Functional connectivity between trigeminal and occipital nerves revealed by occipital nerve blockade and nociceptive blink reflexes

Cerebellar somatotopy of the trigemino-cervical complex during nociception

INTRODUCTION

The somatotopic organization of the human cerebellum processes somato-motoric input. Its role during pain perception for nociceptive input remains ambiguous. A standardized experimental trigeminal nociceptive input in functional imaging might clarify the role of the cerebellum in trigeminal nociception. Also of interest is the greater occipital nerve, which innervates the back of the head, and can influence the trigeminal perception due to functional coupling within the brainstem, forming the so-called trigemino-cervical complex.

METHODS

In our preregistered study (clinicaltrials.gov: NTC03999060), we stimulated the greater occipital as well as the three main branches of the trigeminal nerve during functional magnetic resonance imaging in two independent cohorts of young healthy volunteers without psychiatric, neurological or pain-related disorders to disentangle overlapping somatotopic cerebellar organization of the nerves innervating the human head.

RESULTS

We found a dominant effect of the first trigeminal branch in the cerebellum, underpinning its particular role for headache diseases, and somatotopic representations in bilateral cerebellar lobules I-IV, V, VIIb, VIIIa and Crus I as well as in the brainstem.

SIGNIFICANCE

The study expands the current knowledge on facial and head pain processing by the cerebellum and provides an initial somatotopic map of the trigemino-cervical complex in the human cerebellum with a predominant representation of the first trigeminal branch.

Review of craniofacial pain syndromes involving the greater occipital nerve: relevant anatomy, clinical findings, and interventional management

Craniofacial pain syndromes exhibit a high prevalence in the general population, with a subset of patients developing chronic pain that significantly impacts their quality of life and results in substantial disabilities. Anatomical and functional assessments of the greater occipital nerve (GON) have unveiled its implication in numerous craniofacial pain syndromes, notably through the trigeminal-cervical convergence complex. The pathophysiological involvement of the greater occipital nerve in craniofacial pain syndromes, coupled with its accessibility, designates it as the primary target for various interventional procedures in managing craniofacial pain syndromes. This educational review aims to describe multiple craniofacial pain syndromes, elucidate the role of GON in their pathophysiology, detail the relevant anatomy of the greater occipital nerve (including specific intervention sites), highlight the role of imaging in diagnosing craniofacial pain syndromes, and discuss various interventional procedures such as nerve infiltration, ablation, neuromodulation techniques, and surgeries. Imaging is essential in managing these patients, whether for diagnostic or therapeutic purposes. The utilization of image guidance has demonstrated an enhancement in reproducibility, as well as technical and clinical outcomes of interventional procedures. Studies have shown that interventional management of craniofacial pain is effective in treating occipital neuralgia, cervicogenic headaches, cluster headaches, trigeminal neuralgia, and chronic migraines, with a reported efficacy of 60-90% over a duration of 1-9 months. Repeated infiltrations, neuromodulation, or ablation may prove effective in selected cases. Therefore, reassessment of treatment response and efficacy during follow-up is imperative to guide further management and explore alternative treatment options. Optimal utilization of imaging, interventional techniques, and a multidisciplinary team, including radiologists, will ensure maximum benefit for these patients.

Transient side shift of cluster headache attacks after unilateral greater occipital nerve injection

Attacks of cluster headache (CH) are usually side-locked in most, but not all, patients. In a few patients, the side may alternate between or, rarely, within cluster episodes. We observed seven cases in whom the side of CH attacks temporarily shifted immediately or shortly after unilateral injection of the greater occipital nerve (GON) with corticosteroids. In five patients with previously side-locked CH attacks and in two patients with previously side-alternating CH attacks, a side shift for several weeks occurred immediately (N = 6) or shortly (N = 1) after GON injection. We concluded that unilateral GON injections might cause a transient side shift of CH attacks through inhibition of the ipsilateral hypothalamic attack generator causing relative overactivity of the contralateral side. The potential benefit of bilateral GON injection in patients who experienced a side shift after unilateral injection should be formally investigated.

Neural control of cerebral blood flow: scientific basis of scalp acupuncture in treating brain diseases

Scalp acupuncture (SA), as a modern acupuncture therapy in the treatment of brain diseases, especially for acute ischemic strokes, has accumulated a wealth of experience and tons of success cases, but the current hypothesized mechanisms of SA therapy still seem to lack significant scientific validity, which may not be conducive to its ultimate integration into mainstream medicine. This review explores a novel perspective about the mechanisms of SA in treating brain diseases based on its effects on cerebral blood flow (CBF). To date, abundant evidence has shown that CBF is significantly increased by stimulating specific SA points, areas or nerves innervating the scalp, which parallels the instant or long-term improvement of symptoms of brain diseases. Over time, the neural pathways that improve CBF by stimulating the trigeminal, the facial, and the cervical nerves have also been gradually revealed. In addition, the presence of the core SA points or areas frequently used for brain diseases can be rationally explained by the characteristics of nerve distribution, including nerve overlap or convergence in certain parts of the scalp. But such characteristics also suggest that the role of these SA points or areas is relatively specific and not due to a direct correspondence between the current hypothesized SA points, areas and the functional zones of the cerebral cortex. The above evidence chain indicates that the efficacy of SA in treating brain diseases, especially ischemic strokes, is mostly achieved by stimulating the scalp nerves, especially the trigeminal nerve to improve CBF. Of course, the mechanisms of SA in treating various brain diseases might be multifaceted. However, the authors believe that understanding the neural regulation of SA on CBF not only captures the main aspects of the mechanisms of SA therapy, but also facilitates the elucidation of other mechanisms, which may be of greater significance to further its clinical applications.

