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

Current biomechanical theories on the etiopathogenesis of idiopathic scoliosis

PURPOSE

There is great controversy about the etiologic origin of adolescent idiopathic scoliosis. Multiple theories have been suggested, including metabolic aspects, endocrine dysfunction, neurological central abnormalities, genetic predisposition and epigenetic factors involved in the development of scoliosis. However, there has always been speculations based on human biomechanical behavior.

METHODS

In this article, we performed a literature review on the biomechanical traits of human posture, and the proposed theories that explain the special characteristics present in idiopathic scoliosis.

RESULTS

The current theory on the etiopathogeneis of AIS suggests that dorsally directed shear loads acting on a preexisting axial plane rotation, in a posteriorly inclined sagittal plane of a growing patient, together with disc maturation, collagen quality at this phase of development and immaturity of proprioception, is the perfect scenario to spark rotational instability and create the three-dimensional deformity that defines idiopathic scoliosis.

CONCLUSION

The unique spinal alignment of human bipedalism, gravity and muscle forces acting straight above the pelvis to preserve an upright balance, and the instability of the soft tissue in a period of growth development, is an appealing cocktail to try to explain the genesis of this condition in humans.

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

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

Predicting Progression in Adolescent Idiopathic Scoliosis at the First Visit by Integrating 2D Imaging and 1D Clinical Information

STUDY DESIGN

Retrospective observational study.

OBJECTIVES

The prediction of curve progression in patients with adolescent idiopathic scoliosis (AIS) remains an unresolved area in orthopedic surgery. To make a rapid meaningful prediction, easily accessible multi-dimensional data at the patient's first consultation should be used. Current studies use clinical growth parameters and numerical values extracted from radiographs to compile a predictive model, leaving out the radiographs themselves. Such practice inevitably wastes a lot of information. Thus, this study aims to create a neural network that can predict AIS progression among patients with curves indicated for bracing by integrating both one-dimensional (1D) clinical and two-dimensional (2D) radiological data collected at the patient's first visit in a fully automated manner.

METHODS

513 idiopathic scoliosis patients indicated for and managed with bracing orthosis were recruited. After exclusion, 463 patients were included in deep learning analysis. Processed first-visit growth parameters and posteroanterior radiographs are used as training inputs and the curve progression outcomes obtained in follow ups are used as binary training outputs. The CapsuleNet architecture was modified and trained accordingly to make a prediction.

RESULTS

The final model achieved 90% sensitivity with an overall accuracy of 73.9% in the prediction of AIS in-brace curve progression by using first-visit multi-dimensional data, outperforming conventional convolutional neural networks.

CONCLUSIONS

This first-ever multidimensional-input model shows promise in serving as a screening tool for AIS in-brace curve progression. The incorporation of such a model into routine AIS diagnostic pipeline can assist orthopedics clinicians in personalizing the most appropriate management for each patient.

Scoliosis in osteogenesis imperfecta: identifying the genetic and non-genetic factors affecting severity and progression from longitudinal data of 290 patients

BACKGROUND

Scoliosis is widely prevalent among osteogenesis imperfecta (OI) patients, and is progressive with age. However, factors affecting scoliosis in OI are not well known.

METHODS

We retrospectively retrieved longitudinal radiographic and clinical records of consecutive OI patients seeking treatments at our hospital from 2014 to 2022, graded their pre-operative spinal conditions into four outcome groups, estimated their progression rates, and descriptively and inferentially analyzed the genetic and non-genetic factors that may affect the outcomes and progression rates.

RESULTS

In all, 290 OI patients met the inclusion criteria, where 221 had genetic records. Of these 221, about 2/3 had mutations in COL1A1 or COL1A2, followed by mutations in WNT1 (9.0%), IFITM5 (9.0%) and other OI risk genes. With an average age of 12.0 years (interquartile range [IQR] 6.9-16.1), 70.7% of the cohort had scoliosis (Cobb angle > 10°), including 106 (36.5%) mild (10°-25°), 40 (13.8%) moderate (25°-50°), and 59 (20.3%) severe (> 50°) scoliosis patients. Patients with either COL1A1 and COL1A2 were strongly biased toward having mild or no scoliosis, whereas patients with mutations in IFITM5, WNT1 and other recessive genes were more evenly distributed among the four outcome grades. Lower-limb discrepancy, bone mineral density (BMD) and age of first drug used were all significantly correlated with severity outcomes. Using multivariate logistic regression, we estimated that each year older adds an odds ratio of 1.13 (95% confidence interval [CI] 1.07-1.2) in progression into advanced stages of scoliosis. We estimated a cohort-wide progression rate of 2.7 degrees per year (95% CI 2.4-3.0). Early-onset patients experienced fast progressions during both infantile and adolescent stages. Twenty-five of the 59 (42.8%) patients with severe scoliosis underwent spinal surgeries, enjoying an average Cobb angle reduction of 33° (IQR 23-40) postoperatively.

CONCLUSION

The severity and progression of scoliosis in osteogenesis imperfecta were affected by genetic factors including genotypes and mutation types, and non-genetic factors including age and BMD. As compared with COL1A1, mutations in COL1A2 were less damaging while those on IFITM5 and other recessive genes conferred damaging effects. Progression rates were the fastest in the adolescent adult age-group.

Prediction of future curve angle using prior radiographs in previously untreated idiopathic scoliosis: natural history from age 6 to after the end of growth (SOSORT 2022 award winner)

PURPOSE

Treatment selection for idiopathic scoliosis is informed by the risk of curve progression. Previous models predicting curve progression lacked validation, did not include the full growth/severity spectrum or included treated patients. The objective was to develop and validate models to predict future curve angles using clinical data collected only at, or both at and prior to, an initial specialist consultation in idiopathic scoliosis.

METHODS

This is an analysis of 2317 patients with idiopathic scoliosis between 6 and 25 years old. Patients were previously untreated and provided at least one prior radiograph prospectively collected at first consult. Radiographs were re-measured blinded to the predicted outcome: the maximum Cobb angle on the last radiograph while untreated. Linear mixed-effect models were used to examine the effect of data from the first available visit (age, sex, maximum Cobb angle, Risser, and curve type) and from other visits while untreated (maximum Cobb angle) and time (from the first available radiograph to prediction) on the Cobb angle outcome. Interactions of the first available angle with time, of time with sex, and time with Risser were also tested.

RESULTS

We included 2317 patients (83% of females) with 3255 prior X-rays where 71% had 1, 21.1% had 2, and 7.5% had 3 or more. Mean age was 13.9 ± 2.2yrs and 81% had AIS. Curve types were: 50% double, 26% lumbar/thoracolumbar-lumbar, 16% thoracic, and 8% other. Cobb angle at the first available X-ray was 20 ± 10° (0-80) vs 29 ± 13° (6-122) at the outcome visit separated by 28 ± 22mths. In the model using data at and prior to the specialist consult, larger values of the following variables predicted larger future curves: first available Cobb angle, Cobb angle on other previous X-ray, and time (with Time2 and Time3) to the target prediction. Larger values on the following variables predicted a smaller future Cobb angle: Risser and age at the first available X-ray, time*Risser and time*female sex interactions. Cross-validation found a median error of 4.5o with 84% predicted within 10°. Similarly, the model using only data from the first specialist consult had a median error of 5.5o with 80% of cases within 10° and included: maximum Cobb angle at first specialist consult, Time, Time2, age, curve type, and both interactions.

