Single Center Study Comparing MOBIS II ST vs MOBIS PEEK

Inclusion Criteria: 1. The patient has symptomatic degenerative disc disease (DDD) at one or two contiguous levels from L2-S1. 2. The patient has documented conservative (non-operative) treatment for at least 6 months. 3. The patient has a VAS back pain of ≥ 60 mm. 4. The patient has an ODI ≥ 40%. 5. The patient is at least 18 years of age and skeletally mature. 6. The general condition of the patient is appropriate for surgery, as evaluated by the Investigator. 7. The patient is willing and able to comply with study requirements. 8. The patient has agreed to participate in the study. Exclusion Criteria: 1. The patient has undergone any prior spinal fusion surgery at the proposed treatment level(s). 2. The patient has osteoporosis or severe osteopenia as determined by the Investigator. A clinical SCORE calculator may be utilized for females over 40 years of age. 3. The patient has grade 2 or higher spondylolisthesis or retrolisthesis at the affected level(s). 4. The patient has diffuse multilevel neoplastic disease such that no adjacent normal segments exist for engagement or instrumentation. 5. The patient has an active infection. 6. The patient is pregnant or is planning on becoming pregnant in the next two years. 7. The patient is mentally ill or has a history of drug abuse or severe depression/ psychosocial issues. 8. The patient has a known allergy to polyether ether ketone (PEEK), stainless steel or tantalum/titanium. 9. The patient is currently enrolled in an investigational spine study. 10. The patient has rheumatoid arthritis, ankylosing spondylitis or other autoimmune disease. 11. The patient has symptomatic fibrous arachnoiditis