for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
estimated completion



The purpose of this registry is two fold. First, to determine the comparative effectiveness of decompression alone versus decompression with fusion for patients with degenerative grade I spondylolisthesis and symptomatic lumbar spinal stenosis. Primary analysis will focus on the patients' improvement from baseline patient-reported outcome questionnaires. The registry will also determine if an expert panel review of individual patient cases (degenerative grade I spondylolisthesis/stenosis) is associated with improved outcome and patient satisfaction. This study aims to prospectively collect comparative data for these patients treated with either decompression alone or decompression with fusion.

Official Title

SLIP II Registry: Spinal Laminectomy to Laminectomy With Instrumented Pedicle Screw Fusion for Lumbar Stenosis With Grade I Spondylolisthesis


Aim: To conduct a randomized control trial comparing patient outcomes and satisfaction with or without expert panel review before making a final decision about surgery for grade I degenerative lumbar spondylolisthesis. A prospective, multi-center registry aimed at addressing important issues pertaining to outcomes from treatment for degenerative spondylolisthesis and spinal stenosis will be generated. Background: Surgery may be offered to patients with symptomatic lumbar stenosis with degenerative lumbar spondylolisthesis who fail nonoperative treatment measures including physical therapy and epidural steroid injections. For patients with lumbar stenosis without spondylolisthesis, a decompression alone is typical, while those patients who do have degenerative spondylolisthesis and who also have significant mechanical back pain may be offered lumbar decompression with or without fusion. These guidelines were written based upon the SPORT study, which provided the highest quality of evidence available at the time. Additional studies have show that costly interventions such as lumbar fusion may ultimately be cost-effective if they provide durable clinical benefit. Two recent publications in The New England Journal of Medicine present new evidence with conflicting results on superficial review. The Spinal Laminectomy versus Instrumented Pedicle Screw (SLIP) trial provides level I evidence for the efficacy of fusion to improve clinical outcomes and lower reoperation rates compared to a standard laminectomy and medial facetectomy over a four year time frame in patients with neurogenic claudication associated with stable single level spondylolisthesis. Conversely, the Swedish study provides level II evidence that the addition of a variety of fusion techniques does not have significant benefit in the first two years following operation compared to a variety of decompression techniques in a heterogeneous population of patients with stenosis associated with spondylolisthesis. The patient populations treated, surgical techniques used, and outcome measures assessed differed between the two studies and when taken together, underline the need to new comparative effectiveness data for patients with this problem. Plan: Before making a decision regarding which specific operation should be performed in each case, each patient will be randomized to receive an expert panel review or to not receive an expert panel review. For patients who receive an expert panel review, the patients' de-identified lumbar MRI (sagittal and key axial images), 36-inch standing plain radiographs (if available), and flexion and extension radiographs will be uploaded into a web-based platform and reviewed with plans to share the reviews with patients and their treating physicians in real time. For patients who are randomized to no expert panel review, they will discuss with their surgeon the best surgical option for them and proceed as they would in standard of care. Patients with symptomatic lumbar spinal stenosis and single level degenerative grade I spondylolisthesis will be treated either with decompression or decompression with fusion. 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. Patient-reported outcomes will be captured at baseline, at 3 and 6 months, and annually out to five years. Interim Analysis: An interim analysis is planned when 150 patients have reached eligibility at 6 month follow-up. Patients' change from baseline patient-reported outcome questionnaires will be assessed.


Lumbar Spondylolisthesis Grade 1 Spondylolisthesis Lumbar Spinal Stenosis Degenerative Spondylolisthesis Spinal Stenosis Spondylolisthesis Constriction, Pathologic Expert Panel Review


You can join if…

Open to people ages 18 years and up

  • Symptomatic lumbar spinal stenosis: defined as radicular and/or back pain either induced or aggravated by activity and relieved by rest.
  • Single-level grade I degenerative spondylolisthesis (3-14mm)

You CAN'T join if...

  • Serious medical illness (ASA Class IV or higher)
  • Spondylolysis
  • Multilevel spondylolisthesis or high grade spondylolisthesis (grade II or greater than 14mm)


  • University of California, San Fransisco accepting new patients
    San Francisco California 94143 United States
  • Barrow Brain and Spine accepting new patients
    Scottsdale Arizona 85251 United States


accepting new patients
Start Date
Completion Date
Lahey Clinic
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Last Updated