Our objective was to assess abnormalities of the odontoid-hip axis (OD-HA) angle in a mild scoliotic population to determine whether screening for malalignment would help predict the distinction between progressive and stable adolescent idiopathic scoliosis (AIS) at early stage. All patients (non-scoliotic and AIS) underwent a biplanar X-ray between 2013 and 2020. In AIS, inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the OD-HA was computed automatically. A reference corridor for OD-HA values in non-scoliotic subjects was calculated as the range [5th–95th percentiles]. A severity index, helping to distinguish stable and progressive AIS, was calculated and weighted according to the OD-HA value. Eighty-three non-scoliotic and 205 AIS were included. The mean coronal and sagittal OD-HA angles in the non-scoliotic group were 0.2° and −2.5°, whereas in AIS values were 0.3° and −0.8°, respectively. For coronal and sagittal OD-HA, 27.5

Our objective was to analysis the barycentremetry, obtained from the external envelope reconstruction of biplanar radiographs, in adolescent idiopathic scoliosis (AIS) and to determine whether assessing would help predict the distinction between progressive and stable AIS at the early stage. A retrospective study with a multicentre cohort of 205 AIS was conducted. All AIS underwent a biplanar X-ray between 2013 and 2020. Inclusion criteria were Cobb angle between 10° and 25°; Risser sign lower than 3; age higher than 10 years; and no previous treatment. A 3D spine reconstruction was performed, and the barycentremetry parameters were computed, i.e., the center of mass position at the apex and the axial torque at the apex, the upper and lower junction. A severity index, helping to distinguish stable and progressive AIS, was computed on the first radiograph, and weighted according to these parameters. A clinical and radiographic monitoring determined if AIS were classified such a stable or progressive scoliosis. One hundred and sixty-two AIS were included (i.e., 87 were classified as stable and 75 as progressive). The apex center of mass position was different between the stable and progressive AIS groups (6 mm, SD = 4 mm for the whole cohort; 5 mm, SD = 4 mm for stable AIS versus 7 mm, SD = 4 mm for progressive AIS; p = 0.02). In AIS thoracic, the specificity and positive predictive value of the severity index increased by 19

ABSTRACT Introduction In chronic low back pain, the use of lumbar orthosis treatment is not part of general recommendations due to a lack of supporting evidence. However, interest in segmental immobilization at the mechanical and postural level is still current in practice, with, however, the belief of negative effects on muscular capacity. The objective of our study was to assess the evolution of muscle capacity after wearing custom-made rigid corset in patients with chronic low back pain. Materials and Methods This is a multicenter study in patients with chronic low back pain, for which the wearing of a rigid postural immobilization corset for 3 months was prescribed. Twenty-two patients completed all follow-up assessments at baseline, 45 days, and 3 months. Evaluations included Biering-Sørensen test, Shirado test, chair test, hand/ground test, lateral inclination test, Quebec scale, and visual analog scale. Results The results revealed a significant improvement of Biering-Sørensen test after 3 months (37.0 ± 53.6 seconds at D0, 41.3 ± 51.7 seconds at D45, and 53.2 ± 60.5 seconds at D90; P < 0.05), in hand/ground distance (21.8 ± 28.5 cm at D0, 15.5 ± 17.8 cm at D45, and 12.2 ± 15.5 cm at D90; P < 0.05), in disability based on the Quebec questionnaire (0.52 ± 0.21 at D0, 0.45 ± 0.19 at D45, and 0.39 ± 0.19 at D90; P < 0.05), and significant reductions in visual analog scale measures of pain (6.0 ± 1.7 at D0, 3.7 ± 1.7 at D45, and 2.7 ± 1.9 at D90; P < 0.05). Conclusions This study shows that the wearing of a rigid orthosis does not alter the muscular endurance capacities of the trunk muscles. In view of the results, wearing a rigid orthosis may be an alternative to treating chronic low back pain. It does not induce muscle loss and may even contribute to motor disinhibition, resulting in improved spinal mobility and functional abilities. Clinical Relevance The common belief that wearing a spinal orthosis leads to muscle loss should no longer be an obstacle to its prescription since it helps to maintain muscle capacity and reduces pain.

