Acute treatment of intractable migraine with sphenopalatine ganglion electrical stimulation

Rationale and Design for the BLOCK-SAH Study (Pterygopalatine Fossa Block as an Opioid-Sparing Treatment for Acute Headache in Aneurysmal Subarachnoid Hemorrhage): A Phase II, Multicenter, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial with a Sequential Parallel Comparison Design

BACKGROUND

Acute post-subarachnoid hemorrhage (SAH) headaches are common and severe. Management strategies for post-SAH headaches are limited, with heavy reliance on opioids, and pain control is overall poor. Pterygopalatine fossa (PPF) nerve blocks have shown promising results in treatment of acute headache, including our preliminary and published experience with PPF-blocks for refractory post-SAH headache during hospitalization. The BLOCK-SAH trial was designed to assess the efficacy and safety of bilateral PPF-blocks in awake patients with severe headaches from aneurysmal SAH who require opioids for pain control and are able to verbalize pain scores.

METHODS

BLOCK-SAH is a phase II, multicenter, randomized, double-blinded, placebo-controlled clinical trial using the sequential parallel comparison design (SPCD), followed by an open-label phase.

RESULTS

Across 12 sites in the United States, 195 eligible study participants will be randomized into three groups to receive bilateral active or placebo PPF-injections for 2 consecutive days with periprocedural monitoring of intracranial arterial mean flow velocities with transcranial Doppler, according to SPCD (group 1: active block followed by placebo; group 2: placebo followed by active block; group 3: placebo followed by placebo). PPF-injections will be delivered under ultrasound guidance and will comprise 5-mL injectates of 20 mg of ropivacaine plus 4 mg of dexamethasone (active PPF-block) or saline solution (placebo PPF-injection).

CONCLUSIONS

The trial has a primary efficacy end point (oral morphine equivalent/day use within 24 h after each PPF-injection), a primary safety end point (incidence of radiographic vasospasm at 48 h from first PPF-injection), and a primary tolerability end point (rate of acceptance of second PPF-injection following the first PPF-injection). BLOCK-SAH will inform the design of a phase III trial to establish the efficacy of PPF-block, accounting for different headache phenotypes.

Open label experience of repeated OnabotulinumtoxinA injections towards the sphenopalatine ganglion in patients with chronic cluster headache and chronic migraine

BACKGROUND

A novel technique for injection of OnabotulinumtoxinA (BTA) towards the sphenopalatine ganglion (SPG) has shown promise in refractory chronic migraine (CM) and chronic cluster headache (CCH). Open label safety and efficacy data are presented here.

METHODS

Patients with refractory CM or CCH who had received at least one injection and completed headache diaries were included. Efficacy was defined as ≥50% reduction in moderate-to-severe headache days for CM, or ≥50% reduction in attack frequency for CCH, at weeks five to eight.

RESULTS

Over 261 injections, there were 123 adverse events (AE), of which one was serious. Most (93%) AEs were mild and all were transient. The 50% response to one injection was 81% for CM and 69% for CCH. The response gradually reduced over subsequent months for CM but stayed between 55% and 67% for CCH. Repeated injections were beneficial.

CONCLUSIONS

Injections resulted in improvement for both groups and was maintained with repeated injections. Repeat injection after three months may be beneficial in CM. Adverse events were not uncommon, but universally transient, presumably as a result of the mechanism of action of BTA. Repeated BTA injection towards the SPG could be an effective treatment for refractory CM and CCH. Larger, randomised, placebo-controlled trials are required.

Neuromodulation for Craniofacial Pain and Headaches

Headaches and facial pain are highly prevalent diseases but are often difficult to treat. Though there have been significant advances in medical management, many continue to suffer from refractory pain. Neuromodulation has been gaining interest for its therapeutic purposes in many chronic pain conditions, including headaches and facial pain. There are many potential targets of neuromodulation for headache and facial pain, and some have more robust evidence in favor of their use than others. Despite the need for more high-quality research, the available evidence for the use of neuromodulation in treating headaches and facial pain is promising. Considering the suffering that afflicts patients with intractable headache, neuromodulation may be an appropriate tool to improve not only pain but also disability and quality of life.

Neuromodulation for the Sphenopalatine Ganglion-a Narrative Review

PURPOSE OF REVIEW

To provide an integrated overview of the current state of knowledge of neuromodulation for the sphenopalatine ganglion (SPG) by reviewing relevant and significant literature.

RECENT FINDINGS

There are several case reports and clinical trials evaluating neuromodulation for the SPG. We identified two blinded, randomized clinical trials for patients with chronic cluster headache. The randomized trials and additional studies demonstrated the long-term safety, efficacy, and cost-effectiveness of neuromodulation for the SPG. Recent studies in Europe and the USA suggest that SPG neuromodulation is a novel modality with clinical importance for treating acute cluster headaches and reducing the frequency of attacks.

Symptoms and pathophysiology of cluster headache. Approach to combined occipital and supraorbital neurostimulation

Cluster headache (CH) is included under section 3 - Trigeminal autonomic cephalalgias (TAC) of the International Headache Society (IHS) classification. It is one of the most frequent, painful and disabling primary headaches. Acute and preventive pharmacological treatments are often poorly tolerated and of limited effectiveness. Due to improved understanding of the pathophysiology of CH, neuromodulation devices are now considered safe and effective options for preventive and acute treatment of CH. In this paper, we review the information available to date, and present the case of a patient with disabling cluster headache highly resistant to medical treatment who underwent implantation of a peripheral nerve neurostimulation system to stimulate the supraorbital nerves (SON) and greater occipital nerve (GON) in our Pain Unit. We also review the diagnostic criteria for CH, the state of the knowledge on the pathophysiology of CH, and the role played by neuromodulation in treating this condition.

Comparison of Peripheral Neurectomy vs. Medical Treatment for Migraine: A Randomized Controlled Trial

Background

Migraine is a common form of primary neurologic headache. Many patients are chronic migraineurs and suffer from a significant disability and adverse effects of drugs. There are various surgical options available to treat migraines, including peripheral neurectomies.

Objective

To study the surgical and functional outcomes of migraine surgeries using peripheral neurectomies and compare them with conservatively treated patients.

