta-analysis. Risk of bias was assessed using a modified Newcastle-Ottawa Scale. The inverse variance model was used to calculate summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the allelic (C vs. T) and genotypic comparisons. Planned subgroup and sensitivity analyses were performed.

RESULTS

Three studies were included for systematic review and meta-analysis (n = 1264 AIS cases and n=1020 controls). A null relationship was found between rs1256120 and AIS (allelic OR = 1.20, 95% CI: 0.81-1.78, P = 0.36, I = 84.9%), with the first reported association likely to be false-positive and contributing substantially to heterogeneity.

CONCLUSION

Findings from the systematic review and meta-analysis suggest that rs1256120 of ESR2 is unlikely to be a predisposing or disease-modifying genetic risk factor for AIS.

LEVEL OF EVIDENCE

2.

Integrated Multidimensional Maturity Assessments Predicting the High-risk Occurrence of Peak Angle Velocity During Puberty in Progressive Female Idiopathic Scoliosis

STUDY DESIGN

A consecutive and prospective longitudinal study.

OBJECTIVE

To propose an integrated multidimensional maturity assessment that was designated as forming a reliable system precisely predicting the high-risk occurrence of peak angle velocity (PAV) in a group of progressive braced female idiopathic scoliosis (IS).

SUMMARY OF BACKGROUND DATA

Scoliosis deterioration is believed to keep pace with the evolution of skeletal maturity during puberty. There is, however, a paucity of data in the literature regarding which unidimensional or multidimensional maturity assessment was most informational, and could be employed to predict the likelihood of significant curve progression.

MATERIALS AND METHODS

In this prospective study, braced IS girls with open triradiate cartilage were recruited and followed up at 6-month regular intervals. At each visit, the following data were collected: chronologic age, stage of menses, standing height, Cobb angle of the main curve, spine length, status of triradiate cartilage, Risser sign, and digital skeletal age (DSA) scores. The height velocity (HV) and spine length velocity (SLV), as well as the angle velocity (AV) of each visit were calculated. Finally, those with main curve progression of ≥5 degrees during brace treatment and with a minimum of 2-year follow-up covering the closure of the triradiate cartilage were recruited in this analysis, and their PAV was defined as the peak of AV curves during the whole follow-up period in puberty. Logistic regression analysis was used to evaluate the contribution of each measurement to the risk of PAV onset.

RESULTS

Thirty-six IS girls were finally recruited in the study, with an average age of 10.8 years at initial visit and 11.8 years at PAV. The average DSA score, spine length, standing height, and Cobb angle of main curve at PAV were 479.5, 326.7 mm, 150.8 cm, and 26.5 degrees, respectively. The average HV, AV, and SLV at PAV were 8.3 cm, 7.8 degrees, and 28.2 mm/y, respectively. The PAV occurred with Risser 0, 1, and 2 in 80.6%, 11.1%, and 8.3% of the IS girls and closed triradiate cartilages were found at PAV in all the girls. The logistic regression model revealed that the following variables contributed significantly to high-risk occurrence of PAV: chronologic age between 11 and 13 years [odds ratio (OR)=3.961; 95% confidence interval (CI), 1.023-15.342], Risser 0 (OR=14.261; 95% CI, 1.167-65.528), closed triradiate cartilage (OR=6.590; 95% CI, 1.612-26.943), DSA scores between 400 and 500 (OR=6.042; 95% CI, 1.282-28.482), HV>6 cm/y (OR=5.711; 95% CI, 1.105-29.526), Cobb angle of main curve >30 degrees (OR=5.492; 95% CI, 1.151-26.207) and SLV>20 mm/y (OR=5.973; 95% CI, 1.546-23.071).

CONCLUSIONS

Integrated multidimensional maturity assessments, defined as chronologic age between 11 and 13 years, modified Risser 0, DSA scores between 400 and 500, HV>6 cm/y, and SLV>20 mm/y, combined with preexisting scoliotic curve >30 degrees, were prone to increase the risk of entering the rapid curve acceleration phase in progressive IS girls.

