Preliminary Evaluation of a Computer-Assisted Tool for the Design and Adjustment of Braces in Idiopathic Scoliosis

Abstract

Prospective and randomized clinical study. To evaluate the correction of the spine obtained using a 3-dimensional visualization software tool developed to assist the design and adjustment of braces compared with the correction obtained with the conventional method in a cohort of subjects with adolescent idiopathic scoliosis (AIS). The optimal design and adjustment of trim lines, pad placement, and areas of relief for the Boston brace system in AIS are currently done using clinical examination and coronal radiographs. Correction of spinal curves in the coronal plane has been achieved with this technique, but 3-dimensional correction has yet to be demonstrated. Forty-eight consecutive subjects with AIS requiring treatment with a Boston brace were prospectively entered in the study. For 24 patients (test group), brace design and adjustment was obtained using the computer-assisted tool combining surface topography, surface pressure measurement, and 3-dimensional reconstructions of the trunk, while design and adjustment for the remaining subjects (control group) was done in the conventional manner. Immediate in-brace correction of the spine at the initial visit was compared in both groups. Both groups were comparable in terms of age, sex, curve type, and average deformity in both the coronal and sagittal planes. The average prebrace thoracic deformity was 35 degrees of Cobb angle, while the average lumbar curve was 32 degrees in the test group and 35 degrees in controls. A statistically and clinically significant improvement in correction of coronal curves and of curves in the plane of maximal deformity was found for both thoracic and lumbar curves in both groups, but the improvement was significantly greater in the test group. The average in-brace correction in the test group was 12 degrees +/- 7 degrees compared with 7 degrees +/- 5 degrees in the control group for thoracic curves, while the average in-brace correction in the test group was 10 degrees +/- 5 degrees compared with 6 degrees +/- 5 degrees in the control group for lumbar curves. Similar average corrections were detected in the plane of maximal deformity. In addition, a significant improvement in the orientation of the plane of maximum deformity from 37 degrees to 23 degrees for lumbar curves was noted only in the test group, indicating that true 3-dimensional correction by the brace was obtained in this group. It is possible to improve the design and adjustment of braces in AIS and to achieve 3-dimensional correction of scoliotic curves with the use of a computer-assisted tool allowing 3-dimensional visualization of the spinal curves and the external shape of the trunk.