The sacroiliac joint (SIJ) constitutes the predominant pain source following lumbar or lumbosacral fusion. Although studies have investigated the biomechanical patterns of SIJ behaviors after lumbosacral fusion, the relationship between ligament strain and SIJ pain following lumbosacral fusion remains unclear. The present study developed a three-dimensional finite element model including L4, L5, sacrum, ilium, SIJ, and seven mainly ligaments. After successful validation, the model was used to investigate the biomechanics of SIJ and ligaments in simulating lumbosacral fusion process. Our results showed that small motion in a stable SIJ may significantly increases the contact pressure and stress of the SIJ, which increase the maximum contact pressure by 171%, 676%, 199%, and 203% and stress by 130%, 424%, 168%, and 241% for flexion, extension, bending, and axial rotation, respectively. An increase in contact pressure and stress in SIJ possibly causes pain at the SIJ, especially in extension and axial rotation. A comparison between the lumbosacral and intact models exhibited the maximum strain increase in the iliosacral ligament (ISL) and the ileal ligament (IL) under all loading conditions. The present study suggests that after lumbosacral fusion process, the ligament sudden increase or decrease is likely to lead sprain or strain ligament, especially ISL and IL thereby causing SIJ pain. This study may contribute to understand the relationship between SIJ ligaments and SIJ pain.

中文翻译：

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腰骶融合术后骶髂关节痛的生物力学评价：有限元分析

骶髂关节 (SIJ) 构成腰椎或腰骶融合术后的主要疼痛源。尽管研究已经调查了腰骶融合术后 SIJ 行为的生物力学模式，但腰骶融合术后韧带应变与 SIJ 疼痛之间的关系仍不清楚。本研究开发了一个三维有限元模型，包括 L4、L5、骶骨、髂骨、SIJ 和七个主要韧带。成功验证后，该模型被用于模拟腰骶融合过程中SIJ和韧带的生物力学研究。我们的结果表明，稳定的 SIJ 中的小运动可能会显着增加 SIJ 的接触压力和应力，从而使最大接触压力增加 171%、676%、199% 和 203%，应力增加 130%、424%、 168%，屈伸 241%，弯曲，和轴向旋转，分别。SIJ 接触压力和应力的增加可能导致 SIJ 疼痛，尤其是在伸展和轴向旋转时。腰骶和完整模型之间的比较显示，在所有负载条件下，髂骶韧带 (ISL) 和回肠韧带 (IL) 的应变增加最大。目前的研究表明，腰骶融合术后，韧带的突然增加或减少很可能导致扭伤或拉伤韧带，尤其是ISL和IL，从而引起SIJ疼痛。这项研究可能有助于了解 SIJ 韧带与 SIJ 疼痛之间的关系。腰骶和完整模型之间的比较显示，在所有负载条件下，髂骶韧带 (ISL) 和回肠韧带 (IL) 的应变增加最大。目前的研究表明，腰骶融合术后，韧带的突然增加或减少很可能导致扭伤或拉伤韧带，尤其是ISL和IL，从而引起SIJ疼痛。这项研究可能有助于了解 SIJ 韧带与 SIJ 疼痛之间的关系。腰骶和完整模型之间的比较显示，在所有负载条件下，髂骶韧带 (ISL) 和回肠韧带 (IL) 的应变增加最大。目前的研究表明，腰骶融合术后，韧带的突然增加或减少很可能导致扭伤或拉伤韧带，尤其是ISL和IL，从而引起SIJ疼痛。这项研究可能有助于了解 SIJ 韧带与 SIJ 疼痛之间的关系。