Evidence-based interventional pain medicine according to clinical diagnoses. 2. Cluster headache

An open-label observational study and meta-analysis of non-invasive vagus nerve stimulation in medically refractory chronic cluster headache

Background

Many patients with cluster headache (CH) are inadequately controlled by current treatment options. Non-invasive vagus nerve stimulation (nVNS) is reported to be effective in the management of CH though some studies suggest that it is ineffective.

Objective

To assess the safety and efficacy of nVNS in chronic cluster headache (CCH) patients.

Method

We prospectively analysed data from 40 patients with refractory CCH in this open-label, observational study. Patients were seen in tertiary headache clinics at the National Hospital for Neurology and Neurosurgery and trained to use nVNS as preventative therapy. Patients were reivewed at one month and then three-monthly from onset. The primary endpoint was number of patients achieving ≥50% reduction in attack frequency at 3  months. A meta-analysis of all published studies evaluating the efficacy of nVNS in CCH was also conducted. We searched MEDLINE and EMBASE for all studies investigating the use of nVNS as a preventive or adjunctive treatment for CCH with five or more participants. Combined mean difference and responder proportions with 95% confidence intervals (CI) were calculated from the included studies.

Results

17/40 patients (43%) achieved ≥50% reduction in attack frequency at 3  months. There was a significant reduction in monthly attack frequency from a baseline of 124 (±67) attacks to 79 (±63) attacks in month 3 (mean difference 44.7; 95% CI 25.1 to 64.3; p < 0.001). In month 3, there was also a 1.2-point reduction in average severity from a baseline Verbal Rating Scale of 8/10 (95% CI 0.5 to 1.9; p = 0.001). Four studies, along with the present study, were deemed eligible for meta-analysis, which showed a responder proportion of 0.35 (95% CI 0.07 to 0.69, n = 137) and a mean reduction in headache frequency of 35.3 attacks per month (95% CI 11.0 to 59.6, n = 108), from a baseline of 105 (±22.7) attacks per month.

Conclusion

This study highlights the potential benefit of nVNS in CCH, with significant reductions in headache frequency and severity. To better characterise the effect, randomised sham-controlled trials are needed to confirm the beneficial response of VNS reported in some, but not all, open-label studies.

Trigeminal neuralgia: An overview from pathophysiology to pharmacological treatments

The trigeminal nerve (V) is the fifth and largest of all cranial nerves, and it is responsible for detecting sensory stimuli that arise from the craniofacial area. The nerve is divided into three branches: ophthalmic (V1), maxillary (V2), and mandibular (V3); their cell bodies are located in the trigeminal ganglia and they make connections with second-order neurons in the trigeminal brainstem sensory nuclear complex. Ascending projections via the trigeminothalamic tract transmit information to the thalamus and other brain regions responsible for interpreting sensory information. One of the most common forms of craniofacial pain is trigeminal neuralgia. Trigeminal neuralgia is characterized by sudden, brief, and excruciating facial pain attacks in one or more of the V branches, leading to a severe reduction in the quality of life of affected patients. Trigeminal neuralgia etiology can be classified into idiopathic, classic, and secondary. Classic trigeminal neuralgia is associated with neurovascular compression in the trigeminal root entry zone, which can lead to demyelination and a dysregulation of voltage-gated sodium channel expression in the membrane. These alterations may be responsible for pain attacks in trigeminal neuralgia patients. The antiepileptic drugs carbamazepine and oxcarbazepine are the first-line pharmacological treatment for trigeminal neuralgia. Their mechanism of action is a modulation of voltage-gated sodium channels, leading to a decrease in neuronal activity. Although carbamazepine and oxcarbazepine are the first-line treatment, other drugs may be useful for pain control in trigeminal neuralgia. Among them, the anticonvulsants gabapentin, pregabalin, lamotrigine and phenytoin, baclofen, and botulinum toxin type A can be coadministered with carbamazepine or oxcarbazepine for a synergistic approach. New pharmacological alternatives are being explored such as the active metabolite of oxcarbazepine, eslicarbazepine, and the new Nav1.7 blocker vixotrigine. The pharmacological profiles of these drugs are addressed in this review.

