Neurostimulation for Primary Headache Disorders, Part 1: Pathophysiology and Anatomy, History of Neuromodulation in Headache Treatment, and Review of Peripheral Neuromodulation in Primary Headaches

Primary headache disorders: From pathophysiology to neurostimulation therapies

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

Transcranial magnetic stimulation maps the neurophysiology of chronic noncancer pain: A scoping review

BACKGROUND

Chronic noncancer pain is a global public health challenge. It is imperative to identify biological markers ("biomarkers") to understand the mechanisms underlying chronic pain and to monitor pain over time and after interventions. Transcranial magnetic stimulation (TMS) is a promising method for this purpose.

OBJECTIVES

To examine differences in TMS-based outcomes between persons with chronic pain and healthy controls (HCs) and/or before versus after pain-modulating interventions and relationships between pain measures and TMS outcomes; To summarize the neurophysiological mechanisms underlying chronic pain as identified by TMS.

METHODS

We searched the PubMed database for literature from January 1, 1985, to June 9, 2020, with the keywords "pain" and "transcranial magnetic stimulation." Eligible items included original studies of adult human participants with pain lasting for ≥ 6 months. We completed a narrative synthesis of the study findings stratified by chronic pain etiology (primary pain, neuropathic pain, and secondary musculoskeletal pain).

RESULTS

The search yielded 1265 records. The final 12 articles included 244 patients with chronic pain (192 females, aged 35-65 years) and 169 HCs (89 females, aged 28-59 years). Abnormalities in TMS outcomes that reflect GABAergic and glutamatergic activities were associated with many of the disorders studied and were distinct for each pain etiology. Chronic primary pain is characterized by reduced intracortical inhibition and corticospinal excitability, chronic neuropathic pain shows evidence of increased excitation and disinhibition, and chronic secondary musculoskeletal pain involves low corticospinal excitability.

DISCUSSION

TMS could be a useful tool for delineating the neurophysiological underpinnings of chronic pain syndromes.

Non-invasive brain neuromodulation techniques for chronic low back pain

Structural and functional changes of the brain occur in many chronic pain conditions, including chronic low back pain (CLBP), and these brain abnormalities can be reversed by effective treatment. Research on the clinical applications of non-invasive brain neuromodulation (NIBS) techniques for chronic pain is increasing. Unfortunately, little is known about the effectiveness of NIBS on CLBP, which limits its application in clinical pain management. Therefore, we summarized the effectiveness and limitations of NIBS techniques on CLBP management and described the effects and mechanisms of NIBS approaches on CLBP in this review. Overall, NIBS may be effective for the treatment of CLBP. And the analgesic mechanisms of NIBS for CLBP may involve the regulation of pain signal pathway, synaptic plasticity, neuroprotective effect, neuroinflammation modulation, and variations in cerebral blood flow and metabolism. Current NIBS studies for CLBP have limitations, such as small sample size, relative low quality of evidence, and lack of mechanistic studies. Further studies on the effect of NIBS are needed, especially randomized controlled trials with high quality and large sample size.

Non-invasive neuromodulation in the acute treatment of migraine: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

A systematic review and meta-analysis was performed to determine the efficacy of non-invasive neuromodulation modalities for the treatment of acute migraine.

BACKGROUND

Although pharmacological treatments are the gold standard for the management of acute migraine, some patients may require non-pharmacological treatment options. Non-invasive neuromodulation may provide an alternative, and techniques include transcranial magnetic stimulation (TMS), non-invasive vagal nerve stimulation (nVNS), non-painful remote electrical stimulation (NRES), and external trigeminal nerve stimulation (e-TNS).

METHODS

This systematic review and meta-analysis was performed following PRISMA guidelines. We searched PUBMED, EMBASE, ClinicalTrials.gov, Cochrane Center Register of Controlled Trials, and LILACS databases. We included randomized controlled clinical trials studying patients with migraine treated with any form of non-invasive neuromodulation. Primary outcome was pain freedom within 2 h post-treatment. Secondary outcomes were pain relief within 2-h post-treatment and sustained pain freedom and sustained pain relief 48 h post-treatment.

RESULTS

Pooled analysis demonstrated a significant effect of non-invasive neuromodulation on pain-free rates within 2 h (RR, 1.66; 95% CI, 1.35 to 2.05; P < 0.00001) and pain relief rates within 2 h (RR, 1.52; 95% CI, 1.13 to 2.05; P = 0.005) post-treatment. Non-invasive neuromodulation had no significant effect on sustained pain freedom at 48 h (RR, 1.56; 95% CI, 0.68 to 3.59; P = 0.29) or sustained pain relief at 48 h (RR, 1.47; 95% CI, 0.57 to 3.77; P = 0.43) after administration.

CONCLUSION

Neuromodulation has demonstrated some efficacy in acute migraine management and may be considered in the treatment paradigm of acute migraine in patients with contraindications to pharmacological therapies.

Effect of Occipital Nerve Stimulation (ONS) on the Orbicularis Oculi Reflex Triggered by a Standardized Air Flow in Patients with Chronic Migraine-A Prospective, Randomized, Interventional Study

Introduction

Occipital nerve stimulation (ONS) is a specific form of peripheral neuromodulation used in the treatment of chronic pain disorders. A particular field of application is in the therapy of treatment-refractory headaches, especially of chronic migraine. The precise mode of action is unknown. It is presumed that central and peripheral sensitization are reduced in patients with chronic headache. The aim of this study was to examine the effect of ONS on pain-modulatory mechanisms in the trigeminocervical area in patients with chronic migraine.