Initial Correction Rate Can be Predictive of the Outcome of Brace Treatment in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

To determine the definite cut-off value of initial correction rate (ICR) that could be predictive of bracing outcome in patients with adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Earlier studies showed that braced patients with a better ICR could finally have a higher probability of successful outcome. However, it remains controversial what definitive cut-off value of ICR is required to accurately predict the outcome.

MATERIALS AND METHODS

A cohort of 488 adolescent idiopathic scoliosis patients who have completed the brace treatment with a minimum of 2-year follow-up were included in the current study. Curve progression of ≤5 degrees was used to define the success of brace treatment. The success group and the failure group were compared in terms of initial Risser sign, initial age, sex, curve pattern, initial curve magnitude, and ICR. The receiver operating characteristics curve was used to define the definite cut-off point of initial curve correction rate. A logistic regression model was created to determine the independent predictors of the bracing outcome.

RESULTS

At the beginning of brace treatment, the mean age of the cohort was 13.2±1.5 years, and the mean curve magnitude was 29.5 ± 6.6 degrees. At the final follow-up, 368 patients were successfully treated by bracing. Compared with the success group, the failure group was found to have significantly younger age, lower Risser sign, and lower ICR. According to the receiver operating characteristic curve, the best cut-off value of ICR was 10%. The logistic regression model showed that ICR was significantly associated with the outcome of brace treatment with an odds ratio of 9.61.

CONCLUSIONS

Patients with low ICR, low Risser sign, and young age could have a remarkably high risk of bracing failure. A rate of 10% was the optimal cut-off point for ICR, which can be used to effectively stratify braced patients.

Is Brace Treatment Appropriate for Adolescent Idiopathic Scoliosis Patients Refusing Surgery With Cobb Angle Between 40 and 50 Degrees

STUDY DESIGN

A retrospective study to determine whether brace treatment is appropriate for adolescent idiopathic scoliosis patients with Cobb angle between 40 and 50 degrees who utterly refuse surgery.

OBJECTIVE

To investigate whether it is possible to halt the curve progression of adolescent idiopathic scoliosis patients with Cobb angle between 40 and 50 degrees through bracing, and to identify factors that could influence the effectiveness of brace treatment in such patients.

SUMMARY OF BACKGROUND DATA

Despite of the great achievements in treating patients with mild curve, bracing has been considered to be inappropriate for those with curves of >40 degrees. However, in clinical practice surgeons could encounter a series of patients who utterly refused surgery and insisted on wearing brace despite having a curve >40 degrees.

METHODS

A cohort of 54 patients with Cobb angle between 40 and 50 degrees were reviewed in the current study. All the patients refused surgery at their first visit and insisted on receiving brace treatment. Each patient was followed up at an interval of 3-6 months. Variants such as initial Risser sign, initial age, sex, curve pattern, and initial curve magnitude were compared between patients with and without curve progression. A logistic regression analysis was performed to determine the independent predictors of the curve progression.

RESULTS

On the whole, the curve progressed in 35 patients, remained stable in 12 patients, and improved in the else 7 patients. All the patients with curve progression finally received surgical intervention. The mean grade of initial Risser sign in patients with curve progression was significantly lower than that in patients with stable or improved curve (0.3±0.8 vs. 1.2±1.4, P=0.02). In terms of sex, age, curve pattern, and curve magnitude, there were no significant differences between the 2 categories. The results of the logistic regression analysis showed that initial Risser sign of grade 0 or 1 had significant associations with the curve progression of patients with curves >40 degrees (odds ratio, 7.51, 95% confidence intervak, 1.27-24.43, P=0.02).

