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.

Trigeminal Neuralgia as a Primary Demyelinating Disease: Potential Multimodal Evidence and Remaining Controversies

Trigeminal neuralgia is a heterogeneous disorder with likely multifactorial and complex etiology; however, trigeminal nerve demyelination and injury are observed in almost all patients with trigeminal neuralgia. The current management strategies for trigeminal neuralgia primarily involve anticonvulsants and surgical interventions, neither of which directly address demyelination, the pathological hallmark of trigeminal neuralgia, and treatments targeting demyelination are not available. Demyelination of the trigeminal nerve has been historically considered a secondary effect of vascular compression, and as a result, trigeminal neuralgia is not recognized nor treated as a primary demyelinating disorder. In this article, we review the evolution of our understanding of trigeminal neuralgia and provide evidence to propose its potential categorization, at least in some cases, as a primary demyelinating disease by discussing its course and similarities to multiple sclerosis, the most prevalent central nervous system demyelinating disorder. This proposed categorization may provide a basis in investigating novel treatment modalities beyond the current medical and surgical interventions, emphasizing the need for further research into demyelination of the trigeminal sensory pathway in trigeminal neuralgia. PERSPECTIVE: This article proposes trigeminal neuralgia as a demyelinating disease, supported by histological, clinical, and radiological evidence. Such categorization offers a plausible explanation for controversies surrounding trigeminal neuralgia. This perspective holds potential for future research and developing therapeutics targeting demyelination in the condition.

Sex differences in trigeminal neuralgia: a focus on radiological and clinical characteristics

BACKGROUND

It is well established that trigeminal neuralgia is more prevalent in females than in males. Neurovascular compression with morphological changes of the trigeminal root represents the most recognized etiological factor. However, other factors may play a role in the framework of a multi-hit model. The primary aim of this study was to investigate sex differences in radiological and clinical characteristics of trigeminal neuralgia to better understand the multifactorial origin of this peculiar neuropathic pain condition.

METHODS

In this cross-sectional study patients with a definite diagnosis of primary trigeminal neuralgia were consecutively enrolled. Each patient underwent 3T MRI with sequences dedicated to the study of neurovascular compression. Major morphological changes of the trigeminal root were quantitatively assessed. Clinical characteristics were systematically collected through a dedicated questionnaire. A logistic regression model was implemented to predict radiological and clinical characteristics based on sex.

RESULTS

A total of 114 patients with classical (87) or idiopathic trigeminal neuralgia (27) were enrolled. Female sex was predictive for idiopathic trigeminal neuralgia. Male sex was predictive, among the comorbidities and clinical characteristics, for hypertension, the involvement of the left side and the second trigeminal division, alone or with the ophthalmic division.

DISCUSSION

The preponderance of TN in the female sex and the association between idiopathic TN and the female sex suggest the role of additional etiological factors in the framework of a multi-hit model. The identification of clinical variables predicted by sex suggests the possibility that distinct phenotypes, with peculiar pathophysiological and therapeutic aspects, may occur in females and males.

A Systematic Review of the Role of Magnetic Resonance Imaging in the Diagnosis and Detection of Neurovascular Conflict in Patients With Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a debilitating disorder causing severe, episodic, unilateral stabbing facial pain disturbing enough to disrupt the activities of daily life. Classic TN is caused due to compression injury of the trigeminal nerve at the cistern segment caused by either an artery or a vein, referred to as neurovascular contact or conflict (NVC). Magnetic resonance imaging (MRI) has been the standard tool for the diagnosis of NVC. This study aimed to determine the incidence of NVC in TN, as identified by MRI, assess the various MRI grading patterns among patients with TN, and identify the vessels primarily involved in NVC. A systematic search of studies that used MRI for the diagnosis of TN in reference to NVC was conducted on DOAJ and PubMed/PubMed Central. Data were extracted and entered into a Microsoft Excel spreadsheet. The outcomes measured were the incidence of NVC as shown in MRI, vessels involved in NVC, and MRI grading patterns. We identified and selected 20 studies that fulfilled inclusion/exclusion criteria. In total, 1,436 patients were enrolled in all included studies. The type of MRI used was 1.5 T or 3 T MRI. The mean age of the patients varied from 49 to 63 years, with an equivalent male-to-female ratio. NVC was seen in 1,276 cases out of 1,436 cases (88.85%) of TN on the ipsilateral side, as shown by MRI. The vessels involved were arteries in 80-90% of the cases, followed by veins. Among the arteries, the superior cerebellar artery was the most common artery (80-90% of cases). The grades of NVC as assessed by MRI included grades I, II, and III with varied proportions in different studies. NVC is a common problem in TN, wherein there is compression at the nerve root entry zone, and it shows a strong predilection for the elderly population. MRI seems to be a novel imaging diagnostic investigation to identify NVC associated with TN. Moreover, NVC grading must be done with MRI so that it may help the surgeon in stratifying the patient's treatment.