Materials and Methods

Migraine patients who had a unilateral onset pain were given local bupivacaine block at the suspected trigger site, and those who were relieved were given the option for surgery. In the operative group, the peripheral nerve of the trigger site was lysed under local anesthesia. The conservative group was continued with the standard treatment. Evaluations with a baseline and 6 months visual analog score (VAS), migraine headache index (MHI), migraine disability assessment test (MIDAS), and pain self-efficacy questionnaire (PSEQ) scores were done.

Results

A total of 26 patients got benefitted with the local bupivacaine block, out of which 13 underwent surgery. At baseline, the VAS, MHI, MIDAS, and PSEQ scores were similar in both the groups. The operative group had significant (P < 0.001) improvement in all these parameters 6 months after the surgery. All patients of the operative group got free from prophylactic migraine treatment; however, 11 out of 13 patients still needed occasional  use of analgesics. There was one complication of transient temporal numbness.

Conclusion

Migraine surgery using peripheral neurectomies was more effective than chronic drug treatment in appropriately selected patients.

Electrical Characterization of the Tongue and the Soft Palate Using Lumped-Element Model for Intraoral Neuromodulation

Intraoral functions are results of complex and well-orchestrated sensorimotor loop operations, and therefore vulnerable to small functional or neural defects. To secure the vital intraoral functions, it is important to find a way to favorably intervene the intraoral sensorimotor loop operations. The tongue and the soft palate are heavily associated with intraoral sensorimotor loops, with their dense neural innervations and occupancy of intraoral space. Therefore, electrical stimulation onto the tongue and the soft palate has a great potential to solve the problems in the intraoral functions. However, the electrical interface for both of them have not been characterized yet as a lumped-element model, for designing electrical stimulation and analyzing its effect. In this study, we measured stimulation thresholds to evoke electrotactile feedback and characterized electrical impedance across electrodes using lumped-element models. We found that average perception/discomfort thresholds for the tongue tip, lateral-inferior side of the tongue, and anterolateral side of the soft palate as 0.18/1.31, 0.37/3.99, and 1.19/7.55 mA, respectively. An R-C-R-R-C model represented the electrical interface across the tongue and the soft palate with the highest accuracy. The average component values of the R-C-R-R-C model were found as 2.72kΩ, 45.25nF, 1.27kΩ, 22.09GΩ, and 53.00nF, on average.

Cortical and subcortical changes following sphenopalatine ganglion blocks in chronic migraine with medication overuse headache: a preliminary longitudinal study

Objective

The purpose of this pilot study was to investigate potential changes in brain morphology (cortical thickness and cortical/subcortical volume) accompanying a series of sphenopalatine ganglion (SPG) blockade treatments in chronic migraine with medication overuse headaches (CM^w/MOH).

Background

Local anesthetization of the SPG via intranasal application is used for the treatment for multiple types of headache disorders, including CM. Our previous longitudinal fMRI study revealed improved network connectivity after such treatment. However, the impact of SPG blocks on cortical, subcortical gray matter volume and cortical thickness has yet to be assessed.

Methods

Using magnetic resonance imaging (MRI), cortical/subcortical volume were measured in 12 chronic migraine patients before and after a series of 12 SPG blocks administered over a 6-week period (2 per week). The average time between MRI assessments was 6 weeks. Targeted, within-subjects t-tests comparing pre-treatment and post-treatment values in specific apriori brain regions of interest, including the hippocampus, amygdala, basal ganglia, somatosensory cortex, temporal cortex and occipital cortex, were used to estimate the impact of repetitive SPG blocks treatment on brain morphology in CM^w/MOH.

Results

Compared to baseline values, the number of moderate/severe headache days per month, HIT-6, PHQ-9 scores and allodynia scores were all significantly improved at the end of treatment. Analysis of MRI data revealed that the volume of the right hippocampus and the right palladium significantly decreased following SPG block treatment, while the volume of the left nucleus accumbens significantly increased following treatment. Cortical thickness in the left temporal pole and left lateral occipito-temporal gyrus significantly decreased following SPG block treatment.

Conclusion

Our results suggest SPG block treatment is associated with significant symptom improvement as well as significant structural brain changes in regions known to be associated with migraine and chronic pain processing in CM^w/MOH.

Low frequency activation of the sphenopalatine ganglion does not induce migraine-like attacks in migraine patients

Introduction

Cephalic autonomic symptoms occur in 27‒73% of migraine patients during attacks. The role of parasympathetic activation in migraine attack initiation remains elusive. Low frequency stimulation of the sphenopalatine ganglion increases parasympathetic outflow. In this study, we hypothesized that low frequency stimulation of the sphenopalatine ganglion would provoke migraine-like attacks in migraine patients.

Methods

In a double-blind randomized sham-controlled crossover study, 12 migraine patients with a sphenopalatine ganglion neurostimulator received low frequency or sham stimulation for 30 min on two separate days. We recorded headache characteristics, cephalic autonomic symptoms, ipsilateral mechanical perception and pain thresholds, mean blood flow velocity in the middle cerebral artery (VMCA) and diameter of the superficial temporal artery during and after stimulation.

Results

Five patients (42%) reported a migraine-like attack after low frequency stimulation compared to six patients (50%) after sham ( p = 1.000). We found a significant increase in mechanical detection thresholds during low frequency stimulation compared to baseline ( p = 0.007). Occurrence of cephalic autonomic symptoms and changes in mechanical perception thresholds, VMCA and diameter of the superficial temporal artery showed no difference between low frequency stimulation compared to sham ( p = 0.533).

Conclusion

Low frequency stimulation of the sphenopalatine ganglion did not induce migraine-like attacks or autonomic symptoms in migraine patients. These data suggest that increased parasympathetic outflow by the sphenopalatine ganglion neurostimulator does not initiate migraine-like attacks. Study protocol: ClinicalTrials.gov registration number NCT02510742

Localization of the Sphenopalatine Ganglion Within the Pterygopalatine Fossa on Computed Tomography Angiography-A Potential Role in the Setting of Sphenopalatine Ganglion Microstimulator Implantation

OBJECTIVES

A recent approach to treatment of cluster headaches (CH) employs a microstimulator device for on-demand neuromodulation of the sphenopalatine ganglion (SPG) during an acute CH attack. A precise anatomical localization of the SPG within the pterygopalatine fossa (PPF) is optimal in order to position the SPG electrode array. This study aims to investigate a novel approach for SPG localization using computed tomography angiographic studies (CTA).

MATERIALS AND METHODS

Two independent observers identified the location of the SPG on 54 computed tomography angiographic studies (CTA) and measured its position relative to the vidian canal (VC). The qualitative confidence of identification, morphology, position within the PPF and its relation to vascular structures were also recorded.