CONCLUSIONS

The models can help clinicians predict how much curves would progress without treatment at future timepoints of their choice using simple variables. Predictions can inform treatment prescription or show families why no treatment is recommended. The nonlinear effects of time account for the rapid increase in curve angle at the beginning of growth and the slowed progression after maturity. These validated models predicted future Cobb angle with good accuracy in untreated idiopathic scoliosis over the full growth spectrum.

Imaging Methods to Quantify the Chest and Trunk Deformation in Adolescent Idiopathic Scoliosis: A Literature Review

Background context: Scoliosis is a three-dimensional deformity of the spine with the most prevalent type being adolescent idiopathic scoliosis (AIS). The rotational spinal deformation leads to displacement and deformation of the ribs, resulting in a deformity of the entire chest. Routine diagnostic imaging is performed in order to define its etiology, measure curve severity and progression during growth, and for treatment planning. To date, all treatment recommendations are based on spinal parameters, while the esthetic concerns and cardiopulmonary symptoms of patients are mostly related to the trunk deformation. For this reason, there is a need for diagnostic imaging of the patho-anatomical changes of the chest and trunk in AIS. Aim: The aim of this review is to provide an overview, as complete as possible, of imaging modalities, methods and image processing techniques for assessment of chest and trunk deformation in AIS. Methods: Here, we present a narrative literature review of (1) image acquisition techniques used in clinical practice, (2) a description of various relevant methods to measure the deformity of the thorax in patients with AIS, and (3) different image processing techniques useful for quantifying 3D chest wall deformity. Results: Various ionizing and non-ionizing imaging modalities are available, but radiography is most widely used for AIS follow-up. A disadvantage is that these images are only acquired in 2D and are not effective for acquiring detailed information on complex 3D chest deformities. While CT is the gold standard 3D imaging technique for assessment of in vivo morphology of osseous structures, it is rarely obtained for surgical planning because of concerns about radiation exposure and increased risk of cancer during later life. Therefore, different modalities with less or without radiation, such as biplanar radiography and MRI are usually preferred. Recently, there have been advances in the field of image processing for measurements of the chest: Anatomical segmentations have become fully automatic and deep learning has been shown to be able to automatically perform measurements and even outperform experts in terms of accuracy. Conclusions: Recent advancements in imaging modalities and image processing techniques make complex 3D evaluation of chest deformation possible. Before introduction into daily clinical practice, however, there is a need for studies correlating image-based chest deformation parameters to patient-reported outcomes, and for technological advancements to make the workflow cost-effective.

Predictors of Clinically Meaningful Results of Bracing in a Large Cohort of Adolescents with Idiopathic Scoliosis Reaching the End of Conservative Treatment

BACKGROUND

We need good outcome predictors to maximize the treatment efficiency of adolescents with idiopathic scoliosis (AIS). The in-brace correction has shown an important predictive effect on brace failure, while the influence of other variables is still debated. We aimed to identify new outcome predictors from a big prospective database of AIS.

METHODS

Design: Retrospective analysis of prospectively collected data.

INCLUSION CRITERIA

AIS between 21 and 45°, Risser 0-2, brace prescription during the observation, treatment conclusion. All of the participants followed a personalized conservative approach according to the SOSORT Guidelines.

OUTCOMES

End of growth below 30°-40°-50°. The regression model included age, BMI, Cobb angle, ATR, TRACE score, real brace wear (RBW), and in-brace correction (IBC).

RESULTS

A total of 1050 patients, 84% females, ages 12.1 ± 1.1, 28.2 ± 7.9° Cobb. IBC increased by 30%, 24%, and 23% the odds of ending treatment below 30°, 40°, and 50°, respectively. The OR did not change after the covariate adjustment. Cobb angle and ATR at the start also showed a predictive effect.

CONCLUSIONS

The systematic evaluation of IBC in clinics is useful for individuating the patient response to brace treatment more accurately, even in relation to the Cobb angle and ATR degrees at the start. Further studies are needed to increase the knowledge on predictors of AIS treatment results.

Advancing Use of DEXA Scans to Quantitatively and Qualitatively Evaluate Lateral Spinal Curves, for Preliminary Identification of Adolescent Idiopathic Scoliosis

Dual-energy X-ray absorptiometry (DEXA) scan is an emerging screening method for identifying likely adolescent idiopathic scoliosis (AIS). Using DEXA in an unbiased population sample (the Raine Study), we aimed to report the inter-rater reliability and minimal detectable change (MDC₉₅) for scoliosis curve angle measurement, identify likely AIS prevalence, and the concordance between reported AIS diagnosis and DEXA-identified likely AIS. Scoliosis curve angles were measured using the modified Ferguson method on DEXA scans (n = 1238) at age 20 years. For curve angle inter-rater reliability, two examiners measured angles (6-40°) on 41 scans. Likely, AIS was determined with quantitative and qualitative criteria (modified Ferguson angles ≥ 10° and expert review of spinal curves).The inter-rater reliability for scoliosis curve angle measurement was good-excellent (ICC: 0.82; 95% CI: 0.71-0.89; p < 0.001), and MDC₉₅ was 6.2°. The prevalence of likely AIS was 2.1% (26/1238). Diagnosis of AIS was reported despite little or no scoliosis curve (< 3.8°) for 20 participants (1.6%), and diagnosis of AIS was not reported despite scoliosis curve ≥ 10° for 11 participants (0.9%). Results support the use of modified Ferguson method to measure scoliosis curve angles on DEXA. There is potential utility for using a combination of quantitative measurement and qualitative criteria to evaluate DEXA images, to identify likely AIS for reporting prevalence. Without formal school screening, the analysis of DEXA in this population sample suggested that relying on current health professional diagnosis alone could result in 2.5% of this cohort being at risk of false positive diagnosis or delay in necessary management due to non-diagnosis of AIS.

Association between body mass index and posterior spine fusion among patients with adolescent idiopathic scoliosis

INTRODUCTION

Previous studies have found mixed associations between body mass index (BMI) and adolescent idiopathic scoliosis (AIS) incidence and progression. The aim of this study was to examine the association between BMI and the incidence of posterior spine fusion (PSF) among pediatric patients with AIS.

METHODS

This was a retrospective cohort study of patients diagnosed with AIS at a single large tertiary care center between January 1, 2014 and December 31, 2020. BMI-for-age percentiles were used to categorize BMI into four categories: underweight (<5th percentile), healthy weight (≥5th to <85th percentile), overweight (≥85th to <95th percentile), and obese (≥95th percentile). Chi-square and t-tests were used to compare distributions of baseline characteristics by incident PSF outcome status. Multivariable logistic regression assessed the association between BMI category at baseline and incident PSF adjusting for sex, age at diagnosis, race/ethnicity, health insurance type, vitamin D supplementation, and low vitamin D levels.

RESULTS

A total of 2,258 patients met the inclusion criteria with 2,113 patients (93.6%) who did not undergo PSF during the study period and 145 patients (6.4%) who did undergo PSF. At baseline, 7.3% of patients were categorized as underweight, 73.2% were healthy weight, 10.2% were overweight, and 9.3% were obese. Compared to those in the healthy weight group, there was no significant association between PSF and being underweight (adjusted odds ratio [AOR] 1.64, 95% CI 0.90-2.99, p = 0.107), being overweight (AOR 1.25, 95% CI 0.71-2.20, p = 0.436), or being obese (AOR 1.19, 95% CI 0.63-2.27, p = 0.594).

