Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, 391 Binshui West Road, Xiqing District, Tianjin, 300384, China.
Department of Spine Surgery, Tianjin Hospital, Tianjin University, 406 Jiefang South Road, Tianjin, 300211, China.
BMC Musculoskelet Disord. 2022 Aug 19;23(1):794. doi: 10.1186/s12891-022-05645-7.
Oblique lumbar interbody fusion (OLIF) is an important surgical modality for the treatment of degenerative lumbar spine disease. Various supplemental fixations can be co-applied with OLIF, increasing OLIF stability and reducing complications. However, it is unclear whether osteoporosis affects the success of supplemental fixations; therefore, this study analyzed the effects of osteoporosis on various supplemental fixations co-applied with OLIF.
We developed and validated an L3-S1 finite element (FE) model; we assigned different material properties to each component and established models of the osteoporotic and normal bone lumbar spine. We explored the outcomes of OLIF combined with each of five supplemental fixations: standalone OLIF; OLIF with lateral plate fixation (OLIF + LPF); OLIF with translaminar facet joint fixation and unilateral pedicle screw fixation (OLIF + TFJF + UPSF); OLIF with unilateral pedicle screw fixation (OLIF + UPSF); and OLIF with bilateral pedicle screw fixation (OLIF + BPSF). Under the various working conditions, we calculated the ranges of motion (ROMs) of the normal bone and osteoporosis models, the maximum Mises stresses of the fixation instruments (MMSFIs), and the average Mises stresses on cancellous bone (AMSCBs).
Compared with the normal bone OLIF model, no demonstrable change in any segmental ROM was apparent. The MMSFIs increased in all five osteoporotic OLIF models. In the OLIF + TFJF + UPSF model, the MMSFIs increased sharply in forward flexion and extension. The stress changes of the OLIF + UPSF, OLIF + BPSF, and OLIF + TFJF + UPSF models were similar; all stresses trended upward. The AMSCBs decreased in all five osteoporotic OLIF models during flexion, extension, lateral bending, and axial rotation. The average stress change of cancellous bone was most obvious under extension. The AMSCBs of the five OLIF models decreased by 14%, 23.44%, 21.97%, 40.56%, and 22.44% respectively.
For some supplemental fixations, the AMSCBs were all reduced and the MMSFIs were all increased in the osteoporotic model, compared with the OLIF model of normal bone. Therefore, the biomechanical performance of an osteoporotic model may be inferior to the biomechanical performance of a normal model for the same fixation method; in some instances, it may increase the risks of fracture and internal fixation failure.
斜侧腰椎体间融合术（OLIF）是治疗退行性腰椎疾病的重要手术方式。OLIF 可与各种附加固定物联合应用，增加 OLIF 的稳定性，减少并发症。然而，骨质疏松是否会影响附加固定物的成功率尚不清楚，因此本研究分析了骨质疏松对 OLIF 联合应用的各种附加固定物的影响。
我们建立并验证了 L3-S1 有限元（FE）模型；我们为每个组件分配了不同的材料特性，并建立了骨质疏松和正常骨腰椎的模型。我们探讨了 OLIF 联合五种附加固定物的结果：单纯 OLIF；OLIF 加侧方板固定（OLIF+LPF）；OLIF 加经椎间关节突关节固定和单侧椎弓根螺钉固定（OLIF+TFJF+UPSF）；OLIF 加单侧椎弓根螺钉固定（OLIF+UPSF）；OLIF 加双侧椎弓根螺钉固定（OLIF+BPSF）。在各种工作条件下，我们计算了正常骨和骨质疏松模型的运动范围（ROM）、固定器械的最大 Mises 应力（MMSFI）和松质骨的平均 Mises 应力（AMSCB）。
与正常骨 OLIF 模型相比，各节段 ROM 无明显变化。五种骨质疏松 OLIF 模型的 MMSFI 均增加。在 OLIF+TFJF+UPSF 模型中，前屈和伸展时 MMSFI 急剧增加。OLIF+UPSF、OLIF+BPSF 和 OLIF+TFJF+UPSF 模型的应力变化相似；所有应力均呈上升趋势。在五种骨质疏松 OLIF 模型中，屈伸、侧屈和轴向旋转时 AMSCB 均减小。伸展时松质骨的平均应力变化最明显。OLIF 五种模型的 AMSCB 分别减少了 14%、23.44%、21.97%、40.56%和 22.44%。
与正常骨 OLIF 模型相比，对于某些附加固定物，骨质疏松模型的 AMSCB 减小，MMSFI 增大。因此，对于相同的固定方法，骨质疏松模型的生物力学性能可能低于正常模型的生物力学性能；在某些情况下，它可能会增加骨折和内固定失败的风险。
