Ogon M, Haid C, Krismer M, Sterzinger W, Bauer R
Department of Orthopaedic Surgery, University of Innsbruck, Austria.
Spine (Phila Pa 1976). 1996 Dec 1;21(23):2728-34. doi: 10.1097/00007632-199612010-00005.
The advantage to fixation strength of triangulated, double-screw fixation compared with that of single-screw instrumentation in anterior spine surgery was evaluated by in vitro testing.
To compare the fixation strength of single-screw instrumentation with ventral derotation spondylodesis screws with the fixation strength of triangulated, double-screw instrumentation with Cotrel-Dubousset-Hopf screws. Resistance against pull-out load and against load perpendicular to the axis of the screws was evaluated. To avoid the bias caused by different screw design, the pull-out strength of single screws of both devices was compared first.
To the authors' knowledge, no study comparing anterior single with triangulated screws has been published.
A pull-out test was performed when one vertebra in each spine specimen was instrumented with a ventral derotation spondylodesis screw, one with an isolated Cotrel-Dubousset-Hopf screws, and one with two triangulated, Cotrel-Dubousset-Hopf screws linked by a Cotrel-Dubousset-Hopf block. Load perpendicular to the axis of the screw was applied on the bone-device interface after instrumentation of further specimens with ventral derotation spondylodesis and triangulated, Cotrel-Dubousset-Hopf devices.
Use of isolated Cotrel-Dubousset-Hopf screws compared with ventral derotation spondylodesis screws showed no significant differences in pull-out strength. The use of triangulated, double-screw fixation with Cotrel-Dubousset-Hopf screws led to a significant 79% increase in resistance against pull-out and a 73% increase in resistance against load perpendicular to the screw axis compared with the resistance produced using ventral derotation spondylodesis single-screw instrumentation.
In anterior surgery, fixation of the vertebra-device interface can be improved considerably by application of two triangulated screws.
通过体外测试评估在脊柱前路手术中，三角双螺钉固定相对于单螺钉器械固定在固定强度方面的优势。
比较腹侧旋转去旋转脊柱融合螺钉单螺钉器械固定的固定强度与使用 Cotrel-Dubousset-Hopf 螺钉的三角双螺钉器械固定的固定强度。评估抗拔出载荷和抗垂直于螺钉轴线载荷的能力。为避免不同螺钉设计造成的偏差，首先比较两种器械单螺钉的拔出强度。
据作者所知，尚无比较前路单螺钉与三角螺钉的研究发表。
对每个脊柱标本中的一个椎体分别用腹侧旋转去旋转脊柱融合螺钉、单独的 Cotrel-Dubousset-Hopf 螺钉以及由 Cotrel-Dubousset-Hopf 连接块连接的两个三角 Cotrel-Dubousset-Hopf 螺钉进行器械固定后，进行拔出试验。在用腹侧旋转去旋转脊柱融合器械和三角 Cotrel-Dubousset-Hopf 器械对更多标本进行器械固定后，在骨 - 器械界面施加垂直于螺钉轴线的载荷。
与腹侧旋转去旋转脊柱融合螺钉相比，单独使用 Cotrel-Dubousset-Hopf 螺钉的拔出强度无显著差异。与使用腹侧旋转去旋转脊柱融合单螺钉器械固定产生的阻力相比，使用三角双螺钉 Cotrel-Dubousset-Hopf 螺钉固定导致抗拔出阻力显著增加 79%，抗垂直于螺钉轴线载荷的阻力增加 73%。
在脊柱前路手术中，应用两个三角螺钉可显著改善椎体 - 器械界面的固定。