Management of cluster headache: Treatments and their mechanisms

BACKGROUND

The management of cluster headache is similar to that of other primary headache disorders and can be broadly divided into acute and preventive treatments. Acute treatments for cluster headache are primarily delivered via rapid, non-oral routes (such as inhalation, nasal, or subcutaneous) while preventives include a variety of unrelated treatments such as corticosteroids, verapamil, and galcanezumab. Neuromodulation is becoming an increasingly popular option, both non-invasively such as vagus nerve stimulation when medical treatment is contraindicated or side effects are intolerable, and invasively such as occipital nerve stimulation when medical treatment is ineffective. Clinically, this collection of treatment types provides a range of options for the informed clinician. Scientifically, this collection provides important insights into disease mechanisms.

METHODS

Two authors performed independent narrative reviews of the literature on guideline recommendations, clinical trials, real-world data, and mechanistic studies.

RESULTS

Cluster headache is treated with acute treatments, bridge treatments, and preventive treatments. Common first-line treatments include subcutaneous sumatriptan and high-flow oxygen as acute treatments, corticosteroids (oral or suboccipital injections) as bridge treatments, and verapamil as a preventive treatment. Some newer acute (non-invasive vagus nerve stimulation) and preventive (galcanezumab) treatments have excellent clinical trial data for episodic cluster headache, while other newer treatments (occipital nerve stimulation) have been specifically tested in treatment-refractory chronic cluster headache. Most treatments are suspected to act on the trigeminovascular system, the autonomic system, or the hypothalamus.

CONCLUSIONS

The first-line treatments have not changed in recent years, but new treatments have provided additional options for patients.

Evaluation and management of temporomandibular disorders. Part 1: an orthopedic physical therapy update on examination and clinical reasoning

Temporomandibular (TM) disorders afflict many people globally and, despite the presence of existing peer-reviewed material that assists conservative orthopedic providers, recent advances in knowledge indicate that updated resources are required for students, clinicians, and educators. This two-part series builds off previously published material to present newer supplementary information that can be useful during the evaluation and management processes. Content in Part 1 of this series includes a discussion about the factors that have been shown to contribute to TM disorders, an updated perspective of relevant pain science, a discussion of self-report outcome measures, and various different topics related to the examination of patients with TM disorders. Part 2 addresses information related to the temporomandibular joint disc, joint hypermobility, oral splints, and clinical reasoning. In combination with other available publications, this two-part series provides clinicians an opportunity to improve their delivery of effective and efficient clinical services for people diagnosed with TM disorders.

Greater occipital nerve block in the treatment of headaches. Review of evidence

INTRODUCTION

Peripheral nerve blocks have been a common treatment for multiple headaches. By far, the greater occipital nerve block is the most used and with the stronger body of evidence in routine clinical practice.

METHODS

We searched Pubmed Meta-Analysis/Systematic Review, in the last 10 years. Of these results, meta-analyses, and in the absence of these systematic reviews, assessing Greater Occipital Nerve Block in headache has been selected for review.

RESULTS

We identified 95 studies in Pubmed, 13 that met the inclusion criteria.

CONCLUSION

Greater occipital block is an effective and safe technique, easy to perform and which has shown its usefulness in migraine, cluster headache, cervicogenic headache and Post-dural puncture headache. However, more studies are needed to clarify its long-term efficacy, its place in clinical treatment, the possible difference between different anaesthetics, the most convenient dosage and the role of concomitant use of corticosteroids.

Peripheral nerve stimulation: A neuromodulation-based approach

Recent technological improvements have positioned us at the threshold of innovative discoveries that will assist in new perspectives and avenues of research. Increased attention has been directed towards peripheral nerve stimulation, particularly of the vagus, trigeminal, or greater occipital nerve, due to their unique pathway that engages neural circuits within networks involved in higher cognitive processes. Here, we question whether the effects of transcutaneous electrical stimulation are mediated by synergistic interactions of multiple neuromodulatory networks, considering this pathway is shared by more than one neuromodulatory system. By spotlighting this attractive transcutaneous pathway, this opinion piece aims to acknowledge the contributions of four vital neuromodulators and prompt researchers to consider them in future investigations or explanations.

Nerve blocks for occipital headaches: A systematic review and meta-analysis

Migraine surgeons have identified six "trigger sites" where cranial nerve compression may trigger a migraine. This study investigates the change in headache severity and frequency following nerve block of the occipital trigger site. This PRISMA-compliant systematic review of five databases searched from database inception through May 2020 is registered under the PROSPERO ID: CRD42020199369. Only randomized controlled trials utilizing injection treatments for headaches with pain or tenderness in the occipital scalp were included. Pain severity was scored from 0 to 10. Headache frequency was reported as days per week. Included were 12 RCTs treating 586 patients of mean ages ranging from 33.7 to 55.8 years. Meta-analyses of pain severity comparing nerve blocks to baseline showed statistically significant reductions of 2.88 points at 5 to 20 min, 3.74 points at 1 to 6 weeks, and 1.07 points at 12 to 24 weeks. Meta-analyses of pain severity of nerve blocks compared with treatment groups of neurolysis, pulsed radiofrequency, and botulinum toxin type A showed similar headache pain severity at 1 to 2 weeks, and inferior improvements compared with the treatment groups after 2 weeks. Meta-analyses of headache frequency showed statistically significant reductions at 1 to 6-week follow-ups as compared with baseline and at 1 to 6 weeks as compared with inactive control injections. The severity and frequency of occipital headaches are reduced following occipital nerve blocks. This improvement is used to predict the success of migraine surgery. Future research should investigate spinous process injections with longer follow-up.

