Botulinum Toxin a for Chronic Daily Headache: A Randomized, Placebo-Controlled, Parallel Design Study

Intramuscular Neural Distribution of the Gluteus Maximus Muscle: Diagnostic Electromyography and Injective Treatments

INTRODUCTION

The purpose of this study was to investigate neural patterns within the gluteus maximus (Gmax) muscle to identify optimal EMG placement and injection sites for botulinum toxin and other injectable agents.

METHODS

This study used 10 fixed and 1 non-fixed adult Korean cadavers. Intramuscular arborization patterns were confirmed in the cranial, middle, and caudal segments of 20 Gmax muscles using Sihler staining. Ultrasound images were obtained from one cadaver, and blue dye was injected using ultrasound guidance to confirm the results.

RESULTS

The intramuscular innervation pattern of the Gmax was mostly in the middle part of this muscle. The nerve endings of the Gmax are mainly located in the 40-70% range in the cranial segment, the 30-60% range in the middle segment, and the 40-70% range in the caudal segment.

DISCUSSION

Addressing the spasticity of the gluteus maximus requires precise, site-specific botulinum toxin injections. The use of EMG and other injection therapies should be guided by the findings of this study. We propose that these specific sites, which correspond to areas with the densest nerve branches, are the safest and most efficient locations for both botulinum toxin injections and EMG procedures.

Distribution of the intramuscular innervation of the triceps brachii: Clinical importance in the treatment of spasticity with botulinum neurotoxin

This study aimed to identify ideal sites for botulinum toxin injection by analyzing the intramuscular nerve patterns of the triceps brachii muscles. A modified Sihler's method was applied to the triceps brachii muscle (15 specimens), with long, medial, and lateral heads. The intramuscular arborization areas of the long, medial, and lateral heads of the triceps brachii muscle were measured as a percentage of the total distance from the midpoint of the olecranon (0%) to the anteroinferior point of the acromion (100%), by dividing the medial and lateral parts based on the line connecting the midpoint of the olecranon and the anteroinferior point of the acromion. Intramuscular arborization patterns were observed at the long head at two medial regions, proximally 30%-50% and distally 60%-70%; medial head of 30%-40%; and lateral head of 30%-60%. These results suggest that the treatment of spasticity of the triceps brachii muscles involves botulinum toxin injections in specific areas. The areas corresponding to the areas of maximum arborization are recommended as the most effective and safe points for botulinum toxin injection.

Safety of Onabotulinumtoxin A in Chronic Migraine: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Some 14% of global prevalence, based on high-income country populations, suffers from migraine. Chronic migraine is very disabling, being characterized by at least 15 headache days per month of which at least 8 days present the features of migraine. Onabotulinumtoxin A, targeting the machinery for exocytosis of neurotransmitters and neuropeptides, has been approved for use in chronic migraine since 2010. This systematic review and meta-analysis appraises the safety of onabotulinumtoxin A treatment for chronic migraine and the occurrence of treatment-related adverse events (TRAEs) in randomized, clinical studies in comparison with placebo or other comparators and preventative treatments according to the most updated Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 recommendations. The search retrieved 888 total records. Nine studies are included and seven were eligible for meta-analysis. The present study demonstrates that toxin produces more TRAEs than placebo, but less than oral topiramate, supporting the safety of onabotulinumtoxin A, and highlights the heterogeneity of the studies present in the literature (I² = 96%; p < 0.00001). This points to the need for further, adequately powered, randomized clinical trials assessing the safety of onabotulinumtoxin A in combination with the newest treatment options.

Assessment of the relative effectiveness of erenumab compared with onabotulinumtoxinA for the prevention of chronic migraine

OBJECTIVE

To assess the available clinical and economic evidence of erenumab vs onabotulinumtoxinA for chronic migraine (CM) and present de-novo indirect treatment comparisons (ITCs) based on available clinical trial data.

METHODS

We conducted ITCs based on results from the pivotal 295 trial (NCT02066415) of erenumab vs placebo and published aggregate data from the PREEMPT 1 (NCT00156910) and PREEMPT 2 (NCT00168428) trials of onabotulinumtoxinA vs placebo. ITCs were conducted for CM patients with and without prior administration of onabotulinumtoxinA and among CM patients with ≥3 prior preventive treatment failures. Efficacy was assessed based on responder rates of ≥50% reductions in monthly headache days (MHDs) and monthly migraine days (MMDs) as well as change from baseline in both MHDs and MMDs.

RESULTS

Among patients with CM, 140 mg erenumab was associated with a reduction of 1.2 MHD (p = .092) and a reduction of 1.0 MMD (p = .174) compared to onabotulinumtoxinA at Week 12. Among onabotulinumtoxinA-naïve patients, erenumab was associated with a reduction of 1.8 MHD (p = .026) and 1.4 MMD (p = .080) at Week 12. Among patients that had received ≥3 prior preventive treatments, the odds ratios comparing erenumab vs onabotulinumtoxinA were 1.7 for ≥50% responder rates based on reductions in MHD (p = .155) and 1.7 for ≥50% responder rates based on reductions in MMD (p = .140).

CONCLUSION

These findings suggest directional benefits (although not reaching the threshold of statistical significance) associated with erenumab vs onabotulinumtoxinA for the preventive treatment of CM. Evidence from this study may inform healthcare stakeholders in treatment selection and optimization for patients with CM.

