High-Cervical Spinal Cord Stimulation for Medically Intractable Chronic Migraine

Resistant and refractory migraine: clinical presentation, pathophysiology, and management

Migraine is a leading cause of disability worldwide. A minority of individuals with migraine develop resistant or refractory conditions characterised by ≥ 8 monthly days of debilitating headaches and inadequate response, intolerance, or contraindication to ≥3 or all preventive drug classes, respectively. Resistant and refractory migraine are emerging clinical definitions stemming from better knowledge of the pathophysiology of migraine and from the advent of migraine-specific preventive treatments. Resistant migraine mostly results from drug failures, while refractory migraine has complex and still unknown mechanisms that impair the efficacy of preventive treatments. Individuals with resistant migraine can be treated with migraine-specific preventive drugs. The management of refractory migraine is challenging and often unsuccessful, being based on combinations of different drugs and non-pharmacological treatment. Future research should aim to identify individuals at risk of developing treatment failures, prevent the condition, investigate the mechanisms of refractoriness to treatments, and find effective treatment strategies.

Use of spinal cord stimulation in treatment of intractable headache diseases

Headache diseases remain one of the leading causes of disability in the world. With the development of neuromodulation strategies, high cervical spinal cord stimulation (hcSCS) targeting the trigeminocervical complex has been deployed to treat refractory headache diseases. In this article, we review the proposed mechanism behind hcSCS stimulation, and the various studies that have been described for the successful use of this treatment strategy in patients with chronic migraine, cluster headache, and other trigeminal autonomic cephalalgias.

Cervical Spinal Cord Stimulation for the Treatment of Headache Disorders: A Systematic Review

OBJECTIVES

Chronic headache remains a major cause of disability and pain worldwide. Although the literature has extensively described pharmacologic options for headache treatment and prophylaxis, there remains a paucity of data on the efficacy of neuromodulation interventions for treatment of headache unresponsive to conventional pharmacologic therapy. The primary aim of this review was to appraise the literature for the efficacy of cervical spinal cord stimulation (cSCS) in treating any intractable chronic headache, including migraine headaches (with or without aura), cluster headache, tension headache, and other types of headaches.

MATERIALS AND METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we performed a systematic review by identifying studies in PubMed, Embase (Scopus), Web of Science, and Cochrane Central Register of Controlled Trials that assessed cSCS to treat chronic headache. Data were synthesized qualitatively, with primary outcomes of headache intensity and frequency. The secondary outcome was adverse effects.

RESULTS

In total, 16 studies comprising 107 patients met the inclusion criteria. Findings were presented based on type of headache, which included migraine headache with or without aura, cluster headache, trigeminal neuropathy, occipital neuralgia, posttraumatic headache, cervicogenic headache, short-lasting unilateral neuralgiform headache with autonomic symptoms, and poststroke facial pain. Per the Grading of Recommendations, Assessment, Development and Evaluations criteria, there was very low-quality evidence that cSCS is associated with a decrease in migraine headache frequency, migraine headache intensity, and trigeminal neuropathy intensity. Placement for cSCS leads ranged from C1 to C4.

CONCLUSIONS

Our review suggests promising data from observational studies that cSCS may be helpful in decreasing frequency and intensity of chronic intractable headache. Future well-powered, randomized controlled trials are needed.

Migraine: Advances in the Pathogenesis and Treatment

This article presents a comprehensive review on migraine, a prevalent neurological disorder characterized by chronic headaches, by focusing on their pathogenesis and treatment advances. By examining molecular markers and leveraging imaging techniques, the research identifies key mechanisms and triggers in migraine pathology, thereby improving our understanding of its pathophysiology. Special emphasis is given to the role of calcitonin gene-related peptide (CGRP) in migraine development. CGRP not only contributes to symptoms but also represents a promising therapeutic target, with inhibitors showing effectiveness in migraine management. The article further explores traditional medical treatments, scrutinizing the mechanisms, benefits, and limitations of commonly prescribed medications. This provides a segue into an analysis of emerging therapeutic strategies and their potential to enhance migraine management. Finally, the paper delves into neuromodulation as an innovative treatment modality. Clinical studies indicating its effectiveness in migraine management are reviewed, and the advantages and limitations of this technique are discussed. In summary, the article aims to enhance the understanding of migraine pathogenesis and present novel therapeutic possibilities that could revolutionize patient care.

