OBJECTIVESTo explore the clinical significance of the transverse thoracic pedicle diameters measurement and thoracic pedicles classification in thoracic adolescent idiopathic scoliosis patients.

METHODSThirty thoracic idiopathic scoliosis patients who were hospitalized during October 2008 and July 2009 and 20 non-scoliosis adolescents who were adopted during August 2008 and July 2009 were included in this study. Successive CT thoracic vertebrae scanning of all subjects were obtained. All participants' transverse pedicle diameters of the thoracic vertebrae were measured with the software of PACS Client. Classified the pedicle into 4 types according to the transverse pedicle diameters. In control group, the transverse pedicle diameters of bilateral thoracic vertebrae were compared using paired-t test. In AIS group, the transverse pedicle diameters of concave and convex side thoracic vertebrae were compared using paired-t test. The distribution of pedicle types were compared using Chi-Square test between the control group and AIS group.

RESULTSThe transverse pedicle diameters showed a decreasing trend from T(1) to T(4) followed by an increasing trend from T(5) to T(12) in both groups. The bilateral transverse pedicle diameters had no significant difference in the control group. The transverse pedicle diameters of the concave side at the apex of thoracic curve were found to be significantly thinner than those of convex side. The ratio of Type 4 was higher in thoracic adolescent idiopathic scoliosis patients than the controls, and the ratio of Type 1 was smaller in thoracic adolescent idiopathic scoliosis patients than the controls.

CONCLUSIONSThe thoracic pedicles in thoracic adolescent idiopathic scoliosis patients are often rather thinner. Preoperative CT measurement of thoracic pedicle in the treatment of idiopathic scoliosis is suggested helpful in deciding the correct strategy of pedicle screw insertion and decreasing the risk of clinically relevant neurovascular complications.