Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
Orthop Surg. 2023 May;15(5):1357-1365. doi: 10.1111/os.13703. Epub 2023 Apr 18.
One well-liked less invasive procedure is oblique lumbar interbody fusion (OLIF). The biomechanical characteristics of double-level oblique lumbar interbody fusion in conjunction with various internal fixations are poorly understood. The purpose of this study was to clarify the biomechanical characteristics of double-level oblique lumbar interbody fusion for osteoporosis spines using various internal fixation techniques.
Based on CT scans of healthy male volunteers, a complete finite element model of osteoporosis in L1-S1 was established. After validation, L3-L5 was selected as the surgical segment to construct four surgical models: (a) two stand-alone cages (SA); (b) two cages with unilateral pedicle screws (UPS); (c) two cages with bilateral pedicle screws (BPS); and (d) two cages with bilateral cortical bone trajectory screws (CBT). Segmental range of motion (ROM), cage stress, and internal fixation stress were studied in all surgical models and compared with the intact osteoporosis model.
The SA model had a minimal reduction in all motions. The CBT model had the most noticeable reduction in flexion and extension activities, while the reduction in the BPS model was slightly less than that in the CBT model but larger than that in the UPS model. The BPS model had the greatest limitation in left-right bending and rotation, which was greater than the UPS and CBT models. CBT had the smallest limitation in left-right rotation. The cage stress of the SA model was the highest. The cage stress in the BPS model was the lowest. Compared with the UPS model, the cage stress in the CBT model was larger in terms of flexion and LB and LR but slightly smaller in terms of RB and RR. In the extension, the cage stress in the CBT model is significantly smaller than in the UPS model. The CBT internal fixation was subjected to the highest stress of all motions. The BPS group had the lowest internal fixation stress in all motions.
Supplemental internal fixation can improve segmental stability and lessen cage stress in double-level OLIF surgery. In limiting segmental mobility and lowering the stress of cage and internal fixation, BPS outperformed UPS and CBT.
一种广受欢迎的微创手术是斜外侧腰椎椎间融合术（OLIF）。双节段斜外侧腰椎椎间融合术结合各种内固定的生物力学特性知之甚少。本研究旨在阐明骨质疏松脊柱采用各种内固定技术行双节段斜外侧腰椎椎间融合术的生物力学特性。
基于健康男性志愿者的 CT 扫描，建立了 L1-S1 骨质疏松症的完整有限元模型。经过验证后，选择 L3-L5 作为手术节段，构建了四个手术模型：（a）两个独立的 cage（SA）；（b）单侧椎弓根螺钉（UPS）固定的两个 cage；（c）双侧椎弓根螺钉（BPS）固定的两个 cage；（d）双侧皮质骨轨迹螺钉（CBT）固定的两个 cage。研究了所有手术模型的节段活动范围（ROM）、cage 应力和内固定应力，并与完整的骨质疏松模型进行了比较。
SA 模型在所有运动中减少最小。CBT 模型在屈伸活动中减少最明显，而 BPS 模型的减少稍小于 CBT 模型，但大于 UPS 模型。BPS 模型在左右弯曲和旋转方面的限制最大，大于 UPS 和 CBT 模型。CBT 在左右旋转方面的限制最小。SA 模型的 cage 应力最高。BPS 模型的 cage 应力最低。与 UPS 模型相比，CBT 模型在屈曲和 LB、LR 时 cage 应力较大，但在 RB、RR 时略小。在伸展时，CBT 模型的 cage 应力明显小于 UPS 模型。CBT 内固定在所有运动中承受的应力最大。BPS 组在所有运动中的内固定应力最低。
补充内固定可以提高双节段 OLIF 手术的节段稳定性并减轻 cage 应力。在限制节段活动度和降低 cage 和内固定的应力方面，BPS 优于 UPS 和 CBT。