Guidance to trigger point injection for treating myofascial pain syndrome: Intramuscular neural distribution of the quadratus lumborum

Postural habits and repetitive motion contribute toward the progress of myofascial pain by affecting overload on specific muscles, the quadratus lumborum (QL) muscle being the most frequently involved. The therapy of myofascial pain syndrome includes the release of myofascial pain syndrome using injective agents such as botulinum neurotoxin, lidocaine, steroids, and normal saline. However, an optimal injection point has not been established for the QL muscle. This study aimed to propose an optimal injection point for this muscle by studying its intramuscular neural distribution using the whole mount staining method. A modified Sihler's procedure was completed on 15 QL muscles to visualize the intramuscular arborization areas in terms of the inferior border of the 12th rib, the transverse processes of L1-L4, and the iliac crest. The intramuscular neural distribution of the QL had the densely arborized areas in the three lateral portions of L3-L4 and L4-L5 and the medial portion between L4 and L5.

Intramuscular Neural Distribution of the Serratus Anterior Muscle: Regarding Botulinum Neurotoxin Injection for Treating Myofascial Pain Syndrome

The serratus anterior muscle is commonly involved in myofascial pain syndrome and is treated with many different injective methods. Currently, there is no definite injection point for the muscle. This study provides a suggestion for injection points for the serratus anterior muscle considering the intramuscular neural distribution using the whole-mount staining method. A modified Sihler method was applied to the serratus anterior muscles (15 specimens). The intramuscular arborization areas were identified in terms of the anterior (100%), middle (50%), and posterior axillary line (0%), and from the first to the ninth ribs. The intramuscular neural distribution for the serratus anterior muscle had the largest arborization patterns in the fifth to the ninth rib portion of between 50% and 70%, and the first to the fourth rib portion had between 20% and 40%. These intramuscular neural distribution-based injection sites are in relation to the external anatomical line for the frequently injected muscles to facilitate the efficiency of botulinum neurotoxin injections. Lastly, the intramuscular neural distribution of serratus anterior muscle should be considered in order to practice more accurately without the harmful side effects of trigger-point injections and botulinum neurotoxin injections.

Anatomical locations of the motor endplates of sartorius muscle for botulinum toxin injections in treatment of muscle spasticity

PURPOSE

This study aimed to detect the idyllic locations for botulinum neurotoxin injection by analyzing the intramuscular neural distributions of the sartorius muscles.

METHODS

An altered Sihler's staining was conducted on sartorius muscles (15 specimens). The nerve entry points and intramuscular arborization areas were measured as a percentage of the total distance from the most prominent point of the anterior superior iliac spine (0%) to the medial femoral epicondyle (100%).

RESULTS

Intramuscular neural distribution were densely detected at 20-40% and 60-80% for the sartorius muscles. The result suggests that the treatment of sartorius muscle spasticity requires botulinum neurotoxin injections in particular locations.

CONCLUSIONS

These locations, corresponding to the locations of maximum arborization, are suggested as the most suggestive points for botulinum neurotoxin injection.

Calcitonin Gene-Related Peptide Monoclonal Antibodies Versus Botulinum Neurotoxin a in the Preventive Treatment of Chronic Migraine: An Adjusted Indirect Treatment Comparison Meta-Analysis

Purpose: Calcitonin gene-related peptide monoclonal antibodies (CGRPmAbs) are new agents approved by the US Food and Drug Administration for preventive treatment of chronic migraine. Comparison between CGRPmAbs and previously approved Botulinum neurotoxin A (BoNT-A) will inform optimal preventive treatment of chronic migraine, but head-to-head trials are lacking. We therefore aimed to perform adjusted indirect comparison between CGRPmAbs and BoNT-A through a meta-analysis.

Methods: OVID MEDLINE, EMBASE and the Cochrane central register of controlled trials, clinical registries, and government websites were searched from inception to September 2019. Randomized controlled trials comparing CGRPmAbs or BoNT-A with placebo in the preventive treatment of chronic migraine were included. The primary outcomes were headache days and migraine days measured at week 12. Data were synthesized by using a frequentist approach; and the treatments were ranked by P-score.

Results: We included 10 trials (n = 4,678) after screening 1049 candidates. Six trials were with low risk of bias. Fremanezumab had an effect similar to BoNT-A in the reduction of headache days at week 12 (standard mean difference [SMD] 0.08, 95%CI -0.55 to -0.7). Galcanezumab reduced more migraine days than BoNT-A at week 12 (SMD, -0.94, 95%CI −1.24 to −0.63); fremanezumab showed similar findings (SMD, −0.55, 95%CI −0.85 to −0.24). Galcanezumab and fremanezumab had better effect in mitigating headache impact at week 12. CGRPmAbs and BoNT-A had similar adverse event rate.

Conclusion: CGRPmAbs and BoNT-A had similar effect in the preventive treatment of chronic migraine. BoNT-A might be preferentially selected owing to its cost-effectiveness profiles. Further studies with direct comparison of the two treatments are warranted.

Topiramate, acupuncture, and BoNT-A for chronic migraine: a network meta-analysis

BACKGROUND

Botulinum neurotoxin A (BoNT-A) was the primary choice for preventive treatment of chronic migraine. Topiramate and acupuncture showed promising effect for chronic migraine, but their effectiveness relative to BoNT-A was rarely studied. We aimed to perform a network meta-analysis to compare the effectiveness and acceptability between topiramate, acupuncture, and BoNT-A.

METHODS

We searched OVID Medline, Embase, the Cochrane register of controlled trials (CENTRAL), the Chinese Clinical Trial Register, and clinicaltrials.gov for randomized controlled trials (RCTs) that compared topiramate, acupuncture, and BoNT-A with any of them or placebo in the preventive treatment of chronic migraine. A network meta-analysis was performed by using a frequentist approach and a random-effects model. The primary outcomes were reduction in monthly headache days and monthly migraine days at week 12. Acceptability was defined as the number of dropouts owing to adverse events.

