Natural history of AIS >30° in skeletally mature patients is poorly defined. Studies reporting rates and risk factors for progression are predominantly of large curves in immature patients. Our aim was to determine the rate of curve progression in AIS following skeletal maturity, any associated changes in SRS-22 scores, and identify any potential predictors of curve progression. Patients enrolled in a prospective, longitudinal, multicentre non-surgical AIS database were evaluated. All patients had minimum 2 year follow-up, idiopathic scoliosis >30°, and were skeletally mature. SRS-22 functional outcome scores and radiographic data were compared at baseline and 2-year follow-up. Patients were divided into 3 groups based on curve size: A=30°-39°, B=40°-49°, C= >50°. Curve progression was defined as any change in curve magnitude. There were 80 patients, majority females (93.8%) with a mean age of 16.5+/−0.16. Mean BMI was 21+/−0.31 with 15.1% overweight. Mean major cobb at baseline was 38.3°+/−0.88°. At 2 year follow-up 46.3% of curves had progressed an average 3.4°+/−0.38°. Of curves that progressed, patients in group A had the largest mean rate of progression followed by group B. SRS-22 scores on average declined significantly over 2 years in this cohort (4.23 to 4.08; p=0.002). Patients who progressed had on average a more significant decline in SRS outcome scores compared to those that did not (p=0.018, p=0.041 respectively), with the most significant change noted in the Self-Image domain (p=0.03). There was no significant difference in the change in SRS scores over 2 years based on curve size. Univariate analysis did not identify any factors predictive of curve progression in this cohort. Skeletally mature patients with AIS >30°may continue to have a risk of progression at a mean rate of 1.7°/yr and significant decline in SRS-22 outcome scores, in particular Pain and Self-Image, over time

Introduction. Idiopathic scoliosis is a lateral curvature of the spine >10° as measured on a frontal plane radiograph by the Cobb angle. Important variables in assessing the risk of curve progression include a young age at presentation, female sex, a large amount of growth remaining, the rate of growth, the curve magnitude, and the curve location. Curves >20° have an inherently low risk of progression. Surgery is indicated for curves >50° or rapidly progressing curves. The timing of surgery is paramount in order to intervene in cases where rapid progression is evident to prevent further deterioration. There is a greater likelihood for more complex surgery to be required in major curves. At present, there are severe restrictions on resources to cater for patients with scoliosis. As a result, patients spend excessive periods on waiting lists prior to having their procedure. The aim of this study is to analyse the progression of curves of patients while on the waiting list and assess the cost implications of curve deterioration. Methods. A retrospective analysis of 40 cases of adolescent idiopathic scoliosis performed from between 2007-2010 was carried out. All radiographs at the time of being placed on the waiting list and the time of admission were reviewed to assess the Cobb angle. The radiographs were analysed independently by three spinal surgeons to determine what level of surgical intervention they would recommend at each time point. The final procedure performed was also recorded. A cost analysis was carried out of all of the expenses that are incurred as part of scoliosis surgery, including length of hospital stay, intensive care admission, spinal monitoring, implant cost, and the requirement for multiple procedures. Results. The average time on the waiting list was 12 months (range 6 – 16 months). Comparison of radiographs at the time of listing and time of admission revealed a deterioration of the Cobb angle by an average of 12°. The average Cobb angle at time of surgery was 78° (range 55° - 96°). Analysis of cost implications revealed an increase in cost based on implant requirements, length of stay and intensive care admission estimated at 25%. Conclusion. The results of this study demonstrate that there is a significant deterioration of scoliosis curvature in patients while on the waiting list. The consequence of this progression results in longer operative time, increased requirement for intensive care beds, an increase in requirements for additional levels of pedicle instrument, and a prolonged length of stay. The implications of the deterioration in curvature result in an increase in overall cost estimated at 25%. Waiting list initiatives established over the past 6 months have reduced the waiting list to 6-9 months. Further efforts to continue this initiative are likely to give rise to further cost reductions and result in more manageable curvatures being dealt with in a timely fashion

There is a significant positive association between hours of brace wear and rate of success in the treatment of Adolescent Idiopathic Scoliosis (AIS). The abandon rate reported in the literature averages 18%. In a recent randomized trial conducted at our center; the abandon rate was 4%. We aim to document the abandon rate towards brace treatment during the COVID-19 pandemic and its impact on AIS progression. We reviewed a database of AIS patients recruited between March and September 2020. Inclusion criteria were patients with AIS under brace treatment according to SRS criteria. The patients were divided in 2 cohorts: those with a self-reported good adherence to treatment and those who voluntarily abandoned treatment during follow-up. Patients with irregular adherence were excluded. Data analysis included age, gender, Risser stage, type of brace, Cobb angles at first visit and last follow-up (mean 11 months) and % of progression. Unpaired student tests were used for comparison. 154 patients met inclusion criteria. 20 patients were excluded due to irregular adherence. 89 patients (age: 12.1 y.o. ±1.4) reported good adherence to treatment, while 45 patients (age: 12.6 y.o. ±1.5) abandoned treatment, an abandon rate of 29%. The cohort of compliant patients started treatment with a mean main thoracic (MT) curve of 26° and finished with 27°. The mean difference between measurements was +0.65°±7.5; mean progression rate was −4.6%. However, patients who abandoned treatment started with a mean MT curve of 28° and finished with 33°, with a mean increase of +5°±8 and a mean progression rate of −11%. The differences between the 2 cohorts were statistically significant (p=0.002). Five (5) patients from the abandon group were offered for surgery because of curve progression. The abandon rate of brace treatment in AIS significantly increased during the first wave of COVID-19 pandemic. Patients who voluntarily discontinued treatment had significant increases in curve progression and surgical indication rates

