Deep brain stimulation to relieve drug-resistant SUNCT

Short-lasting unilateral neuralgiform headache attacks (SUNCT/SUNA): a narrative review of interventional therapies

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache with autonomic symptoms (SUNA) are disabling primary headache disorders. The advent of advanced imaging technologies and surgical techniques has translated to a growing arsenal of interventional therapies capable of treating headache disorders. This literature review sheds light on the current evidence available for interventional therapies in medically intractable SUNCT/SUNA. PubMed and EMBASE were searched for publications between 1978 and 2022. Inclusion criteria were SUNCT/SUNA studies reporting outcomes following occipital nerve stimulation (ONS), pulsed radiofrequency (PRF) of sphenopalatine ganglion (SPG), stereotactic radiosurgery (SRS), deep brain stimulation (DBS) or microvascular decompression (MVD) of the trigeminal nerve. A greater than 50% reduction in severity or a greater than 50% reduction in the number of attacks was defined as a successful response. The rate of successful responses for the various treatment modalities were as follows: ONS 33/41 (80.5%), PRF of SPG 5/9 (55.6%), DBS of the ventral tegmental area 14/16 (86.7%), SRS to the SPG and/or trigeminal nerve 7/9 (77.8%) and MVD 56/73 (76.7%). Mean follow-up time in months was 42.5 (ONS), 24.8 (PRF), 25.3 (DBS), 20.8 (SRS) and 42.4 (MVD). A significant proportion of SUNCT/SUNA patients remain refractory to medical therapy (45%-55%). This review discusses existing literature on interventional approaches, including neuromodulation, radiofrequency ablation, gamma knife radiosurgery and MVD. The outcomes are promising, yet limited data exist, underscoring the need for further research to develop a robust surgical management algorithm.

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.

Perioperative complications of deep brain stimulation among patients with advanced age: a single-institution retrospective analysis

OBJECTIVE

Deep brain stimulation (DBS) is an elective procedure that can dramatically enhance quality of life. Because DBS is not considered lifesaving, it is important that providers produce consistently good outcomes, and one factor they usually consider is patient age. While older age may be a relative contraindication for some elective surgeries, the progressive nature of movement disorders treated with DBS may suggest that older patients stand to benefit substantially from surgery. To better understand the risks of treating patients of advanced age with DBS, this study compares perioperative complication rates in patients ≥ 75 to those < 75 years old.

METHODS

Patients undergoing DBS surgery for various indications by a single surgeon (May 2013-July 2019) were stratified into elderly (age ≥ 75 years) and younger (age < 75 years) cohorts. The risks of common perioperative complications and various outcome measures were compared between the two age groups using risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS

A total of 861 patients were available for analysis: 179 (21%) were ≥ 75 years old and 682 (79%) were < 75 years old (p < 0.001). Patients ≥ 75 years old, compared with those < 75 years old, did not have significantly different RRs (95% CIs) of seizure (RR 0.4, 95% CI 0.1-3.3), cerebrovascular accident (RR 1.9, 95% CI 0.4-10.3), readmission within 90 days of discharge (RR 1.22, 95% CI 0.8-1.8), explantation due to infection (RR 2.5, 95% CI 0.4-15.1), or surgical revision (for lead, RR 2.5, 95% CI 0.4-15.1; for internal pulse generator, RR 3.8, 95% CI 0.2-61.7). Although the risk of postoperative intracranial bleeding was higher in the elderly group (6.1%) than in the younger group (3.1%), this difference was not statistically significant (p = 0.06). However, patients ≥ 75 years old did have significantly increased risk of altered mental status (RR 2.5, 95% CI 1.6-4.0), experiencing more than a 1-night stay (RR 1.7, 95% CI 1.4-2.0), and urinary retention (RR 2.3, 95% CI 1.2-4.2; p = 0.009).

