Osteoarthritis is the most common form of arthritis that occurs as the musculoskeletal system ages. As the joint cartilage thins, the increasing pressures on the joints results in bone spur formation (osteophytes) and increasing irritation to the nerves that supply sensation to the joint structures. The apophyseal or facet joints guide movement in the lumbar spine. They are not weight-bearing joints. However, as intervertebral discs thin over time, increasing pressures are placed of these facet joints. The facet or apophyseal joints are the structures that develop osteoarthritis. Similar to what is seen in osteoarthritis of the knee or hip, weighting the joints (standing up) causes increasing pain in the lumbar spine or low back
In many circumstances non-pharmacological therapy –(exercise, weight reduction, for example) is very effective in decreasing pain and improving function. Pharmacological therapy also has a useful role including nonsteroidal anti-inflammatory drugs and agents that increase tone in the pain inhibitory pathway in the central nervous system, like duloxetine. Although the vast majority of chronic low back pain patients have their facet joint pain controlled, a minority remain with persistent pain.
Injection therapy is thought to be an effective therapy for individuals with persistent low back pain related to facet joint osteoarthritis. Nerves from adjacent levels of the lumbar spine supply sensation to the facet joints. As opposed to intraarticular injections given for knee osteoarthritis, periarticular injections of the numbing medicine affecting the facet nerves is more effective. Once it is established that analgesic injections of the facet joint nerves is effective in controlling low back pain, ablation techniques are considered to deaden the nerves by freezing them (cryotherapy) or heating (radiofrequency denervation) them is thought to be appropriate.
Dr. Lee and colleagues completed an analysis of all available and appropriate studies of conventional radiofrequency denervation.1 Adult patients undergoing radiofrequency denervation or control treatments (sham or epidural block) for facet joint disease of the lumbar spine were among those eligible for the analysis. In their analysis 454 patients were included where 231 underwent the radiofrequency ablation procedure. At 1-year follow-up, the denervation group exhibited significantly greater improvements than the controls in back pain in visual analogue scale scores. A subgroup of patients who responded very well to diagnostic block procedures demonstrated significant improvement compared to controls at all times during the trial.
Although not all reports have clearly demonstrated the benefit of radiofrequency denervation the procedure definitely benefits some individuals.2 What appears to be important for a good outcome, is the response to diagnostic blocks that identify the facet joints causing chronic low back pain. Denervation of the specifically offending facet joints has the best opportunity for a patient with decreased chronic low back pain.
David Borenstein, M.D.
Executive editor TheSpineCommunity
1. Lee C et al: The efficacy of conventional radiofrequency denervation in patients with chronic low back pain originating from the facet joints: a meta-analysis of randomized controlled trials. Spine J 2017;17:1770-80