Occipital Nerve Stimulation for Headache: Mechanisms and Efficacy

Occipital nerve stimulation: A detailed description of a surgical approach and a discussion on implantation techniques

OBJECTIVE

Occipital Nerve Stimulation (ONS) is increasingly used to treat a range of chronic, refractory headache conditions, most notably chronic cluster headache (CCH). Despite this, there is still no consensus on the optimal implantation technique. Clinical reports and reviews in the field have reported remarkably high complication rates of which several can be directly related to the surgical approach. We here describe a comprehensive and detailed surgical approach used at Aarhus University Hospital, Denmark, aiming to improve paresthesia coverage and minimize complications.

METHODS

The implantation procedure described here is performed with a sleep-awake anesthetic regimen in a lateral position using anatomical landmarks and perioperative testing based on patient feedback. A single lead is subcutaneously implanted from behind the ear and across the back of the head, and the implantable pulse generator (IPG) is placed below the right clavicle.

RESULTS

From March 2018 to June 2024, 45 CCH patients were implanted using this approach and followed up for a total of 86.3 patient years. A total of 22 adverse events (AEs) occurred in 17 patients, with nine AEs requiring revision surgery. Notably, no instances of lead migration, lead breakage, or muscle/neck stiffness were observed. Temporary occipital dysesthesia was the most frequent non-surgical AE, resolving spontaneously within weeks. The rate of serious adverse events (SAEs) was one per 9.6 patient years. Six patients had the ONS system explanted due to lack of efficacy.

CONCLUSIONS

The surgical approach described here in detail offers several advantages, with a favorable complication profile, satisfactory paresthesia coverage, and good perioperative patient comfort. Advances in the surgical technique are vital to both patients and healthcare providers, and we believe this approach is a valuable contribution toward improved patient outcomes and procedural efficiency.

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.

Treatment of chronic cluster headache with burst and tonic occipital nerve stimulation: A case series

OBJECTIVES AND BACKGROUND

Chronic cluster headache (CCH) is a rare but severely debilitating primary headache condition. A growing amount of evidence suggests that occipital nerve stimulation (ONS) can offer effective treatment in patients with severe CCH for whom conventional medical therapy does not have a sufficient effect. The paresthesia evoked by conventional (tonic) stimulation can be bothersome and may thus limit therapy. Burst ONS produces paresthesia-free stimulation, but the amount of evidence on the efficacy of burst ONS as a treatment for intractable CCH is scarce.

METHODS

In this case series, we report 15 patients with CCH treated with ONS at Aarhus University Hospital, Denmark, from 2013 to 2020. Nine of these received burst stimulation either as primary treatment or as a supplement to tonic stimulation. The results were assessed in terms of the frequency of headache attacks per week and their intensity on the Numeric Rating Scale, as well as the Patient Global Impression of Change (PGIC) with ONS treatment.

RESULTS

At a median (range) follow-up of 38 (16-96) months, 12 of the 15 patients (80%) reported a reduction in attack frequency of ≥50% (a reduction from a median of 35 to 1 attack/week, p < 0.001). Seven of these patients were treated with burst ONS. A significant reduction was also seen in maximum pain intensity. Overall, 10 patients stated a clinically important improvement in their headache condition following ONS treatment, rated on the PGIC scale. A total of 16 adverse events (nine of which were in the same patient) were registered.

CONCLUSION

Occipital nerve stimulation significantly reduced the number of weekly headache attacks and their intensity. Burst ONS seems to function well alone or as a supplement to conventional tonic ONS as a preventive treatment for CCH; however, larger prospective studies are needed to determine whether the effect can be confirmed and whether the efficacy of the two stimulation paradigms is even.

Symptoms and pathophysiology of cluster headache. Approach to combined occipital and supraorbital neurostimulation

Cluster headache (CH) is included under section 3 - Trigeminal autonomic cephalalgias (TAC) of the International Headache Society (IHS) classification. It is one of the most frequent, painful and disabling primary headaches. Acute and preventive pharmacological treatments are often poorly tolerated and of limited effectiveness. Due to improved understanding of the pathophysiology of CH, neuromodulation devices are now considered safe and effective options for preventive and acute treatment of CH. In this paper, we review the information available to date, and present the case of a patient with disabling cluster headache highly resistant to medical treatment who underwent implantation of a peripheral nerve neurostimulation system to stimulate the supraorbital nerves (SON) and greater occipital nerve (GON) in our Pain Unit. We also review the diagnostic criteria for CH, the state of the knowledge on the pathophysiology of CH, and the role played by neuromodulation in treating this condition.

