Indications for Use: The Superion™ Indirect Decompression System (IDS) is indicated to treat skeletally mature patients suffering from pain, numbness, and/or cramping in the legs (neurogenic intermittent claudication) secondary to a diagnosis of moderate degenerative lumbar spinal stenosis, with or without Grade 1 spondylolisthesis, having radiographic evidence of thickened ligamentum flavum, narrowed lateral recess, and/or central canal or foraminal narrowing. The Superion™ Interspinous Spacer is indicated for those patients with impaired physical function who experience relief in flexion from symptoms of leg/buttock/groin pain, with or without back pain, who have undergone at least 6 months of non-operative treatment. The Superion™ Interspinous Spacer may be implanted at one or two adjacent lumbar levels in patients in whom treatment is indicated at no more than two levels, from L1 to L5. Contraindications, warnings, precautions, side effects. The Superion™ Indirect Decompression System (IDS) is contraindicated for patients who: have spinal anatomy that prevent implantation of the device or cause the device to be unstable in situ (i.e., degenerative spondylolisthesis greater than grade 1), Cauda equina syndrome, or prior decompression or fusion at the index level, scoliosis or spinous process fractures, osteoporosis, infection, allergy or reaction to any metal or implant or a high Body Mass Index. Avoid strenuous activity for 6 weeks after surgery, contact your physician if there is fluid leaking from your incision, if you have pain, swelling or numbness in your legs or buttocks or if you fall. Refer to the Instructions for Use provided on www.vertiflex.com for additional Indications for Use, contraindications information and potential adverse effects, warnings, and precautions prior to using this product. Caution: U.S. Federal law restricts this device to sale by or on the order of a physician.