Pre-operative MRI measurement of the Meckel's cave volume in percutaneous balloon compression of the trigeminal nerve

OBJECTIVE

To explore the feasibility of measuring the volume of Meckel's cave by MRI before operation and its value in guiding percutaneous balloon compression (PBC) of trigeminal nerve (TN).

METHODS

The pre-operative MRI and operative data of 31 patients, who underwent PBC of TN, were analyzed retrospectively. Axial scanning was performed using T2 weighted three-dimensional high-resolution MRI, and then coronal and sagittal images were reconstructed. Volumes of Meckel's cave were measured by two radiologists, and their consistence was assessed using intraclass correlation coefficient. Pearson and Spearman analyses were used to assess the correlations of the volumes of Meckel's cave among coronal, sagittal, and axial MRI images, and between that measured by MRI and the filling volume of operative balloon, respectively. Bland-Altman plot was used to assess their agreements.

RESULTS

There was high consistency in volumes of Meckel's cave between the two radiologists with intraclass correlation coefficient from 0.921 to 0.962. High correlations and good agreements in volumes of Meckel's cave were obtained from the three orientations, with Pearson coefficients and differences of 0.96 and 0.01 ml (coronal vs sagittal), 0.95 and 0.01 ml (coronal vs axial), and 0.95 and 0.00 ml (sagittal vs axial), respectively. The moderate correlation and good agreements were also obtained between MRI and operative balloon volume (ρ = 0.448, p < 0.05; difference, 0.02 ml).

CONCLUSION

It is feasible to measure the volume of Meckel's cave by MRI before operation, and it is of guiding significance for the individual selection of balloon filling volume in PBC of TN.

ADVANCES IN KNOWLEDGE

This is the first study to investigate the relationships between the three-dimensional high resolution MRI images and the clinical volume of Meckel's cave. The high-resolution MRI method can help guide PBC of TN.

Efficiency and Efficacy of Real-Time Fluoroscopic Image-Guided Percutaneous Gasserian Glycerol Rhizotomy (PGGR), for Intractable Cases of Trigeminal Neuralgia

Aim & Objectives

To evaluate the ease, efficiency, effectiveness, and associated complications of the technique of percutaneous Gasserian glycerol rhizotomy (PGGR) under real-time fluoroscopic image guidance, for management of severe and refractory cases of primary trigeminal neuralgia, in medical compromised patients. To also assess the long-term efficacy and the necessity, if any, for repeat procedures to salvage recurrences.

Study Design & Setting

In a prospective study conducted at a single institution over a period of three years, 25 cases of Idiopathic Trigeminal Neuralgia refractory to conservative modalities of treatment including medication were managed with PGGR under real-time fluoroscopic image guidance. All the 25 patients included in this study were known surgical risks for relatively invasive treatment procedures, owing to factors such as advanced age and/or presence of co-morbidities.

Material & Methods

In order to minimize the risks related to the conventional techniques of Trigeminal root rhizotomy based on cutaneous landmarks alone, and to eliminate the need for frequent repositioning of the needle/cannula, we adopted a technique of real-time fluoroscopic image-guided negotiation of a 22 gauge (0.7 mm dia), 10-cm-long spinal nerve block needle through the foramen ovale, to reach the trigeminal cistern within the Meckel's cave. The efficiency of the technique was assessed in terms of time taken, effort, and ease in performing it. Associated intra- and post-procedural complications were recorded. The immediate and long-term effectiveness of the procedure was evaluated by analysing the degree and duration of pain control achieved, time to recurrence, and the necessity for repeat procedures.

