Family history and its association to curve size and treatment in 1,463 patients with idiopathic scoliosis

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.

Adolescent Idiopathic Scoliosis Minimum Data Set: Towards Standardization of Data Elements in History and Physical Examination

INTRODUCTION

Nonoperative care represents a cornerstone of adolescent idiopathic scoliosis (AIS) management, although no consensus exists for a minimal data set. We aimed to determine a consensus in critical data points to obtain during clinical AIS visits.

METHODS

A REDCap-based survey was distributed to Pediatric Orthopedic Society of America (POSNA), Pediatric Spine Study Group (PSSG), and International Society on Scoliosis Orthopedic and Rehabilitation Treatment (SOSORT). Respondents ranked the importance of data points in history, physical examination, and bracing during AIS visits.  Results: One hundred eighty-one responses were received (26% response rate), of which 86% were physicians and 14% were allied health professionals. About 80% of respondents worked at pediatric hospitals or pediatric spaces within adult hospitals, and 82% were academic, with the majority (57%) seeing 150+ unique AIS patients annually. Most respondents recommended six-month follow-up for patients under observation (60%) and bracing (54%). Most respondents (75%) considered family history and pain important (69%), with the majority (69%) asking about pain at every visit. Across all time points, Adam's forward bend test, shoulder level, sagittal contour, trunk shift, and curve stiffness were all considered critically important (>60%). At the first visit, scapular prominence, leg lengths, motor and neurological examination, gait, and iliac crest height were also viewed as critical. At the preoperative visit, motor strength and scapular prominence should also be documented. About 39% of respondents use heat sensors to monitor bracing compliance, and average brace wear since the prior visit was considered the most important (85%) compliance data point.

CONCLUSIONS

This study establishes recommendations for a 19-item minimum data set for clinical AIS evaluation, including history, physical exam, and bracing, to allow for future multicenter registry-based studies.

Association between genetic polymorphisms and risk of adolescent idiopathic scoliosis in case-control studies: a systematic review

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥10° with rotation. Approximately 2%-3% of children across populations are affected with AIS, and this condition is responsible for ~$3 billion in costs within the USA. Although AIS is believed to have a strong genetic contribution, clinical translation of identified genetic variants has stalled.

METHODS

The databases MEDLINE (via PubMed), Embase, Google Scholar and Ovid MEDLINE were searched and limited to articles in English. Title and abstract, full-text and data extraction screening was conducted through Covidence, followed by data transfer to a custom REDCap database. Studies containing variant-level data using genome-wide methodology as well as validation studies of genome-wide methods were considered. Quality assessment was conducted using Q-Genie.

RESULTS

33 studies were included, including 9 genome-wide association studies, 4 whole exome sequencing and 20 validation studies. Combined, these studies included data from >35,000 cases and >67,000 controls, not including validation cohorts. Additionally, results from six meta-analyses containing novel cohorts were also reported. All included study cohorts were from populations of primarily East Asian or Caucasian descent. Quality assessment found that overall study quality was high and control group selection was moderate. The highest number of reported associations were in single nucleotide polymorphisms (SNPs) in or near LBX1, LBX1-AS1, GPR126/ADGRG6 or BNC2.

CONCLUSION

AIS risk may be influenced by specific SNPs, particularly those in/near LBX1 and GPR126. Translatability of study findings is unknown due to an underrepresentation of most ethnic groups as well as few identified genome-wide studies. Further studies may benefit from increased cohort diversity and thorough evaluation of control cohort groups.

A New Clinical Tool for Scoliosis Risk Analysis: Scoliosis Tele-Screening Test

STUDY DESIGN

Methodological, observational clinical study.

PURPOSE

This study aimed to develop a virtual screening test to detect scoliosis risk initially by parents without the need for medical visit during the coronavirus disease 2019 pandemic.

OVERVIEW OF LITERATURE

The scoliosis screening program has been implemented to early detect scoliosis. Unfortunately, access to health professionals was limited during the pandemic. However, during this time, interest in telemedicine has increased remarkably. Recently, mobile applications related to postural analysis were developed, but none permits evaluation by parents.