A narrative review and future considerations of spinal cord stimulation, dorsal root ganglion stimulation and peripheral nerve stimulation

PURPOSE OF REVIEW

In recent years, neuromodulation has experienced a renaissance. Novel waveforms and anatomic targets show potential improvements in therapy that may signify substantial benefits. New innovations in peripheral nerve stimulation and dorsal root ganglion stimulation have shown prospective evidence and sustainability of results. Sub-perception physiologic bursting, high-frequency stimulation and feedback loop mechanisms provide significant benefits over traditional tonic spinal cords stimulation (SCS) in peer reviewed investigations. We reviewed the themes associated with novel technology in the context of historical stalwart publications.

RECENT FINDINGS

New innovations have led to better nerve targeting, improvements in disease-based treatment, and opioid alternatives for those in chronic pain. In addition, new neural targets from both structural and cellular perspectives have changed the field of Neurostimulation.

SUMMARY

For many years, tonic SCS was representative of neuromodulation, but as this review examines, the progression of the field in the past decade has reshaped patient options.

Update of Neuromodulation in Chronic Migraine

Purpose of Review

Neuromodulation devices have become an attractive alternative to traditional pharmacotherapy for migraine, especially for patients intolerant to medication or who prefer non-pharmacological options. In the past decades, many studies demonstrated the efficacy of neuromodulation devices in patients with episodic migraine (EM). However, the benefit of these devices on chronic migraine (CM), which is typically more debilitating and refractory than EM, remains not well studied.

Recent Findings

We reviewed the literature within the last five years on using FDA-cleared and investigational devices for CM. There were eight randomized controlled trials and 15 open-label observational studies on ten neuromodulation devices.

Summary

Neuromodulation is promising for use in CM, although efficacy varies among devices or individuals. Noninvasive devices are usually considered safe with minimal adverse events. However, stimulation protocol and methodology differ between studies. More well-designed studies adhering to the guideline may facilitate FDA clearance and better insurance coverage.

Safety and Efficacy of 10 kHz Spinal Cord Stimulation for the Treatment of Refractory Chronic Migraine: A Prospective Long-Term Open-Label Study

BACKGROUND

Refractory chronic migraine (rCM) is a highly disabling condition for which novel safe and effective treatments are needed. Safety and long-term efficacy of paresthesia-free high cervical 10 kHz spinal cord stimulation (SCS) were here prospectively evaluated for the treatment of rCM.

MATERIALS AND METHODS

Twenty adults with rCM (mean numbers of preventive treatments failed: 12.2 ± 3.1) were enrolled in this single-center, open-label, prospective study and implanted with a 10 kHz SCS system (Senza™ system, Nevro Corp.), with the distal tip of the lead(s) positioned epidurally at the C2 vertebral level. Safety and effectiveness outcomes, such as adverse events, headache and migraine reductions, responder rates, Migraine Disability Assessment (MIDAS), Headache Impact Test-6 (HIT-6), and Migraine-Specific Quality-of-Life (MSQ), were captured up to 52 weeks after implantation.

RESULTS

Compared to baseline, at 52 weeks postimplantation, there was a significant reduction of mean monthly migraine days (MMD) by 9.3 days (p < 0.001). Sixty percent and 50% of patients obtained respectively at least 30% and at least 50% reduction in mean MMD. By week 52, 50% of patients' chronic pattern converted to an episodic pattern. The proportion of subjects classified with severe headache-related disability on the HIT-6, decreased from 100% to 60% at week 52. Meaningful improvements of headache-related quality of life measured by the MSQ scale were observed with mean gain of 24.9 ± 23.1 (p < 0.001) points at 52 weeks. No unanticipated adverse device effects occurred. No patients required any additional device surgical revision.

CONCLUSION

10 kHz SCS may a be safe and effective neurostimulation option for rCM patients. The paresthesia-free waveform constitutes an unprecedented advantage for future methodologically sound sham-controlled studies in headache neuromodulation.

Trends in Clinical Trials for Spinal Cord Stimulation

BACKGROUND

Spinal cord stimulation (SCS) is a neuromodulation technology widely used in the treatment of intractable chronic pain syndromes. SCS is now being applied more broadly as a possible therapy for a range of indications, including neurological, cardiac, and gastrointestinal disorders. Ongoing research in this field is critical in order to gain further insights into the mechanisms of SCS, determine its role in new indications, and refine programming techniques for the optimization of therapeutic outcomes.

OBJECTIVE

To assess the state of SCS-related human research by cataloging and summarizing clinical trials that have been recently completed or are currently underway in this field.

METHODS

A search was conducted for clinical trials pertaining to SCS using the ClinicalTrials.gov database. Trials were analyzed to generate a detailed overview of ongoing SCS-related research. Specifically, trials were categorized by intervention, trial start date, study completion status, clinical phase, projected subject enrollment, condition, country of origin, device manufacturer, funding source, and study topic.

