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

Four Decades of Occipital Nerve Stimulation for Headache Disorders: A Systematic Review

PURPOSE OF REVIEW

Chronic headaches are a significant source of disability worldwide. Despite the development of conventional strategies, a subset of patients remain refractory and/or experience side effects following these treatments. Hence, occipital nerve stimulation (ONS) should be considered as an alternative strategy for intractable chronic headaches. This review aims to provide a comprehensive overview of the effectiveness, safety, mechanisms and practical application of ONS for the treatment of headache disorders.

RECENT FINDINGS

Overall response rate of ONS is 35.7-100%, 17-100%, and 63-100% in patients with cluster headache, chronic migraine and occipital neuralgia respectively. Regarding the long-term effectivity in all groups, 41.6-88.0% of patients remain responders after ≥ 18.3 months. The most frequently reported adverse events include lead migration/fracture (13%) and local pain (7.3%). Based on our results, ONS can be considered a safe and effective treatment for chronic intractable headache disorders. To support more widespread application of ONS, additional research with larger sample sizes should be conducted.

Efficacy of Occipital Nerve Stimulation in Trigeminal Autonomic Cephalalgias: A Systematic Review

BACKGROUND

Trigeminal autonomic cephalalgias (TACs) are a group of highly disabling primary headache disorders. Although pharmacological treatments exist, they are not always effective or well tolerated. Occipital nerve stimulation (ONS) is a potentially effective surgical treatment.

OBJECTIVE

To perform a systematic review of the efficacy of ONS in treating TACs.

METHODS

A systematic review was performed using Medline, Embase, and Cochrane databases. Primary outcomes were reduction in headache intensity, duration, and frequency. Secondary outcomes included adverse event rate and reduction in medication use. Because of large differences in outcome measures, data for patients suffering from short-lasting, unilateral, and neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and cranial autonomic symptoms (SUNA) were reported separately. Risk of bias was assessed using the NIH Quality Assessment Tools.

RESULTS

A total of 417 patients from 14 published papers were included in the analysis, of which 15 patients were in the SUNCT/SUNA cohort. The mean reduction in headache intensity and duration was 26.2% and 31.4%, respectively. There was a mean reduction in headache frequency of 50%, as well as a 61.2% reduction in the use of abortive medications and a 31.1% reduction in the use of prophylactic medications. In the SUNCT/SUNA cohort, the mean decrease in headache intensity and duration was 56.8% and 42.8%. The overall responder rate, defined as a >50% reduction in attack frequency, was 60.8% for the non-SUNCT/non-SUNA cohort and 66.7% for the SUNCT/SUNA cohort. Adverse events requiring repeat surgery were reported in 33% of cases. Risk of bias assessment suggests that articles included in this review had reasonable internal validity.

CONCLUSION

ONS may be an effective surgical treatment for approximately two thirds of patients with medically refractory TACs.

Long term outcomes of occipital nerve stimulation

Background

Occipital nerve stimulation (ONS) has been investigated as a potential treatment for disabling headaches and has shown promise for disorders such as chronic migraine and cluster headache. Long term outcomes stratified by headache subtype have had limited exploration, and literature on outcomes of this neuromodulatory intervention spanning 2 or more years is scarce.

Measures

We performed a narrative review on long term outcomes with ONS for treatment of headache disorders. We surveyed the available literature for studies that have outcomes for 24 months or greater to see if there is a habituation in response over time. Review of the literature revealed evidence in treatment of occipital neuralgia, chronic migraine, cluster headache, cervicogenic headache, short lasting unilateral neuralgiform headache attacks (SUNHA) and paroxysmal hemicrania. While the term "response" varied per individual study, a total of 17 studies showed outcomes in ONS with long term sustained responses (as defined per this review) in the majority of patients with specific headache types 177/311 (56%). Only 7 studies in total (3 cluster, 1 occipital neuralgia, 1 cervicogenic headache, 1 SUNHA, 1 paroxysmal hemicrania) provided both short-term and long-term responses up to 24 months to ONS. In cluster headache, the majority of patients (64%) were long term responders (as defined per this review) and only a minority of patients 12/62 (19%) had loss of efficacy (e.g., habituation). There was a high number 313/439 (71%) of adverse events per total number of patients in the studies including lead migration, requirements of revision surgery, allergy to surgical materials, infection and intolerable paresthesias.