Results & Conclusion

There were nil intra- or post-procedural complications encountered, and no failures associated with this procedure. Real-time fluoroscopic imaging enabled easy, quick, and successful negotiation of the nerve-block needle through the Foramen Ovale, so as to reach the Trigeminal cistern within the Meckel's cave, within 11 min on an average. An immediate and long lasting post-procedural pain relief was achieved in all the patients. During the follow-up period of 36 months, recurrence of pain was observed in six cases, the mean timing of the recurrence being 26 months or more. Five of these cases were manageable with medication alone, and only one required a repeat procedure. These results indicate that PGGR under real-time fluoroscopic image guidance is a safe, simple, time-efficient, convenient, efficacious, reliable, and minimally invasive means of treating refractory and intractable cases of trigeminal neuralgia.

Microvascular decompression in trigeminal neuralgia - a prospective study of 115 patients

Background

Trigeminal neuralgia is a severe facial pain disorder. Microvascular decompression is first choice surgical treatment of patients with classical TN. There exist few prospective studies with an independent evaluation of efficacy and complications after MVD.

Objectives

We aimed to assess outcome and complications after microvascular decompression from our center.

Methods

We prospectively recorded clinical characteristics, outcome, and complications from consecutive patients with either classical or idiopathic (only patients with a neurovascular contact) trigeminal neuralgia undergoing microvascular decompression. Neurovascular contact was evaluated by 3.0 Tesla MRI. Patients were assessed before and 3, 6, 12, and 24 months after surgery by independent assessors.

Results

Of 115 included patients, 86% had a clinically significant outcome (i.e., BNI I – BNI IIIb). There was a significant association between an excellent surgical outcome and the male sex (OR 4.9 (CI 1.9–12.8), p = 0.001) and neurovascular contact with morphological changes (OR 2.5 (CI 1.1–6.0), p = 0.036). Significantly more women (12/62 = 19%) than men (2/53 = 4%) had a failed outcome, p = 0.019. The most frequent major complications were permanent hearing impairment (10%), permanent severe hypoesthesia (7%), permanent ataxia (7%), and stroke (6%). Most patients (94%) recommend surgery to others.

Conclusion

Microvascular decompression is an effective treatment for classical and idiopathic (only patients with a neurovascular contact) trigeminal neuralgia with a high chance of a long-lasting effect. The chance of an excellent outcome was highest in men and in patients with classical trigeminal neuralgia. Complications are relatively frequent warranting thorough patient evaluation and information preoperatively.

Trial registration

Clinical.trials.gov registration no. NCT04445766.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01520-x.

Global Trends and Hotspots in Trigeminal Neuralgia Research From 2001 to 2021: A Bibliometric Analysis

Background

In recent years, there have been an increasing number of studies on trigeminal neuralgia (TN). However, a scientific and comprehensive study of the current situation and trends in the field of TN research is lacking. The purpose of this study is to summarize and visualize the development, research hotspots, and future trends in TN based on a bibliometric approach.

Methods

Studies on TN published from 2001 to 2021 were obtained from the Web of Science Core Collection (WoSCC). Bibliometrics, CiteSpace, and VOSviewer tools were used for bibliometric analysis and visualization.

Results

In total, 4,112 documents were searched. The number of research articles in the field is generally on an upward trend, with the fastest growth in the number of articles from 2017 to 2020. Shanghai Jiao Tong University, Pittsburgh University, and Mayo Clinic are the three institutions with the most publications. Shiting Li and Zakrzewska JM are the most prolific author and top co-cited authors, respectively. The Journal of Neurosurgery is the most influential journal. The top 5 keywords in that time frame are TN, microvascular decompression, facial pain, stereotactic radiosurgery, and neuropathic pain.

Conclusion

This is the first comprehensive scientific bibliometric analysis of the global research field on TN over the past 21 years, providing a meaningful reference for further exploration of topical issues and research trends in the field.

[A rare form of secondary orofacial pain: Herzenberg's disease]

A clinical analysis of a patient with a rare form of secondary facial pain (Herzenberg's disease) is presented. The conducted research and pharmacological tests made it possible to exclude such diseases as trigeminal neuralgia, stylohyoid syndrome, TMJ pain dysfunction, dental plexalgia, myofascial facial pain syndrome. The patient is consulted by a dental surgeon to exclude pathology of the parotid salivary gland and sialolithiasis. The patient was treated with broad-spectrum antibiotics for 8 days. Also, supportive therapy was prescribed: desensitizing, vitamins, as well as an anxiolytic and an antidepressant in minimum therapeutic doses for a course of 14 days (with subsequent correction of the dosage and duration of administration) to correct the emotional state of the patient. We recommend a gentle diet (alkaline warm drink, soft food), and a diet that does not provoke salivation. Locally it was recommended to rinse with antimicrobial drugs, phonophoresis, electrophoresis, magnetotherapy. On the 6^th day of therapy, the therapeutic effect was obtained. By the 14^th day of therapy, the pain syndrome was leveled.