CONCLUSIONS

This study did not find a statistically significant association between underweight, overweight, or obese BMI category and incident PSF among patients with AIS. These findings add to the current mixed evidence on the relationship between BMI and surgical risk and may support the recommendation of conservative treatment to patients regardless of BMI.

Predicting final results of brace treatment of adolescents with idiopathic scoliosis: first out-of-brace radiograph is better than in-brace radiograph-SOSORT 2020 award winner

PURPOSE

In-brace radiograph of adolescents with idiopathic scoliosis (AIS) has been shown to reflect brace efficacy and the possibility of achieving curve correction. Conversely, the first out-of-brace radiograph could demonstrate the patient's ability to maintain the correction. We aimed to determine which of the two radiographs is the best predictor of the Cobb angle at the end of treatment (final radiograph).

DESIGN

Retrospective cohort study of a prospective dataset.

METHODS

The population was selected based on the following inclusion criteria: AIS, age 10-18 years; Risser score 0-2; Cobb angle 25-40°; brace treatment; availability of all radiographs.

STATISTICS

Pearson correlations provide a first exploration of data. The univariate and multivariate logistic regression model tested the predictors. Finally ROC curve provided a check of model accuracy.

RESULTS

A total of 131 patients were included (mean age 13.0 ± 1.3, Cobb angle 33.2 ± 5.5°; 78% females). At the end of treatment, 56% had stabilised, 9% had progressed, and 44% had improved. The difference between the in-brace and final radiographs was 8.0 ± 6.0°, while the difference between the first out-of-brace and final radiographs was 1.8 ± 5.2°. The best predictor of final outcome was the first out-of-brace radiograph (0.80), compared to in-brace (0.68) and baseline (0.59) radiographs. The best cut-offs to predict avoidance of progression were 30% and 10% of the correction rates for the in-brace and first out-of-brace radiographs, respectively.

CONCLUSION

The first out-of-brace radiograph predicts end results better than the in-brace radiograph. It offers an excellent clinical reference for clinicians and patients. The first out-of-brace radiograph should be considered an essential element of future predictive models. LEVEL OF EVIDENCE 1: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Bovine-derived xenograft is a viable bone graft substitute in multilevel, instrumented, spinal fusion

Objective

To evaluate radiological outcomes following the use of xenogeneic bone graft substitute (BGS) in patients undergoing multisegmental spinal fusion.

Summery of Background Data

Data exists for single level and short segment fusions, there presently is a paucity of data on fusion rate after bone augmentation with BGS in multisegmental posterior spinal fusion (PSF). The leading concern is pseudarthrosis, which often leads to a loss of correction after PSF. Therefore, the bone graft is an essential aspect of PSF.

Methods

We retrospectively analysed the radiological data of a consecutive cohort of patients who had been treated for adolescent idiopathic scoliosis (AIS) via multisegmental spinal fusion, in whom a bovine derived BGS had been used and had a complete dataset of 24 months follow-up. The Cobb angle of the main curve was measured pre-operatively and then at 6, 12 and 24 months post-operatively. Loosening of the screws was recorded at the same post-operative time points.

Results

After applying inclusion and exclusion criteria, 28 patients were included. We found no significant change of the cobb angle from the main curve as well as the cobb angle from the thoracic kyphosis during the 24 months of follow up. No patient showed a lack of bony fusion. There was 1 revision surgery, which was due to trauma.

Conclusion

In this cohort, all patients showed successful bone fusion during a 24-month follow-up. Additionally, there was no change in the Cobb angle during the 2-year post-operative period. Our data indicates that the use of bovine-derived BGS supports bone fusion after multisegmental posterior instrumented fusion of the spine.

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

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

A deep convolutional neural network to predict the curve progression of adolescent idiopathic scoliosis: a pilot study

Background

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that predominantly occurs in girls. While skeletal growth and maturation influence the development of AIS, accurate prediction of curve progression remains difficult because the prognosis for deformity differs among individuals. The purpose of this study is to develop a new diagnostic platform using a deep convolutional neural network (DCNN) that can predict the risk of scoliosis progression in patients with AIS.

Methods

Fifty-eight patients with AIS (49 females and 9 males; mean age: 12.5 ± 1.4 years) and a Cobb angle between 10 and 25 degrees (mean angle: 18.7 ± 4.5) were divided into two groups: those whose Cobb angle increased by more than 10 degrees within two years (progression group, 28 patients) and those whose Cobb angle changed by less than 5 degrees (non-progression group, 30 patients). The X-ray images of three regions of interest (ROIs) (lung [ROI1], abdomen [ROI2], and total spine [ROI3]), were used as the source data for learning and prediction. Five spine surgeons also predicted the progression of scoliosis by reading the X-rays in a blinded manner.

Results

The prediction performance of the DCNN for AIS curve progression showed an accuracy of 69% and an area under the receiver-operating characteristic curve of 0.70 using ROI3 images, whereas the diagnostic performance of the spine surgeons showed inferior at 47%. Transfer learning with a pretrained DCNN contributed to improved prediction accuracy.

Conclusion

Our developed method to predict the risk of scoliosis progression in AIS by using a DCNN could be a valuable tool in decision-making for therapeutic interventions for AIS.

Do Pediatric Hospitals Improve Operative Efficiency?

BACKGROUND

In recent years there has been a push towards developing free standing pediatric facilities to provide care specifically towards pediatric patients. The purpose of this study was to determine if moving pediatric cases from a general hospital to a dedicated pediatric facility improved the quality and efficiency of surgical procedures.

METHODS

A retrospective review of pediatric patients undergoing posterior spinal fusion (PSF) was performed. All procedures were performed by one orthopaedic surgeon (SLW) from 2015 to 2019. The procedures were performed at a general hospital (GH) the first two years, and at a pediatric hospital (PH) the subsequent years. Data extracted included patient sex, age, and procedure type as well as procedure duration, operative turnover time, hospital length of stay, transfusion requirements, and operative delay. Exclusively pediatric adolescent idiopathic scoliosis (AIS) patients undergoing PSF were included due to the high volume and consistent surgical procedures therefore limiting confounding variables.

RESULTS

A total of five hundred PSF pediatric procedures were performed during the time period. After excluding non-adolescent idiopathic scoliosis cases, a total of 208 procedures were reviewed (105 at GH; 103 at PH). There was no statistical difference between the groups in regards to operative time (GH: 200 min, PH: 200 min; p=0.91), room turnover time (GH: 38 min, PH: 38 min; p=0.801), or rate of transfusion (GH: 20% PH: 30%; p=0.09). Length of stay was significantly shorter in the PH cohort compared to the GH cohort (4.35 vs. 3.84 days, p=0.0001). However, a smaller proportion of cases at the PH started on time compared to the GH (34% vs. 58%; p=0.0005).

CONCLUSION

Overall, this study demonstrated that AIS procedures at the PH did show a statistically significant reduction in hospital length of stay. However, timely start of the procedure was less likely at this particular facility. Level of Evidence: III.

