Davis Colin M, Grant Caroline A, Pearcy Mark J, Askin Geoffrey N, Labrom Robert D, Izatt Maree T, Adam Clayton J, Little J Paige
Paediatric Spine Research Group, Institute of Health and Biomedical Innovation at Centre for Children's Health Research, Queensland University of Technology, Brisbane, Australia.
Mater Health Services, South Brisbane, Australia.
Clin Orthop Relat Res. 2017 Mar;475(3):884-893. doi: 10.1007/s11999-016-5188-2. Epub 2016 Nov 29.
Adolescent idiopathic scoliosis is a complex three-dimensional deformity of the spine characterized by deformities in the sagittal, coronal, and axial planes. Spinal fusion using pedicle screw instrumentation is a widely used method for surgical correction in severe (coronal deformity, Cobb angle > 45°) adolescent idiopathic scoliosis curves. Understanding the anatomic difference in the pedicles of patients with adolescent idiopathic scoliosis is essential to reduce the risk of neurovascular or visceral injury through pedicle screw misplacement.
QUESTIONS/PURPOSES: To use CT scans (1) to analyze pedicle anatomy in the adolescent thoracic scoliotic spine comparing concave and convex pedicles and (2) to assess the intra- and interobserver reliability of these measurements to provide critical information to spine surgeons regarding size, length, and angle of projection.
Between 2007 and 2009, 27 patients with adolescent idiopathic scoliosis underwent thoracoscopic anterior correction surgery by two experienced spinal surgeons. Preoperatively, each patient underwent a CT scan as was their standard of care at that time. Twenty-two patients (mean age, 15.7 years; SD, 2.4 years; range, 11.6-22 years) (mean Cobb angle, 53°; SD, 5.3°; range, 42°-63°) were selected. Inclusion criteria were a clinical diagnosis of adolescent idiopathic scoliosis, female, and Lenke type 1 adolescent idiopathic scoliosis with the major curve confined to the thoracic spine. Using three-dimensional image analysis software, the pedicle width, inner cortical pedicle width, pedicle height, inner cortical pedicle height, pedicle length, chord length, transverse pedicle angle, and sagittal pedicle angles were measured. Randomly selected scans were remeasured by two of the authors and the reproducibility of the measurement definitions was validated through limit of agreement analysis.
The concave pedicle widths were smaller compared with the convex pedicle widths at T7, T8, and T9 by 37% (3.44 mm ± 1.16 mm vs 4.72 mm ± 1.02 mm; p < 0.001; mean difference, 1.27 mm; 95% CI, 0.92 mm-1.62 mm), 32% (3.66 mm ± 1.00 mm vs 4.82 mm ± 1.10 mm; p < 0.001; mean difference, 1.16 mm; 95% CI, 0.84 mm-1.49 mm), and 25% (4.10 mm ± 1.57 mm vs 5.12 mm ± 1.17 mm; p < 0.001; mean difference, 1.02 mm; 95% CI, 0.66 mm-1.39 mm), respectively. The concave pedicle heights were smaller than the convex at T5 (9.43 mm ± 0.98 vs 10.63 mm ± 1.10 mm; p = 0.002; mean difference, 1.02 mm; 95% CI, 0.59 mm-1.45 mm), T6 (8.87 mm ± 1.37 mm vs 10.88 mm ± 0.81 mm; p < 0.001; mean difference, 2.02 mm; 95% CI, 1.40 mm-2.63 mm), T7 (9.09 mm ± 1.24 mm vs 11.35 mm ± 0.84 mm; p < 0.001; mean difference, 2.26 mm; 95% CI, 1.81 mm-2.72 mm), and T8 (10.11 mm ± 1.05 mm vs 11.86 mm ± 0.88 mm; p < 0.001; mean difference, 1.75 mm; 95% CI, 1.30 mm-2.19 mm). Conversely, the concave transverse pedicle angle was larger than the convex at levels T6 (11.37° ± 4.48° vs 8.82° ± 4.31°; p = 0.004; mean difference, 2.54°; 95% CI, 1.10°-3.99°), T7 (12.69° ± 5.93° vs 8.65° ± 3.79°; p = 0.002; mean difference, 4.04°; 95% CI, 1.90°-6.17°), T8 (13.24° ± 5.28° vs 7.66° ± 4.87°; p < 0.001; mean difference, 5.58°; 95% CI, 2.99°-8.17°), and T9 (19.95° ± 5.69° vs 8.21° ± 4.02°; p < 0.001; mean difference, 4.74°; 95% CI, 2.68°-6.80°), indicating a more posterolateral to anteromedial pedicle orientation.