The changing face of trigeminal neuralgia-A narrative review

OBJECTIVE

This narrative review aims to update the reader on the new classification of trigeminal neuralgia (TN), clinical signs, pathophysiologic evidence, and their implications on management. This review is based on the authors' collective experience and knowledge of the literature in addition to a literature search.

BACKGROUND

In recent years, the phenotype of TN has been intensively studied leading to discrete groups of patients. These include patients with TN with additional continuous pain, and patients with and without neurovascular compression of the trigeminal dorsal root entry zone. A number of associated clinical signs such as tearing and sensory changes need further research.

METHODS

The literature on TN was searched in PubMed with the aims of providing evidence for the recently published third edition of the International Classification of Headache Disorders (ICHD) and update the clinical phenotype and management of the TN subcategories.

RESULTS

The ICHD's new classification for TN is based on reliable clinical data, imaging, and neurophysiologic studies. The TN classification reflects current knowledge and has improved the possibility for clinicians to choose adequate management options. However, there is a lack of effective, safe drugs for the management of TN and sparse, robust data on neurosurgical options.

CONCLUSION

Research into all aspects of TN-diagnosis, pharmacotherapy, surgery, long-term management prognosis, and natural history-is needed. Research should adhere to the ICHD's schema for TN. Improved drugs are needed along with rigorous research into surgical options and their efficacy for different subtypes of TN.

Neurovascular contact plays no role in trigeminal neuralgia secondary to multiple sclerosis

INTRODUCTION

A demyelinating plaque and neurovascular contact with morphological changes have both been suggested to contribute to the etiology of trigeminal neuralgia secondary to multiple sclerosis (TN-MS). The aim of this study was to confirm or refute whether neurovascular contact with morphological changes is involved in the etiology of TN-MS.

METHODS

We prospectively enrolled consecutive TN-MS patients from the Danish Headache Center. Clinical characteristics were collected systematically. MRI scans were done using a 3.0 Tesla imager and were evaluated by the same experienced blinded neuroradiologist.

RESULTS

Sixty-three patients were included. Fifty-four patients were included in the MRI analysis. There was a low prevalence of neurovascular contact with morphological changes on both the symptomatic side (6 (14%)) and the asymptomatic side (4 (9%)), p = 0.157. Demyelinating brainstem plaques along the trigeminal afferents were more prevalent on the symptomatic side compared to the asymptomatic side (31 (58%) vs. 12 (22%), p < 0.001). A demyelinating plaque was highly associated with the symptomatic side (odds ratio = 10.6, p = 0.002).

CONCLUSION

The primary cause of TN-MS is demyelination along the intrapontine trigeminal afferents. As opposed to classical trigeminal neuralgia, neurovascular contact does not play a role in the etiology of TN-MS. Microvascular decompression should generally not be offered to patients with TN-MS.The study was registered at ClinicalTrials.gov (number NCT04371575).

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.

Trigeminal Neuralgia

Trigeminal neuralgia is one of the most severe facial pains that patients can experience. This unpredictable, episodic pain, mostly unilateral in the distribution of the trigeminal nerve, results in recurrent shooting pain lasting for seconds to minutes. It is light touch provoked and therefore prevents patients from eating and touching their face, and so has a significant impact on quality of life. Patients often consult a dentist because it usually presents like dental pain. Dentists need to avoid irreversible dental treatment. Response to carbamazepine is good but tolerability is poor. Surgical options are available and are generally successful. Patients can gain further information from a patient support group, such as Trigeminal Neuralgia Association UK.

CPD/Clinical Relevance: Although rare, trigeminal neuralgia patients often present to dentists who therefore need to recognize it as a non-dental cause of pain in order to avoid irreversible dental treatment.

Diffusion tensor imaging of microstructural alterations in the trigeminal nerve due to neurovascular contact/compression

BACKGROUND

Several recent studies have focused on microstructural changes in the trigeminal nerve in trigeminal neuralgia using diffusion tensor imaging (DTI). However, alterations after microvascular decompression (MVD) have rarely been investigated. Furthermore, the trigeminal nerve of asymptomatic individuals also presenting with neurovascular contact/compression (NVC) has not yet been studied.