METHODS

Researchers developed the Scoliosis Tele-Screening Test (STS-Test), which included drawing-based images of body asymmetries, to assess the scoliosis-associated risk factors. The STS-Test was shared on social networks, allowing the parents to evaluate their children. After test completion, the risk score was generated automatically, and children with medium and high risks were then advised for medical consultation for further evaluation. The test accuracy and consistency between the clinician and parents were also analyzed.

RESULTS

Of the 865 tested children, 358 (41.4%) consulted clinicians to confirm their STS-Test results. Scoliosis was then confirmed in 91 children (25.4%). The parents were able to detect asymmetry in 50% of the lumbar/thoracolumbar curvatures and 82% of the thoracic curvatures. In addition, the forward bend test revealed favorable agreement between parents and clinicians (r =0.809, p<0.0005). Internal consistency of the esthetic deformities domain in the STS-Test was also excellent (α=0.901). This tool was 94.97% accurate, 83.51% sensitive, and 98.87% specific.

CONCLUSIONS

The STS-Test is a new parent-friendly, virtual, cost-effective, result-oriented, and reliable tool for scoliosis screening. It allows parents to actively participate in the early detection of scoliosis by screening their children for the risk of scoliosis periodically without the need to visit the health institution.

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

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

The Hereditary Nature of Adolescent Spinal Deformities: A Study of Over 600,000 Adolescents

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

We designed this study to investigate the risk for spinal deformity among individuals whose parents had a spinal deformity.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis and Scheuermann kyphosis (SK) are common adolescent spinal deformities (ASD) with a significant impact on public health. Timely treatment with bracing is effective in halting or slowing the progression of these deformities. However, screening healthy adolescents for spinal deformities remains debatable. While the leading medical organizations endorse contradictory positions regarding the screening of the general population, there is a consensus that screening of targeted population should be considered. Due to their genetic predisposition, adolescents whose parents suffer from a spinal deformity may be candidates for targeted screening.

METHODS

We conducted a nationwide, population-based study of 611,689 Israeli adolescents, aged 16 to 19 years old, who were screened for spinal deformities between the years 2000 and 2019. The data for this study were derived from a central database containing medical records of all adolescents who were examined preliminary to mandatory military service. In our study, ASD were strictly defined by plain x-ray.

RESULTS

Compared with adolescents of whose parents did not have a spinal deformity, the odds ratios (OR) for ASD among adolescents whose father, mother, or both parents had spinal deformity were 1.46, 1.74, and 2.58, respectively. These ratios were consistent in multivariate models.

CONCLUSION

We have found a considerable increased risk for adolescent spinal deformities among adolescents whose parents suffered from spinal deformities. We believe that our findings should serve the leading medical organizations when considering the screening of targeted populations.

LEVEL OF EVIDENCE

4.

Genetic variants associated with the occurrence and progression of adolescent idiopathic scoliosis: a systematic review protocol

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥ 10° with rotation. Approximately 2-3% of children in most populations are affected with AIS, and this condition is responsible for approximately $1.1 billion in surgical costs to the US healthcare system. Although a genetic factor for AIS has been demonstrated for decades, with multiple potentially contributory loci identified across populations, treatment options have remained limited to bracing and surgery.

METHODS

The databases MEDLINE (via PubMed), Embase, Google Scholar, and Ovid MEDLINE will be searched and limited to articles in English. We will conduct title and abstract, full-text, and data extraction screening through Covidence, followed by data transfer to a custom REDCap database. Quality assessment will be confirmed by multiple reviewers. Studies containing variant-level data (i.e., GWAS, exome sequencing) for AIS subjects and controls will be considered. Outcomes of interest will include presence/absence of AIS, scoliosis curve severity, scoliosis curve progression, and presence/absence of nucleotide-level variants. Analyses will include odds ratios and relative risk assessments, and subgroup analysis (i.e., males vs. females, age groups) may be applied. Quality assessment tools will include GRADE and Q-Genie for genetic studies.

