Success, failure, and putative mechanisms in hypothalamic stimulation for drug-resistant chronic cluster headache

Transition of cluster headache: Depicting side-changing attacks as a chronic trait in an interview-based follow-up study

BACKGROUND

Cluster headache presents in an episodic and chronic form, between which patients can convert during the course of disease. We aimed to quantify the rate of cluster headache patients changing phenotype within one and five years and investigate the earlier proposed association between chronification and having side-shifting attacks.

METHODS

In total, 430 cluster headache patients well-characterized according to current International Classification of Headache Disorders criteria, who were all participants in a prior transition-study, were re-interviewed in an observational, retrospective, cross-sectional follow-up study design at the Danish Headache Center.

RESULTS

The transition rate for the whole cohort was 6.5% within one year and 19.8% within five years. The risk of becoming chronic if episodic was 4.0% within one year and 12.3% within five years. For conversion from chronic to episodic, the corresponding risk was 11.1% and 25.0%, respectively. Alterations in attack-side were reported in 32% of all chronic patients, generating an odds ratio of 2.24 of being chronic as opposed to episodic if experiencing side-shifting attacks.

CONCLUSIONS

A higher transition rate since the original cross-sectional study demonstrates cluster headache as a non-static condition. Identifying a risk of transition within one and five years, based on current phenotype along with high odds of being chronic when experiencing a shift of attack-side, offers a valuable clinical compass in the dialogue with the patient.

Association of Clinical and Neuroanatomic Factors With Response to Ventral Tegmental Area DBS in Chronic Cluster Headache

BACKGROUND AND OBJECTIVES

Deep brain stimulation (DBS) of the ventral tegmental area (VTA) is a surgical treatment option for selected patients with refractory chronic cluster headache (CCH). We aimed to identify clinical and structural neuroimaging factors associated with response to VTA DBS in CCH.

METHODS

This prospective observational cohort study examines consecutive patients with refractory CCH treated with VTA DBS by a multidisciplinary team in a single tertiary neuroscience center as part of usual care. Headache diaries and validated questionnaires were completed at baseline and regular follow-up intervals. All patients underwent T1-weighted structural MRI before surgery. We compared clinical features using multivariable logistic regression and neuroanatomic differences using voxel-based morphometry (VBM) between responders and nonresponders.

RESULTS

Over a 10-year period, 43 patients (mean age 53 years, SD 11.9), including 29 male patients, with a mean duration of CCH 12 years (SD 7.4), were treated and followed up for at least 1 year (mean follow-up duration 5.6 years). Overall, there was a statistically significant improvement in median attack frequency from 140 to 56 per month (Z = -4.95, p < 0.001), attack severity from 10/10 to 8/10 (Z = -4.83, p < 0.001), and duration from 110 to 60 minutes (Z = -3.48, p < 0.001). Twenty-nine (67.4%) patients experienced ≥50% improvement in attack frequency and were therefore classed as responders. There were no serious adverse events. The most common side effects were discomfort or pain around the battery site (7 patients) and transient diplopia and/or oscillopsia (6 patients). There were no differences in demographics, headache characteristics, or comorbidities between responders and nonresponders. VBM identified increased neural density in nonresponders in several brain regions, including the orbitofrontal cortex, anterior cingulate cortex, anterior insula, and amygdala, which were statistically significant (p < 0.001).

DISCUSSION

VTA DBS showed no serious adverse events, and, although there was no placebo control, was effective in approximately two-thirds of patients at long-term follow-up. This study did not reveal any reliable clinical predictors of response. However, nonresponders had increased neural density in brain regions linked to processing of pain and autonomic function, both of which are prominent in the pathophysiology of CCH.

Ten-Year Durability of Hypothalamic Deep Brain Stimulation in Treatment of Chronic Cluster Headaches: A Case Report and Literature Review

Chronic cluster headache (CCH) is a debilitating primary headache that causes excruciating pain without remission. Various medical and surgical treatments have been implemented over the years, yet many provide only short-term relief. Deep brain stimulation (DBS) is an emerging treatment alternative that has been shown to dramatically reduce the intensity and frequency of headache attacks. However, reports of greater than 10-year outcomes after DBS for CCH are scant. Here, we report the durability of DBS in the posterior inferior hypothalamus after 10 years on a patient with CCH. Our patient experienced an 82% decrease in the frequency of headaches after DBS, which was maintained for over 10 years. The side effects observed included depression, irritability, anxiety, and dizziness, which were alleviated by changing programming settings. In the context of current literature, DBS shows promise for long-term relief of cluster headaches when other treatments fail.

Deep Brain Stimulation for Chronic Cluster Headaches: A Systematic Review and Meta-Analysis

BACKGROUND

Chronic cluster headache (CCH) is a severe and debilitating sub-type of trigeminal autonomic cephalalgia that can be resistant to medical management and associated with significant impairment in quality of life. Studies of deep brain stimulation (DBS) for CCH have provided promising results but have not been assessed in a comprehensive systematic review/meta-analysis.

OBJECTIVE

The objective was to perform a systematic literature review and meta-analysis of patients with CCH treated with DBS to provide insight on safety and efficacy.

METHODS

A systematic review and meta-analysis were performed according to PRISMA 2020 guidelines. 16 studies were included in final analysis. A random-effects model was used to meta-analyze data.

