Coflex PS3 Actual Conditions for Use Study

Inclusion Criteria: 1. Radiographic confirmation of at least moderate lumbar stenosis at one or two contiguous levels from L1-L5 that require surgical decompression. 2. Visual Analog Scale back pain score of at least 50 mm on a 100 mm scale. 3. Neurogenic claudication as defined by leg/buttocks or groin pain that can be relieved by flexion such as sitting in a chair. 4. Subject has undergone at least one lumbar injection at any prior time point, AND/OR at least 6 months of prior conservative care without adequate and sustained symptom relief. 5. Skeletally mature 6. Oswestry Low Back Pain Disability Questionnaire score of at least 20/50 (40%). 7. Psychosocially, mentally, and physically able to fully comply with this protocol, including adhering to scheduled visits, treatment plan, completing forms, and other study procedures. 8. Personally signed and dated informed consent document prior to any study-related procedures indicating that the patient has been informed of all pertinent aspects of the trial. Exclusion Criteria: 1. Prior fusion or decompressive laminectomy at index lumbar level. 2. Radiographically compromised vertebral bodies at any lumbar level(s) caused by current or past trauma or tumor (e.g., compression fracture). 3. Severe facet hypertrophy that requires extensive bone removal which would cause instability. 4. Isthmic spondylolisthesis or spondylolysis (pars fracture). 5. Degenerative lumbar scoliosis (Cobb angle of greater than 25°). 6. Osteoporsis or is at increased risk of osteoporosis. 7. Back or leg pain of unknown etiology. 8. Axial back pain only, with no leg, buttock, or groin pain. 9. Morbid obesity defined as a body mass index \> 40. 10. Known allergy to titanium, titanium alloys, or MR contrast agents. 11. Active or chronic infection - systemic or local. 12. Cauda equina syndrome, defined as neural compression causing neurogenic bowel (rectal incontinence) or bladder (bladder retention or incontinence) dysfunction.