Total disc replacement has been introduced to avoid the biomechanical changes often caused in adjacent segments by the traditional fusion of two or more vertebrae in the lumbar spine. It also aims to maintain mobility and eliminate pain. Total disc replacement using a flexible prosthesis is currently a popular solution. The main indication for this procedure is low back pain caused by disc degeneration. Diagnostic procedures are important to correctly identify and localize the affected disc. To this end, discography represents the most reliable test; however, imaging and clinical investigations are also important adjuncts. To date, there are insufficient long-term data available on the relatively new total disc replacement technique to be able to confirm its superiority compared to traditional fusion procedures in terms of low back pain and patient satisfaction, but short- and mid-term results indicate that, when correctly indicated, both procedures have similar outcomes.