The use of the distal radius and ulna classification for the prediction of growth: peak growth spurt and growth cessation

Immediate vs Gradual Brace Weaning Protocols in Adolescent Idiopathic Scoliosis: A Randomized Clinical Trial

Importance

Lack of evidence and consensus for brace weaning protocol in adolescent idiopathic scoliosis (AIS) results in clinicians prescribing gradual weaning in the hope of avoiding curve deterioration after weaning. However, gradual weaning contributes to prolonged brace wear, which can affect spinal stiffness and health-related quality of life (HRQoL).

Objective

To determine whether gradual weaning results in better curve magnitude and truncal balance maintenance after brace weaning vs immediate brace removal for patients with AIS.

Design, Setting, and Participants

This was an open-labeled randomized clinical trial commenced in April 2017 with 24-month follow-up completed in January 2023. Outcome assessors were masked to weaning protocol assigned. The study took place at a territory-wide tertiary scoliosis clinic serving the largest number of referrals in the local population. Patients with AIS ready to wean off of brace wear were eligible (402 were screened; 33 were excluded [15 for <18 hours/day of brace-wear compliance before weaning, 11 were treated with Milwaukee brace, and 7 declined to participate]; and 369 were included), and those who were treated with a custom molded thoracolumbosacral orthosis and had reached skeletal maturity were consecutively recruited.

Interventions

Patients were randomized to gradual weaning protocol (n = 176) with an additional 6 months of nighttime wear before completely stopping or immediate weaning protocol (n = 193) with immediate brace removal at recruitment.

Main Outcomes and Measures

Changes in major curve Cobb angle and truncal balance from the time of weaning to 6-month, 12-month, and 24-month follow-up. HRQoL was also assessed using the refined Scoliosis Research Society 22-item and EuroQol 5-dimension questionnaires.

Results

A total of 369 patients (mean [SD] age, 14.9 [1.1] years; 304 [83.4%] girls) were randomized with 284 (77.0%) completing 24-month longitudinal follow-up. Immediate and gradual weaning groups had no significant differences in change of major Cobb angle at postweaning 6-month (difference, -0.6°; 95% CI, -1.4 to 0.2; P = .17), 12-month (difference, -0.3°; 95% CI, -1.2 to 0.6; P = .47), and 24-month (difference, -0.3°; 95% CI, -1.2 to 0.7; P = .60) follow-up. The number of curve progression, nonprogression, and rebound cases were comparable (χ22 = 2.123; P = .35). Postweaning changes in truncal balance and HRQoL demonstrated no significant differences between groups.

Conclusions

Gradual weaning did not demonstrate superiority to immediate weaning with predefined criteria of Cobb angle and truncal balance maintenance and HRQoL after brace weaning. Gradual and immediate weaning achieved very similar maintenance of brace outcomes in AIS. We therefore recommend the consideration of immediate brace weaning, which aims to benefit patients with earlier time for increased exercises and activity level.

Trial Registration

ClinicalTrials.gov Identifier: NCT03329716.

Subclassification of Sanders Maturation Stage 3 Demonstrates Differences in Spine and Total Height Velocity Between 3A and 3B in Patients With Idiopathic Scoliosis

STUDY DESIGN

A single-center retrospective case-control study.

OBJECTIVE

To compare the spine and total height velocity between Sanders maturation stage (SMS) 3A and 3B.

SUMMARY OF BACKGROUND DATA

Identifying SMS 3 is critical for treating growing children because it represents the early phase of rapid adolescent growth. However, there is limited literature available that clearly describes the growth differences between 3A and 3B.

MATERIALS AND METHODS

The current study included consecutive patients with idiopathic scoliosis staged SMS 3 from January 2012 to December 2021. T1-S1 spine height, total body height, and curve magnitude were measured at the initial and follow-up visits. In addition to the spine and total height velocity calculated per month, corrected height velocity was estimated for curve magnitude using a validated formula. Mann-Whitney U test was used to compare SMS 3A and 3B outcomes, followed by a multiple linear regression model to evaluate the association of the SMS subclassifications to growth velocity adjusted for confounding factors.

RESULTS

A total of 204 patients (66% girls, mean age: 12.3±1.3 y) met the inclusion criteria. Patients staged SMS 3A had higher spine height velocity (mm/month) in both girls (2.3 vs. 1.5, P <0.001) and boys (2.6 vs. 1.7, P <0.001), as well as total height velocity [mm/month; (5.8 vs. 4.3, P <0.001 for girls; 6.6 vs. 4.5, P <0.001 for boys]. Corrected velocity showed similar results with greater spine and total height velocity in SMS 3A. Multivariate analysis indicated a significant association of the SMS subclassification to the spine and total height velocity. The scoliosis curve progression was comparable between SMS 3A and 3B.

CONCLUSIONS

SMS 3A and 3B had differential growth velocity in the spine and total body height. These results indicate the importance of the SMS 3 subclassification for managing scoliosis treatment, including observation, bracing, and surgical interventions with fusion and growth modulation.

LEVEL OF EVIDENCE

Level III-case-control study.

Using the Proximal Femur Maturity Index at Brace Initiation for Adolescent Idiopathic Scoliosis Predicts Curve Progression Risk

BACKGROUND

The Proximal Femur Maturity Index (PFMI) can be used to assess skeletal maturity on existing whole-spine radiographs without additional radiation. However, the relationship between the PFMI at the initiation of bracing for adolescent idiopathic scoliosis (AIS) and subsequent curve progression remains unknown. This study aimed to investigate the relationship between the PFMI and curve progression, and the predictability of risks to adulthood curve progression and surgical thresholds based on the PFMI grade at brace initiation.

METHODS

This was a prospective study of 202 patients with AIS who were prescribed underarm bracing according to the Scoliosis Research Society criteria and had good brace-wear compliance. The patients were followed from brace initiation until complete skeletal maturity. Longitudinal data on the coronal Cobb angle and skeletal maturity assessments using Risser staging, Sanders staging, the distal radius and ulna classification, and the PFMI were collected. Each patient was assessed on whether the major curve progressed to ≥40° (adulthood deterioration) and ≥50° (the surgical threshold). Logistic regressions were used to predict probabilities of curve progression to the 2 thresholds, adjusted for factors that were significant in univariate analyses.

RESULTS

The PFMI correlated with the other skeletal maturity indices (r s [Spearman rank correlation] = 0.60 to 0.72, p < 0.001 for all). The pre-brace PFMI grade correlated with progression to ≥40° (r rb [rank-biserial correlation] = -0.30, p < 0.001) and to ≥50° (r rb = -0.20, p = 0.005). Based on regression models (p < 0.001) adjusted for the pre-brace major Cobb angle and curve type, brace initiation at PFMI grades 2 and 3 for a curve of ≥30° had predicted risks of 30% (95% confidence interval [CI], 4% to 55%) and 12% (95% CI, 7% to 17%), respectively, for progression to the surgical threshold. Brace initiation at PFMI grade 5 had 0% progression risk.

CONCLUSIONS

The PFMI can be used for predicting curve progression and prognosticating brace outcomes in AIS. Patients with brace initiation at PFMI grade 4 for a curve of <30° or at grade 5 were unlikely to progress to the adulthood deterioration or surgical threshold. In comparison, skeletally immature patients initiating bracing at a PFMI grade of ≤3 for a major curve of ≥30° had a higher risk of progression despite compliant brace wear.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Effectiveness of bracing to achieve curve regression in adolescent idiopathic scoliosis

Aims

To systematically evaluate whether bracing can effectively achieve curve regression in patients with adolescent idiopathic scoliosis (AIS), and to identify any predictors of curve regression after bracing.

Methods

Two independent reviewers performed a comprehensive literature search in PubMed, Ovid, Web of Science, Scopus, and Cochrane Library to obtain all published information about the effectiveness of bracing in achieving curve regression in AIS patients. Search terms included "brace treatment" or "bracing," "idiopathic scoliosis," and "curve regression" or "curve reduction." Inclusion criteria were studies recruiting patients with AIS undergoing brace treatment and one of the study outcomes must be curve regression or reduction, defined as > 5° reduction in coronal Cobb angle of a major curve upon bracing completion. Exclusion criteria were studies including non-AIS patients, studies not reporting p-value or confidence interval, animal studies, case reports, case series, and systematic reviews. The GRADE approach to assessing quality of evidence was used to evaluate each publication.

Results

After abstract and full-text screening, 205 out of 216 articles were excluded. The 11 included studies all reported occurrence of curve regression among AIS patients who were braced. Regression rate ranged from 16.7% to 100%. We found evidence that bracing is effective in achieving curve regression among compliant AIS patients eligible for bracing, i.e. curves of 25° to 40°. A similar effect was also found in patients with major curve sizes ranging from 40° to 60° when combined with scoliosis-specific exercises. There was also evidence showing that a low apical vertebral body height ratio, in-brace correction, smaller pre-brace Cobb angle, and daily pattern of brace-wear compliance predict curve regression after bracing.