OnabotulinumtoxinA: Still the Present for Chronic Migraine

OnabotulinumtoxinA (BT-A) is one of the few drugs approved for the preventive treatment of chronic migraine (CM). Despite this, some aspects of its mechanism of action are still a matter of debate, and the precise magnitude of BT-A effects needs to be completely elucidated. BT-A acts primarily upon trigeminal and cervical nerve endings, by inhibiting the release of inflammatory mediators such as calcitonin gene-related peptide, as well as reducing the insertion of ionotropic and metabotropic receptors into the neuronal membrane. These actions increase the depolarization threshold of trigeminal and cervical nerve fibers, thus reducing their activation. The central actions of BT-A are still a matter of debate: a retrograde axonal transport has been postulated, but not clearly assessed in humans. Clinically, the efficacy of BT-A in CM has been assessed by large, randomized placebo-controlled trials, such as the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials. Those results were also confirmed in a wide range of open-label studies, even for long-term periods. Recently, novel findings have led to a better understanding of its pharmacological actions and clinical usefulness in migraine prevention. This narrative review summarizes, updates and critically revises the available data on BT-A and its possible implementation in chronic migraine. Moreover, the current role of BT-A in CM treatment has been discussed.

An Investigation of temporomandibular pain, headache, and fatigue in relation with long-term mask use during the COVID-19 pandemic period

OBJECTIVE

To investigate the effects of long-term mask use on temporomandibular pain, headache, and fatigue during the COVID-19 pandemic period via a survey.

METHODS

The survey was sent online, and symptoms associated with mask use, perception of mask discomfort, temporomandibular dysfunction, fatigue, headache, and trigger points of temporomandibular joint were evaluated.

RESULTS

For the study, 909 people were screened. Head, neck, face, throat, ear, and jaw pain, cheek tension, teeth clamping, acne, mask trace, palpitation, and voice and sleep disorders were different between groups (p < 0.05). The individuals' temporomandibular dysfunction and fatigue were different between groups (p < 0.05).

CONCLUSION

Long-term mask use can cause many symptoms, such as headache, jaw pain, and fatigue. Furthermore, increased mask-wearing time can trigger all these symptoms. The authors recommend relaxing breaks and exercises for neck, jaw, and face muscles along with the use of appropriate masks to minimize negative symptoms.

The association between onabotulinumtoxinA and anti-CGRP monoclonal antibodies: a reliable option for the optimal treatment of chronic migraine

Chronic migraine (CM) is a great challenge for physicians dealing with headaches. Despite the introduction of the monoclonal antibodies (mAbs) acting against the calcitonin gene-related peptide (CGRP) that has revolutionized the treatment of CM, some patients still experience an incomplete relief. So, the association of two preventive treatments may be a reliable option for these patients. So, onabotulinumtoxinA (BT-A) and anti-CGRP mAbs may be used together, and some pre-clinical and clinical evidence of an additive action of the 2 drugs is emerging. In particular, since BT-A acts mainly on C-fibers and anti-CGRP mAbs on Aδ ones, their association may prevent the wearing-off phenomenon of BT-A, thus giving an additional benefit in those patients experiencing an incomplete response to BT-A alone. Despite this, the clinical studies available in the literature have a small sample size, often a retrospective design, and are heterogeneous in terms of the outcomes chosen. Considering this, the evidence of a favorable effect of the association between BT-A and anti-CGRP mAbs is still scarce. Furthermore, this association is explicitly forbidden by many National regulatory agencies, due to the high costs of both treatments. Anyway, their association could help in reducing the burden associated with the most severe cases of CM, thus relieving the direct and indirect costs of this condition. More well-designed studies with big samples are needed to unveil the real therapeutic gain of this association. Moreover, pharmacoeconomics studies should be performed, to assess the economic suitability of this association.

Outcomes of transcutaneous nerve stimulation for migraine headaches: a systematic review and meta-analysis

BACKGROUND

Implanted and transcutaneous nerve stimulators have shown promise as novel non-pharmacologic treatment for episodic and chronic migraines. The purpose of this study was to summarize the reported efficacy of transcutaneous single nerve stimulators in management of migraine frequency and severity.

METHODS

A systematic review of five databases identified studies treating migraines with transcutaneous stimulation of a single nerve. Random effects model meta-analyses were conducted to establish the effect of preventive transcutaneous nerve stimulation on headache days per month and 0-10 numeric rating scale pain severity of headaches for both individuals with episodic and chronic migraines.

RESULTS

Fourteen studies, which treated 995 patients, met inclusion criteria, including 7 randomized controlled trials and 7 uncontrolled clinical trials. Transcutaneous nerve stimulators reduced headache frequency in episodic migraines (2.81 fewer headache days per month, 95% CI 2.18-3.43, I² = 21%) and chronic migraines (2.97 fewer headache days per month, 95% CI 1.66-4.28, I² = 0%). Transcutaneous nerve stimulators reduced headache severity in episodic headaches (2.23 fewer pain scale points, 95% CI 1.64-2.81, I² = 88%).

