三维CT测量在骶髂关节个体化置钉中的应用

背景：骶髂螺钉直接固定复位后的骶髂关节，可提供足够的骨盆稳定性，其生物力学稳定性优于其他常用的内固定。 目的：探讨三维CT测量在骶髂关节个体化置钉中的应用，为临床个体化置钉提供影像解剖学的依据。 设计、时间及地点：测量实验，于2008-01/07在河北工程大学CT中心及解剖实验室完成。 材料：成人骶髂关节标本8例，男女年龄不限，无脊柱疾病，由河北工程大学医学院解剖教研室提供，体积分数为0.1的甲醛处理。 方法：每例标本的S1均经螺旋CT断层扫描后，图像输入到计算机软件，对图像进行处理，测量S1椎弓根骶髂关节的钉道直径，骶髂关节于髂骨后外侧面的进针点，骶髂关节螺钉的长度及进针方向，并根据数据模拟出各椎弓根的形态特点，依测量的数据和角度在标本上置钉，再行CT扫描观察螺钉在椎弓根内的位置。 主要观察指标：骶髂关节螺钉参数的数值，置钉后椎弓根钉的在位率。 结果：S1椎弓根宽为(24.6±2.7) mm，高为(19.1±2.9) mm，进针点至对侧前皮质的距离为(87.1±3.2) mm，进针方向与冠状面的夹角为(24.9±1.5)°，与矢状面夹角为(21.2±1.6)°，进针点与骼后上棘的距离为(37.5±2.6) mm，与骼后下棘的距离为(38.5±2.7) mm；与坐骨大切迹的距离为(43.2±4.6) mm，双侧16次穿钉，15枚骶髂关节螺钉完全在位。 结论：利用三维CT测量的数据辅助，严格按照个体化椎弓根的轴线方向置钉，置钉的成功率较高。

Application of three-dimensional CT measurement in individual screw insertion into the sacroiliac joint

BACKGROUND: Iliosacral screw fixing the sacroiliac joint after reduction can provide the stability of the pelvis. Its biological stability is better than other internal fixation. OBJECTIVE: To observe the role of spinal CT measurement in the transpedicular screw fixation in the sacroiliac joint so as to provide related morphological data for the application of iliosacral screw fixation in sacroiliac joint disruption. DESIGN, TIME AND SETTING: Measurement experiment was performed at the CT center and anatomy laboratory of Hebei University of Engineering from January to July 2008. MATERIALS: Eight specimens of adult sacroiliac joint, irrespective of gender, with no spinal diseases, were provided by anatomy laboratory of Hebei University of Engineering, treated by 0.1 volume fraction formaldehyde. METHODS: S1 of each specimen underwent spiral CT scanning, and the images were input in computer, and diameter of the pedicle S1, entrance point, length of screw and entrance direction were measured. Topography of S1 vertebral arch was simulated. The screws were inserted according to the data and angles, and the accuracy of placement was assessed by postoperative CT scanning. MAIN OUTCOME MEASURES: Liner parameters of pedicle and accuracy of placement. RESULTS: The width and height of the pedicle S1 was (24.6±2.7) mm and (19.1±2.9) mm. The distance from entrance point to contrary anterior cortex of S1 vertebral body was (87.1±3.2) mm; the direction of screw was (24.9±1.5)° to the coronal plane, and (21.2±1.6)°to the horizontal plane. The optimal entrance point on posterolateral iliac ala for screw fixation was (38.5±2.7) mm anterior to posterior superior iliac spine, (37.5±2.6) mm anterior to posterior inferior iliac spine, and (43.2±4.6) mm superior to the greater sciatic notch. Sixteen pedicles were instrumented, and 15 cases (93.75%) were entirely within the pedicle. CONCLUSION: The insertion of pedicle screw is safe on the basis of three-dimensional CT measurement, while transpedicular screw fixation must be strictly operated according to the axis of the pedicle.