Lumbar Facet Joint Injections
- 1 Introduction
- 2 Background
- 3 Procedures
- 4 Effectiveness of Facet Joint Injections
- 5 Conclusions
- 6 References
LBP affects roughly 80% of the UK population and is the 2nd most common cause of long term-sickness from work . A study released in 1999 revealed that the economic burden low back pain (LBP) produces onto the UK economy is £10,668 million, making it the most financially costly condition in the UK . This figure is likely to have risen in recent years due to a larger number of LBP cases becoming chronic .
Spinal injections are one of the many varieties of treatments considered when an individual presents with chronic LBP. As well as a treatment method some spinal injections are also used as a diagnostic tool. An example of one such injection is facet joint injections; which in 2010-2011 made up 36% of all spinal injections (fig. 1.1) .
The effectiveness of facet joint injections is largely unknown but despite this the procedure is still commonly performed by clinicians . The Physiotherapy profession are required to remain up to date with all available procedures each patient has available to them in treating their condition. Consequently, background knowledge regarding this treatment should be known by every clinician who regularly see’s LBP patients. Therefore this Physiopedia page aims to use current literature to shine a light on the main areas surrounding this popular intervention, including:
1. The different procedures used for a facet joint injection
2. The risks facet joint injections cause
3. The variety of conditions that lead to facet joint injections being used
The effectiveness of facet joint injections coupled with some suggestions for future research/Physiopedia pages will be included in the conclusion.
Lumbar Facet Joint
Facet (zyagapophysial) joints are formed of the superior and inferior articulating processes of adjacent vertebra . They are classed as plane synovial joints . Within the Lumbar spine they are orientated in a vertical projection . The articular surfaces are covered by hyaline cartilage, surrounded by a thin fibrous joint capsule that contains a synovial membrane that secretes synovial fluid into the joint space  . Free and encapsulated nerve endings supplied by the medial branches of the dorsi rami, innervate the facet joints .
Facet Joint Injection
Facet joint injections have two main purposes; one to relieve pain both short and long term and the other to be used conjunctively with physical examination as a diagnostic tool to determine whether the facet joint is the source of pain .
The diagram below demonstrates an intra-articular facet joint injection
Diagnostic facet joint injection
The following two-step response pattern are the current gold standard which is used to diagnose facet joint syndrome, which may indicate a need for a therapeutic facet joint injection
1. Saline is injected causing distension of the problematic facet joint - this should reproduce/increase the patients’ pain.
2. Injection of local anaesthetic into the facet joint - this should reduce/relieve the patients’ pain.
Therapeutic facet joint injection
A local anaesthetic is initially given to decrease the nocioceptive signals in and around the facet joint. This is followed by the therapeutic injection which typically contains a mixture of a long acting steroid (e.g. Triamcinolone) and local anaesthesia (e.g. Bupivacaine).
The local anaesthetic will provide immediate pain relief, however the steroids may not start to take effect until 2-6 days post-injection. Pain relief following the injection varies. A study showed that 22%-78% of patients experienced some form of pain relief at 2 weeks. However, long-term relief (3-6 months) varies between 28%-62% of patients, with 38% of patients experiencing no pain relief at 3-months follow-up, increasing to 44% at the 6-month follow-up.
Diagram 3.1 summarising facet injection types and substances
Lumbar Facet Joint Injection Procedure
• The Patient is given the opportunity to ask any questions to relevant doctors
• Sedation is not normally required for the procedure, but some patients can request sedation.
• Consent forms are signed by the patient.
• The patient will be asked to lie in supine whilst a plastic needle cannula will be inserted into the back of the hand.
• The patient will then be asked to lie in prone. The back is cleaned with antiseptic solution and local anaesthetic will be injected into the skin. The patient may experience ‘stinging’ during this stage.
• X- Ray machine will be used during the procedure to help guide and identity the facet joint site.
• When the site is located the local anaesthetic and steroid solution is injected. The patient may also experience increased local pressure resulting in pain.
• The needle will then be removed and a dressing applied to the injection area.
• The patient is then taken to a recovery area where blood pressure is monitored regularly for thirty minutes.
• In normal circumstances the patient is able to return home via escort two hours post procedure. Under no circumstances is the patient allowed to drive home 2 hours post treatment.
Implications for Treatment
Facet injections are general offered as a last resort after failure to improve following a period of conservative treatments, such as physiotherapy, drug therapy, bed rest, chiropractic manipulations and exercise .