La prise en charge de la scoliose idiopathique de l’enfant ou de l’adolescent a évolué au cours de ces dernières années. La meilleure connaissance de l’analyse 3D, l’importance de l’équilibre sagittal ont modifié les habitudes de prescription d’appareillage. La recherche d’un équilibre doit être la priorité et non plus la seule réduction de l’angle de Cobb. Le maintien du mouvement avec l’incitation à une activité sportive sans restriction doit être privilégié. Le podologue doit s’inscrire dans cette démarche ; du dépistage précoce d’une attitude scoliotique ou d’une vraie scoliose, à l’accompagnement d’un enfant dans sa prise en charge rééducative et parfois orthopédique, son intervention peut être précieuse pour aider à rééquilibrer un bassin.

Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine. Spine slenderness, which represents its potential instability to buckling under compressive loads, was shown to be higher in AIS patients than non-scoliotic subjects, but it is not clear at what stage of the progression this difference appeared, nor if slenderness could be used as an early sign of progression. In this study, we hypothesized that slenderness could be an early sign of progression. One-hundred thirty-eight patients and 93 non-scoliotic subjects were included. They underwent standing biplanar radiography and 3D reconstruction of the spine, which allowed computing vertebra and disc slenderness ratio. Then, patients were followed until progression of the deformity or skeletal maturity (stable patients). Vertebral slenderness ratio in AIS patients varied between 2.9 [2.7; 3.0] (T9) and 3.4 [3.2; 3.6] (T1), while disc slenderness ranged from 0.6 [0.6; 0.7] at T6-T7 to 1.2 [1.1; 1.3] at L4-L5. Slenderness ratio increased with age, while disc slenderness tended to decrease with age and Cobb angle. Slenderness was similar between progressive and stable patients, and also between patients and non-scoliotic subjects. In conclusion, spinal slenderness does not appear to be an early sign of progression. Further studies should analyse the development of slenderness during growth, and how it could be affected by non-operative treatment.

Study Design. Multicenter numerical study. Objective. To biomechanically analyze and compare various passive correction features of braces, designed by several centers with diverse practices, for three-dimensional (3D) correction of adolescent idiopathic scoliosis. Summary of Background Data. A wide variety of brace designs exist, but their biomechanical effectiveness is not clearly understood. Many studies have reported brace treatment correction potential with various degrees of control, making the objective comparison of correction mechanisms difficult. A Finite Element Model simulating the immediate in-brace corrective effects has been developed and allows to comprehensively assess the biomechanics of different brace designs. Methods. Expert clinical teams (one orthotist and one orthopedist) from six centers in five countries participated in the study. For six scoliosis cases with different curve types respecting SRS criteria, the teams designed two braces according to their treatment protocol. Finite Element Model simulations were performed to compute immediate in-brace 3D correction and skin-to-brace pressures. All braces were randomized and labeled according to 21 design features derived from Society on Scoliosis Orthopaedic and Rehabilitation Treatment proposed descriptors, including positioning of pressure points, orientation of push vectors, and sagittal design. Simulated in brace 3D corrections were compared for each design feature class using ANOVAs and linear regressions (significance P ≤ 0.05). Results. Seventy-two braces were tested, with significant variety in the design approaches. Pressure points at the apical vertebra level corrected the main thoracic curve better than more caudal locations. Braces with ventral support flattened the lumbar lordosis. Lateral and ventral skin-to-brace pressures were correlated with changes in thoracolumbar/lumbar Cobb and lumbar lordosis (r =− 0.53, r = − 0.54). Upper straps positioned above T10 corrected the main thoracic Cobb better than those placed lower. Conclusions. The corrective features of various scoliosis braces were objectively compared in a systematic approach with minimal biases and variability in test parameters, providing a better biomechanical understanding of individual passive mechanisms’ contribution to 3D correction.

