A systematic review of rescue analgesic strategies in acute exacerbations of primary trigeminal neuralgia

An update on pharmacotherapy for trigeminal neuralgia

INTRODUCTION

Trigeminal neuralgia is a rare condition that can be effectively treated by carbamazepine or oxcarbazepine but these older drugs are associated with dose-dependent and potentially treatment-limiting adverse effects. Third-generation anticonvulsants, new calcitonin gene-related peptide blockers for migraine, and older drugs such as ketamine and cannabinoids may be promising adjuvants or monotherapeutic options.

AREAS COVERED

The new drugs, their presumed mechanisms of action, safety and efficacy are discussed herein. There is a paucity of robust clinical evidence in support of these drugs for trigeminal neuralgia. New migraine agents are considered as well although migraines and trigeminal neuralgia are distinct, albeit similar, conditions. No new drugs have been released to market in recent years with the specific indication of trigeminal neuralgia.

EXPERT OPINION

In real-world clinical practice, about half of trigeminal neuralgia patients take more than one agent for prevention and combination therapy may be the optimal approach. Combination therapy might allow for lower doses of carbamazepine or oxcarbazepine, thus reducing the number and severity of potential adverse events but the potential for pharmacokinetic drug-drug interactions must be considered. Drug therapy for trigeminal neuralgia involves acute or abortive treatments, often administered in hospital versus long-term preventive therapy, usually involving oral agents.

Trigeminal neuralgia

Trigeminal neuralgia (TN) is a facial pain disorder characterized by intense and paroxysmal pain that profoundly affects quality of life and presents complex challenges in diagnosis and treatment. TN can be categorized as classical, secondary and idiopathic. Epidemiological studies show variable incidence rates and an increased prevalence in women and in the elderly, with familial cases suggesting genetic factors. The pathophysiology of TN is multifactorial and involves genetic predisposition, anatomical changes, and neurophysiological factors, leading to hyperexcitable neuronal states, central sensitization and widespread neural plasticity changes. Neurovascular compression of the trigeminal root, which undergoes major morphological changes, and focal demyelination of primary trigeminal afferents are key aetiological factors in TN. Structural and functional brain imaging studies in patients with TN demonstrated abnormalities in brain regions responsible for pain modulation and emotional processing of pain. Treatment of TN involves a multifaceted approach that considers patient-specific factors, including the type of TN, with initial pharmacotherapy followed by surgical options if necessary. First-line pharmacological treatments include carbamazepine and oxcarbazepine. Surgical interventions, including microvascular decompression and percutaneous neuroablative procedures, can be considered at an early stage if pharmacotherapy is not sufficient for pain control or has intolerable adverse effects or contraindications.

"Status trigeminal neuralgia": Analysis of 39 cases and proposal for diagnostic criteria

OBJECTIVE

The aim of this descriptive study was to propose diagnostic criteria for acute exacerbation of trigeminal neuralgia (TN) based on the analysis of retrospective cases.

BACKGROUND

TN is a rare and extremely painful condition whose evolution can be punctuated by major exacerbations, leading to significant functional impairment. Several denominations are used for these exacerbations: "acute exacerbation", "status of trigeminal neuralgia", and "status trigeminus". There is currently no clinical definition of this state. In this manuscript, we used the term "status trigeminal neuralgia" (STN).

METHODS

We conducted a retrospective study, in a tertiary care specialist headache center, in France. Patients were selected from January 2015 to October 2022, with the French translation of the keyword "STN", in the medical records (outpatients) or the codage for trigeminal neuralgia (inpatients). Additional cases of STN were prospectively recruited from October 2022 to February 2023. We analyzed the clinical and paraclinical data of these patients.

RESULTS

Thirty-nine patients presenting with STN were included. There was a preponderance of women (64%) with 24 cases of classic TN (62%) and 15 cases of secondary TN (38%). Concerning STN, 39 episodes were described. Pain was very severe in all patients. Cranial autonomic signs were present in 23% of cases. Pain extended beyond the usual territory in 44% of cases. A continuous pain background was present in 35% of cases. With regard to triggering factors, paroxysms of facial pain were triggered by eating (97% of patients), speaking (90%) or drinking (62% of patients). Repercussions on weight, hydration, or mood disorders were observed in 67%, 56% and 59% of the cases, respectively.

CONCLUSION

STN is a rare clinical presentation of TN. We proposed criteria and a new denomination for this condition.

Modern Approaches to the Treatment of Acute Facial Pain

PURPOSE OF REVIEW

Acute facial pain presents a complex challenge in medical practice, requiring a comprehensive and interdisciplinary approach to its management. This narrative review explores the contemporary landscape of treating acute facial pain, delving into pharmacological, non-pharmacological, and advanced interventions. The significance of tailored treatment strategies, rooted in the diverse etiologies of facial pain, such as dental infections, trigeminal neuralgia, temporomandibular joint disorders, sinusitis, or neurological conditions like migraines or cluster headaches, is underscored. We particularly emphasize recent advances in treating trigeminal neuralgia, elucidating current treatment concepts in managing this particular acute facial pain.

RECENT FINDINGS

Recent research sheds light on various treatment modalities for acute facial pain. Pharmacotherapy ranges from traditional NSAIDs and analgesics to anticonvulsants and antidepressants. Non-pharmacological interventions, including physical therapy and psychological approaches, play pivotal roles. Advanced interventions, such as nerve blocks and surgical procedures, are considered in cases of treatment resistance. Moreover, we explore innovative technologies like neuromodulation techniques and personalized medicine, offering promising avenues for optimizing treatment outcomes in acute facial pain management. Modern management of acute facial pain requires a nuanced and patient-centric approach. Tailoring treatment strategies to the individual's underlying condition is paramount. While pharmacotherapy remains a cornerstone, the integration of non-pharmacological interventions is essential for comprehensive care. Advanced interventions should be reserved for cases where conservative measures prove inadequate. Furthermore, leveraging innovative technologies and personalized medicine holds promise for enhancing treatment efficacy. Ultimately, a holistic approach that considers the diverse needs of patients is crucial for effectively addressing acute facial pain.