CONCLUSIONS

Although elderly patients had higher risks of certain outcome measures than younger patients, this study showed that elderly patients undergoing DBS for movement disorders did not have an increased risk of more serious complications, such as intracranial hemorrhage, infection, or readmission. Advanced age alone should not be considered a contraindication for DBS.

SUNCT/SUNA in Pediatric Age: A Review of Pathophysiology and Therapeutic Options

The International Classification of Headache Disorders, 3rd edition (ICHD3) defines Short-lasting Unilateral Neuralgiform Headache Attacks (SUNHA) as attacks of moderate or severe, strictly unilateral head pain lasting from seconds to minutes, occurring at least once a day and usually associated with prominent lacrimation and redness of the ipsilateral eye. Two subtypes of SUNHA are identified: Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing (SUNCT) and Short-lasting Unilateral Neuralgiform headache attacks with cranial Autonomic symptoms (SUNA). These pathologies are infrequent in children and difficult to diagnose. The authors reviewed the existing literature on SUNCT and SUNA, especially in the developmental age, which describes the pathophysiology in detail and focuses on the therapeutic options available to date. SUNHA-type headaches must be considered on the one hand, for the possibility of the onset of forms secondary to underlying pathologies even of a neoplastic nature, and on the other hand, for the negative impact they can have on an individual’s quality of life, particularly in young patients. Until now, published cases suggest that no chronic variants occur in childhood and adolescents. In light of this evidence, the authors offer a review that may serve as a source to be drawn upon in the implementation of suitable treatments in children and adolescents suffering from these headaches, focusing on therapies that are non-invasive and as risk-free as possible for pediatric patients.

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.

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.

Short-Lasting Unilateral Neuralgiform Headache With Conjunctival Injection and Tearing (SUNCT) Improves With Bilateral Ventral Tegmental Area Deep Brain Stimulation

BACKGROUND

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a severe headache disorder characterized by clustered episodes of extreme pain. Refractory to most interventions, ipsilateral unilateral ventral tegmental area (VTA) deep brain stimulation (DBS) has been previously reported to be efficacious in 14 cases.

METHODS AND RESULTS

Herein, we report the first case of an individual with medically refractory SUNCT who underwent bilateral VTA DBS. The patient experienced better improvement of his headaches with bilateral stimulation compared to unilateral stimulation. He also had a return of severe headaches within a few hours after his stimulator was switched off during sleep, with rebound worsening of his headaches over several days. The main side effects were double vision and difficulty focusing while reading, which were observed primarily with unipolar stimulation that required high voltages, high frequencies, and multiple negative contacts to control the headaches. The side effects were minimized with bipolar and interleaving stimulation with comparable control of his headaches.

CONCLUSION

Bilateral VTA DBS may be effective in alleviating medical refractory SUNCT.

Primaries non-migraine headaches treatment: a review

In the "headache world," great attention has always been paid to migraine patients, especially for the research and development of new therapies. For the other forms of primary headaches, especially those of Chapters 2 and 3 of the classification, there are however therapies that, even if not specific, can give significant results. Tension-type headache recognizes in NSAIDs the most effective drugs to treat acute attack, while prevention is based on the use of tricyclic antidepressants and muscle relaxants. For TACs, the discussion is more complex: first of all, there are two forms of primary headache that respond absolutely to indomethacin. For these, the main problem is how to manage the possible side effects arising from prolonged treatments and possibly what to use as an alternative. For cluster headaches and short-lasting unilateral neuralgiform headache attacks, we have drugs with good efficacy as regards medical therapy, such as verapamil or lamotrigine, but in recent years, neuromodulation techniques, both surgical and non-invasive, have also been affirming themselves, which represent a more possibility for forms of headache that are often very disabling and resistant to common analgesics.

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.

Primary Headaches

The primary headaches are composed of multiple entities that cause episodic and chronic head pain in the absence of an underlying pathologic process, disease, or traumatic injury. The most common of these are migraine, tension-type headache, and the trigeminal autonomic cephalalgias. This article reviews the clinical presentation, pathophysiology, and treatment of each to help in differential diagnosis. These headache types share many common signs and symptoms, thus a clear understanding of each helps prevent a delay in diagnosis and inappropriate or ineffective treatment. Many of these patients seek dental care because orofacial pain is a common presenting symptom.

