July 20, 2015

Epiduroscopy and low back pain

Interventional pain management has two frontiers to conquer, the treatment of low back pain and the treatment of spinal stenosis.  Today’s blog is about the treatment of low back pain.  Chronic low back pain, defined as pain in the back, with no involvement below the knees has many causes.  We have done a good job of identifying the facet joints and the sacroiliac joints as causes of pain.  The facets cause about 25-45% of low back pain, the discs between 25-40% and the sacroiliac joint about 25%.  If we accept a prevalence of 25% for each of the three, then about 25% of the time, we cannot find a treatment.

We have treatments for facet and sacroiliac joint pain, using radiofrequency techniques for both.  We do not have a good treatment for discogenic or “unknown” pain.  Further, our ability to diagnose discogenic pain is limited by the restrictions we face on doing discography.  Treatments are also frustrating, as modalities such as placing heat across the annulus, as with biacuplasty, provides about 50% relief about 40% of the time.  We would a better means of treating discogenic pain.  Many studies have looked at that problem, injecting such substances as methylene blue, ozone or stem cells into the disc, but nothing has arisen as the convincing treatment.

It may be that these treatments do not work because we have a misunderstanding of cause of low back pain.  There have been many ideas as to why the back hurts.  An easy one to understand and one that I subscribe to is that there is a tear in the annulus, the tough, Michelin tire like outer ring of the disc.  Nerves grow into the tear, while the disc attempts to heal itself.  The healing process generates a number of chemicals in the healing process which are irritating to the nerve, causing it to become inflamed and generate pain signals to the brain.

Some new ideas, or old ideas revisited, have refined this scenario.  In the 1990s, a surgeon named Kuslich did back surgery under local.  It was his work that helped define which structures in the back could generate pain.  One thing Dr. Kuslich saw was that the ventral epidural space was scarred down to the tissues at the back of the disc.  He did not know what to do with this information.  We now believe that this scarring can be a source of pain.  A variant on this idea is that there is a membrane called the Peridural membrane, which is just under the nerve root in the foramen and that it, in like manner, can be a source of pain.

Current efforts to treat disc pain have failed likely because they do not treat the ventral epidural scarring.

Ventral epidural scarring and the Peridural membrane cannot be seen on MRI.  The only way to see it is using epiduroscopy, a technique wherein we place a flexible scope into the epidural space via the sacral hiatus, by the tailbone.  With the epiduroscope, we can release the ventral epidural scarring and the Peridural membrane. With a laser, we can apply heat to the disc, treating the nerves which are sending out pain signals.

The Helm Center is one of the few places who provide epiduroscopy.   Contact us now to see if you might benefit from this treatment!