Occipital nerve stimulation for drug-resistant chronic cluster headache: a prospective pilot study

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.

Occipital nerve stimulation for intractable chronic cluster headache or migraine: A critical analysis of direct treatment costs and complications

Background

Occipital nerve stimulation (ONS) has been shown to be effective for selected patients with intractable headache disorders. We performed a prospective critical evaluation of complications and direct treatment costs.

Methods

Twenty-seven patients with chronic cluster headache (CCH, n = 24) or chronic migraine (CM, n = 3) underwent a trial phase with bilateral ONS and subsequent implantation of a permanent generator (IPG), if responsive to treatment according to predefined criteria. Procedural and long-term complications as well as direct treatment costs of neuromodulation therapy of ONS were recorded over a mean follow-up period of 20 months (range 5–47 months).

Results

Twenty-five of 27 patients (93%) responded to treatment. Twenty-one complications in 14 patients were identified, necessitating reoperation in 13 cases. Overall treatment costs were €761,043, including hardware-related costs of €506,019, costs for primary hospital care of €210,496, and complications related to hospitalization costs of €44,528. This results in a per case-based cost of €9445 for hospitalization and €18,741 for hardware costs, totaling €28,186.

Conclusion

ONS for treatment of refractory CCH and CM is a cost-intensive treatment option with a significant complication rate. Nevertheless, patients with refractory primary headache disorders may experience substantial relief of pain attacks, and headache days, respectively.

Scientific advances in headache research: an update on neurostimulation

The pathophysiological understanding of migraine and other primary headaches has been substantially improved over the last 20 years. A milestone that paved the way for successful research was the development of the International Classification of Headache Disorders published by the International Headache Society in 1988. The classification facilitated a clear clinical diagnosis of headache disorders and allowed research efforts to be focused on clearly defined syndromes. Recent advances in the understanding of headache disorders have been driven by the availability of new research tools, such as advanced imaging techniques, genetic tools, pharmaceutical compounds and devices for electrical or magnetic stimulation. The latest scientific and clinical advances were presented at the recent European Headache and Migraine Trust International Congress (EHMTIC) in London (UK).

Occipital nerve stimulation in medically intractable, chronic cluster headache. The ICON study: Rationale and protocol of a randomised trial

Background

About 10% of cluster headache patients have the chronic form. At least 10% of this chronic group is intractable to or cannot tolerate medical treatment. Open pilot studies suggest that occipital nerve stimulation (ONS) might offer effective prevention in these patients. Controlled neuromodulation studies in treatments inducing paraesthesias have a general problem in blinding. We have introduced a new design in pain neuromodulation by which we think we can overcome this problem.

Methods/design

We propose a prospective, randomised, double-blind, parallel-group international clinical study in medically intractable, chronic cluster headache patients of high- versus low-amplitude ONS. Primary outcome measure is the mean number of attacks over the last four weeks. After a study period of six months there is an open extension phase of six months. Alongside the randomised trial an economic evaluation study is performed.

Discussion

The ICON study will show if ONS is an effective preventive therapy for patients suffering medically intractable chronic cluster headache and if there is a difference between high- and low-amplitude stimulation. The innovative design of the study will, for the first time, assess efficacy of ONS in a blinded way.

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.

Hemicrania continua: functional imaging and clinical features with diagnostic implications

This review focuses on summarizing 2 pivotal articles in the clinical and pathophysiologic understanding of hemicrania continua (HC). The first article, a functional imaging project,identifies both the dorsal rostral pons (a region associated with the generation of migraines) and the posterior hypothalamus(a region associated with the generation of cluster and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing [SUNCT]) as active during HC. The second article is a summary of the clinical features seen in a prospective cohort of HC patients that carry significant diagnostic implications. In particular, they identify a wider range of autonomic signs than what is currently included in the International Headache Society criteria (including an absence of autonomic signs in a small percentage of patients), a high frequency of migrainous features, and the presence of aggravation and/or restlessness during attacks. Wide variations in exacerbation length, frequency, pain description, and pain location (including side-switching pain) are also noted. Thus, a case is made for widening and modifying the clinical diagnostic criteria used to identify patients with HC.