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.

Microvascular decompression or neuromodulation in patients with SUNCT and trigeminal neurovascular conflict?

Objectives

To assess the effectiveness of neuromodulation and trigeminal microvascular decompression (MVD) in patients with medically-intractable short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT).

Methods

Two patients with medically refractory SUNCT underwent MVD following beneficial but incomplete response to neuromodulation (occipital nerve stimulation and deep brain stimulation). MRI confirmed neurovascular conflict with the ipsilateral trigeminal nerve in both patients.

Results

Although neuromodulation provided significant benefit, it did not deliver complete relief from pain and management required numerous postoperative visits with adjustment of medication and stimulation parameters. Conversely, MVD was successful in eliminating symptoms of SUNCT in both patients with no need for further medical treatment or neuromodulation.

Conclusion

Neuromodulation requires expensive hardware and lifelong follow-up and maintenance. These case reports highlight that microvascular decompression may be preferable to neuromodulation in the subset of SUNCT patients with ipsilateral neurovascular conflict.

Therapeutical approaches to paroxysmal hemicrania, hemicrania continua and short lasting unilateral neuralgiform headache attacks: a critical appraisal

Background

Hemicrania continua (HC), paroxysmal hemicrania (PH) and short lasting neuralgiform headache attacks (SUNCT and SUNA) are rare syndromes with a difficult therapeutic approach. The aim of this review is to summarize all articles dealing with treatments for HC, PH, SUNCT and SUNA, comparing them in terms of effectiveness and safety.

Methods

A survey was performed using the pubmed database for documents published from the 1st January 1989 onwards. All types of articles were considered, those ones dealing with symptomatic cases and non-English written ones were excluded.

Results

Indomethacin is the best treatment both for HC and PH. For the acute treatment of HC, piroxicam and celecoxib have shown good results, whilst for the prolonged treatment celecoxib, topiramate and gabapentin are good options besides indomethacin. For PH the best drug besides indomethacin is piroxicam, both for acute and prolonged treatment. For SUNCT and SUNA the most effective treatments are intravenous or subcutaneous lidocaine for the acute treatment of active phases and lamotrigine for the their prevention. Other effective therapeutic options are intravenous steroids for acute treatment and topiramate for prolonged treatment. Non-pharmacological techniques have shown good results in SUNCT and SUNA but, since they have been tried on a small number of patients, the reliability of their efficacy is poor and their safety profile mostly unknown.

Conclusions

Besides a great number of treatments tried, HC, PH, SUNCT and SUNA management remains difficult, according with their unknown pathogenesis and their rarity, which strongly limits the studies upon these conditions. Further studies are needed to better define the treatment of choice for these conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-017-0777-3) contains supplementary material, which is available to authorized users.

Long-term follow up of intractable chronic short lasting unilateral neuralgiform headache disorders treated with occipital nerve stimulation

Background Occipital nerve stimulation is a potential treatment option for medically intractable short-lasting unilateral neuralgiform headache attacks. We present long-term outcomes in 31 patients with short-lasting unilateral neuralgiform headache attacks treated with occipital nerve stimulation in an uncontrolled open-label prospective study. Methods Thirty-one patients with intractable short-lasting unilateral neuralgiform headache attacks were treated with bilateral occipital nerve stimulation from 2007 to 2015. Data on attack characteristics, quality of life, disability and adverse events were collected. Primary endpoint was change in mean daily attack frequency at final follow-up. Results At a mean follow-up of 44.9 months (range 13-89) there was a 69% improvement in attack frequency with a response rate (defined as at least a 50% improvement in daily attack frequency) of 77%. Attack severity reduced by 4.7 points on the verbal rating scale and attack duration by a mean of 64%. Improvements were seen in headache-related disability and depression. Adverse event rates were favorable, with no electrode migration or erosion reported. Conclusion Occipital nerve stimulation appears to offer a safe and efficacious treatment for refractory short-lasting unilateral neuralgiform headache attacks with significant improvements sustained in the long term. The procedure has a low adverse event rate when conducted in highly specialised units.

