Harinathan Balaji, Jebaseelan Davidson, Yoganandan Narayan, Vedantam Aditya
Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA.
School of Mechanical Engineering, Vellore Institute of Technology, Chennai, India.
Asian Spine J. 2024 Dec;18(6):777-793. doi: 10.31616/asj.2024.0179. Epub 2024 Dec 24.
This study employed a patient-specific finite element model.
To quantify the effect of anterior and posterior surgical approaches on adjacent segment biomechanics of the patient-specific spine and spinal cord.
Adjacent segment degeneration (ASD) is a well-documented complication following cervical fusion, typically resulting from accelerated osteoligamentous deterioration and subsequent symptomatic neural compression. Despite the known impact of spinal fusion on adjacent segment biomechanics, comprehensive comparison between anterior and posterior surgical approaches remains elusive. Understanding these biomechanical changes is crucial for predicting and managing ASD, thereby aiding preoperative surgical planning.
Patient-specific finite element modeling (FEM) of the cervical spine and spinal cord were created. Surgical simulation was performed for multi-segment anterior cervical discectomy fusion (ACDF) (C4-C7) and posterior cervical laminectomy with fusion (PCLF) (C5-6 laminectomy and C4-C7 fusion). Physiological motions were simulated by applying a 2 Nm moment and 75 N force.
At the superior adjacent segment, the ACDF model exhibited a higher range of motion (ROM) during neck flexion compared to PCLF. Conversely, in neck extension, PCLF showed a higher ROM than ACDF. At the superior adjacent segment, the ACDF model showed greater spinal cord stress during flexion. During extension, PCLF was associated with greater spinal cord stress. At the inferior adjacent segment, ACDF was associated with greater spinal cord stress than PCLF during flexion. At the superior adjacent segment, ACDF also led to increased intradiskal pressure and capsular ligament strain during flexion, whereas PCLF showed these increases during extension.
Our findings indicate the differential effect of ACDF and PCLF on biomechanics at the cervical spine's adjacent segments, with the patient-specific model with ACDF showing greater changes and potential for degeneration. This study highlights the utility of patient-specific FEMs in enhancing surgical decision-making through personalized medicine.
本研究采用了患者特异性有限元模型。
量化前后路手术入路对患者特异性脊柱和脊髓相邻节段生物力学的影响。
相邻节段退变（ASD）是颈椎融合术后一种有充分文献记载的并发症，通常是由于骨韧带加速退变以及随后出现有症状的神经受压所致。尽管已知脊柱融合对相邻节段生物力学有影响，但前后路手术入路之间的全面比较仍然难以实现。了解这些生物力学变化对于预测和管理ASD至关重要，从而有助于术前手术规划。
创建了颈椎和脊髓的患者特异性有限元模型（FEM）。对多节段颈椎前路椎间盘切除融合术（ACDF）（C4 - C7）和颈椎后路椎板切除融合术（PCLF）（C5 - 6椎板切除及C4 - C7融合）进行了手术模拟。通过施加2 Nm力矩和75 N力来模拟生理运动。
在上位相邻节段，与PCLF相比，ACDF模型在颈部前屈时表现出更大的活动度（ROM）。相反，在颈部后伸时，PCLF的ROM高于ACDF。在上位相邻节段，ACDF模型在前屈时脊髓应力更大。在伸展时，PCLF与更大的脊髓应力相关。在下位相邻节段，ACDF在前屈时脊髓应力比PCLF更大。在上位相邻节段，ACDF在前屈时还导致椎间盘内压力和关节囊韧带应变增加，而PCLF在伸展时出现这些增加。
我们的研究结果表明ACDF和PCLF对颈椎相邻节段生物力学有不同影响，采用ACDF的患者特异性模型显示出更大的变化和退变潜力。本研究强调了患者特异性有限元模型在通过个性化医疗加强手术决策方面的实用性。
