Nie Mao-Dan, Huang Ze-Bin, Cheng Rong-Shan, Zhang Qiang, Zhang Ji-Ping, Fu Ling-Jie, Cheng Cheng-Kung
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
Department of Spine Surgery, First Affiliated Hospital of Second Military Medical University, Shanghai, China.
Global Spine J. 2025 May;15(4):1895-1904. doi: 10.1177/21925682241270090. Epub 2024 Jul 30.
Study DesignBiomechanical testings and finite element analysis.ObjectivesThis study aims to investigate how annulus fibrosus (AF) incision size (RIS, Ratio of incision width to AF height) and shape affect intervertebral disc (IVD) biomechanics.MethodsA validated finite element model of lumbar spines simulated various incisions in the middle-right posterior region of the AF, with different sizes and shapes. Simulations included axial compression, flexion, extension, bending, and rotation. Parameters assessed included stability, re-herniation, and IVD degeneration by analyzing stress, height, Intradiscal pressure (IDP), and the range of motion (ROM).ResultsIncision increased AF stress and ROM under 3 Nm moment, with values rising as RIS increased. RIS exceeding 40% resulted in a 20% AF stress increase during compression and extension, while RIS over 50% led to over 20% AF stress increase during other motions. Incision stress also increased with higher RIS, particularly surpassing 50% RIS. IDP rose across all incision shapes. Endplate stress increased (9.9%-48.9%) with larger incisions, with average increases of 12.8%, 12.7%, 30.5%, and 22.8% for circular, oval, square, and rectangular incisions. Compression and rotation minimally affected NP pressure (<15%), while flexion (19.8%-38.8%) and bending (18.5%-43.9%) had a more pronounced effect. ROM increased with RIS (20.0% ∼ 77.4%), especially with an incision RIS exceeding 40%.ConclusionsAF injury elevates AF stress, reduces spine stability, heightens degeneration risk with increasing RIS. Reherniation risk rises when RIS exceeds 40%. Circular or oval incisions maintain spine biomechanics better than square or rectangular ones.
生物力学测试与有限元分析。
本研究旨在探讨纤维环（AF）切口大小（RIS，切口宽度与AF高度之比）和形状如何影响椎间盘（IVD）生物力学。
一个经过验证的腰椎有限元模型模拟了AF右后中部区域不同大小和形状的各种切口。模拟包括轴向压缩、前屈、后伸、侧弯和旋转。通过分析应力、高度、椎间盘内压力（IDP）和运动范围（ROM）来评估的参数包括稳定性、再突出和IVD退变。
在3 Nm力矩下，切口增加了AF应力和ROM，其值随RIS增加而升高。RIS超过40%导致压缩和后伸过程中AF应力增加20%，而RIS超过50%导致其他运动过程中AF应力增加超过20%。切口应力也随较高的RIS增加，特别是超过50% RIS时。所有切口形状下IDP均升高。随着切口增大，终板应力增加（9.9%-48.9%），圆形、椭圆形、方形和矩形切口的平均增加分别为12.8%、12.7%、30.5%和22.8%。压缩和旋转对髓核压力影响最小（<15%），而前屈（19.8%-38.8%）和侧弯（18.5%-43.9%）影响更显著。ROM随RIS增加（20.0% ∼ 77.4%），特别是切口RIS超过40%时。
AF损伤会增加AF应力，降低脊柱稳定性，随着RIS增加，退变风险升高。当RIS超过40%时，再突出风险增加。圆形或椭圆形切口比方形或矩形切口能更好地维持脊柱生物力学。
