Neuromodulation of chronic headaches: position statement from the European Headache Federation

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.

Efficacy of Occipital Nerve Stimulation in Trigeminal Autonomic Cephalalgias: A Systematic Review

BACKGROUND

Trigeminal autonomic cephalalgias (TACs) are a group of highly disabling primary headache disorders. Although pharmacological treatments exist, they are not always effective or well tolerated. Occipital nerve stimulation (ONS) is a potentially effective surgical treatment.

OBJECTIVE

To perform a systematic review of the efficacy of ONS in treating TACs.

METHODS

A systematic review was performed using Medline, Embase, and Cochrane databases. Primary outcomes were reduction in headache intensity, duration, and frequency. Secondary outcomes included adverse event rate and reduction in medication use. Because of large differences in outcome measures, data for patients suffering from short-lasting, unilateral, and neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and cranial autonomic symptoms (SUNA) were reported separately. Risk of bias was assessed using the NIH Quality Assessment Tools.

RESULTS

A total of 417 patients from 14 published papers were included in the analysis, of which 15 patients were in the SUNCT/SUNA cohort. The mean reduction in headache intensity and duration was 26.2% and 31.4%, respectively. There was a mean reduction in headache frequency of 50%, as well as a 61.2% reduction in the use of abortive medications and a 31.1% reduction in the use of prophylactic medications. In the SUNCT/SUNA cohort, the mean decrease in headache intensity and duration was 56.8% and 42.8%. The overall responder rate, defined as a >50% reduction in attack frequency, was 60.8% for the non-SUNCT/non-SUNA cohort and 66.7% for the SUNCT/SUNA cohort. Adverse events requiring repeat surgery were reported in 33% of cases. Risk of bias assessment suggests that articles included in this review had reasonable internal validity.

CONCLUSION

ONS may be an effective surgical treatment for approximately two thirds of patients with medically refractory TACs.

European Academy of Neurology guidelines on the treatment of cluster headache

BACKGROUND AND PURPOSE

Cluster headache is a relatively rare, disabling primary headache disorder with a major impact on patients' quality of life. This work presents evidence-based recommendations for the treatment of cluster headache derived from a systematic review of the literature and consensus among a panel of experts.

METHODS

The databases PubMed (Medline), Science Citation Index, and Cochrane Library were screened for studies on the efficacy of interventions (last access July 2022). The findings in these studies were evaluated according to the recommendations of the European Academy of Neurology, and the level of evidence was established using GRADE (Grading of Recommendations Assessment, Development, and Evaluation).

RECOMMENDATIONS

For the acute treatment of cluster headache attacks, there is a strong recommendation for oxygen (100%) with a flow of at least 12 L/min over 15 min and 6 mg subcutaneous sumatriptan. Prophylaxis of cluster headache attacks with verapamil at a daily dose of at least 240 mg (maximum dose depends on efficacy and tolerability) is recommended. Corticosteroids are efficacious in cluster headache. To reach an effect, the use of at least 100 mg prednisone (or equivalent corticosteroid) given orally or at up to 500 mg iv per day over 5 days is recommended. Lithium, topiramate, and galcanezumab (only for episodic cluster headache) are recommended as alternative treatments. Noninvasive vagus nerve stimulation is efficacious in episodic but not chronic cluster headache. Greater occipital nerve block is recommended, but electrical stimulation of the greater occipital nerve is not recommended due to the side effect profile.

Debate: differences and similarities between tension-type headache and migraine

Tension-type headache (TTH) and migraine are two common primary headaches distinguished by clinical characteristics according to the 3^rd edition of the International Classification of Headache Disorders. Migraine is identified by specific features such as being more prevalent in females, being aggravated by physical activity, certain genetic factors, having photophobia, phonophobia, nausea, vomiting, or aura, and responding to specific drugs. Nonetheless, TTH and migraine share some common characteristics, such as onset occurring in the 20 s, and being triggered by psychological factors like stress, moderate pain severity, and mild nausea in chronic TTH. Both conditions involve the trigeminovascular system in their pathophysiology. However, distinguishing between TTH and migraine in clinical practice, research, and epidemiological studies can be challenging, as there is a lack of specific diagnostic tests and biomarkers. Moreover, both conditions may coexist, further complicating the diagnostic process. This review aims to explore the similarities and differences in the pathophysiology, epidemiology, burden and disability, comorbidities, and responses to pharmacological and non-pharmacological treatments of TTH and migraine. The review also discusses future research directions to address the diagnostic challenges and improve the understanding and management of these conditions.

Neurotechnology for Pain

Neurotechnologies for treating pain rely on electrical stimulation of the central or peripheral nervous system to disrupt or block pain signaling and have been commercialized to treat a variety of pain conditions. While their adoption is accelerating, neurotechnologies are still frequently viewed as a last resort, after many other treatment options have been explored. We review the pain conditions commonly treated with electrical stimulation, as well as the specific neurotechnologies used for treating those conditions. We identify barriers to adoption, including a limited understanding of mechanisms of action, inconsistent efficacy across patients, and challenges related to selectivity of stimulation and off-target side effects. We describe design improvements that have recently been implemented, as well as some cutting-edge technologies that may address the limitations of existing neurotechnologies. Addressing these challenges will accelerate adoption and change neurotechnologies from last-line to first-line treatments for people living with chronic pain.

Primary headache disorders: From pathophysiology to neurostimulation therapies

Primary headache disorders including migraine, cluster headache, and tension-type headache are among the most common disabling diseases worldwide. The unclear pathogenesis of primary headache disorders has led to high rates of misdiagnosis and limited available treatment options. In this review, we have summarized the pathophysiological factors for a better understanding of primary headache disorders. Advances in functional neuroimaging, genetics, neurophysiology have indicated that cortical hyperexcitability, regional brain dysfunction, central sensitization and neuroplasticity changes play vital roles in the development of primary headache disorders. Moreover, we have also discussed a series of neurostimulation approaches with their stimulation mechanism, safety and efficacy for prevention and treatment of primary headache disorders. Noninvasive or implantable neurostimulation techniques show great promise for treating refractory primary headache disorders.

An open-label observational study and meta-analysis of non-invasive vagus nerve stimulation in medically refractory chronic cluster headache

Background

Many patients with cluster headache (CH) are inadequately controlled by current treatment options. Non-invasive vagus nerve stimulation (nVNS) is reported to be effective in the management of CH though some studies suggest that it is ineffective.

Objective

To assess the safety and efficacy of nVNS in chronic cluster headache (CCH) patients.

Method

We prospectively analysed data from 40 patients with refractory CCH in this open-label, observational study. Patients were seen in tertiary headache clinics at the National Hospital for Neurology and Neurosurgery and trained to use nVNS as preventative therapy. Patients were reivewed at one month and then three-monthly from onset. The primary endpoint was number of patients achieving ≥50% reduction in attack frequency at 3  months. A meta-analysis of all published studies evaluating the efficacy of nVNS in CCH was also conducted. We searched MEDLINE and EMBASE for all studies investigating the use of nVNS as a preventive or adjunctive treatment for CCH with five or more participants. Combined mean difference and responder proportions with 95% confidence intervals (CI) were calculated from the included studies.