Adolescent idiopathic scoliosis (AIS) is the most common spinal disorder in children. A severity index was recently proposed to identify the stable from the progressive scoliosis at the first standardized biplanar radiographic exam. The aim of this work was to extend the validation of the severity index and to determine if curve location influences its predictive capabilities. AIS patients with Cobb angle between 10° and 25°, Risser 0–2, and no previous treatment were included. They underwent standing biplanar radiography and 3D reconstruction of the spine and pelvis, which allowed to calculate their severity index. Patients were grouped by curve location (thoracic, thoracolumbar, lumbar). Patients were followed up until skeletal maturity (Risser ≥ 3) or brace prescription. Their outcome was compared to the prediction made by the severity index. In total, 205 AIS patients were included; 82% of them (155/189, 95% confidence interval [74–90%]) were correctly classified by the index, while 16 patients were unclassified. Positive predictive ratio was 78% and negative predictive ratio was 86%. Specificity (78%) was not significantly affected by curve location, while patients with thoracic and lumbar curves showed higher sensitivity (≥ 89%) than those with thoracolumbar curves (74%). In this multicentric cohort of 205 patients, the severity index was used to predict the risk of progression from mild to moderate scoliosis, with similar results of typical major curve types. This index represents a novel tool to aid the clinician and the patient in the modulation of the follow-up and, for progressive patients, their decision for brace treatment. • The severity index of adolescent idiopathic scoliosis has the potential to detect patients with progressive scoliosis as early as the first exam. • Out of 205 patients, 82% were correctly classified as either stable or progressive by the severity index. • The location of the main curve had small effect on the predictive capability of the index.

Bracing is the most common treatment to stop the progression of adolescent idiopathic scoliosis. Finite element modeling could help improve brace design, but model validation is still a challenge. In this work, the clinical relevance of a predictive and subject-specific model for bracing was evaluated in forty-six AIS patients. The model reproduces brace action and the patient's spinopelvic adjustments to keep balance. The model simulated 70% or more patients with geometrical parameters within a preselected tolerance level. Although the model simulation of the sagittal plane could be improved, the approach is promising for a realistic and predictive simulation of brace action.

To determine the short-term effect of bracing of adolescent idiopathic scoliotic (AIS) patients on the relationships between spinopelvic parameters related to balance, by comparing their in and out-of-brace geometry and versus healthy subjects. Forty-two AIS patients (Cobb angle 29° ± 12°, ranging from 16° to 61°) with a prescription of orthotic treatment were included retrospectively and prospectively. They all underwent biplanar radiography and 3D reconstruction of the spine and pelvis before bracing as well as less than 9 months after bracing. Eighty-three age-matched healthy adolescents were also included as control group and underwent biplanar radiography and 3D reconstruction. Sacral slope was higher in AIS than healthy patients (p = 0.005). Bracing induced large changes of pelvic tilt (between − 9° and 9°), although patients’ sagittal spinopelvic alignment tended to remain within the normality corridors defined by the healthy patients. Patients had flatter backs compared to healthy subjects and bracing further reduced their spinal curves. The head tended to remain above the pelvis in-brace. Analysis of sagittal alignment from head to pelvis showed that bracing further flattened the patients’ backs and induced large compensating reorientations of the pelvis. Sagittal balance should be included in the planning and evaluation of brace treatment, since it could play a role in its outcome. These slides can be retrieved under Electronic Supplementary Material.

To validate the predictive power and reliability of a novel quasi-automatic method to calculate the severity index of adolescent idiopathic scoliosis (AIS). Fifty-five AIS patients were prospectively included (age 10–15, Cobb 16° ± 4°). Patients underwent low-dose biplanar X-rays, and a novel fast method for 3D reconstruction of the spine was performed. They were followed until skeletal maturity (stable patients) or brace prescription (progressive patients). The severity index was calculated at the first examination, based on 3D parameters of the scoliotic curve, and it was compared with the patient’s final outcome (progressive or stable). Three operators have repeated the 3D reconstruction twice for a subset of 30 patients to assess reproducibility (through Cohen’s kappa and intra-class correlation coefficient). Eighty-five percentage of the patients were correctly classified as stable or progressive by the severity index, with a sensitivity of 92% and specificity of 74%. Substantial intra-operator agreement and good inter-operator agreement were observed, with 80% of the progressive patients correctly detected at the first examination. The novel severity index assessment took less than 4 min of operator time. The fast and semiautomatic method for 3D reconstruction developed in this work allowed for a fast and reliable calculation of the severity index. The method is fast and user friendly. Once extensively validated, this severity index could allow very early initiation of conservative treatment for progressive patients, thus increasing treatment efficacy and therefore reducing the need for corrective surgery. These slides can be retrieved under Electronic Supplementary Material.