CONCLUSIONS

The effectiveness of brace treatment significantly decreases when applied to patients with curve magnitude between 40 and 50 degrees. Although a majority of these patients will inevitably undergo a surgical intervention, and thus wearing a brace may not be the best alternative to surgical intervention; there are patients who will stabilize with the brace until skeletal maturity thus warranting this option for those patients refusing surgical intervention with curves between 40 and 50 degrees.

Low body mass index can be predictive of bracing failure in patients with adolescent idiopathic scoliosis: a retrospective study

PURPOSES

To determine the relationship between low body mass index (BMI) and the outcome of brace treatment in patients with adolescent idiopathic scoliosis (AIS).

METHODS

350 braced female AIS patients were included in this study. The baseline characteristics of the patient were recorded at their first visit, including age, Risser sign, digital skeletal age, BMI, curve pattern, and curve magnitude. Underweight was defined as lower than the 5th percentile of the sex- and age-specific BMI. The treatment was considered as a failure if the curve progressed more than 5°, or if patients underwent surgery. According to the final outcome of brace treatment, the cohort was divided into the success group and the failure group. A logistic regression model was created to determine the independent predictors of the bracing outcome.

RESULTS

24.5% (86/350) of the patients were identified as underweight at their initial visit, which was significantly higher than the rate of 13.1% (46/350) at the final follow-up (p < 0.001). At the initial visit of the patients, the rate of underweight was 17.6% (45/255) in the success group, which was significantly lower than the rate of 43.1% (41/95) in the failure group (p < 0.001). Logistic regression analysis showed that low BMI was significantly associated with bracing failure (p < 0.001).

CONCLUSION

The low BMI could be predictive of bracing failure in AIS patients, which should be taken into account when surgeons prescribe brace treatment to such patients.

Spinal growth velocity versus height velocity in predicting curve progression in peri-pubertal girls with idiopathic scoliosis

Background

Height velocity (HV) is traditionally used to monitor the residual growth potential in idiopathic scoliosis (IS). The temporal timing of rapid increase in standing height often does not match exactly that of the increase in spine height. The purposes of this study were to analyze the correlation between change of angle velocity (AV) vs the changes of spinal growth velocity (SGV) and HV, and the associated predictive value on curve progression in IS.

Methods

Pre-pubertal IS girls with single curve receiving standardized bracing treatment followed longitudinally with documented curve progression >5° were retrospectively reviewed. The age, standing height, Cobb angle (main curve), spinal length, Risser sign, HV, SGV and AV at each visit were measured and calculated. The visit with the highest AV value of each patient was selected for the final analysis and correlated with the corresponding peak height velocity (PHV) and peak spinal growth velocity (PSGV).

Results

Sixty-two IS girls were reviewed. Chi-square test revealed PSGV contributed more to the highest AV than PHV (P = 0.001). Pearson correlation analysis demonstrated that AV was correlated with SGV (r = 0.454, P < 0.001) and HV (r = 0.280, P = 0.027). Multiple linear regression analysis showed that high AV was better predicted by higher SGV (B = 0.321, P = 0.007) rather than higher HV (B = 0.259, P = 0.362) (R = 0.467).

Conclusions

Variations of spinal growth velocity exerted more direct influence over changes in angle velocity as compared with height velocity. High spinal growth velocity predisposed to more rapid curve progression in patients with idiopathic scoliosis.

Association Study between Promoter Polymorphism of TPH1 and Progression of Idiopathic Scoliosis

The concept of disease-modifier genes as an element of genetic heterogeneity has been widely accepted and reported. The aim of the current study is to investigate the association between the promoter polymorphism TPH1 (rs10488682) and progression of idiopathic scoliosis (IS) in Eastern European population sample. A total of 105 patients and 210 healthy gender-matched controls were enrolled in this study. The TPH1 promoter polymorphism was genotyped by amplification followed by restriction. The statistical analysis was performed by Fisher's Exact Test. The results indicated that the genotypes and alleles of TPH1 (rs10488682) are not correlated with curve severity, curve pattern, or bracing. Therefore, the examined polymorphic variant could not be considered as a genetic factor with modifying effect of IS. In conclusion, this case-control study revealed no statistically significant association between TPH1 (rs10488682) and progression of IS in Eastern European population sample. These preliminary results should be replicated in extended population studies including larger sample sizes. The identification of molecular markers for IS could be useful for a more accurate prognosis of the risk for a rapid progression of the curve. That would permit early stage treatment of the patient with the least invasive procedures.