Results

17/40 patients (43%) achieved ≥50% reduction in attack frequency at 3  months. There was a significant reduction in monthly attack frequency from a baseline of 124 (±67) attacks to 79 (±63) attacks in month 3 (mean difference 44.7; 95% CI 25.1 to 64.3; p < 0.001). In month 3, there was also a 1.2-point reduction in average severity from a baseline Verbal Rating Scale of 8/10 (95% CI 0.5 to 1.9; p = 0.001). Four studies, along with the present study, were deemed eligible for meta-analysis, which showed a responder proportion of 0.35 (95% CI 0.07 to 0.69, n = 137) and a mean reduction in headache frequency of 35.3 attacks per month (95% CI 11.0 to 59.6, n = 108), from a baseline of 105 (±22.7) attacks per month.

Conclusion

This study highlights the potential benefit of nVNS in CCH, with significant reductions in headache frequency and severity. To better characterise the effect, randomised sham-controlled trials are needed to confirm the beneficial response of VNS reported in some, but not all, open-label studies.

Minimally Invasive Nerve- and Muscle-Sparing Surgical Decompression for Occipital Neuralgia

BACKGROUND

Occipital neuralgia is a well-defined type of headache, and its treatment algorithm is still debated across medical specialties. From the analysis of the literature, it appears that surgical decompression of the occipital nerves is the most effective invasive approach to improve the quality of life of patients with occipital neuralgia refractory to medications. The authors describe here a minimally invasive nerve- and muscle-sparing technique to decompress the occipital nerves.

METHODS

The results in terms of reduction of migraine days per month, use of medications, pain evaluation, and decrease in Migraine Headache Index were analyzed by means of a retrospective chart review of 87 patients who underwent nerve- and muscle-sparing surgical decompression of the greater and lesser monolateral or bilateral occipital nerves in their institution and were followed up for at least 12 months. The surgical technique is described in detail.

RESULTS

Surgical decompression significantly reduced occipital neuralgia burden (at least 50% improvement) in 91% of patients, with 45% reporting a complete remission of occipital pain. Days with pain per month decreased by 80%, chronic background pain intensity decreased by 81%, and pain intensity during crisis decreased by 76%. Accordingly, drug use dropped by approximately 70%. Only minor complications were reported in four patients.

CONCLUSIONS

The described technique could contribute to and further support surgical decompression as the first option among the invasive approaches to treat occipital neuralgia. Results corroborate previous findings, adding a less-invasive, nerve- and muscle-sparing approach.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Migraine and Neuromodulation: A Literature Review

Migraine is not only known to be one of the most common causes of a headache around the globe but is also the leading neurologic cause of disability worldwide. Migraine has significant social and economic effects. It not only hampers patients' quality of life but also hampers work, public conduct, and family life. Migraine is one of the leading causes of morbidity in the world, so effective management is critical. Currently, medical management is the mainstay remedial approach for migraine, but with time, non-pharmacological approaches, especially neuromodulation, are gaining popularity with a shred of solid backing evidence. Neuromodulation is the process in which specific devices are used to excite the central nervous system or peripheral nervous system with electric or magnetic, or any other form of energy to regulate the abnormal behavior of neural pathways that have occurred due to the disease process. Neuromodulation devices as approved by Food and Drug Administration include non-invasive Vagus nerve stimulators, single-pulse transcranial magnetic stimulators, and transcutaneous supraorbital neurostimulators. The purpose of this study is to summarize the information about the advances relating to neuromodulation concerning managing and preventing migraine. This Narrative review article is prepared after analyzing various research papers and publications on PubMed and Google Scholar. This article holds brief information on understanding neuromodulation, its mechanism, its implication in managing migraine, and its different modalities with their mechanism of action and contraindications. These neuromodulation techniques can certainly be used to deal with acute migraine attacks and inhibit their progression to chronic illness. Research is required on the application of neuromodulation in the early diagnosis of migraine, which is what we still lack as a whole medical fraternity.

Digitalized transcranial electrical stimulation: A consensus statement

OBJECTIVE

Although relatively costly and non-scalable, non-invasive neuromodulation interventions are treatment alternatives for neuropsychiatric disorders. The recent developments of highly-deployable transcranial electric stimulation (tES) systems, combined with mobile-Health technologies, could be incorporated in digital trials to overcome methodological barriers and increase equity of access. The study aims are to discuss the implementation of tES digital trials by performing a systematic scoping review and strategic process mapping, evaluate methodological aspects of tES digital trial designs, and provide Delphi-based recommendations for implementing digital trials using tES.

METHODS

We convened 61 highly-productive specialists and contacted 8 tES companies to assess 71 issues related to tES digitalization readiness, and processes, barriers, advantages, and opportunities for implementing tES digital trials. Delphi-based recommendations (>60% agreement) were provided.

RESULTS

The main strengths/opportunities of tES were: (i) non-pharmacological nature (92% of agreement), safety of these techniques (80%), affordability (88%), and potential scalability (78%). As for weaknesses/threats, we listed insufficient supervision (76%) and unclear regulatory status (69%). Many issues related to methodological biases did not reach consensus. Device appraisal showed moderate digitalization readiness, with high safety and potential for trial implementation, but low connectivity.

CONCLUSIONS

Panelists recognized the potential of tES for scalability, generalizability, and leverage of digital trials processes; with no consensus about aspects regarding methodological biases.

SIGNIFICANCE

We further propose and discuss a conceptual framework for exploiting shared aspects between mobile-Health tES technologies with digital trials methodology to drive future efforts for digitizing tES trials.

Applying a biopsychosocial model to migraine: rationale and clinical implications

Migraine is a complex condition in which genetic predisposition interacts with other biological and environmental factors determining its course. A hyperresponsive brain cortex, peripheral and central alterations in pain processing, and comorbidities play a role from an individual biological standpoint. Besides, dysfunctional psychological mechanisms, social and lifestyle factors may intervene and impact on the clinical phenotype of the disease, promote its transformation from episodic into chronic migraine and may increase migraine-related disability.Thus, given the multifactorial origin of the condition, the application of a biopsychosocial approach in the management of migraine could favor therapeutic success. While in chronic pain conditions the biopsychosocial approach is already a mainstay of treatment, in migraine the biomedical approach is still dominant. It is instead advisable to carefully consider the individual with migraine as a whole, in order to plan a tailored treatment. In this review, we first reported an analytical and critical discussion of the biological, psychological, and social factors involved in migraine. Then, we addressed the management implications of the application of a biopsychosocial model discussing how the integration between non-pharmacological management and conventional biomedical treatment may provide advantages to migraine care.

