all patients who received a Arcadius XP L® interbody fusion device between 2016 until approx. January 2021 (minimum Follow-up is one year) in the study center

The ArcadiusXP L® Interbody Fusion System is a stand-alone device intended to be used with four bone screws if no supplement fixation is used to stabilize the lumbar spine through an anterior approach. Levels of anterior lumbar interbody fusion for the indications listed in the instructions for use are from L2-S1.

The Oswestry Disability Index (ODI) is designed to measure back-specific disability. The questionnaire is self-administered and has 10 items concerning pain and activities of daily living including personal care, lifting, walking, sitting, standing, sleeping, sex life, social life and travelling. It is a self-administered questionnaire Each section is scored on a 0-5 scale, 5 is for maximum disability. The index is calculated by dividing the total score by the total possible score, which is multiplied by 100 and expressed as a percentage. The scores for all questions answered are summed, then multiplied by two to obtain the index (range 0 to 100). Zero is equated with no disability and 100 is the maximum disability possible.

Pain will be assessed by the patient using the Visual Analogue Scale (VAS) which state "0" at one end representing "no pain" and "100" at the opposite end representing "maximal/worst pain". Pain will be recorded at minimum 12 months postoperatively, if available in the preoperative clinical routine data, it will also be recorded in the study.