Interventional Radiofrequency Treatment for the Sympathetic Nervous System: A Review Article

Introduction

Interventional techniques such as radiofrequency (RF) treatment can be used to interrupt pain signals transmitted through the sympathetic nervous system (SNS). RF treatments including the pulsed (PRF) and continuous (CRF) modalities show enhanced control over lesion size and enhanced ability to confirm accurate positioning compared to other interventional methods. PRF also acts to reduce the area of the lesion. In this article, we characterize the currently available evidence supporting the use and efficacy of RF treatments in sympathetically mediated pain (SMP) conditions.

Study Design

A comprehensive literature review.

Methods

A PubMed and Cochrane Library database search was performed for human studies applying RF treatment at sympathetic sites (sphenopalatine ganglion, stellate ganglion, cervical, thoracic, or lumbar sympathetic ganglia, celiac plexus, splanchnic nerves, superior hypogastric plexus, and ganglion impar) between January 1970 to May 2020. Data were extracted, summarized into tables, and qualitatively analyzed.

Results

PRF and CRF both show promise in relieving SMP conditions, such as complex regional pain syndrome (CRPS), pain in the perineal region, headache and facial pain, and oncologic and non-oncologic abdominal pain, in addition to other types of pain, with minimal complications. Furthermore, in most comparative studies, outcomes using RF treatments exceeded other interventional techniques, such as anesthetic block and chemical neurolysis.

Conclusions

RF treatments can be effective in carefully selected patients who are refractory to conservative management. However, further randomized controlled studies are needed prior to implementing it into common practice.

Public policies in headache disorders: needs and possibilities

Although headaches have recognized impact, there are no public policies in Brazil addressing this problem. The Brazilian Headache Society and the Brazilian Association of Cluster Headache and Migraine promoted a summit to discuss Public Policy and Advocacy for headache disorders. Professionals from various segments, representing various sectors of society, gathered in April 2019 in Brasília, defining the most important points for achieving advances in public policies in headache in Brazil, such as: inclusion in the chronic diseases surveillance agenda; improving public understanding and access to diagnosis and treatment; teaching in colleges and medical residences, structuring care networks, intervention models, clinical protocols and legislation supporting public policies in headache.

"Evidence-Based Interventional Pain Medicine According to Clinical Diagnoses": Update 2018

Introduction

Between 2009 and 2011 a series of 26 articles on evidence‐based medicine for interventional pain medicine according to clinical diagnoses were published. The high number of publications since the last literature search justified an update.

Methods

For the update an independent 3rd party, specialized in systematic reviews was asked in 2015 to perform the literature search and summarize relevant evidence using Cochrane and GRADE methodology to compile guidelines on interventional pain management. The guideline committee reviewed the information and made a last update on March 1st 2018. The information from new studies published after the research performed by the 3th party and additional observational studies was used to incorporate other factors such as side effects and complications, invasiveness, costs and ethical factors, which influence the ultimate recommendations.

Results

For the different indications a total of 113 interventions were evaluated. Twenty‐seven (24%) interventions were new compared to the previous guidelines and the recommendation changed for only 3 (2.6%) of the interventions.

Discussion

This article summarizes the evolution of the quality of evidence and the strength of recommendations for the interventional pain treatment options for 28 clinical pain diagnoses.

Efficacy of Sphenopalatine Ganglion Radiofrequency in Refractory Chronic Cluster Headache

BACKGROUND

In the literature, there are only short series of radiofrequency of the sphenopalatine ganglion (SPG) to treat chronic refractory cluster headache (CCHr) with variable results. Furthermore, there is no consensus on which methodology to use: radiofrequency ablation (RFA) or pulsed radiofrequency (PRF).

METHODS

We conducted a prospective analysis of 37 patients with CCHr who underwent RFA or PRF of the SPG in our center between 2004 and 2015.

