The Spine SLIP Study

Study Design:
  1. Prospective, randomized, multicenter trial.  Approximately 100 patients would be recruited over one year with follow-up of at least 5 years.
  2. Patients with symptomatic spinal stenosis and single level degenerative grade I (3-14 mm) spondylolisthesis will be treated either with decompressive surgery or decompressive surgery with posterolateral pedicle screw lumbar instrumentation.  Symptomatic spinal stenosis will be defined as radicular and/or back pain either induced by or aggravated by activity and relieved by rest in a patient with either moderately severe or severe lumbar spinal stenosis as defined by an independent radiologist.
  3. Stenosis patients with spondylolysis or patients with high-grade (grade II or greater than 14 mm) spondylolisthesis will be excluded.  Patients with gross instability of the lumbar spine defined as movement on flexion/ extension films greater than 3 mm will be excluded.
  4. Functional Outcomes will be determined using well-known quantitative scales (SF-36 and OSWESTRY scale).  An independent study coordinator will contact patients to gather this information prior to surgery, and after surgery at 6 weeks, 3 months, 6 months, and then annually for 5 years.  Specific functional questions relating to spinal stenosis outcome will also be asked.  Any re-operations for any reason at the original region of stenosis will be noted.
  5. A single independent neuroradiologist will review initial films and determine radiographic outcomes.   Degree of facet removal will be determined using computed tomography done post-opreatively. Fusion will be determined using computed tomography done 6 months, 1 year, and 2 years after surgery.  Studies will be done at the 1 and 2-year interval only if fusion is not demonstrated at 6 months.  Flexion/ Extension views of the lumbar spine will be done at 1 year and 5 years after surgery to determine stability as well as to document any progression of listhesis.
  6. A preliminary statistical review of outcomes will be done after 50% of the patients have completed 2 years of follow-up.  The results of the analysis will be presented to each IRB committee as well as an internal Study Safety Committee.  All deaths within 30 days of operation and all major complications will be reported to the appropriate IRB committee as well as to the Study Safety Committee.