Occipital Neuralgia: Advances in the Operative Management

Background

Occipital neuralgia (ON) is a primary headache disorder characterized by sharp, shooting, or electric shock-like pain in the distribution of the greater, lesser, or third occipital nerves.

Aim

To review the existing literature on the management of ON and to describe our technique of an endoscopic-assisted approach to decompress the GON proximally in areas of fibrous and muscular compression, as well as distally by thorough decompression of the occipital artery from the nerve.

Methods

Relevant literature on the medical and surgical management of ON was reviewed. Literature on the anatomical relationships of occipital nerves and their clinical relevance were also reviewed.

Results

While initial treatment of ON is conservative, peripheral nerve blocks and many surgical management approaches are available for patients with pain refractory to the medical treatment. These include greater occipital nerve blocks, occipital nerve stimulation, Botulinum toxin injections locally, pulsed radiofrequency ablation, cryoneuroablation, C-2 ganglionectomy, and endoscopic-assisted ON decompression.

Conclusion

Patients of ON refractory to medical management can be benefitted by surgical approaches and occipital nerve blocks. Endoscopic-assisted ON decompression provides one such approach for the patients with vascular, fibrous or muscular compressions of occipital nerves resulting in intractable ON.

Changes in peripheral and central sensitization in patients undergoing occipital nerve stimulation

Introduction

Central sensitization and impaired conditioned pain modulation (CPM) response have been reported to contribute to migraine progression. Migraine patients can present with allodynia possibly attributed to increased sensitivity of peripheral ends of nociceptors with both peripheral and central sensitization. Occipital nerve stimulation (ONS) works by stimulating the distal branches of C1, C2 and C3 possibly altering the nociceptive traffic to the trigemino-cervical complex, brainstem and supranuclear connections.

Aims

This observational study explores peripheral and central sensitization in patients undergoing percutaneous ONS.

Methods

Following local regulatory approval, 13 patients undergoing ONS with dual Octrode 90 cm leads and rechargeable implantable pulse generator (IPG) (St Jude) were recruited to have quantitative sensory testing (QST) pre- and post-procedure 2 weeks, 1, 3, 6 and 12 months.

Results

Patients with intractable migraine demonstrated impaired CPM (mean baseline pressure pain thresholds (PPTs): 61.98 kPa vs 48.01 kPa cuff inflated) prior to ONS, reverting to an efficient CPM response within 2 weeks following ONS implant (68.9 kPa vs 104.5 kPa cuff inflated) and continuing positively over the next 12 months. In contrast, no statistical difference was observed in PPTs.

Conclusion

This is the first reported observation highlighting the effects on central sensitization following ONS. A consistent and sustained improvement in CPM was observed in contrast to PPT's where there was no difference. Normalisation of the CPM response following ONS indicates that the treatment may reduce central sensitization in the migraine population.

Neurostimulation methods in the treatment of chronic pain

The goal of this narrative review was to give an up-to-date overview of the peripheral and central neurostimulation methods that can be used to treat chronic pain. Special focus has been given to three pain conditions: neuropathic pain, nociplastic pain and primary headaches. Both non-invasive and invasive techniques are briefly presented together with their pain relief potentials. For non-invasive stimulation techniques, data concerning transcutaneous electrical nerve stimulation (TENS), transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), remote electrical neuromodulation (REN) and vagus nerve stimulation (VNS) are provided. Concerning invasive stimulation techniques, occipital nerve stimulation (ONS), vagus nerve stimulation (VNS), epidural motor cortex stimulation (EMCS), spinal cord stimulation (SCS) and deep brain stimulation (DBS) are presented. The action mode of all these techniques is only partly understood but can be very different from one technique to the other. Patients' selection is still a challenge. Recent consensus-based guidelines for clinical practice are presented when available. The development of closed-loop devices could be of interest in the future, although the clinical benefit over open loop is not proven yet.

Persistent Idiopathic Facial Pain Originating from Cervical Abnormalities

BACKGROUND

Persistent idiopathic facial pain is characterized by persistent facial or oral pain in the absence of a neurologic deficit. This underexplored pain may be conducted by various nerves, including cranial nerves and upper cervical spinal roots, and its etiology is unclear.

