Pedicle Osteotomy for Stenosis Trial

Inclusion Criteria:

1. Is a male or female patient between 40 and 80 years of age.
2. Has the diagnosis of degenerative spinal stenosis of the lumbar region (defined as L2-L5), defined by one or more of the following: a) narrowingof the mid-sagittal spinal canal (central stenosis), b) narrowing between the facet superior articular process (SAP) and the posterior intervertebral disc margin (lateral recess stenosis), c) narrowing of the nerve root foraminal canal(s) (foraminal stenosis) and has, at the same level, radiographic confirmation on plain lateral flexion/extension radiographs of a degenerative grade I spondylolisthesis at the same level, defined as at least 1% but not greater than 25%, offset between the posterior margins of the adjacent vertebral bodies at the index level.
3. Neurogenic claudication or radiculopathic symptoms including leg pain, muscle weakness, and/or sensation abnormality, with or without back pain, which is worse with extended posture and relieved by flexion, as evidenced by patient history.
4. Has pain in the leg and/or buttock that is worse with standing as compared to sitting.
5. Has radiographic confirmation on CT or MRI of moderate or greater lumbar spinal stenosis at the index level defined as \> 25% reduction in area of the central and/or lateral recess and/or foraminal regions of the spinal canal as compared to the adjacent level.
6. Has radiographic confirmation on CT or MRI of compression of the thecal sac and/or cauda equina and/or nerve root(s) due to hypertrophy of the facet joints and/or ligamentum flavum thickening/buckling
7. Has undergone a 6 month or longer course of conservative therapy without sufficient relief of symptoms that has included one or more of the following interventions: physical therapy, bracing, systemic and/or injected medications.
8. Has moderate or greater impairment on the Zurich Claudication Questionnaire (ZCQ) Physical Function scale (PF) defined as a score of 2 or greater.
9. Has moderate or greater impairment on the Oswestry Disability Index defined as a score of 30 or greater.
10. Is a surgical candidate for lumbar decompressive surgery at one or two levels in the L2 through L5 region of the spine.
11. Is psychosocially, mentally and physically able to comply with all study procedures required by the study protocol including attending all scheduled visits and interventions.
12. Is able to provide voluntary, informed consent to participate in the clinical trial and has signed the informed consent documents.

Exclusion Criteria:

1. Has had prior spinal surgery at any level between L1 and S1.
2. Requires more than 2 lumbar levels of surgical decompression.
3. Has a degenerative spondylolisthesis of greater than grade I defined as greater than 25% offset between the posterior margins of adjacent vertebral bodies on plain lateral flexion/extension radiographs or does not have a grade I degenerative spondylolisthesis, defined as 0% offset between the posterior margins of adjacent vertebral bodies on a plain lateral flexion/extension radiograph.
4. Has more than one level of degenerative spondylolisthesis or has spondylolisthesis located at lumbar levels which are not treated with surgical decompression. Has the diagnosis of peripheral neuropathy.
5. Has a complete motor or sensory deficit.
6. Has a pars defect.
7. Has facet joints at the implant level that are absent or fractured.
8. Has lumbar scoliosis with a Cobb angle of greater than 25o.
9. Has a disc herniation at any lumbar level requiring surgical intervention.
10. Has symptomatic hip arthritis or hip pain.
11. Has a Body Mass Index (BMI) of greater than 40.
12. Has a known allergy to titanium or titanium alloys.
13. Has osteoporosis. The SCORE (Simple Calculated Osteoporosis Risk Estimation) will be used to screen subjects who require DEXA; Subjects with T-score \< -2.5 (per The World Health Organization definition) will be excluded.
14. Has a history of Paget's disease, osteomalacia, or any other metabolic bone disease.
15. Has a history of rheumatoid arthritis or other systemic autoimmune disease.
16. Requires medications or drugs known to interfere with bone/soft tissue healing (e.g., chronic systemic corticosteroids). Corticosteroids used for 6 weeks or less are not an exclusion criteria.
17. Has insulin dependent diabetes mellitus.
18. Has cauda equina syndrome, defined as neural compression in the lumbar spine causing neurogenic bowel (rectal incontinence) or neurogenic bladder (bladder retention or incontinence) dysfunction.
19. Only has axial back pain with no leg or buttock pain.
20. Has back or leg pain of unknown etiology.
21. Has evidence or the diagnosis of significant peripheral vascular disease (e.g. diminished or absent dorsalis pedis or posterior tibial pulses)
22. The patient currently has any of the following: schizophrenia, bipolar disorder, major depression, major psychotic disorder, and substance or alcohol abuse or dependency as defined by the DSM V.
23. Has participated in a clinical trial of another investigational drug or device within the past 2 years.
24. Has an active, chronic infection, either systemic or local.