DISCUSSION

In this systematic review, we seek to evaluate the quality of genetic evidence for AIS to better inform research efforts, to ultimately improve the quality of patient care and diagnosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration #CRD42021243253.

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.

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.

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.

IS (Idiopathic Scoliosis) etiology: Multifactorial genetic research continues. A systematic review 1950 to 2017

Objective

IS (idiopathic scoliosis) is a common spinal condition occurring in otherwise completely healthy adolescents. The root cause of IS remains unclear. This systematic review will focus on an update of genetic factors and IS etiology. Though it is generally accepted that the condition is not due to a single gene effect, etiology studies continue looking for a root cause including genetic variants. Though susceptibility from multiple genetic components is plausible based on known family history data, the literature remains unclear regarding multifactorial genetic influences. The objective of this study was to critically evaluate the evidence behind genetic causes (not single gene) of IS through a systematic review and strength-of-study analysis of existing genetic and genome-wide association studies (GWAS). We used the protocol of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Methods

PubMed was searched for the terms IS, scoliotic, spinal curve, genetic, gene, etiology, polymorphisms. Articles were assessed for risk-of-bias. Level-of-evidence grading was completed via Oxford Centre for Evidence-Based Medicine criteria. The assessment scores factor strength of a study in determining a positive or negative association to a gene etiology.

Results

After screening of 36 eligible papers, 8 relevant studies met inclusion criteria at this time, 3 were in favor of a genetic factor for IS, whereas 5 studies were against it.

Conclusion

Based on the literature analyzed, there is moderate evidence with a low risk-of-bias that does not clarify a genetic cause of IS. The 2 studies in favor of a genetic etiology were completed in homogeneous populations, limiting their generalizability. Relying on a genetic etiology alone for IS may over simplify its multifactorial nature and limit appreciation of other influences.

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.

Genome-wide meta-analysis and replication studies in multiple ethnicities identify novel adolescent idiopathic scoliosis susceptibility loci

Adolescent idiopathic scoliosis (AIS) is the most common musculoskeletal disorder of childhood development. The genetic architecture of AIS is complex, and the great majority of risk factors are undiscovered. To identify new AIS susceptibility loci, we conducted the first genome-wide meta-analysis of AIS genome-wide association studies, including 7956 cases and 88 459 controls from 3 ancestral groups. Three novel loci that surpassed genome-wide significance were uncovered in intragenic regions of the CDH13 (P-value_rs4513093 = 1.7E-15), ABO (P-value_ rs687621 = 7.3E-10) and SOX6 (P-value_rs1455114 = 2.98E-08) genes. Restricting the analysis to females improved the associations at multiple loci, most notably with variants within CDH13 despite the reduction in sample size. Genome-wide gene-functional enrichment analysis identified significant perturbation of pathways involving cartilage and connective tissue development. Expression of both SOX6 and CDH13 was detected in cartilage chondrocytes and chromatin immunoprecipitation sequencing experiments in that tissue revealed multiple HeK27ac-positive peaks overlapping associated loci. Our results further define the genetic architecture of AIS and highlight the importance of vertebral cartilage development in its pathogenesis.

Quality of Life in Males and Females With Idiopathic Scoliosis

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To describe quality of life in males and females with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Idiopathic scoliosis is a three-dimensional deformity affecting the growing spine. The prevalence of larger curves, requiring treatment, is higher in females.

METHODS

This cross-sectional study comprised 1519 individuals with idiopathic scoliosis (211 males) with a mean (SD) age of 35.3 (14.9) years. They all answered the Scoliosis Research Society 22 revised (SRS-22r) questionnaire and EuroQol 5-dimension-index (EQ-5D). Five hundred twenty eight were surgically treated (78 males), 535 were brace treated (50 males), and 456 were untreated (83 males). The SRS-22r subscore (excluding the satisfaction domain), the SRS-22r domains and the EQ-5D index score were calculated. Subgroup analyses based on treatment and age were performed. Statistical comparisons were performed using analysis of covariance with adjustments for age and treatment. A P-value less than 0.05 was considered as statistical significant.

