Analysis of Adverse Events in the Management of Chronic Migraine by Peripheral Nerve Stimulation

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.

Anchoring of a mental nerve stimulator for treatment of facial neuropathic pain: a case illustration

INTRODUCTION

Mental nerve stimulation is recognised as a treatment option for neuropathic facial pain. Historically however, lead migration across the mobile temporomandibular joint has prevented this procedures utility.

METHODS

We describe a new method of insertion and anchoring of a mental nerve stimulator for the management of refractory neuropathic pain in the distribution of the mental nerve. We anchored the stimulator lead to the mandibular body.

RESULTS

Significant analgesic effect was achieved and no lead migration had occurred at 1 year post-operatively.

CONCLUSIONS

This report describes in detail the procedure of mental nerve stimulator insertion, with a novel technique of mandibular anchoring of the lead.

Preoperative Counseling in Spinal Cord Stimulation: A Designated Driver in Implantable Pulse Generator-Related Inconveniences?

BACKGROUND

Spinal cord stimulation (SCS) has been reported to cause substantial pain relief and improved quality of life (QoL) in patients with persistent spinal pain syndrome (PSPS). Despite implantable pulse generator (IPG)-related inconveniences such as pain, shame, and discomfort affecting QoL and patient satisfaction, these are often neglected. Hence, the current study aims to determine the associations between patient satisfaction, IPG-related inconveniences, and preoperative counseling in a homogeneous group of patients with PSPS receiving SCS with IPG implantation in the gluteal or abdominal area.

MATERIALS AND METHODS

Retrospective data on sample characteristics were gathered from the EPIC (electronic health record software) digital patient data base. Prospective data on patient satisfaction were obtained with a questionnaire that covered various topics such as shame, pain, disturbances in daily/intense activities, night rest and/or sleep, discomfort caused by clothing, and preoperative counseling. The exact location of the IPG and its scar were determined with photo analysis. Thereafter, the site of IPG placement was classified into separate quadrants within the gluteal and abdominal area. Patient satisfaction was defined as accepting the current location of the IPG without having the wish to undergo revision surgery.

RESULTS

In total, 81 participants (50.9 ± 10 years) were included in this analysis, with patient satisfaction observed in 61 patients (75.3%). Among satisfied patients, more extensive preoperative counseling concerning IPG pain and discomfort was reported compared with patients who were not satisfied (p < 0.001). When comparing the two groups, significant differences were found in shame (8/81, 9.9%), IPG site pain (21/81, 25.9%), disturbance of activities (42/81, 51.9%), and clothing-related discomfort (42/81, 51.9%).

CONCLUSIONS

On the basis of the current results, shared decision-making and comprehensive preoperative provision of information are recommended to optimize patient satisfaction regarding IPG pain, discomfort, and inconveniences. Although many patients experience these disadvantages despite successful SCS for pain related to PSPS, most of them accept this if they have received adequate preoperative information about expectations.

Digital subtraction angiography-guided peripheral nerve stimulation via the foramen rotundum for refractory trigeminal postherpetic neuralgia: a case report and literature review

Postherpetic neuralgia (PHN) is a debilitating complication of varicella-zoster virus infection. This case report presents a novel approach to treating refractory trigeminal maxillary postherpetic neuralgia using digital subtraction angiography (DSA)-guided peripheral nerve stimulation via the foramen rotundum. A 72-year-old female with severe, treatment-resistant pain underwent this intervention. The results demonstrated the disappearance of tactile allodynia, a significant reduction in oral analgesic requirements, and no observed complications or side effects during a 3-year follow-up period. This case highlights the potential effectiveness of DSA-guided peripheral nerve stimulation using a new dorsal root ganglion (DRG) stimulator as an alternative therapy for refractory trigeminal postherpetic neuralgia (TPHN).

Neuromodulation for Craniofacial Pain and Headaches

Headaches and facial pain are highly prevalent diseases but are often difficult to treat. Though there have been significant advances in medical management, many continue to suffer from refractory pain. Neuromodulation has been gaining interest for its therapeutic purposes in many chronic pain conditions, including headaches and facial pain. There are many potential targets of neuromodulation for headache and facial pain, and some have more robust evidence in favor of their use than others. Despite the need for more high-quality research, the available evidence for the use of neuromodulation in treating headaches and facial pain is promising. Considering the suffering that afflicts patients with intractable headache, neuromodulation may be an appropriate tool to improve not only pain but also disability and quality of life.