CASE DESCRIPTION

A patient presented with persistent idiopathic facial pain associated with occipital muscle stiffness after an improper neck massage. The patient achieved almost complete pain relief by coblation of right upper cervical nerves (C1 and C2 spinal roots) followed by continuous cervical epidural analgesia for a period of 3 weeks. The analgesic effect was stable during the 3-month follow-up period.

CONCLUSIONS

Persistent idiopathic facial pain may be cervicogenic, and treatments focusing on cervical spinal roots may provide satisfactory pain control in patients with cervical abnormalities.

Facial Sensory Restoration After Trigeminal Sensory Rhizotomy by Collateral Sprouting From the Occipital Nerves

BACKGROUND AND IMPORTANCE

Lesioning procedures are effective for trigeminal neuralgia (TN), but late pain recurrence associated with sensory recovery is common. We report a case of recurrence of type 1A TN and recovery of facial sensory function after trigeminal rhizotomy associated with collateral sprouting from upper cervical spinal nerves.

CLINICAL PRESENTATION

A 41-yr-old woman presented 2 yr after open left trigeminal sensory rhizotomy for TN with pain-free anesthesia in the entire left trigeminal nerve distribution. Over 18 mo, she developed gradual recovery of facial sensation migrating anteromedially from the occipital region, eventually extending to the midpupillary line across the distribution of all trigeminal nerve branches. She reported recurrence of her triggered lancinating TN pain isolated to the area of recovered sensation with no pain in anesthetic areas. Nerve ultrasound demonstrated enlargement of ipsilateral greater and lesser occipital nerves, and occipital nerve block restored facial anesthesia and resolved her pain, indicating that recovered facial sensation was provided exclusively by the upper cervical spinal nerves. She underwent C2/C3 ganglionectomy, and ganglia were observed to be hypertrophic. Postoperatively, trigeminal anesthesia was restored with complete resolution of pain that persisted at 12-mo follow-up.

CONCLUSION

This is the first documented case of a spinal nerve innervating a cranial dermatome by collateral sprouting after cranial nerve injury. The fact that typical TN pain can occur even when sensation is mediated by spinal nerves suggests that the disorder can be centrally mediated and late failure after lesioning procedures may result from maladaptive reinnervation.

A Neuroscience Perspective of Physical Treatment of Headache and Neck Pain

The most prevalent primary headaches tension-type headache and migraine are frequently associated with neck pain. A wide variety of treatment options is available for people with headache and neck pain. Some of these interventions are recommended in guidelines on headache: self-management strategies, pharmacological and non-pharmacological interventions. Physical treatment is a frequently applied treatment for headache. Although this treatment for headache is predominantly targeted on the cervical spine, the neurophysiological background of this intervention remains unclear. Recent knowledge from neuroscience will enhance clinical reasoning in physical treatment of headache. Therefore, we summarize the neuro- anatomical and—physiological findings on headache and neck pain from experimental research in both animals and humans. Several neurophysiological models (referred pain, central sensitization) are proposed to understand the co-occurrence of headache and neck pain. This information can be of added value in understanding the use of physical treatment as a treatment option for patients with headache and neck pain.

Location and Volume of MRI Artifacts in Patients With Implanted Sphenopalatine Ganglion Neurostimulators for Treatment of Chronic Cluster Headache

INTRODUCTION

Sphenopalatine ganglion stimulation (SPG-S) is an invasive form of neuromodulation by which a neurostimulator is implanted into the pterygopalatine fossa to treat refractory chronic cluster headache. The implant is MRI conditional, up to 3 T, however there is no clinical data on the shape, size, and location of the artifact produced by the implant.

MATERIALS AND METHODS

Records of patients with SPG-S were analyzed for postoperative cranial MRI scans. MRI and intraoperative CT scans for visualization of the implant were fused and volumetry was performed for both the implant and the MRI artifact in different MRI sequences.

RESULTS

In total, n = 3 patients with postoperative MRI scans were identified. The mean CT artifact volume was 0.73 cm³ (±0.15 cm³ ). MRI artifact volume differed between sequences (range: 25.2-220.7 cm³ ). The intracranial space was largely unaffected besides the pole of the ipsilateral temporal lobe and the basal frontal gyrus. MRI artifacts affected the extracranial space (orbit, maxillary and ethmoid sinuses, and parts of the parotid gland). No adverse events occurred during or after MRI scans.

