Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-ku, Sungnam 463-707, Republic of Korea.
Spine J. 2011 Apr;11(4):316-23. doi: 10.1016/j.spinee.2011.03.009.
Injury to the internal carotid artery (ICA) is a potentially catastrophic complication of C1-lateral mass (C1-LM) or C1-C2 transarticular screw insertion.
This study was designed to determine the risk of injury to the ICA during placement of these screws using computed tomography angiography (CTA).
Radiographic analysis using CTA.
One hundred sixty CTAs were examined, for a total of 320 ICAs.
Not applicable.
Fine-cut intravenous CTAs with multiplanar and three-dimensional reconstruction were reviewed. The position of the ICA in relation to the anterior cortex (AC) of C1, anterior end of the anterior tubercle (AT), and medial margin of the transverse foramen (TF) was measured bilaterally in three ascending and equidistant levels of the C1-AT.
The position of the ICA in relation to C1 was variable. The average distance between the ICA and the AC of C1 was only 3.7 mm. Furthermore, 96% of the time the posterior margin of the ICA was located posterior to the anteriormost aspect of the anterior C1 tubercle (average distance, 5.4 mm), making the ICA vulnerable to damage if a drill, tap, or screw was inserted to the depth of the anteriormost portion of the AT as seen on a lateral fluoroscopic or radiographic view. The medial margin of the ICA was located medial to the TF (a location potentially vulnerable to injury with bicortical screw placement) less often at the caudal aspect of the C1-AT (54%) than at its middle or cranial aspect (74% and 75%, respectively). No ICAs were located anterior to the medial 30% of the C1-LM or more medially.
Bicortical C1-LM or C1-C2 transarticular screw placement carries a potential risk of ICA injury. Given the wide variation in ICA location relative to C1, if bicortical C1 fixation is required, preoperative CTA should be considered to determine the optimal screw trajectory. In general, inferomedially angulated C1-LM screws appear to be safer with respect to the ICA injury than other potential trajectories.
颈内动脉（ICA）损伤是 C1 侧块（C1-LM）或 C1-C2 经关节螺钉插入术的一种潜在灾难性并发症。
本研究旨在通过计算机断层血管造影（CTA）确定这些螺钉插入过程中 ICA 损伤的风险。
使用 CTA 的影像学分析。
共检查了 160 例 CTA，共 320 条 ICA。
不适用。
对静脉 CTA 进行精细切割，采用多平面和三维重建，在 C1-AT 的三个上升等距水平上，双侧测量 ICA 在前颈 1 侧皮质（AC）、前结节（AT）前缘和横突孔（TF）内侧缘的位置。
ICA 与 C1 的位置是可变的。ICA 与 C1 的 AC 之间的平均距离仅为 3.7 毫米。此外，96%的时间，ICA 的后缘位于前 C1 结节最前缘的后方（平均距离为 5.4 毫米），如果在侧位透视或放射学视图中看到钻头、丝锥或螺钉插入到 AT 的最前缘深度，那么 ICA 就容易受损。ICA 的内侧缘位于 TF 的内侧（在 bicortical 螺钉放置时位置潜在易受伤），在 C1-AT 的尾部（54%）比中部或头部（分别为 74%和 75%）更少见。没有 ICA 位于 C1-LM 前内侧 30%或更内侧。
双皮质 C1-LM 或 C1-C2 经关节螺钉固定术有发生 ICA 损伤的潜在风险。鉴于 ICA 相对于 C1 的位置存在广泛的差异，如果需要双皮质 C1 固定，应考虑术前 CTA 以确定最佳螺钉轨迹。一般来说，相对于其他潜在轨迹，向内侧下倾斜的 C1-LM 螺钉似乎对 ICA 损伤更安全。
