LimiFlex Clinical Trial for the Treatment of Degenerative Spondylolisthesis With Spinal Stenosis

Inclusion Criteria (patients must meet ALL of the following criteria to be eligible for
participation in the study):

   1. Lumbar degenerative spondylolisthesis (Grade I per Meyerding classification), at one
   level from L1 to S1, with radiographic confirmation using X-ray;

   a. Grade I spondylolisthesis per Meyerding classification includes up to 25% anterior
   translation of a vertebra relative to the superior endplate of the subjacent vertebra
   at the index level. A patient is considered to have spondylolisthesis with a minimum
   10% anterolisthesis at the affected level in a lateral x-ray image.

   2. Lumbar spinal stenosis requiring decompression at up to two contiguous levels from L1
   to S1, inclusive of the level diagnosed with degenerative spondylolisthesis, and
   confirmed radiographically using CT or MRI;

   a. At the index level, lumbar spinal stenosis is at least moderate lumbar canal
   stenosis, defined as more than 25% reduction of the cross-sectional area compared with
   the next adjacent normal level, with nerve root crowding compared with the normal
   level, as determined by the investigator on CT Scan or MRI.

   3. Neurogenic claudication or radiculopathy symptoms including leg pain, muscle weakness,
   and/or sensation abnormality, with or without back pain as evidenced by patient
   history;

   4. Persistent symptoms despite at least 3 months of conservative treatment that may
   include but is not limited to physical therapy, medications, and/or epidural
   injections;

   5. A pre-operative Visual Analog Scale (VAS) leg pain score of ≥50 on a 100 mm scale;

   * Leg pain includes hip and/or buttock pain on the same side

   6. A pre-operative Oswestry Disability Index (ODI) score ≥35 points on a 100-point scale;

   7. Candidate for surgical decompression at a single level or two contiguous levels, with
   stabilization at only one level between L1-S1;

   8. Posterior element anatomy is appropriate for interspinous fixation including
   prediction of presence of spinous processes of segment to be instrumented following
   decompression (investigational AND control groups) and a prediction of >50% of facet
   joints present following decompression (investigational group only);

   9. ≥25-80 years of age and skeletally mature;

10. Patient has the necessary mental capacity to participate and is willing and able to
   participate in the study for the duration of the study follow-up and is able to comply
   with study requirements; and

11. Patient is willing to provide Informed Consent for study participation.

Exclusion Criteria:

   1. A primary and predominate diagnosis of discogenic back pain;

   2. A primary and predominate diagnosis of facet-mediated back pain;

   3. Back or non-radicular leg pain of unknown etiology;

   4. Significant peripheral vascular disease causing vascular claudication;

   5. Significant peripheral neuropathy caused by conditions other than spinal stenosis;

   6. History of fixed or permanent neurological deficit related to spinal cord injury;

   7. History of any previous surgery* at any level in the lumbosacral spine except for a
   discectomy or decompression;

   8. History of any previous surgery* at the level planned for treatment;

      - previous surgery includes spinal stimulator placement but does NOT include
      epidural injections, rhizotomy or nerve ablation.

   9. Isthmic spondylolisthesis or spondylolysis (pars fracture) at any level in the lumbar
   spine;

10. Clinically significant compromise of vertebrae at L1 to S1 levels due to osteoporotic
   vertebral compression fracture or any traumatic, neoplastic, metabolic or infectious
   pathology or congenital abnormality;

11. Spinous process fracture(s) or other posterior element fracture(s) of the segment to
   be instrumented that would preclude secure fixation of the LimiFlex Device to the
   spinous process;

12. Spinous process insufficiency or deformity that would preclude secure fixation of the
   LimiFlex Device to the spinous process including spinous process length <10 mm from
   lamina to dorsal tip or other significant deformity due to trauma, or congenital
   abnormality such as spina bifida occulta at the planned instrumented level that would
   preclude secure fixation of the LimiFlex Device to the spinous process;

13. The estimated distance between the LimiFlex Device strap attachment points (midpoint
   of the cranial edge of the cranial spinous process and the midpoint of the caudal edge
   of the caudal spinous process) is <30mm on pre-operative lateral standing radiographs
   at the segment to be instrumented;

14. Degenerative lumbar scoliosis with a Cobb angle >10° at the affected motion segment;

15. Symptomatic lumbar stenosis that is not amenable to a direct decompression

16. Anklyosed motion segment at the target operative level

17. Severe osteoporosis, defined as history of fragility fracture and DXA T-score <-2.5 or
   QCT T-score <80mg/cubic cm. History of a fragility fracture requires that a DXA scan
   or QCT scan is completed;

18. Planned hip or knee replacement surgery, severe osteoarthritis or other
   musculoskeletal pathology of the hip or leg that could preclude reliable patient self
   reporting assessment scales and/or that would likely progress to surgery during study
   period;

19. Documented allergy to titanium or polyethylene;

20. Active local or systemic infection;

21. Receiving immunosuppressive or long-term steroid therapy;

22. Known history of bone metabolic disorder, including Paget's disease,
   hyperparathyroidism, renal osteodystrophy, and osteomalacia;

23. Disease or condition that would preclude accurate clinical evaluation of the safety
   and effectiveness of the study treatment or any significant medical conditions which
   would place the patient at excessive risk for surgery, such as:

      1. severe rheumatoid arthritis or other severe autoimmune disease

      2. active hepatitis (viral or serum) or HIV positive

      3. unstable cardiac disease

      4. uncontrolled diabetes

      5. renal failure

      6. severe muscular, neural or vascular diseases that endanger the spinal column

      7. cauda equina syndrome

      8. severe neurologic disorders including paralysis

24. Morbid obesity defined as BMI >40;

25. Active malignancy or history of metastatic malignancy within the last five years;

26. Women who are pregnant or are interested in becoming pregnant within the study period;

27. Currently seeking or receiving worker's compensation for back pain or spinal
   condition;

28. Currently involved in spinal litigation that potentially is associated with secondary
   financial gain;

29. Current involvement in a study of another investigational product for similar purpose;

30. Demonstrates three or more Waddell's Signs of Inorganic Behavior;

31. Active treatment of a major psychiatric condition, such as major depression, anxiety
   disorder, bipolar disorder, schizophrenia, personality disorder, that could prevent
   accurate completion of self reporting assessment scales;

32. Current history (within 12 months) of substance abuse, including alcohol abuse; or

33. A prisoner.