Updated perspectives on occipital nerve stimulator lead migration: case report and literature review

OBJECTIVES

Patients with occipital neuralgia are often refractory to or intolerant of standard pharmacological and interventional management strategies. Although occipital nerve stimulation (ONS) may provide a unique alternative for such cases, a steep technical learning curve still exists. Lead migration (LM) is among the most challenging issues facing implanters performing ONS implantation. We present an unusual case of LM after ONS implantation and discuss technical aspects for successful revision.

METHODS

A retrospective review of medical records and fluoroscopic images was conducted to provide a case report of ONS LM and revision. A PubMed online search for the keywords occipital, stimulation, migration, and revision was also performed for literature review.

CASE REPORT

A 35-year-old man with refractory occipital neuralgia had loss of greater occipital nerve paresthesia coverage and worsened occipital headaches 11 months after ONS implantation using a midline approach. Fluoroscopic imaging confirmed lateral LM. Although most LMs occur in the lateral-to-medial trajectory, this case was unique in that LM occurred from a medial-to-lateral trajectory despite using current standard safeguards.

DISCUSSION

In an era in which reducing health care expenditures is becoming increasingly important, current complication rates could curtail future acceptance and utilization of ONS. This fact and our case report underscore the importance of a continued drive toward technical advances and a reduction in complications associated with this important treatment modality. Further prospective investigation into the mechanism of action, mechanism of complications, optimization of surgical techniques, and long-term efficacy is warranted.

Neurostimulation for chronic cluster headache

Neurostimulation techniques for the treatment of primary headache syndromes, particularly of chronic cluster headache, have received much interest in recent years. Occipital nerve stimulation (ONS) has yielded favourable clinical results and, despite the limited numbers of published cases, is becoming a routine treatment for refractory chronic cluster headache in specialized centres. Meanwhile, other promising techniques such as spinal cord stimulation (SCS) or sphenopalate ganglion stimulation have emerged. In this article the current state of clinical research for neurostimulation techniques for chronic cluster headache is reviewed.

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.

Safety and efficacy of peripheral nerve stimulation of the occipital nerves for the management of chronic migraine: results from a randomized, multicenter, double-blinded, controlled study

BACKGROUND

Chronic migraine (CM) is a debilitating neurological disorder with few treatment options. Peripheral nerve stimulation (PNS) of the occipital nerves is a potentially promising therapy for CM patients.

METHODS

In this randomized, controlled multicenter study, patients diagnosed with CM were implanted with a neurostimulation device near the occipital nerves and randomized 2:1 to active (n = 105) or sham (n = 52) stimulation. The primary endpoint was a difference in the percentage of responders (defined as patients that achieved a ≥50% reduction in mean daily visual analog scale scores) in each group at 12 weeks.

RESULTS

There was not a significant difference in the percentage of responders in the Active compared with the Control group (95% lower confidence bound (LCB) of -0.06; p = 0.55). However, there was a significant difference in the percentage of patients that achieved a 30% reduction (p = 0.01). Importantly, compared with sham-treated patients, there were also significant differences in reduction of number of headache days (Active Group = 6.1, baseline = 22.4; Control Group = 3.0, baseline = 20.1; p = 0.008), migraine-related disability (p = 0.001) and direct reports of pain relief (p = 0.001). The most common adverse event was persistent implant site pain.

CONCLUSION

Although this study failed to meet its primary endpoint, this is the first large-scale study of PNS of the occipital nerves in CM patients that showed significant reductions in pain, headache days, and migraine-related disability. Additional controlled studies using endpoints that have recently been identified and accepted as clinically meaningful are warranted in this highly disabled patient population with a large unmet medical need.

TRIAL REGISTRATION

Clinical trials.gov (NCT00615342).

Trigeminal autonomic cephalalgias: A review of recent diagnostic, therapeutic and pathophysiological developments

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders that are characterized by strictly unilateral trigeminal distribution pain occurring in association with ipsilateral cranial autonomic symptoms. This group includes cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing. These disorders are very painful, often considered to be some of the most painful conditions known to mankind, and consequently are highly disabling. They are distinguished by the frequency of attacks of pain, the length of the attacks and very characteristic responses to medical therapy, such that the diagnosis can usually be made clinically, which is important because it dictates therapy. The management of TACs can be very rewarding for physicians and highly beneficial to patients.