A prospective open label 2-8 year extension of the randomised controlled ICON trial on the long-term efficacy and safety of occipital nerve stimulation in medically intractable chronic cluster headache

BACKGROUND

We demonstrated in the randomised controlled ICON study that 48-week treatment of medically intractable chronic cluster headache (MICCH) with occipital nerve stimulation (ONS) is safe and effective. In L-ICON we prospectively evaluate its long-term effectiveness and safety.

METHODS

ICON participants were enrolled in L-ICON immediately after completing ICON. Therefore, earlier ICON participants could be followed longer than later ones. L-ICON inclusion was stopped after the last ICON participant was enrolled in L-ICON and followed for ≥2 years by completing six-monthly questionnaires on attack frequency, side effects, subjective improvement and whether they would recommend ONS to others. Primary outcome was the change in mean weekly attack frequency 2 years after completion of the ICON study compared to baseline. Missing values for log-transformed attack-frequency were imputed for up to 5 years of follow-up. Descriptive analyses are presented as (pooled) geometric or arithmetic means and 95% confidence intervals.

FINDINGS

Of 103 eligible participants, 88 (85%) gave informed consent and 73 (83%) were followed for ≥2 year, 61 (69%) ≥ 3 year, 33 (38%) ≥ 5 years and 3 (3%) ≥ 8.5 years. Mean (±SD) follow-up was 4.2 ± 2.2 years for a total of 370 person years (84% of potentially 442 years). The pooled geometric mean (95% CI) weekly attack frequency remained considerably lower after one (4.2; 2.8-6.3), two (5.1; 3.5-7.6) and five years (4.1; 3.0-5.5) compared to baseline (16.2; 14.4-18.3). Of the 49/88 (56%) ICON ≥50% responders, 35/49 (71%) retained this response and 15/39 (38%) ICON non-responders still became a ≥50% responder for at least half the follow-up period. Most participants (69/88; 78% [0.68-0.86]) reported a subjective improvement from baseline at last follow-up and 70/88 (81% [0.70-0.87]) would recommend ONS to others. Hardware-related surgery was required in 44/88 (50%) participants in 112/122 (92%) events (0.35 person-year-1 [0.28-0.41]). We didn't find predictive factors for effectiveness.

INTERPRETATION

ONS is a safe, well-tolerated and long-term effective treatment for MICCH.

FUNDING

The Netherlands Organisation for Scientific Research, the Dutch Ministry of Health, the NutsOhra Foundation from the Dutch Health Insurance Companies, and Medtronic.

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.

Minimally Invasive Preganglionic C2 Root Section for Occipital Neuralgia: 2 Case Reports and Operative Video

BACKGROUND

Occipital neuralgia is a painful condition that is believed to occur from processes that affect the greater, lesser, or third occipital nerves. Diagnosis is often made with a combination of classical symptoms, tenderness over the occipital region, and response to occipital nerve blocks. Cervical computed tomography or MRI may be obtained in multiple positions to detect any impingement. Diagnosis can be made with MRI tractography. Nonsurgical treatments include local anesthetic and steroid injections, anticonvulsant medications, botulinum toxin injections, physical therapy, acupuncture, transcutaneous electrical stimulation, cryoneurolysis, and radiofrequency ablation. Surgical treatments include greater occipital nerve decompression, C2 root section, intradural dorsal root rhizotomy, C1-2 fusion, and occipital nerve stimulation. Although stimulation has been favored in the past decade, complications and maintenance of the devices have led us to return to C2 ganglionectomy.

OBJECTIVE

To report on the use of a minimally invasive technique for C2 ganglionectomy to treat occipital neuralgia.

METHODS

Review demographic, surgery, and outcome data of a minimally invasive C2 root ganglionectomy used to treat to 2 patients with occipital neuralgia.