There is clinically important asymmetry in the morphologic features of pedicles in individuals with adolescent idiopathic scoliosis. The concave side of the curve compared with the convex side is smaller in height and width periapically. Furthermore, the trajectory of the pedicle is more acute on the convex side of the curve compared with the concave side around the apex of the curve. Knowledge of these anatomic variations is essential when performing scoliosis correction surgery to assist with selecting the correct pedicle screw size and trajectory of insertion to reduce the risk of pedicle wall perforation and neurovascular injury.
青少年特发性脊柱侧凸是一种复杂的脊柱三维畸形，其特征在于矢状面、冠状面和轴面的畸形。使用椎弓根螺钉器械进行脊柱融合术是治疗严重（冠状面畸形，Cobb角>45°）青少年特发性脊柱侧凸曲线的一种广泛应用的手术矫正方法。了解青少年特发性脊柱侧凸患者椎弓根的解剖差异对于降低因椎弓根螺钉误置导致神经血管或内脏损伤的风险至关重要。
问题/目的：使用CT扫描（1）分析青少年胸椎脊柱侧凸患者的椎弓根解剖结构，比较凹侧和凸侧椎弓根；（2）评估这些测量的观察者内和观察者间可靠性，为脊柱外科医生提供有关尺寸、长度和投影角度的关键信息。
2007年至2009年期间，27例青少年特发性脊柱侧凸患者接受了由两位经验丰富的脊柱外科医生进行的胸腔镜前路矫正手术。术前，每位患者按照当时的标准护理流程进行了CT扫描。选择了22例患者（平均年龄15.7岁；标准差2.4岁；范围11.6 - 22岁）（平均Cobb角53°；标准差5.3°；范围42° - 63°）。纳入标准为青少年特发性脊柱侧凸的临床诊断、女性以及Lenke 1型青少年特发性脊柱侧凸且主要曲线局限于胸椎。使用三维图像分析软件，测量椎弓根宽度、椎弓根内侧皮质宽度、椎弓根高度、椎弓根内侧皮质高度、椎弓根长度、弦长、椎弓根横向角度和椎弓根矢状角度。两位作者对随机选择的扫描进行了重新测量，并通过一致性界限分析验证了测量定义的可重复性。
在T7、T各节段，凹侧椎弓根宽度比凸侧分别小37%（3.44 mm ± 1.16 mm对4.72 mm ± 1.02 mm；p < 0.001；平均差异1.27 mm；95%可信区间，0.92 mm - 1.62 mm）、32%（3.66 mm ± 1.00 mm对4.82 mm ± 1.10 mm；p < 0.001；平均差异1.16 mm；95%可信区间，0.84 mm - 1.49 mm）和25%（4.10 mm ± 1.57 mm对5.12 mm ± 1.17 mm；p < 0.001；平均差异1.02 mm；95%可信区间，0.66 mm - 1.39 mm）。在T5（9.43 mm ± 0.98对10.63 mm ± 1.10 mm；p = 0.002；平均差异1.02 mm；95%可信区间，0.59 mm - 1.45 mm）、T6（8.87 mm ± 1.37 mm对10.88 mm ± 0.81 mm；p < 0.001；平均差异2.02 mm；95%可信区间，1.40 mm - 2.63 mm）、T7（9.09 mm ± 1.24 mm对11.35 mm ± 0.84 mm；p < 0.001；平均差异2.26 mm；95%可信区间，1.81 mm - 2.72 mm）和T8（10.11 mm ± 1.05 mm对11.86 mm ± 0.88 mm；p < 0.001；平均差异1.75 mm；95%可信区间，1.30 mm - 2.19 mm），凹侧椎弓根高度小于凸侧。相反，在T6（11.37° ± 4.48°对8.82° ± 4.31°；p = 0.004；平均差异2.54°；95%可信区间，1.10° - 3.99°）、T7（12.69° ± 5.93°对8.65° ± 3.79°；p = 0.002；平均差异4.04°；95%可信区间，1.90° - 6.17°）、T8（13.24° ± 5.28°对7.66° ± 4.87°；p < 0.001；平均差异5.58°；95%可信区间，2.99° - 8.17°）和T9（19.95° ± 5.69°对8.21° ± 4.02°；p < 0.001；平均差异4.74°；95%可信区间，2.68° - 6.80°）节段，凹侧椎弓根横向角度大于凸侧，表明椎弓根方向从后外侧到前内侧更为明显。
青少年特发性脊柱侧凸患者椎弓根的形态特征存在临床上重要的不对称性。与凸侧相比，曲线凹侧的根尖周围高度和宽度较小。此外，与曲线凹侧相比，曲线凸侧在曲线顶点周围的椎弓根轨迹更陡。在进行脊柱侧凸矫正手术时，了解这些解剖变异对于选择正确的椎弓根螺钉尺寸和插入轨迹以降低椎弓根壁穿孔和神经血管损伤的风险至关重要
