“If it ain’t broke, don’t fix it”. Thomas Bertram Lance’s quote from 1977 is pretty plain but very useful advice, the Interspsinous Device doesn’t follow this advice.
Traditionally, the most effective treatment of lumbar stenosis (compression of the nerve roots) has been decompression with laminectomy. The early Greeks and Byzantines started performing decompressions around 300 A.D. for trauma.
In the 1950s, devices to distract the spinous processes were developed. It is unclear exactly why such a device was needed, considering laminectomy is such a simple and effective procedure for which most people can tolerate. The theory has been that distracting the spinous processes indirectly makes the spinal canal a little larger, but more so that the device prevents the spine from extending which is known to narrow that canal. It does not address rotation or lateral bending. The Interspinous Device also aims to provide stability against progressive instability (spondylolisthesis), retain motion, and prevent further disc space collapse. In the 1950s, the Interspinous Device was largely abandoned due to dislodgement and implant malfunction.
More recently, these devices have resurfaced for an unclear reason.
Multiple studies have evaluated interspinous devices versus decompression (laminectomy) alone or decompression with fusion. In a recent 2021 study comparing the implant to decompression alone, interspinous devices were associated with high complications in the first 90 days following surgery, longer operative time, longer hospital stay, more blood loss, and higher cost compared to decompression alone.
With inferior patient outcomes, good old-fashioned laminectomy may not require an upgrade with an interspinous implant. However we really should not have needed a 2021 study to remind us of similar results from the 1950s.
As Will Durant once said, “So the story of man runs in a dreary circle because he is not yet master of the earth that holds him”
Chou D et al. Efficacy of interspinous device versus surgical decompression in the treatment of lumbar spinal stenosis: a modified network analysis. Evidence-based care journal. 2011
Zhong J et al. Patient outcomes after single-level coflex interspinous implants versus single-level laminectomy. Spine. 2021