RESULTS

Sixteen studies reported 108 cases for data extraction and analysis. DBS was feasible in >99% of cases and was performed either awake or asleep. Meta-analysis revealed that the mean difference in headache attack frequency and headache intensity after DBS were statistically significant (p < 0.0001). Utilization of microelectrode recording was associated with statistically significant improvement in headache intensity postoperatively (p = 0.006). The average overall follow-up period was 45.4 months and ranged from 1 to 144 months. Death occurred in <1%. The rate of major complications was 16.67%.

CONCLUSIONS

DBS for CCHs is a feasible surgical technique with a reasonable safety profile that can be successfully performed either awake or asleep. In carefully selected patients, approximately 70% of patients achieve excellent control of their headaches.

Preventive treatment of refractory chronic cluster headache: systematic review and meta-analysis

BACKGROUND

Preventive treatment for refractory chronic cluster headache (rCCH) is challenging and many therapies have been tried.

OBJECTIVE

To study what could be considered the therapy of choice in rCCH through a systematic review and meta-analysis.

METHODS

This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The protocol was registered in PROSPERO (ID CRD42021290983). A systematic search was performed in MEDLINE, Embase, Cochrane, clinicaltrials.gov, and the WHO's-International-Clinical-Trials-Registry-Platform. Studies on the preventive treatment for rCCH as defined by the European Headache Federation consensus statement were included. A meta-analysis of the pooled response rate was conducted for the different therapies.

RESULTS

Of 336 results, 45 were eligible for inclusion. Most articles studied the effect of neuromodulation as a preventive treatment for rCCH. The most studied neuromodulation technique was occipital nerve stimulation (ONS), with a pooled response rate in the meta-analysis of 57.3% (95% CI 0.481-0.665). Deep brain stimulation (DBS) was the second most studied treatment with a pooled response rate of 77.0% (95% CI 0.594-0.957). DBS results were more heterogeneous than ONS, which could be related to the different stimulation targets in DBS studies, and reported more serious adverse events than in ONS studies. The remaining therapies (anti-CGRP pathway drugs, warfarin, ketamine-magnesium infusions, serial occipital nerve blocks, clomiphene, onabotulinum toxin A, ketogenic diet, sphenopalatine ganglion radiofrequency or stimulation, vagus nerve stimulation, percutaneous bioelectric current stimulation, upper cervical cord stimulation, and vidian neurectomy) present weaker results or have less quality of evidence.

CONCLUSIONS

The results of this systematic review and meta-analysis suggest that ONS could be the first therapeutic strategy for patients with rCCH based on the current evidence.

Neuromodulation for Chronic Daily Headache

Purpose of Review

We reviewed the literature that explored the use of central and peripheral neuromodulation techniques for chronic daily headache (CDH) treatment.

Recent Findings

Although the more invasive deep brain stimulation (DBS) is effective in chronic cluster headache (CCH), it should be reserved for extremely difficult-to-treat patients. Percutaneous occipital nerve stimulation has shown similar efficacy to DBS and is less risky in both CCH and chronic migraine (CM). Non-invasive transcutaneous vagus nerve stimulation is a promising add-on treatment for CCH but not for CM. Transcutaneous external trigeminal nerve stimulation may be effective in treating CM; however, it has not yet been tested for cluster headache. Transcranial magnetic and electric stimulations have promising preventive effects against CM and CCH.

Summary

Although the precise mode of action of non-invasive neuromodulation techniques remains largely unknown and there is a paucity of controlled trials, they should be preferred to more invasive techniques for treating CDH.

Neurostimulation Treatment in Chronic Cluster Headache-a Narrative Review

PURPOSE OF REVIEW

In this narrative review, the current literature on neurostimulation methods in the treatment of chronic cluster headache is evaluated. These neurostimulation methods include deep brain stimulation, vagus nerve stimulation, greater occipital nerve stimulation, sphenopalatine ganglion stimulation, transcranial magnetic stimulation, transcranial direct current stimulation, supraorbital nerve stimulation, and cervical spinal cord stimulation.

RECENT FINDINGS

Altogether, only nVNS and SPG stimulation are supported by at least one positive sham-controlled clinical trial for preventive and acute attack (only SPG stimulation) treatment. Other clinical trials either did not control at all or controlled by differences in the stimulation technique itself but not by a sham-control. Case series report higher responder rates. The evidence for these neurostimulation methods in the treatment of chronic cluster headache is poor and in part contradictive. However, except deep brain stimulation, tolerability and safety of these methods are good so that in refractory situations application might be justified in individual cases.

Deep brain stimulation of the brainstem

Deep brain stimulation (DBS) of the subthalamic nucleus, pallidum, and thalamus is an established therapy for various movement disorders. Limbic targets have also been increasingly explored for their application to neuropsychiatric and cognitive disorders. The brainstem constitutes another DBS substrate, although the existing literature on the indications for and the effects of brainstem stimulation remains comparatively sparse. The objective of this review was to provide a comprehensive overview of the pertinent anatomy, indications, and reported stimulation-induced acute and long-term effects of existing white and grey matter brainstem DBS targets. We systematically searched the published literature, reviewing clinical trial articles pertaining to DBS brainstem targets. Overall, 164 studies describing brainstem DBS were identified. These studies encompassed 10 discrete structures: periaqueductal/periventricular grey (n = 63), pedunculopontine nucleus (n = 48), ventral tegmental area (n = 22), substantia nigra (n = 9), mesencephalic reticular formation (n = 7), medial forebrain bundle (n = 8), superior cerebellar peduncles (n = 3), red nucleus (n = 3), parabrachial complex (n = 2), and locus coeruleus (n = 1). Indications for brainstem DBS varied widely and included central neuropathic pain, axial symptoms of movement disorders, headache, depression, and vegetative state. The most promising results for brainstem DBS have come from targeting the pedunculopontine nucleus for relief of axial motor deficits, periaqueductal/periventricular grey for the management of central neuropathic pain, and ventral tegmental area for treatment of cluster headaches. Brainstem DBS has also acutely elicited numerous motor, limbic, and autonomic effects. Further work involving larger, controlled trials is necessary to better establish the therapeutic potential of DBS in this complex area.

