Defining indications and outcomes of brace treatment for adolescent idiopathic scoliosis

Dr Cheung, Jason Pui Yin   (Principal Investigator (PI))

24

2020-06-30

2022-06-29

83200

Defining indications and outcomes of brace treatment for adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis, bracing, Cobb angle, outcomes

Orthopaedics/Traumatology

201910159031

Seed Fund for PI Research – Basic Research

2019

Completed

Scoliosis is a 3-dimensional deformity characterized as a lateral curvature of the spine. Its most common form occurs during adolescence and is commonly known as adolescent idiopathic scoliosis (AIS). Based on the Hong Kong scoliosis school screening data (comprising of 78% of the total student population), up to 2.2% of boys and 4.8% of girls have scoliosis. It is thus, the most common spine condition in the pediatric population. Progression of AIS occurs with natural growth. Without prompt intervention, this deformity may deteriorate and result in cosmetic disfigurement, back pain and cardiopulmonary compromise in severe cases. Worsened spine curvature may also cause stigmatization and poor self-esteem in these young children. Bracing is the mainstay treatment for preventing AIS progression and the main purpose for treatment is to prevent deformities from reaching the surgical threshold. It has been shown to be effective at reducing curve progression especially in patients with good compliance to treatment. However, bracing should not be used indiscriminately as certain complications have been reported. Bracing too early is safe for curve control but may subject children to prolonged discomfort with the bracing and increased consumption of resources for periodic brace fabrication. Prolonged bracing also reduces spinal mobility, lead to poor body image and self-esteem, and worsen quality of life. Additional risks of osteoporosis and muscular atrophy may also occur. Hence, being able to initiate prompt and appropriate bracing is crucial for achieving optimal curve control and avoiding complications. Yet, we still have difficulties identifying patients who may deteriorate and also determining the likely outcomes on different brace groups at skeletal maturity and the resulting relationship between curve magnitude and health-related quality of life (HRQOL) measures. As such, the relationship of the Cobb angle prior to initiating brace treatment with long-term HRQOL measures is unknown. Furthermore, in what patients do we expect better outcomes of curve regression and curve correction is not well-established. The roles of curve flexibility and brace-fitting are unknown. Supine radiographs are commonly obtained for our study population as it helps with planning for brace fabrication. It is reliable and reproducible to assess spinal flexibility specifically for the purpose of brace fitting.(1) These images are obtained passively as patients do not require any effort to lie supine. They are also in the identical posture as in standing unlike side-bending or fulcrum-bending radiographs, which is the posture patients adopt while in brace. Its predictability of curve progression is unknown and is a main objective of this study. Better in-brace correction may influence the end of treatment Cobb angle(2) and at long-term follow-up(3). However, this relationship and factors associated with changes after brace treatment are not well understood. Well-fitting braces may induce vertebral remodeling, as evidenced by changes in the curve pattern(4). Based on Hueter-Volkman’s law(5), we suspect that patients with good in-brace correction may have improved curvature. This has a strong interplay with curve flexibility and ultimately will improve patient outcomes with brace treatment. Nevertheless, the above suggest that there is a significant gap in our knowledge of the optimal timing of brace initiation for managing AIS patients and the predictive prognostic features that can be identified at baseline. Hence, the main objectives of this study are: 1. To assess the efficacy and cost-effectiveness of current bracing protocols for AIS. 2. To determine the likelihood of curve regression and curve progression with bracing. 3. To determine the influence of flexibility on bracing outcomes. 4. To create a mathematical model that will determine the most cost-effective threshold for initiating brace treatment based on health quality of life measures.