CONCLUSIONS

Cranial MRI scans with SPG-S implants were safely performed in three patients following the manufacturer's MRI conditions. MRI artifacts were mostly located in the extracranial space. Brain MRI imaging is largely unaffected.

CONFLICT OF INTEREST

The authors declare no potential conflicts of interest with respect to research, authorship, and/or publication of this article.

Cluster headache: new targets and options for treatment

Cluster headache is a severe headache disorder with considerable impact on quality of life. The pathophysiology of the disease remains poorly understood. With few specific targets for treatment, current guidelines mainly include off-label treatment with medication. However, new targets for possible treatment options are emerging. Calcitonin gene-related peptide (CGRP)-targeted medication could become the first (cluster) headache-specific treatment option. Other exciting new treatment options include invasive and non-invasive neuromodulation techniques. Here, we provide a short overview of new targets and treatment options that are being investigated for cluster headache.

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.

Safety and Efficacy of Occipital Nerves Stimulation for the Treatment of Chronic Migraines: Randomized, Double-blind, Controlled Single-center Experience

BACKGROUND

A recent multicenter study presented 52-week safety and efficacy results from an open-label extension of a randomized, sham-controlled trial for patients with chronic migraine (CM) undergoing peripheral nerve stimulation of the occipital nerves. We present the data from a single center of 20 patients enrolled at the Cleveland Clinic's Pain Management Department.

METHODS

In this single center, 20 patients were implanted with a neurostimulation system, randomized to an active or control group for 12 weeks, and received open-label treatment for an additional 40 weeks. Outcomes collected included number of headache days, pain intensity, Migraine Disability Assessment (MIDAS), Zung Pain and Distress (PAD), direct patient reports of headache pain relief, quality of life, satisfaction, and adverse events (AEs).

RESULTS

Headache days per month were reduced by 8.51 (±9.81) days (P < 0.0001). The proportion of patients who achieved a 30% and 50% reduction in headache days and/or pain intensity was 60% and 35%, respectively. MIDAS and Zung PAD were reduced for all patients. Fifteen (75%) of the 20 patients at the site reported at least one AE. A total of 20 AEs were reported from the site.

CONCLUSION

Our results support the 12-month efficacy of 20 CM patients receiving peripheral nerve stimulation of the occipital nerves in this single-center trial.

The surgical management of cephalalgia

PURPOSE OF REVIEW

Management of headache disorders is not part of most craniomaxillofacial surgery practices; however there are certain indications for surgical management of headaches by the craniomaxillofacial surgeon.

RECENT FINDINGS

Migraine headaches are the most amenable to surgical management and while the exact mechanism of migraine is unknown, a central or peripheral trigger such as compressive neuropathy of trigeminal nerve branches leading to neurogenic inflammation has been suggested. The primary management for episodic migraine headache should be lifestyle modification and medication, whereas for chronic migraine (>15 headache days/month) use of medication and botulinum neurotoxin is effective, whereas some patients may choose to explore surgical options. Trigger site decompression for chronic migraine surgically relieves anatomic impingement at various sites and has been shown to reduce by at least 50% the frequency, intensity, and duration of headaches in over 85% and elimination of headaches in almost 60%. Trigger points may also lead to exacerbation of cluster headaches and treatment with botulinum neurotoxin may reduce attacks.

SUMMARY

Trigger site decompression is an effective treatment for chronic migraine, as are botulinum neurotoxin injections in reducing attacks in cluster headaches. The craniomaxillofacial surgeon is uniquely qualified to treat these primary headache disorders.

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.

Neuromodulation in cluster headache

Medically refractory chronic cluster headache (CH) is a severely disabling headache condition for which several surgical procedures have been proposed as a prophylactic treatment. None of them have been evaluated in controlled conditions, only open studies and case series being available. Destructive procedures (radiofrequency lesioning, radiosurgery, section) and microvascular decompression of the trigeminal nerve or the sphenopalatine ganglion (SPG) have induced short-term improvement which did not maintain on long term in most of the patients. They carried a high risk of complications, including severe sensory loss and neuropathic pain, and consequently should not be proposed in first intention.Deep brain stimulation (DBS), targeting the presumed CH generator in the retro-hypothalamic region or fibers connecting it, decreased the attack frequency >50 in 60 % of the 52 patients reported. Complications were infrequent: gaze disturbances, autonomic disturbances, and intracranial hemorrhage (2).Occipital nerve stimulation (ONS) was efficient (decrease of attack frequency >50 %) in about 70 % of the 60 patients reported, with a low risk of complications (essentially hardware related). Considering their respective risks, ONS should be proposed first and DBS only in case of ONS failure.New on-demand chronically implanted SPG stimulation seemed to be efficient to abort CH attacks in a pilot controlled trial, but its long-term safety needs to be further studied.

