背景：目前内镜微创减压手术已应用于腰椎管狭窄症的治疗，但对镜下精准椎板开窗范围的研究较少。

目的：利用退变腰椎有限元模型，评估分析全内镜下不同分区精准椎板开窗减压手术对腰椎活动度及应力分布的影响。

方法：随机选取1名腰椎管狭窄症患者，采集CT数据，使用相关生物力学软件建立腰椎L4-5节段有限元模型(M1)，并进行有效性验证。继而有限元模拟内镜可视下精准椎板开窗减压手术，结合腰椎管狭窄症临床病理分型，建立椎板开窗减压相应范围L4-5节段手术模型，分别为L4椎板下缘+L4-5关节突关节部分切除模型(M2)、L4-5部分关节突关节+L5椎板上缘切除模型(M3)、L4椎板下缘+L4-5部分关节突关节+L5椎板上缘切除模型(M4)、L4椎板下缘+L4-5部分关节突关节+L5椎板上缘+ Over-the-Top对侧部分关节突切除模型(M5)及L4椎体下缘+L4-5关节突关节1/2以上+L5椎板上缘切除模型(M6)(以上椎体均保留峡部，除M6外，关节突关节均保留50%以上的关节面)。分别对完整脊柱(M1)及5种模拟手术模型(M2、M3、M4、M5、M6)施加相同载荷边界条件，进行前屈、后伸、左/右侧弯、左/右旋转6种工况下腰椎活动度及椎间盘等效应力的对比分析。

结果与结论：①与完整脊柱M1模型比较，M2、M3、M4及M5模型在各工况下活动度值相近，但M6模型的活动度值较M1明显增大，为M1活动度的151%-264%，特别是后伸和旋转工况为甚；②在椎间盘等效应力方面，M2、M3、M4及M5模型在椎间盘前区、左/右区工况下等效应力上升趋势不明显，在椎间盘后区、中区等效应力有所增加，最大增加幅度达53%，但未出现较大应力集中的情况；而M6模型椎间盘各区域等效应力均出现较大程度上升趋势，特别在前屈工况下最大达完整退变模型(M1)的3倍；③结果表明，过大椎板开窗明显影响腰椎稳定性，同时相应节段椎间盘应力增加，易加速椎间关节退变。内镜微创减压手术精准可控，针对不同类型腰椎管狭窄症采用个性化治疗方案，保证减压效果的同时，可有效维持手术节段的生物力学特性。

BACKGROUND:Minimally invasive endoscopic decompression is currently used in the treatment of lumbar spinal stenosis,but there are few studies on the scope of precise laminectomy under the microscope.

OBJECTIVE:To explore the influence of precise decompression with different laminectomy zones on lumbar range of motion and stress distribution using the entire degenerative lumbar finite element model.

METHODS:A patient with lumbar spinal stenosis was randomly on CT data,the lumbar L4-5segment finite element model(M1) was established using relevant biomechanical software,and the validity was that,the finite element simulation of fully endoscopic precisely laminectomy decompression operation was with pathological classification of lumbar spinal stenosis,personalized laminectomy decompression aiming at different L4-5segment stenosis was established,specifically including L4lamina margin and partial facet joint resection model (M2),L5lamina margin and partial facet joint resection model (M3),L4/5lamina margin and partial facet joint resection model (M4),M4 + “Over-the-Top” contralateral partial facet joint resection model (M5),and L4/5lamina margin and over 50% facet jointresection model (M6).The same boundary loading was applied to the various finite element lumbar range of motion and equivalent stress of intervertebral discs were compared under six conditions including flexion,extension,left and right flexion,left and right rotation.

RESULTS AND CONCLUSION:(1) Compared with the entire M1 model,ranges of motion of M2,M3,M4 and M5 models were similar under various conditions,but range of motion of M6 model was significantly increased to 151%-264% scope,especially in the extension and rotational conditions.(2) In terms of the equivalent stress of disc,the M2,M3,M4 and M5 models showed no obvious increasing trend at the anterior,left and right regions under various working largest increase of the equivalent stress at posterior and middle disc regions was 53% maximally,but with no significant stress ,the equivalent stress in total disc regions showed a significant increasing trend in M6 model,especially in flexion condition with the maximum three times of M1 model.(3) Results suggest that extensive laminectomy can significantly affect the stability of the lumbar spine,with the intervertebral disc stress increase at the corresponding segment which is more likely to accelerate segmental invasive endoscopic decompression is precise and personalized decompression schemes can be adopted for different types of lumbar spinal stenosis to ensure the surgery effect and effectively maintain the biomechanical characteristics of the segments.

0 引言 Introduction

随着脊柱内镜的广泛应用，微创治疗已成为腰椎间盘突出症、盘源性腰痛、腰椎管狭窄症等腰椎退行性疾病具有代表性的外科手术方式[1]。与传统开放手术相比，微创内镜手术具有创伤小、治疗精准、疗效满意、术后恢复快、住院时间短等优势[2-3]。随着脊柱微创技术的发展，全内镜下精准定位椎板开窗减压术临床应用逐渐增多，使得腰椎开放椎板开窗减压手术内镜化成为可能。内镜微创手术在几乎不损伤椎旁肌肉的前提下可以精准地进行椎管减压，同时有效控制关节突关节切除范围[4-5]。鉴于内镜微创手术可视化及术中影像学实时监测的特点，相对于开放手术可进行更为精准的减压[6]，该研究旨在通过有限元模拟不同椎板开窗减压术式，进而比较节段的生物力学特性。实验采用相关生物力学软件建立L4-5退变节段有限元模型[7]，用以模拟全内镜下椎板开窗减压不同术式，重点分析腰椎节段活动范围及椎间盘应力等。

文章来源：《精准医学杂志》 网址: http://www.jzyxzz.cn/qikandaodu/2021/0518/519.html