Association of Calcium and Phosphate Balance, Vitamin D, PTH, and Calcitonin in Patients With Adolescent Idiopathic Scoliosis

STUDY DESIGN

A cross-sectional study of 2 groups of patients with scoliosis, and an age-matched control group was conducted. Each of the groups such as patients with adolescent idiopathic scoliosis (AIS) as well as control group were divided additionally into 2 groups: premenarcheal and postmenarcheal girls.

OBJECTIVE

The aim of the study was to determine the levels of 25-OH-vitamin D3, calcium and phosphate, parathyroid hormone (PTH), and calcitonin in serum of pre- and postmenarcheal girls with AIS and corresponding groups of scoliosis-free controls.

SUMMARY OF BACKGROUND DATA

The primary etiology and pathogenesis of AIS remains unknown. It is assumed that vitamin D deficiency and genetic predisposition, for example, polymorphisms of vitamin D receptor, have a great significance. Vitamin D plays a key role in skeletal development and prevents bone atrophy, affects the absorption of calcium, maintains calcium-phosphate homeostasis, and the bone matrix mineralization. Its deficiency can result in a wide variety of skeletal deformities, low bone mass, and then leads to the disappearance of bone. Defects in trabecular bone structure and/or bone mineralization are the main features of scoliosis. Some studies have reported that Vitamin D deficiency is common among patients with AIS. The mechanism of Vitamin D action on scoliosis development is still unclear.

METHODS

Determination of serum 25-OH-D3 levels was performed using high-performance liquid chromatography chromatography; concentrations of calcium and phosphate were measured using colorimetric methods, and concentration of PTH and calcitonin was measured using ELISA system.

RESULTS

Reduction in the serum levels of 25-OH-D3 and calcitonin in girls with AIS compared with healthy girls was demonstrated.

CONCLUSION

The phosphate-calcium balance and PTH level seem to be normal in patients with AIS. The calcitonin level in girls with AIS is 2-fold lower than in healthy subjects. It is possible that the deficiency of vitamin D can be involved in AIS.

LEVEL OF EVIDENCE

4.

Predictors of spine deformity progression in adolescent idiopathic scoliosis: A systematic review with meta-analysis

AIM: To evaluate published data on the predictors of progressive adolescent idiopathic scoliosis (AIS) in order to evaluate their efficacy and level of evidence.

METHODS: Selection criteria: (1) study design: randomized controlled clinical trials, prospective cohort studies and case series, retrospective comparative and none comparative studies; (2) participants: adolescents with AIS aged from 10 to 20 years; and (3) treatment: observation, bracing, and other. Search method: Ovid MEDLINE, Embase, the Cochrane Library, PubMed and patent data bases. All years through August 2014 were included. Data were collected that showed an association between the studied characteristics and the progression of AIS or the severity of the spine deformity. Odds ratio (OR), sensitivity, specificity, positive and negative predictive values were also collected. A meta-analysis was performed to evaluate the pooled OR and predictive values, if more than 1 study presented a result. The GRADE approach was applied to evaluate the level of evidence.

