骶髂关节经皮拉力螺钉固定钉道参数的解剖学测量

目的 为经S_1椎弓根水平骶髂关节拉力螺钉固定术提供应用解剖学依据.方法 2008年6月至2009年7月收集50个成人骨盆的螺旋CT扫描数据,重建骨盆三维模型,模拟经皮托力螺钉固定.测量S_1椎弓根的宽和高、骶髂关节拉力螺钉的进针点和进针方向、进针点至S_1椎体对侧前皮质和髂后上棘的距离.结果 S_1椎弓根的宽和高分别为(20.43±1.63)mm和(20.26±0.99)mm;2枚螺钉的进针点均在髂前上棘和髂后上棘的连线上方,至髂后上棘的距离分别为(49.87±6.80)mm和(51.11±7.15)mm.螺钉平行进入S_1椎弓根,与髂骨翼后外侧面垂直,与冠状面和欠状面的夹角分别为18.35°±5.20°和77.62°±3.98°.进针点到S1椎体对侧前皮质的距离分别为(76.08±4.32)mm和(77.62±3.98)mm.骶髂关节拉力螺钉的长度、S_1椎弓根的高度和宽度、进针点到髂后上棘的距离、进针点与冠状面的夹角在男女之间差异有统计学意义(P<0.05).结论 正常成人在S_1椎弓根水平均町置入2枚直径为6.5 mm的拉力螺钉,钉道参数的解剖学测量为骶髂关节拉力螺钉固定手术导航模板的设计提供了理论基础.

Anatomical parameters for percutaneous lag screw fixation of the sacroiliac joint

Objective To provide anatomic evidence for iliosacral screw fixation at the pedicle level of the first sacral vertebra(S1).Methods Virtual three-dimensional models were reconstructed on the basis of computed tomography(CT)scans obtained from 50 adult patients without any bony problem.The percutaneous lag screw fixation of the sacroiliac joint was simulated.The width and height of the S1 pedicle,the optimal entry points for iliosacral screws on the outer posterolateral ilium,the directions of screws,and the distances from the entry point to the contrary anterior cortex of the S1 vertebral body and to the posterior superior lilac spine were measured.Results The width and height of the S1 pedicle were(20.43 ±1.63)mm and(20.26±0.99)mm,respectively.The optimal entry points of the 2 iliosacral screws were on both above the line between the anterior superior iliac spine and the posterior superior iliac spine.The distances to the posterior superior lilac spine were(49.87 ± 6.80)mm and(51.11 ± 7.15)mm,respectively.Iliosacral screws got into the S1 pedicle in parallel,perpendicular to the outer posterolateral ilium,with 18.35°± 5.20°to the coronal plane and 77.62°± 3.98° to the sagittal plane.The distances from the entry points of 2 iliosacral screws to the contrary anterior cortex of S1 vertebral body were(76.08 ± 4.32)mm and(77.62 ± 3.98)mm,respectively.Differences in length,the width and height of the S1 pedicle,distance to the posterior superior iliac spine and angle to the coronal plane of the iliosacral screws between men and women were of statistical significance(P <0.05).Conclusions Two iliosacral screws of 6.5 mm in diameter can be implanted at the level of the first sacral vertebra in healthy adults.The anatomic parameters measured can be applied in design of the surgical navigation template for percutaneous lag screw fixation of the sacroiliac joint.