Imaging study of sagittal alignment changes caused by post-traumatic kyphosis secondary to old thoracolumbar fractures

Abstract

Objective To compare the Roussouly classification of old thoracolumbar fractures combined with post-traumatic kyphosis with that of normal adults, evaluate the effect of different kyphosis angles on sagittal curvature of the thoracolumbar spine so as to provide a theoretical basis for the clinical status and clinical treatment plan of old thoracolumbar fractures combined with post-traumatic kyphosis. Methods A retrospective case control study was made on 49 cases of old thoracolumbar fractures with post-traumatic kyphosis treated from January 2014 to December 2015 (fracture group). Damaged segments of the spine were T11 in four cases, T12 in 14, L1 in 25 and L2 in six. Another 52 normal adult volunteers were chosen as controls. Whole spine X-ray film of the two groups was taken, and the difference in Roussouly classification of the sagittal spine curvature was compared between the two groups. Patients in fracture group were separated into subgroups depending on the Cobb angle (0°-10°, 10°-20°, 20°-30°, 30°-40°, respectively), and the difference in Roussouly classification was compared among subgroups. Results Roussouly classification in control group was five cases of type 1, 12 tpye 2, 25 type 3 and 10 type 4. Results in fracture group was 14 cases of type 1, 11 type 2, eight type 3 and 16 type 4. There were significant differences in Roussouly types between the two groups (P 20° (P<0.05). Conclusions Post-traumatic kyphosis in old thoracolumbar fractures affects spine sagittal curvature. Patients with sagittal spinal imbalance (Roussouly types 1 and 2) are more with increased Cobb angle. Moreover, Cobb angle >20°may be the reference basis for clinical intervention. Key words: Kyphosis; Thoracic vertebrae; Lumbar vertebrae; Roussouly type