| Part one Biomechanics of extreme lateral interbody fusion with different internal fixation methods:a finite element analysisObjective:Establishing a normal L3-5 model and using finite element analysis to explore the biomechanical characteristics of extreme lateral interbody fusion(XLIF)with different internal fixation methods.Method:The L3-5 CT image data of a healthy adult male volunteer were selected to establish a normal lumbar finite element model(M0).The range of motion(ROM)of L3-4 and L4-5,under flexion,extension,left bending,right bending,left rotation,and right rotation,together with L3-4 disc pressure,was analyzed after fixing the lower edge of the L5 vertebral body and applying500N pressure and 7.5N torque to the upper edge of the L3 vertebral body.Then the L4-5 intervertebral disc was excised and implanted with an interbody fusion device from the left,supplemented by different types of internal fixation.Six finite element models,including lateral two-hole plate model(M1),lateral four-hole plate model(M2),Verte BRIDGE plating model(M3),lateral pedicle model(M4),posterior unilateral pedicle screw model(M5)and posterior bilateral pedicle screw model(M6)were created.The ROM of L3-4and L4-5,together with the maximum stress value of the cage,and the maximum stress value of the intervertebral disc of L3-4 were analyzed and studied among the six created models.Results:The ROM of L3-4 and L4-5 segments in the validation model under various motion states was basically consistent with previous reports.The lumbar finite element model was validated effectively.After XLIF-assisted internal fixation,the range of activity in L3-4 segments of each internal fixation model was greater than that of the normal model under various working conditions,among which the M5、M6 model had the larger range of activity in flexion and extension,the M6 models had the largest range of motion in left bending and right bending,and the M1 and M2 models had the largest range of motion in left and right rotation.After the internal fixation of L4-5 segments,the mobility in M1-M6 was significantly reduced under various motion patterns.In terms of flexion and extension,the posterior pedicle fixation model(M5,M6)showed a significant reduction,followed by M2,while the M1,M3,and M4 showed a relatively low reduction.The maximal von mises cage stress of M1 was obviously greater than that of other models(except the left bending),and the stresses of M3 and M5 were also relatively high.Compared with M0,the intervertebral disc stress of M1-M6 at L3-4 segments was increased.In the flexion,the stress of M6 was the greatest.The stress of M1 was the highest in the extension.M1 and M2 had the greatest stress in left-right rotation.Conclusions:All fixation models could reduce the mobility of the fusion segment,provide strong stability.The posterior pedicle fixation model provided high stability,followed by the lateral four-hole steel plate model.All fixation models could increase the range of motion and intervertebral disc stress in adjacent segments and increase the incidence of adjacent segment degeneration(ASD).The stress of the cage in lateral two-hole plate model was the largest,followed by Verte BRIDGE plating model and posterior unilateral pedicle screw model,and the risk of cage subsidence is higher in the later stage.Therefore,it is recommended that the posterior bilateral pedicle screw model is the first choice,followed by the lateral four-hole steel plate model for fixation during XLIF surgery.However,it is still necessary to be aware of the occurrence of adjacent segment degeneration in the later stage.Part two Clinical efficacy and complications of extreme lateral interbody fusion with different internal fixation methodsObjective:Retrospective analysis the clinical data of patients with single-segment e Xtreme lateral interbody fusion XLIF),and compare the differences in the efficacy and complications of different internal fixation methods.Method:A retrospective analysis of the data of single-segment XLIF(49)patients in our hospital was divided into lateral fixation group(G1,39 cases,lateral two-hole plate 6 cases,Verte BRIDGE plating 19 cases,and lateral pedicle rod 14 cases)and the posterior bilateral pedicle screw fixation group(G2,10 cases),analyzed the blood loss,operation time,hospitalization time,VAS score,cage subsidence rate,fusion rate,and complications of the two groups.Results:The operation time and blood loss of the G2 group were significantly greater than those of the G1 group,and the difference was statistically significant.The VAS scores in the G1 and G2 group at the last follow-up were significantly lower than those before surgery,and the difference was statistically significant.There was no statistical difference in the preoperative VAS scores between the three groups,but the difference at the last follow-up was significant,G2 was better than G1.G1 and G3 cage subsidence rates were 15.4%and 0%,and cage fusion rates were 92.3%,100%respectively.Complications occurred in 18 patients with an incidence rate of 36.7%,of which G1,G2 were 38.5%and 20%respectively.The highest complications were thigh pain/numbness,psoas weakness(22.4%),followed by cage subsidence(12.2%).Conclusions:XLIF-assisted posterior bilateral pedicle fixation can provide sufficient stability,reduce the risk of cage subsidence,increase the fusion rate,significantly relieve symptoms and reduce the incidence of postoperative complications,but increase the operation time and blood loss.Part three Analysis of the risk factors of cage migration and subsidence after extreme lateral interbody fusionObjective:Analyze the risk factors of the migration and subsidence of the cage after e Xtreme lateral interbody fusion(XLIF),and take corresponding measures in the clinic to reduce the incidence of migration and subsidence.Method:A retrospective analysis of a total of 62 patients with lumbar spinal stenosis treated with XLIF in our hospital from February 2018 to June2021 were divided into group A(cage migration and subsidence,12 cases)and Group B(without cage migration and subsidence,50 cases)based on the follow-up,record factors such as age,gender,body mass index,surgical method,smoking,and bone mineral density(BMD),and compare the two groups.Results:There was no statistically significant difference between group A and group B in terms of age,gender,body mass index,and smoking(P>0.05),while the two groups had statistically significant differences in the BMD(χ~2=6.23,P<0.05).In terms of surgical methods,comparison of Stand-alone XLIF and auxiliary fixation,the differences were statistically significant(χ~2=6.33,P<0.05).Conclusions:Stand-alone and low BMD values were closely related to cage migration and subsidence after XLIF and there was no obvious correlation with age,gender,body mass index,and smoking.However,anti-osteoporosis treatment and the use of posterior bilateral pedicle screw fixation may reduce the migration and subsidence of the cage after surgery. |
PDF Full Text Request