RESULTS

We report on 2 patients with clinically stereotypical unilateral occipital neuralgia confirmed by greater occipital nerve block, but with no imaging correlate. Both were successfully managed by C2 ganglionectomy through an 18-mm tubular retractor and outpatient surgery. Accompanying text, still photographs, and video describe the technique in detail.

CONCLUSION

Minimally invasive C2 ganglionectomy can be used to successfully treat occipital neuralgia.

Educational Curriculum for Peripheral Nerve Stimulation Developed by the North American Neuromodulation Society

BACKGROUND

Peripheral nerve stimulation (PNS) is an effective neuromodulation therapy for chronic neuropathic and nociceptive pain. Although the total number of PNS implantations has increased over the last decade, no curriculum exists to guide training and learning of this therapy. The goal of the North American Neuromodulation Society (NANS) education committee is to develop a series of competency-based curriculums for neuromodulation therapies. The PNS curriculum is the latest part of such series, following the curriculums for spinal cord stimulation and intrathecal drug delivery system.

MATERIALS AND METHODS

A multidisciplinary task force (anesthesiology, physical medicine and rehabilitation, neurosurgery, preventive medicine and public health, and neurology) was created by the educational committee of NANS to develop a PNS curriculum in accordance with the Accreditation Council for Graduate Medical Education (ACGME) milestones. The curriculum was created based on the best available evidence and expert knowledge (from our task force members) of available PNS systems. The final PNS curriculum was approved by the NANS board.

RESULTS

A PNS curriculum was developed by the task force. Milestones included professionalism, practice-based learning, interpersonal communication, medical knowledge, systems-based practice, procedural skills, and patient care. Each milestone was defined into three categories: early learner, advanced learner, and practitioner.

CONCLUSIONS

This manuscript provides a PNS training curriculum developed by a multidisciplinary task force of the NANS educational committee in accordance with the milestones described by ACGME for basic learners, advanced learners, and practitioners. This curriculum will help provide a structured training and evaluation process for obtaining proficiency in PNS treatment(s).

Occipital Nerve Stimulation: An Alternative Treatment of Chronic Migraine

PURPOSE OF REVIEW

This paper will examine the efficacy and safety of occipital nerve stimulation as a non-pharmacological alternative treatment for migraine.

RECENT FINDINGS

Migraine is characterized as a primary headache disorder with possible premonitory and aura phases, both of which vary greatly in symptomatology. The most common treatments for chronic migraine are pharmacological and are aimed at both acute relief (e.g., nonsteroidal anti-inflammatory drugs, triptans, and ergots) and prophylaxis (e.g., propranolol, valproic acid, and topiramate). For patients with medically refractory migraine, acute relief medication overuse can increase the risk of developing more severe and more frequent migraine attacks. Occipital nerve stimulation is a non-pharmacological alternative treatment for chronic migraine, which could eliminate the risk of adverse effects from acute relief medication overuse. Neurostimulation is thought to prevent pain by blocking signal transduction from small nociceptive fibers with non-painful signaling in larger adjacent fibers. Existing data from clinical trials support the overall safety and efficacy of occipital nerve stimulation for the treatment of chronic migraine. However, few large controlled, double-blinded studies have been conducted, due to both practical and ethical concerns. Currently, occipital nerve stimulation is available as an off-label use of neurostimulation for pain prevention but is not approved by the FDA specifically for the treatment of chronic migraine.

Safety and efficacy of occipital nerve stimulation for attack prevention in medically intractable chronic cluster headache (ICON): a randomised, double-blind, multicentre, phase 3, electrical dose-controlled trial

BACKGROUND

Occipital nerve stimulation (ONS) has shown promising results in small uncontrolled trials in patients with medically intractable chronic cluster headache (MICCH). We aimed to establish whether ONS could serve as an effective treatment for patients with MICCH.