Methods

In a balanced repeated measurements design in eight patients with chronic migraine with and without active ONS, we analyzed which effects ONS had on the orbicularis oculi reflex dynamically elicited by corneal air flow.

Results

The orbicularis oculi reflex in active ONS (7.38 ± 20.14 eyelid closures/minute) compared to inactive ONS (18.73 ± 14.30 eyelid closures/minute) is significantly reduced (p = 0.021).

Conclusions

The results show that under active ONS compared to inactive ONS in patients with chronic migraine, the orbicularis oculi reflex, dynamically triggered by a standardized air flow, is significantly reduced. This suggests that ONS is able to directly counteract the trigeminally mediated central sensitization in chronic migraine and protectively reduce the effects of aversive peripheral stimulation.

Occipital Nerve Stimulation in Chronic Migraine: The Relationship Between Perceived Sensory Quality, Perceived Sensory Location, and Clinical Efficacy-A Prospective, Observational, Non-Interventional Study

Introduction

Occipital nerve stimulation (ONS) is used to treat therapy-resistant chronic migraine. Clinical use has resulted in a wide intraindividual and interindividual variation of clinical efficacy. The aim of this study was to analyze a potential relationship between sociodemographic variables, headache parameters, perceived sensory quality, perceived sensory location, as well as clinical efficacy.

Methods

Thirty-two subjects (21.9% male, mean age 45.77 years) suffering from chronic migraine refractory to other treatment and therefore treated with ONS were included in this study. We used a computer-based imaging method for mapping the ONS-induced perceived sensory location, the perceived spatial sensory field size, as well as the perceived sensory quality in a long-term course over 21 months in weekly time intervals. Additionally, the effect of ONS on the migraine headache was documented weekly by the participants using a verbal rating scale. Over the observation period, a total of 808 individual weekly data sets were recorded and a potential relationship between ONS-induced perceptions and headache parameters could be analyzed.

Results

We found that 48.9% of stimulation intervals were reported as effective by patients. Women displayed a significantly higher responder rate than men. The reported effectiveness did not differ depending on age, the average number of migraine days per month, the MIDAS score, or the duration of the migraine disorder prior to ONS treatment. Implantation with trial period led to significantly lower responder rates than without the trial period. The most frequently perceived sensory quality of “tingling” was found significantly more frequently in non-responders than in responders. Responders displayed significantly lower pleasantness scores for their reported perceptions than non-responders. Sensations that were spatially perceived above the line connecting the external acoustic meati with the external occipital protuberance (MOP line) led to patients reporting a positive clinical effect significantly more frequently than sensations spatially perceived below the MOP line. Spatially small fields of sensory perception were correlated with a higher responder rate than those covering broader areas.

Conclusions

The ONS-induced sensory location, the size of the spatial sensory field, as well as the sensory quality are significantly correlated with the reported clinical effectiveness. The results suggest that besides surgical technique, the individual and continuous programming of the stimulation parameters is clinically relevant in increasing the therapeutic effectiveness.

Non-invasive Brain Stimulation in Pediatric Migraine: A Perspective From Evidence in Adult Migraine

Pediatric migraine remains still a challenge for the headache specialists as concerns both diagnostic and therapeutic aspects. The less ability of children to describe the exact features of their migraines and the lack of reliable biomarker for migraine contribute to complicate the diagnostic process. Therefore, there's need for new effective tools for supporting diagnostic and therapeutic approach in children with migraine. Recently, promising results have been obtained in adult headache by means of application of neurostimulation techniques both for investigating pathophysiological mechanisms and also for therapeutical applications. Non-invasive brain stimulation (NIBS) techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) indeed proved to be generally safe and showing also some evidence of efficacy particularly for the symptomatic treatment. On such basis, in the last years increasing interest is rising in scientific pediatric community to evaluate the potential of such approaches for treatment pediatric headaches, particularly in migraine, even if the evidence provided is still very poor. Here we present a perspective for application of TMS and tDCS technique in children migraine principally based on evidence coming by studies in adults.

Supraorbital Occipital Circumferential Stimulation for the Treatment of Refractory Chronic Primary Headache: A Case Series

BACKGROUND

Patients with refractory chronic primary headache disorders have extremely debilitating symptoms, severe comorbidities (e.g., anxiety, depression), and a significant reduction in quality of life. The headaches are extremely difficult to treat, as they are often refractory to pharmacologic and procedural interventions. Neuromodulation with stimulation of the occipital and supraorbital nerves has been proposed as a viable treatment for these refractory headaches. We retrospectively review the long-term (33.5 ± 20 months) results of supraorbital occipital nerve circumferential stimulation (SOCS) in patients with chronic primary headache disorders.

METHODS

We retrospectively review 25 patients who were evaluated for SOCS for chronic primary headache disorders from 2010 to 2017 at a single institution with a single neurosurgeon.