Neurostimulation therapies for primary headache disorders: present and future

PURPOSE OF REVIEW

Most pharmacological treatments of primary headache disorders are partially effective and have cumbersome side effects. Therapies with better efficacy and tolerance are needed. Neurostimulation techniques may have this potential. This is an attempt to summarize the latest clinical trial results published in the field.

RECENT FINDINGS

Hypothalamic deep brain stimulation is effective in drug-resistant chronic cluster headache (drCCH) but not riskless. Recent anatomical MRI studies indicate that the effective stimulation sites are rather widespread. Occipital nerve stimulation (ONS) seems to be effective in up to 76% of drCCH patients and its benefit long-lasting. A minority of patients are able to abandon preventive drugs. Its mechanism of action appears nonspecific. In chronic migraine, randomized controlled trials of ONS showed recently encouraging results, but long-term studies are missing. An ongoing sham-controlled trial suggests sphenopalatine ganglion neurostimulation (SPGS) efficacy in drCCH acute treatment, but possibly also in preventive therapy. Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) modulate cortical excitability and connectivity. TMS could prevent headache when applied over the occipital cortex during the migraine aura. Repetitive TMS and tDCS have provided mixed results in a few small studies and warrant further trials.

SUMMARY

Neurostimulation therapies inaugurate a new era in headache management and offer a promising alternative to medications. Future studies are necessary to provide evidence-based efficacy data, knowledge on their mode of action and information about their pharmaco-economic advantages.

Occipital nerve stimulation in primary headache syndromes

Chronic daily headache is a major worldwide health problem that affects 3-5% of the population and results in substantial disability. Advances in the management of headache disorders have meant that a substantial proportion of patients can be effectively treated with medical treatments. However, a significant minority of these patients are intractable to conventional medical treatments. Occipital nerve stimulation (ONS) is emerging as a promising treatment for patients with medically intractable, highly disabling chronic headache disorders, including migraine, cluster headache and other less common headache syndromes. Open-label studies have suggested that this treatment modality is effective and recent controlled trial data are also encouraging. The procedure is performed using several technical variations that have been reviewed along with the complications, which are usually minor and tolerable. The mechanism of action is poorly understood, though recent data suggest that ONS could restore the balance within the impaired central pain system through slow neuromodulatory processes in the pain neuromatrix. While the available data are very encouraging, the ultimate confirmation of the utility of a new therapeutic modality should come from controlled trials before widespread use can be advocated; more controlled data are still needed to properly assess the role of ONS in the management of medically intractable headache disorders. Future studies also need to address the variables that are predictors of response, including clinical phenotypes, surgical techniques and stimulation parameters.

Long-term outcome in occipital nerve stimulation patients with medically intractable primary headache disorders

INTRODUCTION

€‚ Occipital nerve stimulation (ONS) may provide relief for refractory headache disorders. However, scant data exist regarding long-€term ONS outcomes.

METHODS

€‚ The methods used were retrospective review of the medical records of all (nonindustry study) patients who were trialed and implanted with occipital nerve stimulator systems at our institution, followed by a phone interview. Up to three attempts were made to contact each patient, and those who were contacted were given the opportunity to participate in a brief phone interview regarding their ONS experience. Data for analysis were gleaned from both the phone interview and the patient's medical records.

RESULTS

€‚ Twenty-nine patients underwent a trial of ONS during the 8.5-€year study period. Three patients did not go on to permanent implant, 12 could not be contacted, and 14 participated in the phone interview. Based upon the phone interview (if the patient was contacted) or chart review, ONS was deemed successful in five of the 12 migraine, four of the five cluster headache, and five of the eight miscellaneous headache patients, and therapy was documented as long as 102 months. In one of the 26 patients, success of ONS could not be determined. Among patients deemed to have successful outcomes, headache frequency decreased by 18%, severity by 27%, and migraine disability score by 50%. Fifty-€eight percent of patients required at least one lead revision.

DISCUSSION

€‚ These results, although limited by their retrospective nature, suggest that ONS can be effective long term despite technical challenges. The number of patients within each headache subtype was insufficient to draw conclusions regarding the differential effect of ONS.

CONCLUSIONS

€‚ Randomized controlled long-€term studies in specific, intractable, primary headache disorders are indicated.