Conclusion

Bracing provides a corrective effect on scoliotic curves of AIS patients to achieve curve regression, given there is high compliance rate and the incorporation of exercises.

Is there a skeletal age index that can predict accurate curve progression in adolescent idiopathic scoliosis? A systematic review

BACKGROUND

The diagnosis of adolescent idiopathic scoliosis requires clinical and radiographic evaluation; the management options vary depending on the severity of the curve and potential for progression. Identifying predictors of scoliosis progression is crucial to avoid incorrect management; clinical and radiographic factors have been studied as potential predictors. The present study aims to review the literature on radiological indexes for the peak height velocity or curve acceleration phase to help clinicians manage treatment of patients with adolescent idiopathic scoliosis.

METHODS

This systematic review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search was carried out including only peer-reviewed articles written in English that described the radiological indexes assessing skeletal maturity in patients with adolescent idiopathic scoliosis and evaluated their correlation with curve progression, expressed as peak height velocity and/or curve acceleartion phase.

RESULTS

Thirteen studies were included and showed promising results in terms of reliable radiological indexes. Risser staging gives a general measure of skeletal maturity, but it cannot be used as a primary index for driving the treatment of patients with adolescent idiopathic scoliosis since more reliable indexes are available.

CONCLUSION

Skeletal maturity quantification for adolescent idiopathic scoliosis has the potential to significantly modify disease management. However, idiopathic scoliosis is a complex and multifactorial disease: therefore, it is unlikely that a single index will ever be sufficient to predict its evolution. Therefore, as more adolescent idiopathic scoliosis progression-associated indexes are identified, a collective scientific effort should be made to develop a therapeutic strategy based on reliable and reproducible algorithms.

An intelligent composite model incorporating global / regional X-rays and clinical parameters to predict progressive adolescent idiopathic scoliosis curvatures and facilitate population screening

BACKGROUND

Adolescent idiopathic scoliosis (AIS) affects up to 5% of the population. The efficacy of school-aged screening remains controversial since it is uncertain which curvatures will progress following diagnosis and require treatment. Patient demographics, vertebral morphology, skeletal maturity, and bone quality represent individual risk factors for progression but have yet to be integrated towards accurate prognostication. The objective of this work was to develop composite machine learning-based prediction model to accurately predict AIS curves at-risk of progression.

METHODS

1870 AIS patients with remaining growth potential were identified. Curve progression was defined by a Cobb angle increase in the major curve of ≥6° between first visit and skeletal maturity in curves that exceeded 25°. Separate prediction modules were developed for i) clinical data, ii) global/regional spine X-rays, and iii) hand X-rays. The hand X-ray module performed automated image classification and segmentation tasks towards estimation of skeletal maturity and bone mineral density. A late fusion strategy integrated these domains towards the prediction of progressive curves at first clinic visit.

FINDINGS

Composite model performance was assessed on a validation cohort and achieved an accuracy of 83.2% (79.3-83.6%, 95% confidence interval), sensitivity of 80.9% (78.2-81.9%), specificity of 83.6% (78.8-84.1%) and an AUC of 0.84 (0.81-0.85), outperforming single modality prediction models (AUC 0.65-0.78).

INTERPRETATION

The composite prediction model achieved a high degree of accuracy. Upon incorporation into school-aged screening programs, patients at-risk of progression may be prioritized to receive urgent specialist attention, more frequent follow-up, and pre-emptive treatment.

FUNDING

Funding from The Society for the Relief of Disabled Children was awarded to GKHS.

Can the proximal humeral ossification system (PHOS) effectively guide brace weaning in patients with adolescent idiopathic scoliosis?

PURPOSE

The proximal humeral epiphyses can be conveniently viewed in routine spine radiographs. This study aimed to investigate whether the proximal humeral epiphyseal ossification system (PHOS) can be used to determine the timing of brace weaning in adolescent idiopathic scoliosis (AIS), as assessed by the rate of curve progression after brace weaning.

METHODS

A total of 107 patients with AIS who had weaned brace-wear at Risser Stage  ≥  4, no bodily growth and post-menarche  ≥  2 years between 7/2014 and 2/2016 were studied. Increase in major curve Cobb angle > 5° between weaning and 2-year follow-up was considered curve progression. Skeletal maturity was assessed using the PHOS, distal radius and ulna (DRU) classification, Risser and Sanders staging. Curve progression rate per maturity grading at weaning was examined.

RESULTS

After brace-wear weaning, 12.1% of the patients experienced curve progression. Curve progression rate for weaning at PHOS Stage 5 was 0% for curves < 40°, and 20.0% for curves ≥ 40°. No curve progression occurred when weaning at PHOS Stage 5 with radius grade of 10 for curves ≥ 40°. Factors associated with curve progression were: Months post-menarche (p = 0.021), weaning Cobb angle (p = 0.002), curves < 40° versus ≥ 40° (p = 0.009), radius (p = 0.006) and ulna (p = 0.025) grades, and Sanders stages (p = 0.025), but not PHOS stages (p = 0.454).

CONCLUSION

PHOS can be a useful maturity indicator for brace-wear weaning in AIS, with PHOS Stage 5 having no post-weaning curve progression in curves < 40°. For large curves ≥ 40°, PHOS Stage 5 is also effective in indicating the timing of weaning together with radius grade ≥ 10.

Functional and radiologic outcomes of non-displaced scaphoid waist fractures in adolescents approaching skeletal maturity: Comparison between conservative treatment and percutaneous screw fixation

BACKGROUND

Treatment of scaphoid waist fractures is generally conservative in children but surgical in adults, given the relatively high risk of non-union in adults. In adolescents, the required therapeutic strategy is less well defined. The objective of this study was to compare the radiographic and clinical parameters, and the rate of complications, between non-surgical orthopedic treatment (OT) and surgical treatment (ST) by percutaneous screw fixation of these fractures in adolescents approaching skeletal maturity.

HYPOTHESIS

ST of non-displaced scaphoid waist fractures in adolescents allows radiographic union, a functional result and a complication rate comparable to that of ST.

METHODS

This single-center retrospective study included patients who presented with a non-displaced scaphoid waist fracture, with a chronological age (CA) and a bone age (BA) between 14 and 18 years. Clinical and radiographic parameters and complications were analyzed during the trauma and at one year, including functional scores, between two groups of patients; OT and ST.

RESULTS

Thirty-seven patients had OT (63.8%) and 21 had ST (36.2%). The median CA was 16 years [14.25-16]. The median BA was 16 years [15;17] according to the Greulich and Pyle method and corresponded to R9 [R7-R10] and U7 [U7;U8] according to the Distal Radius and Ulnar (DRU) classification system. All non-unions were found in the OT group (23.4% vs. 0%, p=0.019). The duration of immobilization (8 weeks) and the number of consultations were higher after OT than ST. Functional scores were lower in patients with non-union after OT (p≤0.002) CONCLUSION: OT of scaphoid waist fractures in adolescents results in a higher rate of non-union than ST, similar to the rate found in adults. Findings from this study recommend a surgical approach by percutaneous screw fixation.

LEVEL OF EVIDENCE

III; comparative retrospective study.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Utility of a Novel Proximal Femur Maturity Index for Staging Skeletal Growth in Patients with Idiopathic Scoliosis

BACKGROUND

For growing patients, it is ideal to have a growth plate visible in routine radiographs for skeletal maturity assessment without additional radiation. The proximal femoral epiphyseal ossification is in proximity to the spine; however, whether it can be used for assessing a patient's growth status remains unknown.

METHODS

Two hundred and twenty sets of radiographs of the spine and the left hand and wrist of patients with idiopathic scoliosis were assessed for skeletal maturity and reliability testing. Risser staging, Sanders staging (SS), distal radius and ulna (DRU) classification, the proximal humeral ossification system (PHOS), and the novel proximal femur maturity index (PFMI) were used. The PFMI was newly developed on the basis of the radiographic appearances of the femoral head, greater trochanter, and triradiate cartilage. It consists of 7 grades (0 to 6) associated with increasing skeletal maturity. The PFMI was evaluated through its relationship with pubertal growth (i.e., the rate of changes of standing and sitting body height [BH] and arm span [AS]) and with established skeletal maturity indices. Longitudinal growth data and 780 corresponding spine radiographs were assessed to detect peak growth using receiver operating characteristic (ROC) curve analysis.

