The Relevant Factors Analysis Of Cage Subsidence After Oblique Lumbar Interbody Fusion And How To Prevent It

Purpose of the study: Retrospective analysis of the associated factors of cage subsidence after oblique lateral lumbar interbody fusion(OLIF)and to guide how to prevent cage subsidence after OLIF and to reduce its adverse effects of cage subsidence on the outcomes of lumbar interbody fusion.Research methods: This study collected patients who underwent oblique lateral lumbar interbody from March 2019 and January 2022 at the Department of Spine surgery,Qingdao municipal Hospital,excluding surgical contraindications,and selected a total of97 cases in which the clinical data were complete and more than 1 year follow-up was completed,including 39 males and 58 females with a mean age of 66.57 ± 9.84 years.All included cases were divided into sink versus no sink groups according to the adjudication criteria for subsidence of fusions.According to the subsidence time,the cases in the sink group were divided into two parts,early and delayed subsidence,which were studied separately.Relevant influencing factors analyzed were sex,age,body mass index,bone mineral density,bony endplate destruction,number of fused segments,whether combined posterior pedicle nail fixation was performed,type(size)of fusion apparatus,preoperative vertebral height,postoperative corrected vertebral height,intraoperative corrected vertebral height,preoperative segmental angle,postoperative segmental angle,intraoperative corrected segmental angle,and relevant efficacy indicators,including VAS score ODI score.The clinical data of 97 patients were analyzed statistically using SPSS26.0 software,and the measurement data were expressed as mean ± standard deviation,and independent samples t-test was used for comparison between two groups,and chi square test was used for comparison of count data,with P < 0.05 indicating statistically significant difference.The results of univariate analysis of risk factors affecting postoperative fusion device sinking were finally derived,and multivariate logistic regression analysis was performed based on the results of univariate analysis to derive independent risk factors affecting fusion device sinking.Results:Early cage subsidence after OLIF in univariate analysis,in which there were 25 cases with early sinking occurring after surgery,7 males and 18 females,with a mean age of 68.56 ± 10.34 years,and 72 cases without early fusion device sinking occurring after surgery,32 males and 40 females,with a mean age of 65.88 ± 9.64 years,postoperative cage height,BMD and bony endplates have significantly differences(P <0.05)between the sink and no sink groups,whereas gender,age,BMI(body mass index),number of operative segments,intraoperative and posterior pedicle fixation,fusion vessel model,preoperative cage height,intraoperative corrected cage height,preoperative segment angle,postoperative segment angle Intraoperative correction of segment angle equal to early fusion sink has not significantly differences(P>0.05)between the sink and no sink groups,and no significant differences(P>0.05)of early fusion sink on patient outcomes could be concluded in the VAS score,ODI score.In multivariate analysis,it was concluded that the destruction of bony endplates and BMD were independent risk factors for early postoperative fusion vessel subsidence(P < 0.05).Delayed fusion device sinking after OLIF in univariate analysis,in which 29 cases with delayed sinking occurring after surgery,8 males and 21 females,The mean age was67.34 ± 11.06 years,and a total of 68 cases,31 males and 37 females,with a mean age of66.24 ± 9.34 years,did not exhibit delayed fusion sink after surgery postoperative intervertebral height,BMD,bony endplate destruction,number of operative segments,and type of fusion device have significant differences(P < 0.05)between the sink and no sink groups,whereas gender,age,BMI(body mass index),intraoperative and posterior pedicle fixation,preoperative intervertebral height,intraoperative corrected intervertebral height,preoperative segmental angle,postoperative segmental angle Intraoperative correction of segmental angulation and so on has not significant differences(P>0.05)between the sink and no sink groups associated with delayed fusion sink,and it can be concluded in VAS score,ODI score that delayed fusion sink has no significant effect(P>0.05)on patient outcomes over a 3-month period.However,it had a significant impact(P < 0.05)on patient outcomes at 6 months postoperatively.In the final logistic regression multivariate analysis,it was concluded that the independent risk factors for delayed cage subsidence after surgery were postoperative disc height,BMD,bony endplate destruction,and number of operative intervertebral segments(P < 0.05).Conclusions:1.Bony endplate destruction and bone mineral density are independent risk factors for the sinking of fusion cages in the early postoperative period after OLIF.Postoperative disc height,bony endplate destruction,fusion segment,and bone mineral density were independent risk factors for delayed fusion sink after oblique lateral approach lumbar interbody fusion.2.Factors such as age,gender,body mass index,whether or not combined posterior pedicle nail fixation,preoperative interbody height,intraoperative corrected interbody height,preoperative segmental angle,postoperative segmental angle,intraoperative corrected segmental angle were not significantly associated with early or delayed sinking of the fusion vessel.3.Cage subsidence within 3 months after OLIF is not significantly associated with patient treatment efficacy,whereas it is significantly associated after 6 months.4.Clinical prevention of Cage subsidence after OLIF,the indications for surgery should be strictly grasped preoperatively to minimize the fusion segment,antiosteoporosis treatment should be aggressive preoperatively for osteoporotic patients,paid great attention to preserve the integrity of bony endplates as well as to develop a scientific and complete plan of rehabilitation postoperatively.