Cluster headache and TACs: state of the art

Cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks (including SUNCT and SUNA), and hemicrania continua (HC) compose the group of trigeminal autonomic cephalalgias (TACs). Here, we review the recent advances in the field and summarize the current knowledge about the origin of these headaches. Similar to the other primary headaches, the pathogenesis is still much obscure. However, advances are being made in both animal models and humans studies. Three structures clearly appear to be crucial in the pathophysiology of TACs: the trigeminal nerve, the facial parasympathetic system, and the hypothalamus. The physiologic and pathologic functioning of each of these elements and their interactions is being progressively clarified, but critical questions are still open.

Occipital nerve stimulation and deep brain stimulation for refractory cluster headache: a prospective analysis of efficacy over time

OBJECTIVE

Occipital nerve stimulation (ONS) and deep brain stimulation (DBS) are widely used surgical treatments for chronic refractory cluster headache (CH). However, there is little literature regarding long-term follow-up of these treatments.

METHODS

The authors describe two prospective cohorts of patients with refractory CH treated with ONS and DBS and compare preoperative to postoperative status at 6 and 12 months after the surgery and at final follow-up. Efficacy analysis using objective and subjective variables is reported, as well as medication reduction and complications.

RESULTS

The ONS group consisted of 13 men and 4 women, with a median age of 44 years (range 31-61 years). The median number of attacks per week (NAw) before surgery was 28 (range 7-70), and the median follow-up duration was 48 months. The DBS group comprised 5 men and 2 women, with a median age of 50 years (range 29-64 years). The median NAw before surgery was 56 (range 14-140), and the median follow-up was 36 months. The NAw and visual analog scale score were significantly reduced for the ONS and DBS groups after surgery. However, while all the patients from the DBS group were considered responders at final follow-up, with more than 85% being satisfied with the treatment, approximately 29% of initial responders to ONS became resistant by the final follow-up (p = 0.0253).

CONCLUSIONS

ONS is initially effective as a treatment for refractory CH, although a trend toward loss of efficacy was observed. No clear predictors of good clinical response were found in the present study. Conversely, DBS appears to be effective and provide a more stable clinical response over time with an acceptable rate of surgical complications.

Understanding Cluster Headache Using Magnetic Resonance Imaging

Cluster headache is an excruciating pain syndrome characterized by unilateral head pain attacks, lasting between 15 and 180 min, accompanied by marked ipsilateral cranial autonomic symptoms, such as lacrimation and conjunctival injection. Despite important insights provided by neuroimaging studies and deep brain stimulation findings, the pathophysiology of cluster headache and its pathways of chronicization are still elusive. In this mini-review, we will provide an overview of the functional and structural neuroimaging studies in episodic and chronic cluster headache conditions conducted to clarify the underlying pathophysiology.

Effect of Infusion of Calcitonin Gene-Related Peptide on Cluster Headache Attacks: A Randomized Clinical Trial

Importance

Signaling molecule calcitonin gene-related peptide (CGRP) induces migraine attacks and anti-CGRP medications abort and prevent migraine attacks. Whether CGRP provokes cluster headache attacks is unknown.

Objective

To determine whether CGRP induces cluster headache attacks in episodic cluster headache in active phase, episodic cluster headache in remission phase, and chronic cluster headache.

Design, Setting, and Participants

A randomized, double-blind, placebo-controlled, 2-way crossover study set at the Danish Headache Center, Rigshospitalet Glostrup, in Denmark. Analyses were intent to treat. Inclusion took place from December 2015 to April 2017. Inclusion criteria were diagnosis of episodic/chronic cluster headache, patients aged 18 to 65 years, and safe contraception in women. Exclusion criteria were a history of other primary headache (except episodic tension-type headache <5 days/mo), individuals who were pregnant or nursing; cardiovascular, cerebrovascular, or psychiatric disease; and drug misuse.

Interventions

Thirty-seven patients with cluster headaches received intravenous infusion of 1.5 μg/min of CGRP or placebo over 20 minutes on 2 study days.

Main Outcomes and Measures

Difference in incidence of cluster headache-like attacks, difference in area under the curve (AUC) for headache intensity scores (0 to 90 minutes), and difference in time to peak headache between CGRP and placebo in the 3 groups.