SUN: Short-Lasting Unilateral Neuralgiform Headache Attacks

PREMISE

Short-lasting unilateral neuralgiform headache attacks (SUN) are part of the group of primary headaches called trigeminal autonomic cephalalgias (TACs). They are characterized by unilateral attacks of pain with associated ipsilateral cranial autonomic symptoms.

PROBLEM

Recently the classification of these attacks has changed, to incorporate the different types of autonomic symptoms such as conjunctival injection and tearing (or lack thereof). Previously considered to be rare and rather refractory to treatment, there is an increasing awareness of this syndrome and the therapeutic possibilities.

DISCUSSION

This article discusses the clinical aspects of the syndrome, pathophysiology, current, and future treatments.

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.

Short-Lasting Unilateral Neuralgiform Headache Attacks with Conjunctival Injection and Tearing

SUNCT (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing) and SUNA (Short-lasting Unilateral Neuralgiform headache attacks with cranial Autonomic symptoms) are rare primary headache syndromes, classified as Trigeminal Autonomic Cephalalgias (TACs). Hypothalamic involvement in the TACs has been suggested by functional imaging data and clinically with deep brain stimulation.

Fifty-two patients (43 SUNCT, 9 SUNA) were studied to determine the clinical phenotype of these conditions and response to medications. A functional imaging study explored activation of the posterior hypothalamus in attacks of SUNCT/SUNA.

The clinical study characterised SUNCT and SUNA in terms of epidemiology, phenotype and clinical characteristics.

Indomethacin is ineffective on single-blind testing. Intravenous lidocaine was effective in all cases. Open-label trails showed the effectiveness of lamotrigine, topiramate and gabapentin.

On functional imaging there was hypothalamic activation bilaterally in 5/9 SUNCT patients, and contralaterally in two patients. Two SUNCT patients had ipsilateral negative activation. In SUNA the activation was bilaterally negative. There was no hypothalamic activation in a patient with SUNCT secondary to a brainstem lesion.

The data suggests that there should be revised classification for SUNCT and SUNA, with an increased range of attack duration and frequency, cutaneous triggering of attacks, and a lack of refractory period. The concept of ‘attack load’ is introduced. The lack of response to indomethacin and the response to intravenous lidocaine, are useful in diagnostic and therapeutic terms, respectively. Preventive treatments include lamotrigine, gabapentin and topiramate. The role of hypothalamic involvement in SUNCT and SUNA as TACs is considered.

Botulinum Toxin A for the Treatment of a Child with SUNCT Syndrome

Background. Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) syndrome is an unusual cause of headache, mainly described in older adults, and is rare in children. Pain attacks may be severe, frequent, and prolonged. The therapeutic benefits of many drugs are disappointing. Patient and Methods. A 12-year-old boy suffered severe headache and toothache for 20 days. As treatment with nonsteroidal anti-inflammatory drugs, anticonvulsants, and steroids proved ineffective, he was treated with ipsilateral multisite subcutaneous injections of botulinum toxin A 70 U around the orbit, the temporal area, and the upper gum. Results. The pain had reduced in frequency and severity by the fourth day after treatment and had completely disappeared after 7 days. There were no side effects or recurrence during a subsequent 17-month follow-up period. Conclusion. Botulinum toxin A can be used to treat the first episode of SUNCT in children over the age of 12 years.

SUNCT/SUNA: A Review

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting neuralgiform headache attacks with cranial autonomic features (SUNA) are rare headache disorders characterized by severe, short-lasting headaches. These headache disorders are often refractory to treatment and can be secondary phenomena. This article reviews the history, pathophysiology, and treatment of these disorders. Both pharmacotherapy and procedural interventions are discussed in context of historical and more recent reports.