RESULTS

Of these 25 patients, 14 saw benefits to their trial stage of stimulation and underwent full implantation. A total 3 patients were excluded from further analysis because of having <2 months of follow-up or discordant data. Of the 11 patients analyzed, there was an overall response rate (≥50% pain reduction) of 82%. The average preoperative 10-point pain score dropped from 7.1 ± 1.6 to a postoperative score of 3.3 ± 2.1. However, there was a high rate of complications including infection, erosion, and loss of effect.

CONCLUSIONS

The results (82% response) suggest that SOCS may be an effective treatment and should be studied more extensively. Occipital nerve stimulation alone has shown 40% to 50% response rate in published studies. However, the relatively high complication rate highlights an obstacle for the approach for the treatment of refractory headache disorders and room for device optimization.

Combination of flunarizine and transcutaneous supraorbital neurostimulation improves migraine prophylaxis

OBJECTIVE

This study is aimed to access the efficacy and safety of combination therapy of flunarizine plus transcutaneous supraorbital neurostimulation (tSNS) compared with either flunarizine or tSNS alone for migraine prophylaxis.

METHODS

Patients with episodic migraine were enrolled and randomized into 3 groups. Flunarizine 5 mg per day, or tSNS for 20 minutes daily or combination of both were prescribed consecutively for 3 months. The primary outcome measures were changes in migraine days and 50% responder rate of monthly migraine days. Secondary outcome measures were the changes in migraine intensity and intake of rescue medication. Finally, satisfaction to treatment and adverse effect were evaluated as well.

RESULTS

A total of 154 were randomized and included in the analysis. After 3 months, the monthly migraine days were decreased in 3 groups and more significant in the combination group. The 50% responder rate was significantly higher (78.43%) in the combination therapy than monotherapy of flunarizine (46.15%) or tSNS (39.22%) alone. Greater reduction of migraine intensity and intake of rescue medication was observed in combination group. There was no difference of adverse events between flunarizine group and combination group (P = .89).

CONCLUSION

Adding tSNS to flunarizine can improve the therapeutic efficacy of migraine prophylaxis without increasing the adverse effects. In addition, tSNS is effective and safe for migraine treatment and can be a valid option for migraineurs who are reluctant to take oral medications or for patients who experience a low-migraine frequency and/or intensity that prophylactic therapy is not indicated but desire to acquire medical intervention.

Selective Scalp Nerve Block: A Useful Technique With Tissue Expansion in Postburn Pediatric Alopecia

BACKGROUND

Scalp defects can be reconstructed either with skin graft, local flaps, free flaps, or tissue expansion. Tissue expanders have been proved to be fruitful in the pediatric population. Scalp expansion has proved to be useful in the reconstruction of posttraumatic and postburn alopecic defects. Selective nerve block can be added for attenuation of sympathetic stimulation and decrease surgical stress in cranial surgeries. In this study, a comparison was done between using selective nerve block and without selective nerve block in both stages of tissue expansion procedure.

PATIENTS AND METHODS

This study included 32 different children who underwent tissue expansions in the management of postburn alopecia. Pediatric patients presented with postburn alopecia of the scalp with mature scar were included in this work.

RESULTS

Postoperative analgesics were less in children who had received scalp block, whereas it was shorter in patients who did not receive any scalp block. Meperidine consumption was much more less in patients who received selective scalp nerve block. Pain score was markedly decreased in children who had received selective scalp nerve block in the immediate postoperative period. Children who received scalp block showed marked attenuation in the surgical stress responses with minimal changes in heart rate and mean arterial blood pressure after skin incision.

CONCLUSIONS

Scalp nerve block is considered an excellent choice for postoperative pain control with less need for opioid analgesia.

Effects of external trigeminal nerve stimulation (eTNS) on laser evoked cortical potentials (LEP): A pilot study in migraine patients and controls

Background

Transcutaneous external supraorbital nerve stimulation has emerged as a treatment option for primary headache disorders, though its action mechanism is still unclear.

Study aim

In this randomized, sham-controlled pilot study we aimed to test the effects of a single external transcutaneous nerve stimulation session on pain perception and cortical responses induced by painful laser stimuli delivered to the right forehead and the right hand in a cohort of migraine without aura patients and healthy controls.

Methods

Seventeen migraine without aura patients and 21 age- and sex-matched controls were selected and randomly assigned to a real or sham external transcutaneous nerve stimulation single stimulation session. The external transcutaneous nerve stimulation was delivered with a self-adhesive electrode placed on the forehead and generating a 60 Hz pulse at 16 mA intensity for 20 minutes. For sham stimulation, we used 2 mA intensity. Laser evoked responses were recorded from 21 scalp electrodes in basal condition (T0), during external transcutaneous nerve stimulation and sham stimulation (T1), and immediately after these (T2). The laser evoked responses were analyzed by LORETA software.

Results

The real external transcutaneous nerve stimulation reduced the trigeminal N2P2 amplitude in migraine and control groups significantly in respect to placebo. The real stimulation was associated with lower activity in the anterior cingulate cortex under trigeminal laser stimuli. The pattern of LEP-reduced habituation was reverted by real and sham transcutaneous stimulation in migraine patients.

Conclusions

The present results could suggest that the external transcutaneous nerve stimulation may interfere with the threshold and the extent of trigeminal system activation, with a mechanism of potential utility in the resolution and prevention of migraine attacks.