[Neurostimulation for treatment of headaches]

Only a small portion of patients with primary headaches are refractory to treatment concerning relief of headache episodes and prophylactic therapy of headaches. New methods of central and peripheral neurostimulation have been developed for these patients during the last few years and experience was mostly gained in small case series. The following overview gives a description of new stimulation methods, such as deep brain stimulation, occipital nerve stimulation, vagal nerve stimulation, neurostimulation of the sphenopalatine ganglion and transcranial magnetic stimulation.

Management of cluster headache

The prevalence of cluster headache is 0.1% and cluster headache is often not diagnosed or misdiagnosed as migraine or sinusitis. In cluster headache there is often a considerable diagnostic delay - an average of 7 years in a population-based survey. Cluster headache is characterized by very severe or severe orbital or periorbital pain with a duration of 15-180 minutes. The cluster headache attacks are accompanied by characteristic associated unilateral symptoms such as tearing, nasal congestion and/or rhinorrhoea, eyelid oedema, miosis and/or ptosis. In addition, there is a sense of restlessness and agitation. Patients may have up to eight attacks per day. Episodic cluster headache (ECH) occurs in clusters of weeks to months duration, whereas chronic cluster headache (CCH) attacks occur for more than 1 year without remissions. Management of cluster headache is divided into acute attack treatment and prophylactic treatment. In ECH and CCH the attacks can be treated with oxygen (12 L/min) or subcutaneous sumatriptan 6 mg. For both oxygen and sumatriptan there are two randomized, placebo-controlled trials demonstrating efficacy. In both ECH and CCH, verapamil is the prophylactic drug of choice. Verapamil 360 mg/day was found to be superior to placebo in one clinical trial. In clinical practice, daily doses of 480-720 mg are mostly used. Thus, the dose of verapamil used in cluster headache treatment may be double the dose used in cardiology, and with the higher doses the PR interval should be checked with an ECG. At the start of a cluster, transitional preventive treatment such as corticosteroids or greater occipital nerve blockade can be given. In CCH and in long-standing clusters of ECH, lithium, methysergide, topiramate, valproic acid and ergotamine tartrate can be used as add-on prophylactic treatment. In drug-resistant CCH, neuromodulation with either occipital nerve stimulation or deep brain stimulation of the hypothalamus is an alternative treatment strategy. For most cluster headache patients there are fairly good treatment options both for acute attacks and for prophylaxis. The big problem is the diagnosis of cluster headache as demonstrated by the diagnostic delay of 7 years. However, the relatively short-lasting attack of pain in one eye with typical associated symptoms should lead the family doctor to suspect cluster headache resulting in a referral to a neurologist or a headache centre with experience in the treatment of cluster headache.

Italian guidelines for primary headaches: 2012 revised version

The first edition of the Italian diagnostic and therapeutic guidelines for primary headaches in adults was published in J Headache Pain 2(Suppl. 1):105-190 (2001). Ten years later, the guideline committee of the Italian Society for the Study of Headaches (SISC) decided it was time to update therapeutic guidelines. A literature search was carried out on Medline database, and all articles on primary headache treatments in English, German, French and Italian published from February 2001 to December 2011 were taken into account. Only randomized controlled trials (RCT) and meta-analyses were analysed for each drug. If RCT were lacking, open studies and case series were also examined. According to the previous edition, four levels of recommendation were defined on the basis of levels of evidence, scientific strength of evidence and clinical effectiveness. Recommendations for symptomatic and prophylactic treatment of migraine and cluster headache were therefore revised with respect to previous 2001 guidelines and a section was dedicated to non-pharmacological treatment. This article reports a summary of the revised version published in extenso in an Italian version.

Occipital nerve block is effective in craniofacial neuralgias but not in idiopathic persistent facial pain

Occipital nerve block (ONB) has been used in several primary headache syndromes with good results. Information on its effects in facial pain is sparse. In this chart review, the efficacy of ONB using lidocaine and dexamethasone was evaluated in 20 patients with craniofacial pain syndromes comprising 8 patients with trigeminal neuralgia, 6 with trigeminal neuropathic pain, 5 with persistent idiopathic facial pain and 1 with occipital neuralgia. Response was defined as an at least 50% reduction of original pain. Mean response rate was 55% with greatest efficacy in trigeminal (75%) and occipital neuralgia (100%) and less efficacy in trigeminal neuropathic pain (50%) and persistent idiopathic facial pain (20%). The effects lasted for an average of 27 days with sustained benefits for 69, 77 and 107 days in three patients. Side effects were reported in 50%, albeit transient and mild in nature. ONBs are effective in trigeminal pain involving the second and third branch and seem to be most effective in craniofacial neuralgias. They should be considered in facial pain before more invasive approaches, such as thermocoagulation or vascular decompression, are performed, given that side effects are mild and the procedure is minimally invasive.

