Chronic stimulation of the posterior hypothalamic region for cluster headache: technique and 1-year results in four patients

Deep brain stimulation of the hypothalamic region: a systematic review

BACKGROUND

Deep brain stimulation (DBS) has been successfully used for the treatment of circuitopathies including movement, anxiety, and behavioral disorders. The hypothalamus is a crucial integration center for many peripheral and central pathways relating to cardiovascular, metabolic, and behavioral functions and constitutes a potential target for neuromodulation in treatment-refractory conditions. To conduct a systematic review, investigating hypothalamic targets in DBS, their indications, and the primary clinical findings.

METHODS

PubMed, Scopus, and Web of Science databases were searched in accordance with the PRISMA guideline to identify papers published in English studying DBS of the hypothalamus in humans.

RESULTS

After screening 3,148 papers, 34 studies consisting of 412 patients published over two decades were included in the final review. Hypothalamic DBS was indicated in refractory headaches (n = 238, 57.8%), aggressive behavior (n = 100, 24.3%), mild Alzheimer's disease (n = 58, 14.1%), trigeminal neuralgia in multiple sclerosis (n = 5, 1.2%), Prader-Willi syndrome (n = 4, 0.97%), and atypical facial pain (n = 3, 0.73%). The posterior hypothalamus was the most common DBS target site across 30 studies (88.2%). 262 (63.6%) participants were males, and 110 (26.7%) were females. 303 (73.5%) patients were adults whereas 33 (8.0%) were pediatrics. The lowest mean age of participants was 15.25 ± 4.6 years for chronic refractory aggressiveness, and the highest was 68.5 ± 7.9 years in Alzheimer's disease patients. The mean duration of the disease ranged from 2.2 ± 1.7 (mild Alzheimer's disease) to 19.8 ± 10.1 years (refractory headaches). 213 (51.7%) patients across 29 studies (85.3%) reported symptom improvements which ranged from 23.1% to 100%. 25 (73.5%) studies reported complications, most of which were associated with higher voltage stimulations.

CONCLUSIONS

DBS of the hypothalamus is feasible in selected patients with various refractory conditions ranging from headaches to aggression in both pediatric and adult populations. Future large-scale studies with long-term follow-up are required to validate the safety and efficacy data and extend these findings.

Neurosurgery for mental conditions and pain: An historical perspective on the limits of biological determinism

Neurosurgical operations treat involuntary movement disorders (MvDs), spasticity, cranial neuralgias, cancer pain, and other selected disorders, and implantable neurostimulation or drug delivery devices relieve MvDs, epilepsy, cancer pain, and spasticity. In contrast, studies of surgery or device implantations to treat chronic noncancer pain or mental conditions have not shown consistent evidence of efficacy and safety in formal, randomized, controlled trials. The success of particular operations in a finite set of disorders remains at odds with disconfirming results in others. Despite expectations that surgery or device implants would benefit particular patients, the normalization of unproven procedures could jeopardize the perceived legitimacy of functional neurosurgery in general. An unacknowledged challenge in functional neurosurgery is the limitation of biological determinism, wherein network activity is presumed to exclusively or predominantly mediate nociception, affect, and behavior. That notion regards certain pain states and mental conditions as disorders or dysregulation of networks, which, by implication, make them amenable to surgery. Moreover, implantable devices can now detect and analyze neural activity for observation outside the body, described as the extrinsic or micro perspective. This fosters a belief that automated analyses of physiological and imaging data can unburden the treatment of selected mental conditions and pain states from psychological subjectivity and complexity and the inherent sematic ambiguity of self-reporting. That idea is appealing; however, it discounts all other influences. Attempts to sway public opinion and regulators to approve deep brain stimulation for unproven indications could, if successful, harm the public interest, making demands for regulatory approval beside the point.

