Classical Trigeminal Neuralgia Research Articles

Long-term results of microvascular decompression with video endoscopy in the treatment of patients with atypical trigeminal neuralgia

Background: The incidence of atypical trigeminal neuralgia (aNTN) varies from 1 to 7 per 100,000 population per year. The main cause of its development is compression of the trigeminal nerve (TN) root by a vein and/or artery in the cerebellar cistern. To date, the final tactics of treatment for patients with aNTN has not been specified. The effectiveness of conservative methods of therapy does not exceed 50%.
 The aim of this study was to evaluate the results of microvascular decompression using video endoscopy in the treatment of patients with atypical trigeminal neuralgia.
 Methods: In the period from 2014 to 2021, 34 patients with aNTN were operated on, of which 18 (53%) patients had neuropathic pain (more than 4 points on the DN4 scale), and 15 (44%) patients had transformation of classical trigeminal neuralgia into atypical neuralgia. The conservative therapy (carbamazepine, gabapentin, pregabalin), administered to all the patients in the preoperative period, was not accompanied by a significant relief of pain syndrome. The maximum intensity of pain upon admission to the hospital was, according to the visual analog scale (VAS), 10 points, according to the BNI (Barrow Neurological Institute) Pain Intensity Scale V (severe, persistent pain). All the patients underwent microvascular decompression of the trigeminal nerve root with the use of Teflon; in 12 (35%) patients, in addition to microscopy, video endoscopy was used. The average follow-up period after the surgery was 3.41.7 years (from 1 to 5 years).
 Results: In all (100%) patients, the pain was completely eliminated (BNI I) after the surgery. A total five-year excellent and good outcome of the disease on the J. Miller and BNI scale (I -II) was noted in 80% (n=27) of patients with aNTN. The risk of pain recurrence after microvascular decompression was 14% (n=3) in the first three years, and 34% (n=4) after 5 years. The use of video endoscopy made it possible to identify the blood vessels compressing the root of the trigeminal nerve with a minimal displacement of the cerebellum and cranial nerves when visualizing the neurovascular conflict.
 Conclusion: The microvascular decompression method with video endoscopy is effective in the treatment of patients with aNTN.

Sling technique in microvascular decompression surgery for trigeminal neuralgia: early experience and functional outcomes

BackgroundTrigeminal neuralgia (TGN) is a facial pain disorder often caused by arterial compression of the trigeminal nerve. Microvascular decompression (MVD) remains the most definitive treatment for this disorder, with a reported cure rate between 60 and 80%. MVD techniques often involve a retrosigmoid craniotomy with placement of an inert foreign material, such as Gore-Tex or Teflon, between the nerve and the compressing vessel.Recurrence of TGN after MVD has been associated with vessel migration and adhesion formation. In this study, we tested the use of Gore-Tex sling, fixed in place with fibrin glue to displace the compressing vessel away from the nerve.ResultsThis is a retrospective study including 20 patients who had an MVD for treatment of idiopathic TGN where a sling of Gore-Tex was used with the application of fibrin glue to prevent dislocation of the vessel. It showed that sling MVD technique is an effective method for treatment of classic trigeminal neuralgia. Eighteen patients improved within 2 weeks postoperatively. One patient had recurrence of symptoms and was reoperated 1 year later.ConclusionGore-Tex slinging technique is a safe simple technique for preventing re-dislocation of the offending vessel and thus recurrence of symptoms. However, larger series is needed to judge on the long-term efficacy and safety of this technique.

Alterations of degree centrality and functional connectivity in classic trigeminal neuralgia.

Recent neuroimaging studies have indicated a wide range of structural and regional functional alterations in patients with classic trigeminal neuralgia (CTN). However, few studies have focused on the intrinsic functional characteristics of network organization in the whole brain. Therefore, the present study aimed to characterize the potential intrinsic dysconnectivity pattern of the whole brain functional networks at the voxel level using the degree centrality (DC) analysis in CTN patients. Thirty-four patients with CTN and twenty-nine well-matched healthy controls (HCs) participated in this study. All subjects underwent resting-state functional magnetic resonance imaging (rs-MRI) examination and clinical and neuropsychologic assessments. DC is a graph theory-based measurement that represents the overall functional connectivity (FC) numbers between one voxel and other brain voxels. We first investigated brain regions exhibiting abnormal DC, and further identified their perturbation on FC with other brain regions using a seed-based FC analysis in patients with CTN. In addition, correlation analyses were performed to evaluate the relationship between the abnormal DC value and clinical variables in CTN patients. Compared with the HCs, the patients with CTN exhibited significantly greater DC values in the right pallidum and right putamen, and lower DC values in the right lingual gyrus, right calcarine sulcus, left paracentral lobule, and left midcingulate cortex. A further seed-based FC analysis revealed that the right lingual gyrus showed decreased FC within the visual network and with other core brain networks, including the sensorimotor network, default mode network, and salience network, relative to HCs. Additionally, the left midcingulate cortex exhibited decreased FC within the middle cingulate cortex and the visual network in CTN patients. Moreover, the DC value in the left midcingulate cortex was negatively correlated with the illness duration. The present study shows that CTN patients exhibited specific functional connectivity network alterations in the basal ganglia, visual network, and salience network, which may reflect the aberrant neural network communication in pain processing and modulation. These findings may provide novel insight for understanding the mechanisms of pain chronicity in CTN patients.