Conclusions

With the evidence available, the response to ONS was sustained in the majority of patients with cluster headache with low rates of loss of efficacy in this patient population. There was a high percent of adverse events per number of patients in long term follow-up and likely related to the off-label use of leads typically used for spinal cord stimulation. Further longitudinal assessments of outcomes in occipital nerve stimulation with devices labelled for use in peripheral nerve stimulation are needed to evaluate the extent of habituation to treatment in headache.

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.

Long-Term Experience with Occipital and Supraorbital Nerve Stimulation for the Various Headache Disorders-A Retrospective Institutional Case Series of 96 Patients

OBJECTIVE

We have provided long-term data on clinically meaningful pain alleviation for drug-refractory headache disorders using occipital (ONS) and supraorbital nerve stimulation (SONS).

METHODS

We performed a retrospective review of 96 patients with migraine, cervicogenic headache, cluster headache, neuropathic pain of the scalp, tension-type headache, and new daily persistent headache who had undergone ONS (61.5%), SONS (11.5%), or combined ONS plus SONS (27.1%) trial implantation and definitive implantation from 2007 to 2017. Changes in pain perception over time were monitored using the visual analog scale (VAS) for pain.

RESULTS

The cohort consisted of 60.4% women and 39.6% men, with a mean age of 46.9 ± 11.5 years and pain duration of 14 ± 14.1 years. Of the 96 patients, 65 (67.7%) were treatment responders to a trial (≥30% amelioration in the average or maximum VAS score for pain and/or number of headache days) that had lasted 22.5 ± 8.8 days. The reduction in their average VAS score for pain was to 37% ± 24.4% of baseline compared with 99.1% ± 24.1% of baseline for those without a response (P < 0.01). Of the 56 patients who had undergone implantation and had long-term follow-up data available for ≤10 years, 32 (57.1%) reported a ≥50% reduction in their average VAS score for pain. Four patients (6.5%) had requested hardware explantation. Stage II complications included 1 infection (1.6%) and 6 electrode dislocations (9.7%). The study limitations included the retrospective nature, lack of controls receiving placebo intervention, and randomization.

CONCLUSIONS

After careful patient selection according to a positive response to a trial of ONS and/or SONS, clinically meaningful long-term benefit was achieved in 57.1% of our patients with various chronic headache conditions.

Peripheral nerve stimulation registry for intractable migraine headache (RELIEF): a real-life perspective on the utility of occipital nerve stimulation for chronic migraine

BACKGROUND

Migraine is common and ranked as the first cause of disability in people under fifty. Despite significant advances in its pharmacological treatment, it often remains intractable. Neuromodulation is one option considered in the management of those patients.

OBJECTIVE

To assess the safety and efficacy of neuromodulation in the treatment of intractable chronic migraine using the Abbott occipital nerve stimulator.

METHODS

Recruitment took place in 18 centres in 6 countries. Patients over the age of 18 who had failed three or more preventative drugs, had at least moderate disability based on MIDAS or HIT-6 score and were implanted with an Abbott neurostimulator were included in the study. Patients were followed up for a maximum of 24 months. Data were collected on adverse events, headache relief, headache days, quality of life, migraine disability, satisfaction and quality of life.

RESULTS

One hundred twelve patients were included, 79 female and 33 male, with 45 patients reaching the maximum follow-up of 24 months. At 3 months, 33.7% were satisfied or very satisfied with the procedure with 43.0% reporting improved or greatly improved quality of life. 67.5% indicated that they would undergo the procedure again with satisfaction peaking at 9 months when 49.3% were satisfied or very satisfied with the procedure. At 24 months, 46.7% of available patients were satisfied or very satisfied with the procedure-18% of enrolled patients. The adverse events were however frequent with incidences of 37%, 47% and 31% respectively for hardware-, biological and stimulation-related side effects.

CONCLUSION

Neuromodulation can be beneficial for selected patients with intractable chronic migraine although frequent complications have been consistently reported across studies. Further research focusing on development of better hardware and technique optimisation and in particular reliable randomised trials with significantly longer follow-ups are warranted in this field.

Outcomes of Occipital Nerve Stimulation for Craniofacial Pain Syndromes

OBJECTIVES

Occipital nerve regional stimulation (ONS) is reported to improve pain in several studies. We examined long-term pain and functional outcomes of ONS in an open-label prospective study.

