Goldberg B A, Lindsey R W, Foglar C, Hedrick T D, Miclau T, Hadad J L
Barnhart Department of Orthopaedic Surgery, Baylor College of Medicine, Houston, Texas, USA.
Spine (Phila Pa 1976). 1998 Mar 1;23(5):585-9. doi: 10.1097/00007632-199803010-00011.
Twenty-four cannulated sacroiliac screws were placed bilaterally into 12 cadaveric pelvi (12 titanium screws and 12 stainless-steel screws) and were imaged using conventional and multiplanar reconstructed computed tomography.
To determine whether sacroiliac screw position assessment relative to the neuroforamen is enhanced by: 1) computed tomography using multiplanar reconstructions and 2) the use of titanium screws rather than stainless-steel screws.
To the authors' knowledge, there have been no prior studies demonstrating the accuracy of multiplanar computed tomography compared with that of conventional (axial) tomography in determining the position of sacroiliac screws relative to the neuroforamen. Although titanium screws have been shown to have less scatter than stainless-steel screws, the effect of alloy composition on the radiographic accuracy of interpreting the screw position relative to the sacral neuroforamen is unknown.
Screws were deliberately placed into: position A, in which the screw did not violate the neuroforamen; position B, in which the threads of the screw came within 3 mm of the neuroforamen; and position C, in which the screw clearly was nearly centered in the neuroforamen. The degrees of accuracy in assessing screw position relative to the neuroforamen using conventional (axial) images and using multiplanar reconstructed images were compared.
The axial images were accurate in determining screw position relative to the neuroforamen in 50% of cases in which titanium screws were used and in 42% of cases in which stainless-steel screws were used. The corresponding values for multiplanar reconstructions were 92% for cases in which titanium screws were used and 67% for cases in which stainless-steel screws were used. The accuracy of multiplanar reconstructions was statistically better than that of axial images (P < 0.05). Metallic scatter was increased in stainless-steel screws.
The results of this study suggest that the use of computed tomography with multiplanar reconstruction improves accuracy in determining sacroiliac screw position relative to the neuroforamen. The assessment of screw position may be facilitated using titanium screws.
将24枚空心骶髂螺钉双侧置入12具尸体骨盆（12枚钛螺钉和12枚不锈钢螺钉），并使用传统及多平面重建计算机断层扫描进行成像。
确定相对于神经孔而言，骶髂螺钉位置评估是否因以下因素而得到改善：1）使用多平面重建的计算机断层扫描；2）使用钛螺钉而非不锈钢螺钉。
据作者所知，此前尚无研究证明在确定骶髂螺钉相对于神经孔的位置时，多平面计算机断层扫描与传统（轴向）断层扫描的准确性。虽然已表明钛螺钉的散射比不锈钢螺钉少，但合金成分对解释螺钉相对于骶神经孔位置的放射学准确性的影响尚不清楚。
将螺钉故意置于以下位置：A位，螺钉未侵犯神经孔；B位，螺钉螺纹距神经孔3毫米以内；C位，螺钉明显几乎位于神经孔中心。比较使用传统（轴向）图像和多平面重建图像评估螺钉相对于神经孔位置的准确程度。
在使用钛螺钉的病例中，轴向图像在确定螺钉相对于神经孔位置方面的准确率为50%，在使用不锈钢螺钉的病例中为42%。使用多平面重建时，使用钛螺钉病例的相应值为92%，使用不锈钢螺钉病例的相应值为67%。多平面重建的准确性在统计学上优于轴向图像（P < 0.05）。不锈钢螺钉的金属散射增加。
本研究结果表明，使用多平面重建的计算机断层扫描可提高确定骶髂螺钉相对于神经孔位置的准确性。使用钛螺钉可能有助于评估螺钉位置。
