The measurement and significance of heart-sacral angles in normal Han nationality adults in China

English Keywords:Heart-sacral angle  Spine  Sagittal balance  Coronal balance  Radiography

English Abstract:

  【Abstract】 Objectives: To measure a new spine-internal organ parameter: heart-sacral angle, in full length, free-standing spine radiograph, and to compare the differences between genders and ages and the clinical values. Methods: A prospective cohort of 108 normal Han nationality adults in China were divided into 4 groups: Group 1(18-44y, males); Group 2(45-60y, males); Group 3(18-44y, females); Group 4(45-60y, females). Coronal heart-sacral angle was defined as the angle between a vertical line through the midpoint of S1 endplate and a line connecting the midpoint of S1 endplate to the outermost point of heart in full length, free-standing posteroanteriorspine radiographs. Sagittal heart-sacral angle defined as the angle between a vertical line through the midpoint of S1 endplate and a line connecting the midpoint of S1 endplate to the forefront point of heart in full length, free-standing lateralspine radiographs. One-way Anova test was used to compare the angle differences among 4 groups. Two-sample t-test was used to compare the angle differences between genders. Introclass correlation coefficient(ICC) was used to reflect the consistency of measurements by the same observer, among the three observers and repeatability of the three measurements by three observers. Results: Coronal heart-sacral angle was Group 1, 19.6°±2.8°; Group 2, 20.6°±3.5°; Group 3, 19.5°±3.6°; Group 4, 20.8°±2.3°. Sagittal heart-sacral angle was Group 1, 17.0°±4.4°; Group 2, 16.7°±4.3°; Group 3, 14.7°±3.5°; Group 4, 16.3°±4.8°. There were no significant differences in coronal and sagittal heart-sacral angles among 4 groups and between genders(P>0.05). ICC of the consistency of measurements by the same observer, among the three observers and repeatability of the three measurements by three observers wasbetween 0.89-0.98(P<0.05). Conclusions: Heart-sacral angles in normal Han nationality adults in China are anatomical constants with good reliability and reproducibility, it can be used as spine-internal organ parameters to evaluate the coronal and sagittal balances of spine.