Results

Of 91 patients assessed for eligibility, 32 patients (35.2%) were included in the analysis. The mean (SD) age was 36 (10.7) years (range, 19-60 years), and the mean weight was 78 kg (range, 53-100 kg). Twenty-seven men (84.4%) completed the study. Calcitonin gene-related peptide induced cluster headache attacks in 8 of 9 patients in the active phase (mean, 89%; 95% CI, 63-100) compared with 1 of 9 in the placebo group (mean, 11%; 95% CI, 0-37) (P = .05). In the remission phase, no patients with episodic cluster headaches reported attacks after CGRP or placebo. Calcitonin gene-related peptide-induced attacks occurred in 7 of 14 patients with chronic cluster headaches (mean, 50%; 95% CI, 20-80) compared with none after placebo (P = .02). In patients with episodic active phase, the mean AUC from 0 to 90 minutes for CGRP was 1.903 (95% CI, 0.842-2.965), and the mean AUC from 0 to 90 minutes for the placebo group was 0.343 (95% CI, 0-0.867) (P = .04). In patients with chronic cluster headache, the mean AUC from 0 to 90 minutes for CGRP was 1.214 (95% CI, 0.395-2.033), and the mean AUC from 0 to 90 minutes for the placebo group was 0.036 (95% CI, 0-0.114) (P = .01). In the remission phase, the mean AUC from 0 to 90 minutes for CGRP was 0.187 (95% CI, 0-0.571), and the mean AUC from 0 to 90 minutes for placebo was 0.019 (95% CI, 0-0.062) (P > .99).

Conclusions and Relevance

Calcitonin gene-related peptide provokes cluster headache attacks in active-phase episodic cluster headache and chronic cluster headache but not in remission-phase episodic cluster headache. These results suggest anti-CGRP drugs may be effective in cluster headache management.

Trial Registration

ClinicalTrials.gov (NCT02466334).

Deep brain stimulation of chronic cluster headaches: Posterior hypothalamus, ventral tegmentum and beyond

OBJECTIVE

We present long-term follow-up results and analysis of stimulation sites of a prospective cohort study of six patients with chronic cluster headaches undergoing deep brain stimulation of the ipsilateral posterior hypothalamic region.

METHODS

The primary endpoint was the postoperative change in the composite headache severity score "headache load" after 12 months of chronic stimulation. Secondary endpoints were the changes in headache attack frequency, headache attack duration and headache intensity, quality of life measures at 12, 24, and 48 months following surgery. Stimulating contact positions were analysed and projected onto the steroetactic atlas of Schaltenbrand and Wahren.

RESULTS

There was a significant reduction of headache load of over 93% on average at 12 months postoperatively that persisted over the follow-up period of 48 months (p = 0.0041) and that was accompanied by a significant increase of reported quality of life measures (p = 0.03). Anatomical analysis revealed that individual stimulating electrodes were located in the red nucleus, posterior hypothalamic region, mesencephalic pretectal area and centromedian nucleus of the thalamus.

CONCLUSIONS

Our findings confirming long-term effectiveness of deep brain stimulation for chronic cluster headaches suggest that the neuroanatomical substrate of deep brain stimulation-induced headache relief is probably not restricted to the posterior hypothalamic area but encompasses a more widespread area.

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.

Deep brain stimulation of posterior hypothalamic area for cluster headache

Background:

Deep brain stimulation of the posterior hypothalamic area is one of the neuromodulation treatments used for chronic cluster headache, but the number of published patients remains low.

Aim:

The aim of this article was to present the retrospective results of 12 consecutive chronic cluster headache patients treated with deep brain stimulation at Helsinki University Hospital.

Materials and Methods:

All chronic cluster headache patients treated with deep brain stimulation between 2004 and 2012 were included in the study. Patients were interviewed and their hospital files analyzed. Treatment effect was classified as good, partial, or no effect.

Results:

Of the 12 patients, four had a good treatment effect, five had partial, and three had no effect of deep brain stimulation. In contrast to previous studies, our patients reported an almost immediate benefit after the onset of stimulation.

Conclusions:

Deep brain stimulation provides clinically meaningful benefit to a subgroup of chronic cluster headache patients.

Deep brain stimulation for trigeminal autonomic cephalalgias

Introduction: Deep brain stimulation (DBS) of the posterior hypothalamic region (pHyr) has been shown to be efficacious for more than a half of patients suffering from trigeminal autonomic cephalalgias (TACs); nonetheless, controversies about the mechanisms of action and the actual site of stimulation have arisen in recent years.Areas covered: Firstly, a review of the most recent literature on the subject is presented, stressing the critical points that could, in the future, make a difference for optimal management of patients afflicted by these life-threating diseases. Hypothalamic functional anatomy, experimental data and pathophysiological hypotheses are reported.Expert commentary: About 32% of patients who underwent DBS for TACs are pain-free. The determination of the pHyr region seems to be crucial for the generation of pain attack in these pathologies, although other structures are involved in complex mechanisms and circuits that interact with each other. Neurophysiological data, combined with more advanced experimental models, are of primary importance regarding our understanding of what the real target is, and how to overcome the issue of refractory patients.

Therapeutic Approaches for the Management of Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgia (TAC) encompasses 4 unique primary headache types: cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms. They are grouped on the basis of their shared clinical features of unilateral headache of varying durations and ipsilateral cranial autonomic symptoms. The shared clinical features reflect the underlying activation of the trigeminal-autonomic reflex. The treatment for TACs has been limited and not specific to the underlying pathogenesis. There is a proportion of patients who are refractory or intolerant to the current standard medical treatment. From instrumental bench work research and neuroimaging studies, there are new therapeutic targets identified in TACs. Treatment has become more targeted and aimed towards the pathogenesis of the conditions. The therapeutic targets range from the macroscopic and structural level down to the molecular and receptor level. The structural targets for surgical and noninvasive neuromodulation include central neuromodulation targets: posterior hypothalamus and, high cervical nerves, and peripheral neuromodulation targets: occipital nerves, sphenopalatine ganglion, and vagus nerve. In this review, we will also discuss the neuropeptide and molecular targets, in particular, calcitonin gene-related peptide, somatostatin, transient receptor potential vanilloid-1 receptor, nitric oxide, melatonin, orexin, pituitary adenylate cyclase-activating polypeptide, and glutamate.

