微创医学

目的通过有限元分析经皮椎弓根螺钉内固定术（PPSF）、脊柱前路钢板内固定术（ASPF）及胸椎前路椎体次全切除术与融合术（ATCF）治疗上胸椎骨折的效果。方法选取1名健康成年男性T1～5节段CT数据，建立三维有限元模型，于T3椎体行V型截骨，模拟爆裂性骨折。在T3椎体行V型截骨基础上，构建PPSF、ASPF、ATCF 3种内固定模型。模拟前屈、后伸、左侧弯、右侧弯、左旋转和右旋转6种状态，记录各组最大活动位移（DOM）、最大Von Mises应力。结果骨折组在前屈、后伸、左右侧弯及旋转的整体椎体最大DOM大于PPSF、ATCF、ASPF组，ASPF组在前屈、后伸、左侧弯、右侧弯、左旋转的整体椎体最大DOM大于PPSF、ATCF组，PPSF组在前屈、左侧弯、右侧弯、左旋转、右旋转的整体椎体最大DOM大于ATCF组。骨折组在前屈、后伸、左右侧弯及旋转的T3椎体最大DOM大于ASPF、PPSF、ATCF组，ASPF组在前屈、后伸、左旋转、右旋转的T3椎体最大DOM大于PPSF、ATCF组，PPSF组在左侧弯、右侧弯、左旋转、右旋转的T3椎体最大DOM大于ATCF组。PPSF、ASPF内固定系统最大Von Mises应力发生于旋转，ATCF内固定系统的最大Von Mises应力发生于侧弯；PPSF组前屈、后伸、左侧弯、右侧弯、左旋转、右旋转的最大Von Mises应力大于ASPF组和ATCF组；ASPF组后伸、左侧弯、右侧弯、左旋转、右旋转的最大Von Mises应力大于ATCF组。骨折组左旋转、右旋转的T3椎体最大Von Mises应力大于ATCF组，PPSF组前屈、后伸、左侧弯、右侧弯、左旋转、右旋转的T3椎体最大Von Mises应力大于ASPF组、ATCF组，ASPF组前屈、左侧弯、右侧弯、左旋转、右旋转的T3椎体最大Von Mises应力大于ATCF组。结论 PPSF、ASPF、ATCF 3种手术方式均可有效重建T3椎体上胸椎爆裂性骨折术后脊柱稳定性，整体生物力学稳定性依次为ATCF>PPSF>ASPF。

Objective A finite element analysis was conducted to evaluate the effects of percutaneous pedicle screw fixation (PPSF), anterior spinal plate fixation (ASPF) and anterior thoracic corpectomy and fusion (ATCF) for the treatment of upper thoracic spine fractures. Methods Three-dimensional finite element model of T1-5 was reconstructed using CT scans obtained from a healthy adult male. A V-shaped osteotomy was performed on the T3 vertebra to simulate burst fracture. Based on the V-shaped osteotomy of the T3 vertebra, three internal fixation models including PPSF, ASPF and ATCF were constructed. Six loading conditions including flexion, extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation were simulated. The maximum displacement of motion (DOM) and maximum Von Mises stress in each group were recorded. Results The maximum DOM of the whole vertebra in the fracture group under flexion, extension, bilateral lateral bending and rotation was greater than that in the PPSF, ATCF and ASPF groups. The maximum DOM of the whole vertebra in the ASPF group under flexion, extension, left lateral bending, right lateral bending and left rotation exceeded that in the PPSF and ATCF groups. The maximum DOM of the whole vertebra in the PPSF group under flexion, left lateral bending, right lateral bending, left rotation and right rotation was greater than that in the ATCF group. The maximum DOM of the T3 vertebra in the fracture group under flexion, extension, bilateral lateral bending and rotation was greater than that in the ASPF, PPSF and ATCF groups. The maximum DOM of the T3 vertebra in the ASPF group under flexion, extension, left rotation and right rotation was greater than that in the PPSF and ATCF groups. The maximum DOM of the T3 vertebra in the PPSF group under left lateral bending, right lateral bending, left rotation and right rotation exceeded that in the ATCF group. The maximum Von Mises stress of the PPSF and ASPF internal fixation systems occurred under rotation, while that of the ATCF internal fixation system occurred under lateral bending. The maximum Von Mises stress of the PPSF group under flexion, extension, left lateral bending, right lateral bending, left rotation and right rotation was greater than that of the ASPF and ATCF groups. The maximum Von Mises stress of the ASPF group under extension, left lateral bending, right lateral bending, left rotation and right rotation was greater than that of the ATCF group. The maximum Von Mises stress of the T3 vertebra in the fracture group under left rotation and right rotation exceeded that in the ATCF group. The maximum Von Mises stress of the T3 vertebra in the PPSF group under flexion, extension, left lateral bending, right lateral bending, left rotation and right rotation was greater than that in the ASPF and ATCF groups. The maximum Von Mises stress of the T3 vertebra in the ASPF group under flexion, left lateral bending, right lateral bending, left rotation and right rotation was greater than that in the ATCF group. Conclusion The three surgical techniques including PPSF, ASPF and ATCF could effectively restore spinal stability following T3 upper thoracic burst fracture. The overall biomechanical stability was ranked as ATCF > PPSF > ASPF.

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