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Three Part Question

In [adult patients presenting with isolated traumatic rib fractures] are [topical lignocaine patches] effective [in reducing pain and opiate analgesic use]?

Clinical Scenario

A 76 year old man presents to the Emergency Department with multiple rib fractures after falling down stairs. His pain is difficult to manage, despite intravenous opioids. You speak to the acute pain team for advice on how to manage his pain. They suggest using 5% lignocaine patches over the site of maximal pain.

Search Strategy

Medline 1946 to November week 4 2013: (exp lidocaine OR lignocaine patch OR lidocaine patch AND rib fractures.

Embase via NHS evidence 1980 to November 26 3013: (exp lidocaine OR lidocaine patch OR lignocaine patch AND rib fracture)

Cochrane Database of Systematic Reviews
(exp lidocaine OR lignocaine patch OR lidocaine patch AND rib fractures)

Search Outcome

10 papers identified using medline search
38 papers identified using Embase search
No reviews identified using Cochrane Database of Systematic Reviews

2 papers were relevant to the clinical question

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Zink et al, 2011 USA	58 patients presenting to the hospital’s trauma system, emergency room, or clinics with rib fractures receiving lignocaine patches (29) identified through pharmacy records, or matched control subjects not recieving lidocaine patches (29).	Observational study. Prospective cohort of patients were retrospectively analysed for use of lignocaine patches. They were matched to control subjects treated without patches.	Primary end point: change in subjective pain scores in first 24 hours after patch placement. Relevant secondary end points: change in opiate use in first 24 hours.	Primary: In the 24 hours after patch placement, lignocaine patch (LP) patients had a greater decrease in pain scores (LP 1.2 vs controls 0.0, p=0.01). Secondary: No significant change in opiate use (LP -8.4mg vs controls 0.5mg change in morphine dose, p=0.25).	Observational study, partly retrospective with unblinded and subjective primary outcome assessment. Potential confounders: 1) Large difference in pain scores and opiate use between the 2 groups before patch placement therefore not truly matched controls. 2) Injury severity scores were high in both groups (21) suggesting the presence of other significant injuries. Low numbers in subgroup analysis with isolated chest injury (9 lignocaine patch vs 8 controls) therefore no significant difference found in primary outcome. 3) In lignocaine patch group a greater proportion of patients had more fractures, flail chest, chest drain placement and epidurals (although not significant due to overall low study numbers). 4) Epidurals – some treated with lignocaine patches after epidurals whilst some had both treatments synchronously Potential bias: 1) Unblinded outcome assessment 2) Assessment of pain scores - subjective scores used in patients who were aware they had patches applied
Ingalls et al 2010 USA	58 patients with rib fractures admitted to a Level 1 trauma centre receiving either lignocaine patch 5% (33) or placebo patch (25)	Randomized, double-blind, placebo-controlled trial	Primary – total (IV and oral) opiate use. Relevant secondary outcomes – non-opiate pain medication and average visual analogue pain score	Primary: No significant difference in total IV opiate used; median 0.23 units (IQR 0.07-1.02) in lignocaine group vs median 0.26 units (IQR 0.08-0.59) in placebo group (p=0.56). No significant difference in total oral opiate use; median 4 units (IQR 2-10) in lignocaine group vs 7 units (IQR 2.5-14) in placebo group (p=0.11). Secondary: Mean pain scores (+/-SEM) 5.6+/- 0.4 in lignocaine group vs. 6.0+/- 0.3 in placebo group (p=0.39).	Study powered to detect a reduction of 33% in pain scores which is quite ambitious. Study too small and underpowered to show statistically significant difference between the 2 groups. But, there was a trend towards improved pain scores in the lignocaine patch group. Pain scores were collected by nursing staff over 72hours and averaged to a single pain score for the study period. Patients were only followed up for 72 hours. Theses were all trauma patients with other injuries. However, the other injuries were not listed. Patients were given an Injury severity score (17.3 in lignocaine group and 17.9 in placebo group) which may suggest significant other/distracting injury. Conflict of interest: study sponsored by the drug company

Comment(s)

Rib fractures are one of the most injuries presenting to the Emergency Department. The pain associated with these fractures is often difficult to manage. Lignocaine patches have been shown to be effective and safe in the treatment of other pain, such as postherpatic neuralgia. Although not licensed for use in the treatment of rib fractures, many centres are using them anecdotally for this reason, at potentially significant costs to health services. These papers are of limited value due to small numbers and weaknesses in their methodology. Patients included in the studies were polytrauma patients with the presence of other significant injuries, therefore we cannot comment on the effect of lignocaine patches on pain control and opiate use in isolated rib injuries.

Clinical Bottom Line

Currently, there is no evidence to support the use of topical lignocaine patches to improve pain control and reduce opiate analgesic use, in patients with traumatic rib fractures. A prospectively designed trial with a large cohort of appropriately selected patients is needed to evaluate the use of lignocaine patches in this patient group.

References

1. Zink KA, Mayberry J, Peck E, et al. Lidocaine Patches Reduce Pain in Trauma Patients with Rib Fractures. Am Surg 2011; 77: 438-442.
2. Ingalls NK, Horton ZA, Bettendorf M, et al Randomized, double-blind, placebo-controlled trial using lidocaine patch 5% in traumatic rib fractures. J Am Coll Surg 2010; 2: 205-9.