Vagus nerve stimulation for conservative therapy-refractive epilepsy and depression

Numerous studies confirm that the vagus nerve stimulation (VNS) is an efficient, indirect neuromodulatory therapy with electrically induced current for epilepsy that cannot be treated by epilepsy surgery and is therapy-refractory and for drug therapy-refractory depression. VNS is an established, evidence-based and in the long-term cost-effective therapy in an interdisciplinary overall concept.Long-term data on the safety and tolerance of the method are available despite the heterogeneity of the patient populations. Stimulation-related side effects like hoarseness, paresthesia, cough or dyspnea depend on the stimulation strength and often decrease with continuing therapy duration in the following years. Stimulation-related side effects of VNS can be well influenced by modifying the stimulation parameters. Overall, the invasive vagus nerve stimulation may be considered as a safe and well-tolerated therapy option.For invasive and transcutaneous vagus nerve stimulation, antiepileptic and antidepressant as well as positive cognitive effects could be proven. In contrast to drugs, VNS has no negative effect on cognition. In many cases, an improvement of the quality of life is possible.iVNS therapy has a low probability of complete seizure-freedom in cases of focal and genetically generalized epilepsy. It must be considered as palliative therapy, which means that it does not lead to healing and requires the continuation of specific medication. The functional principle is a general reduction of the neuronal excitability. This effect is achieved by a slow increase of the effectiveness sometimes over several years. Responders are those patients who experience a 50% reduction of the seizure incidence. Some studies even reveal seizure-freedom in 20% of the cases. Currently, it is not possible to differentiate between potential responders and non-responders before therapy/implantation.The current technical developments of the iVNS generators of the new generation like closed-loop system (cardiac-based seizure detection, CBSD) reduce also the risk for SUDEP (sudden unexpected death in epilepsy patients), a very rare, lethal complication of epilepsies, beside the seizure severity.iVNS may deteriorate an existing sleep apnea syndrome and therefore requires possible therapy interruption during nighttime (day-night programming or magnet use) beside the close cooperation with sleep physicians.The evaluation of the numerous iVNS trials of the past two decades showed multiple positive effects on other immunological, cardiological, and gastroenterological diseases so that additional therapy indications may be expected depending on future study results. Currently, the vagus nerve stimulation is in the focus of research in the disciplines of psychology, immunology, cardiology as well as pain and plasticity research with the desired potential of future medical application.Beside invasive vagus nerve stimulation with implantation of an IPG and an electrode, also devices for transdermal and thus non-invasive vagus nerve stimulation have been developed during the last years. According to the data that are currently available, they are less effective with regard to the reduction of the seizure severity and duration in cases of therapy-refractory epilepsy and slightly less effective regarding the improvement of depression symptoms. In this context, studies are missing that confirm high evidence of effectiveness. The same is true for the other indications that have been mentioned like tinnitus, cephalgia, gastrointestinal complaints etc. Another disadvantage of transcutaneous vagus nerve stimulation is that the stimulators have to be applied actively by the patients and are not permanently active, in contrast to implanted iVNS therapy systems. So they are only intermittently active; furthermore, the therapy adherence is uncertain.

Diagnostic protocols and newer treatment modalities for cluster headache

Cluster Headaches are one of the most arguably severe forms of primary headache syndrome that affects humans. Although it is relatively uncommon, it has a significant impact on the quality of life. It is a multifactorial disease that has risk factors ranging from seasonal changes, lifestyle habits to genetics. It occurs in 2 forms- Episodic and Chronic, each having its well-defined Diagnostic Criteria. Moreover, Cluster Headache has an exhaustive list of options for both Preventive and Abortive treatment. This article focuses on Cluster Headache, its pathophysiology, risk factors, differentials, and its diverse treatment modalities. In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till October 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: "Cluster Headache," "Triptans," "Neuromodulation," and "Migraine." We explored the literature on Cluster Headache for its epidemiology, pathophysiology, the role of various genes and how they bring about the disease as well as its episodic and chronic variants, and treatment options. Although we have a wide variety of options for Preventive and Abortive therapy, newer more effective pharmacological and non-pharmacological interventions are being developed, and must be integrated into new treatment protocols.

Cluster Headache is Still Lurking in the Shadows

Cluster headache, apart from its legendary reputation as the most violent headache that can exist, suffers from an average 60-month delay in diagnosis. The simplicity of the clinical manifestations, although dramatic, makes this delay inexplicable. The education of emergency department physicians and various specialists not specifically dedicated to headaches allows cluster headache to remain in a lurking position with flourishing periods of disease that are often unpredictable in both onset and disappearance. Older drugs have always shown high efficacy but also an equally high rate of adverse events, often discouraging their appropriate use. The availability of a new drug class such as monoclonal antibodies for calcitonin gene-related peptide or its receptor (CGRP_(r)), which have already been efficient for migraine, shows a jeopardized geography of access in the world, and this favors the progression of the episodic form into chronic and of the chronic into refractory.

Remote Electrical Neuromodulation (REN) for the Acute Treatment of Menstrual Migraine: a Retrospective Survey Study of Effectiveness and Tolerability

INTRODUCTION

Migraine is one of the most prevalent neurological disorders worldwide, and estimations are that 60% of women who suffer from migraines experience attacks that are associated with menstruation. Menstrual migraines are typically more debilitating and less responsive to pharmacological treatment. Remote electrical neuromodulation (REN) is a non-pharmacological abortive treatment of migraine headache. The current study evaluated the self-reported effectiveness and tolerability of REN for the acute treatment of menstrual migraine, via a retrospective structured survey that was sent to adult female REN users.

METHODS

Women aged 18-55 years who experience menstrually related or pure menstrual migraine and have completed at least four REN treatments, participated in this retrospective, observational survey study. Participants completed a short online survey assessing effectiveness, satisfaction, and safety outcomes.

RESULTS

Ninety-one participants qualified for the analysis, out of which 74.7% (68/91) reported that the treatment was at least moderately effective (moderately effective 37.4%, very effective 26.4%, extremely effective 11.0%). Additionally, 45.1% (41/91) reported satisfaction from REN (slightly satisfied 33%, extremely satisfied 12.1%), while 34.1% were neutral and 20.9% (19/91) were not satisfied. Lastly, 100% of the participants reported that the treatment is at least moderately tolerable (moderately tolerable 8.8%, very tolerable 20.9%, extremely tolerable 70.3%), and 13.2% (12/91) of respondents reported mild short-term side effects.

CONCLUSIONS

Nearly 75% reported that the treatment was at least moderately effective, 45% reported satisfaction, and 100% of the participants reported that the treatment is at least moderately tolerable. Thirteen percent reported mild short-term side effects. REN was thus reported as effective for menstrual migraine by most participants and was very well tolerated. Therefore, REN may provide a safe, non-pharmacological alternative for the acute treatment of menstrual migraine. CLINICALTRIAL.

GOV REGISTRATION NUMBER

NCT04600388.

Analgesic efficacy of a portable, disposable, and self-applied transcutaneous electrical nerve stimulation device during migraine attacks: A real-life randomized controlled trial

OBJECTIVE

The objective of this study was to evaluate the analgesic efficacy of a portable, disposable, and home self-applied transcutaneous electrical nerve stimulation (TENS) device during migraine attacks.

BACKGROUND

TENS has been used as a noninvasive treatment for migraine, but there are no reports on the outcomes following use of this treatment option for use at home during migraine attacks.

DESIGN AND METHODS

A double-blind, randomized controlled trial was conducted over 3 months, with monthly assessments. Active placebos (sham group) were in place and were allocated at a 1:1 ratio. Adult patients who had been diagnosed with migraine by a specialist were included. Pain intensity levels and functional disability were measured before and after the 20-min self-applied TENS intervention during the migraine attacks.

RESULTS

Seventy-four participants were randomly allocated to the sham and intervention groups. Although both groups of subjects reported lower pain scores, the intervention group showed a statistically significant reduction in pain scores compared to the sham group.