CONCLUSIONS

Preventive use of transcutaneous nerve stimulators provided clinically significant reductions in headache frequency in individuals with chronic or episodic migraines. Individuals with episodic migraines also experienced a reduction in headache pain severity following preventive transcutaneous nerve stimulation.

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.

Comparison of the clinical efficacy of bilateral and unilateral GON blockade at the C2 level in chronic migraine

The main purpose of this study was to retrospectively compare the unilateral and bilateral application of proximal greater occipital nerve (GON) block at the C2 level in the treatment of chronic migraine disease. In chronic migraine patients who underwent GON blockade, the average number of migrainous painful days per month, the average duration of pain in attacks, the highest visual analogue scale (VAS) score in pain intensity for one month, and total analgesic use were recorded before and after the block. According to the GON block protocol applied by our clinic, the patients were treated for GON block 4 times a month, once a week. The data obtained were recorded before the treatment, in the 1st and 3rd months after the last injection, and the results were compared using the chi-square, Fisher, Mann-Whitney U, and Wilcoxon-signed rank tests. During the 3-month follow-up, the groups did not differ significantly in terms of the number of days with headache in 30 days, the average duration of headache, the highest VAS score in 30 days, and total analgesic use in 30 days. In both groups, the findings decreased in the 1st month and increased in the 3rd month compared to pre-treatment. However, results of both the 1st and 3rd months were significantly lower than pre-treatment (p<0.05), and there was a clinical benefit compared to pretreatment. While the GON block at the C2 level was effective in the treatment of chronic migraine, the superiority of bilateral application to unilateral application was not detected.

Greater Occipital Nerve Block with Local Anesthetics and Corticosteroids in Treatment-Resistant Chronic Migraine

Objective: We investigated the efficacy and tolerability of greater occipital nerve block with lidocaine plus betamethasone in adults with chronic migraine in whom two or more previous preventive treatments were unsuccessful. Methods: Ten participants were enrolled in a 24-weeks, randomized, double-blind, placebo-controlled, crossover trial conducted at a single tertiary headache center in Copenhagen (Denmark). After a 4-week run-in period, participants underwent treatment with bilateral greater occipital nerve block with lidocaine plus betamethasone (GONb) or lidocaine plus saline (placebo) with a 4-week interval wash-out phase between the 8-week crossover periods. The primary aim was to compare the number of migraine days during crossover periods after GONb or placebo. This trial is registered at ClinicalTrials.gov (NCT02686983). Results: This study was stopped before achieving the a priori sample size, due to a slow enrollment. Ten participants were recruited, completed the study and were included in the analyses. At the baseline, the mean number of monthly migraine days was 22.9 (range, 14-30). No difference between GONb and placebo on the reduction of monthly migraine days was observed (p = 0.147; 95% CI between 0.6 and 3.7 days). Adverse events were recorded in two patients after GONb, compared with three patients after placebo. Conclusions: GONb is not beneficial in patients with difficult-to-treat chronic migraine.

Treatment of chronic migraine and neck pain with cognitive-behavioral therapy. Case report

The article presents a case of a patient with chronic migraine, neck pain, drug-induced headache and generalized anxiety disorder. We analyzed the relationship between migraines and neck pain. The article discusses the interdisciplinary treatment of chronic migraine, which included educational conversation, detoxification therapy, rational relief of migraine attacks, preventive pharmacotherapy and cognitive-behavioral therapy. The latter allowed to change the patient's perception of the disease, reduce anxiety and catastrophization of pain, cope with fears, stop taking benzodiazepines, reduce the intake of pain relievers, and increase daily activity and productivity at work. Clinical efficacy (reduction in the frequency of headaches per month by 50% or more) was achieved after 3 months of treatment. Long-term (12 months) follow-up of the patient showed long-term clinical effect of the interdisciplinary treatment.

Experimental evidence of a functional relationship within the brainstem trigeminocervical complex in humans

ABSTRACT

The existence of a trigeminocervical complex (TCC) has been suggested based on animal data, but only indirect evidence exists in humans. We investigated the functional relationship between the trigeminal and the occipital region by stimulating one region and measuring electrical pain thresholds (EPTs) of the corresponding opposite region. This study consists of two single-blinded, randomized protocols. 40 healthy participants were recruited in the propaedeutic Protocol I. EPTs were measured on the V1 and the greater occipital nerve (GON) dermatome bilaterally as well as on the left forearm longitudinally before and after application of topical capsaicin. Protocol II was then online pre-registered and, additionally, the ipsilateral trigeminal dermatomes V2 and V3 were tested. GON stimulation increased the EPT ipsilateral at V1 after 20 minutes (p=0.006) compared to baseline, whereas trigeminal stimulation increased the EPT at the ipsilateral (p=0.023) as well as the contralateral GON (p=0.001) following capsaicin application. Protocol II confirmed these results and additionally showed that GON stimulation with capsaicin increased EPTs ipsilateral at all three trigeminal dermatomes and that trigeminal stimulation on V1 led to an ipsilateral increase of EPTs at GON, V2 and V3. Our data suggest a strong functional interplay between the trigeminal and occipital system in humans. The fact that stimulation of one of these dermatomes increases the electrical pain threshold of the respective other nerve could be explained by segmental inhibition on brainstem level.

