Ebraheim N A, Mermer M, Xu R, Yeasting R A
Department of Orthopaedic Surgery, Medical College of Ohio, Toledo 43614, USA.
J Spinal Disord. 1996 Dec;9(6):527-35.
Twelve bony pelves were used in this study. S1 dorsal screws were inserted in the anteromedial, anterior, anterolateral, and anteroinferior directions. When the screws were inserted within 5-10 mm beyond the anterior sacral cortex, radiographs were obtained in the anteroposterior, modified inlet, modified outlet, and lateral projections to evaluate the position of the screws and penetration of the anterior cortex. In addition, 30 dried sacral were obtained for anatomic evaluation focused on the anterior and superior aspect of the sacral alae and its relationship to the anterior aspect of the sacrum. The results showed that a screw penetration of the anterior cortex of the S1 vertebral body or ala is best detected in the modified inlet view. A misdirected screw into the S1 anterior foramen is best seen in the modified outlet view. The lateral view also is useful in determining the extraosseous penetration. The average distance from the anteriormost limit of the ala to the anterior sacral cortex was approximately 11 mm. The average sagittal angle between the superior surface of the ala and S1 dorsal aspect was approximately 51 degrees. This study suggested that the modified inlet and lateral radiograph views are most useful for detecting screw penetration of the anterior cortex of the sacrum. The modified outlet projection is the best for determination of a screw violating the S1 anterior foramen. Also, the modified inlet projection will show the screw orientation relative to the mediolateral plane (the sacral canal and sacroiliac joint), and the lateral view will show the screw direction relative to the superoinferior plane.
本研究使用了12个骨盆骨骼。S1背侧螺钉分别从前内侧、前方、前外侧和前下方方向插入。当螺钉插入骶骨前皮质以外5 - 10毫米范围内时，拍摄前后位、改良入口位、改良出口位和侧位X线片，以评估螺钉位置及前皮质穿透情况。此外，获取30个干燥骶骨用于解剖学评估，重点关注骶骨翼的前上方及其与骶骨前方的关系。结果显示，在改良入口位视图中最易检测到S1椎体或翼的前皮质螺钉穿透情况。在改良出口位视图中最易看到误入S1前孔的螺钉。侧位视图对于确定骨外穿透情况也很有用。翼最前端至骶骨前皮质的平均距离约为11毫米。翼上表面与S1背侧之间的平均矢状角约为51度。本研究表明，改良入口位和侧位X线片视图对于检测骶骨前皮质螺钉穿透最为有用。改良出口位投照最适合确定侵犯S1前孔的螺钉。此外，改良入口位投照将显示螺钉相对于内外侧平面（骶管和骶髂关节）的方向，侧位视图将显示螺钉相对于上下平面的方向。