RESULTS

The mean (SD) SRS-22r subscore was 4.19 (0.61) in males and 4.05 (0.61) in females (P = 0.010). The males had higher scores on the SRS-22r domains function (4.56 vs. 4.42), pain (4.20 vs. 4.00), and mental health (4.14 vs. 3.92) (all P < 0.05). The mean (SD) EQ-5D index score was 0.85 (0.22) for males and 0.81 (0.21) for females (P = 0.10). There were minor differences when comparing males and females in treatment and age groups, but both treated and untreated groups had reduced quality of life compared with the national norms.

CONCLUSION

When compared with females, males with idiopathic scoliosis tend to have slightly higher scores in the scoliosis specific SRS-22r but not in the generic quality of life measurement EQ-5D. Quality of life is overall similar between males and females in treatment and age groups, but reduced in comparison with the general population.

LEVEL OF EVIDENCE

3.

A multi-ethnic meta-analysis confirms the association of rs6570507 with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common type of spinal deformity and has a significant genetic background. Genome-wide association studies (GWASs) identified several susceptibility loci associated with AIS. Among them is a locus on chromosome 6q24.1 that we identified by a GWAS in a Japanese cohort. The locus is represented by rs6570507 located within GPR126. To ensure the association of rs6570507 with AIS, we conducted a meta-analysis using eight cohorts from East Asia, Northern Europe and USA. The analysis included a total of 6,873 cases and 38,916 controls and yielded significant association (combined P = 2.95 × 10^-20; odds ratio = 1.22), providing convincing evidence of the worldwide association between rs6570507 and AIS susceptibility. In silico analyses strongly suggested that GPR126 is a susceptibility gene at this locus.

Health-Related Quality of Life in Adulthood in Untreated and Treated Individuals with Adolescent or Juvenile Idiopathic Scoliosis

BACKGROUND

Health-related quality of life in adults with idiopathic scoliosis diagnosed before maturity has been reported to be similar between brace-treated and surgically treated individuals. The aim of this study was to compare health-related quality of life in untreated, brace-treated, and surgically treated adults with idiopathic scoliosis diagnosed before skeletal maturity. Subgroup analyses were performed on the basis of age at the time of the study, age of onset, surgical characteristics, and curve magnitude.

METHODS

We included 1,187 adults with juvenile or adolescent idiopathic scoliosis with a mean age (and standard deviation) of 38.8 ±12.7 years. Of these, 347 were untreated, 459 had been brace-treated, and 381 had been surgically treated. The Scoliosis Research Society-22r (SRS-22r) and EuroQol 5-Dimensions (EQ-5D) were used. Statistical analyses were performed using analysis of covariance.

RESULTS

The mean SRS-22r subscore was 4.15 ± 0.59 points for the untreated group, 4.10 ± 0.57 points for the previously braced group, and 4.01 ± 0.64 points for the surgically treated group (p = 0.007 adjusted for age and sex). The EQ-5D index was 0.82 ± 0.20 for the untreated group, 0.82 ± 0.20 for the previously brace-treated group, and 0.79 ± 0.24 for the surgically treated group (p = 0.026, adjusted for age and sex). Brace cessation was at the mean age of 16.2 ± 1.5 years, and the surgical procedure had been performed at the mean age of 15.3 ± 2.1 years. A more caudal fusion was associated with a lower SRS-22r subscore and EQ-5D index. No differences were observed when comparing individuals with juvenile or adolescent onset scoliosis (all p > 0.05).

