Early Administration of Botox® in Neuropathic Pain Due to Thoracoscopy or Thoracotomy (APTODON)

• VAS in the last 24 hours [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
• Neuropathic Pain Inventory [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Botulinum toxin type A has been reported to inhibit the release of various pain neurotransmitters (SP, CGRP, glutamate) responsible for neurogenic inflammation, a process that results from the sensitization of C-fiber nociceptors (peripheral sensitization). This action is probably responsible for the analgesic effect of botulinum toxin type A recently demonstrated in patients with neuropathic pain of peripheral origin.In those studies, patients had been suffering for years. The investigators can hypothesizes that earlier administration of Botox in the course of neuropathic pain might prevent central sensitization, that is secondary to peripheral sensitization. The investigators can hope to increase efficacy of Botulinum toxin type A injections and to prevent chronification of pain.

• Pain Due to Certain Specified Procedures
• Neuralgia

• Drug: BOTOX
  A syringe of 1 ml contain 25 Allergan units.
• Other: PLACEBO
  The pharmacist will fill syringes in tuberculins of 1 ml with injectable solution of sodium chloride of 0,9 %.

• Experimental: BOTOX
  Patients will receive in one session multiple intradermal injections of Botox, in order to cover the whole painful area
  Intervention: Drug: BOTOX
• Placebo Comparator: PLACEBO
  Patients will receive in one session multiple intradermal injections of placebo , in order to cover the whole painful area
  Intervention: Other: PLACEBO

Inclusion Criteria:

• daily pain, for 3 months, secondary to thoracoscopy or thoracotomy, of neuropathic origin (DN4 questionary)

Exclusion Criteria:

• contraindications for botulinum toxin