RESULTS

The PFMI was found to be correlated with chronological age (τ b = 0.522), growth rates based on standing BH (τ b = -0.303), and AS (τ b = -0.266) (p < 0.001 for all). The largest growth rate occurred at PFMI grade 3, with mean standing BH growth rates (and standard deviations) of 0.79 ± 0.44 cm/month for girls and 1.06 ± 0.67 cm/mo for boys. Growth rates of 0.12 ± 0.23 cm/mo (girls) and 0 ± 0 cm/mo (boys) occurred at PFMI grade 6, indicating growth cessation. Strong correlations were found between PFMI gradings and Risser staging (τ b = 0.743 and 0.774 for girls and boys), Sanders staging (τ b = 0.722 and 0.736, respectively), and radius (τ b = 0.792 and 0.820) and ulnar gradings (τ b = 0.777 and 0.821), and moderate correlations were found with PHOS stages (τ b = 0.613 and 0.675) (p < 0.001 for all). PFMI gradings corresponded to as young as SS1, R4, U1, and PHOS stage 1. Fair to excellent interrater and intrarater reliabilities were observed. PFMI grade 3 was most prevalent and predictive for peak growth based on ROC results.

CONCLUSIONS

The PFMI demonstrated clear pubertal growth phases with satisfactory reliability. Grade 3 indicates peak growth and grade 6 indicates growth cessation.

CLINICAL RELEVANCE

The use of PFMI can benefit patients by avoiding additional radiation in skeletal maturity assessment and can impact current clinical protocol of patient visits. PFMI gradings had strong correlations with SS, DRU gradings, and Risser staging, and they cross-referenced to their established grades at peak growth and growth cessation. PFMI may aid in clinical decision making.

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.

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.

Does the Use of Sanders Staging and Distal Radius and Ulna Classification Avoid Mismatches in Growth Assessment with Risser Staging Alone?

BACKGROUND

Although Risser stages are visible on the same radiograph of the spine, Risser staging is criticized for its insensitivity in estimating the remaining growth potential and its weak correlation with curve progression in patients with adolescent idiopathic scoliosis. Risser staging is frequently accompanied by other skeletal maturity indices to increase its precision for assessing pubertal growth. However, it remains unknown whether there is any discrepancy between various maturity parameters and the extent of this discrepancy when these indices are used concurrently to assess pubertal growth landmarks, which are important for the timing of brace initiation and weaning.

QUESTIONS/PURPOSES

(1) What is the chronologic order of skeletal maturity grades based on the growth rate and curve progression rate in patients with adolescent idiopathic scoliosis? (2) What are the discrepancies among the grades of each maturity index for indicating the peak growth and start of the growth plateau, and how do these indices correspond to each other? (3) What is the effectiveness of Risser staging, Sanders staging, and the distal radius and ulna classification in assessing peak growth and the beginning of the growth plateau?

METHODS

Between 2014 and 2017, a total of 13,536 patients diagnosed with adolescent idiopathic scoliosis were treated at our tertiary clinic. Of those, 3864 patients with a radiograph of the left hand and wrist and a posteroanterior radiograph of the spine at the same visits including initial presentation were considered potentially eligible for this study. Minimum follow-up was defined as 6 months from the first visit, and the follow-up duration was defined as 2 years since initial consultation. In all, 48% (1867 of 3864) of patients were eligible, of which 26% (485 of 1867) were excluded because they were prescribed bracing at the first consultation. These patients visited the subsequent clinics wearing the brace, which might have affected body height measurement. Six percent (117 of 1867) of eligible patients were also excluded as their major coronal Cobb angle reached the surgical threshold of 50° and had undergone surgery before skeletal maturity. Another 21% (387 of 1867) of patients were lost before minimum follow-up or had incomplete data, leaving 47% (878) for analysis. These 878 patients with 1139 skeletal maturity assessments were studied; 74% (648 of 878) were girls. Standing body height was measured in a standardized manner by a wall-mounted stadiometer. Several surgeons measured curve magnitude as per routine clinical consultation, skeletal maturity was measured according to the distal radius and ulna classification, and two raters measured Risser and Sanders stages. Reliability tests were performed with satisfaction. Data were collected for the included patients at multiple points when skeletal maturity was assessed, and only up to when brace wear started for those who eventually had bracing. The growth rate and curve progression rate were calculated by the change of body height and major coronal Cobb angle over the number of months elapsed between the initial visit and next follow-up. At each skeletal maturity grading, we examined the growth rate (in centimeters per month) and curve progression rate (in degrees per month) since the skeletal maturity assessment, as well as the mean age at which this maturity grading occurred. Each patient was then individually assessed for whether he or she was experiencing peak growth and the beginning of growth plateau at each timepoint by comparing the calculated growth rate with the previously defined peak growth rate of ≥ 0.7 cm per month and the beginning of growth plateau rate of ≤ 0.15 cm per month in this adolescent idiopathic scoliosis population. Among the timepoints at which the peak growth and the beginning of growth plateau occurred, the median maturity grade of each maturity index was identified as the benchmark grade for comparison between indices. We used the McNemar test to investigate whether pubertal growth landmarks were identified by specific maturity grades concurrently. We assessed the effectiveness of these skeletal maturity indices by the difference in proportions (%) between two benchmark grades in indicating peak growth and the growth plateau.

RESULTS

For girls, the chronological order of maturity grades that indicated peak growth was the radius grade, ulna grade, Sanders stage, and Risser stage. Curve progression peaked between the age of 11.6 and 12.1 years at a similar timing by all maturity indices for girls but was inconsistent for boys. For both sexes, radius (R) grade 6, ulna (U) grade 5, Sanders stage (SS) 3, and Risser stage 0+ were the median grades for peak growth, whereas Risser stage 4, R8/9, U7/8, and SS6/7 indicated the beginning of the growth plateau. The largest discrepancy between maturity indices was represented by Risser stage 0+, which corresponded to six grades of the Sanders staging system (SS2 to SS7) and to R6 in only 41% (62 of 152) of girls in the whole cohort. Despite Risser stage 0+ corresponding to the wide range of Sanders and distal radius and ulna grades, none of the R6, U5, SS3, and Risser stage 0+ was found more effective than another grade in indicating the peak growth in girls. R6 most effectively indicated the peak growth in boys, and Risser stage 0+ was the least effective. For the beginning of the growth plateau in girls, SS6/7 was the most effective indicator, followed by U7/8. Risser stage 4 was the least effective because it indicated 29% (95% CI 21% to 36%; p < 0.001) fewer patients who reached the beginning of the growth plateau than did those with R8/9. Risser stage 4 also indicated 36% (95% CI 28% to 43%; p < 0.001) fewer patients who reached the beginning of the growth plateau than those indicated by U7/8, and it identified 39% fewer patients than SS6/7 (95% CI 32% to 47%; p < 0.001). For boys, similarly, R8/9, U7/8, and SS6/7 were all more effective than Risser stage 4 in identifying when the growth plateau began.

CONCLUSION

Risser stage 0+ corresponds to a wide range of Sanders and distal radius and ulna grades. Risser stage 0+ is least effective in indicating the peak growth in boys, and Risser stage 4 is the least effective maturity grade for indicating when the growth plateau starts in both sexes. The concurrent use of R6 and SS3 can be useful for detecting the peak growth, and SS6/7 in conjunction with U7/8 is most effective in indicating the beginning of the growth plateau. Using a combination of specific grades of Sanders staging and the distal radius and ulna classification can indicate pubertal growth landmarks with reduced risk of underestimating or overestimating skeletal maturity. These findings may aid in refining clinical decision-making of brace initiation and weaning at a more precise timing. Among Risser stage 0, the appearance of R6, U5, and SS3 provide the most effective assessment of peak growth that can indicate the most effective bracing period within which curve progression occurs. For initiation of the growth plateau, Risser 4 is not useful, and SS6/7, R8/9 and U7/8 should be used instead.

LEVEL OF EVIDENCE

Level III, diagnostic study.

An insight of how multiple skeletal maturity indices can be used for growth assessment: relationship between the simplified olecranon, simplified digital, and distal radius and ulna classifications

This cross-sectional study aims to investigate the relationship between the simplified olecranon, simplified digital, and distal radius and ulna (DRU) classifications, and whether they can aid in more comprehensive maturity assessment together. Left hand and wrist and lateral elbow radiographs from pediatric patients were assessed using the three skeletal maturity indices. The association between maturity indices was investigated using Goodman and Kruskal's gamma, and by mapping of individual grades based on chronological age. Specific maturity grades, at which peak height velocity (PHV) occurs as previously identified, were based upon to explore how the three systems interact. A total of 114 patients (63.2% girls) were studied. Correlations and associations between the three maturity parameters were significant (all at P < 0.001). Mapping revealed uneven spans and coverage of different periods by each index. Olecranon stage 1 coincided with R3 (for girls), R4 (for boys), U3, and SS1. Olecranon stage 5 occurred as early as R7, U6, and SS4. Upon elbow fusion, the simplified digital (SS5-SS8) and DRU (R8-R11 and U7-U9) classifications can be used for assessment until maturity. The inter-relationship of the simplified hand, wrist, and olecranon methods indicates their combined use. DRU grades can be used in growth periods which are less well covered. Prepubertal and growth acceleration phase of pubertal growth spurt can best be assessed by both the simplified olecranon (stages 1-3) and DRU classifications (R1-R5 and U1-U4). All three indices are required during PHV. For post-PHV, DRU (R8-R11 and U7-U9) and simplified digital method (SS5-SS8) complement each other for assessment until skeletal maturity.