METHODS

The ONS in MICCH (ICON) study is an investigator-initiated, international, multicentre, randomised, double-blind, phase 3, electrical dose-controlled clinical trial. The study took place at four hospitals in the Netherlands, one hospital in Belgium, one in Germany, and one in Hungary. After 12 weeks' baseline observation, patients with MICCH, at least four attacks per week, and history of being non-responsive to at least three standard preventive drugs, were randomly allocated (at a 1:1 ratio using a computer-generated permuted block) to 24 weeks of occipital nerve stimulation at either 100% or 30% of the individually determined range between paraesthesia threshold and near-discomfort (double-blind study phase). Because ONS causes paraesthesia, preventing masked comparison versus placebo, we compared high-intensity versus low-intensity ONS, which are hypothesised to cause similar paraesthesia, but with different efficacy. In weeks 25-48, participants received individually optimised open-label ONS. The primary outcome was the weekly mean attack frequency in weeks 21-24 compared with baseline across all patients and, if a decrease was shown, to show a group-wise difference. The trial is closed to recruitment (ClinicalTrials.gov NCT01151631).

FINDINGS

Patients were enrolled between Oct 12, 2010, and Dec 3, 2017. We enrolled 150 patients and randomly assigned 131 (87%) to treatment; 65 (50%) patients to 100% ONS and 66 (50%) to 30% ONS. One of the 66 patients assigned to 30% ONS was not implanted and was therefore excluded from the intention-to-treat analysis. Because the weekly mean attack frequencies at baseline were skewed (median 15·75; IQR 9·44 to 24·75) we used log transformation to analyse the data and medians to present the results. Median weekly mean attack frequencies in the total population decreased from baseline to 7·38 (2·50 to 18·50; p<0·0001) in weeks 21-24, a median change of -5·21 (-11·18 to -0·19; p<0·0001) attacks per week. In the 100% ONS stimulation group, mean attack frequency decreased from 17·58 (9·83 to 29·33) at baseline to 9·50 (3·00 to 21·25) at 21-24 weeks (median change from baseline -4·08, -11·92 to -0·25), and for the 30% ONS stimulation group, mean attack frequency decreased from 15·00 (9·25 to 22·33) to 6·75 (1·50 to 16·50; -6·50, -10·83 to -0·08). The difference in median weekly mean attack frequency between groups at the end of the masked phase in weeks 21-24 was -2·42 (95% CI -5·17 to 3·33). In the masked study phase, 129 adverse events occurred with 100% ONS and 95 occurred with 30% ONS. None of the adverse events was unexpected but 17 with 100% ONS and eight with 30% ONS were labelled as serious, given they required brief hospital admission for minor hardware-related issues. The most common adverse events were local pain, impaired wound healing, neck stiffness, and hardware damage.

INTERPRETATION

In patients with MICCH, both 100% ONS intensity and 30% ONS intensity substantially reduced attack frequency and were safe and well tolerated. Future research should focus on optimising stimulation protocols and disentangling the underlying mechanism of action.

FUNDING

The Netherlands Organisation for Scientific Research, the Dutch Ministry of Health, the NutsOhra Foundation from the Dutch Health Insurance Companies, and Medtronic.

An unusual case of lead migration in occipital nerve stimulation: A case report and literature review

Background:

Lead migration is a complication associated with occipital nerve stimulation (ONS). We present a rare case in which fibrosis in the stress relief loop caused lead migration in the treatment of occipital neuralgia.

Case Description:

A 30-year-old woman with a 5-year history of refractory occipital neuralgia, who had been under ONS therapy for 2 months, presented with a sudden onset of typical occipital neuralgia pain associated with cervical muscles spasms and myoclonus. A skull radiography showed lead migration. The patient underwent surgery for lead repositioning. During surgery, we identified extensive fibrosis throughout the stress relief loop that produced several constriction points. The fibrosis in the stress relief loop increased tension on the lead during head-and-neck movement, causing progressive migration of the lead.

Conclusion:

Although lead migration is a common complication of ONS, its association with fibrosis in the stress relief loop has not, to the best of our knowledge, been reported before. Lead migration can directly affect treatment outcome and it is, therefore, important to fully understand the possible mechanisms that can cause it and how to promptly manage them.

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.

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.

Peripheral Nerve Stimulation for Occipital Neuralgia

Background

Chronic headaches are the second most prevalent disease and second most common cause for years lived with disability worldwide. Occipital neuralgia can cause headaches or be present in addition to other more prevalent causes of headache. If these headaches fail to respond to conservative and pharmacological therapy, physicians proceed to more invasive treatments, starting with infiltration of the greater occipital nerve with local anesthetic with or without corticosteroids, followed by nerve ablation or stimulation. Occipital nerve stimulation gained more popularity as the technology improved and more pain physicians received training on interventional procedures.