RESULTS

In total, 212 relevant clinical trials were identified. 175 trials (82.5%) involved invasive SCS, while the remaining 37 trials (17.5%) used noninvasive forms of spinal stimulation. Most trials examined the efficacy of SCS for chronic pain syndromes or new indications, while others assessed different stimulation parameters. The studies spanned >27 different disorders, with almost 20% of trials pertaining to conditions other than chronic pain syndromes. The majority of SCS trials were US-based (55.7% of studies), but many countries (e.g., Belgium and UK) are becoming increasingly active. The ratio of investigator-sponsored to industry-sponsored trials was 2:1. Emphasizing the need to optimize therapeutic outcomes of SCS, one-quarter of trials predominantly focused on the assessment of alternative stimulation parameters such as burst or high-frequency stimulation.

CONCLUSIONS

A large number of clinical trials of SCS are underway. Improvements in the treatment of pain and novel indications for SCS constitute the majority of studies. This overview of SCS-related clinical trials provides a window into future new indications, novel stimulation techniques, and a heightened understanding of the mechanisms of action.

Neuromodulation in headache and craniofacial neuralgia: guidelines from the Spanish Society of Neurology and the Spanish Society of Neurosurgery

INTRODUCTION

Numerous invasive and non-invasive neuromodulation devices have been developed and applied to patients with headache and neuralgia in recent years. However, no updated review addresses their safety and efficacy, and no healthcare institution has issued specific recommendations on their use for these 2 conditions.

METHODS

Neurologists from the Spanish Society of Neurology's (SEN) Headache Study Group and neurosurgeons specialising in functional neurosurgery, selected by the Spanish Society of Neurosurgery (SENEC), performed a comprehensive review of articles on the MEDLINE database addressing the use of the technique in patients with headache and neuralgia.

RESULTS

We present an updated review and establish the first set of consensus recommendations of the SEN and SENC on the use of neuromodulation to treat headache and neuralgia, analysing the current levels of evidence on its effectiveness for each specific condition.

CONCLUSIONS

Current evidence supports the indication of neuromodulation techniques for patients with refractory headache and neuralgia (especially migraine, cluster headache, and trigeminal neuralgia) selected by neurologists and headache specialists, after pharmacological treatment options are exhausted. Furthermore, we recommend that invasive neuromodulation be debated by multidisciplinary committees, and that the procedure be performed by teams of neurosurgeons specialising in functional neurosurgery, with acceptable rates of morbidity and mortality.

Cervical Spinal Cord Stimulation Using Monophasic Burst Waveform for Axial Neck and Upper Extremity Radicular Pain: A Preliminary Observational Study

BACKGROUND

Cervical spinal cord stimulation (cSCS) is an accepted therapeutic option for radicular upper extremity pain and less commonly for cervical axial pain despite less available literature in comparison with lumbar and lower extremity applications.

METHODS

This preliminary observational pilot study evaluated the efficacy of cSCS using the monophasic burst pattern in the treatment of both upper extremity radicular pain and axial neck pain. Primary outcome measures were reduction in pain scores, global pain scale (GPS) indices, and neck Oswestry disability index (nODI).

RESULTS

Of the 23 subjects trialed, 15 went to implantation of cSCS using burst and were followed for 1 year prospectively. Pre- and postprimary outcome measures suggested a statistically (p < 0.05) and clinically significant 12.40 point differential in the nODI, a statistically significant reduction of the GPS from 74.60 to 56.37 (p < 0.05), and a reduction in the pain rating score from 8.13 +/- 1.0 prior to trial to 3.85 +/- 1.1 at 1 year for axial neck and with and without radicular pain (p < 0.05).

CONCLUSIONS

This preliminary study suggests that the use of the burst waveform applied to cSCS results in improved function and decreased pain scores in subjects with axial neck pain with and without radicular symptomatology and cervicogenic headache.

New strategies for the treatment and prevention of primary headache disorders

The primary headache disorders, which include migraine, cluster headache and tension-type headache, are among the most common diseases and leading causes of disability worldwide. The available treatment options for primary headache disorders have unsatisfactory rates of efficacy, tolerability and patient adherence. In this Review, we discuss promising new approaches for the prevention of primary headache disorders, such as monoclonal antibodies targeting calcitonin gene-related peptide (CGRP) or its receptor, and small-molecule CGRP receptor antagonists. Neuromodulation approaches employing noninvasive or implantable devices also show promise for treating primary headache disorders. Noninvasive treatments, such as transcranial magnetic stimulation and transcutaneous peripheral nerve stimulation, are delivered by devices that patients can self-administer. Implantable devices targeting the occipital nerves, sphenopalatine ganglion or high cervical spinal cord are placed using percutaneous and/or surgical procedures, and are powered either wirelessly or by surgically implanted batteries. These new and emerging treatments have the potential to address unmet patient needs and reduce headache-associated disability.