RESULTS

The SPG was detectable in 88% of cases with a variable position. The most frequent positions were superior (56%) and lateral (99%) relative to the VC with a mean (±SD) craniocaudal distance of 0.34 mm (±1.38) and a mean mediolateral distance of 3.04 mm (±1.2). However, in a considerable proportion of cases, the SPG was identified inferiorly to the VC (33%). Interobserver and intraobserver agreement for SPG location were moderate and strong respectively.

CONCLUSIONS

Since localization of SPG on CTAs is feasible and reproducible, it has future clinical potential to aid placement, optimal positioning and individualized programming of the electrode array.

The Evolution of Neuromodulation in the Treatment of Chronic Pain: Forward-Looking Perspectives

Background

The field of neuromodulation is continually evolving, with the past decade showing significant advancement in the therapeutic efficacy of neuromodulation procedures. The continued evolution of neuromodulation technology brings with it the promise of addressing the needs of both patients and physicians, as current technology improves and clinical applications expand.

Design

This review highlights the current state of the art of neuromodulation for treating chronic pain, describes key areas of development including stimulation patterns and neural targets, expanding indications and applications, feedback-controlled systems, noninvasive approaches, and biomarkers for neuromodulation and technology miniaturization.

Results and Conclusions

The field of neuromodulation is undergoing a renaissance of technology development with potential for profoundly improving the care of chronic pain patients. New and emerging targets like the dorsal root ganglion, as well as high-frequency and patterned stimulation methodologies such as burst stimulation, are paving the way for better clinical outcomes. As we look forward to the future, neural sensing, novel target-specific stimulation patterns, and approaches combining neuromodulation therapies are likely to significantly impact how neuromodulation is used. Moreover, select biomarkers may influence and guide the use of neuromodulation and help objectively demonstrate efficacy and outcomes.

Efficacy of electrical stimulation for treatment of migraine

BACKGROUND

The objective of this study is to assess the efficacy of electrical stimulation (ES) for the treatment of patients with migraine.

METHODS

MEDLINE, EMBASE, Cochrane Library, CINAHL, PsycINFO, Scopus, Web of Science, Allied and Complementary Medicine Database, ProQuest Nursing and Allied Health, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure will be searched for eligible studies. All electronic databases will be searched from inception to the present with no language restriction. Two authors will independently carry out study selection, data collection, and study quality assessment, respectively. RevMan 5. 3 software will be used for statistical analysis.

RESULTS

This study will summarize high quality evidence on the efficacy and safety of ES for the treatment of migraine.

CONCLUSION

This study will establish the accurate results of ES for migraine to facilitate the clinical practice and guideline development.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019147480.

Migraine: Experimental Models and Novel Therapeutic Approaches

Migraine is a disorder affecting an increasing number of subjects. Currently, this disorder is not entirely understood, and limited therapeutic solutions are available. Migraine manifests as a debilitating headache associated with an altered sensory perception that may compromise the quality of life. Animal models have been developed using chemical, physical or genetic modifications, to evoke migraine-like hallmarks for the identification of novel molecules for the treatment of migraine. In this context, experimental models based on the use of chemicals as nitroglycerin or inflammatory soup were extensively used to mimic the acute state and the chronicity of the disorder. This manuscript is aimed to provide an overview of murine models used to investigate migraine pathophysiology. Pharmacological targets as 5-HT and calcitonin gene-related peptide (CGRP) receptors were evaluated for their relevance in the development of migraine therapeutics. Drug delivery systems using nanoparticles may be helpful for the enhancement of the brain targeting and bioavailability of anti-migraine drugs as triptans. In conclusion, the progresses in migraine management have been reached with the development of emerging agonists of 5-HT receptors and novel antagonists of CGRP receptors. The nanoformulations may represent a future perspective in which already known anti-migraine drugs showed to better exert their therapeutic effects.

Expression Analysis of Serotonin Receptors, Serotonin Transporter and l-Amino Acid Decarboxylase in the Mouse Sphenopalatine Ganglion by RT-PCR, Northern Blot Analysis and In Situ Hybridization

The sphenopalatine ganglion (SPG) is a gathering of the cell bodies of parasympathetic fibers that dominate the nasal gland, lacrimal gland and cerebral blood vessels. The SPG controls nasal secretions, tears, and the dilation of cerebral blood vessels. However, it is unclear how serotonin regulates SPG functions. In this study, we investigated the expression of genes involved in the serotonergic system in the mouse SPG. We examined the mRNA expression levels of 5-HT_1A, 5-HT_1B, 5-HT_1D, 5-HT_1F, 5-HT_2A, 5-HT_2B, 5-HT_2C, 5-HT_3A, 5-HT_3B, 5-HT₄, 5-HT_5A, 5-HT_5B, 5-HT₆ and 5-HT₇ receptors, as well as serotonin transporter, tryptophan hydroxylases 1 and 2, and L-amino acid decarboxylase (AADC) by RT-PCR. It revealed that the 5-HT_3A and 5-HT_3B ionotropic receptors and AADC were likely to be highly expressed in the SPG, as measured by RT-PCR. We next performed in situ hybridization on the SPG to examine the expression of these three genes at the cellular level after validating the specificity of each cRNA probe by northern blotting. The 5-HT_3A receptor, 5-HT_3B receptor, and AADC were expressed in 96.5% ± 1.0%, 29.7% ± 10.7%, and 57.4% ± 2.9% of neuronal cell bodies in the SPG, respectively, indicating that the 5-HT_3A receptor was virtually expressed in all SPG neurons. Our results on the expression of these critical serotonin system genes in the parasympathetic SPG provide insight into the pathogenetics of rhinitis, conjunctivitis and headache. Furthermore, our findings suggest that targeting the 5-HT_3A receptor might have therapeutic potential in the treatment of these ailments.

Vidian Neurectomy for Management of Chronic Cluster Headache

BACKGROUND

Management of chronic cluster headache (CCH) remains a challenging endeavor, and the optimal surgical approach for medically refractory CCH remains controversial.

OBJECTIVE

To conduct a preliminary evaluation of the efficacy and safety of vidian neurectomy (VN) in patients with medically refractory CCH.