Potential hypothalamic mechanisms in trigeminal neuropathic pain: a comparative analysis with migraine and cluster headache

Trigeminal neuropathic pain (TNP), migraine, and cluster headache (CH) profoundly impact the quality of life and present significant clinical challenges due to their complex neurobiological underpinnings. This review delves into the pivotal role of the hypothalamus in the pathophysiology of these facial pain syndromes, highlighting its distinctive functions and potential as a primary target for research, diagnosis, and therapy. While the involvement of the hypothalamus in migraine and CH has been increasingly supported by imaging and clinical studies, the precise mechanisms of its role remain under active investigation. The role of the hypothalamus in TNP, in contrast, is less explored and represents a critical gap in our understanding. The hypothalamus's involvement varies significantly across these conditions, orchestrating a unique interplay of neural circuits and neurotransmitter systems that underlie the distinct characteristics of each pain type. We have explored advanced neuromodulation techniques, such as deep brain stimulation (DBS) and optogenetics, which show promise in targeting hypothalamic dysfunction to alleviate pain symptoms. Furthermore, we discuss the neuroplastic changes within the hypothalamus that contribute to the chronicity of these pains and the implications of these findings for developing targeted therapies. By offering a comprehensive examination of the hypothalamus's roles, this paper aims to bridge existing knowledge gaps and propel forward the understanding and management of facial neuralgias, underscoring the hypothalamus's critical position in future neurological research.

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.

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.

The neurobiology of cluster headache

Cluster headache is a primary headache form occurring in paroxysmal excruciatingly severe unilateral head pain attacks usually grouped in periods lasting 1-2months, the cluster periods. A genetic component is suggested by the familial occurrence of the disease but a genetic linkage is yet to be identified. Contemporary activation of trigeminal and cranial parasympathetic systems-the so-called trigemino-parasympathetic reflex-during the headache attacks seem to cause the pain and accompanying oculo-facial autonomic phenomena respectively. At peripheral level, the increased calcitonin gene related peptide (CGRP) plasma levels suggests trigeminal system activation during cluster headache attacks. The temporal pattern of the disease both in terms of circadian rhythmicity and seasonal recurrence has suggested involvement of the hypothalamic biological clock in the pathophysiology of cluster headache. The posterior hypothalamus was investigate as the cluster generator leading to activation of the trigemino-parasympathetic reflex, but the accumulated experience after 20 years of hypothalamic electrical stimulation to treat the condition indicate that this brain region rather acts as pain modulator. Efficacy of monoclonal antibodies to treat episodic cluster headache points to a key role of CGRP in the pathophysiology of the condition.

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.

Electrophysiology and Structural Connectivity of the Posterior Hypothalamic Region: Much to Learn From a Rare Indication of Deep Brain Stimulation

Cluster headache (CH) is among the most common and debilitating autonomic cephalalgias. We characterize clinical outcomes of deep brain stimulation (DBS) to the posterior hypothalamic region through a novel analysis of the electrophysiological topography and tractography-based structural connectivity. The left posterior hypothalamus was targeted ipsilateral to the refractory CH symptoms. Intraoperatively, field potentials were captured in 1 mm depth increments. Whole-brain probabilistic tractography was conducted to assess the structural connectivity of the estimated volume of activated tissue (VAT) associated with therapeutic response. Stimulation of the posterior hypothalamic region led to the resolution of CH symptoms, and this benefit has persisted for 1.5-years post-surgically. Active contacts were within the posterior hypothalamus and dorsoposterior border of the ventral anterior thalamus (VAp). Delta- (3 Hz) and alpha-band (8 Hz) powers increased and peaked with proximity to the posterior hypothalamus. In the posterior hypothalamus, the delta-band phase was coupled to beta-band amplitude, the latter of which has been shown to increase during CH attacks. Finally, we identified that the VAT encompassing these regions had a high proportion of streamlines of pain processing regions, including the insula, anterior cingulate gyrus, inferior parietal lobe, precentral gyrus, and the brainstem. Our unique case study of posterior hypothalamic region DBS supports durable efficacy and provides a platform using electrophysiological topography and structural connectivity, to improve mechanistic understanding of CH and this promising therapy.

