Spinal Injections

Published on 18/03/2015 by admin

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Last modified 18/03/2015

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Section 5 Spinal Injections

Spinal injection guidelines

We strongly recommend that clinicians wishing to give spinal injections attend recognized training courses and undergo a period of supervised practice with an experienced colleague before attempting them on their own.

Overview

Low back pain without disc herniation is the most common problem among chronic pain disorders, but a patho-anatomical cause can be established in only 15 % of all cases.1 Treatments to relieve this affliction have been many, among them spinal injections – engendering much controversy in the literature; opinions about efficacy, safety and relevance have differed greatly since their inception in the 1920s, with many studies considered poor quality.217

Although epidural injections are one of the most commonly used invasive interventions in the treatment of low back pain, with or without radicular pain, there is currently little consensus about this technique and wide variation in practice.21 There is also no agreement on the most effective approach for lumbar epidural injection, whether to use steroid, local anaesthetic, saline or a combination, or the exact volume required. Depot steroids are not licensed for spinal use18,19 but orthopaedic and pain specialists, rheumatologists and others use these injections extensively.20 The caudal route of administration may require a larger volume but is least likely to cause dural puncture.22,23

A paucity of well designed, randomized controlled studies, and a lack of statistically significant results in the existing literature mean that a solid foundation for the effectiveness of spinal injection therapy is lacking.9 NICE, the UK National Institute for Health and Clinical Excellence, recommended that patients with persistent non-specific low back pain should not be offered injections of therapeutic substances,24 but what impact this has had on clinical practice is uncertain.

A Cochrane Review found minor side-effects such as headache, dizziness, transient local pain, tingling, numbness and nausea reported in a small number of patients in only half the trials reviewed. The review 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.10

Safety

All the contraindications listed in Section 2 apply, but particularly:

The incidence of intravascular uptake during lumbar spinal injection procedures is approximately 8.5%; it is greater in patients over 50, and if the caudal route is used rises to 11%. Absence of flashback of blood on pre-injection aspiration does not predict extravascular needle placement.31 Epidural steroid injection is safe in patients receiving aspirin-like antiplatelet medications, with no excess risk of serious haemorrhagic complications, i.e. spinal haematoma. Increased age, large needle gauge, needle approach, insertion at multiple interspaces, number of needle passes, large volume of injectant and accidental dural puncture are all relative risk factors for minor haemorrhagic complications.32

Safety precautions and strict aseptic techniques are the same as for all injections. An additional hazard is the rare possibility of an intrathecal injection of local anaesthetic which may be avoided by using corticosteroid alone. The rationale is that the benefit of the brief relief of pain and the diagnostic information obtained from using an anaesthetic does not outweigh the potential risks. Normal saline can be added or Adcortyl used instead of Kenalog if additional volume is required.

New neurological symptoms or worsening of pre-existing complaints that persist for more than 24 hours (median duration of symptoms 3 days, range 1–20 days) might occur after epidural injection,32 but in the authors’ experience this is rare.

The British Society for Rheumatology and the Royal College of Anaesthetists produce guidelines for the use of epidural injections. We commend them to all practitioners who give these injections. They can be found at:

Efficacy

Lumber epidurals: a systematic review of epidural corticosteroids for back pain found at least 75% pain relief in the short term (1–60 days) with the number needed to treat (NNT) of 7 (7–16) and at least 50% pain relief in the long term (3–12 months) with NNT of 13 (7–314).3 A randomized, double-blind, controlled trial concluded that lumbar interlaminar epidural of local anaesthetic with steroid was effective in 86% of patients, and without steroid in 74%.31

A systematic review indicated positive evidence (Level II-2) for short-term relief of pain from disc herniation or radiculitis utilizing blind interlaminar epidural steroid injections; there was less strong evidence for long-term pain relief for these conditions and for the short- and long-term relief of pain from spinal stenosis and from discogenic pain without radiculitis or disc herniation.25 Another review of both caudal and lumbar epidurals also concluded that the best studies showed inconsistent results and benefits were of short duration only.6 Yet another showed strong evidence for epidurals in the management of nerve root pain due to disc prolapse, but limited evidence in spinal stenosis.22 A multicentre randomized controlled trial of epidurals for sciatica reported significant relief at 3 weeks but no long-term benefit.14

In the past, large volumes have been injected into the epidural space;33 however, a total injection volume of 8 ml is sufficient for a caudal epidural injection to reach the L4/5 level.34

Selective guided nerve-root injections of corticosteroids are significantly more effective than those of bupivacaine alone in obviating the need for operative decompression for 13–28 months following the injections in operative candidates. This finding suggests that patients who have lumbar radicular pain at one or two levels should be considered for treatment with selective nerve-root injections of corticosteroids prior to operative intervention. A significantly greater proportion of patients treated with transforaminal injection of steroid achieve relief of pain compared with those treated by transforaminal injection of local anesthetic or saline or intramuscular steroids.30 When symptoms have been present for more than 12 months, local anaesthetic alone may be just as effective as steroid and local anaesthetic together.

When conservative measures fail, nerve-root injections are effective in reducing radicular pain in patients with osteoporotic vertebral fractures and no evidence of nerve root palsy. These patients may be considered for this treatment before percutaneous vertebroplasty or operative intervention is attempted.35,36,38

Injection of the sacroiliac joints for painful sacroiliitis appears to be safe and effective. It can be considered in patients with contraindications or complications with NSAIDs, or if other medical treatment is ineffective,37 though often manipulative techniques can obviate the need for an injection. However, accurate placement of the drug without the use of fluoroscopy is estimated to be successful in only 12 % of patients.40

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