A systematic review of peripheral nerve interventional treatments for chronic headaches

OBJECTIVE

This study aimed to systematically compare the outcomes of different types of interventional procedures offered for the treatment of headaches and targeted toward peripheral nerves based on available published literature.

BACKGROUND

Multiple procedural modalities targeted at peripheral nerves are being offered to patients for the treatment of chronic headaches. However, few resources exist to compare the effectiveness of these modalities. The objective of this study was to systematically review the literature to compare the published outcomes and effectiveness of peripheral nerve surgery, radiofrequency (RF) therapy, and peripheral nerve stimulators for chronic headaches, migraines, and occipital neuralgia.

METHODS

A broad literature search of the MEDLINE and CENTRAL (Cochrane) databases was undertaken. Relevant studies were selected by 2 independent reviewers and these results were narrowed further by the application of predetermined inclusion and exclusion criteria. Studies were assessed for quality, and data were extracted regarding study characteristics (study type, level of evidence, type of intervention, and number of patients) and objective outcomes (success rate, length of follow-up, and complications). Pooled analysis was performed to compare success rates and complications between modality types.

RESULTS

Of an initial 250 search results, 26 studies met the inclusion criteria. Of these, 14 articles studied nerve decompression, 9 studied peripheral nerve stimulation, and 3 studied RF intervention. When study populations and results were pooled, a total of 1253 patients had undergone nerve decompression with an 86% success rate, 184 patients were treated by nerve stimulation with a 68% success rate, and 131 patients were treated by RF with a 55% success rate. When compared to one another, these success rates were all statistically significantly different. Neither nerve decompression nor RF reported complications requiring a return to the operating room, whereas implantable nerve stimulators had a 31.5% rate of such complications. Minor complication rates were similar among all 3 procedures.

CONCLUSIONS

Of the 3 most commonly encountered interventional procedures for chronic headaches, peripheral nerve surgery via decompression of involved peripheral nerves has been the best-studied modality in terms of total number of studies, level of evidence of published studies, and length of follow-up. Reported success rates for nerve decompression or excision tend to be higher than those for peripheral nerve stimulation or for RF, although poor study quantity and quality prohibit an accurate comparative analysis. Of the 3 procedures, peripheral nerve stimulator implantation was associated with the greatest number of complications. Although peripheral nerve surgery seems to be the interventional treatment modality that is currently best supported by the literature, better controlled and normalized high-quality studies will help to better define the specific roles for each type of intervention.

Salvage treatment of trigeminal neuralgia by occipital nerve stimulation

BACKGROUND

Although most patients suffering from trigeminal neuralgia (TN) respond to medical or surgical treatment, nonresponders remain in very severe painful condition.

CASE RESULT

We describe for the first time a case of severe refractory classical TN treated successfully (follow-up one year) by chronic bilateral occipital nerve stimulation (ONS), because other classic medical and surgical options failed or could not be performed.

CONCLUSIONS

This single case suggests that ONS might be offered to TN patients refractory both to standard drugs and interventions, with a favorable risk/benefit ratio, although its long-term efficacy remains unknown.

Neurostimulation in cluster headache: A review of current progress

Purpose of review

Neurostimulation has emerged as a viable treatment for intractable chronic cluster headache. Several therapeutic strategies are being investigated including stimulation of the hypothalamus, occipital nerves and sphenopalatine ganglion. The aim of this review is to provide an overview of the rationale, methods and progress for each of these.

Latest findings

Results from a randomized, controlled trial investigating sphenopalatine ganglion stimulation have just been published. Reportedly the surgery is relatively simple and it is apparently the only therapy that provides relief acutely.

