Risk Factors for Posterior Cage Migration after Lumbar Interbody Fusion Surgery

A retrospective clinical case series. To determine the strength of association between cage retropulsion and its related factors. Lumbar interbody fusion with cage can obtain a firm union and can restore the disc height with normal sagittal and coronal alignment. Although lumbar interbody fusion procedures have satisfactory clinical outcomes, peri- and postoperative complications regarding the cage remain challenging. From January 2006 to June 2016, 1,047 patients with lumbar degenerative disc disease who underwent posterior lumbar interbody fusion or transforaminal interbody fusion at Gyeongsang National University Hospital were enrolled. Medical records and pre- and postoperative radiographs were reviewed to identify significant cage retropulsion-related factors. The associations between cage retropulsion with various risk factors were evaluated by calculating odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression analysis. Of 1,229 disc levels, 16 cases (1.3%, 10 men and 6 women) had cage retropulsion. Univariate analysis revealed no significant differences between the cage retropulsion group and the no cage retropulsion group with regard to demographic data such as age, sex, weight, height, body mass index (BMI), smoking habits, presence of osteoporosis, and duration of follow-up. Multivariate analysis revealed that low BMI (OR, 0.875; 95% CI, 0.771-0.994; =0.040), presence of screw loosening (OR, 27.400; 95% CI, 7.818-96.033;