https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 09 Mar 2026 02:37:56 GMT 2026-03-09T02:37:56Z http://hdl.handle.net/10985/20219 Comparison of 3D and 2D characterization of spinal geometry from biplanar X-rays: a large cohort study HU, Zongshan; VERGARI, Claudio; GAJNY, Laurent; LIU, Zhen; LAM, Tsz-Ping; ZHU, Zezhang; QIU, Yong; MAN, Gene C. W.; YEUNG, Kwong-Hang; CHU, Winnie C. W.; CHENG, Jack C. Y.; SKALLI, Wafa Background: Biplanar X-ray system providing anteroposterior and sagittal plane with an ultra-low radiation dose and in weight-bearing position is increasingly used for spine imaging. The original three-dimensional (3D) reconstruction method from biplanar X-rays has been widely used for clinical parameters, however, the main issue is that manual adjustments of the 3D model was quite time-consuming and limited to thoracolumbar spine. A quasi-automated 3D reconstruction method of the spine from cervical vertebra to pelvis was proposed, which proved fast and accurate in 57 patients with adolescent idiopathic scoliosis. The aim of this study was to compare the newly developed technique of quasi-automatic 3D measurement with classical 2D measurements in a large cohort. Methods: A total of 494 adults with biplanar EOS X-ray scanning were included in this study and divided into health and deformity group according to the presence of spinal deformity. The proposed method of quasi-automatic 3D measurement was applied to all these subjects. The radiographic parameters included: thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), T1 pelvic angle (TPA) in sagittal plane, and cobb angle in coronal plane. Comparison was made between quasi-automatic and manual measurement. Results: The mean age was 53.7±19.9 years old. In the whole population, the mean differences between the two methods were 3.9° for TK (30.5°±9.9° vs. 26.5°±9.3°, P<0.001), –5.2° for LL (–47.5°±11.2° vs. –42.4°±11.0°, P<0.001), 3.6° for PI (46.9°±10.3° vs. 43.9°±10.3°, P<0.001), –0.2° for PT (11.9°±7.7° vs. 12.0°±8.2°, P=0.328), –2.1 mm for SVA (15.7±26.2 vs. 17.8±26.3 mm, P=0.221) and –1.1° for TPA (9.0°±7.6° vs. 10.1°±7.8°, P=0.051). The deformity group had similar mean differences with the asymptomatic group with the values ranged from –4.1° to 3.8° for sagittal parameters. The mean differences of Cobb angle were 1.9° for patients with Cobb angle <30° and 2.3° for patients with Cobb angle >30°, respectively. Correlation analysis showed r2 for all clinical parameters ranged from 0.667 to 0.923. On average, the new method takes 5 minutes to compute all the parameters for one case. Conclusions: In conclusion, this ergonomic and efficient quasi-automatic method for full spine proved fast and accurate measurement in a large population, which showed great potential in extensive clinical application Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20219 2021-01-01T00:00:00Z HU, Zongshan VERGARI, Claudio GAJNY, Laurent LIU, Zhen LAM, Tsz-Ping ZHU, Zezhang QIU, Yong MAN, Gene C. W. YEUNG, Kwong-Hang CHU, Winnie C. W. CHENG, Jack C. Y. SKALLI, Wafa Background: Biplanar X-ray system providing anteroposterior and sagittal plane with an ultra-low radiation dose and in weight-bearing position is increasingly used for spine imaging. The original three-dimensional (3D) reconstruction method from biplanar X-rays has been widely used for clinical parameters, however, the main issue is that manual adjustments of the 3D model was quite time-consuming and limited to thoracolumbar spine. A quasi-automated 3D reconstruction method of the spine from cervical vertebra to pelvis was proposed, which proved fast and accurate in 57 patients with adolescent idiopathic scoliosis. The aim of this study was to compare the newly developed technique of quasi-automatic 3D measurement with classical 2D measurements in a large cohort. Methods: A total of 494 adults with biplanar EOS X-ray scanning were included in this study and divided into health and deformity group according to the presence of spinal deformity. The proposed method of quasi-automatic 3D measurement was applied to all these subjects. The radiographic parameters included: thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sagittal vertical axis (SVA), T1 pelvic angle (TPA) in sagittal plane, and cobb angle in coronal plane. Comparison was made between quasi-automatic and manual measurement. Results: The mean age was 53.7±19.9 years old. In the whole population, the mean differences between the two methods were 3.9° for TK (30.5°±9.9° vs. 26.5°±9.3°, P<0.001), –5.2° for LL (–47.5°±11.2° vs. –42.4°±11.0°, P<0.001), 3.6° for PI (46.9°±10.3° vs. 43.9°±10.3°, P<0.001), –0.2° for PT (11.9°±7.7° vs. 12.0°±8.2°, P=0.328), –2.1 mm for SVA (15.7±26.2 vs. 17.8±26.3 mm, P=0.221) and –1.1° for TPA (9.0°±7.6° vs. 10.1°±7.8°, P=0.051). The deformity group had similar mean differences with the asymptomatic group with the values ranged from –4.1° to 3.8° for sagittal parameters. The mean differences of Cobb angle were 