Deep brain stimulation modulates hypothalamic-brainstem fibers in cluster headache: case report

Hypothalamic deep brain stimulation (DBS) has been used for more than a decade to treat cluster headache (CH) but its mechanisms remain poorly understood. The authors have successfully treated a patient with CH using hypothalamic DBS and found that the contact used for chronic stimulation was located in a white matter region posterior to the mammillary bodies. Fiber tracts crossing that region were the medial forebrain bundle and those interconnecting the hypothalamus and brainstem, including the dorsal longitudinal fasciculus. Because the stimulation of axons is an important mechanism of DBS, some of its clinical effects in CH may be related to the stimulation of fibers interconnecting the hypothalamus and brainstem.

Burst Occipital Nerve Stimulation for Chronic Migraine and Chronic Cluster Headache

BACKGROUND

Occipital nerve stimulation (ONS) is widely used for headache syndromes including chronic migraine (CM) and chronic cluster headache (CCH). The paraesthesia associated with tonic stimulation can be bothersome and can limit therapy. It is now clear in spinal cord stimulation that paraesthesia-free waveforms can produce effective analgesia, but this has not been reported in ONS for CM or CCH.

MATERIALS AND METHODS

Seventeen patients (12 CM and 5 CCH) were treated with bilateral burst pattern ONS, including 4 who had previously had tonic ONS. Results were assessed in terms of the frequency of headaches (number of headache days per month for CM, and number of attacks per day for CCH) and their intensity on the numeric pain rating scale.

RESULTS

Burst ONS produced a statistically significant mean reduction of 10.2 headache days per month in CM. In CCH, there were significant mean reductions in headache frequency (92%) and intensity (42%).

CONCLUSION

Paraesthesia is not necessary for good quality analgesia in ONS. Larger studies will be required to determine whether the efficacies of the two stimulation modes differ. Burst ONS is imperceptible and therefore potentially amenable to robustly blinded clinical trials.

Targeted Acid-Sensing Ion Channel Therapies for Migraine

Acid-sensing ion channels (ASICs) are a family of ion channels, consisting of four members; ASIC1 to 4. These channels are sensitive to changes in pH and are expressed throughout the central and peripheral nervous systems-including brain, spinal cord, and sensory ganglia. They have been implicated in a number of neurological conditions such as stroke and cerebral ischemia, traumatic brain injury, and epilepsy, and more recently in migraine. Their expression within areas of interest in the brain in migraine, such as the hypothalamus and PAG, their demonstrated involvement in preclinical models of meningeal afferent signaling, and their role in cortical spreading depression (the electrophysiological correlate of migraine aura), has enhanced research interest into these channels as potential therapeutic targets in migraine. Migraine is a disorder with a paucity of both acute and preventive therapies available, in which at best 50% of patients respond to available medications, and these medications often have intolerable side effects. There is therefore a great need for therapeutic development for this disabling condition. This review will summarize the understanding of the structure and CNS expression of ASICs, the mechanisms for their potential role in nociception, recent work in migraine, and areas for future research and drug development.

The efficiency analysis of thrombolytic rt-PA combined with intravascular interventional therapy in patients with acute basilar artery occlusion

In order to further optimize the treatment strategy for the patients with acute basilar artery occlusion, we were dedicated to study the therapeutic effects and influential factors in the process of treated basilar artery occlusion with thrombolytic combined vascular interventional therapy. 75 patients with acute basilar artery occlusion treated with arterial thrombolytic therapy were analyzed retrospectively. In accordance with the discharge records of patients, their short-term curative effect with 24-hour treatment and 14-days treatment were evaluated. Our data showed that the survival condition of the patients with acute acute basilar artery occlusion were visibly improved by combination thrombolytic and interventional therapy. Moreover, their BI scores were remarkably improved, while NIHSS and mRS scores were evidently reduced. These data proved that our treatment strategy was able to improve the survival condition of patients with acute basilar artery occlusion. Furthermore, our data showed that coagulation related factors remarkably improved in the patients, when they treated by combination thrombolytic therapy with interventional therapy. In addition, our results suggested that the patients' bilateral Babinski(+), revascularization and coma symptom were closely related to their prognosis after treated the patients with combination thrombolytic and vascular interventional therapy, and the difference was statistically significant (p<0.05, p<0.05, p<0.05). Besides, our data also displayed that the with stent assisted angioplasty was significantly superior to the patients with balloon angioplasty, and the difference was statistically significant (p<0.05). Anyhow, combination thrombolytic with interventional therapy can effectively promote the prognosis of the patients with acute basilar artery occlusion. The coma symptom, bilateral Babinski(+), and revascularization in the patients with acute basilar artery occlusion have an appreciable impact on the patients' prognosis.