Non-Pharmacological Approaches for Migraine

Migraine is one of the most common and debilitating neurological disorders. However, the efficacy of pharmacological therapies may have unsatisfactory efficacy and can be poorly tolerated. There is a strong need in clinical practice for alternative approaches for both acute and preventive treatment. Occasionally, this need might arise in the context of low-frequency migraneurs who are not keen to use medication or fear the potential side effects. At the opposite end of the spectrum, clinicians might be faced with patients who have proven refractory to numerous medications. These patients may benefit from invasive treatment strategies. In recent years, promising strategies for migraine therapy have emerged alongside a progressively better understanding of the complex pathophysiology underlying this disease. This review discusses the most recent and evidence-based advances in non-pharmacological therapeutic approaches for migraine, offering alternatives to drug treatment for both the commonly encountered episodic cases as well as the more complex migraine phenotypes, which are capable of challenging even the headache specialist.

Peripheral Nerve Stimulation for Painful Mononeuropathy Secondary to Leprosy: A 12-Month Follow-Up Study

OBJECTIVE

Leprosy affects approximately 10-15 million patients worldwide and remains a relevant public health issue. Chronic pain secondary to leprosy is a primary cause of morbidity, and its treatment remains a challenge. We evaluated the feasibility and safety of peripheral nerve stimulation (PNS) for painful mononeuropathy secondary to leprosy that is refractory to pharmacological therapy and surgical intervention (decompression).

METHODS

Between 2011 and 2013 twenty-three patients with painful mononeuropathy secondary to leprosy were recruited to this prospective case series. All patients were considered to be refractory to optimized conservative treatment and neurosurgical decompression. Pain was evaluated over the course of the study using the neuropathic pain scale and the visual analog scale for pain. In the first stage, patients were implanted with a temporary electrode that was connected to an external stimulator, and were treated with PNS for seven days. Patients with 50% or greater pain relief received a definitive implantation in the second stage. Follow-ups in the second stage were conducted at 1, 3, 6, and 12 months.

RESULTS

After seven days of trial in the first stage, 10 patients showed a pain reduction of 50% or greater. At 12-month follow-up in the second stage, 6 of the 10 patients who underwent permanent device implantation showed a pain reduction of 50% or greater (75% reduction on average), and two patients showed a 30% reduction in pain. Two patients presented with electrode migration that required repositioning during the 12-month follow-up period.

CONCLUSIONS

Our data suggest that PNS might have significant long-term utility for the treatment of painful mononeuropathy secondary to leprosy. Future studies should be performed in order to corroborate our findings in a larger population and encourage the clinical implementation of this technique.

Alternate Intraspinal Targets for Spinal Cord Stimulation: A Systematic Review

BACKGROUND

Conventional dorsal column spinal cord stimulation (SCS) provides less than optimal pain relief for certain pain syndromes and anatomic pain distributions. Practitioners have sought to treat these challenging therapeutic areas with stimulation of alternate intraspinal targets.

OBJECTIVE

To identify and systematically review the evidence for the value neuromodulating specific neuronal targets within the spinal canal to achieve relief of chronic pain.

METHODS

A systematic literature search was conducted using PubMed for clinical trials published from 1966 to March 1, 2015 to identify neurostimulation studies that employed non-dorsal column intraspinal stimulation to achieve pain relief. Identified studies on such targeted intraspinal stimulation were reviewed and graded using Evidence Based Interventional Pain Medicine criteria.

RESULTS

We found a total of 13 articles that satisfied our search criteria on targeted, non-dorsal column intraspinal stimulation for pain. We identified five studies on neurostimulation of the cervicomedullary junction, six studies on neurostimulation of the dorsal root ganglion, two studies on the neurostimulation of the conus medullaris, unfortunately none was found on intraspinal nerve root stimulation.

LIMITATIONS

The limitations of this review include the relative paucity of well-designed prospective studies on targeted SCS.

CONCLUSIONS

Clinical use of intraspinal neurostimulation is expanding at a very fast pace. Intraspinal stimulation of non-dorsal column targets may well be the future of neurostimulation as it provides new clinically significant neuromodulation of specific therapeutic targets that are not well or not easily addressed with conventional dorsal column SCS. In addition, they may avoid undesired stimulation induced paraesthesia, particularly in non-painful areas of the body.

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.