脊柱内镜不同程度椎间孔一次成形对腰椎稳定性影响

Effects of different degrees of foraminoplasty just once via percutaneous endoscopic lumbar discectomy on lumbar spine stability

目的应用有限元法分析脊柱内镜不同程度椎间孔一次成形对腰椎稳定性的影响。方法建立L3~5有限元模型,于L4~5节段模拟经皮椎间孔入路脊柱内镜手术,分别在环锯直径(d=7.5 mm)的1/3、2/3及3/3位置处平行于冠状面及椎间盘水平切除L4~5左侧关节突腹侧进行椎间孔一次成形。记录不同程度椎间孔一次成形后模型L4~5节段的前屈、后伸、左右侧屈及左右旋转范围和椎间盘最大应力,并与正常模型比较。结果在1/3 d及2/3 d处进行椎间孔一次成形时,运动范围及椎间盘最大应力在各运动状态下较正常均无明显变化。在3/3 d处进行椎间孔成形时,运动范围在右侧屈及右旋转状态下较正常增大;椎间盘最大应力在右侧屈及左右旋转运动状态下较正常增大,但腰椎没有达到失稳状态。结论应用 7.5 mm环锯进行椎间孔一次成形不会破坏腰椎稳定性,但切除较大关节突时存在脊柱侧屈及旋转失稳的趋势,应注意对关节囊和关节面的保护。

Objective To analyze the effects of different degrees of foraminoplasty just once via percutaneous endoscopic lumbar discectomy on lumbar spine stability using the finite element method.Methods A finite element model of L3~5 was constructed,the L4~5 segments were used to simulate percutaneous foraminal approach for spinal endoscopic surgery,the left ventral articular process of L4~5 was removed at 1/3,2/3,3/3 d positions of the circular saw diameter(d=7.5 mm)parallel to the coronal plane and intervertebral disc respectively to establish the L3~5 model after the different degrees of foraminoplasty just once.The range of motion and maximum intervertebral disc stress of the L4~5 segment of the model after different degrees of foraminoplasty just once under anteflexion,extension,lateral bending,axial rotation were recorded,and compared with the normal model.Results The range of motion and the maximum stress of intervertebral disc of L4~5 segment did not change significantly under all exercise states after foraminoplasty just once at 1/3 d and 2/3 d.When foraminoplasty at 3/3 d,the range of motion was larger than normal under right lateral bending and right axial rotation;the maximum stress of the intervertebral disc was larger than normal under right lateral bending and axial rotation,but the lumbar spine did not reach instability.Conclusions Application of 7.5 mm diameter circular saw for foraminoplasty does not destroy lumbar stability,but there is a tendency for lateral bending and rotational instability when resecting large articular process.The protection of the articular capsule and articular surface should be noted.