STUDY DESIGN:Early detection of progressive adolescent idiopathic scoliosis (AIS) was assessed based on 3D quantification of the deformity.OBJECTIVE:Based on 3D quantitative description of scoliosis curves, the aim is to assess a specific phenotype that could be an early detectable severity index for progressive AIS.SUMMARY OF BACKGROUND DATA:Early detection of progressive scoliosis is important for adapted treatment to limit progression. However, progression risk assessment is mainly based on the follow up, waiting for signs of rapid progression that generally occur during the growth peak.METHODS:Sixty-five mild scoliosis (16 boys, 49 girls, Cobb Angle between 10 and 20°) with a Risser between 0 and 2 were followed from their first examination until a decision was made by the clinician, either considering the spine as stable at the end of growth (26 patients) or planning to brace because of progression (39 patients). Calibrated biplanar x-rays were performed and 3D reconstructions of the spine allowed calculating six local parameters related to main curve deformity. For progressive curve 3D phenotype assessment, data were compared with those previously assessed for 30 severe scoliosis (Cobb Angle > 35°), 17 scoliosis before brace (Cobb Angle > 29°) and 53 spines of nonscoliosis subjects. A predictive discriminant analysis was performed to assess similarity of mild scoliosis curves either to those of scoliosis or nonscoliosis spines, yielding a severity index (S-index). S-index value at first examination was compared with clinical outcome.RESULTS:At the first exam, 53 out of 65 predictions (82%) were in agreement with actual clinical outcome. Approximately, 89% of the curves that were predicted as progressive proved accurate.CONCLUSION:Although still requiring large scale validation, results are promising for early detection of progressive curves.LEVEL OF EVIDENCE:2.

Personalized modeling of brace action has potential in improving brace efficacy in adolescent idiopathic scoliosis (AIS). Model validation and simulation uncertainty are rarely addressed, limiting the clinical implementation of personalized models. We hypothesized that a thorough validation of a personalized finite element model (FEM) of brace action would highlight potential means of improving the model.Forty-two AIS patients were included retrospectively and prospectively. Personalized FEMs of pelvis, spine and ribcage were built from stereoradiographies. Brace action was simulated through soft cylindrical pads acting on the ribcage and through displacements applied to key vertebrae. Simulation root mean squared errors (RMSEs) were calculated by comparison with the actual brace action (quantified through clinical indices, vertebral positions and orientations) observed in in-brace stereoradiographies.Simulation RMSEs of Cobb angle and vertebral apical axial rotation was lower than measurement uncertainty in 79 % of the patients. Pooling all patients and clinical indices, 87 % of the indices had lower RMSEs than the measurement uncertainty.In-depth analysis suggests that personalization of spinal functional units mechanical properties could improve the simulation's accuracy, but the model gave good results, thus justifying further research on its clinical application.