METHODS

Patients with medically refractory and disabling craniofacial pain were prospectively selected for ONS. Primary outcome was a change in mean daily pain intensity on the numeric pain rating scale (NPRS) at 6 months. Secondary outcomes included changes in NPRS, Headache Impact Test-6 (HIT-6), Migraine Disability Assessment (MIDAS), Pain Disability Index (PDI), Center for Epidemiologic Studies Depression Scale - Revised (CESD-R), and Short Form-36 version 2 (SF36) at last follow-up.

RESULTS

Thirteen patients (mean age 49.7 ± 8.4) diagnosed with occipital neuralgia (6), hemicrania continua (2), persistent idiopathic facial pain (2), post-traumatic facial pain (1), cluster headache (1), and chronic migraine (1) were enrolled. Mean NPRS improved by 2.1 ± 2.1 at 6 months and 2.1 ± 1.9 at last follow-up (23.5 ± 18.1 months). HIT-6 decreased by 8.7 ± 8.8, MIDAS decreased by 61.3 ± 71.6, and PDI decreased by 17.9 ± 18. SF36 physical functioning, bodily pain, and social functioning improved by 16.4 ± 19.6, 18.0 ± 31.6, and 26.1 ± 37.3, respectively. Moderate to severe headache days (defined as ≥50% of baseline mean NPRS) were reduced by 8.9 ± 10.2 days per month with ONS.

CONCLUSION

ONS reduced the long-term NPRS and moderate-severe monthly headache days by 30% and improved functional outcomes and quality of life. A prospective registry for ONS would be helpful in accumulating a larger cohort with longer follow-up in order to improve the use of ONS.

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.

Burst Occipital Nerve Stimulation for Chronic Migraine and Chronic Cluster Headache

BACKGROUND

Occipital nerve stimulation (ONS) is widely used for headache syndromes including chronic migraine (CM) and chronic cluster headache (CCH). The paraesthesia associated with tonic stimulation can be bothersome and can limit therapy. It is now clear in spinal cord stimulation that paraesthesia-free waveforms can produce effective analgesia, but this has not been reported in ONS for CM or CCH.

MATERIALS AND METHODS

Seventeen patients (12 CM and 5 CCH) were treated with bilateral burst pattern ONS, including 4 who had previously had tonic ONS. Results were assessed in terms of the frequency of headaches (number of headache days per month for CM, and number of attacks per day for CCH) and their intensity on the numeric pain rating scale.

RESULTS

Burst ONS produced a statistically significant mean reduction of 10.2 headache days per month in CM. In CCH, there were significant mean reductions in headache frequency (92%) and intensity (42%).

CONCLUSION

Paraesthesia is not necessary for good quality analgesia in ONS. Larger studies will be required to determine whether the efficacies of the two stimulation modes differ. Burst ONS is imperceptible and therefore potentially amenable to robustly blinded clinical trials.

Evolving Techniques and Indications in Peripheral Nerve Stimulation for Pain

Peripheral nerve stimulation is the direct electrical stimulation of named nerves outside the central neuraxis to alleviate pain in the distribution of the targeted peripheral nerve. These treatments have shown efficacy in treating a variety of neuropathic, musculoskeletal, and visceral refractory pain pathologies; although not first line, these therapies are an important part of the treatment repertoire for chronic pain. With careful patient selection and judicious choice of stimulation technique, excellent results can be achieved for a variety of pain etiologies and distributions. This article reviews current and past practices of peripheral nerve stimulation and upcoming advancements in the field.

Neurostimulation for the treatment of chronic migraine and cluster headache

Small subsets of patients who fail to respond to pharmacological treatment may benefit from alternative treatment methods. In the last decade, neurostimulation is being explored as a potential treatment option for the patients with chronic, severely disabling refractory primary headaches. To alleviate pain, specific nerves and brain areas have been stimulated, and various methods have been explored: deep brain stimulation, occipital nerve stimulation, and sphenopalatine ganglion stimulation are among the more invasive ones, whereas transcranial magnetic stimulation and supraorbital nerve stimulation are noninvasive. Vagal nerve stimulation can be invasive or noninvasive, though this review included only data for noninvasive VNS. Most of these methods have been tested in small open-label patient series; recently, more data from randomized, controlled, and blinded studies are available. Although neurostimulation treatments have demonstrated good efficacy in many studies, it still has not been established as a standard treatment in refractory patients. This review analyzes the available evidence regarding efficacy and safety of different neurostimulation modalities for the treatment of chronic migraine and cluster headache.