RESULTS: The review included 25 studies. All studies showed statistically significant or borderline association between severity or progression of AIS with the following characteristics: (1) An increase of the Cobb angle or axial rotation during brace treatment; (2) decrease of the rib-vertebral angle at the apical level of the convex side during brace treatment; (3) initial Cobb angle severity (> 25^o); (4) osteopenia; (5) patient age < 13 years at diagnosis; (6) premenarche status; (7) skeletal immaturity; (8) thoracic deformity; (9) brain stem vestibular dysfunction; and (10) multiple indices combining radiographic, demographic, and physiologic characteristics. Single nucleotide polymorphisms of the following genes: (1) calmodulin 1; (2) estrogen receptor 1; (3) tryptophan hydroxylase 1; (3) insulin-like growth factor 1; (5) neurotrophin 3; (6) interleukin-17 receptor C; (7) melatonin receptor 1B, and (8) ScoliScore test. Other predictors included: (1) impairment of melatonin signaling in osteoblasts and peripheral blood mononuclear cells (PBMC); (2) G-protein signaling dysfunction in PBMC; and (3) the level of platelet calmodulin. However, predictive values of all these findings were limited, and the levels of evidence were low. The pooled result of brace treatment outcomes demonstrated that around 27% of patents with AIS experienced exacerbation of the spine deformity during or after brace treatment, and 15% required surgical correction. However, the level of evidence is also low due to the limitations of the included studies.

CONCLUSION: This review did not reveal any methods for the prediction of progression in AIS that could be recommended for clinical use as diagnostic criteria.

Initial Cobb angle reduction velocity following bracing as a new predictor for curve progression in adolescent idiopathic scoliosis

PURPOSE

The initial correction rate (ICR) has been widely used as a predictor for curve progression in adolescent idiopathic scoliosis (AIS) undergoing bracing treatment. We proposed a new parameter, the initial Cobb angle reduction velocity (ARV), for prediction of curve progression. The purpose of this study was to identify whether the initial ARV was a more effective predictor than ICR for curve progression in AIS patients undergoing brace treatment, and to evaluate the ideal cut-off point of initial ARV for prediction of curve progression.

METHODS

This was a retrospective cohort study on AIS girls receiving standardized bracing treatment regularly followed up every 3-6 months. Standardized SRS criteria for bracing study were utilized in the case selection. The demographic data, maturity status and Cobb angle of each visit were recorded. The initial ARV and ICR were identified. Patients were divided into progressive (≥6°) and non-progressive (<6°) groups based on their final bracing outcome. Differences between two groups were identified and logistic regression analysis was applied to compare the predictive values of initial ARV and ICR for curve progression during bracing treatment.

RESULTS

Seventy-six patients were included in the non-progressive group and 19 in the progressive group. Significant differences between non-progressive and progressive groups were found in terms of initial ARV (12.8 ± 21.4°/year vs -5.4 ± 15.2°/year, P = 0.001) and ICR (12.1 ± 20.7 % vs -5.8 ± 18.0 %, P = 0.001). The logistic regression analysis revealed that age at initial visit (OR 1.742, P = 0.043) and initial ARV (OR 1.057, P = 0.002) had higher predictive values than ICR (P = 0.601) for curve progression in braced AIS girls. The ideal cut-off point of initial ARV was 10°/year (OR 8.959, P = 0.005) for the prediction of curve progression.

CONCLUSIONS

The initial Cobb angle reduction velocity serves as a better predictor for curve progression than initial correction rate in braced AIS patients with follow-up interval of 3-6 months. At the second visit following bracing prescription, those AIS patients with reduction velocity in Cobb angle lower than 10°/year have significantly higher risk of curve progression.

Estrogen receptor 2 gene polymorphism in idiopathic scoliosis

STUDY DESIGN

A genetic association study of estrogen receptor 2 gene (ESR2) polymorphisms in idiopathic scoliosis (IS).

OBJECTIVE

To investigate association of the ESR2 polymorphisms with either predisposition to or progression of IS in Central European population.

SUMMARY OF BACKGROUND DATA

In ESR2 the rs1256120 polymorphism was described to be associated with predisposition to and severity of IS in Chinese population. This observation has not been confirmed in Japanese population. The ESR2 rs4986938 and rs1256049 polymorphisms were described to present association with breast cancer, rheumatoid arthritis, and bone mineral density, however the association with IS has not been evaluated.

