The proposed prospective, multi-center, randomized clinical trial is designed to evaluate the safety and effectiveness of the Superion™ ISS compared to the X-STOP® IPD® device in healthy adults suffering from at least 6 months of moderate spinal stenosis symptoms who have been unresponsive to conservative care.

The proposed prospective, multi-center, randomized clinical trial is designed to evaluate the safety and effectiveness of the Superion™ ISS compared to the X-STOP® IPD® device in healthy adults suffering from at least 6 months of moderate spinal stenosis symptoms who have been unresponsive to conservative care. The study endpoint is the rate of overall subject success at 24 months.

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