The study is a post-market surveillance study of the Lumbar Implant for Stiffness Augmentation (LISA), a medical device, which is used to treat low-back pain that accompanies degenerative lesions of grades II, III, and IV (Pfirrmann MRI classification). Post-market means the device (i.e. the LISA implant) being used in this study has already obtained CE certification and is commercially available for use in the European market. The LISA device consists of 3 components: A PEEK interspinous spacer, a polyester band, and a titanium blocker. The spacer is positioned between two adjacent spinous processes, the band is belted around the spinous processes and through the spacer, and the blocker is used to lock the band inside the spacer. Medical Device manufacturers conduct post-market clinical studies in order to continuously evaluate the product scientifically and to comply with legal and ethical obligations. With these studies, the long-term safety as well as performance of their medical devices are assessed. This study, which is initiated and sponsored by BACKBONE (LISA designer, developer, manufacturer and marketer), aims to evaluate the long-term safety and performance of the LISA implant for the treatment of lumbar degenerative disease and to evaluate the treatment.