Treating low back pain with combined cerebral and peripheral electrical
stimulation: A randomized, double-blind, factorial clinical trial
Hazime FA, Baptista AF, de
Freitas DG, Monteiro RL, Maretto RL, Hasue RH, João SMA. Eur J Pain. 2017 Apr
25. doi: 10.1002/ejp.1037. [Epub ahead of print]
Take Home Message: While Transcranial Direct-current stimulation (tDCS)
and peripheral electrical stimulation (PES) alone may not provide extended pain
relief, combining the two treatments provided immediate and short-term pain
relief for people with chronic low back pain.
Despite many people having chronic low back pain there is no gold
standard treatment. A possible therapeutic target may be the underlying changes
in the brain related to the onset of chronic pain (for example, grey matter
degradation in pain sensitizations regions). A potential method to target these
changes is transcranial direct-current stimulation (tDCS), which provides a continuous, low current
stimulation to the primary motor cortex to increase excitability and modulate
pain. Efficacy of tDCS is controversial but combining it with other techniques
such as peripheral electrical stimulus (PES) has shown promise. In contrast to
tDCS, PES reduces excitability within the primary sensory and motor cortices
and stimulates other neural sensitization pathways. Combining both therapies may be more efficacious than isolated tDCS
or PES; however, randomized-control trials have yet to be conducted for back
pain. Therefore, investigators conducted a randomized control, double blind,
clinical trial to determine whether combination therapy of tDCS and PES
mitigate chronic low back pain symptoms. Researchers recruited 92 adults with
nonspecific chronic low back pain (>3 months) between 18-60 years old at a
rehabilitation center and local university. Participants were randomized into
four groups that included combination therapy (tDCS + PES), monotherapy of tDCS
or PES, or a sham control for tDCS and PES. The participants received 12 electrical
stimulation sessions over 4 weeks. The researchers assessed pain intensity with
an 11-point numerical rating scale at short-term (4 weeks), medium term (3
months) and long term (6 months) after treatment. Secondary outcomes included
disability and global perception. Immediately after treatment, all 3 treatment
groups had greater pain relief than the group with a sham treatment. However,
there were no differences between treatments. The concurrent therapy of tDCS
and PES was the only technique that maintained analgesic effects after 3 months
(compared with those who received the sham treatment). The analgesic effects
and global perception improvements were lost after 6 months. No treatment
impacted disability or other symptoms at any time point.
This study is important because it highlights that isolated treatments
of tCDS or PES exhibits some effect for immediate nonspecific chronic low back
pain relief but only combination therapy of both techniques provided pain
reduction for medium-term (3 months) relief. The extended pain relief after using
both modalities concurrently may imply a synergistic effect. While synergistic
mechanism is still not understood, the author suggests complementary effects via
concurrent activation of opioid receptors and the release of opioids. While a
passive intervention such as tDCS and PES may fail to provide functional
recovery, the pain-relieving effects they offer may be implemented with other
active therapies. While tDCS and PES are not recommended as primary treatment,
they do seem to provide some effectiveness as adjunct therapy for pain. 
Questions for Discussion:
Do you think concurrent therapy of tDCS and PES has potential to become a
mainstream treatment for chronic pain management for athletes
?
Written by: Cody Criss & Dustin Grooms
Reviewed by: Jeffrey Driban
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