Cranial Neuralgias

OBJECTIVE

The cranial neuralgias are relatively rare, but recognizing these syndromes and distinguishing among them is critical to reducing unnecessary pain and disability for affected patients. Despite their distinctive features, cranial neuralgias may go undiagnosed or misdiagnosed for several years. A notable proportion of cranial neuralgia presentations are due to secondary causes and require targeted treatment. The purpose of this article is to review the diagnosis and management of cranial neuralgias encountered in clinical practice.

LATEST DEVELOPMENTS

In 2020, the International Classification of Orofacial Pain was released for the first time. Modeled after the International Classification of Headache Disorders, it includes updated terminology for cranial neuralgias. The underlying pathophysiology of the cranial neuralgias is currently believed to be rooted in both peripheral and central nociceptive systems. In addition, a growing number of familial cases are being identified. Recent therapeutic advancements include a better understanding of how to utilize older therapies and procedures more effectively as well as the development of newer approaches.

ESSENTIAL POINTS

Cranial neuralgia syndromes are rare but important to recognize due to their debilitating nature and greater likelihood of having potentially treatable underlying causes. While management options have remained somewhat limited, scientific inquiry is continually advancing the understanding of these syndromes and how best to address them.

Intranasal Lidocaine Administration via Mucosal Atomization Device: A Simple and Successful Treatment for Postdural Puncture Headache in Obstetric Patients

(1) Background: Postdural puncture headache (PDPH) remains a serious complication in obstetric patients. While the epidural blood patch represents the current gold standard in therapy, a growing number of alternative measures are thought to be beneficial for clinical management. The purpose of this study was to retrospectively analyze the efficacy of intranasal lidocaine administration to treat PDPH in obstetrics at our university hospital; (2) Methods: A retrospective analysis of the medical records of patients with PDPH has been performed focusing on the techniques of administration, dosing, treatment duration, impact on pain intensity as well as side effects of intranasal lidocaine; (3) Results: During the study period, 5610 obstetric patients received neuraxial anesthesia, of whom 43 (0.77%) developed PDPH. About one third of the patients with PDPH after spinal anesthesia (n = 8), epidural anesthesia (n = 5) or both (n = 2) were treated with intranasal lidocaine. Lidocaine was administered either via gauze compresses (GC, n = 4), a mucosal atomization device (MAD, n = 8) or with a second-line mucosal atomization device due to low gauze compress efficacy (n = 3). All patients treated with lidocaine refused the epidural blood patch. Nebulization of lidocaine resulted in a significant reduction in pain intensity after the first dose (p = 0.008). No relevant side effects developed except sporadic temporal pharyngeal numbness. The utilization of the mucosal atomization device averted the necessity for an epidural blood patch, whether employed as the primary or secondary approach; (4) Conclusions: Our data imply that the mucosal atomization device enhances the efficacy of intranasal lidocaine administration in obstetric patients suffering from PDPH.

Therapeutic Approach for Trigeminal Neuralgia: A Systematic Review

This umbrella review aimed to determine the various drugs used to treat trigeminal neuralgia (TN) and to evaluate their efficacies as well as side effects by surveying previously published reviews. An online search was conducted using PubMed, CRD, EBSCO, Web of Science, Scopus, and the Cochrane Library with no limits on publication date or patients' gender, age, and ethnicity. Reviews and meta-analyses of randomized controlled trials pertaining to drug therapy for TN, and other relevant review articles added from their reference lists, were evaluated. Rapid reviews, reviews published in languages other than English, and reviews of laboratory studies, case reports, and series were excluded. A total of 588 articles were initially collected; 127 full-text articles were evaluated after removing the duplicates and screening the titles and abstracts, and 11 articles were finally included in this study. Except for carbamazepine, most of the drugs had been inadequately studied. Carbamazepine and oxcarbazepine continue to be the first choice for medication for classical TN. Lamotrigine and baclofen can be regarded as second-line drugs to treat patients not responding to first-line medication or for patients having intolerable side effects from carbamazepine. Drug combinations using carbamazepine, baclofen, gabapentin, ropivacaine, tizanidine, and pimozide can yield satisfactory results and improve the tolerance to the treatment. Intravenous lidocaine can be used to treat acute exaggerations and botulinum toxin-A can be used in refractory cases. Proparacaine, dextromethorphan, and tocainide were reported to be inappropriate for treating TN. Anticonvulsants are successful in managing trigeminal neuralgia; nevertheless, there have been few studies with high levels of proof, making it challenging to compare or even combine their results in a statistically useful way. New research on other drugs, combination therapies, and newer formulations, such as vixotrigine, is awaited. There is conclusive evidence for the efficacy of pharmacological drugs in the treatment of TN.

Is Botulinum Toxin Effective in Treating Orofacial Neuropathic Pain Disorders? A Systematic Review

BACKGROUND

The aim of this paper is to provide a systematic review of the literature regarding the clinical use of botulinum toxin (BTX) to treat various orofacial neuropathic pain disorders (NP).

METHODS

A comprehensive literature search was conducted using Medline, Web of Science, and the Cochrane Library databases. Only randomized clinical trials (RCT) published between 2003 and the end of June 2023, investigating the use of BTX to treat NP, were selected. PICO guidelines were used to select and tabulate the articles.

RESULTS

A total of 6 RCTs were selected. Five articles used BTX injections to treat classical trigeminal neuralgia, and one to treat post-herpetic neuralgia. A total of 795 patients received BTX injections. The selected studies utilised different doses and methods of injections and doses. All the selected studies concluded superiority of BTX injections over placebo for reducing pain levels, and 5 out 6 of them highlighted an improvement in the patient's quality of life. Most of the studies reported transient and mild side effects.

CONCLUSION

There is evidence of the efficacy of BTX injections in orofacial pain management. However, improved study protocols are required to provide direction for the clinical use of BTX to treat various orofacial neuropathic pain disorders.

