The position of the abdominal aorta relative to lumbar vertebrae in patients with degenerative lumbar scoliosis

English Keywords:Degenerative lumbar scoliosis  Abdominal aorta  Aorta-vertebrae angle  Aorta-vertebrae distance  Rotation angle

English Abstract:

  【Abstract】 Objectives: To investigate the anatomic position of the abdominal aorta relative to spine in degenerative lumbar scoliosis(DLS) patients with left or right lumbar scoliosis. Methods: A retrospective analysis was performed in 142 patients with DLS and 132 patients without spine deformity(control group) from January 2015 to June 2018 in our hospital. The DLS patients were divided into 80 cases with left lumbar scoliosis(left group) and 62 cases of right scoliosis(right group), which were matched to control group in terms of gender, age and body mass index(BMI). Direction of lumbar scoliosis(left or right), Cobb angle, apical vertebra position and coronal trunk shift were measured by using X-ray plain radiography in DLS patients. The measurements of aorta-vertebra angle(α), rotation angle(γ), aorta-vertebra distance(d) and the interval between anterior vertebral cortex and posterior aorta wall(Int) for each level at T12-L4 were obtained by using a Cartesian coordinate system established based on T1-weighted cross-sectional images of MRI. Independent sample t test was performed on comparison of α, γ, d and Int between the left group and control group, as well as the right group and control group, then Pearson correlation analysis was used to investigate the association between the Cobb angle and the coronal and α, γ, d and Int of the two scoliosis groups. Results: The average Cobb angle was 23.7°±12.7°(10.4°-42.5°) and the coronal horizontal displacement distance was 45.2±10.7mm(25.5-77.7mm) in the left group while they were 20.8°±10.4°(11.0°-48.4°) and 47.8±15.1mm(25.4-77.5mm) respectively in the right group, and there were no statistical differences in the apical vertebra position(P=0.280), Cobb angle(P=0.311) and coronal trunk shift(P=0.394) between the two scoliosis groups. The mean angle α(-2.96°±6.40°) gradually decreased from T12 to L4 in the control group while irregular in the left group(-2.57°±6.14°) and there was no difference between the two groups(P=0.554). The mean γ was 5.57°±5.32° and the mean d was 4.62±0.57cm with a gradual increase from T12 to L4 and with statistical difference with control group(4.44±0.43cm)(P<0.001) but with no difference in Int(P=0.832). Thus, the abdominal aorta had no statistical angle change but a slightly longer distance away from lumbar vertebrae in left scoliosis compared with the normal ones. That mean α (-3.41°±9.44°) gradually decreasing from T12 to L4 in right group was of no statistical difference with the control group(P=0.762). The mean γ was -9.02°±6.71° and the mean d was 4.54±1.84cm, with no difference with the control group(P=0.530) as well as Int(P=0.807). Therefore, there was no significant variation in the angle and distance between the abdominal aorta and vertebrae in right curvature of DLS compared with the control group. Pearson correlation analysis showed that there was a correlation between rotation angle γ and Cobb angle along with coronal horizontal displacement distance(both P<0.001), regardless of the left or right scoliosis, but not in α, d and Int. Conclusions: In the right group, a relative normal position relationship is maintained between the abdominal aorta and vertebrae while the aorta is slightly away from the left pedicle in left scoliosis patients. Although not so much difference of the relative position between DLS and normal people is found in this study, it is still of necessity to be alert to aorta injury.