Clinical presentation, imaging findings, and arthroscopic features in skeletally immature and mature adolescent hip patients: a comparative double-cohort retrospective study

The purpose of this study was to evaluate differences in clinical presentation and extent of surgery required based on skeletal maturity between two cohorts of adolescent hip arthroscopy patients. We hypothesized that skeletal immaturity would be associated with a lower frequency of pincer impingement and a decreased need for surgical acetabuloplasty. A database of 1481 hip arthroscopies performed by a single orthopaedic surgeon between 2008 and 2016 was queried. Patients ≤18 years of age with femoroacetabular impingement were divided into two groups based on Risser score: Risser 1-4 (skeletally immature) or Risser 5 (skeletally mature). Groups were compared with respect to presentation, diagnosis, and arthroscopic procedures performed. Eighty-eight skeletally immature and 49 skeletally mature patients were included. Mixed impingement was more common in skeletally mature patients than immature (67.3% vs. 48.9%, P = 0.037). Skeletal maturity was associated with a significantly increased probability of undergoing acetabuloplasty (odds ratio = 4.6, 95% confidence interval 1.4-15.5; P = 0.014). Extent of chondral degeneration was similar between groups. Our findings support the hypothesis that skeletally immature hips undergo acetabuloplasty less frequently and demonstrate similar chondromalacia compared with a skeletally mature cohort. These results suggest that arthroscopic treatment for impingement-associated hip pain may be a reasonable option to consider for symptomatic skeletally immature patients who have completed a structured course of nonoperative treatment. Additional longitudinal outcomes data are needed to clarify the natural history of impingement-associated hip pain in younger populations and whether hip arthroscopy delays progression of osteoarthritis in these patients.

Controversies with nonoperative management for adolescent idiopathic scoliosis: Study from the APSS Scoliosis Focus Group

PURPOSE

To determine consensus among Asia-Pacific surgeons regarding nonoperative management for adolescent idiopathic scoliosis (AIS).

METHODS

An online REDCap questionnaire was circulated to surgeons in the Asia-Pacific region during the period of July 2019 to September 2019 to inquire about various components of nonoperative treatment for AIS. Aspects under study included access to screening, when MRIs were obtained, quality-of-life assessments used, role of scoliosis-specific exercises, bracing criteria, type of brace used, maturity parameters used, brace wear regimen, follow-up criteria, and how braces were weaned. Comparisons were made between middle-high income and low-income countries, and experience with nonoperative treatment.

RESULTS

A total of 103 responses were collected. About half (52.4%) of the responders had scoliosis screening programs and were particularly situated in middle-high income countries. Up to 34% obtained MRIs for all cases, while most would obtain MRIs for neurological problems. The brace criteria were highly variable and was usually based on menarche status (74.7%), age (59%), and Risser staging (92.8%). Up to 52.4% of surgeons elected to brace patients with large curves before offering surgery. Only 28% of responders utilized CAD-CAM techniques for brace fabrication and most (76.8%) still utilized negative molds. There were no standardized criteria for brace weaning.

CONCLUSION

There are highly variable practices related to nonoperative treatment for AIS and may be related to availability of resources in certain countries. Relative consensus was achieved for when MRI should be obtained and an acceptable brace compliance should be more than 16 hours a day.

Proper positioning of mice for Cobb angle radiographic measurements

Background

There is no recommended standard for positioning of a mouse for radiographic assessment of the spine. This is necessary to have reproducible radiographic data and avoid false positive results. The objective of this study was to investigate the impact of various postures on Cobb angle measurements and to set up a positioning standard for imaging mouse spines.

Methods

This study was conducted in three parts. Firstly, we identified the problem of lack of posture standardization for radiographs. We collected 77 C57BL/6 J mice for spine radiographs and found a scoliosis prevalence of 28.6% with large variations in curve magnitude. Secondly, 24 C57BL/6 J mice underwent 4 consecutive weekly radiographs and observed high variations (relative standard deviation: 125.3%) between radiographs. Thirdly, we collected another 82 C57BL/6 J mice and designed 14 different postures that could take place during imaging. These postures were related to curling of the limbs, and head, pelvic and tail tilting.

Results

The results showed that head and pelvic tilting significantly affects the curve magnitude with effect size (Glass’s delta) over 1.50. Avoiding these incorrect positions during radiographs is warranted. The standard recommended posture for mouse imaging entails positioning the snout, interorbital space, neck and whole spine in one line, and with the limbs placed symmetrical to the trunk, whilst avoiding stretching the body of the mouse.

Conclusions

Our work exemplified the importance of standard protocol during imaging when using an animal model in the scoliosis study. We recommend utilizing this standard in studying various disorders of the spine to avoid technical causes for the appearance of a curve.

Patterns of coronal and sagittal deformities in adolescent idiopathic scoliosis

BACKGROUND

Thoracic scoliosis has been shown to be associated with hypokyphosis in adolescent idiopathic scoliosis (AIS). However, the relationship of sagittal spino-pelvic parameters with different coronal curve patterns and their influence on patient-perceived quality of life is unknown. This study aims to determine the association between coronal and sagittal malalignment in patients with AIS and to determine their effects on SRS-22r scores.

METHODS

A cross-sectional study was conducted on 1054 consecutive patients with AIS. The coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) were measured on standing radiographs. The coronal Cobb angle (mild: 10-20°; moderate: > 20-40°; severe: > 40°) and PI (low: < 35°; average: 35-50°; high: > 50°) were divided into 3 sub-groups for comparison. Relationship between coronal curve magnitudes and sagittal parameters was studied as was their association with SRS-22r scores.

RESULTS

Low PI had smaller SS (30.1 ± 8.3° vs 44.8 ± 7.7°; p < 0.001), PT (- 0.3 ± 8.1° vs 14.4 ± 7.5°; p < 0.001), and LL (42.0 ± 13.2° vs 55.1 ± 10.6°; p < 0.001), negative PI-LL mismatch (- 12.1 ± 13.1° vs 4.1 ± 10.5°; p < 0.001) as compared to large PI. There were no significant relationships with PI and TK (p = 0.905) or curve magnitude (p = 0.431). No differences in sagittal parameters were observed for mild, moderate or severe coronal Cobb angles. SRS-22r scores only correlated with coronal Cobb angle and larger Cobb angles were negatively correlated with the function, appearance and pain domains.

CONCLUSIONS

The sagittal profile for AIS is associated with the pelvic parameters especially PI but not with the coronal curve pattern. All patients have a similar TK regardless of coronal curve type. However, it appears that the coronal deformity is a greater influence on quality of life outcomes especially those > 40°.

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.

Relationship between hand and wrist bone age assessment methods

Assessment of skeletal maturity is crucial for managing growth related problems. Tanner and Whitehouse (TW) hand and wrist bone age assessment is an accurate method; however, it is complex and labor-intensive. Several simplified methods derived from the TW method were proposed, and each had its own character. The purpose of this study is to explore the relationship between these methods for accurate usage.Between 2018 and 2019, a cross-sectional study was performed with consecutive left hand and wrist x-rays obtained from a pediatric orthopedic clinic. Bone age assessments included the distal radius and ulna (DRU) classification, Sanders staging (S), thumb ossification composite index (T), and TW method. Somers delta correlation was conducted to determine the interchangeability of these stages. The mean bone age and standard deviation (SD) of each subgrade were compared and analyzed.Totally 103 films (92 girls) were analyzed with mean age of 12.1 years (range: 8.0-17.9 years). The radius (R) stages had good correlation with S, T, and U stages with a very high Somers delta correlation (P < .05). R5 had relatively large SD (1.5) and referred to T2 and T3; R6 and R7 had the smallest SD (0.3) with reference to T4 or S2; R8 referred to T5 or S3, S4, S5; R9 referred to S6 and S7.The internal relationship between the DRU and digital stages system was well proven. We also provided a simple and accurate way to assess the bone age by combination of some subgrades with smaller SD: 10y-proximal thumb covered without sesamoid (T2); 10.5y-sesamoid just appearing (T3); 11y-distal radial physis just covered (medial double joint line, R6); 11.5y-medial capping of distal radial physis (R7); 12y-bilateral capping of distal radial physis (R8) / phalangeal capping without fusion (S3); 12.5y-distal phalangeal physes start to fuse (S4); 13y-distal phalangeal physes fused (S5); 13.5y-proximal phalangeal physes start to fuse (S6); 14.5y-proximal phalangeal physes fused (S7); 15y-distal radial physis almost fused (R10).Level of Evidence: Diagnostic study, level III.

Effectiveness of scoliosis-specific exercises for alleviating adolescent idiopathic scoliosis: a systematic review

Background

Adolescent idiopathic scoliosis (AIS) is the most common pediatric spinal deformity with reported complications including pain, mental health concern and respiratory dysfunction. The scoliosis-specific exercise (SSE) is prescribed throughout pubertal growth to slow progression although effects are unclear. This review aims to establish the effectiveness of SSE for alleviating AIS in terms of reducing Cobb angle, improving trunk asymmetry and quality of life (QoL). Additionally, it aims to define the effects of age, skeletal maturity, curve magnitude and exercise compliance on the outcomes of SSE.

