The main objective is to evaluate the analgesic efficacy of botulinum toxin type A in refractory chronic proctalgia one month after a bilateral injection of 50 units of Botox ® in the ganglion Impar (total dose = 100 units)

Inclusion Criteria:

• Age > 18 years
• Patient with chronic proctalgia according to the criteria of Rome III
• Chronic or recurrent rectal pain
• Pains evolve over periods of at least 20 minutes
• With the exclusion of other causes of rectal pain: ischemic, inflammatory bowel disease, cryptic lesions, intramuscular abscess, anal fissure, hemorrhoids, prostatitis and isolated coccydynia
• Pains evolve in a regular way since more than 3 months and the symptoms started since at least 6 months
• These chronic proctalgia include syndromes of anus elevator and nonspecific functional anorectal pains
• Patient with positive anesthetic block of ganglion Impar (minimum of 30 days before D0 and maximum of 270 days before D0)
• Main score (SP) ≥ 4 before infiltration of botulinum toxin type A
• Signed informed consent
• Subjects affiliated with an appropriate social security system

Exclusion Criteria:

• Pain related malignancy
• Patients with bleeding risk and recent anticoagulant therapy
• Surgery within 3 months
• Pre-existing anal incontinence
• Intolerance of botulinum toxin A, local anesthetics and radio contrast medium
• Injection of botulinum toxin in any place whatsoever in the previous 3 months
• Pregnancy and breast feeding
• Antibiotic treatment by aminoglycosides
• Recent anti-inflammatory treatment
• Severe myasthenia
• Lambert-Eaton syndrome
• Patients with neurological disorders, dysphagia, food choking or inhalation pneumonia