Positional Relations of the Cervical Vagus Nerve Revisited

OBJECTIVES

The cervical part of the vagus nerve (CVN) has become an important target for stimulation therapy to treat epilepsy and psychiatric conditions. For this purpose, the CVN is visualized in the carotid sheath, assuming it to be localized dorsomedially between the carotid artery (CA) and the internal jugular vein (JV). The aim of our morphological study was therefore to revisit the CVN relationships to the CA and JV, hypothesizing it to have common variations to this classical textbook anatomy.

MATERIALS AND METHODS

Positional relations of the CVN, CA and JV were investigated in the carotid sheath of 35 cadavers at the C3 to C6 level. Positional relations of the CVN, CA and JV were documented on the basis of a 3 × 3 chart.

RESULTS

Eighteen different arrangements of the CVN, CA and JV were observed. The typical topographic relationship of the CVN dorsomedially between the CA and JV was only found in 42% of all cases. The CVN was located dorsally or (dorso-)laterally to the CA in 80% and dorsally or (dorso-)medially of the JV in 96% of all cases.

CONCLUSIONS

Classical textbook anatomy of the CVN is only present in a minority of cases. Positional variations in contrast to textbook anatomy are considerably more frequent than previously described, which might be a hypothetical morphological explanation for the lack of efficacy or side effects of CVN stimulation. Furthermore, the position of the CVN relative to the internal jugular vein is more consistent than to the CA.

Non-invasive transcutaneous Supraorbital Neurostimulation (tSNS) using Cefaly® device in prevention of primary headaches

Headaches are one of the most common pain syndromes experienced by adult patients. International Classification of Headache Disorders identifies about 300 different entities. Primary headaches (migraine, tension-type headache, trigeminal autonomic cephalalgias, other primary headaches) has the common occurrence. Although effective treatment of these disorders is possible, it is inefficient or poorly tolerated in some patients. Neuromodulation methods, being element of multimodal treatment, provide an additional treatment option in pharmacotherapy-refractory patients. Both invasive and non-invasive stimulation methods are used. The non-invasive techniques is transcutaneous nerve stimulation using Cefaly^® device. In this study, Cefaly^® was used as prevention treatment in patients with pharmacotherapy-refractory headaches. This device is indicated for the prophylactic treatment of episodic primary headaches. A total of 91-patients (30 without and 61 with tSNS) were enrolled in the study, including 60-patients with migraine and 31-patients with other primary headaches. Ten courses of non-invasive peripheral (supraorbitral/supratrochlear) nerves stimulation were delivered to 57-patients; in the remaining 4 patients, the treatment was abandoned due to poor tolerance. Patients were observed for 30 days after stimulation treatment. Compared to the pre-treatment period, the reduction in the intensity of pain was observed in both the migraine group and patients with other types of headaches; this included the number of pain episodes being reduced by half, with simultaneous reduction in average pain intensity and duration of individual pain episodes. The subjective assessment of pain reduction was in the range of 40-47%. Based on our data we recommend tSNS as useful tool in the prophylaxis of primary headaches, including migraine.

Inhibitory effect of high-frequency greater occipital nerve electrical stimulation on trigeminovascular nociceptive processing in rats

Electrical stimulation of the greater occipital nerve (GON) has recently shown promise as an effective non-pharmacological prophylactic therapy for drug-resistant chronic primary headaches, but the neurobiological mechanisms underlying its anticephalgic action are not elucidated. Considering that the spinal trigeminal nucleus (STN) is a key segmental structure playing a prominent role in pathophysiology of headaches, in the present study we evaluated the effects of GON electrical stimulation on ongoing and evoked firing of the dura-sensitive STN neurons. The experiments were carried out on urethane/chloralose-anesthetized, paralyzed and artificially ventilated male Wistar rats. Extracellular recordings were made from 11 neurons within the caudal part of the STN that received convergent input from the ipsilateral facial cutaneous receptive fields, dura mater and GON. In each experiment, five various combinations of the GON stimulation frequency (50, 75, 100 Hz) and intensity (1, 3, 6 V) were tested successively in 10 min interval. At all parameter sets, preconditioning GON stimulation (250 ms train of pulses applied before each recording) produced suppression of both the ongoing activity of the STN neurons and their responses to electrical stimulation of the dura mater. The inhibitory effect depended mostly on the GON stimulation intensity, being maximally pronounced when a stimulus of 6 V was applied. Thus, the GON stimulation-induced inhibition of trigeminovascular nociceptive processing at the level of STN has been demonstrated for the first time. The data obtained can contribute to a deeper understanding of neurophysiological mechanisms underlying the therapeutic efficacy of GON stimulation in primary headaches.

A good preoperative response to transcutaneous electrical nerve stimulation predicts a better therapeutic effect of implanted occipital nerve stimulation in pharmacologically intractable headaches

Occipital nerve stimulation (ONS) is a surgical approach to treat patients with medically intractable chronic headache disorders. However, no preoperative test has been yet validated to allow candidates to be selected for implantation. In this study, the analgesic efficacy of transcutaneous electrical nerve stimulation (TENS) was tested for 1 to 3 months in 41 patients with pharmacologically intractable headache disorders of various origins, using a new technique of electrode placement over the occipital nerve. ONS electrodes were subsequently implanted in 33 patients (occipital neuralgia [n=15], cervicogenic headache [n=7], cluster headache [n=6], chronic migraine [n=5]) who had responded at least moderately to TENS. Assessment was performed up to five years after implantation (three years on average), based on the mean and maximum daily pain intensity scored on a 0-10 visual analogue scale and the number of headache days per month. Both TENS and chronic ONS therapy were found to be efficacious (57-76% improvement compared to baseline on the various clinical variables). The efficacy of ONS was better in cases of good or very good preoperative response to TENS than in cases of moderate response to TENS. Implanted ONS may be a valuable therapeutic option in the long term for patients with pharmacologically intractable chronic headache. Although we cannot conclude in patients with poor or no response to TENS, a good or very good response to TENS can support the indication of ONS therapy. This preoperative test could particularly be useful in patients with chronic migraine, in whom it may be difficult to indicate an invasive technique of cranial neurostimulation.

