Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Valeo Foshan Technical Center, Foshan, China.
World Neurosurg. 2020 Jan;133:e84-e88. doi: 10.1016/j.wneu.2019.08.113. Epub 2019 Aug 27.
Spinopelvic sagittal parameters have a significant influence on adjacent segment degeneration (ASD) after fusion surgery. The association between ASD and sagittal balance is not well understood. The purpose of this study was to investigate the biomechanical influence of various sacral slope (SS) degrees on adjacent segments after transforaminal lumbar interbody fusion (TLIF) at the L4-L5 level.
We conducted a finite element model of the L1-S1 based on computed tomography scan images. The L1-S1 model with L4-L5 TLIF was modified with various SS degrees (33°, 38°, 43°, and 48°) to investigate the biomechanical influence of SS on adjacent segments. The range of motion (ROM) and intradiscal pressure (IDP) of the adjacent segments (L3-L4 and L5-S1) were compared among models using various SS angles.
When the SS angle increased, the ROM and IDP in L5-S1 decreased gradually after TLIF at the L4-L5 level in all motion patterns. Nevertheless, the ROM and IDP in L3-L4 were not significantly different among various SS angles.
Decreased SS after lumbar fusion surgery may pose a higher risk of ASD. Therefore, restoring appropriate SS should be considered during decision-making prior to fusion surgery to reduce the risk of degenerative changes.
脊柱骨盆矢状参数对融合手术后相邻节段退变（ASD）有重要影响。ASD 与矢状平衡之间的关系尚未得到很好的理解。本研究旨在探讨不同骶骨倾斜度（SS）对 L4-L5 经椎间孔腰椎体间融合术（TLIF）后相邻节段的生物力学影响。
我们基于 CT 扫描图像建立了 L1-S1 的有限元模型。对 L1-S1 模型进行了修改，模拟了 L4-L5 TLIF 手术，并采用不同的 SS 度（33°、38°、43°和 48°），以研究 SS 对相邻节段的生物力学影响。通过各种 SS 角度比较了模型中相邻节段（L3-L4 和 L5-S1）的活动范围（ROM）和椎间盘内压（IDP）。
随着 SS 角度的增加，在所有运动模式下，L4-L5 水平 TLIF 后 L5-S1 的 ROM 和 IDP 逐渐降低。然而，在各种 SS 角度下，L3-L4 的 ROM 和 IDP 没有显著差异。
腰椎融合手术后 SS 减小可能会增加 ASD 的风险。因此，在融合手术前的决策中应考虑恢复适当的 SS，以降低退行性变化的风险。