Le risque d'aggravation des scolioses idiopathiques de l'adolescent (SIA) est apprécié sur un faisceau d'arguments cliniques comportant la maturation osseuse, le statut pubertaire, la localisation et l'amplitude de la courbure. Une surveillance attentive au cours de la croissance reste la méthode de référence pour évaluer la progression de la déformation permettant de décider s'il faut ou non traiter. La présente étude décrit un indice de prédiction des SIA progressives, basé sur des critères géométriques tridimensionnels de la déformation obtenus à partir d'acquisitions EOS du rachis entier. Cinquante-six patients avec SIA (Cobb > 10°) non traitée ont été inclus prospectivement dans cette étude. L'âge moyen était de 12 ± 2 ans. L'angle de Cobb moyen était de 15,5°–4,8 (11°–26°) au moment du diagnostic initial. Tous les patients étaient Risser 0, 1 ou 2 lors de leur première visite, et ont été suivis jusqu'à maturation squelettique (Risser > 3) et ou jusqu'à la décision de traiter si l'évolution était cliniquement documentée. Les paramètres décrivant la courbure principale (angle de Cobb, cyphose, rotations axiales vertébrales, torsion) ont été obtenus à partir de radiographies bi-planaires et des reconstitutions en 3D du rachis. Un indice de sévérité (normalisée entre 0 et 1) a été mesuré à partir d'une méthode d'analyse multifactorielle des paramètres tri dimensionnels. Nous avons évalué cet indice en comparant à l'aveugle la prédiction donnée par l'indice de sévérité tel que calculé au premier examen avec le devenir réel du patient. Cinquante- trois des 56 patients (95 %) ont été correctement classés par l'indice de gravité. Un indice de gravité inférieure à 0,4 était associé à une scoliose stable. Un indice supérieur à 0,6 était associé à un risque de progression. Avec 2 faux négatifs et 1 faux positif, la sensibilité était de 97 % et la spécificité de 91 %. Nos résultats préliminaires suggèrent que cet indice de sévérité est un outil pronostique prometteur pour la scoliose chez les patients SIA en période de croissance. Les recommandations pour optimiser la performance de l'indice pronostique sont discutées, en particulier le positionnement du patient dans la cabine EOS, le degré d'incertitude lié à la reconstruction 3D notamment en fonction du type de courbure. Une étude multicentrique à grande échelle est en cours pour valider l'indice de sévérité proposé et étudier sa robustesse pour préparer l'utilisation de l'index en pratique clinique.

The aim of this study was to determine the influence of the severity of the spinal curve on the postural regulation when self-imposed disturbances occur in a seated position in anteroposterior (AP) and mediolateral (ML) orientations. Twelve female adolescents with a right thoracic scoliosis (Cobb = 30.4° ± 9.7) were included in this study. The ground reaction forces (GRF) were studied while the subjects were maintaining their sitting on a seesaw (ML or AP destabilisation). Five conditions were tested: eyes open; with additional loads placed onto the subject's right or left shoulder; or onto the subject's right or left pelvis. We tested the correlation between the Cobb angle and the postural parameters (index of performance and GRF variability) for each condition. When the destabilisation was AP, the Cobb angle was significantly correlated with GRF variability and anterior and concavity index of performance. Two conditions showed higher correlations: stabilisation with the concavity pelvis load (GRF variability) and the open eyes (index of performance). In contrast, whatever the condition tested was, no link was found when the destabilisations were applied in ML direction. The destabilisation in a seated position highlights the influence of the curve severity on the postural organisation. In seated position, the postural control strategies specific to the scoliotic patients were always correlated by severity of curve, especially when the destabilisation is applied in AP directions. This study showed that the unstable seating position can be considered as a pertinent paradigm to help finding a postural clinical index for adolescent idiopathic scoliosis.

The aim was to determine the biomechanical processes involved in postural regulation when self-imposed disturbances occur in the seated position in the antero-posterior direction. Twelve female adolescents with right thoracic scoliosis (SG) (Cobb = 30.4° ± 9.7) and 15 control adolescents (CG) were included in this study. The ground reaction forces (GRF) were studied whilst the subjects maintained their balance in the sitting position on a seesaw. Six conditions were tested: eyes open and closed; with an additional load placed on the subject’s right or left shoulder; and with an additional load on the subject’s right or left pelvis. The SG showed significantly higher force amplitudes and variability and fewer oscillations than the CG in all the conditions. In the SG, the time analysis showed that the duration of the GRF was significantly higher in forward and left directions. Whatever the condition tested, the intra-group differences were not significant. The scoliotic patients in seated position were characterised by larger changes of the GRF, especially with a postural control in the forward and left directions, corresponding to that on the concave side of their spinal curvature. No significant differences were found to exist between the various conditions (load and unload, eyes open and eyes closed). Clinical tests and rehabilitation methods should include assessments of seated patients’ spatio-temporal adaptation to GRF.