METHODS

Between March 2013 and December 2015, 9 CCH patients, all of whom had failed to respond to conservative therapy, underwent VN with a precise nerve cut and maximal preservation of the sphenopalatine ganglion. Data included demographic variables, cluster headache onset and duration, mean attack frequency, mean attack intensity, and pain disability index measures pre- and through 12-mo postsurgery.

RESULTS

Seven of the 9 cases (77.8%) showed immediate improvement. Improvement was delayed by 1 mo in 1 patient, after which the surgical effects of pain relief were maintained throughout the follow-up period. One patient (11.1%) did not improve after surgery. One year after VN, patients' mean attack frequency, mean attack intensity, and pain disability index decreased by 54.5%, 52.9%, and 56.4%, respectively. No patient experienced treatment-related side effects or complications.

CONCLUSION

VN is an effective treatment method for CCH patients. Precise Vidian nerve identification and maximal preservation of the sphenopalatine ganglion may achieve good surgical outcomes and dramatically improve quality of life among patients, without significant adverse events.

Neurostimulation for the treatment of chronic migraine and cluster headache

Small subsets of patients who fail to respond to pharmacological treatment may benefit from alternative treatment methods. In the last decade, neurostimulation is being explored as a potential treatment option for the patients with chronic, severely disabling refractory primary headaches. To alleviate pain, specific nerves and brain areas have been stimulated, and various methods have been explored: deep brain stimulation, occipital nerve stimulation, and sphenopalatine ganglion stimulation are among the more invasive ones, whereas transcranial magnetic stimulation and supraorbital nerve stimulation are noninvasive. Vagal nerve stimulation can be invasive or noninvasive, though this review included only data for noninvasive VNS. Most of these methods have been tested in small open-label patient series; recently, more data from randomized, controlled, and blinded studies are available. Although neurostimulation treatments have demonstrated good efficacy in many studies, it still has not been established as a standard treatment in refractory patients. This review analyzes the available evidence regarding efficacy and safety of different neurostimulation modalities for the treatment of chronic migraine and cluster headache.

Migraine and cluster headache - the common link

Although clinically distinguishable, migraine and cluster headache share prominent features such as unilateral pain, common pharmacological triggers such glyceryl trinitrate, histamine, calcitonin gene-related peptide (CGRP) and response to triptans and neuromodulation. Recent data also suggest efficacy of anti CGRP monoclonal antibodies in both migraine and cluster headache. While exact mechanisms behind both disorders remain to be fully understood, the trigeminovascular system represents one possible common pathophysiological pathway and network of both disorders. Here, we review past and current literature shedding light on similarities and differences in phenotype, heritability, pathophysiology, imaging findings and treatment options of migraine and cluster headache. A continued focus on their shared pathophysiological pathways may be important in paving future treatment avenues that could benefit both migraine and cluster headache patients.

The Effect of Regional Anesthetic Sphenopalatine Ganglion Block on Self-Reported Pain in Patients With Status Migrainosus

BACKGROUND

Status migrainosus (SM) is defined as a debilitating migraine attack lasting more than 72 hours in patients previously known to suffer from migraine headache. Typically, these attacks fail to respond to over the counter and abortive medications. The sphenopalatine ganglion (SPG) plays a critical role in propagating both pain and the autonomic symptoms commonly associated with migraines. SPG block via transnasal lidocaine is moderately effective in reducing migraine symptoms, but this approach is often poorly tolerated and the results are inconsistent. We proposed that an SPG block using a suprazygomatic injection approach would be a safe and effective option to abort or alleviate pain and autonomic symptoms of SM.

METHODS

Through a retrospective records review, we identified patients with a well-established diagnosis of migraine, based on the International Headache Society criteria. Patients selected for study inclusion were diagnosed with SM, had failed to respond to 2 or more abortive medications, and had received a suprazygomatic SPG block. Patients had also been asked to rate their pain on a 1-10 Likert scale, both before and 30 minutes after the injection.

RESULTS

Eighty-eight consecutive patients (20 men and 68 women) received a total of 252 suprazygomatic SPG block procedures in the outpatient headache clinic after traditional medications failed to abort their SM. At 30 minutes following the injections, there was a 67.2% (±26.6%) reduction in pain severity with a median reduction of 5 points (IQR= -6 to -3) on the Likert scale (ranging from 1 to 10). Overall, patients experienced a statistically significant reduction in pain severity (P < .0001).

CONCLUSION

The SPG is known to play an integral role in the pathophysiology of facial pain and the trigeminal autonomic cephalalgias, although its exact role in the generation and maintenance of migraine headache remains unclear. Regional anesthetic suprazygomatic SPG block is potentially effective for immediate relief of SM. We believe the procedure is simple to perform and has minimal risk.

Non-Pharmacological Approaches for Migraine

Migraine is one of the most common and debilitating neurological disorders. However, the efficacy of pharmacological therapies may have unsatisfactory efficacy and can be poorly tolerated. There is a strong need in clinical practice for alternative approaches for both acute and preventive treatment. Occasionally, this need might arise in the context of low-frequency migraneurs who are not keen to use medication or fear the potential side effects. At the opposite end of the spectrum, clinicians might be faced with patients who have proven refractory to numerous medications. These patients may benefit from invasive treatment strategies. In recent years, promising strategies for migraine therapy have emerged alongside a progressively better understanding of the complex pathophysiology underlying this disease. This review discusses the most recent and evidence-based advances in non-pharmacological therapeutic approaches for migraine, offering alternatives to drug treatment for both the commonly encountered episodic cases as well as the more complex migraine phenotypes, which are capable of challenging even the headache specialist.

Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review

Background

Sphenopalatine ganglion is the largest collection of neurons in the calvarium outside of the brain. Over the past century, it has been a target for interventional treatment of head and facial pain due to its ease of access. Block, radiofrequency ablation, and neurostimulation have all been applied to treat a myriad of painful syndromes. Despite the routine use of these interventions, the literature supporting their use has not been systematically summarized. This systematic review aims to collect and summarize the level of evidence supporting the use of sphenopalatine ganglion block, radiofrequency ablation and neurostimulation.

Methods

Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Studies included in this review were compiled and analyzed for their treated medical conditions, study design, outcomes and procedural details. Studies were graded using Oxford Center for Evidence-Based Medicine for level of evidence. Based on the level of evidence, grades of recommendations are provided for each intervention and its associated medical conditions.