Methods

In this manuscript, we are presenting our experience with ultrasound-guided implant of occipital nerve stimulators using peripheral nerve stimulator systems. After confirming appropriateness of treatment by a successful occipital nerve block (i.e., resulting in &gt;50% relief in patients’ pain intensity), we implanted five stimulator systems in three patients (two bilateral).

Results

We followed these patients for an average of eight months, and the average pain reduction was ∼50%. We did not observe any adverse events during or immediately after surgery. One patient developed an adverse reaction to the adhesive of the battery transmitter, but it was not severe enough to stop her from using the stimulator.

Conclusions

Considering the ease of implant and minimal side effects, implant of peripheral nerve stimulators to stimulate the occipital nerve is a promising treatment modality for patients with chronic headache who present with features of occipital neuralgia. However, wider use of this treatment modality is subject to further studies.

Complications and Effects of Dorsal Root Ganglion Stimulation in the Treatment of Chronic Neuropathic Pain: A Nationwide Cohort Study in Denmark

OBJECTIVES

Dorsal root ganglion (DRG) stimulation is a novel treatment of chronic neuropathic pain and has been shown to be efficacious across several case reports and randomized trials. However, long-term follow-up is limited, as are reports of complication rates. This study presents efficacy and complications for patients treated with DRG stimulation.

MATERIALS AND METHODS

We performed an observational, multicenter cohort study of all patients in Denmark implanted with FDA-approved DRG stimulation systems to treat chronic, neuropathic pain between 2014 and 2018. Follow-up period was one to three years.

RESULTS

Forty-three patients underwent trial DRG stimulation; 33 were subsequently fully implanted. Pain location: 58% lower extremity; 21% upper extremity; 21% thoracic/abdominal. At the end of the observation period, 58% of fully implanted patients were still implanted; 42% had fully functional systems. In these patients, average Numerical Rating Scale (NRS)-score of pain was reduced from 6.8 to 3.5 (p = 0.00049) and worst NRS-score was reduced from 8.6 to 6.0 (p = 0.0039) at 12 months follow-up. Pain Catastrophizing Score was reduced from 32 to 15 (p = 0.0039). Thirteen patients experienced complications related to defect leads (39% of implanted systems). In four patients (12%), lead removal left fragments in the root canal due to lead fracture, and three patients suffered permanent nerve damage during attempts to replace broken leads.

CONCLUSIONS

This study suggests a significant, clinically relevant effect of DRG stimulation on neuropathic pain, but also demonstrates substantial problems with maintenance and revision of currently available systems. Consequently, treatment with equipment marketed specifically for DRG stimulation is currently paused in Denmark.

Placement and Anchoring of Trigeminal Neurostimulation Electrodes: Technical Report

BACKGROUND

Peripheral neurostimulation (PNS) for medically refractory trigeminal and craniofacial pain is an emerging alternative to traditional surgical approaches. Technical problems with craniofacial PNS have included electrode migration and erosion, limiting the utility and cost-effectiveness of this procedure.

OBJECTIVE

To review our institutional surgical technique for trigeminal PNS implantation, focusing on a novel technique for electrode anchoring.

METHODS

Consecutive cases of permanent craniofacial PNS placement by a single surgeon over 36 months were reviewed for surgical technique and technical outcomes. Electrodes were placed percutaneously with open anchoring to the pericranium at a separate parietal incision.

RESULTS

Sixteen systems (53 electrodes) were implanted in 14 patients. Median follow-up was 13 months (range, 5-29 months). Electrode placement was successful in all cases with no intraoperative complications. There was 1 lead migration (6.3% per patient; 1.8% per lead) and no cases of erosion. Two patients (14.3%) required explant for infection, 1 of whom was successfully reimplanted. Three patients (21.4%) underwent surgical revision other than for infection.

CONCLUSIONS

We present an improved method for craniofacial PNS surgery which introduces a separate incision for electrode anchoring at the parietal boss. This technique simplifies the procedure and greatly reduces rates of erosion and migration, improving patient comfort and satisfaction.