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.

Endoventricular Deep Brain Stimulation of the Third Ventricle

BACKGROUND:

The third ventricle (3rd V) is surrounded by centers related to satiety, homeostasis, hormones, sleep, memory, and pain. Stimulation of the wall of the 3rd V could be useful to treat disorders related to dysfunction of the hypothalamus.

OBJECTIVE:

To assess safety and efficacy of endoventricular electrical stimulation of the hypothalamus using a floating deep brain stimulation (DBS) lead laid on the floor of the 3rd V to treat refractory cluster headaches (CH).

METHODS:

Seven patients, aged 24 to 60 years, experiencing chronic CH (mean chronic duration 5.8 ± 2.5 years) were enrolled in this pilot, prospective, open study assessing the safety and potential efficacy of chronic DBS of the 3rd V. Number of attacks was collected during baseline and was compared with those occurring at 3, 6, and 12 months postoperation. Any side effects that occurred during or after surgery were reported. Effect on mood was assessed using the Hospital Anxiety and Depression scale during baseline and at 6 and 12 months postoperation.

RESULTS:

Insertion of the lead into the posterior 3rd V and chronic stimulation was feasible and safe in all patients. The voltage ranged from 0.9 to 2.3 volts. The most common side effect was transient trembling vision during stimulation. At 12 months, 3 of 7 patients were pain free, 2 had 90% improvement, 1 of 7 had 75% improvement, and 1 of 7 was not significantly improved.

CONCLUSION:

This proof of concept demonstrates the feasibility, safety, and potential efficacy of 3rd V DBS using an endoventricular road that could be applied to treat various diseases involving hypothalamic areas.

Indoleamine Hallucinogens in Cluster Headache: Results of the Clusterbusters Medication Use Survey

Cluster headache is one of the most debilitating pain syndromes. A significant number of patients are refractory to conventional therapies. The Clusterbusters.org medication use survey sought to characterize the effects of both conventional and alternative medications used in cluster headache. Participants were recruited from cluster headache websites and headache clinics. The final analysis included responses from 496 participants. The survey was modeled after previously published surveys and was available online. Most responses were chosen from a list, though others were free-texted. Conventional abortive and preventative medications were identified and their efficacies agreed with those previously published. The indoleamine hallucinogens, psilocybin, lysergic acid diethylamide, and lysergic acid amide, were comparable to or more efficacious than most conventional medications. These agents were also perceived to shorten/abort a cluster period and bring chronic cluster headache into remission more so than conventional medications. Furthermore, infrequent and non-hallucinogenic doses were reported to be efficacious. Findings provide additional evidence that several indoleamine hallucinogens are rated as effective in treating cluster headache. These data reinforce the need for further investigation of the effects of these and related compounds in cluster headache under experimentally controlled settings.

Neurostimulation for Treatment of Migraine and Cluster Headache

OBJECTIVE

The objective of this narrative review is to summarize the current state of neurostimulation therapies for the treatment of migraine and/or cluster.

METHODS

For this narrative review, publications were identified by searching PubMed using the search terms "migraine" or "cluster" combined with "vagal nerve stimulation," "transcranial magnetic stimulation," "supraorbital nerve stimulation," "sphenopalatine ganglion stimulation," "occipital nerve stimulation," "deep brain stimulation," "neurostimulation," or "neuromodulation." Publications were chosen based on the quality of data that were provided and their relevance to the chosen topics of interest for this review. Reference lists of chosen articles and the authors' own files were used to identify additional publications. Current clinical trials were identified by searching clinicaltrials.org.