RESULTS

We included 15 RCTs (n = 2545). Eleven RCTs were at low risk of bias. The network meta-analyses (n = 2061) showed that acupuncture (2061 participants; standardized mean difference [SMD] -1.61, 95% CI: -2.35 to -0.87) and topiramate (582 participants; SMD -0.4, 95% CI: -0.75 to -0.04) ranked the most effective in the reduction of monthly headache days and migraine days, respectively; but they were not significantly superior over BoNT-A. Topiramate caused the most treatment-related adverse events and the highest rate of dropouts owing to adverse events.

CONCLUSIONS

Topiramate and acupuncture were not superior over BoNT-A; BoNT-A was still the primary preventive treatment of chronic migraine. Large-scale RCTs with direct comparison of these three treatments are warranted to verified the findings.

Guidelines for botulinum neurotoxin injections in piriformis syndrome

BACKGROUND

The piriformis muscle is normally involved in piriformis syndrome and can be treated with botulinum neurotoxin using several different injection methods. However, definitive injection guidelines for the muscle have not been reported previously.

AIMS

This study aimed to determine the ideal area for injections based on the intramuscular nerve distribution as obtained using a modified Sihler's staining technique.

MATERIALS AND METHODS

A modified Sihler's method was applied to the piriformis muscle in 15 specimens. The intramuscular arborization areas were identified based on two anatomical landmarks: (a) the lateral border of the sacrum bone and (b) the greater trochanter.

RESULTS

The nerve entry point for both piriformis muscles was found in the area between the lateral border of the sacrum and one-fifth of the distance toward the greater trochanter. The intramuscular nerve distribution for the piriformis muscle had the largest arborization patterns between one-fifth and two-fifths of the distance from the sacrum to the greater trochanter. The piriformis muscle was tendinous from two-fifths of the distance to the greater trochanter.

DISCUSSION

This study has yielded suggested optimal injection locations for the piriformis muscle relative to external anatomical landmarks.

CONCLUSION

Clinicians can use these guidelines to ensure the effectiveness of not only botulinum neurotoxin injections but also other agents such as steroids, anesthetics, and normal saline. These guidelines will also help to avoid adverse outcomes of injection treatments.

Anatomical guide for botulinum neurotoxin injection: Application to cosmetic shoulder contouring, pain syndromes, and cervical dystonia

INTRODUCTION

This study proposes an ideal botulinum toxin injection point of the trapezius muscle for shoulder line contouring, pain management, and functional impairment. This study describes the intramuscular nerve branching in the trapezius muscle, providing essential information for botulinum neurotoxin injection.

METHOD

A modified Sihler's method was performed on the trapezius muscles (16 specimens). The intramuscular arborization areas were elucidated regarding the external occipital protuberance superiorly, spinous process of the 12th thoracic vertebra inferiorly and acromion of the scapula.

RESULT

The intramuscular neural distribution for the superior, middle, and inferior regions of the trapezius muscle had the greatest arborized patterns in the horizontal 1/5-2/5 and vertical 2/10-4/10 sections, the horizontal 1/5-3/5 and vertical 4/10-5/10 sections, and the horizontal 1/5-2/5 and vertical 5/10-7/10 sections, respectively.

DISCUSSION

We propose that BoNT treatments should be directed to the horizontal 1/5-2/5 and vertical 2/10-4/10 sections of the superior trapezius, the horizontal 1/5-3/5 and vertical 4/10-5/10 sections of the middle trapezius and the horizontal 1/5-2/5 and vertical 5/10-7/10 sections of the inferior trapezius. Additionally, injective treatment at the horizontal 2/5-3/5 and vertical 2/10-4/10 nerve entry points should be avoided to prevent nerve trunk damage causing paralysis. According to our guidelines, clinicians can ensure minimal dose injections and fewer adverse effects in botulinum neurotoxin injective treatment.

Entrapment Neuropathy: A Concept for Pathogenesis and Treatment of Headaches-A Narrative Review

Entrapment neuropathy is a known cause of neurological disorders. In the head and neck area, this pathophysiological mechanism could be a trigger for headache. Over the last few decades, injection of botulinum toxin type A in the muscles that are causing the compression as well as surgical decompression have proved to be effective treatment methods worldwide for large numbers of patients with daily headaches. In particular the entrapment of the supraorbital nerves in the glabellar musculature and the occipital nerves in the neck musculature are triggers for headache disorders for which many patients are still seeking an effective treatment. This article reviews the literature and aims to bring the concept of neural entrapment to the attention of a wider audience. By doing so, we hope to give more exposure to an effective and relatively safe headache treatment.

Botulinum toxins for the prevention of migraine in adults

BACKGROUND

Migraine occurs in around 15% of adults and is ranked as the seventh most disabling disease amongst all diseases globally. Despite the available treatments many people suffer prolonged and frequent attacks which have a major impact on their quality of life. Chronic migraine is defined as 15 or more days of headache per month, at least eight of those days being migraine. People with episodic migraine have fewer than 15 headache days per month. Botulinum toxin type A has been licensed in some countries for chronic migraine treatment, due to the results of just two trials.

OBJECTIVES

To assess the effects of botulinum toxins versus placebo or active treatment for the prevention or reduction in frequency of chronic or episodic migraine in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE & MEDLINE in Process, Embase, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry (to December 2017). We examined reference lists and carried out citation searches on key publications. We sent correspondence to major manufacturers of botulinum toxin.

SELECTION CRITERIA

Randomised, double-blind, controlled trials of botulinum toxin (any sero-type) injections into the head and neck for prophylaxis of chronic or episodic migraine in adults. Eligible comparators were placebo, alternative prophylactic agent or different dose of botulinum toxin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. For continuous outcomes we used mean change data when available. For dichotomous data we calculated risk ratios (RRs). We used data from the 12-week post-treatment follow-up time point. We assessed the evidence using GRADE and created two 'Summary of findings' tables.