Therapeutic Approaches for the Management of Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgia (TAC) encompasses 4 unique primary headache types: cluster headache, paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms. They are grouped on the basis of their shared clinical features of unilateral headache of varying durations and ipsilateral cranial autonomic symptoms. The shared clinical features reflect the underlying activation of the trigeminal-autonomic reflex. The treatment for TACs has been limited and not specific to the underlying pathogenesis. There is a proportion of patients who are refractory or intolerant to the current standard medical treatment. From instrumental bench work research and neuroimaging studies, there are new therapeutic targets identified in TACs. Treatment has become more targeted and aimed towards the pathogenesis of the conditions. The therapeutic targets range from the macroscopic and structural level down to the molecular and receptor level. The structural targets for surgical and noninvasive neuromodulation include central neuromodulation targets: posterior hypothalamus and, high cervical nerves, and peripheral neuromodulation targets: occipital nerves, sphenopalatine ganglion, and vagus nerve. In this review, we will also discuss the neuropeptide and molecular targets, in particular, calcitonin gene-related peptide, somatostatin, transient receptor potential vanilloid-1 receptor, nitric oxide, melatonin, orexin, pituitary adenylate cyclase-activating polypeptide, and glutamate.

Invasive pericranial nerve interventions

Background

In many patients suffering from primary headaches, the available pharmacological and behavioural treatments are not satisfactory. This is a review of (minimally) invasive interventions targeting pericranial nerves that could be effective in refractory patients.

Methods

The interventions we will cover have in common pericranial nerves as targets, but are distinct according to their rationale, modality and invasiveness. They range from nerve blocks/infiltrations to the percutaneous implantation of neurostimulators and surgical decompression procedures. We have critically analysed the published data (PubMed) on their effectiveness and tolerability.

Results and conclusions

There is clear evidence for a preventative effect of suboccipital injections of local anaesthetics and/or steroids in cluster headache, while evidence for such an effect is weak in migraine. Percutaneous occipital nerve stimulation (ONS) provides significant long-term relief in more than half of drug-resistant chronic cluster headache patients, but no sham-controlled trial has tested this. The evidence that ONS has lasting beneficial effects in chronic migraine is at best equivocal. Suboccipital infiltrations are quasi-devoid of side effects, while ONS is endowed with numerous, though reversible, adverse events. Claims that surgical decompression of multiple pericranial nerves is effective in migraine are not substantiated by large, rigorous, randomized and sham-controlled trials.

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.

Long-term outcomes of occipital nerve stimulation for chronic migraine: a cohort of 53 patients

Background

Chronic migraine affects up to 2 % of the general population and has a substantial impact on sufferers. Occipital nerve stimulation has been investigated as a potentially effective treatment for refractory chronic migraine. Results from randomised controlled trials and open label studies have been inconclusive with little long-term data available.

Methods

The long-term efficacy, functional outcome and safety of occipital nerve stimulation was evaluated in an uncontrolled, open-label, prospective study of 53 intractable chronic migraine patients.

Results

Fifty-three patients were implanted in a single centre between 2007 and 2013. Patients had a mean age of 47.75 years (range 26–70), had suffered chronic migraine for around 12 years and had failed a mean of 9 (range 4–19) preventative treatments prior to implant. Eighteen patients had other chronic headache phenotypes in addition to chronic migraine. After a median follow-up of 42.00 months (range 6–97) monthly moderate-to-severe headache days (i.e. days on which pain was more than 4 on the verbal rating score and lasted at least 4 h) reduced by 8.51 days (p < 0.001) in the whole cohort, 5.80 days (p < 0.01) in those with chronic migraine alone and 12.16 days (p < 0.001) in those with multiple phenotypes including chronic migraine. Response rate of the whole group (defined as a >30 % reduction in monthly moderate-to-severe headache days) was observed in 45.3 % of the whole cohort, 34.3 % of those with chronic migraine alone and 66.7 % in those with multiple headache types. Mean subjective patient estimate of improvement was 31.7 %. Significant reductions were also seen in outcome measures such as pain intensity (1.34 points, p < 0.001), all monthly headache days (5.66 days, p < 0.001) and pain duration (4.54 h, p < 0.001). Responders showed substantial reductions in headache-related disability, affect scores and quality of life measures. Adverse event rates were favourable with no episodes of lead migration and only one minor infection reported.

