Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea.
Spine J. 2012 Jul;12(7):577-84. doi: 10.1016/j.spinee.2012.07.010. Epub 2012 Aug 22.
There have been several reports describing the usage of subaxial cervical laminar screws. However, the anatomic feasibility of placing such screws has not been thoroughly evaluated yet.
To determine the feasibility of the laminar screw placement in the subaxial cervical spine using a large number of computed tomography (CT) scans and three-dimensional screw trajectory software.
Three-dimensional simulation study of screw placement.
Computed tomography scans of 215 consecutive patients were examined, for a total of 430 screws at each level of the subaxial cervical spine.
Successful screw placement without laminar cortical breach, facet joint violation, and collision between two screws in the same level.
We simulated the placement of 4.0-mm subaxial (C3-C7) cervical laminar screws. Unilateral and bilateral screw placement was simulated, and their success rates were evaluated at each level of the subaxial cervical spine. This study was not supported by any financial sources. One of the authors received royalties for a posterior cervical fixation system, which is not the topic of this article and is not used or mentioned in this article.
The success rate of unilateral screw placement was the highest at C7 (91.4%), followed by C6 (31.9%), C3 (30.2%), C4 (6.3%), and C5 (4.0%). It was significantly higher (p<.001) in men than in women at C6 and C7 but not at the other levels. The success rate of bilateral screw placement was the highest at C7 (68.8%), followed by C3 (13.5%), C6 (8.8%), C4 (1.9%), and C5 (0.9%). It was significantly higher in men (83.5%) than in women (52.0%) at C7 (p<.001) but not at the other levels.
The relatively high success rate at C7, particularly of unilateral placement, suggests that laminar screw placement can be a sound alternative method for fixation at this level. However, careful preoperative CT scan evaluation and patient selection are required, particularly for bilateral fixation in women. At C3 and C6, unilateral screw placement can be considered in approximately 30% of patients after careful selection using preoperative CT scans. At C4 and C5, neither unilateral nor bilateral screw fixation is recommended for most patients.
已经有几篇报道描述了下颈椎椎板螺钉的使用。然而，在下颈椎中放置这些螺钉的解剖学可行性尚未得到彻底评估。
使用大量计算机断层扫描（CT）扫描和三维螺钉轨迹软件来确定在下颈椎椎板中放置螺钉的可行性。
螺钉放置的三维模拟研究。
检查了 215 例连续患者的 CT 扫描，每个下颈椎水平共有 430 枚螺钉。
无椎板皮质破裂、关节突关节侵犯和同一水平两枚螺钉碰撞的成功螺钉放置。
我们模拟了 4.0 毫米下颈椎（C3-C7）椎板螺钉的放置。模拟了单侧和双侧螺钉放置，并评估了在下颈椎各水平的成功率。本研究没有得到任何资金来源的支持。其中一位作者因一种后路颈椎固定系统获得了专利费，但这不是本文的主题，也未在本文中使用或提及。
单侧螺钉放置的成功率最高，C7 为 91.4%，其次是 C6（31.9%）、C3（30.2%）、C4（6.3%）和 C5（4.0%）。男性在 C6 和 C7 明显高于女性（p<.001），但在其他水平则不然。双侧螺钉放置的成功率最高，C7 为 68.8%，其次是 C3（13.5%）、C6（8.8%）、C4（1.9%）和 C5（0.9%）。男性（83.5%）明显高于女性（52.0%）（p<.001），但在其他水平则不然。
C7 处相对较高的成功率，特别是单侧放置的成功率，表明在该水平使用椎板螺钉固定是一种可靠的替代方法。然而，需要进行仔细的术前 CT 扫描评估和患者选择，特别是对于女性的双侧固定。在 C3 和 C6 处，在仔细选择后，大约 30%的患者可以考虑单侧螺钉放置。在 C4 和 C5 处，不建议大多数患者使用单侧或双侧螺钉固定。
