Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, Minnesota, USA.
J Neurosurg Spine. 2011 Feb;14(2):219-25. doi: 10.3171/2010.9.SPINE10254. Epub 2010 Dec 24.
The authors performed a study to determine the optimal iliac screw size, length, and trajectory that produce the highest insertional torques.
Ten fresh cadavers were used and 7.5 × 140-mm and 9.5 × 140-mm iliac screws were placed using 3D image guidance in a randomized fashion in 1 of 2 trajectories. The screws were inserted from the posterior superior iliac spine (PSIS) to either 1) supraacetabular bone or 2) the anterior inferior iliac spine (AIIS). Insertional torque was measured for each full revolution, and the concomitant depth for each torque measurement was recorded. Insertional torque was correlated with detailed bony anatomy.
There was no difference in mean peak insertional torque between the 2 trajectories (25.6 ± 16.4 in-lb [supraacetabular], 26.3 ± 18.2 lb-in [AIIS]; p = 0.8). However, there was a difference between the 2 screw diameters (21.1 ± 10.9 lb-in [7.5-mm-diameter screw], 33.7 ± 19.4 lb-in [9.5-mm-diameter screw]; p = 0.0003). The greatest mean peak insertional torques were observed at depths greater than 80 mm (12.7 ± 9.6 lb-in [≤ 80 mm], 23.7 ± 15.7 lb-in [> 80 mm]; p = 2.6 × 10(-7)). Insertional torque peaks correlated with engagement of the lateral iliac cortex and the superior iliac fossa.
Although the trajectory had no effect on insertional torque, increased torques are achievable by placing larger-diameter and longer screws in proximity to bony landmarks, most of which are at distances greater 80 mm from the entry point at the PSIS. Iliac screws longer than those commonly used in clinical practice can be safely and accurately placed using image guidance, and reproducible screw paths can be achieved.
作者进行了一项研究，以确定产生最高插入扭矩的最佳髂螺钉尺寸、长度和轨迹。
使用三维图像引导，在随机的 2 种轨迹中，在 10 个新鲜尸体中分别使用 7.5×140mm 和 9.5×140mm 髂螺钉。螺钉从后上髂棘（PSIS）插入，分别为 1）髋臼上骨或 2）前下髂棘（AIIS）。测量每个完整旋转的插入扭矩，并记录每个扭矩测量的相应深度。将插入扭矩与详细的骨骼解剖结构相关联。
两种轨迹之间的平均峰值插入扭矩没有差异（髋臼上骨为 25.6±16.4 英寸磅[26.3±18.2 磅英寸]；AIIS；p=0.8）。然而，两种螺钉直径之间存在差异（7.5 毫米直径螺钉为 21.1±10.9 磅英寸，9.5 毫米直径螺钉为 33.7±19.4 磅英寸；p=0.0003）。在深度大于 80mm 时观察到最大平均峰值插入扭矩（≤80mm 为 12.7±9.6 磅英寸，>80mm 为 23.7±15.7 磅英寸；p=2.6×10(-7)）。插入扭矩峰值与髂骨外侧皮质和髂骨上窝的接合有关。
虽然轨迹对插入扭矩没有影响，但通过将更大直径和更长的螺钉放置在靠近骨骼标志的位置，可以获得更大的扭矩，其中大部分标志距离 PSIS 入口点大于 80mm。可以使用图像引导安全且准确地放置长于临床实践中常用的髂螺钉，并且可以实现可重复的螺钉路径。
