Treatment of chronic neuropathic pain by motor cortex stimulation: Results of a bicentric controlled crossover trial

Nguyen, Jean-Paul; Velasco, Francisco; Brugières, Pierre; Velasco, Marcos; Keravel, Yves; Boleaga, Bernardo; Brito, Francisco; Lefaucheur, Jean-Pascal

doi:10.1016/j.brs.2008.03.007

« Previous Next »BRAIN STIMULATION: Basic, Translational, and Clinical Research in Neuromodulation
Volume 1, Issue 2 , Pages 89-96, April 2008

Treatment of chronic neuropathic pain by motor cortex stimulation: Results of a bicentric controlled crossover trial

Jean-Paul Nguyen, MD
- Service de Neurochirurgie, Hôpital Henri Mondor, Assistance Publique–Hôpitaux de Paris, Créteil, France
Francisco Velasco, MD
- Department of Stereotactic and Functional Neurosurgery, General Hospital of Mexico, and Department of Medical Research in Neurophysiology, National Medical Center, Mexico City, Mexico
Pierre Brugières, MD
- Service de Neuroradiologie, Hôpital Henri Mondor, Assistance Publique–Hôpitaux de Paris, Créteil, France
Marcos Velasco, MD, PhD
- Department of Stereotactic and Functional Neurosurgery, General Hospital of Mexico, and Department of Medical Research in Neurophysiology, National Medical Center, Mexico City, Mexico
Yves Keravel, MD
- Service de Neurochirurgie, Hôpital Henri Mondor, Assistance Publique–Hôpitaux de Paris, Créteil, France
Bernardo Boleaga, MD
- Department of Magnetic Resonance Imaging, Clinica Londres, Mexico City, Mexico
Francisco Brito, MD
- Department of Stereotactic and Functional Neurosurgery, General Hospital of Mexico, and Department of Medical Research in Neurophysiology, National Medical Center, Mexico City, Mexico
Jean-Pascal Lefaucheur, MD, PhD
- Service de Physiologie-Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique–Hôpitaux de Paris, Créteil, France
- Address reprint requests to: Prof. Jean-Pascal Lefaucheur, Prof. Jean-Paul Nguyen, Service de Physiologie, Service de Neurochirurgie, Hôpital Henri Mondor, 51 avenue de Lattre de Tassigny, 94010 Créteil, France.

Received 17 February 2008; accepted 3 March 2008. published online 12 May 2008.

Background

Chronic motor cortex stimulation (MCS) with surgically implanted epidural electrodes has been proposed as a treatment for neuropathic pain refractory compared with medical treatment. However, no prospective controlled trial has been published to provide convincing evidence of MCS analgesic efficacy.

Objective

To compare MCS analgesic efficacy between “ON”- and “OFF”-stimulation conditions in a double-blinded crossover trial.

Methods

Ten patients with chronic neuropathic pain of either peripheral or central origin underwent MCS implantation in two centers (Créteil, France, and Mexico City, Mexico). At the end of the second postoperative month, patients were randomly assigned into two groups. In the first group, the stimulator was switched “OFF” for two weeks and then was switched “ON” for the next 2 weeks. The opposite sequence was applied in the second group. Preoperative and postoperative assessment (until 1 year after surgery) was performed using visual analogue scale (VAS), verbal scale (VS), Wisconsin brief pain questionnaire (WBPQ), McGill pain questionnaire (MPQ), McGill quality of life scale, and medication quantification scale.

Results

During the crossover trial, VAS, VS, WBPQ, and MPQ scores were significantly reduced in the“ON”- compared with the “OFF”-stimulation condition. One year after surgery, all clinical scores were significantly reduced compared with preoperative values. In particular, MCS decreased the affective MPQ subscore relative to the sensory MPQ subscore. Six of the 10 patients clearly benefited from MCS treatment.

Conclusions

These results were in favor of real analgesic effects produced by MCS with no loss of benefit over time. The differential changes in MPQ subscores suggested that MCS relieved pain by acting predominantly on its affective aspect. The decrease in pain intensity was associated with improved daily living activities and quality of life and reduced consumption of analgesic medication.

Keywords: crossover trial, functional neurosurgery, McGill pain questionnaire, motor cortex stimulation, neuropathic pain, prospective trial