Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California, San Francisco, San Francisco, CA.
J Orthop Trauma. 2014 Jun;28(6):324-9. doi: 10.1097/BOT.0000000000000018.
Inlet and outlet views are essential in the evaluation of patients with pelvic injuries. The optimal angles that should be used to obtain these views are still debated.
Computed tomography scans of 70 patients without pelvic ring injuries were analyzed. Using the raw data from the computed tomography images, virtual pelvic x-rays were generated. The images were rotated 1 degree at a time and a total of 360 images were generated. The same procedure was repeated to create solid 3-dimensional (3D) reconstructions. Two trauma-trained orthopaedic surgeons then reviewed all 360 images to select inlet and outlet views as described in previous literature. Intraclass correlation coefficients were calculated for each inlet and outlet value.
The average inlet angle (caudal tilt) that was required to achieve a view where the promontory overlaps the S1 body was found to be 26.7 degrees (95% confidence interval, 25-29) with virtual x-rays and 24.3 degrees (95% confidence interval, 22-26) with 3D reconstructions. The average outlet angle (cephalad tilt) that was required to achieve a view where the superior border of the pubic symphysis overlaps the S2 body was 43.7 degrees (95% confidence interval, 42-45) with virtual x-rays and 43.8 degrees (95% confidence interval, 42-45) with 3D reconstructions. There was no difference in these angles based on gender, whereas sacral dysmorphism increased the angle needed to obtain the outlet view by an average of 5 degrees.
This study demonstrated that the ideal angle to obtain inlet views should be approximately 25 degrees and to obtain outlet views should be approximately 45 degrees during screening x-rays to evaluate patients who were diagnosed with pelvic injuries. Application of these new values in the clinical practice would provide higher rates of adequate studies and further prospective clinical studies should be performed to validate these parameters.
入口和出口视图对于评估骨盆损伤患者至关重要。用于获取这些视图的最佳角度仍存在争议。
对 70 名无骨盆环损伤的患者进行计算机断层扫描（CT）检查。使用 CT 图像的原始数据生成虚拟骨盆 X 射线。图像每次旋转 1 度，总共生成 360 张图像。然后重复相同的过程来创建实心三维（3D）重建。两位接受过创伤培训的骨科医生然后审查了所有 360 张图像，以按照之前文献的描述选择入口和出口视图。计算了每个入口和出口值的组内相关系数。
为了获得一个可以使穹窿重叠 S1 体的视图，所需的平均入口角（尾倾）通过虚拟 X 射线发现为 26.7 度（95%置信区间，25-29），而 3D 重建为 24.3 度（95%置信区间，22-26）。为了获得一个可以使耻骨联合上缘重叠 S2 体的视图，所需的平均出口角（头倾）通过虚拟 X 射线为 43.7 度（95%置信区间，42-45），而 3D 重建为 43.8 度（95%置信区间，42-45）。这些角度不受性别影响，但骶骨畸形使获得出口视图所需的角度平均增加了 5 度。
本研究表明，在筛查 X 射线评估诊断为骨盆损伤的患者时，获得入口视图的理想角度约为 25 度，获得出口视图的理想角度约为 45 度。在临床实践中应用这些新值将提供更高比例的充分研究，进一步的前瞻性临床研究应验证这些参数。