Methods

A systematic reviewed was conducted to net SSE articles. Searched databases included PubMed, MEDLINE, Cochrane Library, Scopus, CINAHL and Google scholar. The quality of study was critically appraised according to the PEDro scale.

Results

A total of ten trials with an average PEDro score of 6.9/10 were examined in this study. Two randomized controlled trials (RCTs) and two clinical controlled trials suggested that SSE alone and with bracing or traditional exercise had clinical significance in reducing Cobb angle more than 5°. One RCT specifically implicated no comparable effects between bracing and SSE in prevention of curve progression for moderate scoliosis. There was insufficient evidence to support the positive effects of SSE on improving truck asymmetry (n = 4) and QoL (n = 3). Five studies evaluated the interaction effects of age (n = 2), skeletal maturity (n = 1) and curve magnitude (n = 2) with SSE in reducing Cobb angle yet without drawing any firm conclusions.

Conclusions

Insufficient evidence is available to prove that SSE with or without other conservative treatments can reduce Cobb angle, improve trunk balance and QoL. The interaction effects of age, skeletal maturity, curve magnitude, and exercise compliance with SSE in reducing Cobb angle are not proven. Future studies should investigate the relationship of influencing factors and SSE in treating AIS but not only testing its effectiveness.

Trial registration

INPLASY202050100.

Mean 6-Year Follow-up of Magnetically Controlled Growing Rod Patients With Early Onset Scoliosis: A Glimpse of What Happens to Graduates

BACKGROUND

There is no agreement on frequency of distractions of magnetically controlled growing rods (MCGRs) but more frequent and smaller amounts of distractions mimic physiological spine growth. The mid- to long-term follow-up and management at skeletal maturity is unknown.

OBJECTIVE

To analyze patients with mean 6 yr of follow-up and describe the fate of MCGR graduates.

METHODS

Early onset scoliosis (EOS) patients treated with MCGRs with minimum 4 yr of follow-up and/or at graduation were studied. Parameters under study included Cobb angle, spine and instrumented lengths, and rod distraction gains. Relationship between timing of rod exchanges with changes in rate of lengthening was studied.

RESULTS

Ten EOS patients with mean 6.1 yr of follow-up were studied. The greatest Cobb angle correction occurred at the initial implantation surgery and was stable thereafter. Consistent gains in T1-12, T1-S1, and instrumented segment were observed. Rate of lengthening reduced after the first year of use but improved back to initial rates after rod exchange. Seven of the ten patients experienced complications with reoperation rate of 40% for rod distraction failure and proximal foundation problems. Only mild further improvements in all radiological parameters were observed pre- and postfinal surgery. No clinically significant curve progression was observed for rod removal only. All postfinal surgery parameters remained similar at postoperative 2 yr.

CONCLUSION

This study provides an outlook of the end of MCGR treatment. Although this is a fusionless procedure, instrumented segments do experience stiffness limiting further correction and length gain during final surgery whether fusion or rod removal is performed.

Does Curve Regression Occur During Underarm Bracing in Patients with Adolescent Idiopathic Scoliosis?

BACKGROUND

Successful brace treatment entails good control of scoliosis with avoidance of surgery. However, achieving curve regression may be an even better radiological result than prevention of curve progression for patients with adolescent idiopathic scoliosis. Vertebral remodeling may occur with well-fitted braces. Better in-brace curve correction may influence the likelihood of vertebral remodeling and the chance of curve regression. Only a few reports have evaluated curve regression with brace treatment, and the factors associated with these events are unknown.

QUESTIONS/PURPOSES

(1) What changes in curvature are observed with brace treatment for adolescent idiopathic scoliosis? (2) What factors are associated with curve improvement? (3) What factors are associated with curve deterioration? (4) Is curve regression associated with improvements in patient-reported objective outcome scores?

METHODS

Between September 2008 and December 2013, 666 patients with adolescent idiopathic scoliosis underwent underarm brace treatment and were followed until skeletal maturity at 18 years old. Among these patients, 80 were excluded because of early discontinuation of brace treatment (n = 66) and loss to follow-up (n = 14). Hence, 586 patients were included in this study, with a mean brace-wear duration of 3.8 ± 1.5 years and post-weaning follow-up duration of 2.0 ± 1.1 years. The mean age at baseline was 12.6 ± 1.2 years. Most patients were female (87%, 507 of 586) and up to 53% (267 of 507) of females were post-menarche. Bracing outcomes were based on changes in the Cobb angle measured out of brace. These included curve regression, as indicated by at least a 5° reduction in the Cobb angle, curve progression, as indicated by at least a 5° increase in the Cobb angle, and unchanged, as indicated by a change in the Cobb angle of less than 5°. We studied the pre-brace and supine Cobb angles, curve flexibility (pre-brace Cobb angle - supine Cobb angle / pre-brace Cobb angle x 100%), correction rate (pre-brace Cobb angle - in-brace Cobb angle / pre-brace Cobb angle x 100%), location of apical vertebrae, apical ratio (convex vertebral height/concave vertebral height), change in the major curve Cobb angle, and apical ratio post-bracing. The refined 22-item Scoliosis Research Society questionnaire was used for patient-reported outcomes and is composed of five domains (function, pain, appearance, mental health and satisfaction with treatment). Its minimum clinically important difference, based on a scale from 0 to 5, has been quoted as 0.2 for pain, 0.08 for activity and 0.98 for appearance domains. Mental health has no quoted minimum clinically important difference for the adolescent idiopathic scoliosis population. Satisfaction with treatment is described based on improvement or deterioration in domain scores. Intergroup differences between bracing outcomes were evaluated with the Kruskal Wallis test. Univariate analyses of bracing outcomes were performed with a point-biserial correlation coefficient for continuous variables and Pearson's chi-square test for categorical variables. Multivariate logistic regression models were created for improved and deteriorated outcomes. P values < 0.05 were considered significant.

RESULTS

In all, 17% of patients (98 of 586) had an improved angle and 40% of patients (234 of 586) had curve deterioration. In patients who improved, the mean reduction in the Cobb angle was 9 ± 4°, while in patients who deteriorated, the mean increase in the Cobb angle was 15 ± 9°, and this was maintained at the latest post-brace weaning follow-up. Despite a trend for patients with curve regression to have higher baseline flexibility and correction rate, after controlling for age, Risser staging, radius and ulnar grading, and Sanders staging, we found no clinically important differences with increased correction rate or flexibility. We did find that improvement in the Cobb angle after bracing was associated with reduced apical ratio (odds ratio [OR] 0.84 [95% CI 0.80 to 0.87]; p < 0.001). Curve progression was associated with younger age (OR 0.71 [95% CI 0.55 to 0.91]; p = 0.008), pre-menarche status (OR 2.46 [95% CI 1.31 to 4.62]; p = 0.005), and increased apical ratio (OR 1.24 [95% CI 1.19 to 1.30]; p < 0.001) but no clinically important differences were observed with less flexible curves and reduced correction rate. Improvements in scores of the refined 22-item Scoliosis Research Society domains of function (mean difference on a scale from 0 to 5: 0.2; p = 0.001 versus 0.1; p < 0.001) and pain (mean difference on a scale from 0 to 5: 0.2; p = 0.020 versus 0.0; p = 0.853) were greater in the post-brace improvement group than in the deterioration group and fulfilled the minimum clinically important difference threshold. The appearance domain did not fulfill the minimum clinically important difference. Satisfaction with treatment domain score minimally improved with the curve regression group (mean difference on a scale from 0 to 5: 0.2) but deteriorated in the curve progression group (mean difference on a scale from 0 to 5: -0.4).

CONCLUSIONS

Curve regression occurs after underarm bracing and is associated with superior patient-reported outcome scores. This possible change in Cobb angle should be explained to patients before and during bracing. Whether this may help improve patients' duration of brace-wear should be addressed in future studies. Patients with well-fitting braces may experience curve improvement and possible vertebral remodeling. Those braced at a younger age and with increased vertebral wedging are more likely to have curve progression.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Supine flexibility predicts curve progression for patients with adolescent idiopathic scoliosis undergoing underarm bracing

Aims

The aim of this study was to assess whether supine flexibility predicts the likelihood of curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment.

Methods

This was a retrospective analysis of patients with AIS prescribed with an underarm brace between September 2008 to April 2013 and followed up until 18 years of age or required surgery. Patients with structural proximal curves that preclude underarm bracing, those who were lost to follow-up, and those who had poor compliance to bracing (<16 hours a day) were excluded. The major curve Cobb angle, curve type, and location were measured on the pre-brace standing posteroanterior (PA) radiograph, supine whole spine radiograph, initial in-brace standing PA radiograph, and the post-brace weaning standing PA radiograph. Validation of the previous in-brace Cobb angle regression model was performed. The outcome of curve progression post-bracing was tested using a logistic regression model. The supine flexibility cut-off for curve progression was analyzed with receiver operating characteristic curve.

