髋臼前柱螺钉固定解剖学研究及导向器的设计

目的为经髋臼前柱螺钉固定提供解剖学依据。方法对22只成人尸体骨盆标本,共44侧髋臼进行解剖学研究,观测髋臼前柱横断面形状,测量髋臼前柱螺钉固定在髂骨翼外侧面的进针点、进针方向、钉道直径、进针点至闭孔沟的距离。结果髋臼前柱横断面呈近似直角三角形,钉道直径10.5±0.8mm;螺钉进针点位于髂骨翼后外侧面坐骨大切迹和髂前上棘连线上方9.2±2.4mm,距坐骨大切迹38.5±3.8mm;螺钉进针方向于水平面与中心线夹角为40.7±3.8°,矢状面向尾端成角54.2±5.5°。钉道长度84.1±6.2mm。并设计出髋臼前柱螺钉固定导向器。结论髋臼前柱可接受1枚直径6.5mm、长70mm的螺钉,螺钉进针点位于髂骨翼后外侧面坐骨大切迹和髂前上棘连线上方10mm,距坐骨大切迹40mm。螺钉进针方向于水平面与中心线夹角40°,矢状面向尾端成角55°。髋臼前柱螺钉固定导向器将提高前柱螺钉固定的安全性。

AN ANATOMIC STUDY OF LAG SCREW PLACEMENT IN ANTERIOR COLUMN OF ACETABULUM AND DESIGN OF TARGETING DEVICE

OBJECTIVE: To provide the anatomic basis for the lag screw placement in the anterior column of the acetabulum. METHODS: Twenty-two pelvis specimens with 44 acetabula of the native adult cadavers were studied. The anthropometric measurement was performed on 44 acetabula to determine the shape of the transverse section of the anterior column of the acetabulum, the optimal entry point for the lag screw on the outer table of the ilium, the direction of the screw, and the distance from the entry point to the obturator groove. RESULTS: The transverse section of the anterior column of the acetabulum was almost triangle-shaped. The path for the lag screw placement was 10.5 +/- 0.8 mm in diameter. The optimal entry point on the posterolateral ilium for the screw fixation was found to exist 9.2 +/- 2.4 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 38.5 +/- 3.8 mm superior to the greater sciatic notch. The distance from the entry point to the obturator groove was 84.1 +/- 6.2 mm. The inclination of the lag screw was 54.2 +/- 5.5 degrees at the caudal direction in the sagittal plane and 40.7 +/- 3.8 degrees in the horizontal plane. The device for the safe screw placement in the anterior column was designed. CONCLUSION: The above data can facilitate an insertion of one 6.5 mm lag screw into the anterior acetabular column and minimize the risk of articular violation or cortical penetration, which has a narrow margin of safety. The safe length of the lag screw should be 70 mm. The optimal entry point on the posterolateral ilium for the screw fixation is determined to be 10 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 40 mm superior to the greater sciatic notch. The inclination of the lag screw should be 55 degrees at the caudal direction in the sagittal plane and 40 degrees in the horizontal plane. It is safe to place the lag screw in the anterior column with the help of the targeting device.