Pharmacological Management of Orofacial Pain

Orofacial pain is a category of complex disorders, including musculoskeletal, neuropathic and neurovascular disorders, that greatly affect the quality of life of the patient. These disorders are within the fields of dentistry and medicine and management can be challenging, requiring a referral to an orofacial pain specialist, essential for adequate evaluation, diagnosis, and care. Management is specific to the diagnosis and a treatment plan is developed with diverse pharmacological and non-pharmacological modalities. The pharmacological management of orofacial pain encompasses a vast array of medication classes and approaches. This includes anti-inflammatory drugs, muscle relaxants, anticonvulsants, antidepressants, and anesthetics. In addition, as adjunct therapy, different injections can be integrated into the management plan depending on the diagnosis and needs. These include trigger point injections, temporomandibular joint (TMJ) injections, and neurotoxin injections with botulinum toxin and nerve blocks. Multidisciplinary management is key for optimal care. New and safer therapeutic targets exclusively for the management of orofacial pain disorders are needed to offer better care for this patient population.

Non-Surgical Treatments of Trigeminal Neuralgia from the Perspective of a Pain Physician: A Narrative Review

Trigeminal neuralgia (TN) is a unilateral disorder characterized by electric shock-like pain, abrupt onset and termination, and limited to one or more branches of the trigeminal nerve. Various therapeutic modalities for TN have been introduced. We searched for literature indexed in PubMed, Medline, and the National Library of Medicine and reviewed all relevant articles on non-surgical treatments for TN. Published studies were reviewed with no restrictions on date; reviews, clinical trials, animal studies, retrospective studies, and cases were included. Carbamazepine and oxcarbazepine are the recommended first-line pharmacotherapies. Interventional treatments should be considered when pharmacotherapy is insufficient or withdrawn because of adverse effects.

Low-dose Fosphenytoin for Aborting Acute Trigeminal Neuralgia Pain: A Case Report

INTRODUCTION

While the typical treatment for trigeminal neuralgia is carbamazepine, the dose must be gradually titrated over time to achieve pain control, which makes the drug a less than ideal candidate for treatment for acute exacerbation of pain due to trigeminal neuralgia in the emergency department (ED) setting. The literature for other effective treatments for acute exacerbations of trigeminal neuralgia is currently lacking. We discuss a case where intravenous (IV) fosphenytoin was used for treatment of acute pain due to trigeminal neuralgia in the ED.

CASE REPORT

This is a case of a 35-year-old male diagnosed with trigeminal neuralgia who presented with acute facial pain. His history and physical exam were consistent with an acute exacerbation of his trigeminal neuralgia. The patient was refractory to multiple doses of standard pain medication in the ED, and the decision was made to attempt IV fosphenytoin to relieve his pain. He was given 250 milligrams of fosphenytoin that was infused via IV over 10 minutes. By the end of the infusion, the patient had reported complete resolution of his pain.

CONCLUSION

Fosphenytoin is a viable treatment option for pain relief in patients with acute exacerbation of trigeminal neuralgia. It may be a more favorable drug to use in the ED for acute pain given that carbamazepine must be titrated to effect. It is also possible that lower doses of fosphenytoin may provide equally beneficial analgesic effect than what is described in the literature, as pain relief was achieved in our case with approximately 3 milligrams/kilogram of fosphenytoin.

Phenytoin Decreases Pain-like Behaviors and Improves Opioid Analgesia in a Rat Model of Neuropathic Pain

Neuropathic pain remains a clinical challenge due to its complex and not yet fully understood pathomechanism, which result in limited analgesic effectiveness of the management offered, particularly for patients with acute, refractory neuropathic pain states. In addition to the introduction of several modern therapeutic approaches, such as neuromodulation or novel anti-neuropathic drugs, significant efforts have been made in the repurposing of well-known substances such as phenytoin. Although its main mechanism of action occurs at sodium channels in excitable and non-excitable cells and is well documented, how the drug affects the disturbed neuropathic interactions at the spinal cord level and how it influences morphine-induced analgesia have not been clarified, both being crucial from a clinical perspective. We demonstrated that single and repeated systemic administrations of phenytoin decreased tactile and thermal hypersensitivity in an animal model of neuropathic pain. Importantly, we observed an increase in the antinociceptive effect on thermal stimuli with repeated administrations of phenytoin. This is the first study to report that phenytoin improves morphine-induced antinociceptive effects and influences microglia/macrophage activity at the spinal cord and dorsal root ganglion levels in a neuropathic pain model. Our findings support the hypothesis that phenytoin may represent an effective strategy for neuropathic pain management in clinical practice, particularly when combination with opioids is needed.

Microvascular Decompression for Concurrent Trigeminal Neuralgia and Hemi-Laryngopharyngeal Spasm: A Case Report

BACKGROUND AND IMPORTANCE

Hemi-laryngopharyngeal spasm (HeLPS) may result from vascular compression of the vagus nerve and can be treated using microvascular decompression. We describe the clinical characteristics and surgical treatment in a case of concurrent trigeminal neuralgia (TN) and HeLPS.

CLINICAL PRESENTATION

A 44-year-old man presented with a 12-month history of right TN and 8-month history of intermittent episodes of repeated throat contractions associated with a very distressing choking sensation. Preoperative 3-dimensional fusion imaging demonstrated compression of the trigeminal nerve by the superior cerebellar artery and petrosal vein and compression of the vagus nerve by the posterior inferior cerebellar artery and one of its branches. Microvascular decompression was performed by a right standard retrosigmoid approach with enlarged craniotomy. Initially, the compression of the trigeminal nerve was identified by visual inspection. All the offending vessels were wrapped in Teflon felt, transposed away from the trigeminal nerve, and adhered to the tentorial membrane and petrous bone using fibrin glue. Furthermore, observation of the caudal rootlets of the vagus nerve revealed that the posterior inferior cerebellar artery and its branch compressed the ventral side of the nerve. These vessels were displaced antero-caudally with Teflon felt and fibrin glue; no other vessels were found around the trigeminal and vagus nerves. Postoperatively, the patient had immediate and complete resolution of symptoms of TN and HeLPS without recurrence at the 18-month follow-up.