Transcutaneous supraorbital neurostimulation in "de novo" patients with migraine without aura: the first Italian experience

BACKGROUND

Transcutaneous supraorbital neurostimulation (tSNS) has been recently found superior to sham stimulation for episodic migraine prevention in a randomized trial. We evaluated both the safety and efficacy of a brief period of tSNS in a group of patients with migraine without aura (MwoA).

METHODS

We enrolled 24 consecutive patients with MwoA experiencing a low frequency of attacks, which had never taken migraine preventive drugs in the course of their life. Patients performed a high frequency tSNS and were considered "compliant" if they used the tSNS for ≥ 2/3 of the total time expected. For this reason, four patients were excluded from the final statistical analysis. Primary outcome measures were the reduction migraine attacks and migraine days per month (p < 0.05). Furthermore, we evaluated the percentage of patients having at least 50% reduction of monthly migraine attacks and migraine days. Secondary outcome measures were the reduction of headache severity during migraine attacks and HIT-6 (Headache Impact Test) rating as well as in monthly intake of rescue medication (p < 0.05). Finally, compliance and satisfaction to treatment and potential adverse effects related to tSNS have been evaluated.

RESULTS

Between run-in and second month of tSNS treatment, both primary and secondary endpoints were met. Indeed, we observed a statistically significant decrease in the frequency of migraine attacks (p < 0.001) and migraine days (p < 0.001) per month. We also demonstrated at least 50% reduction of monthly migraine attacks and migraine days in respectively 81 and 75% of patients. Furthermore, a statistically significant reduction in average of pain intensity during migraine attacks (p = 0.002) and HIT-6 rating (p < 0.001) and intake of rescue medication (p < 0.001) has been shown. All patients showed good compliance levels and no relevant adverse events.

CONCLUSION

In patients experiencing a low frequency of attacks, significant improvements in multiple migraine severity parameters were observed following a brief period of high frequency tSNS. Therefore, tSNS may be considered a valid option for the preventive treatment of migraine attacks in patients who cannot or are not willing to take daily medications, or in whom low migraine frequency and/or intensity would not require pharmacological preventive therapies.

The appropriate use of neurostimulation: stimulation of the intracranial and extracranial space and head for chronic pain. Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The International Neuromodulation Society (INS) has identified a need for evaluation and analysis of the practice of neurostimulation of the brain and extracranial nerves of the head to treat chronic pain.

METHODS

The INS board of directors chose an expert panel, the Neuromodulation Appropriateness Consensus Committee (NACC), to evaluate the peer-reviewed literature, current research, and clinical experience and to give guidance for the appropriate use of these methods. The literature searches involved key word searches in PubMed, EMBASE, and Google Scholar dated 1970-2013, which were graded and evaluated by the authors.

RESULTS

The NACC found that evidence supports extracranial stimulation for facial pain, migraine, and scalp pain but is limited for intracranial neuromodulation. High cervical spinal cord stimulation is an evolving option for facial pain. Intracranial neurostimulation may be an excellent option to treat diseases of the nervous system, such as tremor and Parkinson's disease, and in the future, potentially Alzheimer's disease and traumatic brain injury, but current use of intracranial stimulation for pain should be seen as investigational.

CONCLUSIONS

The NACC concludes that extracranial nerve stimulation should be considered in the algorithmic treatment of migraine and other disorders of the head. We should strive to perfect targets outside the cranium when treating pain, if at all possible.

Human vagus nerve branching in the cervical region

BACKGROUND

Vagus nerve stimulation is increasingly applied to treat epilepsy, psychiatric conditions and potentially chronic heart failure. After implanting vagus nerve electrodes to the cervical vagus nerve, side effects such as voice alterations and dyspnea or missing therapeutic effects are observed at different frequencies. Cervical vagus nerve branching might partly be responsible for these effects. However, vagus nerve branching has not yet been described in the context of vagus nerve stimulation.

MATERIALS AND METHODS

Branching of the cervical vagus nerve was investigated macroscopically in 35 body donors (66 cervical sides) in the carotid sheath. After X-ray imaging for determining the vertebral levels of cervical vagus nerve branching, samples were removed to confirm histologically the nerve and to calculate cervical vagus nerve diameters and cross-sections.

RESULTS

Cervical vagus nerve branching was observed in 29% of all cases (26% unilaterally, 3% bilaterally) and proven histologically in all cases. Right-sided branching (22%) was more common than left-sided branching (12%) and occurred on the level of the fourth and fifth vertebra on the left and on the level of the second to fifth vertebra on the right side. Vagus nerves without branching were significantly larger than vagus nerves with branches, concerning their diameters (4.79 mm vs. 3.78 mm) and cross-sections (7.24 mm2 vs. 5.28 mm2).

