Analgesic Effects of rTMS in Peripheral Neuropathic Pain

The present multicenter parallel session randomized placebo controlled study (4 French centers) aims to evaluate the long term efficacy over 25 weeks of repeated sessions of magnetic transcranial stimulation of the motor cortex or prefrontal cortex on average pain intensity (primary outcome) and several secondary outcome measures (e.g. quality of life, sleep, neuropathic symptoms, return to work), in patients with peripheral neuropathic pain.

The patients will be randomized to receive one of 3 treatment arms : rTMS of the motor cortex, rTMS of the prefrontal cortex, or placebo (sham stimulation) of the motor or prefrontal cortex. The study will be double blind, eg the patient and the investigator will not know the nature of treatment. the stimulation protocol will consist of an induction phasse of 5 daily sessions then a maintenance phase of several sessions : 3 sessions a week apart, 3 sessions a fortnight apart, and 3 sessions 3 weeks apart. The statistical analysis will be conducted in the intent to treat population and using a modified ITT analysis excluding all the patients with protocol violation (primary outcome). The per protocol population will also be assessed.

Inclusion criteria

• Peripheral neuropathic pain (unilateral or bilateral) probable or defined according to the criteria proposed in 2008 (Treede et al 2008),
• Diagnostic DN4 questionnaire score greater than or equal to 4/10 (Bouhassira et al 2005),
• chronic pain, the average intensity is greater than or equal to 40/100
• Daily or almost daily pain (at least 4 days out of 7)
• This pain is present for more than 6 months
• Patients over 18 and under 75 years old
• Patients who signed informed consent,
• Patients whose pain medication is stable for 15 days before inclusion, and will not need to be changed during the study period,
• Patients who can be monitored during the study period (30 weeks)
• Patients insured by a health insurance plan or entitled.

Exclusion criteria

• Previous treatment using rTMS,
• Work Accident or dispute
• rTMS Cons-indications (ECT treatment during the previous month, epilepsy and / or a history of epilepsy; history of head trauma, neurosurgical lesion, intracranial hypertension, metal clip, pacemaker, pregnant or lactating women)
• Abuse of drugs or psychoactive substances (DSM IV)
• Central neuropathic pain,
• Neuropathic pain within the framework of a progressive disease (HIV, cancer, non-stabilized system disease)
• Neuropathic pain very limited extent, of neuroma type
• Current major depression or psychosis according to DSM IV criteria,
• Intermittent pain,
• Pain for less than six months,
• Presence of another pain more severe than the one justifying the inclusion
• Lack of proper filling of self-assessment of pain from baseline and randomization (at least 4 weekly pain scores 7 days) notebooks
• Lack of stability of pain scores on two successive evaluations, defined as a change of more than 30% between the two assessments of the average pain on the short questionnaire about pain between the first two visits inclusion
• Subject unable to understand informed consent, under guardianship,
• Subject who refuses to stop or can not stop prohibited treatment during the study,
• Patients participating in another research protocol involving a drug within 30 days before enrollment.