Tic versus TAC: differentiating the neuralgias (trigeminal neuralgia) from the cephalalgias (SUNCT and SUNA)

Trigeminal neuralgia, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with autonomic symptoms (SUNA) are classified as distinct disorders in the International Classification of Headache Disorders 3 beta (ICHD-3 beta). SUNCT and SUNA are primary headache disorders included among the trigeminal autonomic cephalalgias. Trigeminal neuralgia is classified under painful cranial neuropathies and other facial pains. The classification criteria of these conditions overlap significantly which could lead to misdiagnosis. The reported overlap among these conditions has called into question whether they should be considered distinct entities or rather a continuum of the same disorder. This review explores the known overlap and how other features not included in the ICHD-3 beta criteria may better differentiate the "Tics" (trigeminal neuralgia) from the "TACs" (SUNCT and SUNA).

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.

Pathogenesis, Surgical Treatment, and Cure for SUNCT Syndrome

BACKGROUND

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) are characterized by attacks of moderate to severe stabbing pain, strictly unilateral, with periorbital or temporal distribution, associated with cranial autonomic symptoms, such as lacrimation and redness of the ipsilateral eye.

METHODS

To obtain mechanistic insights into the pathogenesis of SUNCT syndrome, more than 800 cases treated in our institution during the last 7 years were retrospectively reviewed. Two patients showed typical autonomic symptoms of SUNCT.

RESULTS

Magnetic resonance imaging suggested potential compression of the trigeminal nerve by the intracranial artery in these cases and complete remission was achieved by microvascular decompression.

CONCLUSIONS

Microvascular decompression provides an appropriate therapeutic choice if vascular compression of the trigeminal nerve is identified. From our 2 cases, we propose that, in some cases of SUNCT diagnosed previously, characteristic symptoms were induced by compression of the side surface of the first branch of the trigeminal nerve at the root exit zone by the intracranial artery.

Trigeminal autonomic cephalalgias: beyond the conventional treatments

The trigeminal autonomic cephalalgias include cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks, and hemicrania continua. While the majority responds to conventional pharmacological treatments, a small but significant proportion of patients are intractable to these treatments. In these cases, alternative choices for these patients include oral and injectable drugs, lesional or resectional surgery, and neurostimulation. The evidence base for conventional treatments is limited, and the evidence for those used beyond convention is more so. At present, the most evidence exists for nerve blocks, deep brain stimulation, occipital nerve stimulation, sphenopalatine ganglion stimulation in chronic cluster headache, and microvascular decompression of the trigeminal nerve in short-lasting unilateral neuralgiform headache attacks.

Strictly unilateral headaches: considerations of a clinician

The aim of the lecture is to draw attention to the role that clinical practice and clinical observation have had in stimulating research on the pathophysiology of cluster headache (CH) and other trigeminal autonomic cephalalgias (TACs). The symptoms of cluster headache-in particular the typical circadian periodicity of the headaches and the seasonal recurrence of cluster periods-were fundamental in shifting attention away from peripheral pathogenetic hypotheses to the idea that cluster headache could have a central origin. Initially, solid neuroendocrinological data pointed to hypothalamic involvement. For example, CH patients were shown to have alterations in biorhythms. Subsequently, modern functional neuroimaging techniques were able to demonstrate that the homolateral posterior hypothalamus is activated during TAC headaches, so implicating this region in TAC pathogenesis. It is known that the hypothalamus has a modulatory effect on nociceptive and autonomic pathways, particularly on the nociceptive trigeminovascular system. Future research should clarify whether the hypothalamus is the generator of TAC headaches, or whether it is activated in response to an alteration of the homeostatic equilibrium between limbic emotional-affective components and autonomic-nociceptive components modulated by the hypothalamus.

SUNCT, SUNA and trigeminal neuralgia: different disorders or variants of the same disorder?