CONCLUSION

In our controlled trial, the use of a self-applied, TENS device is safe and effective in relieving pain associated with migraine attacks. Participants in the intervention group showed a statistically significant improvement in pain and functional disability scores. TENS has been used as a noninvasive treatment for migraine, but there are no reports on the outcomes following use of this treatment option for use at home during migraine attacks. This double-blind, randomized controlled trial had 2 groups: active-placebo and intervention. Seventy-four participants were randomly allocated. Participants in the intervention group showed a statistically significant improvement in pain and functional disability scores.

Investigation of cortical thickness and volume during spontaneous attacks of migraine without aura: a 3-Tesla MRI study

BACKGROUND

Structural imaging has revealed changes in cortical thickness in migraine patients compared to healthy controls is reported, but presence of dynamic cortical and subcortical changes during migraine attack versus inter-ictal phase is unknown. The aim of the present study was to investigate possible changes in cortical thickness during spontaneous migraine attacks. We hypothesized that pain-related cortical area would be affected during the attack compared to an inter-ictal phase.

METHODS

Twenty-five patients with migraine without aura underwent three-dimensional T1-weighted imaging on a 3-Tesla MRI scanner during spontaneous and untreated migraine attacks. Subsequently, 20 patients were scanned in the inter-ictal phase, while 5 patients did not show up for the inter-ictal scan. Four patients were excluded from the analysis because of bilateral migraine pain and another one patient was excluded due to technical error in the imaging. Longitudinal image processing was done using FreeSurfer. Repeated measures ANOVA was used for statistical analysis and to control for multiple comparison the level of significance was set at p = 0.025.

RESULTS

In a total of 15 patients, we found reduced cortical thickness of the precentral (p = 0.023), pericalcarine (p = 0.024), and temporal pole (p = 0.017) cortices during the attack compared to the inter-ictal phase. Cortical volume was reduced in prefrontal (p = 0.018) and pericalcarine (p = 0.017) cortices. Hippocampus volume was increased during attack (p = 0.007). We found no correlations between the pain side or any other clinical parameters and the reduced cortical size.

CONCLUSION

Spontaneous migraine attacks are accompanied by transient reduced cortical thickness and volume in pain-related areas. The findings constitute a fingerprint of acute pain in migraine patients, which can be used as a possible biomarker to predict antimigraine treatment effect in future studies.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov ( NCT02202486 ).

Focused Ultrasound (FUS) for Chronic Pain Management: Approved and Potential Applications

Chronic pain is one of the leading causes of disability and disease burden worldwide, accounting for a prevalence between 6.9% and 10% in the general population. Pharmacotherapy alone results ineffective in about 70-60% of patients in terms of a satisfactory degree of pain relief. Focused ultrasound is a promising tool for chronic pain management, being approved for thalamotomy in chronic neuropathic pain and for bone metastases-related pain treatment. FUS is a noninvasive technique for neuromodulation and for tissue ablation that can be applied to several tissues. Transcranial FUS (tFUS) can lead to opposite biological effects, depending on stimulation parameters: from reversible neural activity facilitation or suppression (low-intensity, low-frequency ultrasound, LILFUS) to irreversible tissue ablation (high-intensity focused ultrasounds, HIFU). HIFU is approved for thalamotomy in neuropathic pain at the central nervous system level and for the treatment of facet joint osteoarthritis at the peripheral level. Potential applications include HIFU at the spinal cord level for selected cases of refractory chronic neuropathic pain, knee osteoarthritis, sacroiliac joint disease, intervertebral disc nucleolysis, phantom limb, and ablation of peripheral nerves. FUS at nonablative dosage, LILFUS, has potential reversible and tissue-selective effects. FUS applications at nonablative doses currently are at a research stage. The main potential applications include targeted drug and gene delivery through the Blood-Brain Barrier, assessment of pain thresholds and study of pain, and reversible peripheral nerve conduction block. The aim of the present review is to describe the approved and potential applications of the focused ultrasound technology in the field of chronic pain management.

The Promising Effect of Nerve Decompression in Trigeminal Autonomic Cephalalgias: Report of Case Series

Trigeminal Autonomic Cephalalgias (TAC) are excruciating headaches with limited treatment options. The chronic forms of TACs, including chronic cluster, chronic paroxysmal hemicrania, and hemicrania continua, are disabling conditions. In addition to drug therapy, there are some studies regarding nerve blocking and nerve stimulation with acceptable results. Here we report four cases of decompression nerve surgery with promising results on pain control in these difficult to treat headaches.

Implantable Peripheral Nerve Stimulation for Trigeminal Neuropathic Pain: A Systematic Review and Meta-Analysis

OBJECTIVES

Implantable peripheral nerve stimulation has been increasingly used to treat neuropathic pain. This neuromodulation strategy may be an alternative option for intractable trigeminal neuropathic pain; however, evidence for this treatment approach remains limited. A systematic review was conducted to identify studies of patients that underwent peripheral nerve stimulation implantation for trigeminal neuropathic pain.

MATERIALS AND METHODS

Databases including, PubMed, EMBASE, and Cochrane Library were searched up to October 5, 2020. The primary outcomes were changes in pain scores and response rates of neuromodulation therapy. A random effects model was used for meta-analysis. Subgroup analysis was performed to examine the source of heterogeneity.

RESULTS

Thirteen studies including 221 participants were evaluated. The estimated response rate of neuromodulation treatment was 61.3% (95% CI: 44.4-75.9%, I²  = 70.733%, p < 0.0001) at the last follow-up. The overall reduction in pain scores was 2.363 (95% CI: 1.408-3.319, I²  = 85.723%, p < 0.0001). Subgroup analysis further confirmed that stimulation target (peripheral branch vs. trigeminal ganglion vs. trigeminal nerve root) contributed the heterogeneity across enrolled studies. Better clinical outcome was associated with stimulation of the trigeminal peripheral branch (p < 0.0001).

CONCLUSION

Peripheral nerve stimulation may be a promising approach in the management of trigeminal neuropathic pain, especially for patients intractable to conventional therapy.

Occipital Nerve Stimulation for Refractory Chronic Cluster Headache: A Cost-Effectiveness Study

INTRODUCTION

Occipital nerve stimulation (ONS) is proposed to treat refractory chronic cluster headache (rCCH), but its cost-effectiveness has not been evaluated, limiting its diffusion and reimbursement.

MATERIALS AND METHODS

We performed a before-and-after economic study, from data collected prospectively in a nation-wide registry. We compared the cost-effectiveness of ONS associated with conventional treatment (intervention and postintervention period) to conventional treatment alone (preintervention period) in the same patients. The analysis was conducted on 76 rCCH patients from the French healthcare perspective at three months, then one year by extrapolation. Because of the impact of the disease on patient activity, indirect cost, such as sick leave and disability leave, was assessed second.