Repeated greater occipital nerve injections with corticosteroids in medically intractable chronic cluster headache: a retrospective study

INTRODUCTION

Current prophylactic drugs for cluster headache are associated with limited efficacy, serious side effects and poor tolerability. Greater occipital nerve injection (GON-injection) has been proven effective and safe as a single, one-time injection in episodic (ECH), and to a lesser extent, chronic cluster headache (CCH). We aim to analyse the effectiveness and safety of repeated GON-injections in medically intractable chronic cluster headache (MICCH).

METHODS

Clinical data of all cluster headache patients who had received at least one GON-injection between 2014 and 2018 in our tertiary headache centre were retrieved from patients' medical records. Clinical history was taken as part of routine care shortly before and 6 weeks after GON-injection.

RESULTS

We identified 47 MICCH patients (79 injections), and compared results with 22 non-MI CCH patients (30 injections) and 50 ECH patients (63 injections). Nineteen MICCH patients received repeated injections (32 in total, range 2-8). Rates of clinical relevant improvement to a first injection were similar in all groups (MICCH: 60%, non-MICCH 73%, ECH 76%; attack freedom: MICCH: 30%, non-MICCH 32%, ECH 43%). Furthermore, no difference in response to the first and second injection was shown between groups (all p > 0.29). Median effect duration in MICCH was 6 weeks (IQR 2.8-12 weeks). Side effects were only mild and local.

CONCLUSION

In this retrospective analysis, first and repeated GON-injections were well-tolerated and equally effective in MICCH as in non-MICCH, and ECH.

Occipital Neuralgia and Its Management: An Overview

Background

Greater and lesser occipital neuralgias are primary neuralgias that are relatively uncommon, where the pain is felt in the distribution of these nerves.

Objective

This review paper was intended to describe the features and management of occipital neuralgia in the context of a challenging case.

Material and Methods

We looked at succinct literature from the past 30 years. We compared the features of our challenging case given in the current literature. In addition, an overview of the current literature is provided.

Results

The case, although proved to be a diagnostic challenge, we were able to reach a conclusion and render the patient almost complete pain relief by conservative management modalities. It proved to be a rare presentation of occipital neuralgia with unusual pain distribution, and we are able to describe a literature-based explanation for this entity to be a diagnostic and management challenge.

Conclusion

Primary headaches, i'n general, are a group of headache disorders that require exquisite diagnostic skills. The clinical history is a key factor when making an accurate diagnosis, and to establish an appropriate management plan.

Facemask headache: a new nosographic entity among healthcare providers in COVID-19 era

BACKGROUND

SARS-CoV-2 is a novel infectious agent causing coronavirus disease 2019, which has been declared as pandemic in March 2020. Personal protective equipment has been mandatory for healthcare workers in order to contain the outbreak of pandemic disease. Mild neurological disturbances such as headache have been related to the extensive utilization of facemask. This study aims to examine headache variations related to the intensive utilization of facemask among a cohort of healthcare professionals in a setting of low-medium risk of exposure to SARS-CoV-2.

METHODS

This is a cross-sectional study among healthcare providers from different hospital and clinics in Italy. Each participant completed a specifically designed self-administered questionnaire. Headache features and outcome measures' change from baseline were evaluated over a 4-month period, in which wearing facemask has become mandatory for Italian healthcare workers.

RESULTS

A total of 400 healthcare providers completed the questionnaire, 383 of them met the inclusion criteria. The majority were doctors, with a mean age of 33.4 ± 9.2 years old. Among 166/383 subjects, who were headache free at baseline, 44 (26.5%) developed de novo headache. Furthermore, 217/383 reported a previous diagnosis of primary headache disorder: 137 were affected by migraine and 80 had tension-type headache. A proportion (31.3%) of these primary headache sufferers experienced worsening of their pre-existing headache disorder, mainly for migraine frequency and attack mean duration.

CONCLUSIONS

Our data showed the appearance of de novo associated facemask headache in previous headache-free subjects and an exacerbation of pre-existing primary headache disorders, mostly experienced by people with migraine disease.

tDCS peripheral nerve stimulation: a neglected mode of action?

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation method widely used by neuroscientists and clinicians for research and therapeutic purposes. tDCS is currently under investigation as a treatment for a range of psychiatric disorders. Despite its popularity, a full understanding of tDCS's underlying neurophysiological mechanisms is still lacking. tDCS creates a weak electric field in the cerebral cortex which is generally assumed to cause the observed effects. Interestingly, as tDCS is applied directly on the skin, localized peripheral nerve endings are exposed to much higher electric field strengths than the underlying cortices. Yet, the potential contribution of peripheral mechanisms in causing tDCS's effects has never been systemically investigated. We hypothesize that tDCS induces arousal and vigilance through peripheral mechanisms. We suggest that this may involve peripherally-evoked activation of the ascending reticular activating system, in which norepinephrine is distributed throughout the brain by the locus coeruleus. Finally, we provide suggestions to improve tDCS experimental design beyond the standard sham control, such as topical anesthetics to block peripheral nerves and active controls to stimulate non-target areas. Broad adoption of these measures in all tDCS experiments could help disambiguate peripheral from true transcranial tDCS mechanisms.

