EARLYBIRD: catching the earliest changes of the bone and intervertebral discs in children at increased risk for scoliosis development with MRI - study protocol of a prospective observational cohort study.

introductionAdolescent idiopathic scoliosis (AIS) is an acquired deformity that develops in 2-4% of otherwise healthy children during adolescent growth, substantially reducing their quality of life and creating a life-long burden of disease. Despite many years of dedicated research, the cause and mechanism of AIS are still unknown and no effective curative treatments are available for children suffering from this spinal and chest deformity. To date, all etiological studies focused on children with an already established scoliosis. EARLYBIRD aims to uncover the earliest pathoanatomical changes in AIS, by studying longitudinal spinal growth in children at increased risk for scoliosis development with MRI, starting before adolescence. METHODS AND ANALYSIS: This prospective observational cohort study will follow two groups: 60 adolescent girls (8-10 years old) who have an older sibling or parent diagnosed with AIS (cohort 1) and 60 adolescents with 22q11.2 deletion syndrome, a genetic microdeletion associated with 50% scoliosis prevalence (cohort 2). Data collection will be completely radiation-free and occur at baseline and yearly during adolescence up to 15 years of age in girls and up to 16 in boys. A comprehensive physical examination, a dedicated spine and chest MRI as well as a standing three-dimensional (3-D) spinal ultrasound will be obtained at each time point. The main parameter will be the longitudinal changes in segmental axial rotation during growth in subjects that do and do not develop AIS. Secondary endpoints are longitudinal changes in 3-D morphology of the bone and intervertebral discs (IVDs) during normal spinal development and during scoliosis development, determining biomarkers for bone growth, implementing radiation-free imaging methods for spinal monitoring in adolescent patients at risk for scoliosis development and use these for spinal skeletal maturity and patient-specific spinal biomechanical analyses. ETHICS AND DISSEMINATION: This protocol has been approved by the Medical Ethics Committee NedMed and is registered on clinicaltrials.gov (NCT05924347). Written informed consent will be obtained from all parents/legal representatives. Key findings will be disseminated via peer-reviewed journals and presentation at conferences. This study is funded by the European Research Council.