Article

Adolescent idiopathic scoliosis is a complex three-dimensional
deformity, involving a lateral deformity in the coronal plane and axial rotation
of the vertebrae in the transverse plane. Gravitational loading plays an
important biomechanical role in governing the coronal deformity, however, less is
known about how they influence the axial deformity. This study investigates the
change in three-dimensional deformity of a series of scoliosis patients due to
compressive axial loading. METHODS: Magnetic resonance imaging scans were
obtained and coronal deformity (measured using the coronal Cobb angle) and axial
rotations measured for a group of 18 scoliosis patients (Mean major Cobb angle
was 43.4(o)). Each patient was scanned in an unloaded and loaded condition while
compressive loads equivalent to 50% body mass were applied using a custom
developed compressive device. FINDINGS: The mean increase in major Cobb angle due
to compressive loading was 7.4(o) (SD 3.5(o)). The most axially rotated vertebra
was observed at the apex of the structural curve and the largest average
intravertebral rotations were observed toward the limits of the coronal
deformity. A level-wise comparison showed no significant difference between the
average loaded and unloaded vertebral axial rotations (intra-observer
error=2.56(o)) or intravertebral rotations at each spinal level. INTERPRETATION:
This study suggests that the biomechanical effects of axial loading primarily
influence the coronal deformity, with no significant change in vertebral axial
rotation or intravertebral rotation observed between the unloaded and loaded
condition. However, the magnitude of changes in vertebral rotation with
compressive loading may have been too small to detect given the resolution of the
current technique.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS