Cannabis Sprays Reduced Nerve Pain from Brachial Plexus Injury
A randomized trial found that cannabis-based sprays (Sativex and THC-only) produced statistically significant pain improvements in 48 patients with brachial plexus nerve pain, though the improvements did not meet the predefined two-point clinical significance threshold.
Quick Facts
What This Study Found
In 48 patients with chronic nerve pain from brachial plexus root avulsion, both Sativex (THC:CBD approximately 1:1) and a THC-only extract delivered by oral spray produced statistically significant improvements in pain severity compared to placebo during two-week treatment periods. Sleep measures also improved significantly.
However, the primary outcome (mean pain severity over the last 7 days) did not fall by the two points defined in the study hypothesis as clinically meaningful, placing this in the category of statistically significant but not clinically significant by the researchers' own predefined standard. The medications were generally well tolerated, with most adverse events being mild to moderate.
Key Numbers
Forty-eight patients enrolled. Baseline pain score 4+ on 11-point scale. Two-week treatment periods. Both active treatments showed statistically significant improvement. Predefined two-point clinical significance threshold not met.
How They Did This
This was a randomized, double-blind, placebo-controlled, three-period crossover study. Forty-eight patients with at least one avulsed brachial plexus root and baseline pain score of 4+ (out of 11) received placebo, Sativex (THC:CBD), or THC-only extract via oromucosal spray in random order, each for two weeks following a two-week baseline.
Why This Research Matters
Brachial plexus avulsion pain is an excellent model of central neuropathic pain because the injury is anatomically uniform. All patients had intractable symptoms on current analgesics, making this a treatment-resistant population. The finding of statistical significance despite the predefined clinical threshold not being met raised important questions about outcome definition in chronic pain research.
The Bigger Picture
This trial contributed to the evidence base for Sativex in neuropathic pain. While the primary outcome was technically not met, the combination of statistical significance, sleep improvement, and good tolerability in a treatment-resistant population supported continued development. Sativex was later approved for MS-related neuropathic pain in some jurisdictions.
What This Study Doesn't Tell Us
Two-week treatment periods may have been too short for full therapeutic effect in chronic pain. The predefined two-point threshold for clinical significance was ambitious for a pain population already on analgesics. The crossover design could be affected by carryover effects.
Questions This Raises
- ?Would longer treatment periods produce larger pain improvements?
- ?Was the two-point threshold too stringent for treatment-resistant neuropathic pain?
- ?How do these results compare to other treatments for brachial plexus pain?
Trust & Context
- Key Stat:
- Statistically significant pain and sleep improvement in treatment-resistant nerve pain
- Evidence Grade:
- This is a well-designed randomized, double-blind, placebo-controlled crossover trial with 48 patients, providing moderate-level evidence.
- Study Age:
- Published in 2004. Sativex was subsequently approved for neuropathic pain in some jurisdictions.
- Original Title:
- Efficacy of two cannabis based medicinal extracts for relief of central neuropathic pain from brachial plexus avulsion: results of a randomised controlled trial.
- Published In:
- Pain, 112(3), 299-306 (2004)
- Authors:
- Berman, Jonathan S, Symonds, Catherine, Birch, Rolfe
- Database ID:
- RTHC-00157
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Can cannabis help with nerve pain?
This trial found statistically significant improvements in neuropathic pain from brachial plexus injury with cannabis-based sprays. While the improvement was modest, it was meaningful for patients who had not responded to other pain treatments.
What is the difference between statistical and clinical significance?
Statistical significance means the result was unlikely due to chance. Clinical significance means the improvement is large enough to matter to patients. This trial achieved the former but not the latter by the researchers' own predefined standard of a two-point reduction on an 11-point scale.
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Cite This Study
https://rethinkthc.com/research/RTHC-00157APA
Berman, Jonathan S; Symonds, Catherine; Birch, Rolfe. (2004). Efficacy of two cannabis based medicinal extracts for relief of central neuropathic pain from brachial plexus avulsion: results of a randomised controlled trial.. Pain, 112(3), 299-306. https://doi.org/10.1016/j.pain.2004.09.013
MLA
Berman, Jonathan S, et al. "Efficacy of two cannabis based medicinal extracts for relief of central neuropathic pain from brachial plexus avulsion: results of a randomised controlled trial.." Pain, 2004. https://doi.org/10.1016/j.pain.2004.09.013
RethinkTHC
RethinkTHC Research Database. "Efficacy of two cannabis based medicinal extracts for relief..." RTHC-00157. Retrieved from https://rethinkthc.com/research/berman-2004-efficacy-of-two-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.