[Peripheral nerve stimulation in the treatment of various types of headache]

BACKGROUND AND OBJECTIVE

Headache has a great impact on patients' quality of life and in industrialized countries there is economic impact as well. One of the pathophysiologic theories to explain headache is activation of afferent C2-C3 nerve fibers. Afferent peripheral nerve stimulation by occipital nerve provocation at C2-C3 seems to alleviate headache by acting on the trigeminocervical complex, which would largely explain the effectiveness of this modality. The aim of this study was to describe peripheral nerve stimulation as an alternative therapy in patients who do not respond to other headache treatments.

MATERIAL AND METHODS

Multicenter retrospective study between April 2005 and May 2009, analyzing cases of patients treated with nerve stimulation for severe chronic headache. In all patients the medical history included type of headache, intensity of pain on a numerical scale, medical treatment used, and number of headache episodes. We recorded the percentage of patients with negative tests. Patients implanted with a generator assessed effectiveness on the numerical scale; we analyzed the percentage of perceived improvement at 1, 3, 6, and 12 months. We also analyzed the extent of coverage provided by the electrodes, patient satisfaction, reduction in the number of episodes and medication, and complications.

RESULTS

Of 31 patients, 87% had positive results, with a significant decrease in pain from baseline (P < .001); 85.2% reported sustained improvement of > 50%, and 96.3% reported a decrease of > 2 points on the pain scale. All patients expressed satisfaction during the period of follow-up. Fifty-six percent had no headaches after a year and 47% had stopped taking medication. The most frequent complication was electrode migration.

Occipital nerve stimulation for medically refractory hypnic headache

OBJECTIVE

Hypnic headache is a rare, primary headache disorder that exclusively occurs regularly during sleep. We present a case of hypnic headache successfully managed with occipital nerve stimulation.

MATERIALS AND METHODS

A 64-year-old female presented with a four-year history of a right occipital headache that regularly awakened her from sleep. The headache, which was dull and throbbing, would awaken her regularly at 4:00 am, five hours after bedtime at 11:00 pm. No photophobia, nausea or vomiting, lacrimation, or other autonomic symptoms were present. The headache was refractory to various medical treatments, including indomethacin, flunarizine, propranolol. She underwent a trial of occipital nerve stimulation with a lead electrode using a medial approach.

RESULTS

During the ten-day trial stimulation, she reported almost complete relief from hypnic headache. Chronic occipital nerve stimulation replicated the trial results. The attacks of hypnic headache recurred in one year with loss of stimulation-induced paresthesia; a subsequent x-ray showed electrode migration. After revision of the electrode to the original location, the effectiveness of the occipital nerve stimulation against hypnic headache was achieved again, and this effect has been consistent through 36 months of follow-up.

CONCLUSION

Occipital nerve stimulation was effective in a patient with chronic, refractory hypnic headache.

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.

Supraorbital transcutaneous neurostimulation has sedative effects in healthy subjects

Background

Transcutaneous neurostimulation (TNS) at extracephalic sites is a well known treatment of pain. Thanks to recent technical progress, the Cefaly^® device now also allows supraorbital TNS. During observational clinical studies, several patients reported decreased vigilance or even sleepiness during a session of supraorbital TNS. We decided therefore to explore in more detail the potential sedative effect of supraorbital TNS, using standardized psychophysical tests in healthy volunteers.

Methods

We performed a double-blind cross-over sham-controlled study on 30 healthy subjects. They underwent a series of 4 vigilance tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale, d2 test). Each subject was tested under 4 different experimental conditions: without the neurostimulation device, with sham supraorbital TNS, with low frequency supraorbital TNS and with high frequency supraorbital TNS.