DISCUSSION

Cervical vagus nerve branching is considerably more frequent than described previously. The side-dependent differences of vagus nerve branching may be linked to the asymmetric effects of the vagus nerve. Cervical vagus nerve branching should be taken into account when identifying main trunk of the vagus nerve for implanting electrodes to minimize potential side effects or lacking therapeutic benefits of vagus nerve stimulation.

Kinetic oscillation stimulation as treatment of acute migraine: a randomized, controlled pilot study

OBJECTIVE

To assess the relief of migraine pain, especially in the acute phase, by comparing active treatment, ie, kinetic oscillation stimulation (KOS) in the nasal cavity, with placebo.

BACKGROUND

Exploratory trials testing the efficacy of KOS on migraine patients indicated that this treatment could be a fast-acting remedy for acute migraine pain.

METHOD

Thirty-six patients were randomized 1:1 using a placebo module to active or placebo treatment in this double-blinded parallel design study. Treatment was administered with a minimally invasive inflatable tip oscillating catheter. Symptom scores (0-10 visual analog scale) were obtained before treatment, every 5 minutes during treatment, at 15 minutes, 2, and 24 hours post-treatment, as well as daily (0-3 migraine pain scale) from 30 days pretreatment until Day 60 post. Thirty-five patients were evaluated (active n=18, placebo n=17). The primary end-point was the change in average pain score from before treatment to 15 minutes after treatment.

RESULTS

Patients who received active treatment reported reduced pain, eg, average visual analog scale pain scores fell from 5.5 before treatment to 1.2 15 minutes after, while the corresponding scores for recipients of placebo fell from 4.9 to 3.9. The changes in pain scores differed between the 2 treatments by 3.3 points (95% confidence interval: 2.3, 4.4), P<.001. Already 5 minutes into the treatment, the difference (1.9 points) was significant (P=.007). The difference was likewise significant at 2 hours post-treatment (3.7 points, P<.001). One patient experienced an adverse event (a vasovagal reaction with full spontaneous recovery) during placebo treatment.

CONCLUSION

KOS is an effective and safe treatment for acute migraine pain.

The influence of ictal cutaneous allodynia on the response to occipital transcutaneous electrical stimulation in chronic migraine and chronic tension-type headache: a randomized, sham-controlled study

OBJECTIVE

The objective of this article is to determine whether cutaneous allodynia (CA) influences the response to treatment with occipital transcutaneous electrical stimulation (OTES) in chronic migraine (CM) and chronic tension-type headache (CTTH).

METHODS

One hundred and sixty consecutive patients with CM or CTTH were randomized to be treated with real or sham OTES stimulation three times a day for two consecutive weeks. All patients completed the validated 12-item allodynia symptom checklist for assessing the presence and the severity of CA during headache attack. Primary end-point was change (≥50%) in number of monthly headache-free days.

RESULTS

There was a significant difference in the percentage of responders in the real OTES compared with sham OTES group (p <0.001). Importantly, there was not a significant change of monthly headache-free days in the allodynic patients with CM and CTTH treated both with real and sham OTES, while the number of headache-free days per month was significantly reduced in the real (86%) but not in the sham group (7%) of non-allodynic patients with CTTH and CM.

CONCLUSIONS

Severe CA is associated with decreased response to treatment with OTES in patients with CM and CTTH.

Dual occipital and supraorbital nerve stimulation for chronic migraine: a single-center experience, review of literature, and surgical considerations

Occipital nerve stimulation (ONS) has been studied in a few clinical trials for the treatment of chronic migraine (CM) with failure to prove sufficient efficacy. To date, peripheral nerve stimulation for the treatment of primary headache is limited to off-label use only. The authors report their institutional experience in CM therapy with combined ONS and supraorbital nerve stimulation (SONS). Fourteen patients treated with dual ONS and SONS for CM were studied with follow-up ranging from 3 to 60 months. Seventy-one percent achieved successful stimulation as defined by a 50% or greater decrease in pain severity. The mean reduction in headache-related visual analog scale (VAS) score was 3.92 ± 2.4. Half of the patients also had resolution of migraine-associated neurological symptoms and returned to normal functional capacity. The main adverse events included lead migration (42.8%), supraorbital lead allodynia (21.4%), and infection (14.2%) with a resulting high reoperation rate (35.7%). The authors' stimulation efficacy was superior to the combined 33% positive response rates (≥ 50% pain reduction) in the published studies of ONS for CM. This is likely due to the fact that topographical paresthesia induced by combined ONS and SONS covers the area of migraine pain better than ONS alone. The authors also discuss effective surgical techniques to prevent patient morbidity.

Nociception specific supraorbital nerve stimulation may prevent cluster headache attacks: serendipity in a blink reflex study

BACKGROUND

In cluster headache, neuromodulation is offered when patients are refractory to pharmacological prophylaxis. Non-invasive peripheral neuromodulatory approaches are of interest. We will focus on these and particularly on nociception specific, transcutaneous supraorbital nerve stimulation.

METHODS

In a study using the nociception specific blink reflex, we made a serendipitous discovery, notably the potential prophylactic effect of bilateral, time contingent, nociception specific, transcutaneous stimulation of the supraorbital nerve.