METHODS

Thirty-four patients suffering from trigeminal neuralgia and 34 healthy age-matched controls, who were identified as having unilateral NVC signs, underwent both DTI and high-resolution magnetic resonance imaging (MRI) for comparison. All trigeminal neuralgia patients underwent a post-surgical MRI scan after 7 days and a follow-up MRI scan within 6-8 months after surgery. The apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) values were measured from coronal images in which the nerves from the root exit point to the distal segment were clearly shown.

RESULTS

In 34 trigeminal neuralgia patients, the absolute FA value was significantly lower on the affected side (mean FA, 0.34 ± 0.03) than on the unaffected side (mean FA, 0.37 ± 0.05, p < 0.001). The FA ratio was also significantly different between the trigeminal neuralgia group (Rs_FA, 0.92 ± 0.06) and the control group (Rs_FA, 0.99 ± 0.09) (p = 0.001). The absolute ADC value between the two sides in patients and the ratios of ADC between the trigeminal neuralgia and control groups did not show any significant differences (p = 0.21 and 0.29, respectively). However, in 34 healthy subjects presenting with signs of NVC, neither the FA value nor the ADC showed a difference between sides (p > 0.05). The FA ratio of patients showed a significant increase on two follow-up MRI scans compared to the preoperative FA (p = 0.02 and 0.002, respectively), while the ADC ratio showed a significant decrease at 6 months after MVD (p = 0.004).

CONCLUSION

This study of trigeminal neuralgia due to NVC found that DTI indexes could reflect alterations in the affected trigeminal nerve. Furthermore, a reversible change after MVD surgery could be potentially valuable for monitoring the change in white matter of the trigeminal nerve.

Trigeminal Neuralgia and Charcot-Marie-Tooth Disease: An Intriguing Association. Lessons From a Large Family Case Report and Review of Literature

We report a case of familial trigeminal neuralgia (TN) and Charcot-Marie-Tooth disease (CMT) caused by an identified MPZ mutation with a review of previous cases described in the literature.

BACKGROUND

The association of TN in CMT patients has previously been reported in a few cases. The pathophysiological link can be detailed with recent use of genetic analysis in CMT.

METHODS

We report a large family including 7 members affected by CMT, 4 of whom also presented with TN. We then performed a literature review of literature by search of Pubmed from 1950 to September 2018, using the search terms "trigeminal neuralgia" and "Charcot-Marie-Tooth" and the references of relevant articles.

RESULTS

Overall, we found 29 previously published TN cases in 12 CMT families. Among them, only 7 families (69%) included several affected members, suggesting that not all mutations involved in CMT predispose to TN. TN in this context seems to present with specific characteristics, including earlier age of onset, bilateral presentation, and poor tolerance to preventive treatments with gait disturbance exacerbated by the underlying neuropathy.

CONCLUSION

This report of familial TN in CMT with identified MPZ mutation highlighted specific characteristics of this association. Considered as a rare association in the literature, it may be underestimated and the clinician should be aware of its specific pattern, including earlier age of onset, bilateral presentation, and poor tolerance to preventive treatments.

Favourable prognosis of trigeminal neuralgia when enrolled in a multidisciplinary management program - a two-year prospective real-life study

BACKGROUND

Prognosis of medically treated trigeminal neuralgia patients is assumed to be poor, but the evidence is lacking. Thus, prospective real-life studies of medical management of trigeminal neuralgia are warranted.

METHODS

This was an observational study. Patients were consecutively enrolled in a structured management program at a specialist centre for facial pain. Optimisation of medical treatment, physiotherapy, psychotherapy, and advice from trained nurses, were parts of the program. Medically intractable patients were referred for neurosurgery. Data-collection was prospective using standardised schemes and patient surveys. The aim was to describe the two-year outcome of medical treatment at the specialist centre. The primary outcome was a 50% reduction in the overall burden of pain according to a Numerical Rating Scale (NRS) after two years.

RESULTS

A total of 186 primary TN patients were enrolled in the program of which 103 patients remained medically managed and completed the two-year follow-up. Fifty patients were treated surgically within the first two years of follow-up. Half of the medically managed patients (53 (51%)), had more than a 50% reduction in the overall burden of pain over the two-year period. The overall burden of pain on NRS decreased from mean 5.34 to 3.00, p < 0.01. There was no significant association between primary outcome and sex, depression and/or anxiety, concomitant persistent pain, or neurovascular contact with morphological changes of the trigeminal nerve.