Cluster headache: present and future therapy

Cluster headache is characterized by severe, unilateral headache attacks of orbital, supraorbital or temporal pain lasting 15-180 min accompanied by ipsilateral lacrimation, rhinorrhea and other cranial autonomic manifestations. Cluster headache attacks need fast-acting abortive agents because the pain peaks very quickly; sumatriptan injection is the gold standard acute treatment. First-line preventative drugs include verapamil and carbolithium. Other drugs demonstrated effective in open trials include topiramate, valproic acid, gabapentin and others. Steroids are very effective; local injection in the occipital area is also effective but its prolonged use needs caution. Monoclonal antibodies against calcitonin gene-related peptide are under investigation as prophylactic agents in both episodic and chronic cluster headache. A number of neurostimulation procedures including occipital nerve stimulation, vagus nerve stimulation, sphenopalatine ganglion stimulation and the more invasive hypothalamic stimulation are employed in chronic intractable cluster headache.

Cluster headache

Cluster headache is an excruciating, strictly one-sided pain syndrome with attacks that last between 15 minutes and 180 minutes and that are accompanied by marked ipsilateral cranial autonomic symptoms, such as lacrimation and conjunctival injection. The pain is so severe that female patients describe each attack as worse than childbirth. The past decade has seen remarkable progress in the understanding of the pathophysiological background of cluster headache and has implicated the brain, particularly the hypothalamus, as the generator of both the pain and the autonomic symptoms. Anatomical connections between the hypothalamus and the trigeminovascular system, as well as the parasympathetic nervous system, have also been implicated in cluster headache pathophysiology. The diagnosis of cluster headache involves excluding other primary headaches and secondary headaches and is based primarily on the patient's symptoms. Remarkable progress has been achieved in developing effective treatment options for single cluster attacks and in developing preventive measures, which include pharmacological therapies and neuromodulation.

Optimal deep brain stimulation site and target connectivity for chronic cluster headache

OBJECTIVE

To investigate the mechanism of action of deep brain stimulation for refractory chronic cluster headache and the optimal target within the ventral tegmental area.

METHODS

Seven patients with refractory chronic cluster headache underwent high spatial and angular resolution diffusion MRI preoperatively. MRI-guided and MRI-verified electrode implantation was performed unilaterally in 5 patients and bilaterally in 2. Volumes of tissue activation were generated around active lead contacts with a finite-element model. Twelve months after surgery, voxel-based morphometry was used to identify voxels associated with higher reduction in headache load. Probabilistic tractography was used to identify the brain connectivity of the activation volumes in responders, defined as patients with a reduction of ≥30% in headache load.

RESULTS

There was no surgical morbidity. Average follow-up was 34 ± 14 months. Patients showed reductions of 76 ± 33% in headache load, 46 ± 41% in attack severity, 58 ± 41% in headache frequency, and 51 ± 46% in attack duration at the last follow-up. Six patients responded to treatment. Greatest reduction in headache load was associated with activation in an area cantered at 6 mm lateral, 2 mm posterior, and 1 mm inferior to the midcommissural point of the third ventricle. Average responders' activation volume lay on the trigeminohypothalamic tract, connecting the trigeminal system and other brainstem nuclei associated with nociception and pain modulation with the hypothalamus, and the prefrontal and mesial temporal areas.

CONCLUSIONS

We identify the optimal stimulation site and structural connectivity of the deep brain stimulation target for cluster headache, explicating possible mechanisms of action and disease pathophysiology.

The pathophysiology of episodic cluster headache: Insights from recent neuroimaging research

Background

Cluster headache is a disorder characterized by intermittent, severe unilateral head pain accompanied by cranial autonomic symptoms. Most cases of CH are episodic, manifesting as “in-bout” periods of frequent headache separated by month-to-year-long “out-of-bout” periods of remission. Previous imaging studies have implicated the hypothalamus and pain matrix in the pathogenesis of episodic CH. However, the pathophysiology driving the transition between in- and out-of-bout periods remains unclear.

Methods

The present study provides a narrative review of previous neuroimaging studies on the pathophysiology of episodic CH, addressing alterations in brain structures, metabolism, and structural and functional connectivity occurring between bout periods.

Results

Although the precise brain structures responsible for episodic CH are unknown, major roles are indicated for the posterior hypothalamus (especially in acute attacks), the pain neuromatrix with an emphasis on central descending pain modulation, and non-traditional pain processing networks including the occipital, cerebellar, and salience networks. These areas are potentially related to dynamic transitioning between in- and out-of-bout periods.

Conclusion

Recent progress in magnetic resonance imaging of episodic CH has provided additional insights into dynamic bout-associated structural and functional connectivity changes in the brain, especially in non-traditional pain processing network areas. These areas warrant future investigations as targets for neuromodulation in patients with CH.

Central and Peripheral Neural Targets for Neurostimulation of Chronic Headaches

PURPOSE OF REVIEW

Chronic headache sufferers are estimated to be around 3% of the population. These patients have a high disease burden. When prophylactic treatments have low efficacy and tolerability, patients are in need of alternative therapeutic strategies and options.