Conclusions

Occipital nerve stimulation may be a safe and efficacious treatment for highly intractable chronic migraine patients even after relatively prolonged follow up of a median of over 3 years.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-016-0659-0) contains supplementary material, which is available to authorized users.

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.

Advanced Innovations for Pain

Chronic pain represents one of the most important public health problems in terms of both the number of patients afflicted and health care costs. Most patients with chronic pain are treated with medications as the mainstay of therapy, and yet most medically treated patients continue to report ongoing pain. Additionally, adverse effects from pain medications represent a major challenge for clinicians and patients. Spinal cord stimulation and intrathecal drug delivery systems are well-established techniques that have been utilized for over 25 years. Intrathecal drug delivery systems have proven efficacy for a wide variety of intractable pain conditions and fewer adverse effects than systemic medical therapy in patients with refractory cancer-related pain. Spinal cord stimulation is cost-effective and provides improved pain control compared with medical therapy in patients with a variety of refractory pain conditions including complex regional pain syndrome, painful diabetic neuropathy, and chronic radiculopathy. Patients who have intractable pain that has not responded to reasonable attempts at conservative pain care measures should be referred to a qualified interventional pain specialist to determine candidacy for the procedures discussed in this article.

Percutaneous nerve field stimulation (PENS) of the occipital region as a possible predictor for occipital nerve stimulation (ONS) responsiveness in refractory headache disorders? A feasibility study

Background

Occipital nerve stimulation (ONS) has been reported to diminish pain levels in intractable chronic headache syndromes of different origin. No reliable objective markers exist to predict ONS responsiveness. This study investigated the predictive value of occipital percutaneous nerve field stimulation (PENS) prior to ONS.

Methods

This trial included 12 patients (CCH, CM, PTH, CH) with chronic refractory headache syndromes eligible for ONS. Repetitive PENS (3 × /10 days) was performed and the headache severity/frequency monitored over four weeks before ONS implantation. Further assessment of PENS/ONS outcomes were stimulation-related complications, perception/tolerance stimulation threshold, the Migraine Disability Scale (MIDAS) and the Beck Depression Inventory (BDI).

Results

All PENS responders benefited from ONS. Of the seven PENS-nonresponders with VAS 6.1(±1.1), six experienced significant pain relief from ONS after three months and one patient failed the PENS/ONS trial (VAS 3.7 (±1.6)); (95% CI 3.6 to 5.7, p < 0.001). The VAS baseline was 8.4 (±0.5) and decreased significantly (50% reduction in severity/frequency) in five patients after PENS, while seven failed to improve (VAS 4.9 (±1.1); (95% CI 2.5 to 4.5, p < 0.001). BDI baseline (from 22.6 (±4.2) to 10.6 (±5.9) (95% CI 7.4 to 16.6, p < 0.001)) and MIDAS baseline (from 143.9 (±14.5) to 72.8 (±28.7) (95% CI 1.17 to 2.3, p < 0.001)) significantly declined after ONS. No PENS/ONS-related complications occurred.

Conclusions

Presurgical applied occipital PENS failed to identify ONS responders sufficiently according to our study protocol, thus requiring further specific investigations to determine its predictive usefulness.

Non-invasive vagus nerve stimulation for PREVention and Acute treatment of chronic cluster headache (PREVA): A randomised controlled study

Background

Chronic cluster headache (CH) is a debilitating disorder for which few well-controlled studies demonstrate effectiveness of available therapies. Non-invasive vagus nerve stimulation (nVNS) was examined as adjunctive prophylactic treatment of chronic CH.

Methods

PREVA was a prospective, open-label, randomised study that compared adjunctive prophylactic nVNS (n = 48) with standard of care (SoC) alone (control (n = 49)). A two-week baseline phase was followed by a four-week randomised phase (SoC plus nVNS vs control) and a four-week extension phase (SoC plus nVNS). The primary end point was the reduction in the mean number of CH attacks per week. Response rate, abortive medication use and safety/tolerability were also assessed.

Results

During the randomised phase, individuals in the intent-to-treat population treated with SoC plus nVNS (n = 45) had a significantly greater reduction in the number of attacks per week vs controls (n = 48) (−5.9 vs −2.1, respectively) for a mean therapeutic gain of 3.9 fewer attacks per week (95% CI: 0.5, 7.2; p = 0.02). Higher ≥50% response rates were also observed with SoC plus nVNS (40% (18/45)) vs controls (8.3% (4/48); p < 0.001). No serious treatment-related adverse events occurred.

