Side effects of facet joint injections

The facet joints are joints that connect the sides of the vertebrae. They are quite important and if they are healthy enough, facet joints provide with stability and give the spine the ability to bend or twist. Similarly to any other joint in the body, the facet joint comprises two surfaces of the adjacent vertebrae and a thin layer of cartilage (which is located between the previously mentioned surfaces). The entire joint is placed into a sac-like capsule filled with synovial fluid.

When are Facet Joint Injections Indicated?

Facet joint injections may be used for diagnosing certain conditions (e.g. identifying the source of back pain) and they are also used for therapeutic purposes.

Facet joint injection is quite effective when it comes to determining whether the facet joint is an actual source of back pain. By injecting a small amount of anesthetic into the facet joint, the doctor checks whether the pain will subside or not. In case the pain alleviates, the facet joint is definitely the source of back pain.

Facet joint injections used for therapeutic purposes include application of certain drugs (anesthetics or anti-inflammatory medications). Such treatment provides with desirable pain relief.

How are these Injections Applied?

Facet joint injections are applied once the patient is given a local anesthetic. This way the communication between the doctor and the patient is preserved. In order to reach the exact site of facet joint, the doctor uses fluoroscope. The treated area is sterilized. What follows is injection of an anesthetic or anti-inflammatory medication into the desirable area. Injection does not last too long ( approximately a few minutes), but together with the preparation the entire procedure may extend to half an hour or even an hour.

As it is the case with any procedure that includes injection of certain medications, even facet joint injections may have some side effects. The most common ones include pain at the injection site, bleeding and infections. Some patients report worsening of back pain after the procedure.

Steroid medications (anti-inflammatory drugs applied by facet joint injections) may trigger facial flushing, low-grade fever, hiccups and insomnia. Additional side effects associated with injection of steroids include headache, water retention, increased appetite, increased heart rate and abdominal cramping or bloating. Fortunately, the previously mentioned side effects are only temporary and withdraw within 1-3 days after the procedure.

The injection of local anaesthetic and/or steroids into the facet joint is being practiced widely throughout the NHS and worldwide as a means of treating patients in whom it is believed the facet joint is the cause of the symptoms of their back pain. However, the effectiveness of this therapy for short- and long-term pain relief requires evaluation, as this has far reaching financial and social consequences.

Lower back pain which originates from the facet joints has not been shown by studies to relate to radiological or pathological changes. The value of plain radiographs, computed tomography and magnetic resonance imaging scans in diagnosing facet joint disease remains inconclusive: degenerative facet joint changes may be seen in asymptomatic patients, and the converse is also true.
Bone scintigraphy with single photon emission computed tomography (SPECT) is more sensitive in detecting facet joint lesions and allows more accurate anatomical localization. A recent study suggested that SPECT could help to identify patients with low back pain who would benefit from facet joint injections.
The advocates of the continuing use of facet joint injections suggest that pain relief in patients following the injection is a diagnostic tool for confirmation of facet joint pathology. However, others insist that both a positive pain provocation response and pain relief are necessary as diagnostic criteria. Furthermore, there is little evidence in any of the available literature that arthrogram is undertaken for confirmation of the correct placement of the needle into the facet joint. Care needs to be taken in order to limit the amount of contrast injected—bearing in mind the facet joint can only hold up to 1-2 mL and that the steroid or local anaesthetic must subsequently be introduced.
Two recent publications by Slipman and van Tulder performed critical analysis of all available literature and found that these injections were not clearly shown to be effective and hence cannot be recommended. These studies reviewed current evidence using the results of systematic reviews within the Cochrane database. This adds further weight to our argument that there is insufficient evidence in support of facet injections.
A systematic review by Boswell et al. suggested that there is moderate evidence (level 3) of an improvement in symptoms following facet injection. Of the studies reviewed by the authors, only Carette et al. performed a double blind, randomized placebo-controlled trial, and this in fact found no short- or long term improvement. In addition, no studies were performed which evaluated cost-effectiveness of therapeutic intra-articular facet joint injections.

An attempt must be made to standardize or limit the influence of confounding variables during periods of long term follow-up (e.g. alternative analgesia, physiotherapy and exercise). Thus, a cost-risk-benefit ratio may be attained and an assessment made of the potential therapeutic use of facet joint injections. Only when the results of such well-designed randomized controlled trials are available can we be sure that the injection of facet joints in the treatment of lower back pain is clinically and financially justifiable.

✓ Fact confirmed: Facet joint injection in lower back pain—is its continued use justified? Saket Tibrewal, Osman H. Khan, and Sheo B. Tibrewal; 2007 Jul

It is essential to know to differentiate the actual side effects of facet joint injections from normal body reaction to the treatment. And finally, it is best if patients abstain from any higher intensity activities and sports for at least 2 weeks after the procedure.