Association of Ligamentum Flavum Hypertrophy with Adolescent Idiopathic Scoliosis Progression-Comparative Microarray Gene Expression Analysis

The role of the ligamentum flavum (LF) in the pathogenesis of adolescent idiopathic scoliosis (AIS) is not well understood. Using magnetic resonance imaging (MRI), we investigated the degrees of LF hypertrophy in 18 patients without scoliosis and on the convex and concave sides of the apex of the curvature in 22 patients with AIS. Next, gene expression was compared among neutral vertebral LF and LF on the convex and concave sides of the apex of the curvature in patients with AIS. Histological and microarray analyses of the LF were compared among neutral vertebrae (control) and the LF on the apex of the curvatures. The mean area of LF in the without scoliosis, apical concave, and convex with scoliosis groups was 10.5, 13.5, and 20.3 mm2, respectively. There were significant differences among the three groups (p < 0.05). Histological analysis showed that the ratio of fibers (Collagen/Elastic) was significantly increased on the convex side compared to the concave side (p < 0.05). Microarray analysis showed that ERC2 and MAFB showed significantly increased gene expression on the convex side compared with those of the concave side and the neutral vertebral LF cells. These genes were significantly associated with increased expression of collagen by LF cells (p < 0.05). LF hypertrophy was identified in scoliosis patients, and the convex side was significantly more hypertrophic than that of the concave side. ERC2 and MAFB genes were associated with LF hypertrophy in patients with AIS. These phenomena are likely to be associated with the progression of scoliosis.

Curve type, flexibility, correction, and rotation are predictors of curve progression in patients with adolescent idiopathic scoliosis undergoing conservative treatment : a systematic review

AIMS

The aim of this study was to review the current evidence surrounding curve type and morphology on curve progression risk in adolescent idiopathic scoliosis (AIS).

METHODS

A comprehensive search was conducted by two independent reviewers on PubMed, Embase, Medline, and Web of Science to obtain all published information on morphological predictors of AIS progression. Search items included 'adolescent idiopathic scoliosis', 'progression', and 'imaging'. The inclusion and exclusion criteria were carefully defined. Risk of bias of studies was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In all, 6,286 publications were identified with 3,598 being subjected to secondary scrutiny. Ultimately, 26 publications (25 datasets) were included in this review.

RESULTS

For unbraced patients, high and moderate evidence was found for Cobb angle and curve type as predictors, respectively. Initial Cobb angle > 25° and thoracic curves were predictive of curve progression. For braced patients, flexibility < 28% and limited in-brace correction were factors predictive of progression with high and moderate evidence, respectively. Thoracic curves, high apical vertebral rotation, large rib vertebra angle difference, small rib vertebra angle on the convex side, and low pelvic tilt had weak evidence as predictors of curve progression.

CONCLUSION

For curve progression, strong and consistent evidence is found for Cobb angle, curve type, flexibility, and correction rate. Cobb angle > 25° and flexibility < 28% are found to be important thresholds to guide clinical prognostication. Despite the low evidence, apical vertebral rotation, rib morphology, and pelvic tilt may be promising factors. Cite this article: Bone Joint J 2022;104-B(4):424-432.

Supine correction index as a predictor for brace outcome in adolescent idiopathic scoliosis

Aims

The aim of this study was to assess the ability of morphological spinal parameters to predict the outcome of bracing in patients with adolescent idiopathic scoliosis (AIS) and to establish a novel supine correction index (SCI) for guiding bracing treatment.

Methods

Patients with AIS to be treated by bracing were prospectively recruited between December 2016 and 2018, and were followed until brace removal. In all, 207 patients with a mean age at recruitment of 12.8 years (SD 1.2) were enrolled. Cobb angles, supine flexibility, and the rate of in-brace correction were measured and used to predict curve progression at the end of follow-up. The SCI was defined as the ratio between correction rate and flexibility. Receiver operating characteristic (ROC) curve analysis was carried out to assess the optimal thresholds for flexibility, correction rate, and SCI in predicting a higher risk of progression, defined by a change in Cobb angle of ≥ 5° or the need for surgery.

Results

The baseline Cobb angles were similar (p = 0.374) in patients whose curves progressed (32.7° (SD 10.7)) and in those whose curves remained stable (31.4° (SD 6.1)). High supine flexibility (odds ratio (OR) 0.947 (95% CI 0.910 to 0.984); p = 0.006) and correction rate (OR 0.926 (95% CI 0.890 to 0.964); p < 0.001) predicted a lower incidence of progression after adjusting for Cobb angle, Risser sign, curve type, menarche status, distal radius and ulna grading, and brace compliance. ROC curve analysis identified a cut-off of 18.1% for flexibility (sensitivity 0.682, specificity 0.704) and a cut-off of 28.8% for correction rate (sensitivity 0.773, specificity 0.691) in predicting a lower risk of curve progression. A SCI of greater than 1.21 predicted a lower risk of progression (OR 0.4 (95% CI 0.251 to 0.955); sensitivity 0.583, specificity 0.591; p = 0.036).

Conclusion

A higher supine flexibility (18.1%) and correction rate (28.8%), and a SCI of greater than 1.21 predicted a lower risk of progression. These novel parameters can be used as a guide to optimize the outcome of bracing.

Cite this article: Bone Joint J 2022;104-B(4):495–503.

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

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

Accounting for Biomechanical Measures from Musculoskeletal Simulation of Upright Posture Does Not Enhance the Prediction of Curve Progression in Adolescent Idiopathic Scoliosis

A major clinical challenge in adolescent idiopathic scoliosis (AIS) is the difficulty of predicting curve progression at initial presentation. The early detection of progressive curves can offer the opportunity to better target effective non-operative treatments, reducing the need for surgery and the risks of related complications. Predictive models for the detection of scoliosis progression in subjects before growth spurt have been developed. These models accounted for geometrical parameters of the global spine and local descriptors of the scoliotic curve, but neglected contributions from biomechanical measurements such as trunk muscle activation and intervertebral loading, which could provide advantageous information. The present study exploits a musculoskeletal model of the thoracolumbar spine, developed in AnyBody software and adapted and validated for the subject-specific characterization of mild scoliosis. A dataset of 100 AIS subjects with mild scoliosis and in pre-pubertal age at first examination, and recognized as stable (60) or progressive (40) after at least 6-months follow-up period was exploited. Anthropometrical data and geometrical parameters of the spine at first examination, as well as biomechanical parameters from musculoskeletal simulation replicating relaxed upright posture were accounted for as predictors of the scoliosis progression. Predicted height and weight were used for model scaling because not available in the original dataset. Robust procedure for obtaining such parameters from radiographic images was developed by exploiting a comparable dataset with real values. Six predictive modelling approaches based on different algorithms for the binary classification of stable and progressive cases were compared. The best fitting approaches were exploited to evaluate the effect of accounting for the biomechanical parameters on the prediction of scoliosis progression. The performance of two sets of predictors was compared: accounting for anthropometrical and geometrical parameters only; considering in addition the biomechanical ones. Median accuracy of the best fitting algorithms ranged from 0.76 to 0.78. No differences were found in the classification performance by including or neglecting the biomechanical parameters. Median sensitivity was 0.75, and that of specificity ranged from 0.75 to 0.83. In conclusion, accounting for biomechanical measures did not enhance the prediction of curve progression, thus not supporting a potential clinical application at this stage.