MAIN RESULTS

Description of trialsWe found 90 articles describing 28 trials (4190 participants), which were eligible for inclusion. The longest treatment duration was three rounds of injections with three months between treatments, so we could not analyse long-term effects. For the primary analyses, we pooled data from both chronic and episodic participant populations. Where possible, we also separated data into chronic migraine, episodic migraine and 'mixed group' classification subgroups. Most trials (21 out of 28) were small (fewer than 50 participants per trial arm). The risk of bias for included trials was low or unclear across most domains, with some trials reporting a high risk of bias for incomplete outcome data and selective outcome reporting.Botulinum toxin versus placeboTwenty-three trials compared botulinum toxin with placebo. Botulinum toxin may reduce the number of migraine days per month in the chronic migraine population by 3.1 days (95% confidence interval (CI) -4.7 to -1.4, 4 trials, 1497 participants, low-quality evidence). This was reduced to -2 days (95% CI -2.8 to -1.1, 2 trials, 1384 participants; moderate-quality evidence) when we removed small trials.A single trial of people with episodic migraine (N = 418) showed no difference between groups for this outcome measure (P = 0.49).In the chronic migraine population, botulinum toxin reduces the number of headache days per month by 1.9 days (95% CI -2.7 to -1.0, 2 trials, 1384 participants, high-quality evidence). We did not find evidence of a difference in the number of migraine attacks for both chronic and episodic migraine participants (6 trials, N = 2004, P = 0.30, low-quality evidence). For the population of both chronic and episodic migraine participants a reduction in severity of migraine rated during clinical visits, on a 10 cm visual analogue scale (VAS) of 3.3 cm (95% CI -4.2 to -2.5, very low-quality evidence) in favour of botulinum toxin treatment came from four small trials (N = 209); better reporting of this outcome measure from the additional eight trials that recorded it may have improved our confidence in the pooled estimate. Global assessment and quality-of-life measures were poorly reported and it was not possible to carry out statistical analysis of these outcome measures. Analysis of adverse events showed an increase in the risk ratio with treatment with botulinum toxin over placebo 30% (RR 1.28, 95% CI 1.12 to 1.47, moderate-quality evidence). For every 100 participants 60 experienced an adverse event in the botulinum toxin group compared with 47 in the placebo group.Botulinum toxin versus other prophylactic agentThree trials studied comparisons with alternative oral prophylactic medications. Meta-analyses were not possible for number of migraine days, number of headache days or number of migraine attacks due to insufficient data, but individually trials reported no differences between groups for a variety of efficacy measures in the population of both chronic and episodic migraine participants. The global impression of disease measured using Migraine Disability Assessment (MIDAS) scores were reported from two trials that showed no difference between groups. Compared with oral treatments, botulinum toxin showed no between-group difference in the risk of adverse events (2 trials, N = 114, very low-quality evidence). The relative risk reduction (RRR) for withdrawing from botulinum toxin due to adverse events compared with the alternative prophylactic agent was 72% (P = 0.02, 2 trials, N = 119).Dosing trialsThere were insufficient data available for the comparison of different doses.Quality of the evidenceThe quality of the evidence assessed using GRADE methods was varied but mostly very low; the quality of the evidence for the placebo and active control comparisons was low and very low, respectively for the primary outcome measure. Small trial size, high risk of bias and unexplained heterogeneity were common reasons for downgrading the quality of the evidence.

AUTHORS' CONCLUSIONS

In chronic migraine, botulinum toxin type A may reduce the number of migraine days per month by 2 days compared with placebo treatment. Non-serious adverse events were probably experienced by 60/100 participants in the treated group compared with 47/100 in the placebo group. For people with episodic migraine, we remain uncertain whether or not this treatment is effective because the quality of this limited evidence is very low. Better reporting of outcome measures in published trials would provide a more complete evidence base on which to draw conclusions.

Current Prophylactic Medications for Migraine and Their Potential Mechanisms of Action

A relatively high number of different medications is currently used for migraine prevention in clinical practice. Although these compounds were initially developed for other indications and differ in their mechanisms of action, some general themes can be identified from the mechanisms at play. Efficacious preventive drugs seem to either suppress excitatory nervous signaling via sodium and/or calcium receptors, facilitate GABAergic inhibition, reduce neuronal sensitization, block cortical spreading depression and/or reduce circulating levels of CGRP. We here review such mechanisms for the different compounds.

Botulinum toxin in the management of chronic migraine: clinical evidence and experience

Chronic migraine (CM) is a severely disabling neurological condition characterized by episodes of pulsating unilateral or bilateral headache. The United States Food and Drug Administration (FDA) approved onabotulinumtoxinA (Botox®) for the prophylactic treatment of CM in 2010. It has been shown that onabotulinumtoxinA is effective in the reduction of headache frequency and severity in patients with CM. Treatment is well tolerated by the patients. This review reports on the history of botulinum neurotoxin (BoNT) in CM and presents the current clinical evidence for the use of onabotulinumtoxinA in the treatment of CM.

