Fusion for Lumbar Spinal Stenosis?

Posted by • April 13th, 2016

2016-04-12_12-26-01Back pain does not respect traditional boundaries in healthcare.  Patients with back pain are present in our emergency rooms, our minute clinics, our surgical subspecialty offices, and our inpatient units.  As such, many of us—orthopedist or internist, rheumatologist or advanced practitioner—have had to think about advising the patient with lumbar spinal stenosis or lumbar spondylolisthesis, two of the most common reasons for spinal surgery.  This week’s NEJM includes two studies, the Swedish Spinal Stenosis Study (SSSS) and the Spinal Laminectomy versus Instrumented Pedicle Screw (SLIP) trial, that may prompt us to revisit our views of surgical treatment options for symptomatic lumbar spinal stenosis.

SSSS enrolled patients with symptomatic lumbar spinal stenosis (a narrowing of the spinal canal) with or without degenerative spondylolisthesis (slippage of one vertebral body over another).  Patients were randomized to receive either decompression via laminectomy (removal of the lamina from a vertebral body) or decompression via laminectomy plus spinal fusion (removal of the lamina from a vertebral body followed by the coupling of adjacent vertebral bodies).  The primary outcome was a 2-year follow-up assessment of disability via the Oswestry Disability Index, which is a disease specific outcome measure.  Data on costs were also collected.

Between the 124 patients randomized to the laminectomy alone group and the 123 patients randomized to the laminectomy plus fusion group, the SSSS authors found no significant difference in primary outcome (p=0.24).  This also held true for the subset of patients with spondylolisthesis (p=.11).  The authors did note significantly higher costs for those in the laminectomy plus fusion group compared to the laminectomy alone group.

The SLIP trial enrolled patients with lumbar spinal stenosis and degenerative spondylolisthesis.  Patients were randomized to receive laminectomy alone or laminectomy plus fusion.  The primary outcome was physical health-related quality of life via the SF-36 PCS questionnaire, performed at 2-year follow-up.  Data on operative blood loss, length of operation and length of stay were also collected.

In comparing the 35 patients randomized to the laminectomy alone group and the 31 patients randomized to the laminectomy plus fusion group, the SLIP authors found a significant difference in mean treatment effect of 5.7 points on the SF-36 PCS questionnaire in favor of laminectomy plus fusion (the authors had pre-specified a minimal clinically important difference of 5).  There was no significant difference on the Oswestry Disability Index, a secondary outcome measure.  However, laminectomy plus fusion was associated with significantly greater blood loss, length of operation and length of stay.

How should SSSS and SLIP change our approach to the next patient we see with lumbar spinal stenosis-related back pain? After rapid increases in the utilization of spinal fusion without supportive high-grade evidence, some clinicians may be looking for an affirmation of current practices, and others a reprisal. SSSS and SLIP provide a little of both:

From a clinical outcomes standpoint, SSSS fails to show a benefit for laminectomy plus fusion over laminectomy alone in patients with lumbar spinal stenosis as well as a subgroup of patients who also had degenerative spondylolisthesis.  On the other hand, SLIP, which only examined patients with lumbar stenosis and degenerative spondylolisthesis, showed a modest benefit in physical health-related quality of life for those receiving laminectomy plus fusion.

Despite this, both studies revealed significant drawbacks to the laminectomy plus fusion approach, which was associated with higher costs, greater blood loss, length of operation, and length of stay than laminectomy alone.

When taking a risk-benefit or value-driven approach to the laminectomy plus fusion debate, SSSS and SLIP do not provide a clear winner.  In an accompanying editorial, Drs. Wilco Peul and Wouter Moojen of Leiden University Medical Center in the Netherlands conclude: “Both studies demonstrate clearly that for most stenosis patients surgery should be limited to decompression in absence of overt instability. Evidence from these two trials suggest that fusion in stenosis is no longer best practice and its use should be restricted…”

SSSS and SLIP highlight the need for us to develop better methods of identifying those patients who will benefit most from the laminectomy plus fusion approach, and those who will do best with laminectomy alone.  This is no easy task.  In the meantime, these studies reinforce the importance of prudence, restraint, and personalization of our discussions with patients—in every healthcare venue—regarding treatment options for lower back pain.

Don’t miss the NEJM Quick Take video summary on this study:

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