Results

Eighty-three publications were included in this review, of which 60 were studies on sphenopalatine ganglion block, 15 were on radiofrequency ablation, and 8 were on neurostimulation. Of all the studies, 23 have evidence level above case series. Of the 23 studies, 19 were on sphenopalatine ganglion block, 1 study on radiofrequency ablation, and 3 studies on neurostimulation. The rest of the available literature was case reports and case series. The strongest evidence lies in using sphenopalatine ganglion block, radiofrequency ablation and neurostimulation for cluster headache. Sphenopalatine ganglion block also has evidence in treating trigeminal neuralgia, migraines, reducing the needs of analgesics after endoscopic sinus surgery and reducing pain associated with nasal packing removal after nasal operations.

Conclusions

Overall, sphenopalatine ganglion is a promising target for treating cluster headache using blocks, radiofrequency ablation and neurostimulation. Sphenopalatine ganglion block also has some evidence supporting its use in a few other conditions. However, most of the controlled studies were small and without replications. Further controlled studies are warranted to replicate and expand on these previous findings.

Electronic supplementary material

The online version of this article (10.1186/s10194-017-0826-y) contains supplementary material, which is available to authorized users.

An update on migraine: current understanding and future directions

Migraine is a common brain disorder with high disability rates which involves a series of abnormal neuronal networks, interacting at different levels of the central and peripheral nervous system. An increase in the interest around migraine pathophysiology has allowed researchers to unravel certain neurophysiological mechanisms and neurotransmitter involvement culminating in the recent development of novel therapies, which might substantially change the clinical approach to migraine patients. The present review will highlight the current aspects of migraine pathophysiology, covering an understanding of the complex workings of the migraine state and the brain regions responsible for them. We will further discuss the therapeutic agents which have appeared in the most recent years for migraine care, from calcitonin gene-related peptide (CGRP) receptor antagonists, gepants; through serotonin 5-HT1F receptor agonists, ditans, and CGRP or CGRP receptor monoclonal antibodies to invasive and non-invasive neuromodulation techniques.

Cracking the neural code, treating paralysis and the future of bioelectronic medicine

The human nervous system is a vast network carrying not only sensory and movement information, but also information to and from our organs, intimately linking it to our overall health. Scientists and engineers have been working for decades to tap into this network and 'crack the neural code' by decoding neural signals and learning how to 'speak' the language of the nervous system. Progress has been made in developing neural decoding methods to decipher brain activity and bioelectronic technologies to treat rheumatoid arthritis, paralysis, epilepsy and for diagnosing brain-related diseases such as Parkinson's and Alzheimer's disease. In a recent first-in-human study involving paralysis, a paralysed male study participant regained movement in his hand, years after his injury, through the use of a bioelectronic neural bypass. This work combined neural decoding and neurostimulation methods to translate and re-route signals around damaged neural pathways within the central nervous system. By extending these methods to decipher neural messages in the peripheral nervous system, status information from our bodily functions and specific organs could be gained. This, one day, could allow real-time diagnostics to be performed to give us a deeper insight into a patient's condition, or potentially even predict disease or allow early diagnosis. The future of bioelectronic medicine is extremely bright and is wide open as new diagnostic and treatment options are developed for patients around the world.

External Trigeminal Nerve Stimulation for the Acute Treatment of Migraine: Open-Label Trial on Safety and Efficacy

OBJECTIVE

The aim of the current study is to assess the safety and efficacy of external trigeminal nerve stimulation (e-TNS) via a transcutaneous supraorbital stimulator as an acute treatment for migraine attacks.

MATERIALS AND METHODS

This was a prospective, open-labeled clinical trial conducted at the Columbia University Headache Center (NY, USA). Thirty patients who were experiencing an acute migraine attack with or without aura were treated with a one-hour session of e-TNS (CEFALY Technology) at the clinic. Pain intensity was scored using a visual analogue scale (VAS) before the treatment, after the one-hour treatment session, and at two hours after treatment initiation. Rescue migraine medication intake was recorded at 2 and 24 hours.

RESULTS

Thirty patients were included in the intention-to-treat analysis. Mean pain intensity was significantly reduced by 57.1% after the one-hour e-TNS treatment (-3.22 ± 2.40; p < 0.001) and by 52.8% at two hours (-2.98 ± 2.31; p < 0.001). No patients took rescue medication within the two-hour observation phase. Within the 24-hour follow-up, 34.6% of patients used a rescue medication. No adverse events or subjective complaints were reported.

CONCLUSIONS

The findings from this open-labeled study suggest that transcutaneous supraorbital neurostimulation may be a safe and effective acute treatment for migraine attacks, and merits further study with a double-blind, randomized, sham-controlled trial.

Sphenopalatine Ganglion (SPG): Stimulation Mechanism, Safety, and Efficacy

OBJECTIVE

To describe the history of and available data on sphenopalatine ganglion (SPG) neuromodulation in the treatment of headache up to the present.

BACKGROUND

The SPG has been a therapeutic target to treat primary headache disorders for over 100 years. Multiple destructive lesions have also been tried with variable rate and duration of success. Neurostimulation of the SPG for cluster headache was first described in 2007.

METHODS

This is not a systematic review. The authors review the anatomy and pathophysiology of the SPG and cluster headache and the important clinical trials, relating a history of how SPG neuromodulation reached the current state of approval in the European Union (EU) and pivotal registration study for cluster headache in the US.

RESULTS

The EU approved SPG stimulation for cluster headache with a CE Mark in February of 2012. Since then, several EU countries have elected to reimburse implantation for cluster headache, and over 300 patients have been implanted worldwide.

CONCLUSIONS

Success rates for implanted SPG neuromodulation in the experimental phase of the European randomized controlled trial, in the open label extension trial, and in the registry of patients implanted outside of the trial remain at about two-thirds of patients implanted being responders, defined as being able to terminate at least 50% of attacks or having at least a 50% decrease in attack frequency or both. A US pivotal registration study is underway to confirm these results and obtain FDA approval for this treatment for cluster headache patients. Further studies in migraine are also underway.