These injections might be used in conditions were facet joints may become susceptible to becoming painful such as;
- Lumbar Facet Syndrome
- Ankylosing Spondylitis
- Spinal Stenosis
- Trauma (e.g. road traffic accidents or sports/work with repetitive forceful hyperextensions)
Side effects from the procedure include;
- Localised tenderness
- Pain at the injection site 
- Fainting 
- Paraesthesia (duration few minutes-hours) )
Side effects from the steroids include;
- Fluid retention
- Weight gain
- High blood pressure
- Increase in blood sugar (mainly diabetics) 
- Unexpected allergic reaction to anaesthetic or steroid medication 
- Spondylo discitis, (very rare) occurred in a 78 year old male at L2-L4, this emphasised the importance of proper sterilisation before procedures .
- Septic arthritis 
- Chemical meningism associated with an inadvertent dural puncture
- Excessive Bleeding 
- Transient paraplegia and tetraplegia found in two separate case studies following cervical facet injections without image guidance 
There were no definite contraindications; however this procedure was generally avoided in patients with;
- Systematic infections
- Skin infections over the injection site
- Bleeding disorders (Coagulopathy) or patients taking blood thinning medication
- Allergies to the medication or contrast agents used during the procedure
- Progressive neurological disorders that maybe masked by the procedure
- Pregnancy (due to exposure to radioactive material, eg x-ray)
- Uncontrolled diabetes and heart disease
Effectiveness of Facet Joint Injections
A recent Cochrane review  evaluated lumbar facet injections random controlled trials used in sub-acute (< 6 weeks) and chronic (> 3 months) participants suggested the effectiveness of lumbar facet injections is widely debated. They stated due to a lack of inconsistency between studies in terms of area, drugs, dosage and outcome measures statistical pooling was not possible and as such performed a best-evidence synthesis.
They used 7 random clinical trial studies and found the following
Corticosteriod facet injection vs Placebo;
Based on two studies comparing corticosteroid facet injections with placebos, the short term effects on pain relief and disability maybe not differ from placebos, however intermediate and long term had conflicting results.
Carette et al study showed both the placebo and facet injection group both showed improvement in functional and pain relief at 1, 3 and 6 months, yet statistically differences were only found at 6 months. However the prescript analgesics in addition to these injections might account for improvements in pain relief.
Corticosteriod facet injection vs other treatments;
Based on only 4 Studies found;
When used in conjunction with home exercise programmes no significant differences were found between those who had the injections and those who did not in terms of pain and disability (Mayer 2000 cited ).
The other 3 studies showed no or little significant differences between groups who had corticosteroid injections or ones with a mixture of anaesthetics. None of these studies had controls in addition the injection type, substances and or dosages differed.
The last study gave peri-articular corticosteroid facet injections with or without a local anaesthetic and showed a small difference in reported short term pain relief.
Based on these limited number of studies they concluded the effectiveness of facet injection is still debatable and that more consistent research is needed to draw any conclusions.
Another paper (Lynch and Taylor ) gave 50 participants diagnosed with facet joint pain an intra-articular injection to investigate the short and long term effects on pain perception. They found short term (at 2 weeks) 78% had either total or partial pain relief and long term (at 3 and 6 months) between 56-62% had either total or partial relief. However this study had no control, did not specify whether these participants were receiving any addition treatments during the study and a lack of pain relief might have been due to the solution not being injected into the facet joint but surrounding tissues.
The studies shown suggest these injections maybe no better than placebos, that some patients might benefit from short or long relief while other might not and that these injections might be used in conjunction with other treatments.
Implications for Practice & Research
On conclusion, the evidence on the effectiveness of facet joint injections is inconclusive due to wide variation between studies that limits the number of comparable studies. NICE guidelines (2009)  for LBP and the Cochrane review recommend further comparable research is required into this area before reliable conclusions can be made. Furthermore, research into which demographic groups respond more favourably to injection therapy would be useful to improve the efficiency of this treatment.
Facet joint injections are becoming increasingly more popular in current practice  and therefore it is important every professional treating LBP is aware of the; procedure, risks, implications and their effectiveness. The increasing popularity of this treatment may be due to it being passive compared to the alternatives (exercise programs and postural care) which require the patient to make active changes to their lifestyle. The small amount of literature on whether a facet joint injection is as effective as its alternatives have contrasting conclusions. However it is clear that the literature base is simply not large enough yet to effectively inform practice.
This physiopedia page aimed to give physiotherapy professionals an insight into the basic information surrounding facet joint injections. Alongside this aim was to highlight areas of literature which have not been reviewed, therefore encouraging professionals in the future to create and expand physiopedia pages regarding this large topic, effectiveness and clinical relevance to physiotherapy.
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