CONCLUSION

HeLPS may occur with TN, and neurosurgeons should identify the symptoms suspicious of this disease preoperatively.

A Potential Role for Steroids in Acute Pain Management in Patients with Trigeminal Neuralgia

OBJECTIVE

Effective therapies for acute pain management in trigeminal neuralgia (TN) are limited. We aimed to investigate the role of steroids in TN patients experiencing acute pain flares.

METHODS

We retrospectively reviewed patients presenting to the emergency department of a tertiary care institution between 2014 and 2020 for acute TN pain flares. Patients were divided into those who received steroids versus those who did not. Presenting characteristics, admission and surgical intervention rates, Barrow Neurological Institute pain scores, pain recurrence rates, and surgical intervention within 6 months of discharge were obtained for each patient.

RESULTS

Our cohort comprised 151 patients, of whom 40 (26.5%) received steroids before admission and/or discharge. These patients were less likely to undergo surgical intervention to treat acute pain (P = 0.023). Specifically, patients receiving steroids were less likely to undergo combined glycerin and radiofrequency rhizotomy compared with patients not receiving steroids (P = 0.012). Frequency and dosage of opioid administration did not differ between groups. The steroids group demonstrated a lower average Barrow Neurological Institute pain score on discharge compared with the no steroids group (P = 0.013). Patients receiving steroids for acute pain management were less likely to undergo surgical intervention within 6 months of discharge than patients who did not receive steroids (P = 0.033).

CONCLUSIONS

Steroid administration in patients with acute TN pain flares may reduce the likelihood of surgical intervention both during admission and within 6 months of discharge. Future prospective studies should examine the efficacy of steroids as an adjunctive medication in acute TN pain management.

Quality of life after trigeminal nerve block in refractory trigeminal neuralgia: A retrospective cohort study and literature review

OBJECTIVE

To evaluate the effect of trigeminal nerve block (TNB) on patients' quality of life (QOL) 15 days after the procedure in patients with refractory TN.

METHODS

This retrospective observational cohort study involved patients receiving TNB (levobupivacaine, clonidine, corticosteroid) between 2014 and 2018 at a postoperative pain clinic in France. Change in QOL from Day 0 (before block) to Day 15 was assessed according to SF-12.

RESULTS

21 patients (62 ± 14 y) were included in the study. Most patients (71%) were referred following surgery or dentistry. Of the 9 patients (43%) who exhibited >10% increase in SF-12 scores and so were deemed responders, SF12-physical and SF12-mental were increased by mean differences of 17 and 9 points, respectively. The mean duration of block lasted 15 ± 59 days (range 1 to 90 days) and no severe adverse effects were observed.

CONCLUSION

Improved QOL was observed in approximately 50% of patients with trigeminal neuralgia (TN) two weeks after specific nerve block. The technique was easy to administer and well accepted by the patients.

Effectiveness, Safety, and Predictors of Response to 5% Lidocaine-Medicated Plaster for the Treatment of Patients With Trigeminal Neuralgia: A Retrospective Study

BACKGROUND

Whether 5% lidocaine-medicated plaster (LMP) is a valuable therapeutic option for the treatment of trigeminal neuralgia (TN) is worth exploring. If LMP is proven effective for TN, positive predictors of the analgesic effects of LMP warrant further investigation.

OBJECTIVE

To evaluate the efficacy and safety of LMP for the treatment of TN, and to explore the predictive factors for the treatment efficacy of LMP.

METHODS

This is a retrospective and observational study. We analyzed the efficacy of LMP for the treatment of TN between March 2019 and January 2022. The follow-up time was approximately 2 weeks, 1 month, 2 months, and 3 months after LMP treatment. The LMP response was considered the Barrow Neurological Institute (BNI) score of I to III and an improvement in BNI of at least I grade from pretreatment baseline. Univariable and multivariable logistic analyses were performed to identify the predictive factors for LMP response.

RESULTS

A total of 103 patients were included and analyzed in this study. LMP was effective in some TN patients, with an efficacy rate of 21.4%, 21.4%, 18.4%, and 16.5% after 2 weeks, 1 month, 2 months, and 3 months of LMP treatment, respectively. The overall adverse event rate associated with LMP was 5.8%, and the reported adverse events were all skin reactions. Facial trigger points (odds ratio [OR] = 0.25, 95% confidence interval [CI] = 0.07-0.86, P = 0.03) and a lower BNI score (OR = 0.37, 95% CI = 0.07-0.87, P = 0.01) were identified as potential predictors for initial efficacy (2-week follow-up) of LMP treatment.

CONCLUSIONS AND RELEVANCE

LMP has been shown to provide effective and sustained analgesia in some TN patients with minimal risk of systemic adverse reactions. Patients with facial trigger points and mild to moderate pain are more likely to benefit from LMP treatment. Our data suggest that LMP may be an effective treatment option for patients with the aforementioned characteristics of TN.

Therapeutic Efficacy of Botulinum Toxin in Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a unilateral, paroxysmal, sharp, shooting, or jabbing pain that occurs in the trigeminal nerve divisions, including the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves. Typically, an episode is triggered by anything touching the face or teeth. TN is a clinical diagnosis with no specific diagnostic test; it is determined by the patient's medical history and pain description. Imaging is necessary to exclude secondary causes. The precise reason for TN is uncertain, but it is commonly believed to result from vascular compression of the trigeminal nerve root, typically near its origin in the pons. There are numerous surgical and medical treatment options available. The most frequently applied medical treatment therapies are carbamazepine and oxcarbazepine. Surgical alternatives are reserved for patients who do not respond to medical treatment. Botulinum toxin A (BTX-A) has emerged as a novel and promising alternative to surgery for individuals whose pain is unresponsive to medication. Multiple studies have established the safety and usefulness of BTX-A in treating TN, with the most significant benefits occurring between six weeks and three months after the surgery. This article reviews various studies published in the last 10 years regarding the therapeutic use of BTX-A in TN. These studies include various observational, clinical, pilot, and animal studies.

