PMCF Study Fortilink-TS Ti

Inclusion Criteria: 1. Willing and able to give voluntary informed consent 2. Skeletally mature patients 3. At least 6 months of non-operative treatment 4. Degenerative disc disease (DDD) of the lumbar spine at one or two contiguous levels between L2 and S1, with DDD being defined as back pain of discogenic origin with degeneration of the disc confirmed by history and radiographic studies, and/or up to grade 1 spondylolisthesis of the lumbar spine at one or two contiguous levels between L2 and S1 Exclusion Criteria: 1. Active systematic infection or an active infection at the operative site 2. A demonstrated allergy or sensitivity to any of the implanted materials 3. Severe osteoporosis (confirmed by imaging in the patient's medical history or during screening) 4. Primary or metastatic tumours affecting the spine (confirmed by imaging in the patient's medical history or during screening) 5. Conditions that may place excessive stresses on the bones and the implants, including but not limited to morbid obesity or other degenerative diseases, at the discretion of the investigator 6. Patients whose ability to follow postoperative restrictions, precautions and rehabilitation programs is limited 7. Fractures, severe deformities or a severe instability in the area of surgery (confirmed by imaging in the patient's medical history or during screening) 8. A medical or surgical situation that would preclude the benefit of surgery 9. Pregnancy 10. Patient's denial for operative treatment, post-operative rehabilitation program, follow up appointments and/or participation in the trial 11. Protocol specified surgical technique cannot be followed for the subject 12. Any other reason (in the judgment of the investigator).