Ultrasound-Guided Perisutural Botulinum Toxin Injection for Chronic Migraine Headache: Initial Report With Technical Description

"Prompt" for PREEMPT: Dotting the I's and Crossing the T's With Ultrasound

The management of chronic migraine (CM) underwent a significant shift with the introduction of onabotulinumtoxin A (BoNT-A) injections following the landmark PREEMPT trial in 2010. Despite its efficacy, the existing injection protocol lacks precision, prompting a call for revision in light of modern ultrasound (US)-guided techniques. This article highlights the potential of US-guided injections to enhance accuracy, safety, and efficacy in CM treatment. By providing real-time visualization and addressing anatomical variations, US guidance offers a promising avenue for optimizing BoNT-A delivery, minimizing adverse effects, and ensuring therapeutic success.

The chronicle of headache treatment throughout human history from trepanation to perisutural botulinum toxin injections

To provide a historic snapshot as regards the evolution of headache treatment throughout the human history, i.e. starting from trepanation to perisutural botulinum toxin (BoNT) injections. Ancient surgeons had aimed to reach the cranium with trepanation (a surgical operation) for headache. As BoNT inhibits the release of nociceptive and pro-inflammatory neuropeptides, it has been recently suggested as an effective alternative in the prophylactic treatment of chronic migraine headache. Chronic migraine is a complex neurological disorder for which the underlying pathophysiology is yet not totally explained. According to the generally accepted hypotheses, peripheral neurogenic activation and central trigeminal sensitization are the two main mechanisms through which its pain develops. Since the headache most commonly occurs around the perisutural areas, and as the primary pathogenesis stem from the meningeal nerve fibers; collateral sensorial branches of the meningeal nerves can be optimal paths to transport BoNT inside the cranium. Concerning the therapeutic efficacy, we anticipate that perisutural injections would be technically challenging with blind techniques and actually possible only if performed under an imaging guidance, e.g. very conveniently with high frequency ultrasound.

Sonographic guide for botulinum toxin injections for chronic migraine headache: EURO-MUSCULUS/USPRM approach

Application of botulinum toxin A (BoNT-A) into the muscles of the head and neck area has become a widespread and reliable treatment modality for chronic migraine. The mechanism of action for BoNT-A is the inhibition of acetylcholine and local nociceptive peptide release at the terminal nerve endings. Cranial sutures have the highest concentration of nociceptive structures; therefore BoNT-A injection into the suture lines - as opposed to head and neck muscles - has been proposed for the treatment of chronic migraine. Nerve endings in sutures rapidly absorb BoNT-A and transfer it across the afferent nerve fibers in dura mater via orthodromic and antidromic transmission. In this article, ultrasound-guided BoNT-A application around the cranial sutures will be illustrated. It is noteworthy that suture injections would be safer and more efficient when applied with such guidance.

OnabotulinumtoxinA: Still the Present for Chronic Migraine

OnabotulinumtoxinA (BT-A) is one of the few drugs approved for the preventive treatment of chronic migraine (CM). Despite this, some aspects of its mechanism of action are still a matter of debate, and the precise magnitude of BT-A effects needs to be completely elucidated. BT-A acts primarily upon trigeminal and cervical nerve endings, by inhibiting the release of inflammatory mediators such as calcitonin gene-related peptide, as well as reducing the insertion of ionotropic and metabotropic receptors into the neuronal membrane. These actions increase the depolarization threshold of trigeminal and cervical nerve fibers, thus reducing their activation. The central actions of BT-A are still a matter of debate: a retrograde axonal transport has been postulated, but not clearly assessed in humans. Clinically, the efficacy of BT-A in CM has been assessed by large, randomized placebo-controlled trials, such as the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials. Those results were also confirmed in a wide range of open-label studies, even for long-term periods. Recently, novel findings have led to a better understanding of its pharmacological actions and clinical usefulness in migraine prevention. This narrative review summarizes, updates and critically revises the available data on BT-A and its possible implementation in chronic migraine. Moreover, the current role of BT-A in CM treatment has been discussed.

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.