Results

A total of 586 patients with mean age of 12.6 years (SD 1.2) remained for analysis after exclusion. The baseline Cobb angle was similar for thoracic major curves (31.6° (SD 3.8°)) and lumbar major curves (30.3° (SD 3.7°)). Curve progression was more common in the thoracic curves than lumbar curves with mean final Cobb angles of 40.5° (SD 12.5°) and 31.8° (SD 9.8°) respectively. This dataset matched the prediction model for in-brace Cobb angle with less mean absolute error in thoracic curves (0.61) as compared to lumbar curves (1.04). Reduced age and Risser stage, thoracic curves, increased pre-brace Cobb angle, and reduced correction and flexibility rates predicted increased likelihood of curve progression. Flexibility rate of more than 28% has likelihood of preventing curve progression with bracing.

Conclusion

Supine radiographs provide satisfactory prediction for in-brace correction and post-bracing curve magnitude. The flexibility of the curve is a guide to determine the likelihood for brace success. Cite this article: Bone Joint J 2020;102-B(2):254–260.

Reliability Comparison between "Distal Radius and Ulna" and "Simplified Tanner-Whitehouse III" Assessments for Patients with Adolescent Idiopathic Scoliosis

Study Design

This is a retrospective clinical study.

Purpose

In this study, we aim to evaluate the reliability of the distal radius and ulna assessment (DRU) and simplified Tanner-Whitehouse III classification (sTW3) in Japanese patients with adolescent idiopathic scoliosis (AIS).

Overview of Literature

The greatest curvature of a scoliotic spine occurs at peak-height velocity (PHV), which is the time during which an individual’s height increases at the maximum rate. Diagnosing and appropriately treating AIS before PHV is the most effective way in order to prevent unnecessary deterioration of the scoliosis curve. Although it is difficult to detect scoliosis before PHV, DRU and sTW3, which involve evaluations using a left-hand radiograph, have been reported to be effective.

Methods

We retrospectively evaluated 54 hands of 40 girls with AIS who visited Nara Medical University Hospital from 2000 to 2015 using previously collected radiographs. The examiners included a spine surgeon and a pediatric orthopedic surgeon, each with over 10 years of experience. The reliability of the DRU and sTW3 was evaluated using the kappa coefficient.

Results

The left-hand radiographs of 40 female patients with AIS (mean age, 13.9±1.7 years; N=54 hands) were evaluated by two blinded examiners using the sTW3 and DRU methods. The highest inter-observer and intra-observer reliabilities (kappa, 0.64 and 0.62, respectively) for radius evaluation were determined. Radius evaluation by the DRU showed the highest agreement rate and smallest error between the inter- and intra-observer examinations.

Conclusions

The DRU was the most reliable assessment tool, and it has the potential to be useful for precisely determining the stage of skeletal maturity in outpatient clinics.

Cervical vertebral maturation (CVM) stage as a supplementary indicator for the assessment of peak height velocity (PHV) in adolescent idiopathic scoliosis (AIS)

BACKGROUND

Radiographic methods in evaluating the skeletal maturity include Risser sign and Tanner-Whitehouse score. They are either inappropriate or too complex for a busy clinic setting. The cervical vertebral maturation (CVM) stage is commonly used in orthodontics but has been less acknowledged in studies of spinal growth. The purpose of this study was to evaluate whether the CVM stage could be used as an alternative to Risser sign in determining peak height velocity (PHV).

METHODS

This was a two-stage study. Inclusion criteria for stage I study were adolescent female idiopathic scoliosis (AIS) patients, aged between 9-16 years old, who had undergone full spine imaging with clear visibility of the cervical spine. Patients in the stage II study had follow-up through CVM stage 2-4. The correlation between CVM and Risser was analyzed. The spinal growth parameters were measured at each follow-up, and the growth velocity of parameters (PaGVs) was calculated. The PaGVs at CVM stage 2-4 were further compared.

RESULTS

A total of 170 AIS patients were included for stage I study (mean age 12.7 years). The CVM stages were found to correlate strongly with the Risser sign (r=0.85, P<0.01). For those patients with Risser stage 0 with closed TC, 71% were CVM stage 3. Fifty-one patients were included for stage II study. The stature growth velocity averaged 5.4 cm/year in CVM stage 2 patients and 6.3 cm/year in CVM stage 3 patients, which was significantly greater growth than that in CVM stage 4 patients (3.3 cm/year, both P<0.01); similarly, the growth velocity of arm span, trunk height, and spinal lengths were also significantly higher in CVM stage 3 patients compared to CVM stage 2 and 4 patients.

CONCLUSIONS

The CVM stage could provide an alternative option for the assessment of skeletal maturity of subjects with idiopathic scoliosis. CVM stage 3 may be a new sign of PHV.

A Novel Method to Measure the Sagittal Curvature in Spinal Deformities: The Reliability and Feasibility of 3-D Ultrasound Imaging

The objective of this study was to test the reliability of sagittal spinal curvature measurements using 3-D ultrasound in patients with adolescent idiopathic scoliosis (AIS). Ultrasound spinous process angle (USSPA) and ultrasound laminae angle (USLA) were measured on sagittal ultrasound images, while the Cobb angle (XCA) was measured on sagittal X-ray images. Intra-class correlation coefficients (ICC) for the intra- and inter-observer variability, linear regression analysis and Bland-Altman method, including mean absolute difference (MAD), were investigated to evaluate the reliability and validity of the two ultrasound angles compared with XCA. Excellent measurement reliabilities were demonstrated for both ultrasound angles (ICC ≥ 0.91). Moderate to good and significant linear correlations and good agreement were demonstrated between the ultrasound methods and XCA (Thoracic [R² ≥ 0.574] / Lumbar [R² ≥ 0.635]). No significant differences were found for the MADs between both corrected ultrasound angles and XCA. Sagittal ultrasound angles were demonstrated to be reliable for assessing sagittal curvature using spinous processes and laminae and to have good and significant correlations with XCAs. Since it is non-ionizing and relatively low cost, this method opens the possibility of providing frequent curve monitoring and evaluation, and screening for AIS patients, particularly based on sagittal profiles.

When Should We Wean Bracing for Adolescent Idiopathic Scoliosis?

BACKGROUND

Current brace weaning criteria for adolescents with idiopathic scoliosis (AIS) are not well defined. Risser Stage 4, ≥ 2 years since the onset of menarche, and no further increase in body height over 6 months are considered justifications for stopping bracing. However, despite adherence to such standards, curve progression still occurs in some patients, and so better criteria for brace discontinuation are needed.

QUESTIONS/PURPOSES

(1) Is no change in height measurements over 6 months and Risser Stage 4 sufficient for initiating brace weaning? (2) What is the association between larger curves (45°) at brace weaning and the progression risk? (3) Are a more advanced Risser stage, Sanders stage, or distal radius and ulna classification associated with a decreased risk of curve progression? (4) When should we wean patients with AIS off bracing to reduce the time for brace wear while limiting the risk of postweaning curve progression?

METHODS

All AIS patients who were weaned off their braces from June 2014 to March 2016 were prospectively recruited and followed up for at least 2 years after weaning. A total of 144 patients were recruited with mean followup of 36 ± 21 months. No patients were lost to followup. Patients were referred for brace weaning based on the following criteria: they were Risser Stage 4, did not grow in height in the past 6 months of followup, and were at least 2 years postmenarche. Skeletal maturity was assessed with Risser staging, Sanders staging, and the distal radius and ulna classification. Curve progression was determined as any > 5° increase in the Cobb angle between two measurements from any subsequent six monthly followup visits. All radiographic measurements were performed by spine surgeons independently as part of their routine consultations and without knowledge of this study. Statistical analyses included an intergroup comparison of patients with and without curve progression, binomial stepwise logistic regression analysis, odds ratios (ORs) with their 95% confidence intervals (CIs), and a risk-ratio calculation. A reasonable protective maturity stage would generate an OR < 1.

RESULTS

Among patients braced until they had no change in height for 6 months, were 2 years postmenarche for girls, and Risser Stage 4, 29% experienced curve progression after brace weaning. Large curves (≥ 45°) were associated with greater curve progression (OR, 5.0; 95% CI, 1.7-14.8; p = 0.002) as an independent risk factor. Patients weaned at Sanders Stage 7 (OR, 4.7; 95% CI, 2.1-10.7; p < 0.001), radius Grade 9 (OR, 3.9; 95% CI, 1.75-8.51; p = 0.001), and ulna Grade 7 (OR, 3.1; 95% CI, 1.27-7.38; p = 0.013) were more likely to experience curve progression. The earliest maturity indices with a reasonable protective association were Sanders Stage 8 (OR, 0.21; 95% CI, 0.09-0.48; p < 0.001), and radius Grade 10 (OR, 0.42; 95% CI, 0.19-0.97; p = 0.042) with ulna Grade 9 (no patients with curve progression).