Conclusion

Adjunctive prophylactic nVNS is a well-tolerated novel treatment for chronic CH, offering clinical benefits beyond those with SoC.

Peripheral nerve field stimulation for trigeminal neuralgia, trigeminal neuropathic pain, and persistent idiopathic facial pain

Objective

Peripheral nerve field stimulation (PNFS) is a promising modality for treatment of intractable facial pain. However, evidence is sparse. We are therefore presenting our experience with this technique in a small patient cohort.

Methods

Records of 10 patients (five men, five women) with intractable facial pain who underwent implantation of one or several subcutaneous electrodes for trigeminal nerve field stimulation were retrospectively analyzed. Patients’ data, including pain location, etiology, duration, previous treatments, long-term effects and complications, were evaluated.

Results

Four patients suffered from recurrent classical trigeminal neuralgia, one had classical trigeminal neuralgia and was medically unfit for microvascular decompression. Two patients suffered from trigeminal neuropathy attributed to multiple sclerosis, one from post-herpetic neuropathy, one from trigeminal neuropathy following radiation therapy and one from persistent idiopathic facial pain. Average patient age was 74.2 years (range 57–87), and average symptom duration was 10.6 years (range 2–17). Eight patients proceeded to implantation after successful trial. Average follow-up after implantation was 11.3 months (range 5–28). Using the visual analog scale, average pain intensity was 9.3 (range 7–10) preoperatively and 0.75 (range 0–3) postoperatively. Six patients reported absence of pain with stimulation; two had only slight constant pain without attacks.

Conclusion

PNFS may be an effective treatment for refractory facial pain and yields high patient satisfaction.

Concordant occipital and supraorbital neurostimulation therapy for hemiplegic migraine; initial experience; a case series

INTRODUCTION

Hemiplegic migraine is a particularly severe form of the disease that often evolves to a debilitating chronic illness that is resistant to commonly available therapies. Peripheral neurostimulation has been found to be a beneficial therapy for some patients among several diagnostic classes of migraine, but its potential has not been specifically evaluated for hemiplegic migraine.

MATERIALS AND METHODS

Four patients with hemiplegic migraine were treated with concordant, combined occipital and supraorbital neurostimulation over periods ranging 6-92 months. The clinical indicators followed included assessments of headache frequency and severity, frequency of hemiplegic episodes, functional impairment, medication usage, and patient satisfaction.

RESULTS

All reported a positive therapeutic response, as their average headache frequency decreased by 92% (30 to 2.5 headache days/month); Visual Analog Score by 44% (9.5 to 5.3); frequency of hemiplegic episodes by 96% (7.5 to 0.25 hemiplegic episodes/month); headache medication usage by 96% (6 to 0.25 daily medications); and Migraine Disability Assessment score by 98% (249 to 6). All were satisfied and would recommend the therapy, and all preferred combined occipital-supraorbital neurostimulation to occipital neurostimulation alone.

CONCLUSIONS

Concordant combined occipital and supraorbital neurostimulation may provide effective therapy for both the pain and motor aura in some patients with hemiplegic migraine.

Occipital nerve stimulation for chronic migraine--a systematic review and meta-analysis

BACKGROUND

Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine.

METHODS

Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n≥ 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots.

RESULTS

Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited.

CONCLUSIONS

While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed.

SYSTEMATIC REVIEW REGISTRATION

this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD42012002633.

The surgical technique of occipital nerve stimulation

BACKGROUND

Occipital nerve stimulation is increasingly used in the treatment of primary headache disorders. We describe a surgical technique applying preoperative fluoroscopy and intraoperative tactile orientation designed to reduce radiation exposure and provide reproducible results.

METHOD

Under general anesthesia and in the supine position, the C1-C2 transition is identified fluoroscopically and marked with an electrocardiogram (ECG) electrode prior to surgery. During electrode placement, the ECG electrodes are used for tactile orientation of electrode direction and depth.

CONCLUSIONS

The use of tactile orientation solely during surgery reduces radiation exposure and decreases the duration of surgery. This technique allows reproducible results of final electrode position.