RECENT FINDINGS

In the last decade, a number of neuromodulation procedures have been introduced as treatment of chronic intractable headache patients when pharmacological treatments fail or are not well tolerated. Neurostimulation of peripheral and central nervous system has been carried out, and now, various non-invasive and invasive stimulation devices are available. Non-invasive neurostimulation options include vagus nerve stimulation, supraorbital stimulation and single-pulse transcranial magnetic stimulation; invasive procedures include occipital nerve stimulation, sphenopalatine ganglion stimulation and hypothalamic deep brain stimulation. In many cases, results supporting their use derive from open-label series and small controlled trial studies. Lack of adequate placebo hampers adequate randomized controlled trials. In this paper, we give an overview on the main neurostimulation procedures in terms of results and putative mechanism of cation.

Bout-associated intrinsic functional network changes in cluster headache: A longitudinal resting-state functional MRI study

Background Previous imaging studies on the pathogenesis of cluster headache (CH) have implicated the hypothalamus and multiple brain networks. However, very little is known regarding dynamic bout-associated, large-scale resting state functional network changes related to CH. Methods Resting-state functional magnetic resonance imaging data were obtained from CH patients and matched controls. Data were analyzed using independent component analysis for exploratory assessment of the changes in intrinsic brain networks and their relationship between in-bout and out-of-bout periods, as well as correlations with clinical observations. Results Compared to healthy controls, CH patients had functional connectivity (FC) changes in the temporal, frontal, salience, default mode, somatosensory, dorsal attention, and visual networks, independent of bout period. Compared to out-of-bout scans, in-bout scans showed altered FC in the frontal and dorsal attention networks. Lower frontal network FC correlated with longer duration of CH. Conclusions The present findings suggest that episodic CH with dynamic bout period shifts may involve bout-associated FC changes in multiple discrete cortical areas within networks outside traditional pain processing areas. Dynamic changes in FC in frontal and dorsal attention networks between bout periods could be important for understanding episodic CH pathophysiology.

Cluster headache and other TACs: Pathophysiology and neurostimulation options

BACKGROUND

The trigeminal autonomic cephalalgias (TACs) are highly disabling primary headache disorders. There are several issues that remain unresolved in the understanding of the pathophysiology of the TACs, although activation of the trigeminal-autonomic reflex and ipsilateral hypothalamic activation both play a central role. The discovery of the central role of the hypothalamus led to its use as a therapeutic target. After the good results obtained with hypothalamic stimulation, other peripheral neuromodulation targets were tried in the management of refractory cluster headache (CH) and other TACs.

METHODS

This review is a summary both of CH pathophysiology and of efficacy of the different neuromodulation techniques.

RESULTS

In chronic cluster headache (CCH) patients, hypothalamic deep brain stimulation (DBS) produced a decrease in attack frequency of more than 50% in 60% of patients. Occipital nerve stimulation (ONS) also elicited favorable outcomes with a reduction of more than 50% of attacks in around 70% of patients with medically intractable CCH. Stimulation of the sphenopalatine ganglion (SPG) with a miniaturized implanted stimulator produced a clinically significant improvement in 68% of patients (acute, preventive, or both). Vagus nerve stimulation (VNS) with a portable device used in conjunction with standard of care in CH patients resulted in a reduction in the number of attacks. DBS and ONS have been used successfully in some cases of other TACs, including hemicrania continua (HC) and short-lasting unilateral headache attacks (SUNHA).

CONCLUSIONS

DBS has good results, but it is a more invasive technique and can generate serious adverse events. ONS has good results, but frequent and not serious adverse events. SPG stimulation (SPGS) is also efficacious in the acute and prophylactic treatment of refractory cluster headache. At this moment, ONS and SPG stimulation techniques are recommended as first line therapy in refractory cluster patients. New recent non-invasive approaches such as the non-invasive vagal nerve stimulator (nVNS) have shown efficacy in a few trials and could be an interesting alternative in the management of CH, but require more testing and positive randomized controlled trials.

Deep brain stimulation in headache

BACKGROUND

Deep brain stimulation of the posterior hypothalamic area was first introduced in 2000 to treat drug-refractory chronic cluster headache (CH).

FINDINGS

So far, hypothalamic stimulation has been employed in 79 patients suffering from various forms of intractable short-lasting unilateral headache forms, mainly trigeminal autonomic cephalalgias. The majority were (88.6%) chronic CH, including one patient who suffered from symptomatic chronic CH-like attacks; the remaining were short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), one had paroxysmal hemicranias and one symptomatic trigeminal neuralgia. Overall, after a mean follow up of 2.2 years, 69.6% (55) hypothalamic-stimulated patients showed a ≥50% improvement.

CONCLUSIONS

These observations need confirmation in randomised, controlled trials. A key role of the posterior hypothalamic area in the pathophysiology of unilateral short-lasting headaches, possibly by regulating the duration rather than triggering the attacks, can be hypothesised. Because of its invasiveness, hypothalamic stimulation can be proposed only after other, less-invasive, neurostimulation procedures have been tried.

Long-term occipital nerve stimulation for drug-resistant chronic cluster headache

Introduction

Chronic cluster headache is rare and some of these patients become drug-resistant. Occipital nerve stimulation has been successfully employed in open studies to treat chronic drug-resistant cluster headache. Data from large group of occipital nerve stimulation-treated chronic cluster headache patients with long duration follow-up are advantageous.

Patients and methods

Efficacy of occipital nerve stimulation has been evaluated in an experimental monocentric open-label study including 35 chronic drug-resistant cluster headache patients (mean age 42 years; 30 men; mean illness duration: 6.7 years). The primary end-point was a reduction in number of daily attacks.

