Brain opioid receptor density predicts motor cortex stimulation efficacy for chronic pain.

Abstract

The clinical effects of motor cortex stimulation (MCS) for neuropathic pain (NP) is thought to be mediated primarily by the secretion of endogenous opioids in humans and in animal models. Because opioid receptor density is itself decreased in patients with NP, we investigated whether the magnitude and distribution of the remaining opioid receptors in patients with NP could be biological predictors of the pain-relieving effects of MCS. Using (11)C-diprenorphine positron emission tomography scans, opioid receptor availability was assessed in 15 patients suffering refractory NP, who subsequently received chronically implanted MCS. All patients underwent 2 preoperative baseline scans at 2-wk intervals and were clinically assessed after 7mo of chronic MCS. The levels of preoperative opioid-binding in the insula, thalamus, periaqueductal gray, anterior cingulate, and orbitofrontal cortex were significantly and positively correlated with postoperative pain relief at 7mo. Patients with receptor density values below the lower limits in age-matched controls in the thalamus, periaqueductal gray and contralateral insula were the least likely to benefit from MCS. Opioid-receptor availability as shown in preoperative positron emission tomography scans appears to be related to the efficacy of MCS in NP and may help clinicians to select the candidates most likely to benefit from this procedure.

• Authors: Joseph Maarrawi, Roland Peyron, Patrick Mertens, Nicolas Costes, Michel Magnin, Marc Sindou, Bernard Laurent, Luis Garcia-Larrea
• Journal: Pain (Pain) Vol. 154 Issue 11 Pg. 2563-2568 (Nov 2013) ISSN: 1872-6623 [Electronic] United States
• PMID: 23900133 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Chemical References

• Receptors, Opioid

Topics

• Adult
• Aged
• Brain Chemistry (physiology)
• Chronic Pain (diagnostic imaging, physiopathology, therapy)
• Electric Stimulation
• Electrodes, Implanted
• Female
• Humans
• Male
• Middle Aged
• Motor Cortex (physiology)
• Neuralgia (etiology, physiopathology)
• Neuronavigation
• Pain Measurement
• Peripheral Nervous System Diseases (complications)
• Positron-Emission Tomography
• Receptors, Opioid (physiology)
• Reproducibility of Results
• Stroke (complications)