Results

As judged by the results of three tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale) there was a statistically significant (p < 0.001) decrease in vigilance and attention during high frequency TNS, while there were no changes during the other experimental conditions. Similarly, performance on the d2 test was impaired during high frequency TNS, but this change was not statistically significant.

Conclusion

Supraorbital high frequency TNS applied with the Cefaly^® device decreases vigilance in healthy volunteers. Additional studies are needed to determine the duration of this effect, the underlying mechanisms and the possible relation with the stimulation parameters. Meanwhile, this effect opens interesting perspectives for the treatment of hyperarousal states and, possibly, insomnia.

Treatment of refractory chronic cluster headache by chronic occipital nerve stimulation

Background: Greater occipital nerve stimulation (ONS) has been recently proposed to treat severe chronic cluster headache patients (CCH) refractory to medical treatment. We report the results of a French multidisciplinary cohort study.

Methods: Thirteen CCH patients were operated and data were collected prospectively. All of them suffered from CCH according to the International Headache Society classification, lasting for more than 2 years, refractory to pharmacological prophylactic treatment with adequate trials, with at least one daily attack. Chronic ONS was delivered through a subcutaneous occipital electrode connected to an implanted generator, in order to induce paraesthesias perceived locally in the lower occipital region.

Results: After surgery (mean follow-up 14,6 months), the mean attack frequency and intensity decreased by 68% and 49%, respectively. At last follow-up, 10/13 patients were considered as responders (improvement >50%). Prophylactic treatment could be stopped or reduced in 8/13 cases. Local infection occurred in one patient, leading to hardware removal.

Conclusions: Our data confirmed the results of the 36 similar cases reported in the literature, suggesting that ONS may act as a prophylactic treatment in chronic CH. Considering their respective risks, ONS should be proposed before deep brain stimulation in severe refractory CCH patients.

High cervical spinal cord stimulation for chronic cluster headache

BACKGROUND

Cluster headache (CH) is the most painful and debilitating primary headache syndrome. Conventional treatment combines acute and prophylactic drugs. Also with maximal therapy a substantial proportion of patients do not experience a meaningful prevention or pain relief. Recent case series and early trials have suggested that occipital nerve stimulation can be very effective in the management of intractable CH.

METHODS

Seven patients with medically intractable chronic cluster headache were implanted with high cervical epidural electrodes. After a median test phase of 10 days (range 4-19 days) an impulse generator was implanted subcutaneously. Mean follow up was 23 months (median 12 months, range 3-78 months).

RESULTS

All patients showed significant treatment effects. In all patients, improvement occurred immediately after electrode implantation. The mean attack frequency decreased, as well as the mean duration and intensity of attacks. Also, depression, anxiety, and pain-related impairment scores decreased and medication intake was markedly reduced.

CONCLUSIONS

In this prospective series, high cervical spinal cord stimulation shows an effect size equal or larger than occipital nerve stimulation with immediate onset after surgery and may serve as a valuable additional treatment option of intractable cluster headache in the future.

[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.

[Hypothalamic deep brain stimulation for treatment of cluster headache]

Extremely severe, unilateral, recurrent facial pain and headache, accompanied by autonomic symptoms and signs, can be identified as cluster headache attacks (CH). Despite optimal pharmacological treatment, 20% of patients will not achieve satisfactory improvement. The severity of pain is so extreme that CH has been a cause of multiple suicidal attempts among patients ineffectively treated because of CH. Hypermetabolism of ipsilateral posterior hypothalamus observed in PET studies led to multiple attempts of deep brain stimulation (DBS) utilization in CH treatment. The authors present current opinions about DBS treatment in CH. A socioeconomic analysis of neuromodulatory treatment of CH is presented.

Central modulation in cluster headache patients treated with occipital nerve stimulation: an FDG-PET study

BACKGROUND

Occipital nerve stimulation (ONS) has raised new hope for drug-resistant chronic cluster headache (drCCH), a devastating condition. However its mode of action remains elusive. Since the long delay to meaningful effect suggests that ONS induces slow neuromodulation, we have searched for changes in central pain-control areas using metabolic neuroimaging.

METHODS

Ten drCCH patients underwent an 18FDG-PET scan after ONS, at delays varying between 0 and 30 months. All were scanned with ongoing ONS (ON) and with the stimulator switched OFF.