RESULTS

The mean age of the patients was 40 years (range, 26-59 years). PRF was performed in 24 patients, and RFA was performed in 13 patients. A total of 5 patients (13.5%) experienced complete clinical relief of both pain and parasympathetic symptoms, 21 patients (56.8%) had partial and transient relief, and 11 patients (29.7%) did not improve. There was no evidence of significant superiority of one radiofrequency modality over the other (P = 0.48). There were no complications associated with the technique. The passage of time tended to decrease the efficacy of both techniques (P < 0.001). The mean follow-up was 68.1 months (range, 15-148 months). To our knowledge, this is the series with the largest number of patients and the longest follow-up period published in the literature.

CONCLUSIONS

Radiofrequency of the SPG is a safe, fast, and partially effective method for the treatment of CCHr. Given its low rate of complications and its low economic cost, we think it should be one of the first invasive treatment options, prior to techniques with greater morbidity and mortality, such as neuromodulation.

Refractory chronic cluster headache: a consensus statement on clinical definition from the European Headache Federation

Chronic cluster headache (CCH) often resists to prophylactic pharmaceutical treatments resulting in patients’ life damage. In this rare but pragmatic situation escalation to invasive management is needed but framing criteria are lacking. We aimed to reach a consensus for refractory CCH definition for clinical and research use. The preparation of the final consensus followed three stages. Internal between authors, a larger between all European Headache Federation members and finally an international one among all investigators that have published clinical studies on cluster headache the last five years. Eighty-five investigators reached by email. Proposed criteria were in the format of the International Classification of Headache Disorders III-beta (description, criteria, notes, comments and references). Following this evaluation eight drafts were prepared before the final. Twenty-four (28.2%) international investigators commented during two rounds. Refractory CCH is described in the present consensus as a situation that fulfills the criteria of ICHD-3 beta for CCH with at least three severe attacks per week despite at least three consecutive trials of adequate preventive treatments. The condition is rare, but difficult to manage and invasive treatments may be needed. The consensus addresses five specific clinical and paraclinical diagnostic criteria followed by three notes and specific comments. Although refractory CCH may be not a separate identity these specific diagnostic criteria should help clinicians and investigators to improve patient’s quality of life.

Sphenopalatine endoscopic ganglion block in cluster headache: a reevaluation of the procedure after 5 years

Cluster headache (CH) is considered the most painful form of primary headaches. It is characterized by severe unilateral pain, typically associated with autonomic manifestations and may be divided into an episodic and a chronic form. The latter is often resistant to a multitude of medication and is, therefore, very hard to treat. In 2002, our group developed a technique for the endoscopic sphenopalatine ganglion block that was able to ameliorate the symptoms in 55% of drug-resistant chronic CH patients. This paper is intended as an update on the technique as well as a comparison in effectiveness to our prior approach.

Occipital nerve stimulation for headache disorders

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

Evidence-based interventional pain medicine according to clinical diagnoses. 3. Persistent idiopathic facial pain

Persistent idiopathic facial pain, previously known as atypical facial pain, is described as a persistent facial pain that does not have the classical characteristics of cranial neuralgias and for which there is no obvious cause (International Classification of Headache Disorders in 2004). According to these criteria, the diagnosis is possible if the facial pain is localized, present daily, and throughout all or most of the day. By definition, neurological and physical examination findings in persistent idiopathic facial pain should be normal. Forming a diagnosis is not simple and follows a process of elimination of other causes of facial pain. The precise incidence is unknown. The affliction is seen primarily in older adults and rarely in children. The pathophysiology is unknown. In persistent idiopathic facial pain, there is no abnormal processing of somatosensory stimuli in the pain area or facial area of the primary somatosensory cortex of the brain. The treatment is difficult and often requires a multidisciplinary approach. The most important part of the treatment is psychological counseling and pharmacological therapy. Pharmacological treatment with tricyclic antidepressants and anti-epileptic drugs can be tried. The conservative, pharmacological treatment with amitryptiline is the primary choice. Venlafaxine and fluoxetine treatment can also be considered. When the pharmacological treatment fails, pulsed radiofrequency treatment of the ganglion pterygopalatinum (sphenopalatinum) can be considered (2 C+).