Results

After a median follow-up of 6.1 years (range 1.6–10.7), 20 (66.7%) patients were responders (≥50% reduction in headache number per day): 12 (40%) responders showed a stable condition characterized by sporadic attacks, five responders had a 60–80% reduction in headache number per day and in the remaining three responders chronic cluster headache was transformed in episodic cluster headache. Ten (33.3%) patients were non-responders; half of these have been responders for a long period (mean 14.6 months; range 2–48 months). Battery depletion (21 patients 70%) and electrode migration (six patients – 20%) were the most frequent adverse events.

Conclusions

Occipital nerve stimulation efficacy is confirmed in chronic drug-resistant cluster headaches even after an exceptional long-term follow-up. Tolerance can occur years after improvement.

Neurostimulation in the treatment of primary headaches

There is increasing interest in using neurostimulation to treat headache disorders. There are now several non-invasive and invasive stimulation devices available with some open-label series and small controlled trial studies that support their use. Non-invasive stimulation options include supraorbital stimulation (Cefaly), vagus nerve stimulation (gammaCore) and single-pulse transcranial magnetic stimulation (SpringTMS). Invasive procedures include occipital nerve stimulation, sphenopalatine ganglion stimulation and ventral tegmental area deep brain stimulation. These stimulation devices may find a place in the treatment pathway of headache disorders. Here, we explore the basic principles of neurostimulation for headache and overview the available methods of neurostimulation.

Ventral tegmental area deep brain stimulation for refractory chronic cluster headache

OBJECTIVE

To present outcomes in a cohort of medically intractable chronic cluster headache (CCH) patients treated with ventral tegmental area (VTA) deep brain stimulation (DBS).

METHODS

In an uncontrolled open-label prospective study, 21 patients (17 male; mean age 52 years) with medically refractory CCH were selected for ipsilateral VTA-DBS by a specialist multidisciplinary team including a headache neurologist and functional neurosurgeon. Patients had also failed or were denied access to occipital nerve stimulation within the UK National Health Service. The primary endpoint was improvement in the headache frequency. Secondary outcomes included other headache scores (severity, duration, headache load), medication use, disability and affective scores, quality of life (QoL) measures, and adverse events.

RESULTS

Median follow-up was 18 months (range 4-60 months). At the final follow-up point, there was 60% improvement in headache frequency (p = 0.007) and 30% improvement in headache severity (p = 0.001). The headache load (a composite score encompassing frequency, severity, and duration of attacks) improved by 68% (p = 0.002). Total monthly triptan intake of the group dropped by 57% posttreatment. Significant improvement was observed in a number of QoL, disability, and mood scales. Side effects included diplopia, which resolved in 2 patients following stimulation adjustment, and persisted in 1 patient with a history of ipsilateral trochlear nerve palsy. There were no other serious adverse events.

CONCLUSIONS

This study supports that VTA-DBS may be a safe and effective therapy for refractory CCH patients who failed conventional treatments.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that VTA-DBS decreases headache frequency, severity, and headache load in patients with medically intractable chronic cluster headaches.

Invasive occipital nerve stimulation for refractory chronic cluster headache: what evolution at long-term? Strengths and weaknesses of the method

Background

Invasive Occipital Nerve Stimulation (iONS) is a costly technique which appears effective in drug-refractory chronic cluster headache (drCCH) management. Available data on long-term effectiveness and safety of iONS in this indication are scarce, though they could be useful to neurologists and patients in daily practice. The purpose of this short report is to discuss the very long-term outcome of a drCCH cohort, including adverse events.

Findings

Previously, favourable results were obtained with iONS in 15 drCCH patients: 80 % were significantly improved and 60 % were pain free. We report here the very long-term follow-up (up to nine years) of 10 patients belonging to this cohort. Meanwhile 5 patients had to be definitively explanted because of device infection (3) or paresthesia intolerance (2). Four patients (40 %) evolved to an episodic form of CH. Six remained chronic but their attack frequency was decreased by 70 % on average. Intake of preventive drugs is still necessary in 80 % of patients. All patients needed at least one battery replacement.

Conclusions

Up to nine years after implantation, iONS is still effective in most patients with drCCH. Concomitant preventive drugs remain often necessary. Forty percent of patients reverse to episodic CH, possibly by natural history. iONS is not a benign procedure but device-related complications appear similar to those reported with other invasive neurostimulators.

Neuromodulation in cluster headache

Medically refractory chronic cluster headache (CH) is a severely disabling headache condition for which several surgical procedures have been proposed as a prophylactic treatment. None of them have been evaluated in controlled conditions, only open studies and case series being available. Destructive procedures (radiofrequency lesioning, radiosurgery, section) and microvascular decompression of the trigeminal nerve or the sphenopalatine ganglion (SPG) have induced short-term improvement which did not maintain on long term in most of the patients. They carried a high risk of complications, including severe sensory loss and neuropathic pain, and consequently should not be proposed in first intention.Deep brain stimulation (DBS), targeting the presumed CH generator in the retro-hypothalamic region or fibers connecting it, decreased the attack frequency >50 in 60 % of the 52 patients reported. Complications were infrequent: gaze disturbances, autonomic disturbances, and intracranial hemorrhage (2).Occipital nerve stimulation (ONS) was efficient (decrease of attack frequency >50 %) in about 70 % of the 60 patients reported, with a low risk of complications (essentially hardware related). Considering their respective risks, ONS should be proposed first and DBS only in case of ONS failure.New on-demand chronically implanted SPG stimulation seemed to be efficient to abort CH attacks in a pilot controlled trial, but its long-term safety needs to be further studied.