RESULTS

After 6-30 months of ONS, 3 patients were pain free and 4 had a ≥ 90% reduction of attack frequency (responders). In all patients compared to controls, several areas of the pain matrix showed hypermetabolism: ipsilateral hypothalamus, midbrain and ipsilateral lower pons. All normalized after ONS, except for the hypothalamus. Switching the stimulator ON or OFF had little influence on brain glucose metabolism. The perigenual anterior cingulate cortex (PACC) was hyperactive in ONS responders compared to non-responders.

CONCLUSIONS

Metabolic normalization in the pain neuromatrix and lack of short-term changes induced by the stimulation might support the hypothesis that ONS acts in drCCH through slow neuromodulatory processes. Selective activation in responders of PACC, a pivotal structure in the endogenous opioid system, suggests that ONS could restore balance within dysfunctioning pain control centres. That ONS is nothing but a symptomatic treatment might be illustrated by the persistent hypothalamic hypermetabolism, which could explain why autonomic attacks may persist despite pain relief and why cluster attacks recur shortly after stimulator arrest. PET studies on larger samples are warranted to confirm these first results.

Occipital nerve stimulation for the treatment of intractable chronic migraine headache: ONSTIM feasibility study

BACKGROUND

Medically intractable chronic migraine (CM) is a disabling illness characterized by headache ≥15 days per month.

METHODS

A multicenter, randomized, blinded, controlled feasibility study was conducted to obtain preliminary safety and efficacy data on occipital nerve stimulation (ONS) in CM. Eligible subjects received an occipital nerve block, and responders were randomized to adjustable stimulation (AS), preset stimulation (PS) or medical management (MM) groups.

RESULTS

Seventy-five of 110 subjects were assigned to a treatment group; complete diary data were available for 66. A responder was defined as a subject who achieved a 50% or greater reduction in number of headache days per month or a three-point or greater reduction in average overall pain intensity compared with baseline. Three-month responder rates were 39% for AS, 6% for PS and 0% for MM. No unanticipated adverse device events occurred. Lead migration occurred in 12 of 51 (24%) subjects.

CONCLUSION

The results of this feasibility study offer promise and should prompt further controlled studies of ONS in CM.

Pharmacotherapy of cluster headache

IMPORTANCE OF THE FIELD

Cluster headache belongs to the trigemino-autonomic cephalgias and is one of the most devastating idiopathic pain syndromes. Despite its extreme severity and its prevalence of about 0.1%, little attention has been paid to this painful syndrome by either basic or clinical research.

AREAS COVERED IN THIS REVIEW

All clinical trials on the acute and prophylactic drug treatment of cluster headache are reviewed, including review articles and book chapters.

WHAT THE READER WILL GAIN

The treatment of cluster headache is based on acute and prophylactic drug treatment. Oxygen inhalation, subcutaneous or intranasal sumatriptan, and intranasal zolmitriptan are recommended to stop an attach. For prophylaxis, verapamil is drug of first choice. Other drugs efficacious in cluster headache are steroids, lithium, some anticonvulsants and methysergide. Recently, interventional procedures have been studied for the treatment of refractory cluster headache. In the future, new anticonvulsants and unconventional ways of immunotherapy should be evaluated.

TAKE HOME MESSAGE

In most cases, cluster headache can be treated sufficiently (i.e., with sufficient quality of life) by an individual concept of acute and prophylactic drug treatment.

Repositioning of supraorbital nerve stimulation electrode using retrograde needle insertion: a technical note

INTRODUCTION

With growing interest and acceptance of peripheral nerve stimulation (PNS) approach, there is now an increasing need in developing clear procedural details to resolve frequent complications and minimize associated tissue injury. Migration and suboptimal positioning of PNS electrodes are one of the most commonly observed complications of PNS approach.

MATERIALS AND METHODS

We present a simple technique for repositioning a supraorbital electrode using retrograde insertion of introducer needle that allows one to place percutaneous (cylindrical) PNS electrode into appropriate anatomical location with minimal additional injury to surrounding tissues.

RESULTS

This approach has been successfully used in multiple cases. An illustrative case of electrode revision with proposed technique is described in detail.

CONCLUSION

This technically simple approach to repositioning of cylindrical supraorbital electrodes using retrograde needle insertion eliminates the need for a more elaborate and invasive procedure. The technique can be used for electrode repositioning in most PNS applications.