Using Ultrasound to Screen for Scoliosis to Reduce Unnecessary Radiographic Radiation: A Prospective Diagnostic Accuracy Study on 442 Schoolchildren

Scoliosis screening is important for timely initiation of brace treatment to mitigate curve progression in skeletally immature children and adolescents. School scoliosis screening programs in Hong Kong follow the protocol of referring children screened positive with a scoliometer and Moiré topography for confirmatory standard radiography. Despite being highly sensitive (88%) in detecting those who require specialist referral, the screening program was found to have a false-positive rate >50%, which could lead to unnecessary X-ray radiation. Radiation-free ultrasound has been reported to be valid and reliable for quantitative assessment of curve severity in scoliosis patients. The aim of this prospective diagnostic accuracy study was to determine the accuracy of ultrasound in determining the threshold of referral that requires X-ray for children screened positive with the scoliometer and Moiré topography. Our study recruited 442 schoolchildren with a mean Cobb angle of 14.0 ± 6.6°. The sensitivity and specificity of ultrasound in predicting the correct referral status, confirmed by X-ray, were 92.3% and 51.6%, with positive and negative predictive values of 29.0% and 96.9%, respectively. Receiver operating characteristic curve analysis revealed area under the curve values of 0.735 for ultrasound alone and 0.832 for ultrasound in combination with measurement of angle of trunk rotation. The finding supports the accuracy of using ultrasound to determine referral status, which could result in a >50% reduction of unnecessary radiation for children undergoing scoliosis screening.

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.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

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

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

Genetic variant of MIR4300HG is associated with progression of adolescent idiopathic scoliosis in a Chinese population

Background

A recent genome-wide association study identified a susceptible locus in MIR4300HG gene that was associated with curve progression of adolescent idiopathic scoliosis (AIS) in the Japanese population. However, the association between the gene and curve progression in other populations remains unclear.

Methods

A cohort of 1952 AIS patients and 2495 healthy controls were included in the case-control analysis. In the case-only analysis, 747 patients were assigned to the progression group and 520 patients were assigned to the non-progression group, respectively. Rs35333564 was genotyped for all the subjects. Paraspinal muscles of 76 patients were collected for the analysis of gene expression. Chi-square test and ANOVA test were used for the intergroup comparison. Pearson correlation analysis was performed to investigate the relationship between the gene expression and curve magnitude.

Results

Variant rs35333564 was significantly associated with the curve severity of AIS (p = 0.025), but not the development of AIS (p = 0.418). Genotype GG was indicated by remarkably lower expression of MIR4300 (p = 0.020) which was significantly correlated with curve magnitude (p = 0.010). As a predicted target gene of MIR4300, the expression of CRTC1 was negatively correlated with MIR4300 expression (p = 0.012, r = −0.287) and positively correlated with curve severity (p = 0.025, r = 0.257).

Conclusions

The association between rs35333564 and curve progression was successfully replicated in a Chinese AIS population. CRTC1 may be the target gene of MIR4300 that plays a role in the curve progression of AIS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02455-w.

Reproducibility and reliability analysis of the Luk Distal Radius and Ulna Classification for European patients with adolescent idiopathic scoliosis

PURPOSE

Current clinical and radiological methods of predicting a patient's growth potential are limited in terms of practicality, accuracy and known to differ in different races. This information influences optimal timing of bracing and surgical intervention in adolescent idiopathic scoliosis (AIS). The Luk classification was developed to mitigate limitations of existing tools. Few reliability studies are available and are limited to certain geographical regions with varying results. This study was performed to analyze reproducibility and reliability of the Luk Distal Radius and Ulna Classification in European patients.

METHODS

This is a radiological study of 50 randomly selected left hand and wrist radiographs of patients with AIS referred to a tertiary referral centre. They were assessed for bone maturity using the Luk Distal Radius and Ulna Classification. Assessment was performed twice by four examiners at an interval of one month. Statistical analysis was performed using the intraclass correlation (ICC) method to determine the reliabilities within and between the examiners.

RESULTS

In total, 50 radiographs (M:F = 13:37) with a mean age of 13.7 years (10 to 18) were assessed for reliability. The inter-rater ICC value was 0.918 for radius assessment and 0.939 for ulna assessment. The intra-rater ICC values for radius assessment ranged between 0.897 and 0.769 and between 0.948 and 0.786 for ulna assessment. There was near perfect correlation for both assessments.

CONCLUSION

This study provides independent evidence that the Luk Distal Radius and Ulna Classification is a reliable tool for assessment of skeletal maturity for European patients. Minimal clinical experience is required to reliably utilize it.

LEVEL OF EVIDENCE

IV.

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.

Sanders stage 7b: Using the appearance of the ulnar physis improves decision-making for brace weaning in patients with adolescent idiopathic scoliosis

Aims

The aim of this study was to investigate whether including the stages of ulnar physeal closure in Sanders stage 7 aids in a more accurate assessment for brace weaning in patients with adolescent idiopathic scoliosis (AIS).

Methods

This was a retrospective analysis of patients who were weaned from their brace and reviewed between June 2016 and December 2018. Patients who weaned from their brace at Risser stage ≥ 4, had static standing height and arm span for at least six months, and were ≥ two years post-menarche were included. Skeletal maturity at weaning was assessed using Sanders staging with stage 7 subclassified into 7a, in which all phalangeal physes are fused and only the distal radial physis is open, with narrowing of the medial physeal plate of the distal ulna, and 7b, in which fusion of > 50% of the medial growth plate of distal ulna exists, as well as the distal radius and ulna (DRU) classification, an established skeletal maturity index which assesses skeletal maturation using finer stages of the distal radial and ulnar physes, from open to complete fusion. The grade of maturity at the time of weaning and any progression of the curve were analyzed using Fisher’s exact test, with Cramer’s V, and Goodman and Kruskal’s tau.

Results

We studied a total of 179 patients with AIS, of whom 149 (83.2%) were female. Their mean age was 14.8 years (SD 1.1) and the mean Cobb angle was 34.6° (SD 7.7°) at the time of weaning. The mean follow-up was 3.4 years (SD 1.8). At six months after weaning, the rates of progression of the curve for patients weaning at Sanders stage 7a and 7b were 11.4% and 0%, respectively for those with curves of < 40°. Similarly, the rates of progression of the curve for those being weaned at ulnar grade 7 and 8 using the DRU classification were 13.5% and 0%, respectively. The use of Sanders stages 6, 7a, 7b, and 8 for the assessment of maturity at the time of weaning were strongly and significantly associated (Cramer’s V 0.326; p = 0.016) with whether the curve progressed at six months after weaning. Weaning at Sanders stage 7 with subclassification allowed 10.6% reduction of error in predicting the progression of the curve.

Conclusion

The use of Sanders stages 7a and 7b allows the accurate assessment of skeletal maturity for guiding brace weaning in patients with AIS. Weaning at Sanders stage 7b, or at ulnar grade 8 with the DRU classification, is more appropriate as the curve did not progress in any patient with a curve of < 40° immediately post-weaning. Thus, reaching full fusion in both distal radial and ulnar physes (as at Sanders stage 8) is not necessary and this allows weaning from a brace to be initiated about nine months earlier. Cite this article: Bone Joint J 2021;103-B(1):141–147.

