Original articleInterventional neurophysiology for pain control: duration of pain relief following repetitive transcranial magnetic stimulation of the motor cortexNeurophysiologie interventionnelle dans le contrôle de la douleur : la durée du soulagement de la douleur après la stimulation magnétique transcranienne répétitive du cortex moteur.
Section snippets
Patients and methods
The study included 14 right-handed patients, eight females and six males, aged 34 to 80 years (mean 57.2 years). None had history of seizures. The patients presented chronic, drug-resistant, unilateral pain and were referred to our hospital to be treated by implanted motor cortex stimulation. The pain was due to a thalamic stroke (infarction or haemorrhage) (n = 7) or a trigeminal neuropathy (with past history of surgery in the trigeminal territory or thermocoagulation of the trigeminal
Results
No adverse effects of rTMS were observed immediately after the session or the days after; in particular no seizures were induced.
Figure 1 presents the mean daily VAS scores following ‘real’ and ‘sham’ 10Hz-rTMS session in the entire series of 14 patients. A significant reduction of the daily VAS scores was found from days 1 to 8 after ‘real’ 10Hz-rTMS session compared to ‘sham’ stimulation (P-values ranged between 0.013 and 0.049). From days 9 to 12, the difference between the two conditions
Discussion
This study shows for the first time that pain relief could last about a week after 10Hz-rTMS of the motor cortex in patients suffering chronic neurogenic pain of various origins. However, definitive conclusions could not be made considering separately the two types of pathologies assessed in this study, i.e. thalamic stroke and trigeminal neuropathy, due to the too small number of patients in each subgroup.
The lowest pain scores were observed between 2 and 4 days following the rTMS session, and
Acknowledgements
The authors are indebted to Isabelle Menard and Richard Morales for their technical assistance. The work was supported by a grant from the ‘Institut UPSA de la douleur’.
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