RESULTS AND CONCLUSIONS

Neurostimulation of the vagal nerve, supraorbital nerve, occipital nerve and sphenopalatine ganglion, transcranial magnetic stimulation (TMS), and deep brain stimulation have been investigated for the treatment of migraine and/or cluster. Whereas invasive methods of neurostimulation would be reserved for patients with very severe and treatment refractory migraine or cluster, noninvasive methods of stimulation might serve as useful adjuncts to more conventional therapies. Currently, transcutaneous supraorbital nerve stimulation is FDA approved and commercially available for migraine prevention and TMS is FDA approved for the treatment of migraine with aura. The potential utility of each type of neurostimulation has yet to be completely defined.

Deep brain stimulation for chronic pain: intracranial targets, clinical outcomes, and trial design considerations

For over half a century, neurosurgeons have attempted to treat pain from a diversity of causes using acute and chronic intracranial stimulation. Targets of stimulation have included the sensory thalamus, periventricular and periaqueductal gray, the septum, the internal capsule, the motor cortex, posterior hypothalamus, and more recently, the anterior cingulate cortex. The current work focuses on presenting and evaluating the evidence for the efficacy of these targets in a historical context while also highlighting the major challenges to having a double-blind placebo-controlled clinical trial. Considerations for pain research in general and use of intracranial targets specifically are included.

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.

Supraspinal stimulation for treatment of refractory pain

Refractory pain syndromes often have far reaching effects and are quite a challenge for primary care providers and specialists alike to treat. With the help of site-specific neuromodulation and appropriate patient selection these difficult to treat pain syndromes may be managed. In this article, we focus on supraspinal stimulation (SSS) for treatment of intractable pain and discuss off-label uses of deep brain stimulation (DBS) and motor cortex stimulation (MCS) in context to emerging indications in neuromodulation. Consideration for neuromodulatory treatment begins with rigorous patient selection based on exhaustive conservative management, elimination of secondary gains, and a proper psychology evaluation. Trial stimulation prior to DBS is nearly always performed while trial stimulation prior to MCS surgery is symptom dependent. Overall, a review of the literature demonstrates that DBS should be considered for refractory conditions including nociceptive/neuropathic pain, phantom limb pain, and chronic cluster headache (CCH). MCS should be considered primarily for trigeminal neuropathic pain (TNP) and central pain. DBS outcome studies for post-stroke pain as well as MCS studies for complex regional pain syndrome (CRPS) show more modest results and are also discussed in detail.

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.

Common cerebral networks associated with distinct deep brain stimulation targets for cluster headache

BACKGROUND

Several centers have reported efficacious cluster headache suppression with deep brain stimulation (DBS) of the hypothalamic region using a variety of targets. While the connectivity of some of these targets has individually been studied, commonalities across these targets, especially with respect to network-level connectivity, have not previously been explored.

METHODS

We examined the anatomic connectivity of the four distinct DBS targets reported in the literature using probabilistic diffusion tensor tractography in normal subjects.

RESULTS

Despite being described as hypothalamic, the DBS targets localized in the midbrain tegmentum posterior to the hypothalamus. Common tracts across DBS targets and subjects included projections to the ipsilateral hypothalamus, reticular formation, and cerebellum.

DISCUSSION

Although DBS target coordinates are not located within the hypothalamus, a strong connection between DBS targets and the hypothalamus likely exists. Moreover, a common projection to the medial ipsilateral cerebellum was identified. Understanding the common connectivity of DBS-targeted regions may elucidate anatomic pathways that are involved in modulating cluster headache attacks and facilitate more precise patient-specific targeting of DBS.

The effect of posterior hypothalamus region deep brain stimulation on sleep

BACKGROUND

Early observations by von Economo showed that the posterior part of the hypothalamus (PH) plays a prominent role in sleep-wake regulation. The PH is a candidate area involved in cluster headaches and other trigeminal autonomic cephalalgias (TACs) and is targeted for deep brain stimulation (DBS).