Effect of occipitoatlantal decompression on cerebral blood flow dynamics as evaluated by Doppler ultrasonography

Context

Osteopathic manipulative treatment reduces symptoms in patients with headache disorders, but the underlying mechanisms are unclear.

Objective

To evaluate blood flow in the intracranial and extracranial vasculature before and after occipitoatlantal decompression (OAD) using Doppler ultrasonography.

Methods

Healthy, first-year osteopathic medical students from A.T. Still University's Kirksville College of Osteopathic Medicine participated in a randomized, single-blinded, two-period, two-treatment crossover study. The participants were randomly assigned to 1 of 2 treatment interventions: OAD or sham touch. After one week, participants returned to have the other intervention performed. Blood flow parameters-peak systolic velocity (PSV) and end-diastolic velocity (EDV)-in the middle cerebral artery (MCA), internal carotid artery (ICA), and vertebral artery (VA) were evaluated before, immediately after, 5 minutes after, and 10 minutes after treatment. Differences in PSV, EDV, heart rate (HR), and blood pressure (BP) for both interventions were analyzed for the four time points using mixed-effects models.

Results

Thirty healthy medical students (11 men, 19 women; mean age, 24 years) participated in this study. EDV increased after OAD in the MCA, ICA, and VA (all p<0.001); no change occurred after sham touch (all p>0.05). EDV was greater for all post-treatment timepoints after OAD in the MCA, ICA, and VA than after sham touch (all p<0.001). Although baseline PSV in the MCA measured before treatment was different between treatment interventions (p=0.01), no difference was found between interventions at any post-treatment time point (all p>0.59). Changes in PSV in the ICA and VA and for HR and BP did not depend on treatment intervention (p>0.06).

Conclusion

Increases in EDV occurred in major cranial arteries after OAD but not after sham touch, indicating that OAD improves blood flow to the brain. The exact mechanism of this increase is unknown; however, it can be explained by either parasympathetic stimulation through the secretion of vasodilating neurotransmitters or by a decrease in external tissue pressure on ICA and VA, with the resulting flow causing further dilation in the MCA.

Recent Advances in the Management of Cluster Headache

Purpose of review

Among the spectrum of pain conditions, cluster headache represents one of the most severe. Targeted therapies for cluster headache are evolving thus improving the available therapeutic armamentarium. A better understanding of the currently available therapies, as well as new and emerging options, may aide physicians to manage affected sufferers better by evolving treatment guidance.

Recent findings

While classic first-line medications are useful in some patients with cluster headache, they are often accompanied by significant side effects that limit their use. Recently, novel treatments with better tolerability and decreased medication interactions have proven to be effective. A remarkable example of this is the blockage of the calcitonin gene-related peptide pathway with monoclonal antibodies, which may be a key element in the future treatment of cluster headache. The sphenopalatine ganglion and vagus nerve perform a critical role in the regulation of pain and the trigeminal autonomic reflex. Neuromodulation therapies targeting these structures have shown excellent tolerability and few significant adverse events, constituting a promising form of treatment. Finally, several potential therapeutic targets are examined in this review, such as small molecule CGRP receptor antagonists, known as gepants, and serotonin receptor 5-HT1F receptor agonists: ditans.

Summary

In summary, a deepening of the understanding of cluster headache mechanisms in recent years has driven the evolution of sophisticated therapeutic approaches that could allow a new era in the treatment of this difficult condition.

Muscle endurance training of the neck triggers migraine attacks

BACKGROUND

Most migraine patients report neck pain as part of their migraine symptomatology, but it is unknown whether triggering neck pain would induce migraine attacks. Our aim was to assess the occurrence of headache and/or neck pain after an endurance test of the neck muscles among migraineurs and controls.

METHODS

Sixty-five patients with migraine and 32 headache-free participants underwent a manual examination of the cervical spine by an assessor blinded towards the diagnosis and were sub-classified according to the appearance or absence of neck pain. Subsequently, the endurance of the neck flexors and extensors was tested three times, in a random order. The maximum sustained duration was recorded and the test was terminated when the subject was unable to maintain the position or reported pain. On the day after the assessment, participants were asked to report the potential occurrence of headache or neck symptoms.

RESULTS

None of the controls reported headache after assessment, while migraine-like headache was reported by 42% of the patients with migraine (p < 0.001) after 15.8 h (SD: 10.0). Neck pain was more prevalent in migraineurs compared to controls (45% vs. 16%, p = 0.006). When considering the neck pain subtype, there were no differences among the three profiles regarding neck pain but participants with referred pain to the head reported a migraine attack more often (45%, p = 0.03).

CONCLUSION

Patients with migraine are more likely to report neck pain and migraine attacks following a neck muscle endurance test. Participants with neck pain referred to the head during manual examination had a greater prevalence of migraine attacks than those without or with only local pain.