Effectiveness of Neurostimulation Technologies for the Management of Chronic Pain: A Systematic Review

OBJECTIVES

To describe the state of the literature for clinical effectiveness of neurostimulation used for the management of chronic pain.

METHODS

A systematic review of spinal cord stimulation (SCS), peripheral nerve stimulation (PNS), peripheral nerve field stimulation (PNFS), and supraorbital transcutaneous electrical nerve stimulation in patients with cancer and noncancer chronic pain was conducted. MEDLINE, Embase, CINAHL, and the Cochrane CENTRAL Register of Controlled Trials were searched, using terms like "electrical stimulation therapy" and "pain management." Direction of effect, consistency across studies, and strength of evidence for effects of neurostimulation on chronic pain were narratively synthesized.

RESULTS

A total of 15 randomized controlled trials (RCTs) examining SCS, 7 RCTs examining PNS/PNFS, and 1 nonrandomized trial examining supraorbital transcutaneous electrical nerve stimulation (TENS) were included. In nine SCS studies, neurostimulation had positive effects on pain. In three studies, neurostimulation did not significantly reduce pain. For PNS/PNFS, five studies found improvements in pain offered by neurostimulation; pain outcomes were not reported in two studies. In the TENS study, neurostimulation reduced headaches per month and medication consumption. Overall, 21 studies were of low or unclear risk of bias, 4 were high risk of bias, and the TENS study was not appropriate for assessment using the Cochrane Risk of Bias tool.

CONCLUSIONS

A robust body of evidence examining SCS and PNS was identified. Only one study for PNFS and TENS was identified; both reported pain reductions. Generally, neurostimulation improved pain control. Future studies should examine the effectiveness of neurostimulation offered early in the trajectory of chronic pain.

Occipital Nerve Stimulation

Although the first publications on clinical use of peripheral nerve stimulation for the treatment of chronic pain came out in the mid-1960s, it took 10 years before this approach was used to stimulate the occipital nerves. The future for occipital nerve stimulation is likely to bring new indications, devices, stimulation paradigms, and a decrease in invasiveness. As experience increases, one may expect that occipital nerve stimulation will eventually gain regulatory approval for more indications, most likely for occipital neuralgia, migraines and cluster headaches. This process may require additional studies, at least for approval from the US Food and Drug Administration.

Lead fracture of peripheral nerve stimulator for brachial plexopathy -a case report

Peripheral nerve stimulation (PNS) is a useful treatment for chronic pain, but it can cause damage depending on its application site. Here, we describe the case of a 54-year-old man who underwent PNS for brachial plexopathy in 2015. One lead was implanted on the left medial cord to stimulate the medial antebrachial cutaneous nerve, and the other was implanted on the radial nerve to stimulate the posterior antebrachial cutaneous nerve. Both leads were inserted near the shoulder joint but did not cross it. Before PNS, the patient did not move his shoulder and elbow because of severe pain, but the treatment greatly alleviated this pain. Twenty months after the operation, both leads were fractured, and the severe pain returned. Repetitive motion near the joint was closely related to the lead fractures. In conclusion, large joints as the insertion sites of PNS leads should be avoided to prevent lead fractures.

Long-term follow up of intractable chronic short lasting unilateral neuralgiform headache disorders treated with occipital nerve stimulation

Background Occipital nerve stimulation is a potential treatment option for medically intractable short-lasting unilateral neuralgiform headache attacks. We present long-term outcomes in 31 patients with short-lasting unilateral neuralgiform headache attacks treated with occipital nerve stimulation in an uncontrolled open-label prospective study. Methods Thirty-one patients with intractable short-lasting unilateral neuralgiform headache attacks were treated with bilateral occipital nerve stimulation from 2007 to 2015. Data on attack characteristics, quality of life, disability and adverse events were collected. Primary endpoint was change in mean daily attack frequency at final follow-up. Results At a mean follow-up of 44.9 months (range 13-89) there was a 69% improvement in attack frequency with a response rate (defined as at least a 50% improvement in daily attack frequency) of 77%. Attack severity reduced by 4.7 points on the verbal rating scale and attack duration by a mean of 64%. Improvements were seen in headache-related disability and depression. Adverse event rates were favorable, with no electrode migration or erosion reported. Conclusion Occipital nerve stimulation appears to offer a safe and efficacious treatment for refractory short-lasting unilateral neuralgiform headache attacks with significant improvements sustained in the long term. The procedure has a low adverse event rate when conducted in highly specialised units.

