SLIP II Registry: Spinal Laminectomy Versus Instrumented Pedicle Screw Fusion

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.

Inclusion Criteria:

- 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)

Exclusion Criteria:

- Serious medical illness (ASA Class IV or higher)

- Spondylolysis

- Multilevel spondylolisthesis or high grade spondylolisthesis (grade II or greater than
14mm)