Minimally-invasive procedures such as epidural steroid injections may not be beneficial for patients with symptoms patterns of fibromyalgia, a new study suggests.
The study also found that 42% of patients seeking care for back pain may fit a diagnosis for fibromyalgia, which may explain why they respond poorly to treatments of epidural steroid injections, facet joint injections, and other similar procedures.
Fibromyalgia syndrome (FMS) may damage the capability of the central nervous system to process pain. This process, known as central sensitization, causes patients to have a reduced pain tolerance and hypersensitivity to pain.
Epidural steroid injections, facet joint injections, and medial branch blocks are common treatments for a number of spinal conditions, despite that between 25-45% of patients fail to respond to these treatments. In individuals with chronic pain conditions like fibromyalgia, injections targeting local pain would not be expected to significantly alter centralized CNS pain processing, the researchers suggested. They suspected that high failure rates for spinal injections may be partially related to the presence of central sensitization in a large portion of back-pain patients.
To test this theory, researchers from the University of Michigan studied 443 patients with spinal symptoms such as neck pain, lumbago, and lumbar spinal stenosis. The patients completed several diagnostic questionnaires and were categorized as having fibromyalgia or not based on the 2010 guidelines from the American College of Rheumatology.
A total of 42% met the criteria for having fibromyalgia syndrome. Compared to those who did not meet the FMS criteria, those with FMS were more likely to have depression and anxiety, greater pain severity, pain interference, neuropathic pain descriptors, and poor physical function. They were also more likely to be younger (47 versus 52 years) and unemployed (25% versus 41%), and to be receiving financial compensation. Risk factors for a positive FMS diagnosis included anxiety, physical function, neuropathic pain, and female gender.
Earlier research has demonstrated poor response rates to steroid injections in patients who are younger, depressed, use opioids, or who have a history of chronic symptoms and spinal surgery. Many of these characteristics were found to be common among FMS positive patients. These characteristics, combined with central sensitization, may explain poor response rates to spinal injections among patients with fibromyalgia.
Research suggests that other methods of managing fibromyalgia symptoms, such as exercise, chiropractic care, and cognitive behavioral therapy, may ultimately provide patients with better pain relief. Other recent research has warned against the long-term use of opioids for managing FMS.
 References
Brummett C, et al. Prevalence of the fibromyalgia phenotype in spine pain patients presenting to a tertiary care pain clinic and the potential treatment implications. Arthritis and Rheumatism 2013; DOI: 10.1002/art.38178.
Walsh, N. Spine treatments little help in fibromyalgia. Medpage Today. September 16, 2013. Accessed October 24, 2013. http://www.medpagetoday.com/PainManagement/Fibromyalgia/41626.