RESULTS

The average total cost for three months was €7602 higher for the ONS strategy compared to conventional strategy with a gain of 0.07 quality-adjusted life-years (QALY), the incremental cost-effectiveness ratio (ICER) was then €109,676/QALY gained. The average extrapolated total cost for one year was €1344 lower for the ONS strategy (p = 0.5444) with a gain of 0.28 QALY (p < 0.0001), the ICER was then €-4846/QALY gained. The scatter plot of the probabilistic bootstrapping had 80% of the replications in the bottom right-hand quadrant, indicating that the ONS strategy is dominant. The average indirect cost for three months was €377 lower for the ONS strategy (p = 0.1261).

DISCUSSION

This ONS cost-effectiveness study highlighted the limitations of a short-time horizon in an economic study that may lead the healthcare authorities to reject an innovative strategy, which is actually cost-effective. One-year extrapolation was the proposed solution to obtain results on which healthcare authorities can base their decisions.

CONCLUSION

Considering the burden of rCCH and the efficacy and safety of ONS, the demonstration that ONS is dominant should help its diffusion, validation, and reimbursement by health authorities in this severely disabled population.

Long-Term Efficacy of Occipital Nerve Stimulation for Medically Intractable Cluster Headache

BACKGROUND

Occipital nerve stimulation (ONS) has been proposed to treat refractory chronic cluster headache (rCCH) but its efficacy has only been showed in small short-term series.

OBJECTIVE

To evaluate ONS long-term efficacy in rCCH.

METHODS

We studied 105 patients with rCCH, treated by ONS within a multicenter ONS prospective registry. Efficacy was evaluated by frequency, intensity of pain attacks, quality of life (QoL) EuroQol 5 dimensions (EQ5D), functional (Headache Impact Test-6, Migraine Disability Assessment) and emotional (Hospital Anxiety Depression Scale [HAD]) impacts, and medication consumption.

RESULTS

At last follow-up (mean 43.8 mo), attack frequency was reduced >50% in 69% of the patients. Mean weekly attack frequency decreased from 22.5 at baseline to 9.9 (P < .001) after ONS. Preventive and abortive medications were significantly decreased. Functional impact, anxiety, and QoL significantly improved after ONS. In excellent responders (59% of the patients), attack frequency decreased by 80% and QoL (EQ5D visual analog scale) dramatically improved from 37.8/100 to 73.2/100. When comparing baseline and 1-yr and last follow-up outcomes, efficacy was sustained over time. In multivariable analysis, low preoperative HAD-depression score was correlated to a higher risk of ONS failure. During the follow-up, 67 patients experienced at least one complication, 29 requiring an additional surgery: infection (6%), lead migration (12%) or fracture (4.5%), hardware dysfunction (8.2%), and local pain (20%).

CONCLUSION

Our results showed that long-term efficacy of ONS in CCH was maintained over time. In responders, ONS induced a major reduction of functional and emotional headache-related impacts and a dramatic improvement of QoL. These results obtained in real-life conditions support its use and dissemination in rCCH patients.

Occipital Nerve Stimulation for Pain Modulation in Drug-Resistant Chronic Cluster Headache

Occipital nerve stimulation (ONS) is a surgical treatment proposed for drug-resistant chronic cluster headache (drCCH). Long-term series assessing its efficacy are scarce. We designed a retrospective observational study with consecutive sampling, evaluating the follow-up of 17 drCCH patients who underwent ONS. Our main endpoint was the reduction the rate of attacks per week. We also evaluated the pain intensity through the Visual Analogue Scale (VAS), patient overall perceived improvement and decrease in oral medication intake. After a median follow-up of 6.0 years (4.5–9.0), patients decreased from a median of 30 weekly attacks to 22.5 (5.6–37.5, p = 0.012), 7.5 at 1 year (p = 0.006) and 15.0 at the end of follow-up (p = 0.041). The VAS decreased from a median of 10.0 to 8.0 (p = 0.011) at three months, to 7.0 (p = 0.008) at twelve months and 7.0 (p = 0.003) at the end of the follow-up. A total of 23.5% had an overall perceived improvement of ≥70% at 3 months, 41.2% at 1 year and 27.8% at the end of follow-up. Reducing prophylactic oral medication was possible in 76.5% and it was stopped in 17.7%. Triptan use decreased in all the responder patients and 17.7% stopped its intake. A total of 41.2% presented mild adverse events. In conclusion, our long-term experience suggests that ONS could be an interesting option for drCCH-selected patients, as it is a beneficial and minimally invasive procedure with no serious adverse events.

Non-Pharmacological Approaches to Headaches: Non-Invasive Neuromodulation, Nutraceuticals, and Behavioral Approaches

Significant side effects or drug interactions can make pharmacological management of headache disorders very difficult. Non-conventional and non-pharmacological treatments are becoming increasingly used to overcome these issues. In particular, non-invasive neuromodulation, nutraceuticals, and behavioral approaches are well tolerated and indicated for specific patient categories such as adolescents and pregnant women. This paper aims to present the main approaches reported in the literature in the management of headache disorders. We therefore reviewed the available literature published between 2010 and 2020 and performed a narrative presentation for each of the three categories (non-invasive neuromodulation, nutraceuticals, and behavioral therapies). Regarding non-invasive neuromodulation, we selected transcranial magnetic stimulation, supraorbital nerve stimulation, transcranial direct current stimulation, non-invasive vagal nerve stimulation, and caloric vestibular stimulation. For nutraceuticals, we selected Feverfew, Butterbur, Riboflavin, Magnesium, and Coenzyme Q10. Finally, for behavioral approaches, we selected biofeedback, cognitive behavioral therapy, relaxation techniques, mindfulness-based therapy, and acceptance and commitment therapy. These approaches are increasingly seen as a valid treatment option in headache management, especially for patients with medication overuse or contraindications to drug treatment. However, further investigations are needed to consider the effectiveness of these approaches also with respect to the long-term effects.

Updated management of occipital nerve stimulator lead migration: case report of a technical challenge

Electrode migration is a challenge, even with adequate anchoring techniques, due to the high mechanical stress on components of occipital nerve stimulation (ONS) for headache disorders. When a lead displacement of an ONS implant is diagnosed, there are currently different approaches described for its management. Nevertheless current neuromodulation devices are designed like a continuum of components without any intermediate connector, and if a lead displacement is diagnosed, the solution is the complete removal of the electrode from its placement, and its repositioning through an ex-novo procedure. The described technique can allow ONS leads to be revised while minimizing the need to reopen incisions over the IPG, thus improving patients' intraoperative and postoperative discomfort, shortening surgical time and medical costs, reasonably reducing the incidence of infective postoperative complications.

Mapping Assessments Instruments for Headache Disorders against the ICF Biopsychosocial Model of Health and Disability

Headache disorders have a strong impact on sufferers’ lives. However, the “content” of assessment instruments addressing concepts, such as disability and quality of life (QoL), has not comprehensively been addressed. We searched SCOPUS for research papers in which outcome measures were used in adult populations of patients with migraine, tension-type headache (TTH), and cluster headache (CH). The content of single instruments was then mapped against the International Classification of Functioning, Disability, and Health. A total of 150 papers and 26 instruments were included: 15 addressed disability or impact, two addressed work-related difficulties, and nine addressed QoL. Few instruments were commonly used across the conditions and covered domains of functioning were impact on daily life activities, homework, school, and work-related tasks, leisure time, informal and family relations, pain, emotional difficulties, energy level, and impulse control. Most of the research is based on instruments that were developed for migraine, which is critical for CH, and the impact of headache disorders on work-related activities is poorly acknowledged. Further research is needed to expand the scope of headaches impact on daily life activities, and on environmental factors relevant to headache disorders to raise knowledge on the less represented areas, e.g., TTH impact.

