Motor Cortex Stimulation for Neuropathic Pain: A Randomized Cross-over Trial

Area of Science:

• Neuromodulation
• Neurosurgery
• Pain Management

Background:

• Chronic motor cortex stimulation (MCS) has been explored for refractory neuropathic pain over two decades.
• A prospective, multicentre, randomized, blinded, crossover trial was conducted to evaluate MCS efficacy.

Purpose of the Study:

• To assess the effectiveness of motor cortex stimulation (MCS) in treating medically refractory neuropathic pain.
• To compare therapeutic high-dose stimulation versus subtherapeutic low-dose stimulation in pain management.

Main Methods:

• Twelve subjects with neuropathic pain underwent MCS system implantation.
• Participants were randomized to 12 weeks of high or low stimulation, followed by a crossover to the alternative. Primary outcome was the Visual Analogue Scale (VAS) for pain.

Main Results:

• The trial was terminated early due to a lack of efficacy.
• No significant pain reduction (VAS) was observed with either high or low stimulation.
• High stimulation resulted in worse SF-36 physical and mental health scores compared to low stimulation (p=0.024, p=0.005).

Conclusions:

• Motor cortex stimulation (MCS) failed to demonstrate efficacy for refractory upper extremity neuropathic pain.
• Previous positive findings may be attributed to placebo effects, while this study's results might reflect nocebo effects.
• A cautious approach is recommended for considering invasive MCS for upper extremity pain syndromes.