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.

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.

Neurostimulation in the treatment of primary headaches

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

Invasive occipital nerve stimulation for refractory chronic cluster headache: what evolution at long-term? Strengths and weaknesses of the method

Background

Invasive Occipital Nerve Stimulation (iONS) is a costly technique which appears effective in drug-refractory chronic cluster headache (drCCH) management. Available data on long-term effectiveness and safety of iONS in this indication are scarce, though they could be useful to neurologists and patients in daily practice. The purpose of this short report is to discuss the very long-term outcome of a drCCH cohort, including adverse events.

Findings

Previously, favourable results were obtained with iONS in 15 drCCH patients: 80 % were significantly improved and 60 % were pain free. We report here the very long-term follow-up (up to nine years) of 10 patients belonging to this cohort. Meanwhile 5 patients had to be definitively explanted because of device infection (3) or paresthesia intolerance (2). Four patients (40 %) evolved to an episodic form of CH. Six remained chronic but their attack frequency was decreased by 70 % on average. Intake of preventive drugs is still necessary in 80 % of patients. All patients needed at least one battery replacement.

Conclusions

Up to nine years after implantation, iONS is still effective in most patients with drCCH. Concomitant preventive drugs remain often necessary. Forty percent of patients reverse to episodic CH, possibly by natural history. iONS is not a benign procedure but device-related complications appear similar to those reported with other invasive neurostimulators.

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.

Use of botulinum toxin injections to treat peripheral stimulator induced facial muscle twitching: a case report

Background

Facial pain can be a management challenge. Peripheral nerve/field stimulation may be an effective option for refractory cases, but direct muscle stimulation with facial twitching may result. Botulinum toxin injections have been used for blepharospasm and may be effective when facial stimulation results in unacceptable facial muscle twitching due to peripheral stimulation.

Case presentation

A 53-year old female suffered with chronic, refractory facial pain and migraines. Her facial pain began after a root canal of a left upper molar. She was trialed and then permanently implanted with a 1 × 8 sub-compact percutaneous stimulator lead, resulting in improved pain control and reduced medication use. However, she experienced blepharospasm whenever the amplitude was above 2.75 A. Therefore, she was treated with botulinum toxin injections into her bilateral cheek, face, temple and occiput. This treatment provided excellent relief of the facial spasms, allowing her to use her stimulator at high amplitudes, and thereby maximizing her pain relief. She received two subsequent treatments of botulinum toxin injections at 5-month intervals with similar results.

Conclusion

Peripheral nerve/field stimulation is being used for headaches and facial pain. An undesirable side effect of this emerging therapy is direct muscle stimulation. Botulinum toxin injections may be an effective treatment modality when stimulation techniques provide pain relief but also causes muscle twitching.

Occipital Nerve Stimulation for Migraine: A Systematic Review

Patients who suffer from migraines often report impaired quality of life. Occipital nerve stimulation (ONS) is a novel treatment modality for migraines, although few systematic reviews have evaluated whether this therapy is efficacious. The objective of this study was to evaluate the clinical efficacy and safety of ONS for treating migraine through a literature review. We performed a literature search to identify studies that investigated ONS for migraine treatment. Evidence levels of these studies were assessed by recommendations set by the University of Oxford Centre for Evidence-Based Medicine. Five randomized controlled trials, 4 retrospective studies, and one prospective study met the inclusion criteria. Results from the retrospective studies and case series indicated that ONS significantly reduced the pain intensity and the number of days with headache in patients with migraine. However, the evidence of ONS efficacy established by randomized controlled trials was limited. Improvement in the migraine disability assessment (MIDAS) score was more dramatic than improvement in the SF-36 score at follow-up. The mean complication incidence of ONS was 66% for the reviewed studies. Future clinical studies should optimize and standardize the ONS intervention process and identify the relationship among the surgical process, efficacy, and complications resulting from the procedure.