J-A Barré’s historic article “On posterior cervical sympathetic syndrome”: A translation from French

Barré’s 1926 report “Sur un syndrome sympathique cervicale postérieure et sa cause fréquente: l’arthrite cervicale” is arguably the first description of what we now call cervicogenic headache. Barré’s contribution to the subject and significant insights, which have stood the test of time, are insufficiently recognised. This article is an English translation of Barré’s French original.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pulsed radiofrequency on the occipital nerve for treatment of short-lasting unilateral neuralgiform headache: A case report

Short-lasting unilateral neuralgiform headache (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing (SUNCT)/Short-lasting Unilateral Neuralgiform headache attacks with Autonomic Symptoms) is a trigeminal autonomic cephalalgia with difficult treatment and its management is based on neuromodulator drugs and sometimes ablative procedures on the trigeminal nerve. A positive response to occipital anesthetic blocks and peripheral and deep neurostimulation has also been described. We present the case of a patient with criteria of left SUNCT and transient response to occipital anesthetic blocks, satisfactorily controlled with pulsed radiofrequency (PRF) of the occipital nerve. Upon examination, the patient had tenderness in the left greater occipital nerve (GON). Blockade was performed with anesthetic and corticosteroid, obtaining a highly positive but transient response. After several nerve blocks, the patient was referred to the Pain Unit where pulsed radiofrequency on the left GON was performed. After two sessions, more than 90% of reduction of pain was achieved, maintained for 12 months. There haven’t been found data in the literature on the use of GON PRF for the treatment of SUNCT, while there are descriptions for other types of cranial pain. The intention of our case is to make this procedure to be considered as an alternative for the treatment of this entity in patients who respond to anesthetic blocks.

Ultrasound-Guided Pulsed Radiofrequency of C2 Dorsal Root Ganglion as Adjuvant Treatment for Chronic Headache Disorders: A Case Report

Cluster headaches are characterized by unilateral sudden onset of intense, brief, sharp pain along the side of the face around the eye. Patients often can have symptoms that are resistant to medications, nerve blocks, and surgical treatments. There is increasing evidence of anatomical and functional connections between the trigeminal and occipital nerves. We present a patient with cluster headache presenting with chronic ipsilateral facial pain with nasal congestion and left eye pain who achieved sustained pain relief with an ultrasound-guided injection into the pterygopalatine fossa in conjunction with an ultrasound-guided pulsed radiofrequency ablation procedure involving the C2 dorsal root ganglion.

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.

Nerve blocks in paediatric and adolescent headache disorders

PURPOSE OF REVIEW

Headaches in children and adolescents are common, causing debilitating symptoms in many. Treatment of headache disorders can be complex and standard lifestyle changes as well as oral medications may offer inadequate relief. The purpose of this article is to review the mechanism of action, efficacy and technique of peripheral nerve blocks (PNBs) and the role they play in treating paediatric headache disorders.

RECENT FINDINGS

Evidence for the use of PNBs in youth is limited. However, available studies show evidence of benefit in both primary and secondary headache disorders. Variability exists in the type of block, medication choice, volume infused and frequency of this treatment. There are no serious side effects associated with PNBs.

SUMMARY

PNBs are well tolerated and effective as adjunctive therapy for many disabling paediatric headache disorders. The technique can be easily learned by frontline and specialty practitioners. Prospective placebo-controlled studies are needed to determine how to best maximize PNBs for headache management (i.e. medication choice, timing and so on).

The effect of occipital nerve field stimulation on the descending pain pathway in patients with fibromyalgia: a water PET and EEG imaging study

Background

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood problems. Recently, occipital nerve field stimulation (ONS) has been proposed as an effective potential treatment for fibromyalgia-related pain. The aim of this study is to unravel the neural mechanism behind occipital nerve stimulation’s ability to suppress pain in fibromyalgia patients.

Materials and methods

Seven patients implanted with subcutaneous electrodes in the C2 dermatoma were enrolled for a Positron Emission Tomography (PET) H₂¹⁵O activation study. These seven patients were selected from a cohort of 40 patients who were part of a double blind, placebo-controlled study followed by an open label follow up at six months. The H₂¹⁵O PET scans were taken during both the “ON” (active stimulation) and “OFF” (stimulating device turned off) conditions. Electroencephalogram (EEG) data were also recorded for the implanted fibromyalgia patients during both the “ON” and “OFF” conditions.

Results

Relative to the “OFF” condition, ONS stimulation resulted in activation in the dorsal lateral prefrontal cortex, comprising the medial pain pathway, the ventral medial prefrontal cortex, and the bilateral anterior cingulate cortex as well as parahippocampal area, the latter two of which comprise the descending pain pathway. Relative deactivation was observed in the left somatosensory cortex, constituting the lateral pain pathway as well as other sensory areas such as the visual and auditory cortex. The EEG results also showed increased activity in the descending pain pathway. The pregenual anterior cingulate cortex extending into the ventral medial prefrontal cortex displayed this increase in the theta, alpha1, alpha2, beta1, and beta2 frequency bands.

Conclusion

PET shows that ONS exerts its effect via activation of the descending pain inhibitory pathway and the lateral pain pathway in fibromyalgia, while EEG shows activation of those cortical areas that could be responsible for descending inhibition system recruitment.

Trial Registration

This study is registered with ClinicalTrials.gov, number NCT00917176 (June 10, 2009).