Anodal transcranial direct current stimulation in chronic migraine and medication overuse headache: A pilot double-blind randomized sham-controlled trial

OBJECTIVES

Little evidence is available on the role of transcranial direct current stimulation (tDCS) in patients affected by chronic migraine (CM) and medication overuse headache (MOH). We aim to investigate the effects of tDCS in patients with CM and MOH as well as its role on brain activity.

METHODS

Twenty patients with CM and MOH were hospitalized for a 7-day detoxification treatment. Upon admission, patients were randomly assigned to anodal tDCS or sham stimulation delivered over the primary motor cortex contralateral to the prevalent migraine pain side every day for 5 days. Clinical data were recorded at baseline (T0), after 1 month (T2) and 6 months (T3). EEG recording was performed at T0, at the end of the tDCS/Sham treatment, and at T2.

RESULTS

At T2 and T3, we found a significant reduction in monthly migraine days (p = 0.001), which were more pronounced in the tDCS group when compared to the sham group (p = 0.016). At T2, we found a significant increase of alpha rhythm in occipital leads, which was significantly higher in tDCS group when compared to sham group.

CONCLUSIONS

tDCS showed adjuvant effects to detoxification in the management of patients with CM and MOH. The EEG recording showed a significant potentiation of alpha rhythm, which may represent a correlate of the underlying changes in cortico-thalamic connections.

SIGNIFICANCE

This study suggests a possible role for tDCS in the treatment of CM and MOH. The observed clinical improvement is coupled with a potentiation of EEG alpha rhythm.

Chronic Cluster Headache Update and East-West Comparisons: Focusing on Clinical Features, Pathophysiology, and Management

PURPOSE OF REVIEW

This review provides an update on chronic cluster headache (CH) focusing on clinical features, pathophysiology, and management as well as comparisons between Eastern and Western populations.

RECENT FINDINGS

Chronic CH in Eastern populations was relatively rare, compared to that in Western populations. Lacrimation and/or conjunctival injection is the most frequently reported cranial autonomic symptom, and visual aura is predominant in chronic CH patients. Neuroimaging evidence in both ethnic groups suggests that CH pathophysiology involves the hypothalamus and pain-modulatory areas, with dynamic alternations between CH episodes. Recent evidence indicates that midbrain dopaminergic systems may participate in CH chronicity. Noteworthy advances have emerged in neuromodulatory therapies for chronic CH, but treatment with calcitonin gene-related peptide (CGRP) monoclonal antibodies has been unsuccessful. Recent evidence shows divergence of chronic CH between Eastern and Western populations. Neuromodulatory therapies but not CGRP inhibition is effective in this intractable patient group.

Migraine as a Cortical Brain Disorder

PURPOSE

Migraine is an exclusively human chronic disorder with ictal manifestations characterized by a multifaceted clinical complexity pointing to a cerebral cortical involvement. The present review is aimed to cover the clinical, neuroimaging, and neurophysiological literature on the role of the cerebral cortex in migraine pathophysiology.

OVERVIEW

Converging clinical scenarios, advanced neuroimaging data, and experimental neurophysiological findings, indicate that fluctuating excitability, plasticity, and metabolism of cortical neurons represent the pathophysiological substrate of the migraine cycle. Abnormal cortical responsivity and sensory processing coupled to a mismatch between the brain's energy reserve and workload may ignite the trigeminovascular system, leading to the migraine attack through the activation of subcortical brain trigeminal and extra-trigeminal structures, and driving its propagation and maintenance.

DISCUSSION

The brain cortex emerges as the crucial player in migraine, a disorder lying at the intersection between neuroscience and daily life. Migraine disorder stems from an imbalance in inhibitory/excitatory cortical circuits, responsible for functional changes in the activity of different cortical brain regions encompassing the neurolimbic-pain network, and secondarily allowing a demodulation of subcortical areas, such as hypothalamus, amygdala, and brainstem nuclei, in a continuous mutual crosstalk.

Galcanezumab for the prevention of cluster headache

INTRODUCTION

Cluster headache (CH) is among the worst painful conditions. The available therapies are scarce and not specific, leaving many patients unsatisfied because of poor efficacy and/or tolerability. Patients not responding to common treatments are offered semi-invasive and invasive procedures with uncertain results. Based on the current understanding of CH pathophysiology, new possible therapeutic approaches come from drugs interfering with Calcitonin Gene Related Peptide (CGRP).

AREAS COVERED

After summarizing the evidence for CGRP involvement in CH pathophysiology, we review the published literature (PubMed) and information (clinicaltrials.gov, EudraCT, EMA and FDA websites) regarding a novel anti-CGRP monoclonal antibody, Galcanezumab, its pharmacological properties, development, and evidence for the treatment of CH. Publications regarding other indications (migraine) are considered for completeness and safety/tolerability profile.

EXPERT OPINION

In one randomized clinical trial, Galcanezumab has proven to be effective and safe as a preventive treatment in episodic CH, with a favorable tolerability profile offering a potential new option in the therapeutic arsenal. Inefficacy of galcanezumab in chronic CH as well as the inefficacy of another monoclonal antibody against CGRP (fremanezumab) in both episodic and chronic CH question the scalability of the drug in CH management. Further, studies comparing galcanezumab to the current standard treatments are highly desirable.

Neuromodulation in headache and craniofacial neuralgia: guidelines from the Spanish Society of Neurology and the Spanish Society of Neurosurgery

INTRODUCTION

Numerous invasive and non-invasive neuromodulation devices have been developed and applied to patients with headache and neuralgia in recent years. However, no updated review addresses their safety and efficacy, and no healthcare institution has issued specific recommendations on their use for these 2 conditions.

METHODS

Neurologists from the Spanish Society of Neurology's (SEN) Headache Study Group and neurosurgeons specialising in functional neurosurgery, selected by the Spanish Society of Neurosurgery (SENEC), performed a comprehensive review of articles on the MEDLINE database addressing the use of the technique in patients with headache and neuralgia.

RESULTS

We present an updated review and establish the first set of consensus recommendations of the SEN and SENC on the use of neuromodulation to treat headache and neuralgia, analysing the current levels of evidence on its effectiveness for each specific condition.

CONCLUSIONS

Current evidence supports the indication of neuromodulation techniques for patients with refractory headache and neuralgia (especially migraine, cluster headache, and trigeminal neuralgia) selected by neurologists and headache specialists, after pharmacological treatment options are exhausted. Furthermore, we recommend that invasive neuromodulation be debated by multidisciplinary committees, and that the procedure be performed by teams of neurosurgeons specialising in functional neurosurgery, with acceptable rates of morbidity and mortality.