CONCLUSIONS

Untreated adults with idiopathic scoliosis had similar health-related quality of life to previously brace-treated individuals, and they had marginally higher health-related quality of life compared with surgically treated individuals. Therefore, both surgical and brace treatments for idiopathic scoliosis could be considered successful from a health-related quality-of-life point of view in adulthood. The age of onset of idiopathic scoliosis does not seem to influence quality of life in adulthood.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

An international meta-analysis confirms the association of BNC2 with adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity with the prevalence of approximately 3%. We previously conducted a genome-wide association study (GWAS) using a Japanese cohort and identified a novel locus on chromosome 9p22.2. However, a replication study using multi-population cohorts has not been conducted. To confirm the association of 9p22.2 locus with AIS in multi-ethnic populations, we conducted international meta-analysis using eight cohorts. In total, we analyzed 8,756 cases and 27,822 controls. The analysis showed a convincing evidence of association between rs3904778 and AIS. Seven out of eight cohorts had significant P value, and remaining one cohort also had the same trend as the seven. The combined P was 3.28 × 10⁻¹⁸ (odds ratio = 1.19, 95% confidence interval = 1.14–1.24). In silico analyses suggested that BNC2 is the AIS susceptibility gene in this locus.

Scoliosis severity does not impact the risk of scoliosis in family members

Does scoliosis severity increase scoliosis risk or severity in relatives? In a cohort of 1257 severe idiopathic scoliosis patients, the percentage with at least one affected relative was compared across the categories of patient sex, major curve severity (Cobb angle), and treatment method. In total, 138 (11%) of 1257 patients had at least one affected first-degree relative and 59 (5%) had at least one affected second-degree relative. As expected, males were more likely to have affected first-degree relatives than females (18 vs. 10% with a risk difference of -0.0864) [95% confidence interval (CI): -0.14 to -0.03; P=0.0002]. However, the major curve severity of the patient (<25°, 25°-49°, and ≥50°) did not impact the prevalence of having at least one affected relative (P=0.69). Surgically treated patients had no greater risk than nonsurgically treated patients of having either an affected relative or a surgically treated relative [11 vs. 11% (odds ratio: 0.912; 95% CI: 0.640-1.299, P=0.61), 6 vs. 5% (OR: 0.788; 95% CI: 0.485-1.280, P=0.34), respectively]. Therefore, our data suggest that scoliosis severity does not independently influence the risk of either scoliosis or its severity in family members.

Etiological Theories of Adolescent Idiopathic Scoliosis: Past and Present

Adolescent idiopathic scoliosis is one of the most common spinal deformities, yet its cause is unknown. Various theories look to biomechanical, neuromuscular, genetic, and environmental origins, yet our understanding of scoliosis etiology is still limited. Determining the cause of a disease is crucial to developing the most effective treatment. Associations made with scoliosis do not necessarily point to causality, and it is difficult to determine whether said associations are primary (playing a role in development) or secondary (develop as a result of scoliosis). Scoliosis is a complex condition with highly variable expression, even among family members, and likely has many causes. These causes could be similar among homogenous groups of AIS patients, or they could be individual. Here, we review the most prevalent theories of scoliosis etiology and recent trends in research.

Neck and back problems in adults with idiopathic scoliosis diagnosed in youth: an observational study of prevalence, change over a mean four year time period and comparison with a control group

BACKGROUND

The knowledge is sparse concerning neck problems in patients with idiopathic scoliosis. This is an observational study including a control group which aims to describe the prevalence of neck problems and the association with back problems among adult individuals with and without idiopathic scoliosis.

METHODS

One thousand sixty-nine adults with a mean age of 40 years, diagnosed with idiopathic scoliosis in youth, answered a questionnaire on neck and back problems. Eight hundred seventy of these answered the same questionnaire at a second occasion in a mean of 4 years later. Comparisons were made with a cross-sectional population-based survey of 158 individuals. Statistical analyses were made with logistic regression or analysis of variance, adjusted for age, smoking status, and sex.

RESULTS

Individuals with scoliosis were previously untreated (n = 374), brace treated (n = 451), or surgically treated (n = 244). Of the individuals with scoliosis, 42% (n = 444) had neck problems compared to 20% (n = 32) of the controls (p = 0.001). The prevalence of neck problems was not affected by the type of treatment (p = 0.67) or onset of scoliosis; juvenile (n = 159) or adolescent (n = 910; p = 0.68). Neck and/or back problems were experienced by 72% of the individuals with scoliosis and 37% of the controls (p < 0.001). Of the individuals with scoliosis having neck problems, 81% also reported back problems, compared to 59% of the individuals in the control group (p < 0.001). The prevalence of neck and back problems was similar at the second survey.