Anatomical consideration of the occipital cutaneous nerves and artery for the safe treatment of occipital neuralgia

There is no standardized approach to the greater occipital nerve (GON) block technique for treating occipital neuralgia. The aim of the present study was to validate the previously-suggested guidelines for conventional injection techniques and to provide navigational guidelines for safe GON block. The GON, lesser occipital nerve (LON) and occipital artery (OA) were carefully dissected in the occipital region of embalmed cadavers. Using a 3 D digitizer, the GON, LON, and OA were observed on the two reference lines. The distances between the landmarks were recorded and statistically analyzed. On the superior nuchal line, the mean distances between the external occipital protuberance (EOP) and the most medial branch of the GON was 33.5 mm. The mean distance between the EOP and the most medial branch of the OA was 37.4 mm. On the EOP-mastoid process (MP) line, the GON was on the medial third and the LON the lateral third of the EOP-MP line. The safe injection points on the EOP-MP line are about 3 cm from the EOP, 1 cm inferior parallel to the EOP-MP line, and about 3 cm away from the MP. Clin. Anat. 31:1058-1064, 2018. © 2018 Wiley Periodicals, Inc.

The effectiveness of greater occipital nerve blockade in treating acute migraine-related headaches in emergency departments

OBJECTIVE

This study aimed to evaluate the effectiveness of a greater occipital nerve (GON) blockade against a placebo and classical treatments (non-steroidal anti-inflammatory drugs + metoclopramide) among patients who were admitted to the emergency department (ED) with acute migraine headaches.

METHOD

This prospective-randomized controlled study was conducted on patients with acute migraine headaches. The patients were randomly assigned to 3 treatment groups: the GON blockade group (nerve blockade with bupivacaine), the placebo group (injection of normal saline into the GON area), and the intravenous (IV) treatment group (IV dexketoprofen and metoclopramide). Sixty acute migraine attack patients were assigned to 3 groups of 20 patients each. The pain severity was assessed at 5, 15, 30, and 45 minutes with a 10-point pain scale score (PSS).

RESULTS

The mean decreases in the 5-, 15-, 30-, and 45-minutes PSS scores were greater in the GON blockade group than in the dexketoprofen and placebo groups. When comparing the 30- and 45-minutes PSS changes, a statistically significant difference was found among the 3 groups (P = .03 and P = .03, respectively).

CONCLUSION

A GON blockade was as effective as an IV dexketoprofen + metoclopramide treatment and superior to a placebo in patients with acute migraine headaches. Despite being an invasive procedure, a GON blockade might be an effective option for acute migraine treatment in the ED due to its rapid, easy, and safe application.

Regional anesthesia in pain management

PURPOSE OF REVIEW

The study focuses on neural blocks with local anesthetics in postoperative and chronic pain. It is prompted by the recent publication of several systematic reviews and guidelines.

RECENT FINDINGS

For postoperative pain, the current evidence supports infusions of local anesthetics at the surgical site, continuous peripheral nerve blocks, and neuraxial analgesia for major thoracic and abdominal procedures. Ultrasound guidance can improve the performance of the blocks and different patient outcomes, although the incidence of peripheral nerve damage is not decreased. For chronic pain, the best available evidence is on nerve blocks for the diagnosis of facet joint pain. Further research is needed to validate diagnostic nerve blocks for other indications. Therapeutic blocks with only local anesthetics (greater occipital nerve and sphenopalatine ganglion) are effective in headache. A possible mechanism is modulation of central nociceptive pathways. Therapeutic nerve blocks for other indications are mostly supported by retrospective studies and case series.

SUMMARY

Recent literature strongly supports the use of regional anesthesia for postoperative pain, whereby infusions at peripheral nerves and surgical site are gaining increasing importance. Local anesthetic blocks are valid for the diagnosis of facet joint pain and effective in treating headache. There is a need for further research in diagnostic and therapeutic blocks for chronic pain.

Anatomical basis for simultaneous block of greater and third occipital nerves, with an ultrasound-guided technique

PURPOSE

In some headache disorders, for which the greater occipital nerve block is partly effective, the third occipital nerve is also suggested to be involved. We aimed to establish a simple technique for simultaneously blocking the greater and third occipital nerves.

METHODS

We performed a detailed examination of dorsal neck anatomy in 33 formalin-fixed cadavers, and deduced two candidate target points for blocking both the greater and third occipital nerves. These target points were tested on three Thiel-fixed cadavers. We performed ultrasound-guided dye injections into these points, examined the results by dissection, and selected the most suitable injection point. Finally, this target point was tested in three healthy volunteers. We injected 4 ml of local anesthetic and 1 ml of radiopaque material at the selected point, guided with a standard ultrasound system. Then, the pattern of local anesthetic distribution was imaged with computed tomography.

RESULTS

We deduced that the most suitable injection point was the medial head of the semispinalis capitis muscle at the C1 level of the cervical vertebra. Both nerves entered this muscle, in close proximity, with little individual variation. In healthy volunteers, an anesthetic injected was confined to the muscle and induced anesthesia in the skin areas innervated by both nerves.

CONCLUSIONS

The medial head of the semispinalis capitis muscle is a suitable landmark for blocking the greater and third occipital nerves simultaneously, by which occipital nerve involvement in various headache disorders may be rapidly examined and treated.

Injection Therapy for Headache and Facial Pain

Peripheral nerve blocks are an increasingly viable treatment option for selected groups of headache patients, particularly those with intractable headache or facial pain. Greater occipital nerve block, the most widely used local anesthetic procedure in headache conditions, is particularly effective, safe, and easy to perform in the office. Adverse effects are few and infrequent. These procedures can result in rapid relief of pain and allodynia, and effects last for several weeks or months. Use of nerve block procedures and potentially onabotulinum toxin therapy should be expanded for patients with intractable headache disorders who may benefit, although more studies are needed for efficacy and clinical safety.