Evaluating Interface Pressure Distribution and Range of Motion in a Mesh-Structure 3D-Printed Lumbar Brace

Conventional spinal braces often suffer from poor fit and low breathability, with most 3D-printing research focusing on scoliosis rather than general support. This study evaluated the biomechanical performance and range of motion (ROM) restriction of a semi-custom 3D-printed brace (3DP) compared with two traditional braces (Medi-H, Medi-S). Sixteen participants performed static standing, flexion, extension, and pick-up tasks while wearing each brace. Interface pressure was recorded across seven anatomical regions, and thoracic (C7-T8) and lumbar (T8-L3) ROM were assessed simultaneously using repeated-measures ANOVA. Results showed that 3DP and Medi-H provided significantly greater overall pressures than Medi-S. During flexion and pick-up tasks, 3DP delivered enhanced support to the middle lumbar region and erector spinae, whereas Medi-H concentrated greater pressure on the spine, particularly during extension. Thoracic and lumbar ROM were restricted comparably across all braces (20-30°). In conclusion, 3DP achieves an equivalent restriction of sagittal motion to traditional braces while offering superior regional support to the upper and middle lumbar regions.