PURPOSE OF REVIEW

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), short-lasting unilateral neuralgiform headache attacks with autonomic symptoms (SUNA) and trigeminal neuralgia are considered different disorders, thus grouped in separate sections of the International Classification of Headache Disorders 3 beta. However, the clinical, radiological and therapeutic overlap between SUNCT, SUNA, and trigeminal neuralgia has challenged this traditional view. This review summarizes the available clinical and pathophysiological evidence on whether SUNCT, SUNA and trigeminal neuralgia should be considered separate entities or variants of the same disorder.

RECENT FINDINGS

Data on the clinical phenotype and effective management strategies in SUNCT and SUNA syndromes have shown striking similarities with trigeminal neuralgia. Moreover, studies exploring radiological findings supported the hypothesis of common aetiological and pathophysiological basis between SUNCT/SUNA and trigeminal neuralgia. However, a limitation of most studies is that they have included small samples of patients and therefore any conclusions need to be drawn cautiously.

SUMMARY

Despite being considered distinct conditions, emerging clinical and radiological evidence supports a broader nosological concept of SUNCT, SUNA, and trigeminal neuralgia. These conditions may constitute a continuum of the same disorder, rather than separate clinical entities. Further evidence is required to shed light on this nosological issue, given its potential impact on clinical practice and further research studies in this area.

Intractable SUNCT Cured After Resection of a Pituitary Microadenoma

Background:

SUNCT is a rare primary headache disorder that is associated with activation of the posterior hypothalamus and often poorly responsive to medication. Recently, a relationship between between pituitary microadenoma and SUNCT has been suggested, and reports of both amelioration and exacerbation by dopamine-agonists have been published. These findings suggest a functional role for the hypothalamic-pituitary axis in SUNCT.

Methods:

We report the long-term 4 year follow-up of a 35 year-old patient with a 14-year history of medically and surgically intractable SUNCT who experienced immediate and complete resolution of symptoms after resection of a 6 mm pituitary microadenoma.

Results:

This patient was first seen at the age of 28 years with a 10-year history of attacks of right retro-orbital pain satisfying the IHS criteria for SUNCT. Many medical and surgical treatments were attempted without success. An MRI demonstrated a 6 mm microadenoma without compression of surrounding structures. A trial of bromocriptine caused marked exacerbation of his pain. The patient underwent a trans-sphenoidal resection of the pituitary lesion. SUNCT attacks worsened for the first 24h post-operatively, then disappeared. He has been completely headache-free, without medication, for the past 43 months with the last follow-up being January 2006.

Conclusion:

This case emphasizes the relationship between pituitary microadenomas and SUNCT, supports the role of the hypothalamic-pituitary axis in the genesis of SUNCT, and illustrates the importance of careful imaging of the pituitary region in patients with SUNCT.

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.

SUNCT and SUNA: medical and surgical treatments

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) are rare and often disabling primary headache disorders. Their management can be challenging. The abortive therapies are not generally useful as the attacks are relatively short lasting. A myriad of pharmacological preventive treatments have been tried in single case reports or small series in an open-label fashion. Lamotrigine, as an oral preventive treatment, and lidocaine, as an intravenous transitional treatment, seem to be the most effective therapies. For medically intractable chronic forms of SUNCT and SUNA, several surgical approaches have been tried. These include ablative procedures involving the trigeminal nerve or the Gasserian ganglion, microvascular decompression of the trigeminal nerve, and neurostimulation techniques. This review provides an overview of the current pharmacological and surgical options for SUNCT and SUNA syndromes.

Functional neuroimaging of primary headache disorders

Until recently, primary headache disorders, such as migraine and cluster headache were considered to be vascular in origin. However, advances in neuroimaging techniques, such as positron emission tomography, single photon emission computed tomography and functional magnetic resonance imaging have augmented the growing clinical evidence that these headaches are primarily driven from the brain. This review covers functional imaging studies in migraine, cluster headache, rarer headache syndromes and experimental head pain. Together with newer techniques, such as voxel-based morphometry and magnetic resonance spectrometry, functional imaging continues to play a role in elucidating and targeting the neural substrates in each of the primary headache syndromes.

