骶髂关节螺钉固定的钉道参数应用解剖学研究

Applied anatomic study of the parameters of screw fixation for the sacroiliac joint

目的 :为经S1椎弓根水平骶髂关节螺钉固定提供解剖学依据。方法 :对 2 2例骨盆标本进行研究 ,测量S1椎弓根宽和高 ,骶髂螺钉的进针点和进针方向 ,进针点至S1椎体对侧前皮质距离。确定进针点后 ,以 5具新鲜尸体对进针方法进行验证。结果 :S1椎弓根宽和高分别为 (2 7.7± 1.9)mm和 (2 0 .2± 2 .3 )mm ;螺钉进针点位于髂后下棘前方 (2 4.6± 2 .9)mm ,坐骨大切迹上方 (4 1.8± 3 .4)mm ;进针方向为垂直于髂骨翼后外侧面 ,然后向后侧倾斜 (7.7± 3 .8)° ,向尾端倾斜 (7.1± 2 .3 )° ;进针点至S1椎体对侧前皮质距离为 (86.5± 3 .8)mm。以此进针方法行 10枚螺钉固定 ,无螺钉穿出椎弓根。结论 :髂后下棘和坐骨大切迹恒定存在 ,变异小 ;螺钉进针点位于髂后下棘前方 2 5mm ,坐骨大切迹上方 40mm ;螺钉长 75mm ;进针方向为垂直于髂骨翼后外侧面 ,然后向后侧倾斜 5°～ 10° ,向尾端倾斜 5°～ 10°。

Objective: To provide anatomic basis for iliosacral screw fixation at the level of the pedicle of the first sacral vertebra (S_1), the present study was carried out. Methods: 22 pelvis specimens of native adults were studied, a total of 44 sacroiliac joint anthropometric measurement were performed on 22 cadaveric pelvises to determine the shape of S_1 pedicle transverse section, the optimal entry point for iliosacral screw on the outer table of the posterolateral ilium, the direction of screw, and the distance from entry point to contrary anterior cortex of S_1 vertebral body. After confirming the optimal entry point, verify the different methods for inserting iliosacral screw on 5 fresh pelvises specimens. Results: The shape of S_2 pedicle transverse section was almost ellipse. The broad and height of the pedicle of S_1 were 27.7±1.9 mm and 20.2±2.3 mm, respectively. The optimal entry point on the posterolateral ilium for screw fixation was found to exist 24.6±2.9 mm anterior to posterior inferior iliac spine and 41.8±3.4 mm superior to the greater sciatic notch. The distance from entry point to contrary anterior cortex of S_1 vertebral body was 86.5±3.8 mm.The direction of screw was perpendicular to the outer table of the posterolateral ilium, then 7.7°±3.8° in posterior oblique and 7.1°±2.3° in cauda oblique. The result of iliosacral screw fixation according to the entry point measured in this study was that no screw penetrate pedicle of S_1 or sacral vertebral body. The result of iliosacral screw fixation according to posterior gluteal line was that two of seven lag screws penetrate pedicle of S_1. The result of iliosacral screw fixation according to posterior inferior iliac spine was that four of ten screws penetrate pedicle of S_1 or sacral vertebral body. Conclusion: The posterior inferior iliac spine and the sciatic notch constant exist, they are easily exposed and identified in operation. The entry point was located 25mm anterior to posterior inferior iliac spine and 40mm superior to the greater sciatic notch. The length of iliosacral screw was 75 mm. The direction of screw was perpendicular to the outer table of the posterolateral ilium, then 5°～10° in posterior oblique and 5°～10° in cauda oblique.