Lumbar Facet Joint Injections

Original Editors - Georg Baker, Michelle Harvey, Tommy Pearson, Joe Wakefield as part of the Nottingham University Spinal Rehabilitation Project

Top Contributors - Tommy Pearson, Joe Wakefield, Michelle harvey, Lucinda hampton, Kim Jackson, Laura Ritchie, Admin, Rachael Lowe and George Baker

Introduction

Facet (zygapophyseal) joint injections are performed primarily for the diagnosis and differentiation of facet syndrome and radicular pain syndrome, and are one of the spinal interventional procedures.

• They can be performed under fluoroscopic, or CT image guidance (cervical, thoracic or most commonly lumbosacral facet joints can be injected)
• One or multiple joints can be injected during one procedure.
• Spinal injections are one of the many varieties of treatments considered when an individual presents with chronic LBP .

The effectiveness of facet joint injections is largely unknown but despite this, the procedure is still commonly performed by clinicians .

• Although early studies reported reasonable long term relief of symptoms (20-54%), more recent studies have suggested that steroid injection "is of little value". However, short term relief is common (59-94%) and therefore it remains a useful procedure, especially to confirm the diagnosis.

Lumbar Facet Joints

Lumbar Facet (zygapophysial) joints are formed of the superior and inferior articulating processes of adjacent vertebra .

• Classed as plane synovial joints .
• Orientated in a vertical projection .
• 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 joints have been recognised as a possible source of chronic LBP since the early 1900's .
• Facet joint injections have two main purposes; one to relieve pain both short and long term and the other to be used conjunctively with the physical examination as a diagnostic tool to determine whether the facet joint is the source of pain .
  

1. Diagnostic Facet Joint Injection

The following two-step response pattern is 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.

Diagnostic positive facet joint block can indicate facet joints as the source of chronic spinal pain.

• These patients may benefit from specific interventions to eliminate facet joint pain such as Therapeutic Facet Joint Injection or neurolysis (by radiofrequency or cryoablation)
• Neurolysis is the application of a chemical or physical destructive agent to a nerve to create a long-lasting or permanent interruption of neural transmission.

2. Therapeutic Facet Joint Injection

A local anaesthetic is initially given to decrease the nociceptive 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).

• Early studies reported reasonable long term relief of symptoms (20-54%)
• More recent studies have suggested that steroid injection "is of little value".
• Short term relief is common (59-94%) .

Procedures

Facet joint injections: Minimally-invasive - outpatient procedure can be performed in just a couple hours. The procedure itself usually takes less than 15 minutes.

• To start, patients usually only receive a local anesthetic, but in some cases they may opt for general sedation.
• To begin the procedure, patients will lie face down on the examining table. The area to be injected will be cleaned and numbed with a topical numbing agent before a local anesthetic is administered.
• The doctor inserts a needle using fluoroscopy to ensure proper placement.
• Once the needle is in place, guided also by a fluoroscopic dye, an anesthetic and a steroid will be injected into the facet joint.
• The steroid reduces inflammation and irritation and the anesthetic numbs the pain.
• The combination medicine then spreads to other levels and portions of the spine, reducing inflammation and irritation.
• The needle will then be removed and a dressing applied to the injection area.
• Post-procedure care
  • pain score assessed immediately and 15-20 minutes post-procedure
  • observe for 20 minutes for any immediate complications
  • advise to complete pain diary for the next two weeks
• 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 generally offered following failure to improve from a period of conservative treatments eg physiotherapy, drug therapy, bed rest, and exercise.

• Studies have shown the interval of 6 weeks post-injection, when pain is ideally 80-100% elimintated  physiotherapy treatments (eg land-based lower back mobility exercise, Manual Therapy Techniques For The Lumbar Spine, McKenzie Method) may be of benefit to improve the longer-term outcomes of patients with chronic low back pain.

The following are examples of when injections may be used

1. Lumbar Facet Syndrome: both diagnostic (i.e. relief of pain after injection of local anaesthetic) and therapeutic chronic low back pain.
2. Spondylolisthesis
3. Spondylolysis
4. Ankylosing Spondylitis
5. Spinal Stenosis
6. Trauma (e.g. road traffic accidents or sports/work with repetitive forceful hyperextensions)
7. Low back pain (+/- sciatica) with normal imaging findings
8. Post-laminectomy syndrome

Complications

Rare:

• Infection, including septic arthritis and discitis-osteomyelitis
• Allergic/anaphylactic reaction
• Local reaction to steroid injection (usually >48 hours)
• Bleeding

Contraindications

There were no definite contraindications; however this procedure was generally avoided in patients with;

1. Systematic infections
2. Skin infections over the injection site
3. Bleeding disorders (Coagulopathy) or patients taking blood thinning medication
4. Allergies to the medication or contrast agents used during the procedure
5. Progressive neurological disorders that may be masked by the procedure
6. Pregnancy (due to exposure to radioactive material, eg x-ray)
7. Uncontrolled diabetes and heart disease

Effectiveness of Facet Joint Injections

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. 

A recent Cochrane review evaluated lumbar facet injections random controlled trials used in sub-acute (< 6 weeks) and chronic (> 3 months)

• 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.

NICE guidelines (2009) for LBP recommends

• Further comparable research is required into this area before reliable conclusions can be made (including research into which demographic groups respond more favourably).

Conclusions

Facet joint injections are becoming increasingly more popular in current practice

• 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.
• It is clear that the literature base is simply not large enough yet to effectively inform practice.