Response to deep brain stimulation in the lateral hypothalamic area in a rat model of obesity: in vivo assessment of brain glucose metabolism

PURPOSE

To investigate changes in glucose brain metabolism after deep brain stimulation (DBS) in the lateral hypothalamic area (LHA) in a rat model of obesity.

PROCEDURES

Ten obese male Zucker rats were divided into two groups: LHA-control and LHA-DBS. Concentric bipolar platinum-iridium electrodes were implanted bilaterally. After 7 days, DBS was applied for 15 days. Weight and food and water intake were monitored. 2-Deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) PET-CT imaging studies were performed the day after the end of DBS. Differences in glucose uptake between the groups were assessed with statistical parametric mapping.

RESULTS

A difference in weight gain of 3.19 percentage points was found between groups. Average food consumption during the first 15 days was lower in DBS-treated animals than in non-stimulated animals. DBS increased metabolism in the mammillary body, subiculum-hippocampal area, and amygdala, while a decrease in metabolism was recorded in the thalamus, caudate, temporal cortex, and cerebellum.

CONCLUSIONS

DBS produced significant changes in brain regions associated with the control of food intake and the brain reward system. DBS seems to normalize the impaired hippocampal functioning that has been described in obese rats. The smaller weight gain in the DBS group suggests that this technique could be considered an option for the treatment of obesity.

Alcohol percutaneous neurolysis of the sphenopalatine ganglion in the management of refractory cranio-facial pain

INTRODUCTION

The sphenopalatine ganglion (SPN) has been proven to be involved in various types of facial pain syndromes. Management of these cranio-facial pain syndromes can be challenging, and existing specific treatments are sometimes inefficient and may fail. The purpose of this study is to describe and evaluate alcohol SPN in the management of cranio-facial pain.

METHODS

Forty-two patients suffering from refractory facial pain who underwent 58 consecutive SPN were included in this study between 2000 and 2013. Patients were divided into three groups: group "cluster headache" (CH), group "persistent idiopathic facial pain" (PFIP), and group "Other". Pain was assessed using Visual Analogue Scale scores (measured immediately before and after procedure and at regular intervals following the procedure). Alcohol SPN was considered to be effective when pain relief was equal to or greater than 50 % and lasting for at least 1 month. All procedures were realized ambulatory under CT guidance and consisted of an injection of 1 ml of absolute alcohol.

RESULTS

Overall efficacy rate of alcohol SPN was 67.2 %, with mean pain relief duration of 10.3 months. Procedure was graded either not painful or tolerable by patients in 64.2 %. Analysis showed a higher efficacy rate in the groups CH (76.5 %) and PFIP (85.7 %) compared to the group Other (40 %). No difference was found between groups regarding the recurrence rate.

CONCLUSION

Alcohol SPN under CT guidance appears as a safe and effective treatment of refractory facial pain, especially in cases of cluster headache and persistent idiopathic facial pain.

Pearls and pitfalls: neurostimulation in headache

CONTEXT

A variety of neuromodulatory approaches available today has broadened our therapeutic options significantly especially in drug refractory patients with chronic cluster headache and chronic migraine.

OVERVIEW

It is a dynamic field with a current trend to non-invasive transcutaneous stimulation approaches. However, sound studies providing evidence for the widespread use of these novel approaches are sparse. For invasive approaches, occipital nerve stimulation is now widely considered the treatment of first choice in chronic trigeminal autonomic cephalgias and - with limitations - chronic migraine. Although equally effective, deep brain stimulation is considered second-line treatment in cluster headache because of its potentially life-threatening side effects. Most recently, stimulation of the sphenopalatine ganglion has also been shown to effectively abort acute cluster headache attacks. Interesting other upcoming approaches include transcutaneous supraorbital nerve stimulation and transcutaneous vagal nerve stimulation.

CONCLUSION

Pearls and pitfalls of common invasive and non-invasive neuromodulatory approaches and open questions are summarised in this review along with recommendations for future studies.

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

The medical treatment of patients with chronic primary headache syndromes (chronic migraine, chronic tension-type headache, chronic cluster headache, hemicrania continua) is challenging as serious side effects frequently complicate the course of medical treatment and some patients may be even medically intractable. When a definitive lack of responsiveness to conservative treatments is ascertained and medication overuse headache is excluded, neuromodulation options can be considered in selected cases. Here, the various invasive and non-invasive approaches, such as hypothalamic deep brain stimulation, occipital nerve stimulation, stimulation of sphenopalatine ganglion, cervical spinal cord stimulation, vagus nerve stimulation, transcranial direct current stimulation, repetitive transcranial magnetic stimulation, and transcutaneous electrical nerve stimulation are extensively published although proper RCT-based evidence is limited. The European Headache Federation herewith provides a consensus statement on the clinical use of neuromodulation in headache, based on theoretical background, clinical data, and side effect of each method. This international consensus further gives recommendations for future studies on these new approaches. In spite of a growing field of stimulation devices in headaches treatment, further controlled studies to validate, strengthen and disseminate the use of neurostimulation are clearly warranted. Consequently, until these data are available any neurostimulation device should only be used in patients with medically intractable syndromes from tertiary headache centers either as part of a valid study or have shown to be effective in such controlled studies with an acceptable side effect profile.