• Decompression with or without Fusion in Degenerative Lumbar Spondylolisthesis

    Decompression with or without Fusion in Degenerative Lumbar Spondylolisthesis

    PMID: 34347953


    • Controversy remains whether fusion is beneficial in addition to decompression for patients with lumbar spondylolisthesis.


    • Multi-center, randomized, open-label, parallel group, noninferiority trial.
    • Ages 18-80 with neurogenic claudication or radicular pain that had not responded to 3 months of conservative management.
    • MRI evidence of spinal stenosis and degenerative spondylolisthesis at the stenotic level of at least 3 mm.
    • Excluded if had foraminal stenosis of grade 3 or higher (i.e. deformed nerve root in foramen), previous surgery, or thoracolumbar fracture.
    • Patients assigned 1:1 - decompression versus decompression with instrumented fusion.
    • For those assigned to decompression, a posterior decompression that preserved the midline structures was used.
    • Fusion technique and implants used at discretion of surgeon.
    • Fusion determined by computed tomography at 2 years.
    • Primary outcome: reduction of Oswestry Disability Index by 30% or greater from baseline at 2 years post-operatively, assessed for non-inferiority of decompression alone by difference within 15 percentage points.


    • 267 patients randomized, 134 to decompression alone, 133 to decompression with instrumented fusion.
    • Primary endpoint: 71.4% in decompression alone and 72.9% in the decompression and fusion groups had a reduction of at least 30% in the ODI score, indicating noninferiority of decompression alone.
    • Secondary subgroup analyses: mean duration of surgery, mean length of hospital stay and dural tears were all greater in the instrumented fusion group.
    • Rates of re-operation were not significantly different between the two groups.


    • Variation in surgical approach: bilateral vs. unilateral decompression, interbody cage use.
    • 15 percentage point difference was chosen empirically as no accepted margin for noninferiority exists in literature.
    • Patients were included regardless of the grade of slippage above 3mm and regardless of the result of radiographs to detect dynamic slippage of vertebral bodies.


    • Decompression alone was noninferior to decompression and fusion with respect to the percentage of patients who had a reduction of at least 30% in the ODI score at 2 years after surgery within a margin of 15 percentage points lower.

    This summary was published in Nov. 2021.

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