Injection therapy is one of many treatments available for patients with subacute (longer than six weeks) and chronic (longer than 12 weeks) low-back pain. Where the injection is given, what drug is used and why the injection is given can all vary. The injection can be given into different parts of the spine (the space between the vertebrae, around the nerve roots, or into the disc), ligaments, muscles or trigger points (spots in the muscles that when pressed firmly will produce pain). Drugs that reduce swelling (corticosteroids, non-steroidal anti-inflammatory (NSAIDs)) and pain (morphine, anaesthetics) are used. Injection therapy can be used for individuals with low-back pain with or without pain and other symptoms in the leg.
A number of electronic databases of healthcare articles were searched up to March 2007. This search identified 18 randomized controlled trials (RCTs; 1179 participants) that looked at injections with a variety of drugs compared to a placebo drug or other drugs. The injections were given into the epidural space (between the vertebrae of the back and outside the coverings that surround the spinal cord), the facet joints (the joints of two vertebrae), or tender spots in the ligaments or muscles. The review authors rated ten of the 18 RCTs as having a low risk of bias in the way the trials were conducted and reported. They were unable to statistically pool the results because the injection sites, drugs used and outcomes measured were too varied. Only five of the 18 trials reported significant results in favor of one of the treatment arms.
The reviewer authors considered the likely treatment benefits to be worth the potential harms in only two studies. In nine out of the 18 studies, side effects such as headache, dizziness, transient local pain, tingling and numbness and nausea were reported in small numbers of patients. The use of morphine was more frequently associated with itching, nausea and vomiting. Rare but more serious complications of injection therapy have been mentioned in the literature, such as cauda equina syndrome, septic facet joint arthritis, discitis, paraplegia, paraspinal abscesses. Although the absolute frequency of these complications may be rare, these risks should be taken into consideration. Based on these results, the review authors concluded that there is no strong evidence for or against the use of any type of injection therapy for individuals with subacute or chronic low-back pain. (Staal J Bart, de Bie Rob, de Vet Henrica CW, Hildebrandt Jan, Nelemans Patty TI: Injection therapy for subacute and chronic low-back pain. Cochrane Database of Systematic Reviews: Reviews 2008 Issue 3 John Wiley & Sons, Ltd Chichester, UK).
This following study was performed to (1) investigate the clinical effectiveness of epidural steroid injections in the treatment of sciatica with an adequately powered study and to identify potential predictors of response to epidural steroid injections. (2) To investigate the safety and cost-effectiveness of lumbar epidural steroid injections in patients with sciatica.
DESIGN: A pragmatic, prospective, multicentre, double-blind, randomised, placebo-controlled trial with 12-month follow-up was performed. Patients were stratified according to acute (<4 months since onset) versus chronic (4-18 months) presentation. All analyses were performed on an intention-to-treat basis with last observation carried forward used to impute missing data.
SETTING: Rheumatology, orthopaedic and pain clinics in four participating centres: three district hospitals and one teaching hospital in the south of England.
PARTICIPANTS: Total of 228 patients listed for epidural steroid injection with clinically diagnosed unilateral sciatica, aged between 18 and 70 years, who had a duration of symptoms between 4 weeks and 18 months.
INTERVENTIONS: Patients received up to three injections of epidural steroid and local anaesthetic (active), or an injection of normal saline into the interspinous ligament (placebo).
MAIN OUTCOME MEASURES: The primary outcome measure was the Oswestry Disability Questionnaire; measures of pain relief and psychological and physical function were collected. Health economic data on return to work, analgesia use and other interventions were also measured. Quality-adjusted life-years were calculated using the SF-6D, calculated from the Short Form (SF-36). Costs per patient were derived from figures supplied by the centers' finance departments and a costings exercise performed as part of the study. A cost-utility analysis was performed using the SF-36 to calculate costs per Quality-adjusted life-years.
RESULTS: Epidural steroid injections led to a transient benefit in Oswestry Disability Questionnaire and pain relief, compared with placebo at 3 weeks (p = 0.017, number needed to treat = 11.4). There was no benefit over placebo between weeks 6 and 52. Using incremental Quality-adjusted life-years, this equates to and additional 2.2 days of full health. Acute sciatica seemed to respond no differently to chronic sciatica. There were no significant differences in any other indices, including objective tests of function, return to work or need for surgery at any time-points. There were no clinical predictors of response, although the trial lacked sufficient power to be confident of this. Adverse events were uncommon, with no difference between groups.
Costs per Quality-adjusted life-years to providers under the trial protocol were 44,701 pounds sterling. Costs to the purchaser per Quality-adjusted life-years were 354,171 pounds sterling. If only one epidural steroid injection was provided then costs per Quality-adjusted life-years fell to 25,745 pounds sterling to the provider and 167,145 pounds sterling to the purchaser. Epidural steroid injections thus failed the Quality-adjusted life-years threshold recommended by the National Institute for Health and Clinical Excellence (NICE).
CONCLUSIONS: Although epidural steroid injections appear relatively safe, it was found that they confer only transient benefit in symptoms and self-reported function in a small group of patients with sciatica at substantial costs. Epidural steroid injections do not provide good value for money if NICE recommendations are followed.
Additional research is suggested into the epidemiology of radicular pain, producing a register of all epidural steroid injections, possible subgroups who may benefit from epidural steroid injections, the use of radiological imaging, optimal early interventions, analgesic agents and nerve root injections, the use of cognitive behavioural therapy in rehabilitation, improved methods of assessment, a comparative cost-utility analysis between various treatment strategies, and methods to reduce the effect of scarring and inflammation. (Price C, Arden N, Coglan L, Rogers PTI: Cost-effectiveness and safety of epidural steroids in the management of sciatica. Pain Clinic, Royal South Hants Hospital, Southampton, UK, 2005).