Remote Electrical Neuromodulation for the Acute Treatment of Migraine in Patients with Chronic Migraine: An Open-Label Pilot Study

INTRODUCTION

Remote electrical neuromodulation (REN) is a novel acute treatment of migraine. Upper arm peripheral nerves are stimulated to induce conditioned pain modulation (CPM)-an endogenous analgesic mechanism in which conditioning stimulation inhibits pain in remote body regions. The REN device (Nerivio^®, Theranica Bio-Electronics LTD., Israel) is FDA-authorized for acute treatment of migraine in adults who do not have chronic migraine. The current study assessed the consistency of response over multiple migraine attacks in people with chronic migraine who are typically characterized with severe pain intensity, high disability, and less robust response to triptans.

METHODS

This was an open-label, single-arm, dual-center study conducted on adults with chronic migraine. Participants underwent a 4-week treatment phase in which they treated their migraine headaches with the device for 45 min within 1 h of attack onset. Pain levels were recorded at baseline, 2 h, and 24 h post-treatment. Efficacy outcomes (pain relief and pain-free responses at 2 h, sustained pain relief and sustained pain-free responses at 24 h) focused on intra-individual consistency of response across multiple attacks, which was defined as response in at least 50% of the treatments.

RESULTS

Forty-two participants were enrolled, and 38 participants were evaluable for analyses; 73.7% (28/38) achieved pain relief at 2 h, 26.3% (10/38) were pain-free at 2 h, 84.4% (27/32) had sustained pain relief response at 24 h and 45.0% (9/20) had sustained pain relief response at 24 h in at least 50% of their treated attacks. The effects of REN on associated symptoms and improvement in function were also consistent. The incidence of device-related adverse events was low (1.8%).

CONCLUSIONS

REN used for a series of migraine attacks was effective and well tolerated across attacks. REN may offer a safe and effective non-pharmacological alternative for acute treatment in patients with chronic migraine.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04161807. Retrospectively registered on November 13, 2019.

No efficacy of transcranial direct current stimulation on chronic migraine with medication overuse: A double blind, randomised clinical trial

Background

Transcranial direct current stimulation was suggested to provide beneficial effects in chronic migraine, a condition often associated with medication overuse for which no long-term therapy is available.

Methods

We conducted a randomised controlled trial to assess long-term efficacy of transcranial direct current stimulation. Adults diagnosed with chronic migraine and medication overuse were assigned to receive in a 1:1:1 ratio anodal, cathodal, or sham transcranial direct current stimulation daily for five consecutive days, along with standardised drug withdrawal protocol. Primary outcome was 50% reduction of days of headache per month at 12 months. Co-secondary outcomes were 50% reduction of days of headache per month at 6 months, reduction of analgesic intake per month, and change in disability and quality of life, catastrophising, depression, state and trait anxiety, dependence attitude and allodynia intensity. Patients were not allowed to take any migraine prophylaxis drug for the entire study period.

Results

We randomly allocated 135 patients to anodal (44), cathodal (45), and sham (46) transcranial direct current stimulation. At 6 and 12 months, the percentage of reduction of days of headache and number of analgesics per month ranged between 48.5% and 64.7%, without differences between transcranial direct current stimulation (cathodal, anodal, or the results obtained from the two arms of treatment, anodal plus cathodal) and sham. Catastrophising attitude significantly reduced at 12 months in all groups. There was no difference for the other secondary outcomes.

Conclusions

Transcranial direct current stimulation did not influence the short and long-term course of chronic migraine with medication overuse after acute drug withdrawal. Behavioral and educational measures and support for patients’ pain management could provide long-term improvement and low relapse rate. Trial registration number NCT04228809

Development and Evaluation of a Screening Tool to Aid the Diagnosis of a Cluster Headache

Cluster headache (CH), a severe primary headache, is often misdiagnosed and mismanaged. The aim of this study was to develop and evaluate a screening tool to aid the diagnosis of CH. We developed a novel 12-item screening tool. This was comprised of four components: (1) images depicting headache pain; (2) pain descriptors; (3) key questions that could differentiate between CH and migraine; and (4) a visual analogue pain scale. The total possible questionnaire score ranged from 3-32. Patients with CH and migraines (control group) were recruited prospectively from a headache centre in the North of England, UK. Two-hundred and ninety-six patients were included in the study: 81 CH patients, 36 of which suffer with episodic CH and 45 with chronic CH; 215 migraine patients, 92 of which suffer with episodic migraine and 123 with chronic migraine. The mean questionnaire score was higher in CH patients versus migraine patients (28.4 versus 19.5). At a cut-off score of >25 out of 32, the screening tool had a sensitivity of 86.4% and a specificity of 92.0% in differentiating between CH and migraine. The screening tool could be a useful instrument to aid the diagnosis of a CH. The images depicting headache pain do not clearly discriminate between CH and migraine.

Consensus of the Hellenic Headache Society on the diagnosis and treatment of migraine

More than 0.6 million people suffer from disabling migraines in Greece causing a dramatic work loss, but only a small proportion of migraineurs attend headache centres, most of them being treated by non-experts. On behalf of the Hellenic Headache Society, we report here a consensus on the diagnosis and treatment of adult migraine that is based on the recent guidelines of the European Headache Federation, on the principles of Good Clinical Practice and on the Greek regulatory affairs. The purposes are three-fold: (1) to increase awareness for migraine in Greece; (2) to support Greek practitioners who are treating migraineurs; and (3) to help Greek migraineurs to get the most appropriate treatment. For mild migraine, symptomatic treatment with high dose simple analgesics is suggested, while for moderate to severe migraines triptans or non-steroidal anti-inflammatory drugs, or both, should be administered following an individually tailored therapeutic strategy. A rescue acute treatment option should always be advised. For episodic migraine prevention, metoprolol (50–200 mg/d), propranolol (40–240 mg/d), flunarizine (5–10 mg/d), valproate (500–1800 mg/d), topiramate (25–100 mg/d) and candesartan (16–32 mg/d) are the drugs of first choice. For chronic migraine prevention topiramate (100-200 mg/d), valproate (500–1800 mg/d), flunarizine (5–10 mg/d) and venlafaxine (150 mg/d) may be used, but the evidence is very limited. Botulinum toxin type A and monoclonal antibodies targeting the CGRP pathway (anti-CGRP mAbs) are recommended for patients suffering from chronic migraine (with or without medication overuse) who failed or did not tolerate two previous treatments. Anti-CGRP mAbs are also suggested for patients suffering from high frequency episodic migraine (≥8 migraine days per month and less than 14) who failed or did not tolerate two previous treatments.

Device review: Pulsante™ sphenopalatine ganglion microstimulator

Cluster headache (CH) is a primary headache disorder. The use of neuromodulation in treatment of CH is well documented. The sphenopalatine ganglion (SPG) has long been a target for management of CH. Intervention at the level of the SPG can interrupt the trigemino-autonomic reflex, which mediates CH pain. The Pulsante system is the only device on the market created for SPG stimulation. The Pulsante device consists of the device body, a lead with six stimulating electrodes placed in the pterygopalatine fossa, and a fixation plate to allow anchoring of the device to the maxilla. Stimulation is administered via a patient-controlled handheld remote control held over the cheek. SPG stimulation is an important treatment option for CH patients.