CASE REPORTS

Sleep studies in two men, 69- and 39-years-old, with pre-existing sleep disorders, before and after PH-DBS for pharamacoresistant cluster headache and SUNCT syndrome showed that PH-DBS led to a dramatic alteration of the patients' sleep patterns. This coincided with an improvement of the predominantly diurnal TACs, suggesting a PH-DBS-induced change in sleep patterns. Hypnograms after DBS demonstrated disrupted sleep and a prolonged period of wakefulness after midnight in both patients, which was reproduced the second night.

CONCLUSIONS

PH-DBS, a promising treatment for severe refractory TACs, affects sleep quality and pre-existing sleep disorders. This needs to be considered when treating patients with PH-DBS.

Neurostimulators for the treatment of primary headaches

Neurostimulation techniques have increased our therapeutic armamentarium, providing additional options for the treatment of patients with drug-resistant headache. Occipital nerve stimulation can be considered in drug-resistant chronic cluster headache and, with more caution, in drug-resistant chronic migraine. Approximately 12 years after its introduction, hypothalamic stimulation is a valid option for drug-resistant chronic cluster headache to be considered when occipital nerve stimulation fails. Several other peripheral stimulation approaches (in addition to occipital nerve stimulation) have been introduced in recent years; however, for the most part, appropriate studies supporting their efficacy are lacking. Transcranial magnetic stimulation, transcutaneous supraorbital nerve stimulation, sphenopalatine ganglion stimulation and vagal nerve stimulation have all been tried, but results are not wholly convincing, and more extensive evaluations are required.

Neurostimulation in cluster headache: A review of current progress

Purpose of review

Neurostimulation has emerged as a viable treatment for intractable chronic cluster headache. Several therapeutic strategies are being investigated including stimulation of the hypothalamus, occipital nerves and sphenopalatine ganglion. The aim of this review is to provide an overview of the rationale, methods and progress for each of these.

Latest findings

Results from a randomized, controlled trial investigating sphenopalatine ganglion stimulation have just been published. Reportedly the surgery is relatively simple and it is apparently the only therapy that provides relief acutely.

Summary

The rationale behind these therapies is based on growing evidence from clinical, hormonal and neuroimaging studies. The overall results are encouraging, but unfortunately not all patients have benefited. All the mentioned therapies require weeks to months of stimulation for a prophylactic effect to occur, suggesting brain plasticity as a possible mechanism, and only stimulation of the sphenopalatine ganglion has demonstrated an acute, abortive effect. Predictors of effect for all modes of neurostimulation still need to be identified and in the future, the least invasive and most effective strategy must be preferred as first-line therapy for intractable chronic cluster headache.

Neuromodulation for cephalgias

Headaches (cephalgias) are a common reason for patients to seek medical care. There are groups of patients with recurrent headache and craniofacial pain presenting with malignant course of their disease that becomes refractory to pharmacotherapy and other medical management options. Neuromodulation can be a viable treatment modality for at least some of these patients. We review the available evidence related to the use of neuromodulation modalities for the treatment of medically refractory craniofacial pain of different nosology based on the International Classification of Headache Disorders, 2(nd) edition (ICHD-II) classification. This article also reviews the scientific rationale of neuromodulation application in management of cephalgias.

Advances and challenges in neurostimulation for headaches

Many people who suffer from primary headache (ie, headache without an identifiable cause) are resistant or intolerant to available drugs. During the past decade, central and peripheral neurostimulation procedures have been investigated in such individuals--up to now, about 1200 worldwide. Techniques used range from invasive methods such as deep brain stimulation of the posterior hypothalamus, to minimally invasive percutaneous electrode implantation used in occipital nerve stimulation, or non-invasive methods such as transcranial magnetic stimulation. Although some of these procedures have been studied extensively, sham-controlled trials are sparse and the precise mode of action of such stimulation remains largely unknown. Nonetheless, occipital nerve stimulation and deep brain stimulation of the posterior hypothalamus seem to be effective in people with chronic cluster headache, and occipital nerve stimulation is promising in chronic migraine. Trial data for other techniques are scarce, but external and minimally invasive approaches should be privileged in future studies.

