Investigating Superion™ In Spinal Stenosis

Inclusion Criteria: * Male or female subjects ≥ 45 years of age * Persistent leg/buttock/groin pain, with or without back pain, that is relieved by flexion activities (example: sitting or bending over a shopping cart) * Diagnosis of degenerative spinal stenosis of the lumbar spine, defined as the narrowing of the midline sagittal spinal canal (central) and/or narrowing between the facet superior articulating process (SAP), the posterior vertebral margin (lateral recess), and the nerve root canal (foraminal) * Must be able to sit for 50 minutes without pain and to walk 50 feet or more Exclusion Criteria: * Axial back pain only * Fixed motor deficit * Diagnosis of lumbar spinal stenosis which requires any direct neural decompression or surgical intervention other than those required to implant the control or experimental device * Unremitting pain in any spinal position * Significant peripheral neuropathy or acute denervation secondary to radiculopathy * Lumbar spinal stenosis at more than two levels determined pre-operatively to require surgical intervention * Significant instability of the lumbar spine as defined by 3mm translation or 5 degrees angulation * Sustained pathologic fractures of the vertebrae or multiple fractures of the vertebrae and/or hips * Spondylolisthesis or degenerative spondylolisthesis greater than grade 1.0 (on a scale of 1 to 4) * Spondylolysis (pars fracture) * Morbid obesity, defined as Body Mass Index (BMI) greater than 40kg/m2 * Insulin-dependent diabetes mellitus * Prior surgery of the lumbar spine * Cauda equina syndrome (defined as neural compression causing neurogenic bowel or bladder dysfunction) * Infection in the disc or spine, past or present * Paget's disease at involved segment or metastasis to the vertebra, osteomalacia, or other metabolic bone disease * Tumor in the spine or a malignant tumor except for basal cell carcinoma * Involved in pending litigation of the spine or worker's compensation related to the back