Department of Orthopaedics and Rehabilitation, Walter Reed Army Medical Center, Washington, DC, USA.
Spine (Phila Pa 1976). 2009 Nov 15;34(24):E866-72. doi: 10.1097/BRS.0b013e3181bf94f0.
Comparative biomechanical testing in calf spines.
To biomechanically evaluate 4 techniques of lumbosacral fixation.
Pelvic fixation is a problematic area, and currently, the preferred method of pelvic fixation is controversial. Clinically, iliac screws have demonstrated decreased rod breakage rates, and better correction of pelvic obliquity than unthreaded rods (Galveston technique), but several modern methods of iliac fixation have not been compared.
A total of 32 male calf spines were tested under axial rotation, flexion/extension, and lateral bending. Following intact testing, specimens were instrumented in the following groups: group 1-Modified Galveston technique with rods connected directly to iliac screws (no S1 fixation); group 2-S1 screws and iliac screws with offset connectors distal to S1; group 3-S1 screws and iliac screws with offset connectors coupled to the longitudinal rod between L6 and S1; and group 4-S1 and S2 screws without iliac fixation. Pedicle screws were placed from L3 to L6. Following nondestructive testing, specimens were fixed at the cephalad aspect of the construct and flexed to failure, with peak failure moment (Nm).
Group 1 demonstrated significantly more flexion/extension than groups 2, 3, 4 (P<0.001). There were no significant differences between groups for lateral bending or axial rotation at L3-S1 or L6-S1. During destructive testing, group 4 showed a significant reduction in peak failure compared to group 1 (P<0.001), group 2 (P=0.001), and group 3 (P<0.001). There was no significant difference between groups 1, 2, and 3 and all specimens failed at the distal fixation.
With extension of instrumentation across the lumbosacral junction, our results indicate significant improvement in stability with the use of S1 screws and iliac screw fixation. Furthermore, there does not appear to be any significant difference in the location of the connector for the iliac screw.
小牛脊柱的比较生物力学测试。
生物力学评估 4 种腰骶固定技术。
骨盆固定是一个有问题的领域，目前，骨盆固定的首选方法存在争议。临床上，髂螺钉已证明可降低杆断裂率，并比未上螺纹的杆（Galveston 技术）更好地纠正骨盆倾斜，但尚未比较几种现代的髂固定方法。
32 个雄性小牛脊柱在轴向旋转、屈伸和侧屈下进行测试。在完整测试后，标本被以下组进行仪器化：组 1-改良 Galveston 技术，将杆直接连接到髂螺钉（无 S1 固定）；组 2-S1 螺钉和髂螺钉，在 S1 下方使用偏移连接器；组 3-S1 螺钉和髂螺钉，与 L6 和 S1 之间的纵向杆耦合的偏移连接器；组 4-S1 和 S2 螺钉，无髂固定。椎弓根螺钉从 L3 放置到 L6。在非破坏性测试后，标本在构建物的头侧固定并弯曲至失效，记录峰值失效力矩（Nm）。
组 1 在屈伸时的表现明显优于组 2、3、4（P<0.001）。在 L3-S1 或 L6-S1 处，3 个组之间在侧屈或轴向旋转方面没有显著差异。在破坏性测试中，与组 1（P<0.001）、组 2（P=0.001）和组 3（P<0.001）相比，组 4 的峰值失效明显降低。组 1、2 和 3 之间没有显著差异，所有标本均在远端固定处失效。
随着腰骶关节固定范围的扩大，我们的结果表明，使用 S1 螺钉和髂螺钉固定可显著提高稳定性。此外，髂螺钉连接器的位置似乎没有任何显著差异。