Prior to the introduction of steroid management in Duchenne Muscular Dystrophy (DMD), the prevalence of scoliosis approached 100%, concomitant with progressive decreases in pulmonary function. As such, early scoliosis correction (at 20-25°) was advocated, prior to substantial pulmonary function decline. With improved pulmonary function and delayed curve progression with steroid treatment, the role of early surgery has been questioned. The purpose of this study was to compare the post-operative outcomes of early versus late scoliosis correction in DMD. We hypothesize that performing later surgery with larger curves would not lead to worse post-operative complications. Retrospective cohort study. Patients with DMD who underwent posterior scoliosis correction, had pre-operative pulmonary function testing, and at least 1-year post-operative follow-up, were included; divided into 2 Groups by pre-operative curve angle – 1: ≤45°, 2: >45°. Primary outcome was post-operative complications by Clavien-Dindo (CD) grading. Secondary outcomes included: age at surgery, forced vital capacity (FVC), steroid utilization, fractional shortening (FS) by echocardiogram, surgery duration, blood transfusion requirements, ICU length of stay (LOS), days intubated post-operatively, hospital LOS, infection, curve correction. Two-tailed t-test and chi-square testing were used for analysis of patient factors and CD complication grade, respectively. 31 patients met the inclusion criteria, with a mean total follow-up of 8.3±3.2 years. Steroid treatment (prednisone, deflazacort) was utilized for 21 (67.7%) patients, for a mean duration of 8.2±4.0 years. Groups were comparable for steroid use, FVC, echo FS, and age at surgery (p>0.05). Primary curve angle was 31.7±10.4° and 58.3±11.1° for Groups 1 and 2, respectively (p 0.05). Surgery duration, ICU LOS, days intubated, hospital LOS, were also not different between Groups. For the entire cohort, however, the overall complication rate was higher for patients with steroid treatment [61.9% vs 10%, respectively (p=0.008)], the majority being CDII. Neither FVC nor echo FS were different between Groups at final follow-up (p=0.6; p=0.4, respectively). Post-operative complication rates were not different for early and late scoliosis correction in DMD. In general, however, patients undergoing steroid treatment were at higher risk of blood transfusion and deep infection. Delaying scoliosis correction in DMD while PF is favourable is reasonable, but patients with prior steroid treatment should be counseled regarding the higher risk of complications

Introduction. The influence of the bone mineral density (BMD) on the mechanical behavior of bones can be examined using computer tomography (CT) data and finite element (FE) simulations, because the BMD correlates with the Hounsfield scale (HU) of the CT data. Therefor the material mapping strategy, which is required to assign the HU values to the FE mesh, is of crucial importance. In this study a nodal mapping strategy was analyzed concerning its sensitivity towards FE mesh parameters and an averaging of HU values from the area around the respective nodes. Method. The FE simulation is based on CT data of a human proximal femur. Once the bone shape was reconstructed, the resulting model was meshed with quadratic tetrahedral elements in ABAQUS/CAE and all nodes were assigned an HU value from the CT data by using the respective node coordinates. In this process, the mesh density, the threshold, which could be used to exclude connective tissue and fat from the material mapping process, the considered volume around the nodes and the method of averaging were varied. The material assignment was realized by an HU value dependent, linear elastic material definition. The femur model was clamped at the level of the isthmus and a displacement of 0.5 mm was applied at the femoral head. The evaluation was based on the resulting reaction forces. Results. The sensitivity analysis demonstrated, that threshold and mesh density mainly influenced the reaction force [Fig. 1]. If a threshold was applied, the reaction force increased by about 20 % in average. A threefold increase of the mesh density led to an average gain of the results of about 24 %. For a specific mesh density the curve progressions of the respective results intersected, i.e. an alteration of the considered volume or the method of averaging barely affected the reaction force [Fig. 2, Fig. 3]. Apart from this intersection, the comparison of the small and the large average volume led to a deviation of up to 11 %. On the other hand, the examination of different methods of averaging revealed only a maximum deviation of 4 % between “mean” and “median”. Discussion. The present study indicates, that the material mapping strategy is an influential part of the modeling process, which should be validated to avoid misjudgments of the load situation. Accordingly, the use of a threshold to exclude non-bone tissue could be a helpful tool. But with the exclusion of lower HU values, the load-bearing structure gains stiffness and the reaction force in the femur rises. A finer mesh leads to a higher resolution of the bone structure and, therefore, to a higher accuracy of the results. The “equilibrium” between the different models at the intersection is caused by a more homogeneous distribution of the material property which is increased by a larger considered volume and the method “mean”