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The administration of corticosteroids into the epidural space
to relieve both acute and chronic pain of spinal origin has been
utilized for over 40 years. In 1957 Lievre et al reported the first
use of epidural hydrocortisone for the relief of back pain and sciatica.1 Since
that time numerous investigators have argued both for and against
the efficacy of this technique versus alternative treatment modalities
in providing significant lasting relief for patients suffering from
low back and leg pain. In 1986 Benzon’s review of the literature
on lumbar epidural steroid injections concluded that low back pain
of mechanical origin, especially accompanied by signs of nerve root irritation,
may respond to epidural steroid injection.2 In
1988 Rosen et al, performed a retrospective analysis of the efficacy
of epidural steroid injections, studying 40 patients treated for
low back pain and sciatica secondary to spinal stenosis or lumbar
herniated disc. They concluded that 50% of the patients
with radicular symptoms may receive temporary relief with epidural
steroid injection (ESI); long-term relief, however, occurs in less
then 25% of patients treated.3 In most
studies the principal indications for administering epidural steroid
injections included symptoms of low back pain or leg pain alone
or in combination with varying selection criteria (e.g., previous
surgery, duration of symptoms, patient age).
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Most studies to date have been open trials of varying duration.
There have been several investigations, however, that have attempted
to control the variables that may influence the outcome and subsequently
yield more accurate results regarding the efficacy of ESI. In a
prospective, randomized, double-blind study, Dilke, Burry, and Grahame4 compared
patients whose cause and duration of low back pain and radiculopathy
were similar, received the same steroid medication via epidural
route, and had not been treated previously. They found significantly
better results in the patients receiving steroid; 21 of 35 patients
(60%) compared with 11 of 36 patients (31%) in
the placebo group. At the 3 month follow-up, fewer patients in the
steroid group had severe residual pain (1/44 vs 6/38
patients) and a greater number of patients who received placebo
injections (14 vs 3 patients) were still not working.
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Overall immediate success rates of ESI vary from 25% to
89%,5–7 with long-term results
falling to a mean of 80% by 6 months8 and
56% by 2 years.9 Ryan and Taylor found
that 77% of their patients experiencing symptoms for less
than 2 weeks obtained complete relief from epidural steroid injection,
whereas response rates varied from 72%, 60%, and
43% for patients experiencing pain for 4 weeks, 6 weeks,
and >6 weeks, respectively.6 White
et al found that epidural steroid injections were most effective
in patients with nerve root irritation manifesting as radicular
pain, dermatomal hypesthesia, weakness of muscle groups innervated
by the affected nerve roots, decreased deep tendon reflexes, and
diminished straight leg raise. They noted success rates at 6 months
for 34% of their patients with acute ...