Botulinum toxin treatment of secondary headaches and cranial neuralgias: a review of evidence.

BACKGROUND: Recent scientific data support an effect of botulinum neurotoxin (BoNT) on pain and headache.

OBJECTIVE: We sought to conduct a systematic review of BoNT in the secondary headaches and cranial neuralgias.

METHODS: MEDLINE, EMBASE, Cochrane, ClinicalTrials.gov and reference lists were searched up to December 2010 to identify all relevant publications.

RESULTS: Only two papers were rated as highest evidence (Level 1). The absolute majority (30/38, 79%) of identified publications yield only low evidence (Level 4).

DISCUSSION: No treatment recommendations of Grade A or Grade B can be made based on available research. Grade C treatment recommendations in support of BoNT can be made for chronic headache attributed to whiplash injury, cephalalgic alopecia areata, headache and facial pain in blepharospasm, trigeminal neuralgia, occipital neuralgia and nummular headache. As a result of studies being troublingly inconsistent or inconclusive, only the weakest rank of recommendations (Grade D) can be made for using BoNT in medication overuse headache, cervicogenic headache, headache attributed to craniocervical dystonia, pain in masticatory hyperactivity and headache or facial pain attributed to temporomandibular disorder.

CONCLUSION: At present, BoNT cannot be firmly recommended as an evidence-based treatment in secondary headaches or cranial neuralgias.