Intravenous lacosamide and phenytoin for the treatment of acute exacerbations of trigeminal neuralgia: A retrospective analysis of 144 cases

Background

Scant evidence is available on the use of intravenous pain treatment in acute exacerbations of trigeminal neuralgia. The aim of this descriptive study was to evaluate the effectiveness and security of intravenous lacosamide and phenytoin in the treatment of acute trigeminal neuralgia pain.

Methods

We reviewed patients who attended the emergency department of a tertiary hospital between 2012 and 2020 for exacerbations of trigeminal neuralgia pain and were treated with either intravenous phenytoin or lacosamide for the first time. Primary endpoints were pain relief and adverse effects during the hospital stay. A comparative analysis between both treatment groups was performed.

Results

We studied 144 episodes in 121 patients (median age 61 years, 66.1% women). Trigeminal neuralgia etiology was secondary in 9.9%. Pain relief was observed in 77.8% of 63 patients receiving lacosamide infusions, and adverse effects in 1.6%. Pain relief was observed in 72.8% of 81 phenytoin infusions and adverse effects in 12.3%, all mild. No difference was observed in pain relief between groups, but the proportion of adverse effects was significantly different (p = 0.023). Statistically significant differences were also detected in readmissions within six months, time to readmission, and pain relief status at first follow-up visit.

Conclusion

Intravenous lacosamide and phenytoin can be effective and safe treatments for acute pain in trigeminal neuralgia. According to our series, lacosamide might be better tolerated than phenytoin and lead to lower readmissions and sustained pain relief.

Intravenous fosphenytoin as treatment for acute exacerbation of trigeminal neuralgia: A prospective systematic study of 15 patients

INTRODUCTION

Intravenous fosphenytoin is widely used for acute exacerbation of trigeminal neuralgia, however, few studies have investigated this treatment. We aimed to examine the efficacy and side effects of initial intravenous fosphenytoin plus oral tapering of phenytoin for exacerbation of trigeminal neuralgia.

METHODS

Consecutive patients with primary trigeminal neuralgia were included in this prospective observational 90-days follow-up study. Data were collected using standardized interviews before, at 24 hours, day 7, 30 and 90 post loading dose. The primary outcome was the proportion of responders defined as a 50% reduction in pain intensity 24 hours post loading dose.

RESULTS

We included 15 patients. Nine patients (60%) were responders. Pain intensity 24 hours post loading dose was reduced by 5.00 points on the numerical rating scale (p < 0.001), and at day 7 by 5.5 points (p < 0.001). The most common side effects were hypotension and dizziness.

CONCLUSION

Intravenous fosphenytoin relieves trigeminal neuralgia pain in most patients and provides a window for titrating prophylactic trigeminal neuralgia medications or planning neurosurgery. The decision to administer intravenous fosphenytoin should be taken with support from trigeminal neuralgia experts and involves considerations of co-morbidities and other treatment options for acute exacerbation of trigeminal neuralgia.Clinical Trial: Preregistered (ClinicalTrials.gov Identifier: NCT03712254.

Recurrent Trigeminal Neuralgia: A Case Series and a Review of the Literature

Trigeminal neuralgia is a peripheral neuropathy characterized by intermittent episodes of severe facial pain originating in the sensory nucleus of the trigeminal nerve. The most commonly involved area is the mandibular division with a higher prevalence on the right side. Advances in the field of MRI have played an important role in its diagnosis, especially in presurgical assessment, to probe into any secondary causes of nerve compression and/or neurovascular conflict. The condition is primarily managed medically, although many patients may require surgical or radiotherapeutic intervention. A recurrence rate ranging from 6 to 41% has been postulated. Reasons for recurrence are mainly attributed to improper operative techniques, dislocation of the Teflon implant, or granuloma formation. MRI serves as a powerful tool in the segmental evaluation of the trigeminal nerve. A proper diagnosis with a structured treatment protocol is critical for managing such cases of trigeminal neuralgia. In this report, we present a series of two cases of recurrent trigeminal neuralgia.

A Narrative Review of Therapeutic Peripheral Nerve Blocks for Chronic Orofacial Pain Conditions

AIMS

To provide an analysis of the different therapeutic peripheral nerve blocks (PNBs), as well as their limitations and the related evidence base for their use in chronic orofacial pain (OFP) conditions, excluding migraine and other headache conditions.

METHODS/RESULTS

The evidence base for therapeutic PNBs for chronic OFP is poor and highlights the need for improved research in this area. The diagnostic criteria and interventional PNB definitions and techniques varied between studies. In addition, the placebo effect of a peripheral injection and its resultant bias was rarely considered. Most of the PNB interventions for temporomandibular disorders were for arthrogenous disorders (arthritis and disc entrapment with pain). However, there is emerging evidence for the use of onabotulinum toxin (BTX-A) in trigeminal neuralgia, with four prospective randomized controlled trials (pRCTs), and for postherpetic neuralgia. However, despite high-level evidence for BTX-A in posttraumatic neuropathic pain outside the trigeminal system, there is no evidence for its use for PTNP within the trigeminal system.

CONCLUSION

There may be emerging evidence for treating trigeminal neuralgia with BTX-A injections; however, there is a need for future clinical studies of therapeutic PNBs in orofacial pain conditions.

