方法:生物力学测试和有限元分析。
目的:本研究旨在探讨纤维环(AF)切口大小(RIS,切口宽度与AF高度的比率)和形状会影响椎间盘(IVD)的生物力学。
方法:经过验证的腰椎有限元模型模拟了AF中右后区域的各种切口,不同的大小和形状。模拟包括轴向压缩,屈曲,扩展,弯曲,和旋转。评估的参数包括稳定性,再疝,通过分析应力和IVD退化,高度,椎间盘内压力(IDP),和运动范围(ROM)。
结果:切口在3Nm力矩下增加了AF应力和ROM,随着RIS的增加,价值也在上升。RIS超过40%导致压缩和拉伸过程中AF应力增加20%。而超过50%的RIS导致其他运动中超过20%的AF应力增加。切口应力也随着RIS的升高而增加,特别是超过50%的RIS。IDP在所有切口形状上上升。随着切口增大,终板应力增加(9.9%-48.9%),平均增长12.8%,12.7%,30.5%,圆形为22.8%,椭圆形,正方形,和矩形切口。压缩和旋转对NP压力影响最小(<15%),而屈曲(19.8%-38.8%)和弯曲(18.5%-43.9%)的效果更明显。ROM随RIS增加(20.0%~77.4%),尤其是切口RIS超过40%。
结论:AF损伤提高了AF应力,降低脊柱稳定性,随着RIS的增加,变性风险增加。当RIS超过40%时,再疝的风险增加。圆形或椭圆形切口比方形或矩形切口更好地保持脊柱生物力学。
METHODS: Biomechanical testings and finite element analysis.
OBJECTIVE: This 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.
METHODS: A 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).
RESULTS: Incision 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%.
CONCLUSIONS: AF 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.