CONCLUSIONS

Neck problems are more prevalent and more often coexist with back problems in individuals with idiopathic scoliosis than in controls. The majority of individuals have persisting problems over time.

Concordance for curve type in idiopathic scoliosis among family members

OBJECTIVE:

To evaluate the concordance for the curve pattern, side and levels of the superior apical vertebrae, apex and inferior apical vertebrae of curves in patients and their relatives with idiopathic scoliosis.

METHODS:

Concordance according to the Lenke classification for curve pattern, side and levels of the superior apical vertebrae, apex and inferior apical vertebrae were evaluated comparative and prospectively in 243 pairs of patients and respective relatives with idiopathic scoliosis.

RESULTS:

The family concordance for the curve pattern and side was 51.4% (125 pairs). Among these pairs, the concordance of the levels of the vertebrae was 91.2% (114 pairs). The concordance rate for the curve pattern and side between parents/children was 51.6% and between siblings was 50.0% (p-value= 0.411). The concordance rates of the levels of vertebrae were 86.8% and 95.1%, respectively (p-value = 0.219).

CONCLUSION:

Curve shape in idiopathic scoliosis is related to family and degree of kinship, since the data showed a high concordance for the curve pattern, side and levels of the apical vertebrae and apex between patients and relatives with this deformity. The concordance was higher in those with a closer degree of kinship.Level of Evidence II, Lesser Quality Prospective Study.

Adults With Idiopathic Scoliosis Diagnosed at Youth Experience Similar Physical Activity and Fracture Rate as Controls

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To describe physical activity level and fracture rates in adults with idiopathic scoliosis, diagnosed before maturity, and to compare with a control group.

SUMMARY OF BACKGROUND DATA

A previous study found a lower level of sporting activities in adults treated for idiopathic scoliosis compared with controls. Other studies have shown a lower bone mass in adults with idiopathic scoliosis compared with controls.

METHODS

One thousand two hundred seventy-eight adults (aged 18-71 yr) with idiopathic scoliosis and 214 controls (aged 18-70 yr) were included and answered the International Physical Activity Questionnaire - Short Form (IPAQ-SF) and questions about previous fractures. The three scoliosis treatment groups (untreated n = 360, brace n = 460, and surgically treated n = 458) were compared. Furthermore, a comparison based on onset (juvenile n = 169 or adolescent n = 976) was performed. Achieved weekly moderate activity level and metabolic equivalent task (MET) minutes/week were assessed for patients and controls. Statistical comparisons were made with analysis of covariance with adjustments for age, body mass index, and sex.

RESULTS

The proportion achieving weekly moderate activity level was 962 out of 1278 for individuals with idiopathic scoliosis (75%) and 157 out of 214 (73%) for controls (P = 0.40). The scoliosis patients reported 2016 MET-minutes/week (median value) and the controls 2456 (P = 0.06). Fracture rates did not differ (P = 0.72). Fewer surgically treated individuals achieved moderate activity level (P = 0.046) compared with the untreated and the previously braced individuals. No difference was seen regarding MET-minutes/week (P = 0.86). No differences were seen between individuals with a juvenile onset compared with individuals with an adolescent onset (all P ≥ 0.05).

CONCLUSION

Adults with idiopathic scoliosis have similar physical activity level and do not sustain more fractures compared with controls. Adults with surgically treated idiopathic scoliosis have slightly lower physical activity level than previously braced and untreated patients. Onset of idiopathic scoliosis does not affect physical activity level.

LEVEL OF EVIDENCE

2.

Genetics and pathogenesis of idiopathic scoliosis

Idiopathic scoliosis (IS), the most common spinal deformity, affects otherwise healthy children and adolescents during growth. The aetiology is still unknown, although genetic factors are believed to be important. The present review corroborates the understanding of IS as a complex disease with a polygenic background. Presumably IS can be due to a spectrum of genetic risk variants, ranging from very rare or even private to very common. The most promising candidate genes are highlighted.