Intravenous fosphenytoin therapy for rescue of acute trigeminal neuralgia crisis in patients awaiting neurosurgical procedures: A cross-sectional study

Few treatments exist for acute attacks of trigeminal neuralgia. Therefore, this study aimed to investigate the efficacy and safety of an intravenous fosphenytoin therapy protocol in a trigeminal neuralgia crisis. We conducted a single-center, retrospective, observational study of the records of 20 patients with trigeminal neuralgia who received intravenous fosphenytoin therapy (15 mg/mL in normal saline at 50 mg/min for 15 min, total 750 mg) during hospitalization between September 2015 and August 2020. Serum phenytoin concentration was measured 30 min post-infusion. Pain severity was evaluated using a numerical rating scale and was analyzed for statistical significance. The mean age of the patients was 67.5 years (female, 50.0%). The median numerical rating scale score (interquartile range) of pain severity was 2.35 (0-10), 0.65 (0-5), 0.15 (0-1), 2.00 (0-8), and 4.30 (0-10) at 15, 30, and 60 min, and 12 and 24 h, respectively (p < .001); the numerical rating scale score was 10 before treatment. Reduction in pain 24 h following treatment was significant. The mean phenytoin concentration was 12.8 μg/mL 30 min post-treatment. While mild dizziness occurred in four patients, all could walk independently within 60 min. The mean age and weight of patients with mild dizziness were significantly higher and lower, respectively (p < .001), than those of other patients. These results may provide physicians with new insights into the innovative therapeutic option of intravenous fosphenytoin and contribute to advancements in treating acute trigeminal neuralgia crisis.

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

A Historical Note on the Treatment of Trigeminal Neuralgia

Trigeminal neuralgia, otherwise known under the French denomination of tic douloureux, is a chronic painful condition of a particular severity. Its descriptions are numerous and date back to centuries before. Although the anatomy of the trigeminal nerve has been well known, the pathophysiology and hence the treatment of this disease has been largely fortuitous. Disparate pharmacological and surgical approaches have been tried, some of them heralding a much-required therapeutic success. The authors make a brief description of the first sources that have systematized the disease, along with all therapies documented in a written form, especially from indexed journals of the two last centuries. Very few remnants of the previous therapies, actually considered obsolete, have survived to the proof of time; one of them relies on the possible role of the autonomic nervous system and anticholinergic therapies, later replaced from modern conservative and interventional approaches. Anticonvulsants have been, since 1940, the mainstay of the therapy, however, progressions in neurosurgery and mini-invasive procedures have substantially improved the quality of life and the prognosis of an otherwise very painful and chronic condition.

Trigeminal neuralgia: a practical guide

Trigeminal neuralgia (TN) is a highly disabling disorder characterised by very severe, brief and electric shock like recurrent episodes of facial pain. New diagnostic criteria, which subclassify TN on the basis of presence of trigeminal neurovascular conflict or an underlying neurological disorder, should be used as they allow better characterisation of patients and help in decision-making regarding medical and surgical treatments. MR imaging, including high-resolution trigeminal sequences, should be performed as part of the diagnostic work-up. Carbamazepine and oxcarbazepine are drugs of first choice. Lamotrigine, gabapentin, pregabalin, botulinum toxin type A and baclofen can be used either alone or as add-on therapy. Surgery should be considered if the pain is poorly controlled or the medical treatments are poorly tolerated. Trigeminal microvascular decompression is the first-line surgery in patients with trigeminal neurovascular conflict while neuroablative surgical treatments can be offered if MR imaging does not show any neurovascular contact or where patients are considered too frail for microvascular decompression or do not wish to take the risk.

The PATCH trial: efficacy and safety of 5% lidocaine-medicated plaster for the treatment of patients with trigeminal neuralgia: a study protocol for a multicentric, double-blind, enriched enrolment randomised withdrawal, vehicle-controlled study

INTRODUCTION

Trigeminal neuralgia (TN) is characterised by a sudden, severe, electric shock like paroxysmal pain, which is almost always associated with triggers. Carbamazepine is the first-line medical management of TN. However, side effects are common. Currently, there is no ideal treatment for TN. Since there is a known abnormality of Na+ channels in the trigger zone, 5% lidocaine-medicated plaster (LMP), which can block the Na+ channels on Aδ and C fibres, is an effective treatment method in many chronic pain conditions. A case report has found the benefit of LMP for the treatment of TN without any side effects. Whether LMP is an option for the treatment of TN is worth exploring.

METHODS AND ANALYSIS

The PATCH trial is a double-blind, enriched enrolment with randomised withdrawal, vehicle-controlled trial, aiming to explore the effects and safety of LMP in patients with TN. There is a 3-week initial open-label phase, followed by a 4-week double-blind treatment phase for responders. In the double-blind phase, patients will have to withdraw from this PATCH study if they meet one of the following criteria for treatment failure such as: >50% increase in pain intensity or paroxysms, lack of efficacy or side effects. The primary outcome will be the number of treatment failures. Adverse events will also be monitored throughout the study.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Institutional Review Board of Beijing Tiantan Hospital (approval number: KY 2020-102-02). The results will be disseminated in international academic meetings and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04570293.

Orofacial Neuropathic Pain-Basic Research and Their Clinical Relevancies

Trigeminal nerve injury is known to cause severe persistent pain in the orofacial region. This pain is difficult to diagnose and treat. Recently, many animal studies have reported that rewiring of the peripheral and central nervous systems, non-neuronal cell activation, and up- and down-regulation of various molecules in non-neuronal cells are involved in the development of this pain following trigeminal nerve injury. However, there are many unknown mechanisms underlying the persistent orofacial pain associated with trigeminal nerve injury. In this review, we address recent animal data regarding the involvement of various molecules in the communication of neuronal and non-neuronal cells and examine the possible involvement of ascending pathways in processing pathological orofacial pain. We also address the clinical observations of persistent orofacial pain associated with trigeminal nerve injury and clinical approaches to their diagnosis and treatment.

Medical Management of Trigeminal Neuralgia

Background

Trigeminal neuralgia (TN) is a painful condition, often leading to poor quality of life.

Objective

The aim of this review was to discuss the various treatment modalities for the medical management of TN.

Materials and Methods

We reviewed the available literature on TN in clinical databases including PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews, with a specific focus on the pharmacological treatment and newer drugs under development for the treatment of TN.