1.9° for patients with Cobb angle <30° and 2.3° for patients with Cobb angle >30°, respectively. Correlation analysis showed r2 for all clinical parameters ranged from 0.667 to 0.923. On average, the new method takes 5 minutes to compute all the parameters for one case. Conclusions: In conclusion, this ergonomic and efficient quasi-automatic method for full spine proved fast and accurate measurement in a large population, which showed great potential in extensive clinical application http://hdl.handle.net/10985/21635 An analysis on the determinants of head to pelvic balance in a Chinese adult population HU, Zongshan; VERGARI, Claudio; GAJNY, Laurent; MAN, Gene Chi-Wai; YEUNG, Kwong-Hang; LIU, Zhen; LAM, Tsz-Ping; ZHU, Zezhang; QIU, Yong; CHU, Winnie Chiu-Wing; CHENG, Jack Chun-Yiu; SKALLI, Wafa Background: Balanced global spinopelvic balance is important in the maintenance of the physiological alignment of all body segments above the pelvis with minimum energy expenditure. The key determinants affecting the 3D index-odontoid-hip axis (OD-HA) angle, and in particular its alterations, have not been clearly defined. The aim of this study is to identify the determinants of the 3D OD-HA angle in maintaining global spinopelvic balance in a large Chinese adult cohort of different gender and age groups. Methods: A total of 516 asymptomatic adults were enrolled in this study. Biplanar radiographies were performed to reconstruct the subject’s inter-acetabular axis and C2 odontoid process. The 3D angle formed by the vertical and the line between odontoid and mid-interacetabular axis (OD-HA angle) was computed and projected in the subject’s sagittal and coronal planes. Thoracic kyphosis (TK), lumbar lordosis (LL), T1 pelvic angle (TPA) and sagittal vertical axis (SVA) were measured. Results: The mean values of sagittal and coronal OD-HA were −0.2°±2.5° and 0.2°±1.1°, respectively. Both sagittal and coronal OD-HA had significant correlation with age (r=0.265 and r=−0.143, P<0.01, respectively), sagittal OD-HA showed increment from 20s to 80s (−1.3° to 0.8° for female, −0.3° to 1.5° for male) and a significant difference between male and female from 20 to 69 years old. Further analysis showed that sex, weight, TK, PT, SVA, TPA and ODI were determinants of OD-HA. Conclusions: 3D OD-HA angle showed physiological stability with little variability from young to elderly adults, with SD of 2.45° and 1.06° in sagittal and coronal planes, respectively. OD-HA angle confirms the hypothesis that the head tends to remain above the pelvis in a small cone of stability. This study provides an analysis of the determinants of OD-HA and the reference range of the head-pelvis balance in each decade and gender based on a large-scale asymptomatic population. Sat, 01 Jan 2022 00:00:00 GMT http://hdl.handle.net/10985/21635 2022-01-01T00:00:00Z HU, Zongshan VERGARI, Claudio GAJNY, Laurent MAN, Gene Chi-Wai YEUNG, Kwong-Hang LIU, Zhen LAM, Tsz-Ping ZHU, Zezhang QIU, Yong CHU, Winnie Chiu-Wing CHENG, Jack Chun-Yiu SKALLI, Wafa Background: Balanced global spinopelvic balance is important in the maintenance of the physiological alignment of all body segments above the pelvis with minimum energy expenditure. The key determinants affecting the 3D index-odontoid-hip axis (OD-HA) angle, and in particular its alterations, have not been clearly defined. The aim of this study is to identify the determinants of the 3D OD-HA angle in maintaining global spinopelvic balance in a large Chinese adult cohort of different gender and age groups. Methods: A total of 516 asymptomatic adults were enrolled in this study. Biplanar radiographies were performed to reconstruct the subject’s inter-acetabular axis and C2 odontoid process. The 3D angle formed by the vertical and the line between odontoid and mid-interacetabular axis (OD-HA angle) was computed and projected in the subject’s sagittal and coronal planes. Thoracic kyphosis (TK), lumbar lordosis (LL), T1 pelvic angle (TPA) and sagittal vertical axis (SVA) were measured. Results: The mean values of sagittal and coronal OD-HA were −0.2°±2.5° and 0.2°±1.1°, respectively. Both sagittal and coronal OD-HA had significant correlation with age (r=0.265 and r=−0.143, P<0.01, respectively), sagittal OD-HA showed increment from 20s to 80s (−1.3° to 0.8° for female, −0.3° to 1.5° for male) and a significant difference between male and female from 20 to 69 years old. Further analysis showed that sex, weight, TK, PT, SVA, TPA and ODI were determinants of OD-HA. Conclusions: 3D OD-HA angle showed physiological stability with little variability from young to elderly adults, with SD of 2.45° and 1.06° in sagittal and coronal planes, respectively. OD-HA angle confirms the hypothesis that the head tends to remain above the pelvis in a small cone of stability. This study provides an analysis of the determinants of OD-HA and the reference range of the head-pelvis balance in each decade and gender based on a large-scale asymptomatic population.