CONCLUSION

Brace weaning indications using Risser staging are inadequate. Curve progression is expected in patients with large curves, irrespective of maturity status. Bone age measurement by either Sanders staging or the distal radius and ulna classification provides clearer guidelines for brace weaning, resulting in the least postweaning curve progression. Weaning in patients with Sanders Stage 8 and radius Grade 10/ulna Grade 9 provides the earliest and most protective timepoints for initiating brace weaning.

LEVEL OF EVIDENCE

Level II, prognostic study.

Practice Patterns Among Radiation Oncologists Treating Pediatric Patients With Proton Craniospinal Irradiation

PURPOSE

Craniospinal irradiation (CSI) is an important component of therapy for many pediatric central nervous system malignancies. Proton therapy is increasingly available and used for minimizing radiation exposure to normal tissues. The absence of an exit dose with proton therapy mandates decisions regarding coverage of the vertebral bodies (VB) in non-skeletally mature patients. Although the contents within the thecal sac represent the true clinical target volume (CTV), some physicians target the entire VB in growing children because of concerns over asymmetrical growth. This study aims to assess current practice patterns regarding VB coverage for pediatric patients undergoing CSI.

METHODS AND MATERIALS

Pediatric radiation oncologists were identified from the Particle Therapy Co-Operative Group pediatric subcommittee membership or affiliation with US proton centers. Potential participants were contacted by e-mail with a link to an institutional review board-approved, anonymized web-based survey distributed in June 2017 with follow-up in October 2017. The survey used skip logic and included up to 11 questions regarding practice patterns.

RESULTS

Thirty-three physicians responded to the survey (39%), 5 of which were excluded for lack of recent pediatric proton CSI experience. Of the 28 included responses, 23 physicians sometimes treat the entire VB and 5 physicians report always treating the entire VB. Most common responses regarding anterior CTV expansion for uncertainty were no expansion (n = 9) and 3 to 4 mm (n = 8). Most physicians modify the anterior CTV margin to protect normal structures, most commonly esophagus (n = 15), thyroid (n = 6), heart (n = 5), bowel (n = 4), and pharynx (n = 2).

CONCLUSIONS

Vertebral body coverage in proton CSI varies among radiation oncologists in respect to target delineation, CTV expansions, and modifications for organs at risk. These data suggest the radiation oncology community may benefit from a standardized approach to pediatric proton-based CSI.

A head-to-head comparison of five-level (EQ-5D-5L-Y) and three-level EQ-5D-Y questionnaires in paediatric patients

PURPOSE

The aim of this study was to assess the psychometric properties of a youth version of the EQ-5D five-level questionnaire (5LY) and its three-level version (3LY) in a sample of Chinese paediatric patients.

METHODS

A consecutive sample of idiopathic scoliosis patients were recruited from a referral outpatient scoliosis center at Hong Kong, China in October 2017 and completed the two versions of EQ-5D-Y. Redistribution properties in each dimension of EQ-5D-Y were analyzed between 5LY and 3LY by logistics regressions. Absolute reduction and relative reduction in ceiling effects from the 3LY to the 5LY were calculated. Test-retest reliability was assessed by examining the Gwet's agreement coefficient (Gwet's AC) for five individual dimension responses over the 2-week period.

RESULTS

A total of 129 idiopathic scoliosis patients completed the two versions of EQ-5D-Y at baseline assessment, among which 70 patients completed the test-retest interview in 2-3 weeks after baseline assessment. For redistribution properties, the proportion of inconsistency was low in all the dimensions, ranging from 0.0% ("Usual activities") to 3.9% ("Pain/discomfort"). Ceiling effects were reduced in four dimensions. "Usual activities" dimension showed significant reduction (absolute and relative reductions: 3.9% and 4.3%; p = 0.025) and the "worried/sad/unhappy" dimension showed the largest significant reduction in ceiling effects (absolute and relative reductions: 7.8% and 9.8%; p = 0.012). The 3LY and 5LY showed very good agreement (> 80%) of individual dimension responses between two assessments, except for the "worried/sad/unhappy" dimension in 3LY.

CONCLUSION

Through this head-to-head comparison, the 5LY had significant improvements in ceiling effects in two dimensions when compared to 3LY but other measurement properties of 3LY and 5LY performed similar in the idiopathic scoliosis patient group.

An Insight Into the Health-Related Quality of Life of Adolescent Idiopathic Scoliosis Patients Who Are Braced, Observed, and Previously Braced

STUDY DESIGN

Prospective cross-sectional study.

OBJECTIVE

To determine the health-related quality of life (HRQoL) of adolescent idiopathic scoliosis (AIS) patients undergoing bracing, previously braced and observation only.

SUMMARY OF BACKGROUND DATA

HRQoL is an important treatment outcome measure for AIS. A poor HRQoL may also negatively influence the success of bracing by reducing the likelihood of good brace compliance. Yet, the HRQoL thresholds for patients undergoing observation only, brace treatment or previous brace treatment is not well understood.

METHODS

Chinese AIS patients with refined Scoliosis Research Society 22-item (SRS-22r) Questionnaire and 5-level EQ-5D (EQ-5D-5L) Questionnaire scores were consecutively recruited for this cross-sectional study. Patients were grouped based on their treatment modality (observation only, bracing, previously braced, and postoperatively). Coronal and sagittal Cobb angles, degree of apical vertebral rotation, and curve type were studied. Spearman correlation test, independent t test, and one-way analysis of variance (ANOVA) with Tukey Post-hoc test were performed for statistical analysis.

RESULTS

A total of 652 AIS patients with mean age of 14.8 ± 1.9 years and mean Cobb angle of 18.6° ± 10.0° was studied. The respective mean SRS-22r total scores for bracing, observation, and previously braced groups were 4.20, 4.54, and 4.42, and mean EQ-5D-5L scores were 0.87, 0.95, and 0.92. The total and domain scores were correlated with coronal Cobb angles (P < 0.001) while only EQ-5D-5L correlated with sagittal Cobb angles (P < 0.001). Curves greater than 40° had worse HRQoL (P < 0.001). Currently braced patients had significantly worse HRQoL than those under observation, as indicated by lower EQ-5D-5L (0.08) and SRS-22r (0.35) scores (P < 0.001 to P < 0.05). Previously braced patients had better HRQoL than currently braced patients, with 0.05 higher EQ-5D-5L score (P < 0.001), and 0.23 higher SRS-22r score (P < 0.001). However, currently braced patients were more satisfied with treatment (1.94 difference; P < 0.001) than previously braced. There were no gross differences between patients previously braced and undergoing observation only.

CONCLUSION

The negative impact of bracing on HRQoL is only transient as previously braced patients have superior HRQoL. It appears as though the EQ-5D-5L scores are more sensitive to changes in the sagittal profile as compared with SRS-22r. Our study highlights the differences in HRQoL between patients only being observed, undergoing bracing or previous brace treatment and the importance of monitoring HRQoL throughout follow-up. Further longitudinal studies may help determine the timing and threshold of HRQoL changes during the entire duration of bracing as well as after brace weaning.

LEVEL OF EVIDENCE

2.

Predicted final spinal height in patients with adolescent idiopathic scoliosis can be achieved by surgery regardless of maturity status

AIMS

The aim of this study was to investigate the impact of maturity status at the time of surgery on final spinal height in patients with an adolescent idiopathic scoliosis (AIS) using the spine-pelvic index (SPI). The SPI is a self-control ratio that is independent of age and maturity status.

PATIENTS AND METHODS

The study recruited 152 female patients with a Lenke 1 AIS. The additional inclusion criteria were a thoracic Cobb angle between 45° and 70°, Risser 0 to 1 or 3 to 4 at the time of surgery, and follow-up until 18 years of age or Risser stage 5. The patients were stratified into four groups: Risser 0 to 1 and selective fusion surgery (Group 1), Risser 0 to 1 and non-selective fusion (Group 2), Risser 3 to 4 and selective fusion surgery (Group 3), and Risser 3 to 4 and non-selective fusion (Group 4). The height of spine at follow-up (HOS_f) and height of pelvis at follow-up (HOP_f) were measured and the predicted HOS (pHOS) was calculated as 2.22 (SPI) × HOP_f. One-way analysis of variance (ANOVA) was performed for statistical analysis.

RESULTS

Of the 152 patients, there were 32 patients in Group 1, 27 patients in Group 2, 48 patients in Group 3, and 45 patients in Group 4. Significantly greater HOS_f was observed in Group 3 compared with Group 1 (p = 0.03) and in Group 4 compared with Group 2 (p = 0.02), with similar HOP_f (p = 0.75 and p = 0.83, respectively), suggesting that patients who undergo surgery at Risser grade of 0 to 1 have a shorter spinal height at follow-up than those who have surgery at Risser 4 to 5. HOS_f was similar to pHOS in both Group 1 and Group 2 (p = 0.62 and p = 0.45, respectively), indicating that undergoing surgery at Risser 0 to 1 does not necessarily affect final spinal height.