CONCLUSIONS

Patients with trigeminal neuralgia improve over a two-year period when enrolled in a structured medical management program. Optimisation of drug treatment, continuous advice and education and support by the multidisciplinary team, referral of the medically intractable patients for surgery or the natural history of the disease, can be some of the reasons for the improvement. The favourable prognosis provides hope and optimism for medically managed TN patients.

TRIAL REGISTRATION

Current study was observational, and patients were offered standard clinical care and laboratory workups according to current American Academy of Neurology and European Federation of Neurological Societies treatment guidelines. The study has been registered at ClincalTrials.gov. ID: NCT03838393 .

Current and Innovative Pharmacological Options to Treat Typical and Atypical Trigeminal Neuralgia

Trigeminal neuralgia is a representative neuropathic facial pain condition, characterised by unilateral paroxysmal pain in the distribution territory of one or more divisions of the trigeminal nerve, triggered by innocuous stimuli. A subgroup of patients with trigeminal neuralgia [TN (previously defined as atypical TN)] also suffer from concomitant continuous pain, i.e. a background pain between the paroxysmal attacks. The aim of this review is to provide current, evidence-based, knowledge about the pharmacological treatment of typical and atypical TN, with a specific focus on drugs in development. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews and the Clinical Trials database (ClinicalTrials.gov), taking into account publications up to February 2018. Two authors independently selected studies for inclusions, data extraction, and bias assessment. Carbamazepine and oxcarbazepine are the first-choice drugs for paroxysmal pain. When sodium channel blockers cannot reach full dosage because of side effects, an add-on treatment with lamotrigine or baclofen should be considered. In patients with atypical TN, both gabapentin and antidepressants are expected to be efficacious and should be tried as an add-on to oxcarbazepine or carbamazepine. Although carbamazepine and oxcarbazepine are effective in virtually the totality of patients, they are responsible for side effects causing withdrawal from treatment in an important percentage of cases. A new, better tolerated, Nav1.7 selective state-dependent, sodium channel blocker (vixotrigine) is under development. Future trials testing the effect of combination therapy in patients with TN are needed, especially in patients with concomitant continuous pain and in TN secondary to multiple sclerosis.

Prognostic factors for outcome of microvascular decompression in trigeminal neuralgia: A prospective systematic study using independent assessors

Introduction

There is a lack of high-quality prospective, systematic studies using independent assessors of outcome of microvascular decompression as treatment for trigeminal neuralgia.

Methods

Clinical characteristics and outcome data were recorded prospectively from consecutive classical trigeminal neuralgia patients, using standardized interviews. Degree of neurovascular contact was evaluated by a 3.0 Tesla MRI blinded to symptomatic side. Patients were assessed before and 12 months after surgery by a neurologist.

Results

Twenty-six men and 33 women completed 12 months follow-up. Forty-one patients (69%) had an excellent outcome (no pain, no medication). Ten (18%) patients had a good outcome. Eight (12%) patients had no improvement or had worsening of pain. MRI showed neurovascular contact with morphological changes in 34 patients (58%). Odds ratio between neurovascular contact with morphological changes and excellent outcome was 4.4 (Cl 1.16–16.26), p = 0.029. Odds ratio between male sex and excellent outcome was 11.38 (Cl 2.12–59.52), p = 0.004. No significant association was found between excellent outcome and concomitant persistent pain, current age or disease duration.

Conclusion

Neurovascular contact with morphological changes and male sex are positive predictive factors for outcome of microvascular decompression. The findings enable clinicians to better inform patients before surgery.

Nerve atrophy in trigeminal neuralgia due to neurovascular compression and its association with surgical outcomes after microvascular decompression

BACKGROUND

Idiopathic trigeminal neuralgia (TN) is caused by neurovascular compression and is often related to morphological changes in the trigeminal nerve. The aim of this study was to quantitatively measure atrophic changes of trigeminal nerves in patients with TN, and to further investigate whether nerve atrophy affected the efficacy of microvascular decompression (MVD).

METHODS

We conducted a prospective case-control study of 60 consecutive patients with TN and 30 sex- and age-matched healthy controls. All subjects underwent high-resolution three-dimensional MRI. The volume of the cisternal segment of trigeminal nerves was measured and compared using 3D Slicer software. Patients with TN underwent primary MVD and regular follow-up for at least 2 years. Associations of nerve atrophy with patient characteristics and operative outcomes were analyzed.