Contribution of intravestibular sensory conflict to motion sickness and dizziness in migraine disorders

Migraine is associated with enhanced motion sickness susceptibility and can cause episodic vertigo [vestibular migraine (VM)], but the mechanisms relating migraine to these vestibular symptoms remain uncertain. We tested the hypothesis that the central integration of rotational cues (from the semicircular canals) and gravitational cues (from the otolith organs) is abnormal in migraine patients. A postrotational tilt paradigm generated a conflict between canal cues (which indicate the head is rotating) and otolith cues (which indicate the head is tilted and stationary), and eye movements were measured to quantify two behaviors that are thought to minimize this conflict: suppression and reorientation of the central angular velocity signal, evidenced by attenuation ("dumping") of the vestibuloocular reflex and shifting of the rotational axis of the vestibuloocular reflex toward the earth vertical. We found that normal and migraine subjects, but not VM patients, displayed an inverse correlation between the extent of dumping and the size of the axis shift such that the net "conflict resolution" mediated through these two mechanisms approached an optimal value and that the residual sensory conflict in VM patients (but not migraine or normal subjects) correlated with motion sickness susceptibility. Our findings suggest that the brain normally controls the dynamic and spatial characteristics of central vestibular signals to minimize intravestibular sensory conflict and that this process is disrupted in VM, which may be responsible for the enhance motion intolerance and episodic vertigo that characterize this disorder.

Abnormal Tilt Perception During Centrifugation in Patients with Vestibular Migraine

Vestibular migraine (VM), defined as vestibular symptoms caused by migraine mechanisms, is very common but poorly understood. Because dizziness is often provoked in VM patients when the semicircular canals and otolith organs are stimulated concurrently (e.g., tilting the head relative to gravity), we measured tilt perception and eye movements in patients with VM and in migraine and normal control subjects during fixed-radius centrifugation, a paradigm that simultaneously modulates afferent signals from the semicircular canals and otoliths organs. Twenty-four patients (8 in each category) were tested with a motion paradigm that generated an inter-aural centrifugal force of 0.36 G, resulting in a 20° tilt of the gravito-inertial force in the roll plane. We found that percepts of roll tilt developed slower in VM patients than in the two control groups, but that eye movement responses, including the shift in the eye's rotational axis, were equivalent in all three groups. These results demonstrate a change in vestibular perception in VM that is unaccompanied by changes in vestibular-mediated eye movements and suggest that either the brain's integration of canal and otolith signals or the dynamics of otolith responses are aberrant in patients with VM.

OnabotulinumtoxinA for chronic migraine: a critical appraisal

Chronic migraine (CM) is a severe disabling condition with a few available evidence-based management options. OnabotulinumtoxinA (onaBoNTA) is approved for use in a number of disorders. Its benefits and potential use in migraine were observed incidentally while treating patients cosmetically for wrinkles. The mechanism of action of onaBoNTA in CM is not fully understood, but there is evidence that this involves axonal transport via sensory fibers. The Phase III REsearch Evaluating Migraine Prophylaxis Therapy trials have established the efficacy as well as the long-term safety and tolerability of onaBoNTA in CM. This review will discuss the evidence behind its use in this setting.

Medication-overuse headache in China: clinical profile, and an evaluation of the ICHD-3 beta diagnostic criteria

BACKGROUND

Although medication-overuse headache (MOH) is common in China, its clinical profile is not yet fully established. Meanwhile, ICHD-3 beta has been published, but its diagnostic criteria require further validation.

METHODS

We retrospectively classified the clinical features of 240 consecutive patients with MOH (55 males, 185 females), whose demographic data, headache features, overused medications (type, quantity, frequency and duration of use), headache-attributed burden, and outcomes were reviewed. We then applied the criteria of the several versions of ICHD (II, IIR and 3-beta) to these patients.

RESULTS

Compared with those with other headaches, patients with MOH were more likely to be less well educated (64.6% vs 42.0% for secondary school or lower, p < 0.0001), and on lower annual incomes (72.3% vs 56.0% for an income of Chinese yuan (CNY) 30,000 or less, p < 0.0001). Combination analgesics were the most commonly overused medications, and, caffeine (89.9%), aminopyrine (70.0%), phenacetin (53.9%) and phenobarbital (48.8%) were the most commonly used specific components of these. Only two patients (0.8%) had previously been given the diagnosis of MOH; accordingly, the median time to diagnosis after the estimated onset of the disorder was 4.0 years. The majority of patients (83.7%) improved with treatment. All 240 patients fulfilled the diagnostic criteria for MOH according to ICHD-3 beta; only 134 (55.8%) satisfied the diagnostic criteria for definite MOH according to ICHD-II, while 195 (81.2%) met those of ICHD-IIR.

CONCLUSIONS

MOH in China is associated with lower educational level and annual income. MOH has rarely been diagnosed and correctly treated in China. ICHD-3 beta appears to be more appropriate for the diagnosis of MOH than previous versions.

OnabotulinumtoxinA for the treatment of headache

Botulinum toxin, a potent muscle relaxant, has been found to have analgesic effects in patients with various pain syndromes. Both in vitro and in vivo studies showed the ability of the toxin to block the release of pain neurotransmitters, such as substance P, glutamate, and calcitonin gene-related peptide. The effect of the toxin, and specifically of one of its serotypes, botulinum neurotoxin type A, on headaches, has been extensively studied. This serotype is available in the United States in 3 forms, including as onabotulinumtoxinA. Data from clinical trials confirmed the efficacy, safety, and tolerability of onabotulinumtoxinA in the prophylactic treatment of chronic migraine, the most severe and debilitating type of migraine, in adults. The drug was approved by the Food and Drug Administration for this indication in 2010. The drug was not found to be effective for episodic migraine or tension-type headache. Noncontrolled studies suggest the efficacy of the toxin for headache associated with craniocervical dystonia. Proper injection technique and appropriate patient selection are essential for achieving positive results after treatment with onabotulinumtoxinA. The recommended injection paradigm combines a fixed site/fixed dose and follow the pain approaches, with the toxin injected to multiple sites of the head and neck, at a total dose of 155U-195U. The treatment is given at intervals of 12 weeks on average. The efficacy of onabotulinumtoxinA for some headaches, its long duration of action, and its favorable adverse effect profile make it a viable treatment option for the appropriate headache patients. The drug may be particularly suitable for patients who cannot tolerate, or are not compliant with, the daily intake of oral headache preventive drugs.

