Background

The expansion of the cervical vertebrae lamina appears to be crucial to related surgical procedures. The dimensions of the groove influence the strain concentration within the lamina of the vertebra and, thus, the potential success or failure of respective surgical procedure. The aim of this computational study is to clarify both the role of the size of the groove with concern to both the open door and the double door laminoplasty techniques.

Methods

Finite element models were created via computer tomography with varying lamina groove dimensions. Displacements were applied to the models at the open side of the vertebral arch and the vertebral body was constrained prior to movement along all the axes. The maximal opening size measured on the inner side of the lamina and the percentage increase in the initial spinal areas were subsequently analyzed.

Findings

The elastic strain concentration value was observed for the groove in all cases, while the maximal principal elastic strain concentration value was observed at the opposite side to the groove cut into the lamina, also in all cases. The maximal area increase related to the 4 mm groove accompanied by the preservation of the ventral cortex of the bone.

Interpretation

The study suggested three conclusions a) the wider the groove, the greater is the opening potential, b) the maximal opening size following laminoplasty is not dependent on the depth of the bone cut for this type of groove, c) no benefit accrues in terms of the opening size following the cutting of a supplementary groove at the beginning of the lamina.

中文翻译：

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椎板成形术的开口尺寸取决于凹槽尺寸：数值研究

背景

颈椎椎板的扩张似乎对相关外科手术至关重要。凹槽的尺寸影响椎板内的应变集中，从而影响相应外科手术的潜在成功或失败。这项计算研究的目的是阐明凹槽尺寸对开门和双门椎板成形技术的作用。

方法

有限元模型是通过计算机断层扫描创建的，具有不同的层槽尺寸。在椎弓的开放侧对模型施加位移，并且在沿所有轴运动之前限制椎体。随后分析了在椎板内侧测量的最大开口尺寸和初始脊柱区域的百分比增加。

发现

在所有情况下都观察到凹槽的弹性应变集中值，而在切入椎板的凹槽的相对侧也观察到最大主弹性应变集中值。最大面积增加与 4 mm 凹槽相关，同时保留了骨的腹侧皮质。

解释

该研究提出了三个结论 a) 凹槽越宽，开口潜力越大，b) 椎板成形术后的最大开口尺寸不依赖于这种凹槽的骨切割深度，c) 没有任何好处在椎板开始处切割辅助凹槽后的开口尺寸。