Neurostimulation methods in the treatment of chronic pain

The goal of this narrative review was to give an up-to-date overview of the peripheral and central neurostimulation methods that can be used to treat chronic pain. Special focus has been given to three pain conditions: neuropathic pain, nociplastic pain and primary headaches. Both non-invasive and invasive techniques are briefly presented together with their pain relief potentials. For non-invasive stimulation techniques, data concerning transcutaneous electrical nerve stimulation (TENS), transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), remote electrical neuromodulation (REN) and vagus nerve stimulation (VNS) are provided. Concerning invasive stimulation techniques, occipital nerve stimulation (ONS), vagus nerve stimulation (VNS), epidural motor cortex stimulation (EMCS), spinal cord stimulation (SCS) and deep brain stimulation (DBS) are presented. The action mode of all these techniques is only partly understood but can be very different from one technique to the other. Patients' selection is still a challenge. Recent consensus-based guidelines for clinical practice are presented when available. The development of closed-loop devices could be of interest in the future, although the clinical benefit over open loop is not proven yet.

More Attacks and Analgesic Use in Old Age: Self-Reported Headache Across the Lifespan in a German Sample

Background: Reliable population-based data on the prevalence and characteristics of primary headache across the lifespan are essential. However, robust data are lacking.

Methods: We utilized questionnaire data from a random general population sample in Germany, that comprised 2,478 participants aged ≥14 years. A standardized questionnaire addressing headache and headache treatment was filled in during the face-to-face survey.

Results: The 6-month prevalence of self-reported headache in the total sample amounted to 39.0% (known diagnosis of migraine 7.2%; tension-type headache 12.4%; another diagnosis or unknown diagnosis 23.4%). Age-specific prevalence rates were 37.9% (14–34 years), 44.6% (35–54 years), 38.5% (55–74 years), and 26.9% (≥75 years). Compared to age group 14–34, participants aged 35–54 were more (OR = 1.29, 95%-CI 1.05–1.60, p = 0.018) and those aged ≥75 were less (OR = 0.55, 95%-CI 0.40–0.76, p < 0.001) likely to have any headache. Of the participants with headache, 79.5% reported headache on <4 days per month, 15.6% on 4–14 days per month and 4.9% on >14 days per month. The frequency of headache did not differ significantly between age groups in men [χ(3, N = 384)2 = 1.45, p > 0.05], but in women [χ(3, N = 651)2 = 21.57, p < 0.001]: women aged ≥75 years were over-represented in the group reporting 4–14 headache days per month. The analgesic use (days per month) differed significantly between age groups among participants with headache on <4 days per month and on >14 days per month: 1.8 (14–34 years), 2.5 (35–54 years), 3.2 (55–74 years), and 3.4 (≥75 years), respectively 7.9 (14–34 years), 11.4 (35–54 years), 18.4 (55–74 years), and 22.8 (≥75 years).

Conclusions: In general, the prevalence of headache decreases with age. However, older women suffer from more frequent attacks and older participants take analgesics on more days per month than younger participants. This might put them at risk of medication overuse which may lead to medication overuse headache. More research is needed to understand these specifics in headache frequency and treatment behavior in older people.

Effects of Non-invasive Brain Stimulation on Headache Intensity and Frequency of Headache Attacks in Patients With Migraine: A Systematic Review and Meta-Analysis

BACKGROUND

Non-invasive brain stimulation (NIBS) techniques such as repetitive transcranial magnetic stimulation (rTMS), as well as transcranial direct current stimulation (tDCS) electrically stimulate the brain and modify brain activity to suppress pain. This method is emerging as a potential clinical intervention against migraine.

OBJECTIVE

To quantitatively review the efficacy of rTMS and tDCS in randomized controlled trials (RCTs) in modifying headache intensity and frequency of headache attacks in patients suffering from migraine.

METHODS

We searched 5 databases: PubMed, EMBASE, Web of Science, Cochrane Library, and Scopus for articles from January 2000 to September 2018. Any RCT regarding the efficacy on rTMS and tDCS on patients with migraine, was considered to be included. A random effects meta-analysis was performed to pool effect sizes of outcomes related to headache intensity or frequency of headache attacks. The methodological quality of the included RCTs was assessed using the Physiotherapy Evidence Database scale.

RESULTS

Nine RCTs with 276 participants in total (experimental group [EG] = 149; control group [CG] = 127) were included in this review. Five included articles used rTMS (EG = 81; CG = 80), and 4 used tDCS (EG = 68; CG = 47). Meta-analysis of excitatory primary motor cortex (M1) stimulation showed significant effects on reducing headache intensity in patients with migraine (Hedges' g = -0.94; 95% CI, -1.28 to -0.59; P < .001, I²  = 18.39%) with a large effect size. Meta-analysis of excitatory M1 stimulation showed significant effects on reducing frequency of headache attacks in patients with migraine, with a large effect size (Hedges' g = -0.88; 95% CI, -1.38 to -0.38; P = .001, I²  = 57.15%). Excitatory dorsolateral prefrontal cortex stimulation showed a significant effect on the headache intensity in patients with migraine (Hedges' g = -1.14; 95% CI, -2.21 to -0.07; P = .04, I²  = 61.86%) with a large effect size. However, reductions of frequency of headache attacks was not significant.

LIMITATIONS

Potential differential effects of rTMS and tDCS, various sham methods, and potential overlapping headache disorders among included subjects may affect the estimation of effect sizes.

CONCLUSION

Excitatory NIBS of the M1 is likely to reduce headache intensity and the frequency of headache attacks in patients with migraine.

Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache

INTRODUCTION

This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache.

DEVELOPMENT

Various medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients' quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available.

CONCLUSIONS

These results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored.

Occipital nerve stimulation for non-migrainous chronic headaches: a systematic review protocol

BACKGROUND

Defined as a headache lasting at least 15 days per month, chronic headache is reported by 3% of the general population, and a substantial proportion of them are refractory to current therapies. Occipital nerve stimulation (ONS) is a treatment option, but is still considered as a last resort treatment especially because of its invasive nature and the cost associated. Some reviews reported a limited efficacy of ONS for the treatment of migraines, with a high risk of complications. However, results reporting its efficacy and safety on other headache disorders are unclear. The aim of this review is to assess the efficacy and safety of ONS in regards to non-migrainous chronic headaches.

METHODS

We will conduct a systematic review and meta-analysis of studies evaluating the use of ONS in comparison to sham stimulation or the best available treatment in patients with chronic headache. MEDLINE, CINHAL, EMBASE, PsycINFO, ECRI Institute Library, WIKISTIM, the Cochrane Library databases, and clinical trial registries will be searched for eligible studies. The review will include adult patients diagnosed with chronic headache excluding migraine. Two independent reviewers will process to the screening of studies according to titles, abstracts, and then full texts. The primary outcome is the overall reduction of head pain severity. The secondary outcomes are rates of reduction in the severity of head pain, headache frequency, and duration, use of medication, impairment, quality of life, healthcare utilization, return to work, and adverse events. Extracted data will include patients' and procedure characteristics, details on comparative treatment or sham, and clinical outcomes. The risk of bias of the studies will be also independently assessed using the Cochrane risk of bias tools.

DISCUSSION

This systematic review will allow us to better evaluate the potential role of ONS for the treatment of patients with chronic headache that are refractory to less invasive therapies. It will help to determine the degree of safety of ONS. Moreover, it will help to design and conduct future randomized controlled trials focused on patients who may better respond to such treatment.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019121623.