Summary

The rationale behind these therapies is based on growing evidence from clinical, hormonal and neuroimaging studies. The overall results are encouraging, but unfortunately not all patients have benefited. All the mentioned therapies require weeks to months of stimulation for a prophylactic effect to occur, suggesting brain plasticity as a possible mechanism, and only stimulation of the sphenopalatine ganglion has demonstrated an acute, abortive effect. Predictors of effect for all modes of neurostimulation still need to be identified and in the future, the least invasive and most effective strategy must be preferred as first-line therapy for intractable chronic cluster headache.

Occipital stimulation for chronic migraine: patient selection and complications

BACKGROUND

Chronic migraine is a significant cause of disability world-wide and occipital region stimulation (OS) has been proposed to treat it. While participating in an industry-sponsored pilot trial of OS, we aimed to collect data regarding our surgical complications and long term usage of OS in our chronic migraine patients.

METHODS

Ten patients (8 female, median age 46.5 years) were enrolled based on criteria established by the sponsoring company, screened in the headache clinic, and followed for a median of 33 months. We did not access data collected by industry for this report and instead collected our own data prospectively, including predominant location of headache, location of paresthesia evoked by OS, and complications.

RESULTS

Adverse events included three possible early infections requiring antibiotics but not hardware removal, one late implantable pulse generator erosion requiring removal, one generator malfunction requiring revision, and loss of paresthetic coverage requiring four revisions in four patients. Two patients experienced new symptoms requiring psychiatric intervention. Five patients had no benefit and have been explanted. Of those who remain using their device, the proportion of their pre-operative pain located in the occipital region was 0.62 ± 0.14, whereas in those patients who have been explanted, the proportion was 0.31 ± 0.18 (t = 3.15, p=0.01).

CONCLUSIONS

Complication rates with OS are higher than those seen with other stimulation techniques, despite identical hardware and similar surgery. The location of migraine pain did predict outcome, and suggests that only those with primarily occipital region headache are candidates for this therapy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

Clinical trials.gov (NCT00615342).

Occipital Nerve Stimulation for Refractory Headache in the Chiari Malformation Population

BACKGROUND:

Chronic occipital and suboccipital headache is a common symptom in patients with Chiari I malformation. These headaches may persist despite appropriate surgical treatment of the underlying pathology via suboccipital decompression, duraplasty, and cerebrospinal fluid diversion. Occipital nerve stimulation has been shown to be effective in the treatment of a variety of occipital headache/pain syndromes.

OBJECTIVE:

To review retrospectively our experience with occipital nerve stimulation in patients with a primary diagnosis of Chiari malformation and a history of chronic occipital pain intractable to medical and surgical therapies.

METHODS:

We present a retrospective analysis of our series of 22 patients with Chiari malformation and persistent occipital headaches who underwent occipital neurostimulator trials and, after successful trials, permanent stimulator placement. A trial was considered successful with &gt; 50% pain relief as assessed with a standard Visual Analog Scale score. Patients with a successful trial underwent permanent placement approximately 1 to 2 weeks later. Patients were assessed postoperatively for pain relief via the Visual Analog Scale.

RESULTS:

Sixty-eight percent of patients (15 of 22) had a successful stimulator trial and proceeded to permanent implantation. Of those implanted, 87% (13 of 15) reported continued pain relief at a mean follow-up of 18.9 months (range, 6–51 months). Device-related complications requiring additional surgeries occurred in 40% of patients.

CONCLUSION:

Occipital stimulation may provide significant long-term pain relief in selected Chiari I malformation patients with persistent occipital pain. Larger and longer-term studies are needed to further define appropriate patient selection criteria and to refine the surgical technique to minimize device-related complications.

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.

Treatment of refractory chronic cluster headache by chronic occipital nerve stimulation

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

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

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

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

Patient outcome in migraine prophylaxis: the role of psychopharmacological agents

INTRODUCTION

Migraine is a serious illness that needs correct treatment for acute attacks and, in addition, a treatment prophylaxis, since patients with migraine suffer during acute attacks and also between attacks.

METHODS

A systematic review of the most relevant clinical trials of migraine headache and its epidemiology, pathophysiology, comorbidity, and prophylactic treatment (medical and nonmedical) was carried out using "Medline" and "PsychINFO" from 1973 to 2009. Approximately 110 trials met our inclusion criteria and were included in the current review.