Do botulinum toxins have a role in the management of neuropathic pain?: a focused review

Botulinum neurotoxin (BoNT) is usually used in physiatric practice in the treatment of spasticity and dystonia. Research involving both animal and human subjects has emerged suggesting potential benefits in painful neuropathic conditions. The animal data strongly support the use of BoNT in the treatment of sensitized pain states. BoNT is probably effective at treating postherpetic neuralgia, probably or possibly effective at treating postoperative/posttraumatic neuropathic pain, and probably effective at treating painful diabetic neuropathy. BoNT's proposed mechanism of action is described as decreasing sensitized nociception in four ways by (1) inhibiting glutamate release in peripheral tissues, (2) decreasing calcitonin gene-related peptide release in peripheral tissue, (3) decreasing transient receptor potential cation channel subfamily V member 1 trafficking to peripheral neuron cell membrane, and (4) decreasing substance P release in peripheral tissue. This review discusses pertinent cellular/animal basic science research in conjunction with clinical research with regard to the role of BoNT in treating neuropathic pain.

Headache direction and aura predict migraine responsiveness to rimabotulinumtoxin B

OBJECTIVE

To report a retrospective analysis of patients with migraine headaches treated with rimabotulinumtoxin B as preventive treatment, investigating an association between clinical responsiveness with migraine directionality and migrainous aura.

BACKGROUND

The Phase III Research Evaluating Migraine Prophylaxis Therapy studies demonstrated onabotulinumtoxin A is effective in the preventive management of chronic migraine headaches. Jakubowski et al reported greater response to onabotulinumtoxin A in migraine patients reporting inward-directed head pain (imploding or ocular) compared with outward-directed head pain (exploding), suggesting subpopulations of patients may be better candidates for its use. No correlation was found between those reporting migrainous aura and onabotulinumtoxin A responsiveness.

METHODS

One hundred twenty-eight migraine patients were identified who had received rimabotulinumtoxin B injections over an average of 22 months, or 7 injection cycles. Migraine directionality was reported as inward directed (imploding, n = 72), eye centered (ocular, n = 28), outward directed (exploding, n = 16), and mixed (n = 12).

RESULTS

One hundred two out of one hundred twenty-eight patients (80%) improved; of these, 58 (57%) demonstrated a >75% reduction in monthly headache frequency (">75%-responders"), 76% of which noted sustained benefits >12 months with repeated injections every 10-12 weeks. Those reporting ocular- and imploding-directed headaches were significantly more likely to be >75%-responders, compared with exploding- and mixed-directed headaches (P < .0025). Patients with ocular-directed headaches were most likely to be sustained >75%-responders. Patients reporting migrainous aura were more likely to be >75%-responders (P = .0007). Those reporting exploding- and mixed-directed headaches were more likely to be nonresponders (P < .0001).

CONCLUSIONS

Reported migraine directionality and presence of migrainous aura predict migraine headache responsiveness to rimabotulinumtoxin B injections.

Critical analysis of the use of onabotulinumtoxinA (botulinum toxin type A) in migraine

OnabotulinumtoxinA, a neurotoxin, has been studied in numerous trials as a novel preventive therapy for migraine headache. The data would support that it may be effective at reducing headache days in patients suffering from chronic migraine (≥15 headache days/month, with eight or more of those migraine headache days). The mechanism by which onabotulinumtoxinA exerts its effects on migraine is not yet understood. It is known to inhibit acetylcholine release at the neuromuscular junction, but this probably does not explain the observed antinociceptive properties noted in preclinical and clinical trials. This review will discuss the known mechanisms of action of botulinum toxin type A, and will review the available randomized, placebo-controlled trials that have looked at its efficacy as a migraine preventative. We also describe the onabotulinumtoxinA injection sites used at our institution.

Treatment of refractory pain with botulinum toxins--an evidence-based review

OBJECTIVES

To provide updated information on the role of botulinum toxins in the treatment of refractory pain based on prospective, randomized, double-blind, placebo-controlled studies. DESIGN OF THE REVIEW: Class I and class II articles were searched online through PubMed (1966 to the end of January 2011) and OvidSP including ahead-of-print manuscripts.

RESULTS

Level A evidence (two or more class I studies-established efficacy): pain of cervical dystonia, chronic migraine, and chronic lateral epicondylitis. Level B evidence (one class I or two class II studies-probably effective and recommended): post-herpetic neuralgia, post-traumatic neuralgia, pain of plantar fasciitis, piriformis syndrome, and pain in total knee arthroplasty. Level C evidence (one class II study-possibly effective, may be used at discretion of clinician): allodynia of diabetic neuropathy, chronic low back pain, painful knee osteoarthritis, anterior knee pain with vastus lateralis imbalance, pelvic pain, post-operative pain in children with cerebral palsy after adductor hip release surgery, post-operative pain after mastectomy, and sphincter spasms and pain after hemorrhoidectomy. Level U evidence (efficacy not proven due to diverse class I and II results): myofascial pain syndrome and chronic daily headaches. Studies in episodic migraine and tension headaches have shown treatment failure (level A-negative).

CONCLUSION

Evidence-based data indicate that administration of botulinum toxin in several human conditions can alleviate refractory pain. The problems with some study designs and toxin dosage are critically reviewed.

Clinical profile of cluster headaches in Japan: low prevalence of chronic cluster headache, and uncoupling of sense and behaviour of restlessness

INTRODUCTION

This study examined the clinical profile of cluster headaches in Japan and the potential presence of features peculiar to Japan. Most previous studies of cluster headaches have focused on Caucasian populations.

