Analyses Of Risk Factors For Spacer Subsidence Of Cages After Lumbar Fusion

Objective: To review and analyse of risk factors for spacer subsidence of cages after lumbar fusion.Methods: A total of 217 patients with 430 lumbar fusion segments,underwent selective lumbar fusion from March 2013 to March 2015 in The People's Hospital of Guangxi Zhuang Autonomous Region.All were completely followed up for more than 14 months(range 14-37 months,mean 17 months).The spacer subsidence was defined as the last followed-up intervertebral height loss ? 2mm compared with 3 days after the surgery.Risk factors analyzed for spacer subsidence included age,sex,BMI(BMI: body weight kg / height m2),diabetes,hypertension,anemia,fusion segments,preoperative and postoperative intervertebral height,the degree of intervertebral distraction.All the data were analyzed by SPSS 22.0 and performed as mean±SD.Quantitative data between groups using t test;qualitative data and relative risk factors using chi-square test;the independent risk factors of spacer subsidence using logistic regression analysis,P <0.05 have statistically significant.Result: This study found that 57 of 217(26.3%)patients occurred spacer subsidence after selective lumbar fusion.The body Mass index,the numbers of fusion segments,postoperative intervertebral height and the degree of intervertebral distraction are the relatice risk factors of spacer subsidence.Thenumbers of fusion segments and the degree of intervertebral distraction are the independent risk factors for spacer subsidence.Conclusion: We should be aware of preoperative general situation of patients,and control the weight of obese patients actively.In accordance with the principles of surgery to minimize the number of surgical segments.Choose appropriate size of lumbar interbody fusion cage and avoid excessive or deficient opening the intervertebral space.Thus reducing the risk of spacer subsidence.