Current and novel insights into the neurophysiology of migraine and its implications for therapeutics

Migraine headache and its associated symptoms have plagued humans for two millennia. It is manifest throughout the world, and affects more than 1/6 of the global population. It is the most common brain disorder, and is characterized by moderate to severe unilateral headache that is accompanied by vomiting, nausea, photophobia, phonophobia, and other hypersensitive symptoms of the senses. While there is still a clear lack of understanding of its neurophysiology, it is beginning to be understood, and it seems to suggest migraine is a disorder of brain sensory processing, characterized by a generalized neuronal hyperexcitability. The complex symptomatology of migraine indicates that multiple neuronal systems are involved, including brainstem and diencephalic systems, which function abnormally, resulting in premonitory symptoms, ultimately evolving to affect the dural trigeminovascular system, and the pain phase of migraine. The migraineur also seems to be particularly sensitive to fluctuations in homeostasis, such as sleep, feeding and stress, reflecting the abnormality of functioning in these brainstem and diencephalic systems. Implications for therapeutic development have grown out of our understanding of migraine neurophysiology, leading to major drug classes, such as triptans, calcitonin gene-related peptide receptor antagonists, and 5-HT1F receptor agonists, as well as neuromodulatory approaches, with the promise of more to come. The present review will discuss the current understanding of the neurophysiology of migraine, particularly migraine headache, and novel insights into the complex neural networks responsible for associated neurological symptoms, and how interaction of these networks with migraine pain pathways has implications for the development of novel therapeutics.

An Update on Non-Pharmacological Neuromodulation for the Acute and Preventive Treatment of Migraine

OBJECTIVE

To review current neuromodulation treatments available for migraine therapy, both in the acute and preventive setting.

METHODS

The published literature was reviewed for studies reporting the effects of different neuromodulation strategies in migraine with and without aura. The use of non-invasive: single pulse transcranial magnetic stimulation, non-invasive vagal nerve stimulation, supraorbital nerve stimulation, and transcranial direct current stimulation, as well as invasive methods such as occipital nerve stimulation and sphenopalatine ganglion stimulation, are assessed.

RESULTS

The available evidence shows that non-invasive techniques represent promising treatment strategies, whereas an invasive approach should only be used where patients are refractory to other preventives, including non-invasive methods.

CONCLUSIONS

Neuromodulation is emerging as an exciting approach to migraine therapy, especially in the context of failure of commonly used medicines or for patients who do not tolerate common side effects. More studies with appropriate blinding strategies are needed to confirm the results of these new treatment opportunities.

Nonpainful remote electrical stimulation alleviates episodic migraine pain

Objective:

To evaluate the efficacy of remote nonpainful electrical upper arm skin stimulation in reducing migraine attack pain.

Methods:

This is a prospective, double-blinded, randomized, crossover, sham-controlled trial. Migraineurs applied skin electrodes to the upper arm soon after attack onset for 20 minutes, at various pulse widths, and refrained from medications for 2 hours. Patients were asked to use the device for up to 20 attacks.

Results:

In 71 patients (299 treatments) with evaluable data, 50% pain reduction was obtained for 64% of participants based on best of 200-μs, 150-μs, and 100-μs pulse width stimuli per individual vs 26% for sham stimuli. Greater pain reduction was found for active stimulation vs placebo; for those starting at severe or moderate pain, reduction (1) to mild or no pain occurred in 58% (25/43) of participants (66/134 treatments) for the 200-μs stimulation protocol and 24% (4/17; 8/29 treatments) for placebo (p = 0.02), and (2) to no pain occurred in 30% (13/43) of participants (37/134 treatments) and 6% (1/17; 5/29 treatments), respectively (p = 0.004). Earlier application of the treatment, within 20 minutes of attack onset, yielded better results: 46.7% pain reduction as opposed to 24.9% reduction when started later (p = 0.02).

Conclusion:

Nonpainful remote skin stimulation can significantly reduce migraine pain, especially when applied early in an attack. This is presumably by activating descending inhibition pathways via the conditioned pain modulation effect. This treatment may be proposed as an attractive nonpharmacologic, easy to use, adverse event free, and inexpensive tool to reduce migraine pain.

ClinicalTrials.gov identifier:

NCT02453399.

Classification of evidence:

This study provides Class III evidence that for patients with an acute migraine headache, remote nonpainful electrical stimulation on the upper arm skin reduces migraine pain.

Invasive and Non-invasive Electrical Pericranial Nerve Stimulation for the Treatment of Chronic Primary Headaches

Chronic primary headaches are widespread disorders which cause significant quality of life and socioprofessional impairment. Available pharmacological treatments have often a limited efficacy and/or can generate unbearable side effects. Electrical nerve stimulation is a well-known non-destructive method of pain modulation which has been recently applied to headache management. In this review, we summarise recent advances in invasive and non-invasive neurostimulation techniques targeting pericranial structures for the treatment of chronic primary headaches, chiefly migraine and cluster headache: occipital nerve, supraorbital nerve, vagus nerve, and sphenopalatine ganglion stimulations. Invasive neurostimulation therapies have offered a new hope to drug-refractory headache sufferers but are not riskless and should be proposed only to chronic patients who failed to respond to most existing preventives. Non-invasive neurostimulation devices are user-friendly, safe and well tolerated and are thus taking an increasing place in the multidisciplinary therapeutical armamentarium of primary headaches.

Current Approaches to Neuromodulation in Primary Headaches: Focus on Vagal Nerve and Sphenopalatine Ganglion Stimulation

Neuromodulation is a promising, novel approach for the treatment of primary headache disorders. Neuromodulation offers a new dimension in the treatment that is both easily reversible and tends to be very well tolerated. The autonomic nervous system is a logical target given the neurobiology of common primary headache disorders, such as migraine and the trigeminal autonomic cephalalgias (TACs). This article will review new encouraging results of studies from the most recent literature on neuromodulation as acute and preventive treatment in primary headache disorders, and cover some possible underlying mechanisms. We will especially focus on vagus nerve stimulation (VNS) and sphenopalatine ganglion (SPG) since they have targeted autonomic pathways that are cranial and can modulate relevant pathophysiological mechanisms. The initial data suggests these approaches will find an important role in headache disorder management going forward.