METHODS

Subjects comprised 86 consecutive new cluster headache patients (68 males, 18 females; mean age, 38.4 ± 12.2 years; range, 17-73 years). Mean age at onset was 31.0 years and the ratio of males to females was 3.8:1.

RESULTS

Chronic cluster headache was observed in 3.5% of patients. More than half of patients (68.9%) reported feelings of restlessness during headache episodes and 42.9% reported restless behaviour. Patients with uncoupling of feelings of restlessness and restless behaviour forced themselves to keep still. Similar findings were reported in a Taiwanese study.

CONCLUSION

Japanese patients in this study showed a relatively low prevalence of chronic cluster headaches, and uncoupling of a sense of restlessness and restless behaviour. These features of cluster headache may be more common in Japanese and Taiwanese patients than in Caucasian patients.

Re-engineering clostridial neurotoxins for the treatment of chronic pain: current status and future prospects

Clostridial neurotoxins from the botulinum neurotoxin (BoNT) family are protein complexes, derived from the bacterium Clostridium botulinum, which potently inhibit acetylcholine release and result in a reversible blockade of the neuromuscular junction. This feature led to the clinical development of BoNT-A for a number of neuromuscular disorders. BoNT-A toxins are commercially available as three different preparations: Dysport/Azzalure, Botox/Vistabel, and Xeomin/Bocouture. Although BoNT-A preparations have not yet been approved for the treatment of pain, a substantial body of preclinical and clinical evidence shows that BoNT-A is effective in treating a number of different types of pain. It is thought to exert an analgesic effect both via muscle-relaxant properties and also directly, via inhibition of nociceptive neuropeptides. This review explores the mechanistic basis of this analgesic effect, summarizing current knowledge of the structure-function relationship of BoNT and discussing effects on both motor and pain neurons. For a complete picture of the analgesic properties of BoNT-A, clinical evidence of efficacy in myofascial pain and neuropathic pain is considered in tandem with a mechanistic rationale for activity. Patients experiencing chronic pain are clear candidates for treatment with a modified clostridial endopeptidase that would provide enduring inhibition of neurotransmitter release. A strong preclinical evidence base underpins the concept that re-engineering of BoNT could be used to enhance the analgesic potential of this neurotoxin, and it is hoped that the first clinical studies examining re-engineered BoNT-A will confirm this potential.

Botulinum neurotoxin in the treatment of headache disorders

Botulinum neurotoxin (BoNT) has been in clinical use for the treatment of headaches for over 15 years. Recent double-blind placebo-controlled trials have confirmed the efficacy of BoNT type A (onabtoulinumtoxinA, Botox) in the treatment of chronic migraine. The efficacy of BoNT in the treatment of episodic migraine headaches, cluster headaches, and chronic tension-type headache (TTH) has not been examined in large controlled trials. Presumed mechanisms of action of BoNT in headache disorders are the reduction of afferent input induced by muscle relaxation and inhibition of the release of neurotransmitters, such as glutamate and calcitonin gene-related peptide, from peripheral sensory nerve terminals. Over 20 years of extensive clinical experience has established a remarkable safety for BoNT, particularly type A and specifically Botox or onabotulinumtoxinA, which has been used much longer and more widely than any other form or serotype of BoNT. Because BoNT is a biological product, the safety and efficacy of one BoNT formulation cannot be extrapolated to a different one, even of the same serotype.

Is botulinum toxin useful in treating headache? No

The discrepancy between the widespread use of botulinum neurotoxin (BoNT) in managing headache and the supporting clinical evidence is unprecedented. No substance seems to have inspired more physicians and patients to undertake spirited treatment attempts. Tremendous treatment success in small, uncontrolled clinical trials has been repeatedly reported, but no substance that has been studied to an equal extent has so utterly failed to provide proof of effect in controlled clinical trials. Nevertheless, even though most randomized, controlled clinical trials have not met their defined primary outcome criterion, BoNT is still considered a promising treatment alternative for primary headache disorders. Experimental approaches to the pathophysiologic impact of BoNT on the perception of pain have been equally unsuccessful. Although most studies have been unable to find a direct antinociceptive effect in humans, some researchers continue to seek specific injection sites or injection techniques that may promise more successful results. Others look for a positive effect by narrowing the indications for BoNT to more homogenous symptoms or special patient subgroups. The results of randomized, controlled studies involving a total of 3552 patients indicate that BoNT injection is probably ineffective for patients with migraine and chronic tension-type headache regardless of injection site, dosage, or injection regimen, and there is insufficient evidence to draw a conclusion about its effectiveness for the treatment of chronic daily headache or subforms. The lack of direct experimental or clinical trial evidence that BoNT has a direct antinociceptive effect in humans must be addressed before more trials are conducted, involving even more patients. Additional pathophysiologically oriented research is also needed to unravel the mechanisms of action of BoNT in human pain perception or, alternatively, to bring it all down to the placebo effect.

Is botulinum toxin useful in treating headache? Yes

Recent scientific data support an effect of botulinum neurotoxin (BoNT) on pain and headache. BoNT was shown to affect the release of neurotransmitters that are important in pain transmission and in migraine pathogenesis. Data from both animal and clinical studies suggest that the toxin may have an analgesic effect that is independent from its effect on muscle tone. The high tolerability and long duration of action of the drug make it appealing as a potential prophylactic treatment for headache patients. Results of controlled trials on the efficacy of BoNT in the treatment of episodic migraine (EM) are mostly negative, although some subgroups of patients (eg, those with high attack frequency) may respond to the drug. Studies of patients with chronic daily headache have been inconclusive, although (as with the EM studies) specific subgroups of patients appear to benefit from the drug. BoNT is probably ineffective for the treatment of chronic tension-type headache. There are anecdotal reports on a positive effect of BoNT in patients with other types of headache (eg, nummular headache). Factors that may affect the response of patients to BoNT include headache characteristics, disease duration, the use of concurrent preventive medications, and the presence or absence of medication overuse. The authors' clinical experience shows that some headache patients benefit significantly from BoNT treatment. The challenge for future studies is to identify those patients who will best respond to the drug.