Surgical treatment of primary headaches

Neuromodulation for the treatment of drug-refractory cranial neuralgias constitutes an exciting field of research for physicians; in the last decade, several methodologies have been described which could help many patients to exit such desperate conditions; although the exact mechanisms of action of these techniques are still matter of debate, several experimental and neuroradiological modalities can help us to get near the concept of understanding them. In this paper, the authors summarize the most recent surgical procedures used to treat severe and pharmaco-resistant cranial painful conditions, along with brief descriptions of the results obtained in the several published so far.

Wireless fast-scan cyclic voltammetry measurement of histamine using WINCS--a proof-of-principle study

Histamine is among the most poorly understood biogenic amines, yet the histaminergic system spreads throughout the brain and has been implicated in functions as diverse as homeostasis and synaptic plasticity. Not surprisingly then, it has been linked to a number of conditions including minimally conscious state, persistent vegetative state, epilepsy, addiction, cluster headache, essential tremor, and Parkinson's disease. We have previously reported that the Wireless Instantaneous Neurotransmitter Concentration Sensing (WINCS) system can monitor dopamine, serotonin, and adenosine using fast-scan cyclic voltammetry (FSCV). Here, we demonstrate the expanded capability of the WINCS system to measure histamine. The optimal FSCV waveform was determined to be a triangle wave scanned between -0.4 and +1.4 V at a rate of 400 V s(-1) applied at 10 Hz. Using this optimized FSCV parameter, we found histamine release was induced by high frequency electrical stimulation at the tuberomammillary nucleus in rat brain slices. Our results suggest that the WINCS system can provide reliable, high fidelity measurements of histamine, consistently showing oxidative currents at +1.3 V, a finding that may have important clinical implications.

Neuromodulation of the posterolateral hypothalamus for the treatment of chronic refractory cluster headache: Experience in five patients with a modified anatomical target

INTRODUCTION

Deep brain stimulation (DBS) of the posterior hypothalamus has been found to be effective in the treatment of refractory chronic cluster headache (CCH).

METHODS

We report the long-term outcomes of five patients with refractory CCH on whom stimulation of a modified target of approximately 3 mm in radius, which included the posterolateral hypothalamus, the fasciculus mammillotegmentalis, the fasciculus mammillothalamicus and the fasciculus medialis telencephali, was performed. The stereotaxic coordinates were 4 mm from the third ventricle wall, 2 mm from behind the mid-intercommissural point and 5 mm from under the intercommissural line.

RESULTS

All patients became pain-free for 1-2 weeks after the procedure, but then needed an average of 54 days to optimize stimulation parameters. After a mean follow-up of 33 months, two remain pain-free, two have an excellent response (>90% decrease in attack frequency) and in one the attacks have been reduced by half. There were no serious adverse events. Permanent myosis and euphoria/well-being feeling were seen in three patients. Other adverse events, such as diplopia, dizziness, global headache of cervical dystonia, were seen transiently related to an increase in stimulation parameters. Attacks reappeared transiently in two patients as a result of cable rupture and when the stimulator was disconnected.

CONCLUSIONS

Our results supports the efficacy of DBS in very refractory CCH with a slightly modified hypothalamic target conceived to avoid the lateral ventricle wall so as to extend the stimulated brain area and to decrease the morbidity of potential haemorrhagic complications.

Hypothalamic deep brain stimulation in the treatment of chronic cluster headache

Cluster headache (CH) is a short-lasting unilateral headache associated with ipsilateral craniofacial autonomic manifestations. A positron emission tomography (PET) study has shown that the posterior hypothalamus is activated during CH attacks, suggesting that hypothalamic hyperactivity plays a key role in CH pathophysiology. On this basis, stimulation of the ipsilateral posterior hypothalamus was hypothesized to counteract such hyperactivity to prevent intractable CH. Ten years after its introduction, hypothalamic stimulation has been proved to successfully prevent attacks in more than 60% of 58 hypothalamic implanted drug-resistant chronic CH patients. The implantation procedure has generally been proved to be safe, although it carries a small risk of brain haemorrhage. Long-term stimulation is safe, and nonsymptomatic impairment of orthostatic adaptation is the only noteworthy change. Microrecording studies will make it possible to better identify the target site. Neuroimaging investigations have shown that hypothalamic stimulation activates ipsilateral trigeminal complex, but with no immediate perceived sensation within the trigeminal distribution. Other studies on the pain threshold in chronically stimulated patients showed increased threshold for cold pain in the distribution of the first trigeminal branch ipsilateral to stimulation. These studies suggest that activation of the hypothalamus and of the trigeminal system are both necessary, but not sufficient to generate CH attacks. In addition to the hypothalamus, other unknown brain areas are likely to play a role in the pathophysiology of this illness. Hypothalamus implantation is associated with a small risk of intracerebral haemorrhage and must be performed by an expert neurosurgical team, in selected patients.