Sphenopalatine ganglion stimulation in cluster headache and other types of headache

Objectives The cluster headache is the most excruciatingly painful primary headache. In some patients, neither preventive treatment nor acute treatment is effective or treatment is poorly tolerated. The sphenopalatine ganglion (SPG) has an important role in the pathophysiology of cluster headache and, for this reason, SPG stimulation has been used to treat cluster headache. Methods We have reviewed the published literature on the role of the SPG in cluster headache and the use of different treatments targeting the SPG. Results Multiple procedures have been used over the SPG to treat pain and trigemino-autonomic symptoms in patients with refractory cluster headache. After obtaining good results in a small number of patients, a miniaturized stimulator was developed. Stimulation of the SPG with this device proved to be efficacious in acute and preventive treatment in a clinical trial involving patients with chronic refractory cluster headache. Implantation of the device is minimally invasive and the most frequent side-effects are mild, such as paraesthesia and pain over the maxillary area. In patients who have used the SPG device for longer than one year, the therapeutic effect remains effective and the side-effects decrease. Conclusions The reported studies have demonstrated that SPG stimulation is a safe and effective treatment for chronic cluster headache. Long-term studies have shown that the effect remains over time and this treatment could be a good choice in patients with chronic refractory headache. We need more data about its potential use in other forms of headache, such as other trigemino-autonomic headaches or migraine.

The surgical management of cephalalgia

PURPOSE OF REVIEW

Management of headache disorders is not part of most craniomaxillofacial surgery practices; however there are certain indications for surgical management of headaches by the craniomaxillofacial surgeon.

RECENT FINDINGS

Migraine headaches are the most amenable to surgical management and while the exact mechanism of migraine is unknown, a central or peripheral trigger such as compressive neuropathy of trigeminal nerve branches leading to neurogenic inflammation has been suggested. The primary management for episodic migraine headache should be lifestyle modification and medication, whereas for chronic migraine (>15 headache days/month) use of medication and botulinum neurotoxin is effective, whereas some patients may choose to explore surgical options. Trigger site decompression for chronic migraine surgically relieves anatomic impingement at various sites and has been shown to reduce by at least 50% the frequency, intensity, and duration of headaches in over 85% and elimination of headaches in almost 60%. Trigger points may also lead to exacerbation of cluster headaches and treatment with botulinum neurotoxin may reduce attacks.

SUMMARY

Trigger site decompression is an effective treatment for chronic migraine, as are botulinum neurotoxin injections in reducing attacks in cluster headaches. The craniomaxillofacial surgeon is uniquely qualified to treat these primary headache disorders.

New therapeutic approaches for the prevention and treatment of migraine

The management of patients with migraine is often unsatisfactory because available acute and preventive therapies are either ineffective or poorly tolerated. The acute treatment of migraine attacks has been limited to the use of analgesics, combinations of analgesics with caffeine, ergotamines, and the triptans. Successful new approaches for the treatment of acute migraine target calcitonin gene-related peptide (CGRP) and serotonin (5-hydroxytryptamine, 5-HT1F) receptors. Other approaches targeting the transient receptor potential vanilloid (TRPV1) receptor, glutamate, GABAA receptors, or a combination of 5-HT1B/1D receptors and neuronal nitric oxide synthesis have been investigated but have not been successful in clinical trials thus far. In migraine prevention, the most promising new approaches are humanised antibodies against CGRP or the CGRP receptor. Non-invasive and invasive neuromodulation approaches also show promise as both acute and preventive therapies, although further studies are needed to define appropriate candidates for these therapies and optimum protocols for their use.

Technical and surgical aspects of the sphenopalatine ganglion (SPG) microstimulator insertion procedure

Cluster headache (CH) is a debilitating, severe form of headache. A novel non-systemic therapy has been developed that produces therapeutic electrical stimulation to the sphenopalatine ganglion (SPG). A transoral surgical technique for inserting the Pulsante SPG Microstimulator into the pterygopalatine fossa (PPF) is presented herein. Technical aspects include detailed descriptions of the preoperative planning using computed tomography or cone beam computed tomography scans for presurgical digital microstimulator insertion into the patient-specific anatomy and intraoperative verification of microstimulator placement. Surgical aspects include techniques to insert the microstimulator into the proper midface location atraumatically. During the Pathway CH-1 and Pathway R-1 studies, 99 CH patients received an SPG microstimulator. Ninety-six had a microstimulator placed within the PPF during their initial procedure. Perioperative surgical sequelae included sensory disturbances, pain, and swelling. Follow-up procedures included placement of a second microstimulator on the opposite side (n=2), adjustment of the microstimulator lead location (n=13), re-placement after initial unsuccessful placement (n=1), and removal (n=5). This SPG microstimulator insertion procedure has sequelae comparable to other oral cavity procedures including tooth extractions, sinus surgery, and dental implant placement. Twenty-five of 29 subjects (86%) completing a self-assessment questionnaire indicated that the surgical effects were tolerable and 90% would make the same decision again.

Transcutaneous Supraorbital Nerve Stimulation (t-SNS) with the Cefaly® Device for Migraine Prevention: A Review of the Available Data

So far, among the different non-invasive neurostimulation methods, only transcutaneous supraorbital nerve stimulation (t-SNS) with the Cefaly® (Cefaly Technology sprl, Herstal, Belgium) device has randomized controlled trial-based evidence for safety and efficacy and obtained American Food and Drug Administration approval for the prevention of episodic migraine. In a double-blinded, randomized, sham-controlled trial on 67 episodic migraine patients (mean pre-treatment migraine days/month: 6.9), the 50% responder rate after 3 months was significantly higher in the active group (38.2%) than in the sham group (12.1%); attack frequency and total headache days were also significantly reduced, but not headache severity. Acute anti-migraine drug intake was reduced by 36.7% in the active group. Statistical sub-analysis suggested that t-SNS was more effective in patients with a higher attack frequency. In a large survey on 2313 Cefaly users about safety and satisfaction only 4.3% of subjects reported side effects, all of which were minor and fully reversible, the most frequent being intolerance to the paresthesia feeling and the most severe an allergic skin reaction to the electrode gel. The efficacy/safety ratio of the Cefaly device was therefore most favorable, especially when compared to preventive anti-migraine drugs. The therapeutic efficacy of t-SNS with Cefaly with low-frequency migraine (≤5 attacks/month) was recently confirmed in an open randomized trial. No published data are available in chronic migraine. According to preliminary results of a fluorodeoxyglucose-positron emission tomography study, Cefaly might exert its effect in migraine by increasing activity in crucial areas of the limbic system and salience matrix such as orbitofrontal and anterior cingulate cortices.

Prevalence of cranial autonomic parasympathetic symptoms in chronic migraine: Usefulness of a new scale

Background

Cranial autonomic symptoms (CAS) seem to appear in around half of migraine patients.

Objective

Our aim was to analyse the prevalence and profile of CAS, mainly of cranial autonomic parasympathetic symptoms (CAPS), in a series of patients with chronic migraine (CM) according the new criteria for autonomic symptoms in the current IHS classification.

