Risk factors for cage subsidence following oblique lumbar interbody fusion for patients with lumbar degenerative disease: A retrospective cohort study

Abstract Purpose:To identify potential risk factors for cage subsidence after oblique lumbar interbody fusion (OLIF) using imaging and clinical date, and provide guidance for surgical planning in clinical practice. Methods: Data of 107 patients who underwent OLIF were retrospectively analyzed. Patients with cage subsidence distance＞3 mm were included in the cage subsidence group (CS group), and the remaining patients were involved in the non-cage subsidence group (NCS group). The characteristics (age, gender, Body Mass Index (BMI), main diagnosis, comorbidities etc), vertebral body-related variables (disc height (DH), endplate morphology, and Modic changes) and surgery-related variables (internal fixation, cage position, and endplate injury) were collected. Moreover, the visual analog scale (VAS) score, and the Japanese Orthopedic Association (JOA) score were determined preoperatively, postoperatively, and at follow-up. Firstly, univariate analysis was used to compare the risk factors related to cage subsidence, and then, the multivariate logistic regression analysis was employed to determine the possible risk factors (p＜0.10) for cage subsidence after OLIF. Results:In total, 21 (19.63%) patients were involved in the CS group. The factors significantly associated with cage subsistence included intraoperative endplate injury (odds ratio (OR) =6.620; p=.020), osteoporosis (OR =6.179; p=.004), irregular endplate morphology (OR =5.192; p=.012) and without internal fixation (OR =6.672; p=.013). Conclusion:Cage subsidence did not affect the neurological function, while it led to low back pain in the later stage. The risk factors for cage subsidence included intraoperative endplate injury, osteoporosis, irregular endplate morphology, and treatment with standalone OLIF.