Botulinum toxin injections to cranial sutures for chronic migraine Rewinding the technique using ultrasound imaging.

The treatment of chronic migraine headache is quite challenging and new alternatives are still being explored for its management. Onabotulinum toxin A (BoNT-A) applied into extracranial muscles has been shown to inhibit the release of acetylcholine and local nociceptive peptides at the sensory nerve endings. As the highest concentration of extracranial pain fibers are located at/nearby the sutures, extracranial applications of BoTN-A are suggested to be performed to sutures rather than into the head and neck muscles in the treatment of chronic migraine. Moreover, in an animal study, BoTN-A is found to be more effective for decreasing the chemosensitivity of meningeal nociceptors when the total dose is injected along the sutures in comparison to being divided into sutures and cranial muscles. Of note, since BoNT-A injections performed with the blind/nontargeted technique have lower effectivity and several complications (muscle weakness, ptosis, facial paresis, etc.), the use of ultrasound guidance for targeting the cranial sutures is definitely expected to provide technical ease, better pain relief and toxin tolerance in chronic migraine.