RESULTS

We report on a case series of seven cluster headache patients, in whom attacks seemed to disappear during repeated stimulation of the supraorbital nerves. Three patients stopped experiencing attacks since study participation.

CONCLUSIONS

Bilateral, time contingent, nociception specific, transcutaneous supraorbital nerve stimulation may have a prophylactic effect in episodic and chronic cluster headache. Given its limited side effects and its non-invasive nature, further studies to investigate this potential peripheral neuromodulatory approach for both episodic and chronic cluster headache are warranted.

Clinical utility of implantable neurostimulation devices in the treatment of chronic migraine

Chronic migraine is a disabling disorder that is costly to individuals and society. Occipital nerve stimulation has been used to treat refractory cases of primary headache disorders including drug-resistant chronic cluster headaches and chronic migraine. The Food and Drug Administration (FDA) off-labeled application of equipment used for peripheral nerve (occipital) stimulation is borrowed from FDA-labeled spinal cord stimulation. Manufacturer-sponsored randomized trials include a feasibility study (ONSTIM-Medtronic) and a safety and efficacy study (St Jude). A non-industry sponsored prospective, randomized crossover study by Serra and Marchiotretto suggests improved quality of life and a significant reduction in medication use. Though preliminary studies suggest occipital nerve stimulation is safe and efficacious in treating chronic migraine headache, complication rates, including lead migration, lead fracture, and surgical site infections remain high. Further studies are needed to demonstrate long-term outcomes, while improved surgical techniques and site-specific equipment are needed to minimize complications.

Peripheral neuromodulation in chronic migraine

Patients with chronic migraines are often refractory to medical treatment. Therefore, they might need other strategies to modulate their pain, according to their level of disability. Neuromodulation can be achieved with several tools: meditation, biofeedback, physical therapy, drugs and electric neurostimulation (ENS). ENS can be applied to the central nervous system (brain and spinal cord), either invasively (cortical or deep brain) or non-invasively [cranial electrotherapy stimulation, transcranial direct current stimulation and transcranial magnetic stimulation]. Among chronic primary headaches, cluster headaches are most often treated either through deep brain stimulation or occipital nerve stimulation because there is a high level of disability related to this condition. ENS, employed through several modalities such as transcutaneous electrical nerve stimulation, interferential currents and pulsed radiofrequency, has been applied to the peripheral nervous system at several sites. We briefly review the indications for the use of peripheral ENS at the site of the occipital nerves for the treatment of chronic migraine.

Drug-resistant cluster headache: long-term evaluation of pain control by posterior hypothalamic deep-brain stimulation

OBJECTIVE

On the basis of recent findings about the pathophysiology of cluster headache and through the experience reported in recent literature, we have reviewed the outcome of four patients affected by drug-resistant cluster headache treated in our department by posterior hypothalamic deep brain stimulation with a follow-up of more than 5 years.

METHODS

Between 2004 and 2006, we selected four patients affected by cluster headache. The diagnosis was based on the International Classification of Headache Disorders II criteria, and all patients were refractory to drug therapy. Under local anesthesia they underwent stereotactic positioning of a stimulation electrode within the posterior hypothalamus, ipsilateral to the site of pain. An intraoperative neurophysiological test stimulation was performed to assess possible side effects and symptoms related to hypothalamic neuronal activity. A second surgery was then performed with the patient under general anesthesia to implant the extension cable and the implantable pulse generator.

RESULTS

After 5 years of follow up, all patients had a valuable benefit with a reduction in episode frequency from 90% to 50% associated with a decrease in pain intensity perception.

CONCLUSION

The long-lasting pain reduction and the improvement in the patients' symptoms should be considered a real positive prospective, not only because there was uncertainty about the persistence of the beneficial effects at a long-term follow-up, but also for the improvement of the quality of life. The stimulation can restore important aspects concerning the psychic condition that very often constitutes an important limiting factor in normal daily life for this type of patient.

Familial and sporadic hemiplegic migraine: diagnosis and treatment

OPINION STATEMENT

Hemiplegic migraine (HM) is a rare subtype of migraine with aura, characterized by transient hemiparesis during attacks. Diagnosis is based on the International Classification of Headache Disorders criteria (ICHD-II). Two types of HM are recognized: familial (FHM) and sporadic hemiplegic migraine (SHM). HM is genetically heterogeneous. Three genes have been identified (CACNA1A, ATP1A2, and SCN1A) but more, so far unknown genes, are involved. Clinically, attacks of the 3 subtypes cannot be distinguished. The diagnosis can be confirmed but not ruled out by genetic testing, because in some HM patients other, not yet identified, genes are involved. The presence of additional symptoms (such as chronic ataxia or epilepsy) may increase the likelihood of identifying a mutation. Additional diagnostics like imaging, CSF analysis, or an EEG are mainly performed to exclude other causes of focal neurological symptoms associated with headache. Conventional cerebral angiography is contraindicated in HM because this may provoke an attack. Because HM is a rare condition, no clinical treatment trials are available in this specific subgroup of migraine patients. Thus, the treatment of HM is based on empirical data, personal experience of the treating neurologist, and involves a trial-and-error strategy. Acetaminophen and NSAIDs often are the first choice in acute treatment. Although controversial in HM, triptans can be prescribed when headaches are not relieved sufficiently with common analgesics. An effective treatment for the severe and often prolonged aura symptoms is more warranted, but currently no such acute treatment is available. Prophylactic treatment can be considered when attack frequency exceeds 2 attacks per month, or when severe attacks pose a great burden that requires reduction of severity and frequency. In no strictly preferred order, flunarizine, sodium valproate, lamotrigine, verapamil, and acetazolamide can be tried. While less evidence is available for prophylactic treatment with topiramate, candesartan, and pizotifen, these drugs can also be considered. The use of propranolol in HM is more controversial, but evidence of adverse effects is insufficient to contraindicate beta-blockers.