RESULTS

The mean volume of the affected trigeminal nerve was significantly reduced in comparison to that of the nonaffected side (65.8 ± 21.1 versus 77.9 ± 19.3 mm³, P = 0.001) and controls (65.8 ± 21.1 versus 74.7 ± 16.5 mm³, P = 0.003). Fifty-two patients (86.7%) achieved complete pain relief without medication immediately after surgery, and 77.6% of patients were complete pain relief at the 2-year follow-up. The Spearman correlation test showed that there was a positive correlation (r = 0.46, P = 0.018) between the degree of trigeminal nerve indentation and nerve atrophy. In multivariate logistic regression analysis, two factors, indentation on nerve root (OR = 2.968, P = 0.022) and degree of nerve atrophy (OR = 1.18, P = 0.035), were associated with the long-term outcome.

CONCLUSIONS

TN is associated with atrophy on the affected nerve. Furthermore, greater nerve atrophy is associated with more severe trigeminal nerve indentation and better long-term outcome following MVD.

Triggering trigeminal neuralgia

Introduction Although it is widely accepted that facial pain paroxysms triggered by innocuous stimuli constitute a hallmark sign of trigeminal neuralgia, very few studies to date have systematically investigated the role of the triggers involved. In the recently published diagnostic classification, triggered pain is an essential criterion for the diagnosis of trigeminal neuralgia but no study to date has been designed to address this issue directly. In this study, we set out to determine, in patients with trigeminal neuralgia, how frequently triggers are present, which manoeuvres activate them and where cutaneous and mucosal trigger zones are located. Methods Clinical characteristics focusing on trigger factors were collected from 140 patients with trigeminal neuralgia, in a cross-sectional study design. Results Provocation of paroxysmal pain by various trigger manoeuvres was reported by 136 of the 140 patients. The most frequent manoeuvres were gentle touching of the face (79%) and talking (54%). Trigger zones were predominantly reported in the perioral and nasal region. Conclusion This study confirms that in trigeminal neuralgia, paroxysmal pain is associated with triggers in virtually all patients and supports the use of triggers as an essential diagnostic feature of trigeminal neuralgia.

Computed Tomography in the Diagnosis of Classical Trigeminal Neuralgia

OBJECTIVE

This study aims to characterize the pathogenesis of neurovascular conflict in trigeminal neuralgia (TN) with the goal of producing a reliable diagnostic method.

METHODS

Data were obtained during microvascular decompression surgery. The normal relationship between the superior cerebellar artery (SCA) and the trigeminal nerve root also was characterized in postmortem cases. Furthermore, SCA was imaged with high-resolution computed tomography angiography.

RESULTS

Our results indicate that contact between SCA and the trigeminal nerve root is present in both TN and non-TN cases, but in patients with TN, the apex of SCA loop was always at the bottom of the upper edge of the trigeminal root forming the state of neurovascular conflict. High-resolution angiography supported the intraoperative results.

CONCLUSIONS

These findings indicate a clear difference between neurovascular contact and conflict and point to the use of high-resolution computed tomography visualization of the position of SCA loop apex relative to the trigeminal nerve root as a primary diagnostic method.

Trigeminal neuralgia - diagnosis and treatment

Introduction Trigeminal neuralgia (TN) is characterized by touch-evoked unilateral brief shock-like paroxysmal pain in one or more divisions of the trigeminal nerve. In addition to the paroxysmal pain, some patients also have continuous pain. TN is divided into classical TN (CTN) and secondary TN (STN). Etiology and pathophysiology Demyelination of primary sensory trigeminal afferents in the root entry zone is the predominant pathophysiological mechanism. Most likely, demyelination paves the way for generation of ectopic impulses and ephaptic crosstalk. In a significant proportion of the patients, the demyelination is caused by a neurovascular conflict with morphological changes such as compression of the trigeminal root. However, there are also other unknown etiological factors, as only half of the CTN patients have morphological changes. STN is caused by multiple sclerosis or a space-occupying lesion affecting the trigeminal nerve. Differential diagnosis and treatment Important differential diagnoses include trigeminal autonomic cephalalgias, posttraumatic or postherpetic pain and other facial pains. First line treatment is prophylactic medication with sodium channel blockers, and second line treatment is neurosurgical intervention. Future perspectives Future studies should focus on genetics, unexplored etiological factors, sensory function, the neurosurgical outcome and complications, combination and neuromodulation treatment as well as development of new drugs with better tolerability.

