Study DesignRetrospective Cohort Study.ObjectiveLateral lumbar interbody fusion (LLIF) is a treatment option for correcting lumbar degenerative pathologies that uses a retroperitoneal, transpsoas corridor to the disc space. Conventional teaching of the LLIF technique has been to perform the procedure 'as efficiently as possible', with a goal of keeping the total retractor time to less than 20 minutes to prevent injuries. This study aims to examine the sensitivity of the "20-minute" rule for predicting postoperative femoral nerve palsy.MethodsA multicenter, retrospective cohort of patients who underwent an LLIF was established. Retractor time was recorded and compared to postoperative motor exams for its relationship to motor injury.Results658 total patients were included in the study. The most frequently operated level was L4-5 (71.7%). The average retractor time was 17.5 ± 8.0 minutes. The injury rate of the cohort was 1.8% (12/658). There was no difference in average retractor time for non-injured vs injured patients (17.5 ± 8.0 min vs 19.6 ± 11.2 min,