Different internal fixation methods of oblique lateral interbody fusion: a finite element analysis / 医学研究生学报

ABSTRACT

ObjectiveThere is still controversy about which internal fixation method should be used in oblique lateral interbody fusion (OLIF). This paper aims to compare the biomechanical stability of OLIF with different internal fixation methods.MethodsA 31-year-old healthy male volunteer was selected to have a 64-slice spiral CT scan of his lumbar spine. Mimics 19.0, Geomagic Studio 2013, SolidWorks 2017 and other software were used to build a three-dimensional model of L3-L5, and OLIF surgery was simulated to build OLIF finite element models with five different fixation methods: pedicle screw (PS), lateral single rod screw (LSRS), lateral double rod screw (LDRS), lateral single rod screw+ipsilateral translaminar facet screw (LSRS+ITLFS), lateral single rod screw+contralateral translaminar facet screw (LSRS+CTLFS). After validating the validity of the model, the motion modes of spinal flexion, extension, lateral bending and rotation were simulated, and the fixed segment activity and stress distribution characteristics of each model were compared.ResultsIn terms of fixed segment activity, PS had the best fixation effect, and its range of motion (ROM) was the smallest in all 6 modes. The ROM of the vertebral body was maximized when the LSRS was fixed in all directions. LSRS+ITLFS, LSRS+CTLFS and PS had the similar ROM. In terms of maximum stress of cage, PS had the minimum one except in the left bending. LSRS+ITLFS had little stress in all directions except in flexion; LSRS+CTLFS had little stress in all directions except in extension. In terms of the maximum stress in internal fixation, PS had the least one in all directions; LSRS+CTLFS followed, and the maximum stress appeared in extension and right bending (123.05MPA and 91.74MPA, respectively).ConclusionIn OLIF surgery, PS has the best biomechanical effect. LSRS+CTLFS has the similar effect and its clinical operation is simple with relatively small surgical injury, thus providing a reference for clinical choice.