METHODS

Case-control study of 248 females with IS and 243 healthy females was performed. Three single-nucleotide polymorphisms were studied using polymerase chain reaction-restriction fragments length polymorphism technique with the restriction enzymes: AlwNI (C/T rs1256120), AluI (A/G rs4986938), and RsaI (A/G rs1256049). The patients' medical history was evaluated, Cobb angle was measured and surgery rate established. The patients were analyzed in 3 subgroups according to curve progression velocity.

RESULTS

Neither the genotypes nor alleles distribution showed significant differences between patients with IS and healthy controls. There was no significant difference in genotype or allele frequency. In the AluI site polymorphism a significant difference in mean Cobb angle between genotypes was found: (AA, 31.9° ± 14.2°; AG, 43.2° ± 17.8°; and GG, 38.9° ± 19.0°), P = 0.002. There was significant difference in genotype distribution between patients with moderate (<40°) versus severe (≥40°) scoliosis, P = 0.0011; the minor allele frequency (AA) in recessive model of penetration was over-represented in patients with Cobb angle below 40°, P = 0.0075, odds ratio = 3.65.

CONCLUSION

No association between ESR2 polymorphism and predisposition to IS was found in Caucasian females. None of the previously reported associations of AlwNI site polymorphism could be confirmed. ESR2 AluI site polymorphism may be associated with curve severity.

LEVEL OF EVIDENCE

N/A.

Ultrastructure of Intervertebral Disc and Vertebra-Disc Junctions Zones as a Link in Etiopathogenesis of Idiopathic Scoliosis

Background Context. There is no general accepted theory on the etiology of idiopathic scoliosis (IS). An important role of the vertebrae endplate physes (VEPh) and intervertebral discs (IVD) in spinal curve progression is acknowledged, but ultrastructural mechanisms are not well understood. Purpose. To analyze the current literature on ultrastructural characteristics of VEPh and IVD in the context of IS etiology. Study Design/Setting. A literature review. Results. There is strong evidence for multifactorial etiology of IS. Early wedging of vertebra bodies is likely due to laterally directed appositional bone growth at the concave side, caused by a combination of increased cell proliferation at the vertebrae endplate and altered mechanical properties of the outer annulus fibrosus of the adjacent IVD. Genetic defects in bending proteins necessary for IVD lamellar organization underlie altered mechanical properties. Asymmetrical ligaments, muscular stretch, and spine instability may also play roles in curve formation. Conclusions. Development of a reliable, cost effective method for identifying patients at high risk for curve progression is needed and could lead to a paradigm shift in treatment options. Unnecessary anxiety, bracing, and radiation could potentially be minimized and high risk patient could receive surgery earlier, rendering better outcomes with fewer fused segments needed to mitigate curve progression.

Matrilin-2 is a widely distributed extracellular matrix protein and a potential biomarker in the early stage of osteoarthritis in articular cartilage

In this study, we first generated and characterized a polyclonal antibody against unique domain of matrlin-2 and then used this specific antibody to assess the expression pattern of matrilin-2 by immunohistochemistry. We found that marilin-2 is widely distributed in the connective tissues of many mouse tissues including heart, colon, penis, esophagus, lung, kidney, tracheal cartilage, developmental bone, and adult bone. The expression level of matrilin-2 was remarkably increased in the tissues of osteoarthritis developmental articular cartilage, compared to normal healthy tissues. Furthermore, we determined matrilin-2 expression in specific epithelial cells in stomach and ductal epithelial cells of salivary gland. In other tissues, the positive signals were mainly located around cardiac muscle cells and Purkinje fibers in the heart; corpus spongiosum in the penis; submucosa in the colon and esophagus; extracellular matrix of cartilage in the tracheal cartilage; and, glomerulus, the basement membrane of distal convoluted tubule and renal matrix in kidney. These observations indicated that the distribution pattern of matrilin-2 is heterogeneous in each tissue. Matrilin-2 may play an important role in the communication of matrix to matrix and matrix to cells and will be used as a potential biomarker in the early stage of osteoarthritis of articular cartilage.