RESULTS

The most effective pharmacological treatment for migraine prophylaxis is propranolol and anticonvulsants such as topiramate, valproic acid, and amitriptyline. Nonmedical treatments such as acupuncture, biofeedback, and melatonin have also been proposed. Peripheral neurostimulation has been suggested for the treatment of chronic daily headache that does not respond to prophylaxis and for the treatment of drug-resistant primary headache. The majority of the pharmacological agents available today have limited efficacy and may cause adverse effects incompatible with long-term use.

LIMITATIONS

The review was limited by the highly variable and often insufficient reporting of the complex outcome data and by the fact that migraine prophylaxis trials typically use headache diaries to monitor the course of the disease. The results of the different studies were also presented in different ways, making comparison of the results difficult.

DISCUSSION

An adequate prophylaxis is crucial in reducing disability and preventing the evolution of the problem into a chronic progressive illness. The implications of the present findings were discussed.

Positional cluster-like headache. A case report of a neurovascular compression between the third cervical root and the vertebral artery

Symptomatic cluster-like headaches have been described with lesions of the trigeminal and parasympathetic systems. Here, we report the case of a 44-year-old woman with continuous auricular pain and a positional cluster-like headache associated with red ear syndrome. Clinical data and morphological investigations raised the hypothesis of a neurovascular compression between the C3 root and vertebral artery. Neurosurgical exploration found a fibrosis surrounding both the C3 root and the vertebral artery. The excellent outcome after microvascular cervical decompression suggests a causal relationship between the cluster-like headache and the vertebral constraint on the C3 root.

Peripheral nerve blocks and trigger point injections in headache management - a systematic review and suggestions for future research

Interventional procedures such as peripheral nerve blocks (PNBs) and trigger point injections (TPIs) have long been used in the treatment of various headache disorders. There are, however, little data on their efficacy for the treatment of specific headache syndromes. Moreover, there is no widely accepted agreement among headache specialists as to the optimal technique of injection, type, and doses of the local anesthetics used, and injection regimens. The role of corticosteroids in this setting is also debated. We performed a PubMed search of the literature to find studies on PNBs and TPIs for headache treatment. We classified the abstracted studies based on the procedure performed and the treated condition. We found few controlled studies on the efficacy of PNBs for headaches, and virtually none on the use of TPIs for this indication. The most widely examined procedure in this setting was greater occipital nerve block, with the majority of studies being small and non-controlled. The techniques, as well as the type and doses of local anesthetics used for nerve blockade, varied greatly among studies. The specific conditions treated also varied, and included both primary (eg, migraine, cluster headache) and secondary (eg, cervicogenic, posttraumatic) headache disorders. Trigeminal (eg, supraorbital) nerve blocks were used in few studies. Results were generally positive, but should be taken with reservation given the methodological limitations of the available studies. The procedures were generally well tolerated. Evidently, there is a need to perform more rigorous clinical trials to clarify the role of PNBs and TPIs in the management of various headache disorders, and to aim at standardizing the techniques used for the various procedures in this setting.

Occipital nerve stimulation for headache disorders

Occipital nerve stimulation (ONS) was originally described in the treatment of occipital neuralgia. However, the spectrum of possible indications has expanded in recent years to include primary headache disorders, such as migraine and cluster headaches. Retrospective and some prospective studies have yielded encouraging results, and evidence from controlled clinical trials is emerging, offering hope for refractory headache patients. In this article we discuss the scientific rationale to use ONS to treat headache disorders, with emphasis on the trigeminocervical complex. ONS is far from a standardized technique at the moment and the recent literature on the topic is reviewed, both with respect to the procedure and its possible complications. An important way to move forward in the scientific evaluation of ONS to treat refractory headache is the clinical phenotyping of patients to identify patients groups with the highest likelihood to respond to this modality of treatment. This requires multidisciplinary assessment of patients. The development of ONS as a new treatment for refractory headache offers an exciting prospect to treat our most disabled headache patients. Data from ongoing controlled trials will undoubtedly shed new light on some of the unresolved questions.

