Inclusion Criteria:
- Persistent Idiopathic Facial Pain fulfilling diagnostic criteria as classified in The International Classification of Headache Disorders, 3rd edition (ICHD-3 beta version) as modified by the authors of this trial. See below.
- Unsatisfactory effect of available treatment methods as evaluated by a neurologist, ENT specialist or maxillofacial surgeon. The patient should have failed treatment with both anticonvulsant as carbamazepine (Tegretol, Carbatrol) and antidepressant as tricyclic antidepressants
- Average Pain intensity ≥4 (0-10) in Numeric Pain Rating Scale (NRS) on the affected side during the 4-week baseline period
- Written informed consent from the patient
Modified diagnostic criteria for PIFP according to The International
Classification of Headache Disorders, 3rd edition (ICHD-3 beta version):
A. Facial and/or oral pain fulfilling criteria B and C.
B. Recurring daily for >2 hr per day for >3 months
C. Pain has both of the following characteristics:
- Poorly localized and may radiate beyond the trigeminal nerve distribution
- Dull, aching or nagging quality D. Clinical neurological examination is normal, however patient may denote paresthesia E. A dental cause has been excluded by appropriate investigations; signs of structural pathology or other specific causes of pain are not identified. Minor operation and injury (insignificant trauma e.g. tooth extraction) to the face, maxilla, teeth and gums without a direct causal relationship with the pain regarding both time and site is accepted. F. Not better accounted for by another ICHD-3 diagnosis.
Exclusion Criteria:
- Bilateral symmetrically affected
- Neurological disorders or other related systemic diseases that can explain the pain
- MRI/CT examination confirming intracranial pathology.
- Systemic or local disease or condition that can give a significantly increased risk of complications to the particular procedure
- Not competent to asses informed consent based on neurological assessment
- Psychiatric disorder that prevents the completion of the study
- Pregnancy
- Inappropriate use of contraception
- Breastfeeding
- Abuse or unauthorized use of medication, drugs or alcohol
- Allergy or other hypersensitivity reactions to marcaine, lidocaine, xylocaine, or adrenaline, possibly similar related drugs
- Anatomical factors that prevent or impede the injection
- Known hypersensitivity to botulinum toxin type A or to any of the excipients
- Treatment with drugs that can interact with botulinum toxin type A: aminoglycoside antibiotics, spectinomycin, neuromuscular blockers, both depolarizing (succinylcholine) and non-depolarizing (tubocurarine derivatives), lincosamides, polymyxins, quinidine, magnesium sulfate, anticholinesterases.