Candidate gene analysis and exome sequencing confirm LBX1 as a susceptibility gene for idiopathic scoliosis

BACKGROUND CONTEXT

Idiopathic scoliosis is a spinal deformity affecting approximately 3% of otherwise healthy children or adolescents. The etiology is still largely unknown but has an important genetic component. Genome-wide association studies have identified a number of common genetic variants that are significantly associated with idiopathic scoliosis in Asian and Caucasian populations, rs11190870 close to the LBX1 gene being the most replicated finding.

PURPOSE

The aim of the present study was to investigate the genetics of idiopathic scoliosis in a Scandinavian cohort by performing a candidate gene study of four variants previously shown to be associated with idiopathic scoliosis and exome sequencing of idiopathic scoliosis patients with a severe phenotype to identify possible novel scoliosis risk variants.

STUDY DESIGN

This was a case control study.

PATIENT SAMPLE

A total of 1,739 patients with idiopathic scoliosis and 1,812 controls were included.

OUTCOME MEASURE

The outcome measure was idiopathic scoliosis.

METHODS

The variants rs10510181, rs11190870, rs12946942, and rs6570507 were genotyped in 1,739 patients with idiopathic scoliosis and 1,812 controls. Exome sequencing was performed on pooled samples from 100 surgically treated idiopathic scoliosis patients. Novel or rare missense, nonsense, or splice site variants were selected for individual genotyping in the 1,739 cases and 1,812 controls. In addition, the 5'UTR, noncoding exon and promoter regions of LBX1, not covered by exome sequencing, were Sanger sequenced in the 100 pooled samples.

RESULTS

Of the four candidate genes, an intergenic variant, rs11190870, downstream of the LBX1 gene, showed a highly significant association to idiopathic scoliosis in 1,739 cases and 1,812 controls (p=7.0×10(-18)). We identified 20 novel variants by exome sequencing after filtration and an initial genotyping validation. However, we could not verify any association to idiopathic scoliosis in the large cohort of 1,739 cases and 1,812 controls. We did not find any variants in the 5'UTR, noncoding exon and promoter regions of LBX1.

CONCLUSIONS

Here, we confirm LBX1 as a susceptibility gene for idiopathic scoliosis in a Scandinavian population and report that we are unable to find evidence of other genes of similar or stronger effect.

Prevalence of Back Problems in 1069 Adults With Idiopathic Scoliosis and 158 Adults Without Scoliosis

STUDY DESIGN

Multicenter case-control study.

OBJECTIVE

To investigate the prevalence of back problems in adults with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Information on the prevalence of back problems in adults with idiopathic scoliosis is scarce, especially in untreated individuals, males, and individuals with an age at the onset of scoliosis of less than 10 years.

METHODS

A total of 1069 individuals with idiopathic scoliosis and 158 individuals without scoliosis, all aged 20 to 65 years, answered a questionnaire on back problems. Individuals with scoliosis were diagnosed between ages 4 and 20 years and any treatment was terminated before the age of 20 years. Logistic regression or analysis of variance was used for group comparisons.

RESULTS

Mean (SD) age at the time of investigation in individuals with scoliosis (123 males and 946 females) was 41 (9) years, and in individuals without scoliosis (75 males and 83 females) 45 (13) years. Three hundred seventy-four individuals with scoliosis were untreated, 451 had been brace treated, and 244 were surgically treated. The mean prevalence of back problems was 64% in the individuals with scoliosis and 29% in the individuals without scoliosis (P < 0.001). Among the untreated individuals with scoliosis, 69% reported back problems; among the brace treated, 61%; and among the surgically treated, 64% (P = 0.06). When comparing females and males with scoliosis, and individuals with juvenile and adolescent scoliosis, there were no statistically significant differences in the prevalence of back problems (P = 0.10 and P = 0.23, respectively).

CONCLUSION

Adults with idiopathic scoliosis have a higher prevalence of back problems than individuals without scoliosis. Treatment, sex, and juvenile or adolescent onset of diagnosis was not related to the prevalence of back problems in adulthood.

LEVEL OF EVIDENCE

2.