Head to pelvis alignment of adolescent idiopathic scoliosis patients both in and out of brace

Abstract

Purpose: To determine the short-term effect of bracing of adolescent idiopathic scoliotic (AIS) patients on the relationships between spinopelvic parameters related to balance, by comparing their in and out-of-brace geometry and versus healthy subjects.

Methods: Forty-two AIS patients (Cobb angle 29° ± 12°, ranging from 16° to 61°) with a prescription of orthotic treatment were included retrospectively and prospectively. They all underwent biplanar radiography and 3D reconstruction of the spine and pelvis before bracing as well as less than 9 months after bracing. Eighty-three age-matched healthy adolescents were also included as control group and underwent biplanar radiography and 3D reconstruction.

Results: Sacral slope was higher in AIS than healthy patients (p = 0.005). Bracing induced large changes of pelvic tilt (between - 9° and 9°), although patients' sagittal spinopelvic alignment tended to remain within the normality corridors defined by the healthy patients. Patients had flatter backs compared to healthy subjects and bracing further reduced their spinal curves. The head tended to remain above the pelvis in-brace.

Conclusion: Analysis of sagittal alignment from head to pelvis showed that bracing further flattened the patients' backs and induced large compensating reorientations of the pelvis. Sagittal balance should be included in the planning and evaluation of brace treatment, since it could play a role in its outcome. These slides can be retrieved under Electronic Supplementary Material.

Keywords: AIS; Brace effect; Bracing; Compensation; Sagittal balance.