Intervention versus Observation in Mild Idiopathic Scoliosis in Skeletally Immature Patients

Introduction:

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

Methods:

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

Results:

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

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

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

Conclusion:

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

Effect of core-based exercise in people with scoliosis: A systematic review and meta-analysis

OBJECTIVE

To systematically assess the effectiveness of core-based exercise for correcting a spinal deformity and improving quality of life in people with scoliosis.

DATA SOURCES

The PubMed, Embase, Cochrane Library, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Web of Science databases were searched from inception up to September 30, 2020.

METHODS

Clinical controlled trials were eligible if they compared the effectiveness of core-based exercise to other nonsurgical interventions in people with scoliosis. The revised Cochrane risk of bias assessment tool for randomized trials and the methodological index for non-randomized studies scale were used to assess the risk of bias. The outcomes included the Cobb angle, the angle of trunk rotation and quality of life. RevMan 5.3 was used, and intergroup differences were determined by calculating mean differences (MD) and 95% confidence intervals (CIs).

RESULTS

After screening 1348 studies, nine studies with 325 participants met the inclusion criteria. The exercise group had significantly lower Cobb angles (MD = -2.08, 95% CI: -3.89 to -0.28, P = 0.02) and significantly better quality of life as measured by the Scoliosis Research Society-22 questionnaire (MD = 0.25, 95% CI: 0.02 to 0.49, P = 0.03) than the control groups. However, no significant difference was observed regarding the angle of trunk rotation between groups (MD = -0.69, 95% CI: -2.61 to 1.22, P = 0.48). Furthermore, no serious adverse events were reported. The overall quality of evidence ranged from low to very low.

CONCLUSION

Core-based exercise may have a beneficial role in reducing the Cobb angle and improving quality of life in people with scoliosis in the short term.

PROSPERO REGISTRATION NUMBER

CRD42020160509 (Available at http://www.crd.york.ac.uk/prospero/).

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.

It is not just about the frontal plane: sagittal parameters impact curve progression in AIS patients undergoing brace treatment

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The purpose of this study was to explore the association between pre-brace and in-brace sagittal parameters and curve progression. To date, there has been no published research focused on spinopelvic sagittal parameters and bracing outcomes in AIS. We hypothesize that sagittal spinopelvic parameters are associated with curve progression at 2 years.

METHODS

This study included AIS patients with a pre-brace (PB) major curve between 20° and 45°. The outcome was defined as > 10° curve progression or surgery within 2 years of brace initiation. Spinopelvic parameters included C7-Central Sacral Vertebral Line shift (C7-CSVL), thoracic trunk shift, lumbar lordosis (LL), pelvic incidence (PI), T2-T12 thoracic kyphosis (TK) pelvic incidence-lumbar lordosis (PI-LL) mismatch, sagittal vertical axis (SVA), and pelvic tilt (PT).

RESULTS

Of 50 patients included in this review, [70% Rigo (RCSO) and 30% Boston (BSO)], 16 (32%) patients demonstrated progression (23% of patients with RCSO vs 53% with BSO; p = 0.034). In patients with more than 30% major coronal curve correction (CCC), 23% had progression. 45% of patients progressed when they achieved ≤ 30% correction (p = 0.108). Among PB sagittal parameters and adjusting for coronal curve, patients with an abnormal PB SVA had 3.1 times increased risk of treatment failure compared with patients who had a normal PB SVA. Patients with PB hypo-LL had a 2.8 times increased risk of treatment failure compared with patients who had normal or hyper-LL. Among IB sagittal parameters, patients who had a normal PB PI-LL had a 3.9 times increased risk of treatment failure when they became mismatched in-brace (IB). Patients who had normal pre-brace kyphosis who became hypo-kyphotic IB had an 8.4 times increased risk of treatment failure compared with patients who maintained normal TK or became hyper-kyphotic.

CONCLUSION

These data suggest that we should pay careful attention to sagittal parameters prior to and during brace treatment as braces can control these parameters.

LEVEL OF EVIDENCE

Level III.

Dysregulated Bone Metabolism Is Related to High Expression of miR-151a-3p in Severe Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a common complex disease, and bone homeostasis plays an important role in its pathogenesis. Recent advances in epigenetic research show that dysregulated miRNAs may participate in the development of orthopedic diseases and AIS. The aim of this study was to detect differentially expressed miRNAs in severe AIS and elucidate the mechanism of miRNA deregulation in the pathogenesis of AIS. In the present study, miRNA expression profiles were detected in severe and mild AIS patients as well as healthy controls by miRNA sequencing. Candidate miRNAs were validated in a larger cohort. Primary osteoblasts from severe AIS patients were extracted and isolated to determine the effect of the candidate miRNAs on bone metabolism. Finally, we determined the methylation level in primary osteoblasts from severe AIS patients. The result showed that miR-151a-3p was overexpressed in severe AIS patients. Reduced GREM1 expression was observed in primary osteoblasts from severe AIS patients. miR-151a-3p directly inhibited GREM1 in primary osteoblasts. Relatively lower methylation levels were detected in primary osteoblasts from severe AIS patients. In conclusion, our study revealed that plasma miR-151a-3p levels may serve as a biomarker for severe AIS. Overexpression of miR-151a-3p may interrupt bone homeostasis via inhibiting GREM1 expression. Our result may provide a new biomarker for the early detection of AIS and increase our understanding of the pathogenesis of AIS.

Seasonal Variation in the Volume of Posterior Spinal Arthrodesis Procedures for Pediatric Scoliosis

STUDY DESIGN

Retrospective review of the Healthcare Cost and Utilization Project's Kids' Inpatient Database.

OBJECTIVE

The aim of this study was to investigate variations in surgical case volume in the US for spinal arthrodesis for pediatric patients with scoliosis.

SUMMARY OF BACKGROUND DATA

Approximately 38,000 spinal arthrodesis procedures are performed each year in the United States for pediatric patients with scoliosis. Anecdotally, pediatric spine surgeons report performing more scoliosis procedures during summer months and before national holidays than during other periods, but this has not been reported in the literature. A thorough understanding of seasonal variations in surgical volume may guide the allocation of health care resources.

METHODS

Using the Healthcare Cost and Utilization Project's Kids' Inpatient Database, we identified 32,563 patients aged <21 years with adolescent idiopathic scoliosis (54%), neuromuscular scoliosis (19%), congenital scoliosis (12%), early-onset scoliosis (12%), or scoliosis from other causes (5%) who underwent primary spinal arthrodesis from 2000 through 2016. χ goodness-of-fit tests were used to evaluate seasonal differences in the number of spinal arthrodesis procedures performed. A negative binomial distribution model was used to compare surgical volume by month. Alpha = 0.05.

RESULTS

We found significant seasonal variation in the volume of spinal arthrodesis procedures performed, which persisted after stratifying by type of scoliosis (all, P < 0.001). For all types of scoliosis, surgical volume was highest during the summer. The 3 months with the highest surgical volumes were June, July, and December.

CONCLUSION

The number of spinal arthrodesis procedures performed in the United States for pediatric scoliosis peaked significantly during the summer, with the highest volume of surgeries performed during June, July, and December. An understanding of these variations can help hospitals and providers allocate resources appropriately throughout the year according to predictable changes in surgical volume.

LEVEL OF EVIDENCE

4.