Long-term improvement in refractory headache following ozone therapy

BACKGROUND

Headache afflicts approximately 10%-15% of the general population. Mixed results are obtained from various therapies, usually drugs, but also oxygen inhalation, behavioral psychology, physical therapy, and peripheral or central neurostimulation. When refractory to treatment, it has severe impact on quality of life. OBJECTIVES/SUBJECTS: Five (5) patients are presented who had suffered from severe/persistent headache refractory to standard management (including 5-HT1 agonist triptan drugs) and were treated with ozone therapy.

INTERVENTIONS

Ozone administration was by major autohemotherapy. The procedure involved venous blood drawn into a sterile single-use glass bottle containing anticoagulant, gently mixed with an equal volume of O3/O2 gas mixture (prefiltered through a sterile 0.20-μm filter) and slowly reinfused back into the donor patient via the antecubital vein.

OUTCOME MEASURES

The analyzed parameters were analgesia requirements, days of sick leave due to headache, number of headache events, and pain intensity according to the visual analogue scale (VAS); these recorded at three time points: pre-ozone therapy, post-ozone therapy, and before the last follow-up (mean: 64.6±36.8 months).

RESULTS

The number of headache episodes pretreatment (n=80; range 5-200) was significantly decreased during the first 6 months post-treatment (n=0, range 0-1; p=0.042) and over the 6 months before the last follow-up visit (n=1, range 0-2; p=0.043). The corresponding VAS scores were 8.7±0.8 pretreatment versus 1.1±2.5 the 6 months post-treatment (p=0.003) and versus 3.1±3.3 the 6 months before last follow-up visit (p=0.036).

CONCLUSIONS

Ozone therapy decreased headache episodes and pain severity over a protracted period. This novel approach is effective and merits further research.

[Application of acupuncture as a headache management tool]

We use two oriental medical techniques in headache management. One is topological microstimulation, and the other is acupuncture point BL10 (Tianzhu) block. 1. Topological microstimulation The topological microstimulation apparatus delivers programmed fluctuating electrical signals to electrodes placed on the distal portion of the limbs, where meridians are concentrated. Topological microstimulation adjusts "qi-blood-fluid" circulating through meridians. "Qi-blood-fluid" is a virtual concept of oriental medicine that means 3 elements (qi, blood, and colorless body fluid). Topological microstimulation induces natural healing power through the bio-homeostatic function, and reduces chronic intractable pain. 2. Acupuncture point BL10 (Tianzhu) block Tianzhu as a meridian point is located at the intersection of the superior nuchal line of the occipital bone and lateral border of the trapezius. This site is located in the superficial layer of the trunk of the greater occipital nerve. Tianzhu block has therapeutic effects on the trigeminocervical complex. As a result, various types of headache are relieved. Tianzhu block was performed in 50 patients in our clinic, and marked effects were observed in 6 patients, moderate effects in 22, slight effects in 19, and no effects in 3. According to the type of headache, this block was effective in 47% of patients with tension-type headache, 38% of those with migraine, 50% of those with chronic daily headache, and 71% of those with neck and/or shoulder pain. Conclusion Various somatic and mental stresses induce headache and functional somatic syndrome, i.e., Tianzhu syndrome. Acupuncture is useful and can be actively recommended for the management of intractable headache such as complicated headache due to Tianzhu syndrome.

Advanced interventions for headache

Many headache patients present when medications fail, are inadequate, are contraindicated, or are not tolerated. These are patients with severe disability. Most have daily headaches, including chronic migraine, trigeminal autonomic cephalalgias, or other primary headaches. This brief review addresses, in broad strokes, some thoughts about alternatives beyond the usual daily oral preventive therapies. Do not proceed to more invasive or elaborate approaches until the big 3 are done: diagnosis is established, onabotulinumtoxinA administered when appropriate, that is, if the patient has chronic migraine, and wean is accomplished if the patient has medication overuse headache. Large numbers of patients are helped without the need for more arcane and unproven treatments by following these initial approaches. Simple nerve blocks can be useful in the initial steps, but more invasive blocks and stimulators are not recommended until the big 3 are completed. Wean of overused medications must be absolute and may require an intravenous bridge over several days, either in an infusion unit or inpatient in a medical model. Wean should be accompanied by establishing onabotulinumtoxinA or daily prevention from the beginning. Consider referral to a structured multidisciplinary headache program. This is for patients who require an interdisciplinary approach and may be day-hospital or inpatient. Invasive blocks and stimulators may be appropriate, and the latter are currently being studied in controlled studies. The most promise, with the best balance of efficacy vs adverse event prospects, may be occipital nerve stimulators or sphenopalatine ganglion stimulators.

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.