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or who are not candidates for NSAID or opioid therapy. Because of the risk of
excessive sedation, muscle relaxants should not be routinely used in combin-
ation with opioids.
Neck and back pain – mechanical strain 265
Benzodiazepines have skeletal muscle-relaxing properties, and so this
class (most notably diazepam) is occasionally prescribed for MSSP. As is
the case with the muscle relaxants, the benefit of benzodiazepines for
neck and back strain is largely attributable to sedative properties. There are
few studies – none methodologically rigorous – supporting claims that muscle
relaxation is the mechanism by which diazepam mediates pain relief. 14 It is
likely that, at doses commonly prescribed for outpatient treatment, diazepam
produces little or no clinically significant decrease in muscle spasm. Clinicians
who use benzodiazepines for MSSP should be aware that, as is the case with
other muscle relaxants, symptom relief is likely a result of the agents’ sedative
properties.
The manufacturer’s prescribing information for cyclobenzaprine (see US
prescribing information available with the drug) references three unpublished
studies that demonstrate that agent’s superiority over diazepam in
improving patients’ muscle spasm, local pain and tenderness, limitation of
motion, and ability to perform activities of daily living. However, literature
search fails to identify any head-to-head trials in the published literature.
Whetherornotcyclobenzaprine is more effective than diazepam, the
limited data demonstrating benzodiazepine efficacy in MSSP relegate this
class to second-line use. Diazepam should be considered in patients who
fail other therapy, or in those who have responded well to benzodiazepines
in the past.
There is no evidence supporting routine use of systemic corticosteroids in
the acute management of MSSP. 15
Trigger point injection with local anesthetics is occasionally effective for
some patients with neck or back pain, but injection therapy for MSSP has
been insufficiently studied to recommend its routine use. If a patient with
MSSP has a particular trigger point stimulating the pain, injection therapy
may be worthwhile. 16 Facet joint injections of local anesthetics and corticosteroids
are occasionally beneficial, but this procedure is outside the scope of
routine EM practice.