Abul-Kasim Kasim, Strömbeck Anita, Ohlin Acke, Maly Pavel, Sundgren Pia C
Department of Radiology, Section of Neuroradiology, University of Lund, Malmö University Hospital, Malmo, Sweden. Kasim.Abul-
Spine (Phila Pa 1976). 2009 Apr 20;34(9):941-8. doi: 10.1097/BRS.0b013e31819b22a4.
A retrospective study.
To evaluate the reliability of computed tomography (CT) with low radiation dose in the assessment of implant status in patients with adolescent idiopathic scoliosis (AIS).
The use of all-pedicle screw construct in scoliosis corrective surgery continues to gain increasing popularity since their introduction 1994 although their use in the thoracic spine carries a potential risk for neurovascular complications. CT is the method widely used to evaluate screw placement.
Retrospective analysis of 46 consecutive low-dose spine CT in patients with AIS after posterior corrective surgery. Status of 809 titanium screws (642 thoracic) was evaluated. The degree of interobserver and intraobserver agreements about implant status was used as an indicator of the reliability of the low-dose spine CT in the assessment of accuracy of pedicle screw insertion. A new grading system has been developed for this purpose. Five types of misplacement have been evaluated: lateral, medial, and anterior cortical perforations; endplate perforation; and foraminal perforation.
The analysis has shown a substantial interobserver and intraobserver agreements (kappa: 0.69 and 0.76, respectively) in differentiating pedicle screws with acceptable placement from screws with partial or total cortical perforation. None of the examinations was subjectively classified as unreliable.
The study has shown that low-dose spine CT is a reliable method in evaluating screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the here proposed grading system. The new grading system of screw misplacement was feasible and in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. The reliability of low-dose spine CT in evaluation of lateral and medial cortical perforations was substantial. To reduce the radiation load, the postoperative assessment of titanium implants should be performed with low-dose CT.
一项回顾性研究。
评估低辐射剂量计算机断层扫描（CT）在评估青少年特发性脊柱侧凸（AIS）患者植入物状态方面的可靠性。
自1994年全椎弓根螺钉结构被引入脊柱侧弯矫正手术以来，其应用越来越广泛，尽管在胸椎使用时存在神经血管并发症的潜在风险。CT是广泛用于评估螺钉置入情况的方法。
对46例AIS患者后路矫正手术后连续进行的低剂量脊柱CT进行回顾性分析。评估了809枚钛螺钉（642枚胸椎螺钉）的情况。观察者间和观察者内对植入物状态的一致性程度被用作低剂量脊柱CT评估椎弓根螺钉置入准确性可靠性的指标。为此开发了一种新的分级系统。评估了五种类型的错位：外侧、内侧和前方皮质穿孔；终板穿孔；以及椎间孔穿孔。
分析显示，在区分置入位置可接受的椎弓根螺钉与部分或完全皮质穿孔的螺钉方面，观察者间和观察者内具有高度一致性（kappa值分别为0.69和0.76）。没有一项检查被主观判定为不可靠。
本研究表明，使用本文提出的分级系统，低剂量脊柱CT是评估AIS患者后路脊柱侧弯手术后钛植入物螺钉置入情况的可靠方法。新的螺钉错位分级系统是可行的，并且与关于轻微椎弓根侵犯错位无害性的普遍共识一致。低剂量脊柱CT在评估外侧和内侧皮质穿孔方面的可靠性很高。为了减少辐射负荷，钛植入物的术后评估应采用低剂量CT进行。
