MRI predictors of revision surgery after primary lumbar discectomy

•Retrolisthesis and foraminal disc herniation increase the risk of revision surgery.•Herniation type and presence of migrated disc do not increase the risk of revision.•Pfirmann grading and Modic changes do not increase the risk of revision.•Consideration of other options such as fusion is warranted in high risk cases. The prognostic significance of preoperative MRI findings in patients undergoing discectomy is incompletely understood. Identifying the radiological predictors of revision surgery on pre-operative MRI can guide management decisions and potentially prevent multiple surgeries. We included 181 patients who underwent primary lumbar discectomy between 2010 and 2014. All patients were contacted via a short telephone interview to determine if they had revision surgery within 5 years of their index surgery. Preoperative MRI of the lumbosacral spine was evaluated for various radiological factors including type of disc herniation, anatomical location of herniation, direction of herniation, degree of disc degeneration, end plate changes and presence of listhesis. Other potential confounders including age, gender, smoking status and index level of surgery were also recorded. Multivariate model of all radiological predictors and confounders were developed and a step-wise approach was used to remove insignificant variables in order to develop final significant multivariate model. P value of