In the European Journal of Pain Supplements, 19 juli 2010 Garcia–Larrea discussed the value of Motor cortex stimulation (MCS), a relatively recent neurosurgical technique for pain control, in the treatment fo neuropathic pain. This is an abstract of a talk he gave at the  Third International Congress on Neuropathic Pain in Athens earlier this year. We were there and would like to make some commets, as this talk was discussed in great detail by a MD from the UK. She stated that there has not been conducted one methodological acceptable clinical trial analysing the safety and efficacy of this technique.

Motor cortex stimulation: placebo effects or more?

The presentator stated that clinical series show that at least 50% of patients with chronic, pharmacoresistant neuropathic pain may benefit from this technique.^[1] However, the critic was that this technique has an ultra high placebo response, as it is invasive AND the physician is a neurosurgeon, one of the highest ranked individuals of the medical stairs, just below GOD in the perception of many people. All these series were open, and provide no data whatsoever about the biological effects of the invention. 

Garcia–Larrea pointed out that we think that MCS may act through at least two mechanisms: activation of perigenual cingulate and orbitofrontal areas may modulate the emotional appraisal of pain, rather than its intensity, while top down activation of brainstem PAG may lead to descending inhibition toward the spinal cord. Especially the first mechanism of action could be counted for by placebo effects.

Just as the fact that an other mechanism could be  the possible secretion of endogenous opioids triggered by chronic MCS.

Reasons enough to be cautious and wait till double blind studies are available.

Jan M. Keppel Hesselink, MD, PhD, juli 2010 

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