Jan Van Zundert, Vissers K,
Facet joints, also called zygapophyseal joints, are articulations of the posterior arch of the vertebrae; they are true synovial joints. They provide structural stability and allow flexion and extension movements. Osteoarthritis is characterized by loss of joint space, loss of synovial fluid, cartilage damage, and shrinking and bony overgrowth. Pain originating from the lumbar facet joint has a reported prevalence from less than 5% to 90%, a variation that is attributed to differences in diagnostic criteria. Studies performed in well-selected patient populations report a range between 5% and 15% of the population with axial low back pain.1 The diagnostic process consists of history taking, clinical examination, and medical imaging. The patient reports localized unilateral or bi-lateral low back pain potentially with referral into the buttock and upper thigh. The pain is aggravated by unilateral pressure and pain on extension, lateral flexion, and rotation. Paravertebral tenderness is found with clinical examination. Medical imaging shows degenerative facet joints, although there is little correlation with the pain. Positive response to a medial branch or intra-articular injection with local anesthetic is used to confirm the causative level.1
Conservative treatment consists of manual therapy, exercise, and rehabilitation. Non-steroidal anti-inflammatory drugs can be used at the lowest effective dose and for the shortest period possible. Routine use of opioids and paracetamol (acetaminophen) as only medication is not recommended.2 There is no place for antidepressants and anti-epileptic drugs.
Intra-articular corticosteroid injections were compared with a variety of treatments. No difference between treatments could be demonstrated. The added value of corticosteroid added to local anesthetic could not be demonstrated. Most studies report pain reduction for 3 to 6 months in about half of the patients.
Radiofrequency treatment of the ramus medialis of the lumbar ramus dorsalis was studied in RCTs show a positive result if the diagnosis was correctly made. Looking closer at two of the RCTs indicates that a diagnostic block at the ramus medialis of the ramus dorsalis evaluated in the day care center 1 hour after administration was positive in 31% of the patients. The RF treatment resulted in an NNT of 1.6.3 For the second RCT the diagnostic block was performed intra-articularly and the assessment was done by the family doctor during the 24 hours following injection. Ninety-two percent of the patients were judged to have a positive block, the NNT was 11.4 To improve the accuracy, the use of controlled blocks has been proposed. An RCT analysed the outcome of RF treatment after no, one, or two diagnostic blocks. The best result was obtained in the groups who had two positive blocks, because there are fewer false positives but also more false negatives.
A recently published RCT comparing facet joint denervation plus standard exercise treatment with exercise treatment alone shows several methodological flaws, resulting in the inclusion of 72.3% of the patients. Moreover, 3 months after inclusion patients who were randomized to the exercise group could receive RF treatment when the pain reduction was not satisfactory. At 3 months 24.6% of the patients crossed over to RF treatment in addition to the 9.5% who already received RF treatment in the first 3 months. The statistical analysis was based on a linear mixed-effects regression model that includes not only the 3-month measurement, but all measures over the 12-month follow-up. By taking all measures after 3 months into account, the effect of cross-over after 3 months was extrapolated to the first three months. When comparing the baseline with the 3-month pain score there is a 2.13-point improvement in pain intensity versus 1.65 points in the exercise group.5 This study triggered several comments in the international literature.6,7 A large retrospective chart analysis showed an incidence of 1.0% minor complications.8
The NICE guidelines2 recommend ‘Consider referral for assessment for radiofrequency denervation for people with chronic low back pain.’ [Based on moderate to very low-quality evidence from randomized controlled trials, a cost effectiveness analysis, and the experience and opinion of the GDG.]
The management of low back pain potentially originating from the facet joints requires confirmation of the diagnosis based on the history, the clinical examination, and diagnostic imaging illustrating degeneration. Patients are preferentially treated conservatively, taking into consideration that the use of NSAIDs and opioids should be limited in dose and duration (as low as possible, as short as possible) because of the potentially serious side effects, complications, and addiction for the latter. Attention should be paid to the presence of yellow flags that give an indication for the risk to progress towards chronicity. When conservative treatment fails, identification of the causative level with a diagnostic block can, if positive, be followed by radiofrequency treatment of the ramus medialis of the ramus dorsalis.
- van Kleef M, Vanelderen P, Cohen SP, Lataster A, Van Zundert J, Mekhail N. 12. Pain originating from the lumbar facet joints. Pain Pract. 2010;10:459-69.
- Bernstein IA, Malik Q, Carville S, Ward S. Low back pain and sciatica: summary of NICE guidance. BMJ. 2017;356:i6748.
- van Kleef M, Barendse GA, Kessels A, et al. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine (Phila Pa 1976). 1999;24:1937-42.
- Leclaire R, Fortin L, Lambert R, Bergeron YM, Rossignol M. Radiofrequency facet joint denervation in the treatment of low back pain: a placebo-controlled clinical trial to assess efficacy. Spine. 2001;26:1411-6; discussion 1417.
- Juch JNS, Maas ET, Ostelo R, et al. Effect of Radiofrequency Denervation on Pain Intensity Among Patients With Chronic Low Back Pain: The Mint Randomized Clinical Trials. JAMA. 2017;318:68-81.
- Kapural L, Provenzano D, Narouze S. RE: Juch JNS, et al. Effect of Radiofrequency Denervation on Pain Intensity Among Patients With Chronic Low Back Pain: The Mint Randomized Clinical Trials. JAMA 2017;318(1):68-81. Neuromodulation. 2017;20:844.
- Provenzano DA, Buvanendran A, de Leon-Casasola OA, et al. Interpreting the MINT Randomized Trials Evaluating Radiofrequency Ablation for Lumbar Facet and Sacroiliac Joint Pain: A Call From ASRA for Better Education, Study Design, and Performance. Reg Anesth Pain Med. 2017;43:68-71.
- Kornick C, Kramarich SS, Lamer TJ, Todd Sitzman B. Complications of lumbar facet radiofrequency denervation. Spine. 2004;29:1352