Diagnosis and Treatment of Chronic Low Back Pain
July 26th, 2011 | Author: Pain
Chronic low back pain in the US is a substantial problem, with 90% of Americans dealing with back pain at some point in time. Considering that 90% of that pain goes away within 6 to 12 weeks, that means at any one point in time that 10% of the US is dealing with chronic low back pain.
How often is chronic low back pain coming from facet arthritis or injury? Somewhere between 30 and 40%, according to the literature.
When diagnosing the source of the pain, a definitive answer can be elusive. History, physical examination, and imaging studies are often helpful, however, an exact pain generator is not always established. And when it is established, it is often only partially correct or just plain wrong.
Diagnostic injections, called blocks, are often performed of the facet joint or its nerve supply to establish facet pain. If the joint is a source of pain, then numbing it should decrease the pain being felt. If it is not, the pain number described shouldn’t change. How accurate are these diagnostic injections?
It used to be acceptable for patients to achieve 50% pain relief from diagnostic facet or nerve supply injections. However, numerous studies have shown that there is considerably more reliability in the diagnosis if the patient receives 80% pain relief. Some insurance companies require 80% pain relief on 2 separate occasions prior to approving a radiofrequency ablation.
One recent study in Pain Physician Journal 2009 showed that if the 80% criteria is used, at 2 years time 90% of individuals still continued to have a diagnosis of facet joint pain. With the 50% criteria establishing facet pain, the same study showed only a 51% maintenance of facet joint pain as a diagnosis.
How well do facet joint nerve blocks work? A number of studies have looked at the effectiveness of injections into and around the facet joints. Unfortunately, most of the studies have been small and/or not randomized. This does not mean the results are invalid, rather, the level of evidence is not as strong as what a larger study would bring.
Results for facet joint nerve blocks (medial branch blocks) have been positive, with an average of 80% pain relief lasting between five and seven months. Studies have also shown beneficial results that when the pain relief wears off, repeat injections work well, or the patient can undergo a radiofrequency neurotomy. Patients noted substantial improvements in overall health status, return to work status, functional, and psychological status.
Compared with low back surgery, facet joint nerve blocks are an extremely cost effective, low risk option for pain relief that work.