The current status of bracing for patients with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis affects about 3% of children. Non-operative measures are aimed at altering the natural history to maintain the size of the curve below 40° at skeletal maturity. The application of braces to treat spinal deformity pre-dates the era of evidence-based medicine, and there is a paucity of irrefutable prospective evidence in the literature to support their use and their effectiveness has been questioned. This review considers this evidence. The weight of the evidence is in favour of bracing over observation. The most recent literature has moved away from addressing this question, and instead focuses on developments in the design of braces and ways to improve compliance.

XbaI and PvuII polymorphisms of estrogen receptor 1 gene in females with idiopathic scoliosis: no association with occurrence or clinical form

INTRODUCTION

XbaI single nucleotide polymorphism (SNP) (A/G rs934099) in estrogen receptor 1 gene (ESR1) was described to be associated with curve severity in Japanese idiopathic scoliosis (IS) patients and in Chinese patients with both curve severity and predisposition to IS. PvuII SNP (C/T rs2234693) of ESR1 was described to be associated with the occurrence of IS in the Chinese population; however, two replication studies did not confirm the findings. The ESR1 SNPs have never been studied in Caucasian IS patients.

METHODS

Case-control study. 287 females with IS underwent clinical, radiological and genetic examinations. The patients were divided into three groups according to curve progression velocity: non-progressive IS, slowly progressive IS (progression <1° per month), and rapidly progressive IS (progression ≥1° per month). The radiological maximum Cobb angle was measured and surgery rate established. A control group consisted of 182 healthy females.

RESULTS

All results followed Hardy-Weinberg equilibrium. In the case-control study, genotype frequency in the patients did not differ for the XbaI (AA = 33.5%, AG = 49.1%, GG = 17.4%), nor for the PvuII (TT = 26.8%, TC = 50.2%, CC = 23.0%) comparing to controls (AA = 33.5%, AG = 50.5%, GG = 15.9%) and (TT = 23.1%, TC = 51.1%, CC = 25.8%), respectively, p = 0.3685, p = 0.6046. The haplotype frequency for the patients (AT = 47.1%, GC = 39.2%, AC = 8.9%, GT = 2.8%) did not differ from the controls (AT = 44.8%, GC = 37.4%, AC = 14.0%, GT = 3.8%), p = 0.0645. No difference was found either in XbaI (p = 0.8671) or PvuII (p = 0.3601) allele distribution between the patients and the controls. In the case study, there was no significant difference in genotype frequency for the non-progressive, slowly progressive, and rapidly progressive scoliosis. No difference was found in genotype or haplotype distribution for the mean maximum Cobb angle or the surgery rate.

CONCLUSIONS

No association was found between ESR1 XbaI or ESR1 PvuII SNP and idiopathic scoliosis in Caucasian females. None of the previously reported associations could be confirmed, regarding curve severity, progression or operation rate.

Good brace compliance reduced curve progression and surgical rates in patients with idiopathic scoliosis

PURPOSE

To examine the association between brace compliance and outcome.

PATIENTS AND METHODS

495 (457 females) patients with late onset juvenile and adolescent idiopathic scoliosis were examined prospectively before bracing and at least 2 years after brace weaning. One spine surgeon examined all patients. 381 (353 females) answered a standardised questionnaire and 355 had radiological examination after median 24 years. Compliance was defined as brace wear >20 h daily until weaning. Main outcomes were curve progression and surgery.

RESULTS

At weaning, 76/389 compliers and 59/106 non-compliers had curve progression ≥6° (OR 5.2, 95 % CI 3.3-8.2). At long-term the numbers were 68/284 and 46/71 (OR 5.8, 95 % CI 3.3-10.2), 10/284 versus 17/71 had been operated (OR 8.6, 95 % CI 3.7-19.9).

