The Spine SLIP Study

Objective:

To determine the optimal use of lumbar spinal instrumentation and arthrodesis in patients with single-level degenerative grade I spondylolisthesis and symptomatic spinal stenosis.

Introduction:

To determine the optimal use of lumbar spinal instrumentation and arthrodesis in patients with single-level degenerative grade I spondylolisthesis and symptomatic spinal stenosis.

Degenerative lumbar spinal stenosis is a common cause of debilitating back and leg pain primarily in older people.  There is considerable debate among experts regarding whether or not to perform a fusion in patients with symptomatic spinal stenosis and a degenerative grade I spondylolisthesis.  Instrumented fusions are more expensive, involve more blood loss, take significantly more operating room time, and are associated with more complications; however, it is not established that instrumented fusion is beneficial to patients with spinal stenosis and a grade I degenerative slip.  A few major studies do shed some light on the topic:

  • William Beaumont Hospital Study (1991).  A prospective study of 50 patients found that non-instrumented fusion improved outcome in patients with a single level of spinal stenosis and degenerative spondylolisthesis. (Herkowitz et al, J Bone & Joint Surg, 1991;73:802-808).
  • Washington University Study (1993).   A prospective study of 44 patients found that instrumented fusion prevented progression of spondylolisthesis after lumbar spinal decompression for stenosis and these patients reported better outcomes compared with those patients that developed a progressive slip over time.  (Bridwell et al, J Spine Disorders 1993;6:461-472) .
  • Mayo Clinic Study (1996).  A retrospective study of 124 patients found no compelling evidence to support any fusion for patients with spinal stenosis. (Fox et al, J Neurosurg, 1996;85:793-802).
  • Brigham & Womens Study (1997).  A prospective multicenter study involving 272 patients found that instrumented fusion was associated with more than twice the hospital costs ($25, 914/ patient) compared with decompression alone ($12,615/ patient), while instrumented fusion was not associated with any significant benefit to patients in terms of outcome.   (Katz et al, Spine 1997;22:1123-1131).
  • Cornell Study (1998).  A retrospective analysis of 290 patients treated with a simple decompression only found that only 2.7% of patients required a fusion with an average follow-up time of 1 decade.  (Epstein, J Spinal Disord 1998;11:116-122).
  • Fukushima Medical University Study (2000).  A prospective study of 88 patients found that instrumented Graf stabilization without fusion for patients with degenerative spondylolisthesis improves low back pain but not the recurrence of leg symptoms in patients after 3 years of follow-up. (Konno et al, Spine 2000;5:1533-1537).

There has been no randomized prospective trial to date that addresses the value of instrumented fusion for patients with symptomatic spinal stenosis with a degenerative spondylolisthesis.  Here we propose a prospective multi-center trial aimed at addressing important issues pertaining to outcomes from treatment for degenerative spondylolisthesis and spinal stenosis.  The first phase of this study will be non-randomized.  This initial study aims to evaluate prospectively the outcomes for patients treated either with decompression alone or decompression with posterolateral instrumented fusion.  This will allow the investigators the opportunity to determine the feasibility of performing a prospective, randomized study by determining what percentage of patients would still participate if the study was randomized.