侧前方入路一体式可撑开可复位椎间融合器的生物力学特征

Biomechanical characteristics of integrated expandable repositionable cage through lateral anterior approach

背景:体外实验证实,采用的一体式椎间融合器虽可以从侧方置入,但其置入体内后不具有调节椎间融合器高度的能力和调节腰椎滑移的复位功能。基于以上原因,课题组设计了一种新型的侧前方入路一体式可撑开可复位椎间融合器(OLIF+IERC),并不断深入研究其生物力学性能。目的:探究OLIF+IERC模型,相比于正常腰椎有限元模型、传统的单纯斜前方腰椎椎间融合术(oblique lumber interbody fusion,OLIF)无螺钉固定系统(Stand-alone OLIF)模型、OLIF联合后路双侧椎弓根钉棒固定(OLIF+BPS)模型的生物力学性能差异。方法:对已建立并验证有效的正常模型(L_(3)-S_(1))进行适当的修改,建立3种OLIF手术有限元模型:Stand-alone OLIF模型、OLIF+BPS模型及OLIF+IERC模型。通过对各模型施加500 N的随动载荷和不同方向上(前屈、后伸、侧弯、轴向旋转)7.5 N·m的力矩载荷,比较不同模型的各生物力学指标差异。结果与结论:①对于L_(4)-L_(5)的运动范围、融合器上最大应力及最大终板应力:OLIF+IERC模型在轴向旋转时低于其他手术模型,Stand-alone OLIF模型在各运动姿态下均最高,OLIF+BPS模型在前屈、后伸及侧弯时最低;②综合分析得出:OLIF+IERC模型的生物力学稳定性、抵抗椎间融合器沉降和椎间盘高度降低的能力,在各运动姿态下均优于Stand-alone OLIF模型,在轴向旋转的运动姿态下优于OLIF+BPS模型;③研究建议:腰椎退行性患者在今后进行手术治疗时,可以考虑采用OLIF联合一体式可伸缩可复位融合器固定的手术方式。该研究为腰椎退行性疾病的治疗提供了有价值的参考。

BACKGROUND:In vitro experiments have confirmed that although the integrated interbody cage can be implanted from the side,it does not have the ability to adjust the height of the intervertebral cage and adjust the reduction function of lumbar spondylolisthesis after implantation.Therefore,the present study designed a new lumbar surgical procedure:oblique lumbar interbody fusion with an integrated expandable repositionable cage fixation(OLIF+IERC),and studied the biomechanical performance of OLIF+IERC.OBJECTIVE:To explore the biomechanical performance differences of the OLIF+IERC surgical model in this study,compared with the normal lumbar spine finite element model,OLIF stand-alone without fixation system(stand-alone OLIF)model,and OLIF with posterior bilateral pedicle screws fixation(OLIF+BPS)model.METHODS:The established and validated normal model(L_(3)-S_(1))was suitably modified to establish three kinds of OLIF surgical models:stand-alone OLIF,OLIF+BPS,and OLIF+IERC designed in this study.By applying a 500 N follower load and a moment load of 7.5 N·m in different directions(flexion,extension,lateral bending,and axial rotation)to each model,the various biomechanical indicators of the different models were compared.RESULTS AND CONCLUSION:(1)For range of motion,maximum cage stress,and maximum endplate stress at L_(4)-L_(5),OLIF+IERC was lower than other surgical models in axial rotation;stand-alone OLIF was highest in all motion postures;OLIF+BPS was lowest in flexion,extension,and lateral bending.(2)Taken together,the biomechanical stability,resistance to cage subsidence,and disc height reduction of OLIF+IERC were superior to stand-alone OLIF in all motion postures and superior to OLIF+BPS in motion posture of axial rotation.(3)This study suggests that OLIF+IERC may be considered as a surgical procedure for future surgical treatment of patients with degenerative disease of the lumbar spine.This study provides a valuable reference for the treatment of lumbar degenerative diseases.