CONCLUSION

This study shows that fusion surgery at Risser 0 may result in growth restriction unlike fusion surgery at Risser 3 to 4. Despite such growth restriction, AIS patients could reach their predicted or 'normal' spinal height after surgery regardless of baseline maturity status due to the longer baseline spinal length in AIS patients and the remaining growth potential at the non-fusion levels. Cite this article: Bone Joint J 2018;100-B:1372-6.

APSS-ASJ Best Clinical Research Award: Predictability of Curve Progression in Adolescent Idiopathic Scoliosis Using the Distal Radius and Ulna Classification

Study Design

Prospective study.

Purpose

To determine the risk of clinically significant curve progression in adolescent idiopathic scoliosis (AIS) based on the initial Cobb angle and to test the utility of the distal radius and ulna (DRU) classification in predicting these outcomes.

Overview of Literature

Determining the remaining growth potential in AIS patients is necessary for predicting prognosis and initiating treatment. Limiting the maturity Cobb angle to <40° and <50° reduces the risk of adulthood progression and need for surgery, respectively. The risk of curve progression is the greatest with skeletally immature patients and thus warrants close monitoring or early intervention. Many parameters exist for measuring the skeletal maturity status in AIS patients, but the DRU classification has been shown to be superior in predicting peak growth and growth cessation. However, its predictive capabilities for curve progression are unknown.

Methods

Totally, 513 AIS patients who presented with Risser 0–3 were followed until either skeletal maturity or the need for surgery, with a minimum 2-year follow-up period. Outcomes of 40° and 50° were used for probability analysis based on the cut-offs of adulthood progression risk and surgical threshold, respectively.

Results

At the R6/U5 grade, most curves (probability of ≥48.1%–55.5%) beyond a Cobb angle of 25° progressed to the 40° threshold. For curves of ≥35°, there was a high risk of unfavorable outcomes, regardless of skeletal maturity. Most patients with the R9 grade did not progress, regardless of the initial curve magnitude (probability of 0% to reach the 50° threshold for an initial Cobb angle of ≥35°).

Conclusions

This large-scale study illustrates the utility of the DRU classification for predicting curve progression and how it may effectively guide the timing of surgery. Bracing may be indicated for skeletally immature patients at an initial Cobb angle of 25°, and those with a scoliosis ≥35° are at an increased risk of an unfavorable outcome, despite being near skeletal maturity.

Rod Lengthening With the Magnetically Controlled Growing Rod: Factors Influencing Rod Slippage and Reduced Gains During Distractions

STUDY DESIGN

Prospective study.

OBJECTIVE

To identify the factors that are associated with rod slippage and to study the pattern of achieved length gain with a standard distraction methodology.

SUMMARY OF BACKGROUND DATA

Ability to achieve successful magnetically controlled growing rod (MCGR) distraction is crucial for gradual spine lengthening. Rod slippage has been described as a failure of internal magnet rotation leading to a slippage and an inability to distract the rod. However, its onset, significance, and risk factors are currently unknown. In addition, how this phenomenon pertains to actual distracted lengths is also unknown.

METHODS

A total of 22 patients with MCGR and at least six distraction episodes were prospectively studied. Patients with rod slippage occurring less than six distraction episodes were considered early rod slippage whereas those with more than six episodes or have yet to slip were grouped as late rod slippage. The association of parameters including body habitus, maturity status, age of implantation, total number of distractions, months of distraction from initial implantation, initial and postoperative Cobb angle, T1-T12, T1-S1, T5-T12 kyphosis, curve flexibility, instrumented length, and distance between magnets in dual rods and between the magnets and apex of the curve with early or late onset of rod slippage were studied. Differences between expected and achieved distraction lengths were assessed with reference to rod slippage episodes and rod exchanges to determine any patterns of diminishing returns.

RESULTS

Patients had mean age of 7.1 years at diagnosis with mean follow-up of 49.8 months. A mean 32.4 distractions were performed per patient. Early rod slippage occurred in 14 patients and late rod slippage occurred in eight patients. Increased height, weight, body mass index, older age, increased T1-12 and T1-S1 lengths, and less distance between magnets were significantly associated with early rod slippage. Expected distraction lengths did not translate to achieve distraction lengths and reduced gains were only observed after achieving one-third of the allowable distracted length in the MCGR. Length gains return to baseline after rod exchange.

CONCLUSION

This is the first study to specifically analyze the impact of rod slippage on distraction lengths and the risk factors associated with its onset and frequency. Increased body habitus and reduced distance between internal magnets significantly influenced rod slippage events. Diminishing returns in distracted length gains were only observed after a period of usage.

LEVEL OF EVIDENCE

3.

Curve Progression in Adolescent Idiopathic Scoliosis Does Not Match Skeletal Growth

BACKGROUND

Determining the peak growth velocity of a patient with adolescent idiopathic scoliosis (AIS) is important for timely treatment to prevent curve progression. It is important to be able to predict when the curve-progression risk is greatest to maximize the benefits of any intervention for AIS. The distal radius and ulna (DRU) classification has been shown to accurately predict skeletal growth. However, its utility in predicting curve progression and the rate of progression in AIS is unknown.

QUESTIONS/PURPOSES

(1) What is the relationship between radius and ulna grades to growth rate (body height and arm span) and curve progression rate? (2) When does peak curve progression occur in relation to peak growth rate as measured by months and by DRU grades? (3) How many months and how many DRU grades elapse between peak curve progression and plateau?

METHODS

This was a retrospective analysis of a longitudinally maintained dataset of growth and Cobb angle data of patients with AIS who presented with Risser Stages 0 to 3 and were followed to maturity at Risser Stage 5 at a single institute with territory-wide school screening service. From June 2014 to March 2016, a total of 513 patients with AIS fulfilled study inclusion criteria. Of these, 195 were treated with bracing at the initial presentation and were excluded. A total of 318 patients with AIS (74% girls) with a mean age of 12 ± 1.5 years were studied. For analysis, only data from initial presentation to commencement of intervention were recorded. Data for patients during the period of bracing or after surgery were not used for analysis to eliminate potential interventional confounders. Of these 318 patients, 192 were observed, 119 were braced, and seven underwent surgery. Therefore 192 patients (60.4%) who were observed were followed up until skeletal maturity at Risser Stage 5; no patients were lost to followup. The mean curve magnitude at baseline was 21.6 ± 4.8. Mean followup before commencing intervention or skeletal maturity was 4.3 ± 2.3 years. Standing body height, arm span, curve magnitude, Risser stage, and DRU classification were studied. A subgroup analysis of 83 patients inclusive of acceleration, peak, and deceleration progression phases for growth and curve progression was studied to determine any time lag between growth and curve progression. Results were described in mean ± SD.

RESULTS

There was positive correlation between growth rate and curve progression rate for body height (r = 0.26; p < 0.001) and arm span (r = 0.26; p < 0.001). Peak growth for body height occurred at radius grade (R) 6 (0.56 ± 0.29 cm/month) and ulna grade (U) 4 (0.65 ± 0.31 cm/month); peak change in arm span occurred at R5 (0.67 ± 0.33 cm/month) and U3 (0.67 ± 0.22 cm/month); and peak curve progression matched with R7 (0.80 ± 0.89 cm/month) and U5 (0.84 ± 0.78 cm/month). Subgroup analysis confirmed that peak curve progression lagged behind peak growth rate by approximately 7 months or one DRU grade. The mean time elapsed between the peak curve progression rate and the plateau phase at R9 U7 was approximately 16 months, corresponding to two DRU grades.

CONCLUSIONS

By using a standard skeletal maturity parameter in the DRU classification, this study showed that the maximal curve progression occurs after the peak growth spurt, suggesting that the curve should be monitored closely even after peak growth. In addition, the period of potential curve continuing progression extends nearly 1.5 years beyond the peak growth phase until skeletal maturity. Future studies may evaluate whether by observing the trend of growth and curve progression rates, we can improve the outcomes of interventions like bracing for AIS.

LEVEL OF EVIDENCE

Level II, prognostic study.

Managing the Pediatric Spine: Growth Assessment

Management of pediatric spinal deformities requires an accurate prediction of growth spurts to allow for timely initiation of treatment and prevention of curve progression. Determining remaining growth potential is also important for avoiding prolonged unnecessary treatment, e.g. bracing for patients nearing skeletal maturity. Many clinical and radiological growth parameters have been developed to aid clinicians in growth prediction. Of these, several commonly used measures such as height and arm span growth trends, timing of menarche, and the Risser sign are mostly retrospective and lack strong predictive utility. Bone age assessments, such as digital skeletal age and the distal radius and ulna classification, are more accurate parameters, but further research is required to determine interethnic variations and develop their role in management decisions.