Safety and Effectiveness Study of the TOPS System, a Total Posterior Arthroplasty Implant Designed to Alleviate Pain Resulting From Moderate to Severe Lumbar Stenosis

INCLUSION CRITERIA:

• Moderate to Severe lumbar spinal stenosis at a single level* between L3 - L5, with radiographic confirmation of any one of the following on CT, MRI, plain x-ray or myelography:

  • Evidence of thecal sac and/or cauda equina compression
  • Evidence of nerve root impingement by either osseous or non-osseous elements;
  • Evidence of hypertrophic facets with canal encroachment Moderate/severe spinal stenosis is further defined radiographically as;
  • moderate canal stenosis is a 25-49% reduction in the A/P dimension of the central and/or lateral foramen when compared to adjacent (cephlad) level
  • Severe canal stenosis is defined as 50% or greater reduction in the A/P dimension of the central and/or lateral foramen when compared to the adjacent (cephlad) level **Patients which require minimal decompressive surgery at an adjacent level, may have a laminonotmy or soft tissue resection as long as the decompression does not compromise the stability of the adjacent segment.
• At least six (6) months of failed, conservative treatment prior to surgery, including physical therapy, use of anti-inflammatory medications at maximum specified dosage; administration of epidural/facet injections.
• Age 40-75 years old (male or female).

• Up to one prior surgery without instrumentation implanted at any lumbar vertebral level limited to the following:

  • IDET,
  • laminotomy,
  • laminectomy,
  • foraminotomy
  • Discectomy (that occurred at least three years ago without any reoccurrence of herniation)
• Lower back pain and/or sciatica with or without spinal claudication.
• VAS leg pain of at least 40/100 at baseline.
• Oswestry Questionnaire score of at least 40/100 at baseline.

EXCLUSION CRITERIA:

• Back or non-radicular leg pain of unknown etiology
• Spondylolisthesis Grade II or higher
• Stenosis caused by an extruded spinal disc fragment
• Lytic spondylolisthesis
• More than one (1) motion segment involved in the degenerative pathology to the extent that justifies its inclusion in the surgical procedure, unless a decompression alone can be done at that level without compromising stability.
• Known allergy to titanium and/or polyurethane
• Prior fusion surgery at any lumbar vertebral level with or without instrumentation
• Supplemental interbody support required (e.g., bone graft, spacers, VBRs, or fusion cages)
• Clinically compromised vertebral bodies at the affected level(s) due to any traumatic, neoplastic, metabolic or infectious pathology.
• Scoliosis of greater than ten (10) degrees (both angular and rotational)
• Morbid obesity defined as a body mass index > 40 or a weight more than 100 lbs. over ideal body weight.

Note: Additional inclusion/exclusion criteria are applied. Please contact Impliant for further details.