Results

Carbamazepine (CBZ) is the gold standard of treatment for TN. The first-line drugs for the treatment of TN are CBZ and oxcarbazepine (OXC). A proportion of cases (30%) are initially resistant to the first-line drugs. Alternative drugs need to be considered if the first-line drugs are not well tolerated or become ineffective with prolonged therapy. The second-line drugs comprise lamotrigine, baclofen, gabapentin, and pregabalin used as monotherapy or in combination with CBZ/OXC. Botulinum toxin A may be a promising presurgical option. Newer drug like vixotrigine has shown good results in phase two randomized control trials. About 50% of cases develop treatment resistance to oral drugs over the subsequent years of therapy and require surgical options.

Conclusion

The first-line drugs for the treatment of TN (irrespective of the age group or type) are CBZ and OXC. Combination therapy with second-line or other drugs may become necessary with poor response to CBZ/OXC, or if adverse events occur. Patients should be offered surgical options if there is poor response or tolerance to the medical therapy.

c-Abl-p38 signaling pathway mediates dopamine neuron loss in trigeminal neuralgia

Trigeminal neuralgia is a common neuropathic pain in the head and face. The pathogenesis of trigeminal neuralgia is complex, and so far, the pathogenesis of trigeminal neuralgia involving peripheral and central nervous inflammation theory has not been explained clearly. The loss of dopamine neurons in striatum may play an important role in the development of trigeminal nerve, but the reason is not clear. C-Abl is a nonreceptor tyrosine kinase, which can be activated abnormally in the environment of neuroinflammation and cause neuron death. We found that in the rat model of infraorbital nerve ligation trigeminal neuralgia, the pain threshold decreased, the expression of c-Abl increased significantly, the downstream activation product p38 was also activated abnormally and the loss of dopamine neurons in striatum increased. When treated with imatinib mesylate (STI571), a specific c-Abl family kinase inhibitor, the p38 expression was decreased and the loss of dopaminergic neurons was reduced. The mechanical pain threshold of rats was also improved. In conclusion, c-abl-p38 signaling pathway may play an important role in the pathogenesis of trigeminal neuralgia, and it is one of the potential targets for the treatment of trigeminal neuralgia.

Cranial Neuralgias

PURPOSE OF REVIEW

This article discusses the differential diagnosis, evaluation, and management of trigeminal neuralgia and reviews other neuralgias of the head and neck, including those that contribute to neuralgic ear pain.

RECENT FINDINGS

Most cases of trigeminal neuralgia are related to vascular compression, a demyelinating plaque, or a compressive mass affecting the trigeminal nerve. However, recent studies have shown that up to 11% of patients have a family history of trigeminal neuralgia, suggesting that some patients may have a genetic predisposition to demyelination or nerve hyperexcitability. In these patients, trigeminal neuralgia may occur at a younger age, on both sides of the face, or in combination with other neuralgias.

SUMMARY

When a patient presents with neuralgic pain, the diagnosis is made by careful history and neurologic examination, with attention to the dermatome involved, the triggers, and the presence of any associated sensory deficit. All patients with new neuralgia or neuropathic facial pain warrant a careful evaluation for a secondary cause. The presence of sensory deficit on bedside examination is particularly concerning for an underlying secondary etiology.

Recent Advances in Trigeminal Neuralgia and Its Management: A Narrative Review

Trigeminal neuralgia (TN) is a chronic facial pain condition that affects one or more divisions of the trigeminal nerve (5th cranial nerve). It can be idiopathic, primary, or secondary. The cornerstone of the therapy has been antiepileptic medications, peripheral nerve blocks with various neurolytic agents, and surgical procedures. With the advent of newer technologies, minimally invasive neurolytic techniques like low-level laser therapy and ozone injection have revolutionized the management of TN. Novel drugs like vixotrigine and eslicarbazepine have been promising in reducing the frequency and severity of attacks. Inhaled carbon dioxide too has shown promising results in initial trials. Neuromodulation has given robust data in controlling neuralgic pain especially refractory to medical management. Pulsed radiofrequency has been used with increasing success and the side effects like dysesthesia and paresthesia are less. Cryotherapy, neural prolotherapy, and fiber knife techniques have helped us believe that TN can be controlled and cured. The need of the hour is to develop and explore newer modalities for trigeminal neuralgia treatment with minimum side effects. In this narrative review, we have tried to shed light into the newer modalities of treatment of TN along with new clinical classification for better disease recognition and management.

Recent Advances of Magnetic Resonance Neuroimaging in Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a disease of unclear pathogenesis. It has a low incidence and is not fatal, but it can cause afflicted patients' depression or suicide. In the past, neurovascular compression was considered to be the main cause of TN, but recent studies have found that neurovascular contact is also common in asymptomatic patients and the asymptomatic side in symptomatic patients. This indicates that the neurovascular contact is not, or is only to a lesser extent, a factor in the development of TN. Thus, the study of the peripheral branches of the trigeminal nerve is necessary to understand the etiology of TN. With the development of imaging technology and the emergence of various imaging modalities, it is possible to study the etiology of TN and the pathological changes of related structures by magnetic resonance neuroimaging. This article reviews the recent advances in magnetic resonance neuroimaging of the trigeminal nerve.

Beyond its anti-migraine properties, sumatriptan is an anti-inflammatory agent: A systematic review

Sumatriptan is the first available medication from triptans family that was approved by the U.S. Food and Drug Administration for migraine attacks and cluster headaches in 1991. Most of its action is mediated by selective 5-HT_1B/1D receptor agonism. Recent investigations raised the possibility of repositioning of this drug to other indications beyond migraine, as increasing evidence suggests for an anti-inflammatory property of sumatriptan. We performed a literature search using PubMed, Web of Science, Scopus, and Google Scholar using "inflammation AND sumatriptan" or "inflammation AND 5HT1B/D" as the keywords. Then, articles were screened for their relevance and those directly discussing the correlation between inflammation and sumatriptan or 5HT1B/D were included. Total references reviewed or inclusion/exclusion were 340 retrieved full-text articles (n = 340), then based on critical assessment 66 of them were included in this systematic review. Our literature review indicates that at low doses, sumatriptan can reduce inflammatory markers (e.g., interleukin-1β, tumor necrosis factor-α, and nuclear factor-κB), affects caspases and changes cells lifespan. Additionally, nitric oxide synthase and nitric oxide signaling seem to be regulated by this drug. It also inhibits the release of calcitonin gene-related peptide. Sumatriptan protects against many inflammatory conditions including cardiac and mesenteric ischemia/reperfusion, skin flap, pruritus, peripheral, and central nervous system injuries such as spinal cord injury, testicular torsion-detorsion, oral mucositis, and other experimental models. Considering the safety and potency of low dose sumatriptan compared to corticosteroids and other immunosuppressive medications, it is worth to take advantage of sumatriptan in inflammatory conditions.