CONCLUSION

We conclude that the risk for curve progression and surgery are reduced in patients with good brace compliance.

Does brace treatment impact upon the flexibility and the correctability of idiopathic scoliosis in adolescents?

PURPOSE

Brace treatment has served as a vital non-surgical procedure for immature adolescent idiopathic scoliosis (AIS) patients with a mild or moderate curve. For the patients who fail in bracing and resort to surgery, it is unclear whether prior full-time brace treatment significantly influences outcomes. This study aims to investigate whether prior brace treatment has a negative impact upon the flexibility and correctability of the main curve in patients with AIS.

METHODS

The participants were collected from female AIS patients who underwent posterior correction surgery with pedicle screw instrumentation from August 2006 to December 2010, with or without prior brace treatment. Patients included in Group A had prior brace treatment over a 1-year period, and underwent surgery within 6 months after cessation of bracing; those in Group B received no prior treatment and were randomly selected from our database. Curve flexibility pre-surgery and curve correctability post-surgery were computed and compared between both groups and subgroups according to the curve location.

RESULTS

Each group consisted of 35 patients. Age, curve magnitude and location were comparable between the two groups. Before surgery, patients in Group A had a slightly lower curve flexibility than those in Group B (52 vs. 60 %, P = 0.036). After surgery, satisfactory correction results were observed in both groups, but the average post-operative main curve magnitude of patients in Group B was 4° less than that of Group A (10° vs. 14°, P = 0.010). The curve correctability in Group B was significantly higher than that in Group A (80 vs. 74 %, P = 0.002). No matter what curve pattern the patient had, having a prior history of brace treatment resulted in a trend of lower flexibility and correctability of their scoliosis.

CONCLUSIONS

Good surgical correction can be achieved in AIS patients who have been unsuccessful with prior brace treatment. However, a history of prior brace treatment leads to a trend of lowering the curve flexibility, and in turn, negatively impacts upon the curve correctability.

Research in orthopaedics from China has thrived over the last decade: a bibliometric analysis of publication activity

INTRODUCTION

Over the past decades, there have been great advances in orthopaedics in China. The purpose of this study was to investigate the orthopaedic research output in the three Chinese-speaking regions - the Mainland (ML), Hong Kong (HK), and Taiwan (TW).

HYPOTHESIS

We hypothesized that there was a positive trend in China orthopaedic research during the past decade and this regardless of the Chinese-speaking regions of origin.

MATERIALS AND METHODS

Forty-nine orthopaedic journals were retrieved from the PubMed database and Science Citation Index Expanded. Articles from ML, TW, and HK in 2000 to 2009 were identified. The total number of articles, clinical trials, randomized controlled trials (RCTs), impact factors (IF), citations, and articles published in the top 10 orthopaedic journals were analyzed.

RESULTS

A total of 1878 published articles in 2000 to 2009 were broken down as follows: ML (607), TW (865), and HK (406). There was a significant increase in published articles for ML and TW from 2000 to 2009. The number of published articles from ML exceeded the total sum of articles from TW and HK in 2009. The accumulated IF of articles from TW (1751.91) was higher than that from ML (1054.67) and HK (708.25). TW had the highest average IF (2.025), followed by ML (1.902) and HK (1.862). The total citations of published articles in 2000 to 2009 from TW (4759) were higher than those for HK (2276) and ML (1751). The highest average citation of each article was from HK (5.784), followed by TW (5.720) and ML (3.051). TW published 339 articles in 10 high-impact journals, whereas ML and HK published 267 and 154 articles, respectively.

DISCUSSION

Chinese researchers in the field of orthopaedics have been more and more active in the global orthopaedic community during the past 10 years. ML seems to have caught up to HK and TW in respect to research output.