Upasani Vidyadhar V, Chambers Reid C, Dalal Ali H, Shah Suken A, Lehman Ronald A, Newton Peter O
Rady Children's Hospital and Health Center, San Diego, CA, USA.
Spine (Phila Pa 1976). 2009 Aug 1;34(17):1855-62. doi: 10.1097/BRS.0b013e3181abf797.
Bench-top and retrospective analysis to assess vertebral rotation based on the appearance of bilateral pedicle screws in patients with adolescent idiopathic scoliosis (AIS).
To develop a clinically relevant radiographic grading system for evaluating postoperative thoracic apical vertebral rotation that would correlate with computed tomography (CT) measures of rotation.
The 3-column vertebral body control provided by bilateral pedicle screws has enabled scoliosis surgeons to develop advanced techniques of direct vertebral derotation. Our ability to accurately quantify spinal deformity in the axial plane, however, continues to be limited.
Trigonometry was used to define the relationship between the position of bilateral pedicle screws and vertebral rotation. This relationship was validated using digital photographs of a bench-top model. The mathematical relationships were then used to calculate vertebral rotation from standing postoperative, posteroanterior radiographs in AIS patients and correlated with postoperative CT measures of rotation.
Fourteen digital photographs of the bench-top model were independently analyzed twice by 3 coauthors. The mathematically calculated degree of rotation was found to correlate significantly with the actual degree of rotation (r = 0.99; P < 0.001) and the intra- and interobserver reliability for these measurements were both excellent (kappa = 0.98 and kappa = 0.97, respectively). In the retrospective analysis of 17 AIS patients, the average absolute difference between the radiographic measurement of rotation and the CT measure was only 1.9 degrees +/- 2.0 degrees (r = 0.92; P < 0.001). Based on these correlations a simple radiographic grading system for postoperative apical vertebral rotation was developed.
An accurate assessment of vertebral rotation can be performed radiographically, using screw lengths and screw tip-to-rod distances of bilateral segmental pedicle screws and a trigonometric calculation. These data support the use of a simple radiographic grading system to approximate apical vertebral rotation in AIS patients treated with bilateral apical pedicle screws.
基于青少年特发性脊柱侧凸（AIS）患者双侧椎弓根螺钉的表现进行台式及回顾性分析，以评估椎体旋转情况。
建立一种临床相关的影像学分级系统，用于评估术后胸椎顶椎旋转情况，并使其与计算机断层扫描（CT）旋转测量结果相关联。
双侧椎弓根螺钉提供的三柱椎体控制使脊柱侧凸外科医生能够开发直接椎体去旋转的先进技术。然而，我们在轴向平面准确量化脊柱畸形的能力仍然有限。
运用三角学定义双侧椎弓根螺钉位置与椎体旋转之间的关系。通过台式模型的数码照片对这种关系进行验证。然后利用这些数学关系，根据AIS患者术后站立位正位X线片计算椎体旋转，并与术后CT旋转测量结果进行关联。
3位共同作者对台式模型的14张数码照片进行了两次独立分析。发现数学计算的旋转度数与实际旋转度数显著相关（r = 0.99；P < 0.001），这些测量的观察者内及观察者间可靠性均极佳（kappa分别为0.98和0.97）。在对17例AIS患者的回顾性分析中，旋转的X线测量值与CT测量值之间的平均绝对差值仅为1.9°±2.0°（r = 0.92；P < 0.001）。基于这些相关性，开发了一种用于术后顶椎旋转的简单影像学分级系统。
使用双侧节段性椎弓根螺钉的螺钉长度和螺钉尖端至棒的距离以及三角学计算，可以通过X线片准确评估椎体旋转。这些数据支持使用一种简单的影像学分级系统来估算接受双侧顶椎椎弓根螺钉治疗的AIS患者的顶椎旋转情况。