Thoracolumbar Dorsal Ramus Nerve Block Using Continuous Multiorifice Infusion Catheters: A Novel Technique for Postoperative Analgesia After Scoliosis Surgery

Background

This is a brief technical report about a novel regional anesthesia technique in which local anesthetic was deposited around the thoracolumbar dorsal rami nerves via 4 multiorifice pain catheters to obtain analgesia for posterior spinal fusion surgery on scoliosis patients. Scoliosis is the most common deformity of the spine. Currently, most surgeons prefer a dual rod, segmental spinal fixation system that allows multiple anchor points for attachment to the deformed spine. Scoliosis surgery is an extremely painful surgical procedure due to the large incision, surgical trauma to superficial and deep muscles of the back, and the insertion of pedicle screws and metal rods directly into the vertebral column. Postoperative pain management remains very challenging.

Methods

Three patients presented with scoliosis. Intraoperatively, 4 multiorifice catheters were placed lateral to the implanted pedicle screws. Two catheters were placed on each side, and a continuous infusion of 0.2 % ropivacaine was initiated postoperatively to improve the patient's pain control. The catheters remained in place for 48 hours postoperatively and were removed by the surgical team. Gentle traction was applied similar to the way epidural catheters are removed.

Results

All 3 patients reported very low pain scores, low doses of opioid consumption, and satisfaction with their pain control throughout their hospitalization.

Conclusions

Our study results suggest that a thoracolumbar dorsal ramus nerve block using continuous multiorifice infusion catheters significantly improved postoperative comfort and pain and that its implementation into a multimodal analgesic regimen is relatively easy to achieve.

Safety and Effectiveness of Antifibrinolytics in Posterior Scoliosis Surgery for Adolescent Idiopathic Scoliosis: An Analysis of the NSQIP-Pediatric Database

STUDY DESIGN

This was a retrospective study of prospectively collected data.

OBJECTIVE

To utilize a large national database with prospectively collected data [National Surgical Quality Improvement Program Pediatric (NSQIP-Pediatric)] to study the safety and effectiveness of antifibrinolytic use during multilevel posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

There is currently a lack of consensus and evidence regarding the safety and effectiveness of antifibrinolytic use for pediatric patients undergoing corrective surgery for AIS.

MATERIALS AND METHODS

Patients who underwent multilevel PSF for AIS in the 2016 NSQIP-Pediatric database were identified. Preoperative and procedural characteristics were compared between patients who received antifibrinolytics versus those who did not. Multivariate regressions were used to compare perioperative transfusion rates and postoperative outcomes, such as rate of return to the operating room, 30-day readmission, and intensive care unit and hospital length of stay between the 2 treatment groups.

RESULTS

This study included 975 patients who received antifibrinolytics and 223 patients who did not. Patients who received these agents tended to have more levels fused, osteotomies performed, and longer operative times. After controlling for these variances, there were no statistical differences in rate and volume of transfusion, rate of return to the operating room, 30-day readmission, 30-day postoperative complications, or intensive care unit or hospital length of stay between the 2 treatment groups.

CONCLUSIONS

This study did not demonstrate transfusion reduction in the group that received antifibrinolytics. This finding may be, in part, secondary to nonoptimized or nonstandardized protocols for antifibrinolytic use in pediatric deformity surgery or the inability to adequately control for selection bias, as those with greater surgical invasiveness may be more likely to receive antifibrinolytics. Nonetheless, using antifibrinolytics in this population appears safe and not associated with increased perioperative complications.

LEVEL OF EVIDENCE

Level III.

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

BACKGROUND

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

METHOD

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

FINDING

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

INTERPRETATION

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

3D Deformation Patterns of S Shaped Elastic Rods as a Pathogenesis Model for Spinal Deformity in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a three-dimensional (3D) deformity of the spinal column in pediatric population. The primary cause of scoliosis remains unknown. The lack of such understanding has hampered development of effective preventive methods for management of this disease. A long-held assumption in pathogenesis of AIS is that the upright spine in human plays an important role in induction of scoliosis. Here, the variations in the sagittal curve of the scoliotic and non-scoliotic pediatric spines were used to study whether specific sagittal curves, under physiological loadings, are prone to 3D deformation leading to scoliosis. To this end, finite element models of the S shaped elastic rods, which their curves were derived from the radiographs of 129 sagittal spinal curves of adolescents with and without scoliosis, were generated. Using the mechanics of deformation in elastic rods, this study showed that the 3D deformation patterns of the two-dimensional S shaped slender elastic rods mimics the 3D patterns of the spinal deformity in AIS patients with the same S shaped sagittal spinal curve. On the other hand, the rods representing the non-scoliotic sagittal spinal curves, under the same mechanical loading, did not twist thus did not lead to a 3D deformation. This study provided strong evidence that the shape of the sagittal profile in individuals can be a leading cause of the 3D spinal deformity as is observed in the AIS population.

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

STUDY DESIGN

Prognostic study and validation using prospective clinical trial data.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Level 1, prognostic.

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

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

Motivations for weight loss in adolescents with overweight and obesity: a systematic review

BACKGROUND

Adolescents with overweight and obesity report various motivations for weight loss other than the desire for better health. However, there is little evidence regarding the main motivations for weight loss in adolescents. The present systematic review aimed to identify the motivations for weight loss in adolescents with overweight and obesity.

METHODS

A systematic search for original articles published up to December 2016 was carried out in the PubMed, Scopus, LILACS, and ADOLEC databases. The terms used in the search were: motivation, motive, reason, "weight loss," "lose weight," and adolescent.

RESULTS

Six studies (all cross-sectional) met the selection criteria and were included in the review. The instruments used to assess the participants' motivations for weight loss were interviews and questionnaires with open questions. Seventeen motivations for weight loss were identified, the main ones being better health, esthetic/cosmetic reasons, improvements in self-esteem, and avoidance of provocation/bullying.

CONCLUSIONS

The results of the present review show the need for validated instruments to assess the motivations for weight loss in adolescents with overweight and obesity. Moreover, the high frequency of motivations for weight loss related to appearance and social acceptance evidences the need for multidisciplinary weight loss interventions that consider not only the biological factors, but also the psychological and social aspects.

Value of DNA methylation in predicting curve progression in patients with adolescent idiopathic scoliosis

BACKGROUND

There is considerable discordance in the curve progression of adolescent idiopathic scoliosis (AIS) patients between monozygotic (MZ) twins, indicating that nongenetic factors must be involved in the curve progression of AIS patients. Epigenetic processes may constitute one of these factors and have not yet been investigated in relation to curve progression in AIS patients.

METHODS

The genome and methylome of peripheral monocytes were compared between MZ twins discordant for curve progression. Sets of differentially methylated sites were validated using the MassARRAY platform of Sequenome on additional samples.

RESULTS

In the discovery study, we found evidence suggesting a lack of differences at the genome sequence level and the presence of epigenetic differences related to the curve progression of AIS patients. The top 4 differentially methylated CpG sites associated with curve severity were tested, and only site cg01374129 (CpG site located at chr8:122583383, Hg19) was confirmed in two replication cohorts. The methylation levels of site cg01374129 were significantly lower in the progression group than in the nonprogression group. Cox regression analysis demonstrated that hypo-methylation of site cg01374129 was an independent prognostic factor for curve severity. Site cg01374129 methylation as a marker achieved a sensitivity of 76.4% and a specificity of 85.6% in differentiating between samples from patients with and without curve progression (AUC = 0.827; 95% CI: 0.780 to 0.876).