Botulinum neurotoxins in the treatment of refractory pain

The proper management of pain is a critical issue in the practice of medicine. Despite the availability of a large number of analgesic medications, management of pain that is refractory to conventional treatments remains a challenge for both clinicians and surgeons. Botulinum neurotoxin (BoNT) has recently emerged as a potential novel approach to control pain. Animal studies have revealed a number of mechanisms by which BoNTs can influence and alleviate chronic pain, including inhibition of pain peptide release from nerve terminals and sensory ganglia, anti-inflammatory and antiglutaminergic effects, reduction of sympathetic neural discharge, and inhibition of muscle spindle discharge. In humans, prospective, placebo-controlled, double-blind studies have also provided evidence for effectiveness of BoNT therapy in a number of painful disorders. These include cervical dystonia, pelvic pain, low back pain, plantar fasciitis, postsurgical painful spasms, myofascial pain syndromes, migraine, and chronic daily headaches. Long-term studies on cervical dystonia and low back pain have demonstrated safety and sustained efficacy after repeated injections. This Review focuses on the analgesic effects of BoNT and the mechanisms of its pain control as revealed by animal models, and provides evidence-based data on the efficacy of BoNT therapy in various pain syndromes in humans.

Botulinum toxin: could it be an effective treatment for chronic tension-type headache?

Several clinical trials suggest that botulinum toxin type-A (BTX-A) may be an effective treatment option for patients with chronic tension-type headache (CTTH); however, controversy remains as to how the botulinum toxin optimally should be used for treating headache and which patient's profile fits this treatment. The objective of this study was to evaluate the efficacy and tolerability of BTX-A for the prophylactic treatment of CCTH in Egyptian patients. This was a randomized, single-blind, placebo-controlled study of BTX-A for the treatment of patients aged 25-50 years old with CCTH. Following a 30-day screening, headache parameters and severity assessed by the standard visual analogue scale (VAS), and the 25-item Henry Ford Hospital Headache Disability Inventory (HDI) were recorded as a baseline. Then, injection was done with either BTX-A or with saline by a combination of two methods for detecting injection sites (the fixed-site approach and follow-the-pain approach). Our study showed significant improvement after 1 month of BTX-A injection regarding headache days/month, severity measured by VAS and HDI in headache severity. There was significant reduction of prophylactic medications, and there were minor complications, but these reversed spontaneously without further treatment. BTX-A was an effective and well-tolerated prophylactic treatment in Egyptian patients with CCTH.

Pericranial injection of botulinum toxin type A (Dysport) for tension-type headache - a multicentre, double-blind, randomized, placebo-controlled study

Increasingly, botulinum type A toxin is used to influence pathologically increased muscle activity in conditions such as dystonia and spasticity. Studies have also assessed its efficacy in tension-type headache, where muscle tenderness may be increased. We undertook a prospective, multicentre, randomized, double-blind, placebo-controlled trial. Patients received injections of Dysport (total dose of 420 or 210 units) or saline placebo in 18 sites on the head and neck. Of 125 patients treated, 118 were included in the intention-to-treat dataset. No significant differences between each verum group and placebo were seen for the primary efficacy parameter - change in the number of headache-free days at 4-8 weeks after injection compared with 4 weeks before injection. The groups receiving 420 or 210 units of Dysport experienced 2.60 and 2.87 more headache-free days respectively, compared with 1.93 more headache-free days for the placebo group (P = 0.66 versus 420 units; P = 0.52 versus 210 units). Treatment with 420 units of Dysport was associated with significant improvements compared with placebo for two secondary efficacy parameters: mean change in headache duration from baseline to weeks 8-12 (P < 0.05) and improved global physician and patient assessment scores (P < 0.05). Further studies should address the possible value of multiple injections with extended observation periods, dose optimization, and whether duration of headache history and number of previous treatments are predictors of patient response.

Botulinum toxin type a in the prophylactic treatment of transformed migraine in Taiwanese patients: a review of 30 consecutive cases

BACKGROUND

Botulinum toxin type A (BoNT-A) for the treatment of patients with various forms of migraine has been studied, but there is a paucity of data regarding the use of BoNT-A in Asian headache patients. Our study was designed to evaluate the efficacy of BoNT-A in the treatment of transformed migraine (TM) in a population of Taiwanese patients.

METHODS

We retrospectively analyzed 30 patients who underwent BoNT-A treatment for TM from July 2003 to May 2004. Of 30 patients, 14 had palpable muscle tenderness (or tender points) in the pericranial region and 16 did not. All patients received injections into the corrugator, procerus, frontalis, and temporalis muscles (a total of 30 U), while a subset of TM patients with tender points (6 of 14 patients) also received injections to additional muscles based on a follow-the-tenderness approach (mean dose, 45 U).

RESULTS

Twenty-seven of the 30 patients (90%) surveyed reported effective relief of their symptoms with BoNT-A treatment (at least a 50% reduction in the number of headache days or in headache intensity). The greatest reduction in headache days per month and headache intensity was found in TM patients with tender points who received a mean dose of 45 U compared to those who received fixed-site dosing of 30 U.

CONCLUSION

Our results suggest that BoNT-A may be an effective prophylactic treatment for TM in Taiwanese patients. Interestingly, similar efficacy was demonstrated in TM patients with tender points compared to those without tender points when an additional dose of BoNT-A was injected into the tender muscles in the former.