Peripheral neurostimulation in primary headaches

Cluster headache

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

Neurostimulation for Refractory Cervicogenic Headache: A Three-Year Retrospective Study

BACKGROUND

Occipital nerve stimulation (ONS) has been used for the treatment of neuropathic pain conditions and could be a therapeutic approach for refractory cervicogenic headache (CeH).

AIM

The aim of this study is to assess the efficacy and safety of unilateral ONS in patients suffering from refractory CeH.

METHODS

We conducted a retrospective chart review on patients implanted from 2011 to 2013 at CHUM. The primary outcome was a 50% reduction in headache days per month. Secondary outcomes included change in EuroQol Group Visual Analog Scale rating of health-related quality of life (EQ VAS), six item headache impact test (HIT-6) score, hospital anxiety and depression scale (HADS) score, work status, and medication overuse.

RESULTS

Sixteen patients fulfilled the inclusion criteria; they had suffered from daily moderate to severe CeH for a median of 15 years. At one year follow-up, 11 patients were responders (69%). There was a statistically significant improvement in the EQ VAS score (median change: 40 point increase, p = 0.0013) and HIT-6 score (median change: 17.5 point decrease, p = 0.0005). Clinically significant anxiety and depression scores both resolved amongst 60% of patients. At three years, six patients were responders (37.5%). Out of the 11 responders at one-year post implantation, five had remained headache responders (R-R) and one additional patient became a responder (NR-R). There was a statistically significant improvement in the EQ VAS score (median change: 15 point increase, p = 0.019) and HIT-6 score (median change: 7.5 point decrease, p = 0.0017) compared with baseline. Clinically significant anxiety and depression scores both, respectively, resolved among 22.5% and 33.9% of patients. Five out of seven disabled patients were back to work.

CONCLUSION

ONS may be a safe and effective treatment modality for patients suffering from a refractory CeH. Further study may be warranted.

External Trigeminal Nerve Stimulation for the Acute Treatment of Migraine: Open-Label Trial on Safety and Efficacy

OBJECTIVE

The aim of the current study is to assess the safety and efficacy of external trigeminal nerve stimulation (e-TNS) via a transcutaneous supraorbital stimulator as an acute treatment for migraine attacks.

MATERIALS AND METHODS

This was a prospective, open-labeled clinical trial conducted at the Columbia University Headache Center (NY, USA). Thirty patients who were experiencing an acute migraine attack with or without aura were treated with a one-hour session of e-TNS (CEFALY Technology) at the clinic. Pain intensity was scored using a visual analogue scale (VAS) before the treatment, after the one-hour treatment session, and at two hours after treatment initiation. Rescue migraine medication intake was recorded at 2 and 24 hours.

RESULTS

Thirty patients were included in the intention-to-treat analysis. Mean pain intensity was significantly reduced by 57.1% after the one-hour e-TNS treatment (-3.22 ± 2.40; p < 0.001) and by 52.8% at two hours (-2.98 ± 2.31; p < 0.001). No patients took rescue medication within the two-hour observation phase. Within the 24-hour follow-up, 34.6% of patients used a rescue medication. No adverse events or subjective complaints were reported.

CONCLUSIONS

The findings from this open-labeled study suggest that transcutaneous supraorbital neurostimulation may be a safe and effective acute treatment for migraine attacks, and merits further study with a double-blind, randomized, sham-controlled trial.

Central and Peripheral Neural Targets for Neurostimulation of Chronic Headaches

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

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.

Cluster headache and other TACs: Pathophysiology and neurostimulation options

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Safety and efficacy of cervical 10 kHz spinal cord stimulation in chronic refractory primary headaches: a retrospective case series

Background

Paresthesia-free cervical 10 kHz spinal cord stimulation (HF10 SCS) may constitute a novel treatment modality for headache disorders, when pharmacological approaches fail. We report the results of a retrospective analysis assessing the long-term safety, tolerability and efficacy of HF10 SCS in a group of patients with chronic refractory primary headache disorders.

Findings

Four patients with chronic migraine (CM), two with chronic SUNA (Short-lasting Unilateral Neuralgiform headache attacks with Autonomic symptoms) and one with chronic cluster headache (CCH) refractory to medical treatments, were implanted with cervical HF10 SCS. Pre- and post-implantation data were collected from the medical notes and from headache charts. At an average follow-up of 28 months (range: 12–42 months) we observed an improvement of at least 50 % in headache frequency and/or intensity in all CM patients. One SUNA patient became pain free and the other reported at least 50 % improvement in attacks frequency an duration. The CCH patient reported a significant reduction in CH attacks duration. Two patients underwent a surgical revision due to lead migration.

Conclusions

Paresthesia-free high cervical HF10 SCS appears to be a long-term safe and likely effective therapeutic approach for patients with chronic refractory primary headache disorders. These results warrant further prospective studies in larger series of patients.

Neurostimulation in the treatment of primary headaches

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

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 Nerve Stimulation (t-SNS) with the Cefaly® Device for Migraine Prevention: A Review of the Available Data

So far, among the different non-invasive neurostimulation methods, only transcutaneous supraorbital nerve stimulation (t-SNS) with the Cefaly® (Cefaly Technology sprl, Herstal, Belgium) device has randomized controlled trial-based evidence for safety and efficacy and obtained American Food and Drug Administration approval for the prevention of episodic migraine. In a double-blinded, randomized, sham-controlled trial on 67 episodic migraine patients (mean pre-treatment migraine days/month: 6.9), the 50% responder rate after 3 months was significantly higher in the active group (38.2%) than in the sham group (12.1%); attack frequency and total headache days were also significantly reduced, but not headache severity. Acute anti-migraine drug intake was reduced by 36.7% in the active group. Statistical sub-analysis suggested that t-SNS was more effective in patients with a higher attack frequency. In a large survey on 2313 Cefaly users about safety and satisfaction only 4.3% of subjects reported side effects, all of which were minor and fully reversible, the most frequent being intolerance to the paresthesia feeling and the most severe an allergic skin reaction to the electrode gel. The efficacy/safety ratio of the Cefaly device was therefore most favorable, especially when compared to preventive anti-migraine drugs. The therapeutic efficacy of t-SNS with Cefaly with low-frequency migraine (≤5 attacks/month) was recently confirmed in an open randomized trial. No published data are available in chronic migraine. According to preliminary results of a fluorodeoxyglucose-positron emission tomography study, Cefaly might exert its effect in migraine by increasing activity in crucial areas of the limbic system and salience matrix such as orbitofrontal and anterior cingulate cortices.