Patients and methods

We recruited consecutive CM patients attending our headache clinic. Five CPAS were surveyed: lacrimation, conjunctival injection, eyelid oedema, ear fullness and nasal congestion. They were graded as 0 (absent), 1 (present and mild) and 2 (present and conspicuous); therefore the score in this CAPS scale ranges from 0 to 10 points. As a cranial autonomic sympathetic symptom (CSAS), we also asked about the presence of ptosis.

Results

We interviewed 100 CM patients. Their mean age was 45 years (18–63 years); 93 were females. Eighteen had no CAPS, while 82 reported at least one CAPS. There were only six patients with scores higher than 5, the mean and median CAPS being 2.1 and 2, respectively. Prevalence of CAPS was lacrimation (49%), conjunctival injection (44%), eyelid oedema (39%), ear fullness (30%) and nasal congestion (20%). Ptosis was reported by 42.

Conclusion

These results, by using for the first time an easy quantitative scale, confirm that (mild) CAPS are not the exception but the rule in CM patients. The score in this CAPS scale could be of help as a further endpoint in clinical trials or to be correlated with potential biomarkers of parasympathetic activation in primary headaches.

Occipital Nerve Stimulation for Migraine: A Systematic Review

Patients who suffer from migraines often report impaired quality of life. Occipital nerve stimulation (ONS) is a novel treatment modality for migraines, although few systematic reviews have evaluated whether this therapy is efficacious. The objective of this study was to evaluate the clinical efficacy and safety of ONS for treating migraine through a literature review. We performed a literature search to identify studies that investigated ONS for migraine treatment. Evidence levels of these studies were assessed by recommendations set by the University of Oxford Centre for Evidence-Based Medicine. Five randomized controlled trials, 4 retrospective studies, and one prospective study met the inclusion criteria. Results from the retrospective studies and case series indicated that ONS significantly reduced the pain intensity and the number of days with headache in patients with migraine. However, the evidence of ONS efficacy established by randomized controlled trials was limited. Improvement in the migraine disability assessment (MIDAS) score was more dramatic than improvement in the SF-36 score at follow-up. The mean complication incidence of ONS was 66% for the reviewed studies. Future clinical studies should optimize and standardize the ONS intervention process and identify the relationship among the surgical process, efficacy, and complications resulting from the procedure.

Neuromodulation in migraine: state of the art and perspectives

Migraine is a highly prevalent and disabling disease. The drugs prescribed for migraine prophylaxis can have intolerable side effects or can be ineffective. Neuromodulation techniques are increasingly used in neurology. Transcutaneous supraorbital nerve stimulation is effective in episodic migraine prevention, whereas vagus nerve stimulation provides interesting results in acute migraine therapy. Transcranial stimulation techniques gave variable, and sometimes contradictory, results. The visual cortex is the target of choice in migraine: studies in migraine prevention and aura acute treatment are encouraging. These noninvasive therapies appear safe with a low rate of side effects. Available studies of invasive occipital nerve stimulation in chronic migraine gave modest results; but invasive occipital nerve stimulation offers a new hope to highly disabled patients who failed to respond to any other treatment. In the future, neuromodulation will probably take an increasing place in migraine treatment, as add-on therapy or alternative to medications, especially because of its attractive safety profile.

A double-blind, placebo-controlled study of repetitive transnasal sphenopalatine ganglion blockade with tx360(®) as acute treatment for chronic migraine

Objective

To determine if repetitive sphenopalatine ganglion (SPG) blocks with 0.5% bupivacaine delivered through the Tx360® are superior in reducing pain associated with chronic migraine (CM) compared with saline.

Background

The SPG is a small concentrated structure of neuronal tissue that resides within the pterygopalatine fossa (PPF) in close proximity to the sphenopalatine foramen and is innervated by the maxillary division of the trigeminal nerve. From an anatomical and physiological perspective, SPG blockade may be an effective acute and preventative treatment for CM.

Method

This was a double-blind, parallel-arm, placebo-controlled, randomized pilot study using a novel intervention for acute treatment in CM. Up to 41 subjects could be enrolled at 2 headache specialty clinics in the US. Eligible subjects were between 18 and 80 years of age and had a history of CM defined by the second edition of the International Classification of Headache Disorders appendix definition. They were allowed a stable dose of migraine preventive medications that was maintained throughout the study. Following a 28-day baseline period, subjects were randomized by computer-generated lists of 2:1 to receive 0.5% bupivacaine or saline, respectively. The primary end-point was to compare numeric rating scale scores at pretreatment baseline vs 15 minutes, 30 minutes, and 24 hours postprocedure for all 12 treatments.

SPG blockade was accomplished with the Tx360®, which allows a small flexible soft plastic tube that is advanced below the middle turbinate just past the pterygopalatine fossa into the intranasal space. A 0.3 cc of anesthetic or saline was injected into the mucosa covering the SPG. The procedure is performed similarly in each nostril. The active phase of the study consisted of a series of 12 SPG blocks with 0.3 cc of 0.5% bupivacaine or saline provided 2 times per week for 6 weeks. Subjects were re-evaluated at 1 and 6 months postfinal procedure.

Results

The final dataset included 38 subjects, 26 in the bupivacaine group and 12 in the saline group. A repeated measures analysis of variance showed that subjects receiving treatment with bupivacaine experienced a significant reduction in the numeric rating scale scores compared with those receiving saline at baseline (M = 3.78 vs M = 3.18, P = .10), 15 minutes (M = 3.51 vs M = 2.53, P < .001), 30 minutes (M = 3.45 vs M = 2.41, P < .001), and 24 hours after treatment (M = 4.20 vs M = 2.85, P < .001), respectively. Headache Impact Test-6 scores were statistically significantly decreased in subjects receiving treatments with bupivacaine from before treatment to the final treatment (M_diff = −4.52, P = .005), whereas no significant change was seen in the saline group (M_diff = −1.50, P = .13).

Conclusion

SPG blockade with bupivacaine delivered repetitively for 6 weeks with the Tx360® device demonstrates promise as an acute treatment of headache in some subjects with CM. Statistically significant headache relief is noted at 15 and 30 minutes and sustained at 24 hours for SPG blockade with bupivacaine vs saline. The Tx360® device was simple to use and not associated with any significant or lasting adverse events. Further research on sphenopalatine ganglion blockade is warranted.