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Three Part Question

[In patients with chronic simple low back pain] are [facet joint injections better than standard rehabilitation] at [decreasing pain and improving function]

Clinical Scenario

A 55 year old woman represents to her general practitioner with back pain of 3 years duration. Previous assessments and investigations have not suggested a serious cause of her back pain but it so severe that she has had to give up work and has become depressed. She attends as she has rad on the internet that the joints of the back can be injected and that this can relieve her pain. She asks you if this is true and if so could you refer her for the treatment.

Search Strategy

Medline 1966 - June 2005. OVID via ATHENS.
[low back pain.mp. or exp Low Back Pain/ or back pain.mp. or exp Back Pain/ or lumbar pain.mp.] and [zygapophysial.mp. or exp Zygapophyseal Joint/ or facet joint.mp.] limit to humans and english language and abstracts.

Search Outcome

Medline. 221 papers were found. One recent high quality systematic review was identified that searched up to 2002. In addition a trial published in 2005 was identified. These two articles are shown below.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Shih C et al 2005 Taiwan	277 patients with simple chronic low back pain. Affected joints were assessed on clinical examination criteria. The affected and contiguous joints were injected with lidocaine and betamethasone. Patients were followed up until 12 weeks. Patients with a good intial result were considered to have facet joint pain and were compared against a control of patients with a poor intial response (whom the authors assumed did not have facet joint pain)	Observational study	Good response in treatment group	72.1% at 3 weeks, 40,7% at 6 weeks and 31.4% at 12 weeks. No data given on the control group.	Many weaknesses in this paper. Of particular, no initial screening to confirm that the facet joints were the source of the patients pain. The post treatment allocation of cases to controls makes little sense. Incomplete data recording. 28.9 % of patients also had radiofrequency ablation.
Slipman et al 2003 USA	Clinical trials of zygapophysial joint injections for patients with chronic back pain	Systematic review (without meta-analysis)	Number of papers found	11 papers found, but only 4 were prospective trials, and only one used diagnostic injections to confirm that facet joints were the cause of the pain.	Unclear the exact dates of searching, but implication is that they searched up to 2002.
			Effect of injections	Only 1/4 studies showed an effect. The only high quality study showed no effect.

Comment(s)

Facet joint injections are a commonly advocated therapy for patients with chronic low back pain. The evidence presented here suggests that there is little current evidence from high quality trials. The single high quality study included in the systematic review by Carette (1) is the only one to definatively diagnose facet joints as a source of the patients pain. Without confirmation it is perhaps not surprising that the other studies had less convincing results. Recent texts which do advocate the use of facet joint injections state the importance of confirming the diagnosis in patients through the use of diagnostic screening blocks (2). 1. Carette S, Marcoux S, Truchon R et al. A controlled trial of corticosteroid injections into the facet jointsfor chronic low back pain. N Eng J Med 1991;325:1002-1007 2. Medical Management of acute and chronic back pain: An evidence based approach. Bogduk N, McGuirck B. Elsevier. 2002. Amsterdam.

Clinical Bottom Line

There is little published evidence from clinical trials to support the use of lumbar facet joint injections in chronic back pain. They should only ever be considered in patients with confirmed facet joint pain from diagnostic injections.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Shih C, Lin GY,Yueh KC, Lin JJ. Lumbar zygapophyseal joint injections in patients with chronic back pain. J Chin Med Assoc 2005;68:59-64
2. Slipman CW, Bhat AL, Gilchrist RV, Issac Z, Chou L, Lenrow DA. A critical review of the evidence for the use of zygapophysial injections and radiofequency denervation in the treatment of low back pain. The Spine Journal 2003;3:310-316