Braces Designed Using CAD/CAM Combined or Not With Finite Element Modeling Lead to Effective Treatment and Quality of Life After 2 Years : A Randomized Controlled Trial

Study Design. Single-center prospective randomized controlled trial.

Objective. The aim of this study was to assess the computer-aided design/manufacturing (CAD/CAM) brace design approach, with and without added finite element modeling (FEM) simulations, after 2 years in terms of clinical outcomes, 3D correction, compliance, and quality of life (QoL).

Summary of Background Data.. Previous studies demonstrated that braces designed using a combination of CAD/CAM and FEM induced promising in-brace corrections, were lighter, thinner, and covered less trunk surface. Yet, their long-term impact on treatment quality has not been evaluated.

Methods. One-hundred twenty adolescent idiopathic scoliosis patients were recruited following Scoliosis Research Society standardized criteria for brace treatment; 61 patients in the first subgroup (CAD) were given braces designed using CAD/CAM; 59 in the second subgroup (CAD-FEM) received braces additionally simulated and refined using a patient-specific FEM built from 3D reconstructions of the spine, rib cage and pelvis. Main thoracic (MT) and thoraco-lumbar/lumbar (TL/L) Cobb angles, sagittal curves, and apical rotations were compared at the initial visit and after 2 years. Patient compliance and QoL were tracked respectively by using embedded temperature sensors and SRS-22r questionnaires.

Results. Forty-four patients with CAD-FEM braces and 50 with CAD braces completed the study. Average in-brace correction was 9° MT (8° CAD-FEM, 10° CAD, P = 0.054) and 12° TL/L (same for both subgroups, P = 0.91). Out-of-brace 2-year progression from initial deformity was <4° for all 3D measurements. Sixty-six percent of all cases (30 CAD-FEM, 35 CAD) met the ≤5° curve progression criterion, 83% (38 CAD-FEM, 43 CAD) stayed <45°, and 6% (5 CAD-FEM, 1 CAD) underwent fusion surgery. 3D correction, compliance, and QoL were not significantly different between both subgroups (P > 0.05).

Conclusion. After 2 years, patients with braces designed using CAD/CAM with/without FEM had satisfying clinical outcomes (compared to the BrAIST study), 3D corrections, compliance and QoL. A more comprehensive optimization of brace treatment remains to be accomplished.

Level of Evidence: 2

Uncontrolled Keywords

• 3D correction
• adherence
• adolescent idiopathic scoliosis (AIS)
• brace simulation
• brace-wear compliance
• bracing
• computer-assisted design and manufacturing (CAD/CAM)
• finite element modeling (FEM)
• quality of life
• randomized controlled trial (RCT)