Imaging sensory effects of occipital nerve stimulation: a new computer-based method in neuromodulation

BACKGROUND

Within the last years, occipital nerve stimulation (ONS) has proven to be an important method in the treatment of severe therapy-resistant neurological pain disorders. The correspondence between lead placement as well as possible stimulation parameters and the resulting stimulation effects remains unclear.

OBJECTIVE

The method aims to directly relate the neuromodulatory mechanisms with the clinical treatment results, to achieve insight in the mode of action of neuromodulation, to identify the most effective stimulation sets and to optimize individual treatment effects.

METHODS

We describe a new computer-based imaging method for mapping the spatial, cognitive and affective sensory effects of ONS. The procedure allows a quantitative and qualitative analysis of the relationship between lead positioning, the stimulation settings as well as the sensory and clinical stimulation effects.

CONCLUSION

A regular mapping of stimulation and sensory parameters allows a coordinated monitoring. The stimulation results can be reviewed and compared with regards to clinical effectiveness.

[Neuromodulation for neuropathic pain]

In pain therapy neurostimulation procedures have replaced the previously used lesional methods with only very few exceptions. This is especially true for neuropathic pain, i.e. pain which occurs as a direct consequence of a lesion or disease of the somatosensory system. Nowadays, various stimulation procedures are included in the neurosurgical and anesthesiological armamentarium for pain therapy, depending on the site of damage. This article gives an overview of the currently used invasive stimulation procedures and the indications.

Refractory headaches treated with bilateral occipital and temporal region stimulation

OBJECTIVES

To describe use of bilateral temporal and occipital stimulator leads for a refractory headache disorder.

MATERIALS AND METHODS

A 31-year-old female had a 10-year history of chronic, severe occipital and temporal region headaches. The patient underwent permanent implant of an occipital stimulator system that resulted in sustained, compete resolution of her occipital pain. However, she continued to suffer disabling (10/10) temporal region headaches and was bedbound most days of the week. Therefore, bilateral temporal stimulator leads were implanted and tunneled to her internal pulse generator.

RESULTS

At 12-month follow-up, the patient enjoyed sustained improvement in her pain scores (8/10) and marked increase in her level of functioning. Taking into account increased activity level, she rated her overall improvement at 50%. Unfortunately, infection and erosion of her right temporal lead necessitated temporal stimulator removal.

CONCLUSION

Headache disorders may require stimulation of all painful cephalic regions. However, our success in this case must be considered in light of the technical challenges and expense of placing stimulator leads subcutaneously around the head and neck, including the risk of infection, lead breakage, erosion, and migration.

A six year retrospective review of occipital nerve stimulation practice--controversies and challenges of an emerging technique for treating refractory headache syndromes

Background

A retrospective review of patients treated with Occipital Nerve Stimulation (ONS) at two large tertiary referral centres has been audited in order to optimise future treatment pathways.

Methods

Patient’s medical records were retrospectively reviewed, and each patient was contacted by a trained headache expert to confirm clinical diagnosis and system efficacy. Results were compared to reported outcomes in current literature on ONS for primary headaches.

Results

Twenty-five patients underwent a trial of ONS between January 2007 and December 2012, and 23 patients went on to have permanent implantation of ONS. All 23 patients reached one-year follow/up, and 14 of them (61%) exceeded two years of follow-up. Seventeen of the 23 had refractory chronic migraine (rCM), and 3 refractory occipital neuralgia (ON). 11 of the 19 rCM patients had been referred with an incorrect headache diagnosis. Nine of the rCM patients (53%) reported 50% or more reduction in headache pain intensity and or frequency at long term follow-up (11–77 months). All 3 ON patients reported more than 50% reduction in pain intensity and/or frequency at 28–31 months. Ten (43%) subjects underwent surgical revision after an average of 11 ± 7 months from permanent implantation - in 90% of cases due to lead problems. Seven patients attended a specifically designed, multi-disciplinary, two-week pre-implant programme and showed improved scores across all measured psychological and functional parameters independent of response to subsequent ONS.

Conclusions

Our retrospective review: 1) confirms the long-term ONS success rate in refractory chronic headaches, consistent with previously published studies; 2) suggests that some headaches types may respond better to ONS than others (ON vs CM); 3) calls into question the role of trial stimulation in ONS; 4) confirms the high rate of complications related to the equipment not originally designed for ONS; 5) emphasises the need for specialist multidisciplinary care in these patients.