Department of Spine Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road 321, Nanjing, China.
Eur Spine J. 2012 Oct;21(10):2043-9. doi: 10.1007/s00586-012-2315-y. Epub 2012 Apr 20.
To compare the positions of the aorta relative to vertebral bodies and the potential risk of the aorta impingement for pedicle screw (PS) placement between right-sided and left-sided thoracolumbar/lumbar curves of adolescent idiopathic scoliosis (AIS).
Thirty-nine AIS patients with a main thoracolumbar or lumbar curve were recruited. The Lenke's classification was type 5C in all patients. According to the convexity of the thoracolumbar or lumbar curves, the patients were divided into either group R or Group L. The patients in Group R had a main right-sided thoracolumbar/lumbar curve, and the patients in Group L had a main left-sided thoracolumbar/lumbar curve. Axial CT images from T12 to L4 at the midvertebral body level were obtained to evaluate Aorta-vertebra angle (α), Vertebral rotation angle (β), Lefty safety distance (LSD), and Right safety distance (RSD). The risks of the aorta impingement from T12 to L4 were calculated and then compared between the two groups.
The α increased from T12 through L4 in Group R, increased from T12 through L1, and then decreased from L1 through L4 in Group L. The β decreased from T12 through L4 in both groups. The LSD constantly increased from T12 through L4 in Group R, increased from T12 through L3, and then decreased from L3 through L4 in Group L. The RSD increased from T12 through L3 and then decreased from L3 through L4 in both groups. With the increment of the lengths of the simulated screws, the aorta impingement risks were constantly elevated at all levels in both groups. The aorta was at a high risk of impingement from left PS regardless of the diameters of the simulated screws in Group R (80-100 % at T12 and 53.3-100 % at L1). In Group L, the aorta was completely safe when using 35 mm (0 at all levels) PS and at high risks of the aorta impingement on the right side from 45 mm PSs (31.8-72.7 %). In all, the risks of the aorta impingement were mainly from left PS in Group R and from right PS in Group L, and the risk of the aorta impingement from PS placement was generally higher in right thoracolumbar or lumbar curves when compared with that of the left.
The present study illustrated different changed positions of the aorta relative to vertebrae between thoracolumbar/lumbar curves with different convexities. In right-sided curve, the risks of the aorta impingement were mainly from left PS while in left-sided curves, from right PS. The aorta was more proximal to entry points in right-sided lumbar curve when compared with left-sided curve; thus placing PS carries more risks in right-sided thoracolumbar/lumbar curve. Surgeons should be more cautious when placing PSs on the concave sides of T12 and L1 vertebrae of right-sided thoracolumbar/lumbar curves.
比较青少年特发性脊柱侧凸（AIS）右侧和左侧胸腰椎/腰椎曲线中主动脉相对于椎体的位置以及主动脉撞击的潜在风险，以进行椎弓根螺钉（PS）放置。
招募了 39 例主胸腰椎或腰椎曲线的 AIS 患者。所有患者的 Lenke 分类均为 5C 型。根据胸腰椎或腰椎曲线的凸度，将患者分为 R 组或 L 组。R 组患者的主胸腰椎/腰椎曲线为右侧，L 组患者的主胸腰椎/腰椎曲线为左侧。在 T12 到 L4 椎体的中矢状面获得轴向 CT 图像，以评估主动脉-椎体角（α）、椎体旋转角（β）、左侧安全距离（LSD）和右侧安全距离（RSD）。计算 T12 到 L4 段主动脉撞击的风险，并在两组之间进行比较。
R 组中α从 T12 到 L4 逐渐增加，从 T12 到 L1 增加，然后从 L1 到 L4 减少。β在两组中均从 T12 到 L4 减少。R 组中 LSD 从 T12 到 L4 持续增加，从 T12 到 L3 增加，然后从 L3 到 L4 减少。RSD 在两组中从 T12 到 L3 增加，然后从 L3 到 L4 减少。随着模拟螺钉长度的增加，两组在所有水平的主动脉撞击风险均持续升高。在 R 组中，无论模拟螺钉的直径如何，左侧 PS 都存在主动脉撞击的高风险（T12 为 80-100%，L1 为 53.3-100%）。在 L 组中，使用 35mm（所有水平均为 0）PS 时，主动脉完全安全，而使用 45mm PS 时，右侧主动脉撞击的风险较高（31.8-72.7%）。总体而言，在 R 组中，主动脉撞击的风险主要来自左侧 PS，而在 L 组中，来自右侧 PS，与左侧相比，右侧胸腰椎或腰椎曲线中 PS 放置的主动脉撞击风险通常更高。
本研究表明，不同凸度的胸腰椎/腰椎曲线中主动脉相对于椎体的位置存在不同的变化。在右侧曲线上，主动脉撞击的风险主要来自左侧 PS，而在左侧曲线上，来自右侧 PS。右侧腰椎曲线上主动脉更靠近进入点，因此右侧胸腰椎/腰椎曲线上 PS 放置的风险更高。外科医生在放置 T12 和 L1 椎体凹侧的 PS 时应更加小心。
