Post Marketing Clinical Follow up Study for MagnetOs Putty in Patients With Degenerative Disc Disease

Inclusion Criteria: 1. Written informed consent by the patient. 2. Male or female patient ≥ 25 up to and including 75 years old. 3. Patients with degenerative disc disease with up to grade 1 spondylolisthesis and with leg pain requiring 1 to 3 level laminectomy and a single/two-level fusion (L2 - S1). Degenerative disc disease is defined by the presence of one or more of the following: 1. instability (angulation ≥ 5 degrees or translation ≥ 3 mm on flexion/extension radiographs), 2. osteophyte formation of facet joints or vertebral endplates, 3. decreased disc height by \> 2 mm, but dependent upon the spinal level, 4. scarring/thickening of ligamentum flavum, annulus fibrosis or facet joint capsule, 5. disc degeneration and/or herniation, 6. facet degeneration, 7. vacuum phenomenon. 4. Patients with an Oswestry Disability Index (ODI) score ≥ 30. 5. Patients with a Visual Analogue Scale (VAS) leg score ≥ 40. 6. Failed conservative treatment (physical therapy, bed rest, medications, spinal injections or transcutaneous electrical nerve stimulation) for a period of 6 months prior to study enrollment. Exclusion Criteria: Per the current Instruction For Use, MagnetOs Putty must not be used in the following clinical situations: 1. To treat conditions in which general bone grafting is not advisable. 2. In conditions where the surgical site may be subjected to excessive impact or stresses, including those beyond the load strength of fixation hardware (e.g. defect site stabilisation is not possible). 3. In case of significant vascular impairment proximal to the graft site. 4. In case of severe metabolic or systemic bone disorders that affect bone or wound healing. 5. In case of acute and chronic infections in the operated area (soft tissue infections; inflammation, bacterial bone diseases; osteomyelitis). 6. When intraoperative soft tissue coverage is not planned or possible. 7. In direct contact with the articular space. 8. In case of treatment with medication interfering with the calcium metabolism.