Department of Orthopaedic Surgery, Ibi Kousei Hospital, Gifu, Japan.
Spine (Phila Pa 1976). 2010 Apr 20;35(9):995-1001. doi: 10.1097/BRS.0b013e3181bb8188.
A study was performed using an axial loading device in healthy young subjects.
To determine whether sagittal alignment during axial loading using a compression device can accurately simulate the standing posture.
Axial compression devices are widely used for simulation of standing position during magnetic resonance imaging (MRI) or computed tomography (CT) scans. However, images taken during axial loading have not been compared with those obtained in a standing posture.
The study population comprised 14 asymptomatic healthy volunteers (7 men and 7 women: age 21-32, mean 27 years). Lumbar lateral radiograph films obtained in the standing posture (standing condition), lumbar CT images with axial loading using a DynaWell compression device (axial loading condition), and CT images without loading (control) were compared. Changes in spinal length, lumbar disc height, segmental lordotic angle, and total lumbar lordotic angle were compared among the conditions.
Spinal length was significantly decreased in both the axial loading and standing conditions compared with controls. The magnitude of the changes was greater in the standing condition than in the axial loading condition. Segmental lordotic angle at L2/3 and L3/4 was significantly increased in both axial loading and standing conditions. However, disc lordotic angle at L5/S was significantly decreased in the axial loading condition, while the standing condition showed no significant change. Consequently, the pelvic angle showed a significant decrease in the axial loading condition.
The compression device simulates the lumbar segmental alignment change from supine to standing posture in L1/2, L2/3, L3/4, and L4/5. However, in L5/S, axial loading using the DynaWell altered lumbar segmental alignment with a kyphotic change, while no significant difference was observed in this level between standing and supine positions. Awareness of these phenomena are essential for accurate interpretation of imaging results.
本研究在健康年轻受试者中使用轴向加载装置进行。
确定使用压缩装置进行轴向加载时矢状位对线是否可以准确模拟站立姿势。
轴向压缩装置广泛用于模拟磁共振成像（MRI）或计算机断层扫描（CT）扫描时的站立位置。然而，尚未将轴向加载期间拍摄的图像与站立位获得的图像进行比较。
研究对象包括 14 名无症状健康志愿者（7 名男性和 7 名女性；年龄 21-32 岁，平均 27 岁）。比较站立位获得的腰椎侧位射线照片（站立位）、使用 Dynawell 压缩装置进行轴向加载时的腰椎 CT 图像（轴向加载位）和无加载时的 CT 图像（对照组）。比较各组之间脊柱长度、腰椎间盘高度、节段前凸角和总腰椎前凸角的变化。
与对照组相比，轴向加载位和站立位的脊柱长度均显著缩短。站立位的变化幅度大于轴向加载位。L2/3 和 L3/4 的节段前凸角在轴向加载位和站立位均显著增加。然而，L5/S 的椎间盘前凸角在轴向加载位显著降低，而站立位没有明显变化。因此，轴向加载位骨盆角显著减小。
压缩装置可模拟 L1/2、L2/3、L3/4 和 L4/5 从仰卧位到站立位的腰椎节段对线变化。然而，在 L5/S 水平，Dynawell 的轴向加载改变了腰椎节段对线，呈后凸变化，而站立位与仰卧位之间无显著差异。了解这些现象对于准确解释影像学结果至关重要。