Case Studies of Uncommon and Rare Headache Disorders

The following 6 case studies are presented: a 12-day migraine with recurring aura?; a migraineur with a new constant headache for 1 month; an orthostatic headache; a unilateral headache; migraine with aura and limb pain without headache; and nocturnal headaches. These cases illustrate the fascinating diversity and challenges of primary and secondary headaches that neurologists commonly encounter.

Pre-operative declining proportion of fractional anisotropy of trigeminal nerve is correlated with the outcome of micro-vascular decompression surgery

Background

Type 2 trigeminal neuralgia (TN) is an intractable neuropathic pain syndrome compared with type 1 TN because of the difficulty of diagnosis as well as the unsatisfactory prognosis. Neurovascular compression (NVC) is considered the major pathology of TN. Routine magnetic resonance imaging (MRI) sequences are inadequate for revealing the effect of NVC which is related to the surgical decision and outcome. The decreasing of fractional anisotropy (FA), one of the MRI diffusion tensor imaging (DTI) metrics, is correlated with the demyelination of trigeminal nerve (TGN) that reveal the severity of NVC.

Methods

A retrospective review of patients treated with micro-vascular decompression (MVD) surgery was undertaken. All the patients were diagnosed as type 2 TN. FA of TGN of both sides were measured. The FA declining proportion = ((the mean FA value of healthy lateral)-(the mean FA value of the symptomatic lateral))/(the mean FA value of healthy lateral). Declining proportion of FA value, discovery of surgery and outcome of MVD were recorded and analyzed. Logistic regression analysis and linear regression analysis were employed to analyze the risk factors of declining proportion of FA value and MVD outcome.

Results

Nineteen patients were assessed in our study. The average declining proportion of FA value for all patients was 0.25 ± 0.12. The average declining proportion of FA value of “success” and “failure” group was 0.32 ± 0.09 to 0.14 ± 0.10 (P = 0.002 < 0.05). The declining proportion of FA value of artery (including the artery plus vein situation) was 0.34 ± 0.06 in contrast to 0.15 ± 0.08 of vein (P = 0.000 < 0.05). MVD outcome was correlated with declining proportion of FA value (AUC = 0.900). Furthermore, declining proportion of FA value was higher in arterial compression situation.

Conclusion

FA value quantitatively showed the alteration of TGN caused by NVC. It provided direct evidence about the effect of NVC which facilitated the diagnosis and surgical decision of type 2 TN. Besides, significant reduction of FA value may predict an optimistic outcome of MVD.

Trigeminal neuralgia--a coherent cross-specialty management program

BACKGROUND

Optimal management of patients with classical trigeminal neuralgia (TN) requires specific treatment programs and close collaboration between medical, radiological and surgical specialties. Organization of such treatment programs has never been described before. With this paper we aim to describe the implementation and feasibility of an accelerated cross-speciality management program, to describe the collaboration between the involved specialties and to report the patient flow during the first 2 years after implementation. Finally, we aim to stimulate discussions about optimal management of TN.

METHODS

Based on collaboration between neurologists, neuroradiologists and neurosurgeons a standardized program for TN was implemented in May 2012 at the Danish Headache Center (DHC). First out-patient visit and subsequent 3.0 Tesla MRI scan was booked in an accelerated manner. The MRI scan was performed according to a special TN protocol developed for this program. Patients initially referred to neurosurgery were re-directed to DHC for pre-surgical evaluation of diagnosis and optimization of medical treatment. Follow-up was 2 years with fixed visits where medical treatment and indication for neurosurgery was continuously evaluated. Scientific data was collected in a structured and prospective manner.

RESULTS

From May 2012 to April 2014, 130 patients entered the accelerated program. Waiting time for the first out-patient visit was 42 days. Ninety-four percent of the patients had a MRI performed according to the special protocol after a mean of 37 days. Within 2 years follow-up 35% of the patients were referred to neurosurgery after a median time of 65 days. Five scientific papers describing demographics, clinical characteristics and neuroanatomical abnormalities were published.

CONCLUSION

The described cross-speciality management program proved to be feasible and to have acceptable waiting times for referral and highly specialized work-up of TN patients in a public tertiary referral centre for headache and facial pain. Early high quality MRI ensured correct diagnosis and that the neurosurgeons had a standardized basis before decision-making on impending surgery. The program ensured that referral of the subgroup of patients in need for surgery was standardized, ensured continuous evaluation of the need for adjustments in pharmacological management and formed the basis for scientific research.