Deep brain stimulation: current and future clinical applications

Deep brain stimulation (DBS) has developed during the past 20 years as a remarkable treatment option for several different disorders. Advances in technology and surgical techniques have essentially replaced ablative procedures for most of these conditions. Stimulation of the ventralis intermedius nucleus of the thalamus has clearly been shown to markedly improve tremor control in patients with essential tremor and tremor related to Parkinson disease. Symptoms of bradykinesia, tremor, gait disturbance, and rigidity can be significantly improved in patients with Parkinson disease. Because of these improvements, a decrease in medication can be instrumental in reducing the disabling features of dyskinesias in such patients. Primary dystonia has been shown to respond well to DBS of the globus pallidus internus. The success of these procedures has led to application of these techniques to multiple other debilitating conditions such as neuropsychiatric disorders, intractable pain, epilepsy, camptocormia, headache, restless legs syndrome, and Alzheimer disease. The literature analysis was performed using a MEDLINE search from 1980 through 2010 with the term deep brain stimulation, and several double-blind and larger case series were chosen for inclusion in this review. The exact mechanism of DBS is not fully understood. This review summarizes many of the current and potential future clinical applications of this technology.

[Therapeutic neuromodulation in primary headaches]

Neuromodulatory techniques have developed rapidly in the therapeutic management of refractory headaches. Invasive procedures comprise peripheral nerve stimulation (particularly occipital nerve stimulation), vagus nerve stimulation, cervical spinal cord stimulation and hypothalamic deep brain stimulation. Transcutaneous electrical nerve stimulation, repetitive transcranial magnetic stimulation and transcranial direct current stimulation are noninvasive variants. Based on current neuroimaging, neurophysiological and clinical studies occipital nerve stimulation and hypothalamic deep brain stimulation are recommended for patients with chronic cluster headache. Less convincing evidence can be found for their use in other refractory headaches such as chronic migraine. No clear recommendation can be given for the other neuromodulatory techniques. The emerging concept of intermittent stimulation of the sphenopalatine ganglion is nonetheless promising. Robust randomized and sham-controlled multicenter studies are needed before these therapeutic approaches are widely implemented. Due to the experimental nature all patients should be treated in clinical studies. It is essential to confirm the correct headache diagnosis and the refractory nature before an invasive approach is considered. Patients should generally be referred to specialized interdisciplinary outpatient departments which closely collaborate with neurosurgeons who are experienced in the implantation of neuromodulatory devices. It is crucial to ensure a competent postoperative follow-up with optimization of stimulation parameters and adjustment of medication.

Deep brain stimulation of the posterior hypothalamic area in intractable short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT)

Background: SUNCT (short-lasting unilateral neuralgiform headache with conjunctival injection and tearing) is a rare syndrome characterized by the sudden onset of excruciating unilateral periorbital pain that is accompanied by conjunctival injection and lacrimation or further autonomic signs. Similar to patients with chronic cluster headache, Leone and Lyons showed a beneficial effect of deep brain stimulation of the posterior hypothalamic region in two patients with a chronic SUNCT.

Case: Here, we present the case of a man with a chronic SUNCT responding to deep brain stimulation of the posterior hypothalamic area.

Conclusion: This case supports the idea of a central origin of SUNCT and shows that deep brain stimulation of the hypothalamic region can be effective in the treatment of the chronic form of this rare disorder.