Acute and preventive treatment of cluster headache and other trigeminal autonomic cephalgias

Patients with cluster headache or any of the trigeminal autonomic cephalalgias (TACs) are often good candidates for preventive treatment as their headaches are frequent and severe. While acute and symptomatic therapies must be used often, they do not alter the course of the cluster period or the duration of the TACs, and they do not usually decrease the frequency of attacks. In this chapter we discuss the aim and the choice of prevention. Verapamil is considered the first choice for prevention of cluster headache, but as with all of the medications to be mentioned, it has various adverse effects to be aware of. Other frequently used preventives for cluster include lithium carbonate, methysergide where available, methylergonovine, clonidine, melatonin, valproate, gabapentin, topiramate, and others. Several other medications can be used as bridge therapy, to decrease the frequency of cluster temporarily, giving time for the preventives to begin to work. The most commonly used bridge therapies are 7-21 days of prednisone at high and then tapering doses and ergots such as ergotamine tartrate and dihydroergotamine. Patients with chronic cluster headache who are unresponsive to all medical therapies can be considered for occipital nerve stimulation and various surgical procedures such as ganglyogliolysis of all three branches of the ipsilateral trigeminal nerve at the root entry zone. A somewhat controversial but highly successful procedure, at least as done by the neurosurgeons in Professor Bussone's group at the Institute of Neurology in Milan, has been deep-brain stimulation of the posterior hypothalamus. Other TACs, such as short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), can be hard to treat effectively with medications, but the paroxysmal hemicranias and cluster tic respond somewhat better to traditional therapies.

The face of chronic migraine: epidemiology, demographics, and treatment strategies

Chronic daily headache (CDH) represents a therapeutic challenge for many clinicians. Treatment strategies should be aimed at correctly identifying the presence of CDH. In addition, an effective prophylactic regimen should be initiated; the presence of medication overuse must be addressed, and the offending medication being overused must be discontinued. Aside from analgesic overuse, other modifiable risk factors associated with the development of chronic migraine and CDH must be addressed including obesity and caffeine use and the effective management of comorbid conditions such as depression, anxiety, and sleep-related breathing disorders.

Neurostimulation approaches to primary headache disorders

PURPOSE OF REVIEW

Conventional management options in medically intractable chronic-headache syndromes, such as chronic migraine, chronic cluster headache and hemicrania continua, are often limited. This review summarizes the current concepts, approaches and outcome data of invasive device-based neurostimulation approaches using occipital-nerve stimulation and deep-brain stimulation.

RECENT FINDINGS

Recently, there has been considerable progress in neurostimulation approaches to medically intractable chronic-headache syndromes. Previous studies have analysed the safety and efficacy of suboccipital neurostimulation in drug-resistant chronic-headache syndromes such as in chronic migraine, chronic cluster headache and hemicrania continua. The studies suggest suboccipital neurostimulation can have an effect even decades after onset of headaches, thus representing a possible therapeutic option inpatients that do not respond to any medication. Similarly, to date over 50 patients with cluster headaches underwent hypothalamic deep-brain stimulation. From these, an average of 50-70% did show a significant positive response.

SUMMARY

These findings will help to further elucidate the clinical potential of neurostimulation in chronic headache.

Occipital nerve stimulation (ONS). Surgical technique and prevention of late electrode migration

Occipital nerve stimulation (ONS) is an emerging procedure for the treatment of cranio-facial pain syndromes and headaches refractory to conservative treatments. The aim of this report is to describe in detail the surgical intervention and to introduce some useful tricks that help to avoid late displacement and migration of the suboccipital leads. The careful description of the surgical steps may contribute to a standardization of the procedure and make the interpretation of results easier even if obtained in series of patients operated on by different authors.

Myofascial trigger points in cluster headache patients: a case series

Active myofascial trigger points (MTrPs) have been found to contribute to chronic tension-type headache and migraine. The purpose of this case series was to examine if active trigger points (TrPs) provoking cluster-type referred pain could be found in cluster headache patients and, if so, to evaluate the effectiveness of active TrPs anaesthetic injections both in the acute and preventive headache's treatment. Twelve patients, 4 experiencing episodic and 8 chronic cluster headache, were studied. TrPs were found in all of them. Abortive infiltrations could be done in 2 episodic and 4 chronic patients, and preemptive infiltrations could be done in 2 episodic and 5 chronic patients, both kind of interventions being successful in 5 (83.3%) and in 6 (85.7%) of the cases respectively. When combined with prophylactic drug therapy, injections were associated with significant improvement in 7 of the 8 chronic cluster patients. Our data suggest that peripheral sensitization may play a role in cluster headache pathophysiology and that first neuron afferent blockade can be useful in cluster headache management.