OBJECTIVETo measurement the vertebra morphology using multi-planar reformations method of multi-slice spiral CT (MSCT) in AIS girls, and To compare with age and gender-matched controls in order to affirm the morphology results of abnormal development of the anterior and posterior elements in AIS.

METHODSThoracic and lumbar spine multi-slice spiral CT was undertaken on 52 girls with AIS between the age of 10 and 18 years from June 2004 to May 2008 in Peking Union Medical College Hospital and Beijing Shijitan Hospital, and 54 age and gender-matched non-IS controls. Multiple measurements (including the anterior column and posterior column) of each thoracic and lumbar vertebra were obtained using the 3D-MPR technique. The patients and control were divided into 10-14 years old group and 15-18 years old group. The corresponding vertebral anterior height, vertebral posterior height, transverse distance, vertebra central width, vertebra anterior-posterior distance, area of pedicle, pedicle height, pedicle width, and upper-lower facet distance were compared.

RESULTSCompared with the controls, the 10-14 years old group girls' spine had longer anterior column height, relative shorter posterior column (there are difference from thoracic 2-11 and lumbar 1-3, P < 0.05), relative longer anterior-posterior vertebral distance, vertebral wedging changes in vertebral, distinct vertebral and pedicle asymmetry on the concave and convex side, and upper-lower facet distance asymmetry on the concave and convex side. The difference between the anterior and the posterior column ratio was significantly different from that in the controls (P < 0.01). But there hadn't the same difference in 15 - 18 years old group.

CONCLUSIONSThere are differences in coronal plane vertebra wedging changes in AIS patient. There are high vertebra height, relative shorter posterior column, relative longer anterior-posterior vertebral distance, and relative slender vertebra in 10 - 14 years old AIS patients. This may lead to the initial and progression of scoliosis.