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.

Invasive and Non-Invasive Electrical Neuromodulation in Trigeminal Nerve Neuralgia: A Systematic Review and Meta-Analysis

BACKGROUND

Trigeminal neuralgia is a chronic disease characterized by intense facial pain that is caused by trigeminal nerve affectation. It usually affects adults from 50 years of age, and is more frequent in women. Additionally, it presents serious psychological effects that often lead to depression, which is why it is considered highly disabling. The therapeutic approach is based on the modification of nerve activity through electrical, surgical or chemical stimulation in specific regions of the nervous system.

OBJECTIVE

To perform a meta-analysis of the scientific literature related to invasive and non-invasive electrical neuromodulation of trigeminal neuralgia, in order to assess their effects over pain and adverse effects.

METHODS

A literature search was conducted in 4 databases, followed by a manual search of articles on invasive or non-invasive electrical neuromodulation to control the pain of trigeminal neuralgia, including the last 15 years.

RESULTS

Regarding non-invasive methods, clinical trials did not present enough results in order to perform a meta-analysis. Regarding invasive methods, clinical trials meta-analysis showed no statistical differences between different treatment methods. In all cases, improvements in patients' pain were reported, although results regarding adverse effects were variable.

CONCLUSION

In the treatment of trigeminal neuralgia, the continuous radiofrequency provides better short and medium-term results, but pulsed radiofrequency shows less adverse effects after treatment, and has better results in the long-term.

[Trigeminal neuralgia : Modern diagnostic workup and treatment]

The present article gives an update of relevant aspects in the diagnosis and therapy of trigeminal neuralgia from the neurological, neuroradiological and neurosurgical point of view. The diagnosis of trigeminal neuralgia is clinical, but high-quality imaging is mandatory to identify secondary causes and a neurovascular contact. New methods such as DTI (diffusion tensor imaging) allow a more differentiated assessment of the consequences of a vascular contact on the trigeminal nerve. Carbamazepine and oxcarbazepine continue to be first choice for the medical treatment, but have been supplemented by additional options such as pregabaline, lamotrigine, and onabotulinumtoxin A. In patients insufficiently responding to medical treatment, there are neurosurgical treatment options giving very good results. The best long-term results have been described for microvascular decompression, but percutaneous and radiosurgical treatments also are good options, especially in patients with an increased surgical risk profile, in secondary trigeminal neuralgia, and in case of recurrence after microvascular decompression.

Advances in diagnosis, classification, pathophysiology, and management of trigeminal neuralgia

Trigeminal neuralgia is a very painful neurological condition with severe, stimulus-evoked, short-lasting stabbing pain attacks in the face. The past decade has offered new insights into trigeminal neuralgia symptomatology, pathophysiology, and treatment, leading to a change in the classification of the condition. An accurate diagnosis is crucial because neuroimaging interpretation and clinical management differ among the various forms of facial pain. MRI using specific sequences should be a part of the diagnostic workup to detect a possible neurovascular contact and exclude secondary causes. Demonstration of a neurovascular contact should not be used to confirm a diagnosis but rather to facilitate surgical decision making. Carbamazepine and oxcarbazepine are drugs of first choice for long-term treatment, whereas microvascular decompression is the first-line surgery in medically refractory patients. Advances in neuroimaging techniques and animal models will provide further insight into the causes of trigeminal neuralgia and its pathophysiology. Development of more efficacious treatment options is highly warranted.

Clinical efficacy of MVD combined with PSR in the treatment of primary trigeminal neuralgia

Clinical efficacy of microvascular decompression (MVD) combined with percutaneous stereotactic radiofrequency rhizotomy (PSR) in the treatment of primary trigeminal neuralgia was investigated. The medical records of 141 patients with primary trigeminal neuralgia admitted to Shandong Provincial Hospital from May 2011 to June 2013 were collected. Among them, 63 patients received MVD surgery and were set as group A, while the other 78 received MVD combined with PSR and were as group B. The efficacy and complication of the two treatment methods were compared. Multivariate logistic regression was performed to analyze the risk factors for treatment efficacy. The total effective rate was 96.15% in group B, higher than that in group A (88.89%), but the difference was not statistically significant (P>0.05). The complications in group B were statistically less than that in group A (P<0.05). Risk factors for the onset of primary trigeminal neuralgia included the degree of decompression, duration of disease, degree of compression, and clinical symptoms. Patients treated with MVD combined with PSR had a better quality of life and lower 5-year recurrence rate than patients treated with MVD (both P<0.05). In conclusion, MVD combined with PSR treatment has good clinical efficacy in primary trigeminal neuralgia and low incidence of complications. The possible risk factors for the onset of primary trigeminal neuralgia include the degree of decompression, duration of disease, degree of compression, and clinical symptoms.

The fifth cranial nerve in headaches

The fifth cranial nerve is the common denominator for many headaches and facial pain pathologies currently known. Projecting from the trigeminal ganglion, in a bipolar manner, it connects to the brainstem and supplies various parts of the head and face with sensory innervation. In this review, we describe the neuroanatomical structures and pathways implicated in the sensation of the trigeminal system. Furthermore, we present the current understanding of several primary headaches, painful neuropathies and their pharmacological treatments. We hope that this overview can elucidate the complex field of headache pathologies, and their link to the trigeminal nerve, to a broader field of young scientists.