Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube City, Yamaguchi Prefecture 755-8505, Japan.
Vehicle Development Division, Crash Safety Development Department, Mazda Motor Corporation, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture 730-8670, Japan.
Spine J. 2020 Apr;20(4):614-620. doi: 10.1016/j.spinee.2019.11.016. Epub 2019 Dec 9.
Studies of the changes in spine alignment in the sitting position have been limited to specific spine segments. Because there have been few studies of global spinopelvic alignment in the sitting position, it is important to assess the changes associated with this position for such settings as developing future design of seats and achieving appropriate restoration of spine alignment.
This study aimed to measure changes in global spine alignment when people are sitting in car seats and to analyze the characteristics of those changes.
This was a prospective, collaborative study of the radiological evaluation of changes in global spine alignment.
The study included 113 asymptomatic adult participants (56 men and 57 women) without a history of spine disease or lower limb surgery, and with no current lower back or leg pain.
Radiographic findings were assessed by measurement of various angles: cervical lordosis (CL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), C7 sagittal vertical axis (C7-SVA), T1 spinopelvic inclination (T1SPI), and T1 pelvic angle (TPA).
Radiographs were obtained in the standing and sitting positions. The objective variables analyzed statistically were spine alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, PT, and PI) measured in the standing position, body alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, and PT) measured in the sitting position, and stand-to-sit changes (∆CL, ∆TK, ∆TLK, ∆LL, ∆C7-SVA, ∆T1SPI, ∆TPA, ∆SS, and ∆PT). Explanatory variables were sex, age, body height, and body mass index.
Changing posture from standing to sitting decreased CL by an average of 5.3°, slightly decreased TK by an average of 1.3°, increased TLK by an average of 6.8°, decreased LL by an average of 35°, decreased SS by an average of 49.2°, increased PT by an average of 49.2°, shifted C7-SVA backward by an average of 106.7 mm, decreased T1SPI by an average of 18.8°, and increased TPA by an average of 21.1°. Statistical analysis revealed that ΔLL was significantly decreased in elderly participants. After the stand-to-sit change, ΔTLK and ∆TPA were significantly increased in taller participants and ΔT1SPI was significantly decreased in taller participants.
Among other changes, most notably LL is decreased and the pelvic tilt is increased when a person is sitting in a car seat. However, these changes in spine alignment differ with age and height. These findings may be useful for the development of future design of seats and for achieving appropriate surgical restoration of spine alignment.
对坐姿脊柱排列变化的研究仅限于特定的脊柱节段。由于对坐姿下整体脊柱骨盆排列的研究较少，因此评估坐姿相关的变化对于未来座椅设计的发展和脊柱排列的适当恢复非常重要。
本研究旨在测量人坐在汽车座椅时整体脊柱排列的变化，并分析这些变化的特征。
这是一项关于整体脊柱排列变化的放射学评估的前瞻性协作研究。
该研究纳入了 113 名无症状成年参与者（56 名男性和 57 名女性），无脊柱疾病或下肢手术史，且目前无下腰痛或下肢痛。
通过测量各种角度评估影像学结果：颈椎前凸（CL）、胸椎后凸（TK）、胸腰椎后凸（TLK）、腰椎前凸（LL）、骶骨倾斜角（SS）、骨盆倾斜角（PT）、骨盆入射角（PI）、C7 矢状垂直轴（C7-SVA）、T1 骨盆倾斜角（T1SPI）和 T1 骨盆角（TPA）。
在站立和坐姿下拍摄 X 线片。统计分析的目标变量为站立位时测量的脊柱排列（CL、TK、TLK、LL、C7-SVA、T1SPI、TPA、SS、PT 和 PI）、坐姿时测量的身体排列（CL、TK、TLK、LL、C7-SVA、T1SPI、TPA、SS 和 PT）以及站立位到坐姿位的变化（∆CL、∆TK、∆TLK、∆LL、∆C7-SVA、∆T1SPI、∆TPA、∆SS 和 ∆PT）。解释变量为性别、年龄、身高和体重指数。
从站立位变为坐姿位时，CL 平均减少 5.3°，TK 平均减少 1.3°，TLK 平均增加 6.8°，LL 平均减少 35°，SS 平均减少 49.2°，PT 平均增加 49.2°，C7-SVA 向后移动平均 106.7mm，T1SPI 平均减少 18.8°，TPA 平均增加 21.1°。统计分析显示，老年参与者的 LL 明显减少。在站立位到坐姿位的变化后，高个子参与者的 ∆TLK 和 ∆TPA 明显增加，而高个子参与者的 ∆T1SPI 明显减少。
除其他变化外，人坐在汽车座椅时，脊柱排列最明显的变化是 LL 减少和骨盆倾斜增加。然而，这些脊柱排列的变化随年龄和身高而不同。这些发现可能有助于未来座椅设计的发展和脊柱排列的适当手术恢复。
