The Position Of The Aorta Relative To The Spine In Patients With Thoracolumbar Kyphosis Secondary To Ankylosing Spondylitis And The Risk Analysis Of Aortic Injury Resulting From Lumbar Spinal Osteotomy

Part one:The position of the aorta relative to the spine in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis and the risk analysis of aortic injury resulting from lumbar spinal osteotomyObjectives To explore the anatomic relationship between theaorta and the spine in patients with thoracolumbar kyphosis secondary to ankylosing spondylitis (AS).Methods Thirty-three patients with AS with thoracolumbar kyphosis and 38 age-and sex-matched patients with a normal spine were included in this study. For each subject, the left pedicle-aorta angle and distance were measured from T9 to L3 on the computed tomographic scans. Radiographs were analyzed to measure the global kyphosis, lumbar lordosis, and to record the apex of the kyphotic curve.Result At T9-L3 levels, patients with AS with thoracolumbar kyphosis exhibited signifi cantly smaller left pedicle-aorta angles (from 10.23° to-11.56°) and larger distances (from 39.0 to 55.5 mm) than those with a normal spine. With increased global kyphosis, the aorta shifted more laterally to the right at periapical levels (L1 and L2, P< 0.05). Notably, the aorta was located at the middle front of the vertebrae at T12-L1 levels and far away from the vertebrae at L2 and L3 levels.Conclusion In patients with AS with thoracolumbar kyphosis, the aorta is positioned more anteromedially relative to the vertebral body than that in the normal subjects. The aorta is far away from the vertebral body at L2 and L3 levels, thus it could be much safer to perform osteotomy below L1.Part two:Correlation and clinical significance of the decreased cervical mobility in ankylosing spondylitis patients with thoracolumbar kyphosisObjectives To analysis the correlated factors of the limited cervical range of motion in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis and its clinical relevance.Methods From May 2012 to October 2012, thirty eight AS patients (with complete medical records) were enrolled from the 51 consecutive AS patients with thoracolumbar kyphosis in our hospital. There were 36 males and 2 females, with an average age of 32.6 years (range,17-53 years). The clinical data consisted of age and disease duration, erythrocyte sedimentation rate (ESR), C-reaction protein (CRP). The radiographic parameters were composed by global kyphosis (GK), cervical mSASSS (the modified Stokes ankylosing spondylitis spinal score), cervical curve, and C2-C7SVA. The quality of life questionnaires consisted of bath ankylosing spondylitis disease activity index (BASDAI), bath ankylosing spondylitis functional index (BASFI), and Oswestry disability index (ODI). According to the value of CROM,the subjects were divided into two groups:Group A, CROM>40°; and Group B, CROM<20°. The independent t-test were used to compare the parameters between two groups. Furthermore, the Pearson correlation test were performed to investigate the risk factors correlated with CROM.Results In Group A, there were 16 patients and the average CROM were 65.8±14.3°(41°-92°), while 17 patients in the Group B and the average CROM were 9.2±6.6°(1°-20°). With respect to the disease duration, BASFI, GK, mSASSS, cervical curve and C2-C7 the SVA, a significant difference was found between the two groups (P<0.05). In contrast, the age, ODI, BASDAI, ESR or CRP had no significant difference between Group A and Group B (P>0.05). There were remarkable correlations between CROM and disease duration, mSASSS, cervical curve, C2-C7 SVA and BASFI (r=-0.524,-0.895,0.494,-0.813, and -0.501 respectively, P< 0.05). It’s worth noting that there was no significant correlation between GK and CROM (r=-0.275, P=0.122).Conclusion Longer disease duration and cervical structural damage are high risk factors of CROM in AS patients with thoracolumbar kyphosis. AS patients’ quality of life were severe affected by the limited cervical range of motion.