CONCLUSION

Increased curvature is associated with decreased methylation at site cg01374129. Our results indicate that methylation of site cg01374129 may therefore serve as a promising biomarker in differing between patients with and without curve progression.

Asymmetric expression of H19 and ADIPOQ in concave/convex paravertebral muscles is associated with severe adolescent idiopathic scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is the most common paediatric spinal deformity. The etiology and pathology of AIS remain unexplained, and have been reported to involve a combination of genetic and epigenetic factors. Since paravertebral muscle imbalance plays an important role in the onset and progression of scoliosis, we aimed to investigate transcriptomic differences by RNA-seq and identify significantly differentially expressed transcripts in two sides of paravertebral muscle in AIS.

Methods

RNA-seq was performed on 5 pairs of paravertebral muscle from 5 AIS patients. Significantly differentially expressed transcripts were validated by quantitative reverse polymerase chain reaction. Gene expression difference was correlated to clinical characteristics.

Results

We demonstrated that ADIPOQ mRNA and H19 is significantly differentially expressed between two sides of paravertebral muscle, relatively specific in the context of AIS. Relatively low H19 and high ADIPOQ mRNA expression levels in concave-sided muscle are associated with larger spinal curve and earlier age at initiation. We identified miR-675-5p encoded by H19 as a mechanistic regulator of ADIPOQ expression in AIS. We demonstrated that significantly reduced CCCTC-binding factor (CCTF) occupancy in the imprinting control region (ICR) of the H19 gene in the concave-sided muscle contributes to down-regulated H19 expression.

Conclusions

RNA-seq revealed transcriptomic differences between two sides of paravertebral muscle in AIS patients. Our findings imply that transcriptomic differences caused by epigenetic factors in affected individuals may account for the structural and functional imbalance of paravertebral muscle, which can expand our etiologic understanding of this disease.

Electronic supplementary material

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

High Ghrelin Level Predicts the Curve Progression of Adolescent Idiopathic Scoliosis Girls

Background

Adolescent idiopathic scoliosis (AIS) is common deformity with unknown cause. Previous studies have suggested the abnormal serum leptin and ghrelin level in AIS girls. The aim of present study was to evaluate whether the serum leptin and ghrelin level could serve as risk factor in predicting the curve progression in AIS girls. The associations between them and the physical characteristics were also investigated.

Materials and Methods

Circulating leptin and ghrelin levels from 105 AIS girls and 40 age-matched non-AIS girls were examined by enzyme-linked immunosorbent assay. The correlations between ghrelin and leptin levels and growth-related parameters (age, weight, corrected height, corrected BMI, main Cobb angle, and Risser sign) were analyzed in AIS group. Multivariate logistic regression was used to investigate factors predicting curve progression in AIS girls.

Results

A significantly lower leptin level (6.55 ± 2.88 vs. 8.01 ± 3.12 ng/ml, p < 0.05) and a higher ghrelin level (6.33 ± 2.46 vs. 4.46 ± 2.02 ng/ml, p < 0.05) were found in all AIS patients, as compared with normal controls. Curve progression patients had a higher ghrelin level than stable curve patients (7.61 ± 2.48 vs. 5.54 ± 2.11 ng/ml, p < 0.01); for leptin level, there was no significant difference between progression and stable group. The results of multivariate logistic stepwise regression showed that premenarche status, initial main Cobb magnitude that was more than or equal to 23°, high ghrelin level (≥7.30 ng/ml), and lower Risser grade (grades 0 to 2) were identified as risk factors in predicting curve progression. Ghrelin levels of >6.48 ng/ml were predictive for curve progression with 70.00 % sensitivity and 72.31 % specificity, and the area under the curve (AUC) was 0.741 (95 % confidence interval 0.646-0.821).

Conclusions

High ghrelin level may serve as a new quantitative indicator for predicting curve progression in AIS girls.

A scoping review of biopsychosocial risk factors and co-morbidities for common spinal disorders

OBJECTIVE

The purpose of this review was to identify risk factors, prognostic factors, and comorbidities associated with common spinal disorders.

METHODS

A scoping review of the literature of common spinal disorders was performed through September 2016. To identify search terms, we developed 3 terminology groups for case definitions: 1) spinal pain of unknown origin, 2) spinal syndromes, and 3) spinal pathology. We used a comprehensive strategy to search PubMed for meta-analyses and systematic reviews of case-control studies, cohort studies, and randomized controlled trials for risk and prognostic factors and cross-sectional studies describing associations and comorbidities.

RESULTS

Of 3,453 candidate papers, 145 met study criteria and were included in this review. Risk factors were reported for group 1: non-specific low back pain (smoking, overweight/obesity, negative recovery expectations), non-specific neck pain (high job demands, monotonous work); group 2: degenerative spinal disease (workers' compensation claim, degenerative scoliosis), and group 3: spinal tuberculosis (age, imprisonment, previous history of tuberculosis), spinal cord injury (age, accidental injury), vertebral fracture from osteoporosis (type 1 diabetes, certain medications, smoking), and neural tube defects (folic acid deficit, anti-convulsant medications, chlorine, influenza, maternal obesity). A range of comorbidities was identified for spinal disorders.

CONCLUSION

Many associated factors for common spinal disorders identified in this study are modifiable. The most common spinal disorders are co-morbid with general health conditions, but there is a lack of clarity in the literature differentiating which conditions are merely comorbid versus ones that are risk factors. Modifiable risk factors present opportunities for policy, research, and public health prevention efforts on both the individual patient and community levels. Further research into prevention interventions for spinal disorders is needed to address this gap in the literature.

Safe Intraoperative Neurophysiologic Monitoring During Posterior Spinal Fusion in a Patient With Cochlear Implants

OBJECTIVE

Cochlear implants are generally considered a contraindication for any procedure requiring electrical stimulation near the implant. We present a case of a patient undergoing intraoperative transcranial electrical motor-evoked potential monitoring with a cochlear implant without adverse outcomes.

PATIENT

A 12-year-old girl with a history of VACTERL presented with worsening congenital kyphosis and bilateral severe-to-profound hearing loss. Since age 7 the patient used a cochlear implant in the right ear and hearing aid in the left ear. Physical examination and magnetic resonance imaging in 2016 revealed a left-sided 66-degree thoracolumbar kyphosis at T11 making the patient a candidate for surgical correction.

INTERVENTIONS

She underwent a posterior spinal fusion surgery, performed with intraoperative transcranial electrical motor-evoked potential monitoring. Steps were taken to mitigate electrical stimulation of the patient's cochlear implant.

MAIN OUTCOME MEASURES

Postoperative impedance of individual channels, audiometry, and neural response testing were compared with preoperative measurements.

RESULTS

Significant (>10%) impedance changes were observed postoperatively in channels 1, 2, 4, and 6; however, the net variation across all the channels was low (3%). The patient reported no hearing changes, and no significant changes in hearing threshold were seen in postoperative audiometric testing or neural response testing.

CONCLUSION

We present a case of successful posterior spinal fusion with intraoperative neurophysiological monitoring via transcranial electrical stimulation, in a patient with a cochlear implant. With proper precautions, motor-evoked potential monitoring can be safely performed in a patient with a cochlear implant.