Role of trigeminal microvascular decompression in the treatment of SUNCT and SUNA

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) are primary headache disorders. Evidence suggests that SUNCT/SUNA have similar pathophysiology to the trigeminal autonomic cephalalgias and involves the trigeminal autonomic reflex. This review provides an overview of microvascular decompression of the trigeminal nerve and other surgical therapeutic options for SUNCT/SUNA. We have undertaken a mini-meta-analysis of available case reports and case series with the aim of providing recommendations for the use of such therapies in SUNCT/SUNA. There is some evidence supporting microvascular decompression of the trigeminal nerve in selected patients who have medically refractory SUNCT/SUNA and a demonstrable ipsilateral aberrant vessel on magnetic resonance imaging (MRI). We also consider what further investigations could be undertaken to assess the role of surgical interventions in the treatment of these often debilitating conditions.

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.

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.

SUNCT/SUNA and neurovascular compression: new cases and critical literature review

BACKGROUND

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache with cranial autonomic symptoms (SUNA) are primary headache syndromes. A growing body of literature has focused on brain magnetic resonance imaging (MRI) evidence of neurovascular compression in these syndromes.

OBJECTIVE

The objective of this article is to assess whether SUNCT is a subset of SUNA or whether the two are separate syndromes and clarify the role of neurovascular compression.

METHOD

We describe three new SUNCT cases with MRI findings of neurovascular compression and critically review published SUNCT/SUNA cases.

RESULTS

We identified 222 published SUNCT/SUNA cases. Our three patients with neurovascular compression added to the 34 cases previously described (16.9%). SUNCT and SUNA share the same clinical features and therapeutic options. At present, there is no available abortive treatment for attacks. Lamotrigine was effective in 64% of patients; topiramate and gabapentin in about one-third of cases. Of the 34 cases with neurovascular compression, seven responded to drug therapies, 16 patients underwent microvascular decompression of the trigeminal nerve (MVD) with effectiveness in 75%.

CONCLUSIONS

We suggest that SUNCT and SUNA should be considered clinical phenotypes of the same syndrome. Brain MRI should always be performed with a dedicated view to exclude neurovascular compression. The high percentage of remission after MVD supports the pathogenetic role of neurovascular compression.

Frameless linac-based stereotactic radiosurgery treatment for SUNCT syndrome targeting the trigeminal nerve and sphenopalatine ganglion

BACKGROUND

The short-lasting unilateral neuralgiform headache associated with conjunctival injection and tearing or SUNCT syndrome was first described in the 1970s. This paper is the first in the literature that describes the successful use of stereotactic radiosurgery (SRS) using a non-invasive frameless technique, targeting both the trigeminal nerve and the sphenopalatine ganglion in the management of intractable SUNCT. We also discuss the role of selecting peripheral targets in the management of this rare headache syndrome.

METHODS

Among patients treated for functional pain disorders in our radiosurgery unit using the frameless technique since August 2011, one patient with symptoms matching the International Classification of Headache Disorders-2 (ICHD-II) criteria of SUNCT syndrome was identified. The multi-disciplinary case records of this patient were retrospectively reviewed and reported.

RESULTS

Our patient had symptoms resembling the ICHD-II diagnostic criteria of SUNCT, which was refractory to medical treatment. Ninety Gy was delivered to the trigeminal root entry zone and 80 Gy was delivered to the sphenopalatine ganglion. At 16 months' follow-up, she was pain free with minimal side effects.

CONCLUSIONS

Frameless linear accelerator (linac)-based SRS targeting the trigeminal nerve and sphenopalatine ganglion remained successful in our patient at 16 months. Longer follow-up and further experience will determine the efficacy and safety of this approach. We suggest that frameless SRS is a convenient and attractive non-invasive option for patients with medically refractory SUNCT.

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.