Interspinous device

Last revised by Henry Knipe on 10 Aug 2021

Implantation of interspinous devices is one option for treating lumbar canal stenosis and other causes of low back pain. These devices attempt to produce lumbar flexion by distracting the lumbar spinous processes restoring height and resulting in tightening of the thickened ligamentum flavum, and widening of the central canal and neural exit foramen 1,5. They can also unload the facet joints and provide spinal stability 4

  • neurogenic claudication secondary to lumbar canal stenosis that is relieved with flexion that has failed conservative treatment 1
  • salvage/rescue treatment for recurrent neurologic claudication syndrome post-laminectomy, adjacent segment degeneration or spinal stimulator implantation 3
  • grade I degenerative spondylolisthesis
  • discogenic low back pain
  • non-traumatic instability
  • facet syndrome 4

Contraindications will vary depending on the device but generally include 1:

  • low back pain without groin, buttock or lower limb radiation
  • previous spinal fusion or decompression at the target level
  • compression fracture
  • severe facet joint hypertrophy requiring resection leading to instability
  • ≥grade 2 spondylolisthesis
  • spondylolytic spondylolisthesis
  • severe lumbar scoliosis
  • osteoporosis

There are a number of devices available 1,4:

  • motion-preserving devices
    • static/rigid: made from non-compressible material to ensure consistent spinous process distraction
    • dynamic/flexible: made from compressible material that can act as a shock absorber during extension
  • fusion devices: an alternative to pedicle screw and rod fixation when used with other devices for spinal fusion

The technique will depend on the device but the procedure is generally considered minimally invasive 4. Interspinous devices can be implanted as a standalone procedure although some (e.g. Coflex®) are designed to be implanted after spinal decompression 1

Approximately 33% of patients will develop new or worsening pain and ~15% will require reoperation 5. Short-term (6 months) pain relief and reduction in disability is similar to decompressive surgery but the long-term (2+ year) effectiveness of these devices has yet to be established 5

  • wound complication: ~15% 5
  • spinous process fracture: ~5% 1,5
  • device loosening, breakage or migration: ~ 4% 2,5
  • deep infection: ~1% 5

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2: displaced
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.