EFFECT OF PATIENT POSITION ON THE SAGITTAL-PLANE PROFILE OF THE THORACOLUMBAR SPINE

Although the normal sagittal profile of the thoracolumbar spine has be en described, this has been obtained primarily by using young individu als standing. We sought to describe the sagittal profile of the thorac olumbar spine in an older population in the supine cross-table lateral position compared with that standing. We enrolled 50 volunteers with no history of back pain or spine deformity and 50 matched subjects wit h mechanical back pain (LBP) only. Lateral radiographs of the thoracol umbar spine (T10-S1) in both standing and cross-table supine positions were obtained. Lordosis from L1 to S1, kyphosis from T10 to L1, and t he changes seen moving from the supine position to standing were calcu lated. There were few differences comparing the two groups in either t he standing or cross-table supine position, or when changing positions . Within each group, however, there were small, but significant, diffe rences in the midlumbar and thoracolumbar spine when comparing supine versus standing. Both asymptomatic individuals and those with a histor y of LBP demonstrated similar small but statistically significant incr eases in lumbar lordosis and thoracolumbar kyphosis when standing vers us supine, The clinical significance of these findings remains to be d etermined.