Objectively-captured Changes in Trigeminal Fibers before and after Microvascular Decompression Using 3D T2-SPACE MRI Might Relate to Eventual Residual Symptoms.

Although microvascular decompression (MVD) is a reliable treatment for trigeminal neuralgia (TN), neurosurgeons sometimes encounter patients whose symptoms do not improve postoperatively or who experience good treatment efficacy but develop other sensory disturbances. This study aims to objectively identify changes in nerve fibers before and after surgery by MRI and to clarify the relationship between the changes and residual postoperative symptoms. We retrospectively analyzed data from 36 consecutive patients who underwent MVD for classical TN at our hospital between November 2019 and November 2020. Cases that fulfilled the diagnostic criteria for multiple sclerosis were excluded. We confirmed the changes on the brainstem side of the trigeminal nerve preoperatively and at seven days postoperatively using 3D T2-SPACE MRI, in which the patients were divided into three groups: preoperative T2 high intensity positive (A), postoperative T2 high intensity positive (B), and no T2 high-intensity region (C). The primary outcome measures were therapeutic efficacy and frequency of postoperative numbness. The results of MVD surgery were evaluated one year postoperatively. The percentage of cases in which treatment outcomes were rated as excellent or good at one year: group A: 0 (0%), group B: 6 (100%), and group C: 25 (96.2%) (p < 0.05); the frequency of numbness: 2 (50%) in group A, 3 (50%) in group B, and 1 (3.8%) in group C, indicating significant differences between the three groups (p < 0.05). 3D T2-SPACE MRI sequences can be used to identify changes in trigeminal nerve fibers before and after MVD, which might correlate with eventual residual symptoms.

Classical trigeminal neuralgia recurrence after vascular decom - pression: analysis of the causes and features of the clinical picture

Introduction. Pain syndrome recurrence in patients with classical trigeminal neuralgia (CTN) after surgical treatment is an important and relevant issue, despite the advances in the diagnosis of the disease, progress in approaches to patient selection, and proven surgical tactics. The aim of the study is to evaluate the affecting factors for redo surgery in patients with CTN recurrence. Materials and methods. 257 patients with CTN recurrence operated on at the FSAI N.N. Burdenko National Medical Research Center for Neurosurgery of the Ministry of Health of the Russian Federation for the period from 2012 to 2017 were involved in the prospective nonrandomized study. Intraoperative findings and pain structure in postoperative period were evaluated in patients after revision surgery. Burchiel classification, DN4 Questionnarie, and Barrow Neurological Institute Pain Intensity Score (BNI-PS) were used. Results. CTN recurrence in the early and late post-operative periods was registered in 33 patients, which accounted for 13% of the total number of patients in the study group. 58% of them underwent secondary surgical intervention. The efficacy of redo surgery was noted in 79% of patients with complete regression of pain. Patients with CTN and neuropathy combination were admitted to alternative methods (neuromodulation, radiosurgery, radiofrequency ablation). In patients who received stimulation of the branches of the trigeminal nerve after vascular decompression, pain regression was observed in 100% of cases. Patient distribution after combined treatment was 78% for BNI-PS score I and 22% for BNI-PS score 2-3, respectively. Conclusion. In patients with “pure” CTN recurrence, redo surgery presents an effective method of treatment. In patients with CTN and neuropathy combination, repeat vascular decompression is effective only in terms of paroxysmal pain. Thus, multidisciplinary approach is needed – combining adjunctive methods of treatment in neurology, neurosurgery, pain management, and radiotherapy.

Altered Structural and Functional Abnormalities of Hippocampus in Classical Trigeminal Neuralgia: A Combination of DTI and fMRI Study.

Diffusion tensor imaging (DTI) and resting-state functional magnetic resonance imaging (rs-fMRI) were applied to speculate the altered structural and functional abnormalities within the hippocampus in classical trigeminal neuralgia (CTN) patients by detecting the alteration of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and regional homogeneity (ReHo). Patients and Methods. Multimodal MRI dataset (DTI and fMRI) and clinical indices (pain and neuropsychological scores) were collected in 27 CTN patients and 27 age- and gender-matched healthy controls (HC). Two independent-sample t-tests were performed to compare the ADC, FA, and ReHo values in hippocampus areas between CTN patients and HC. Correlation analyses were applied between all the DTI and fMRI parameters within the hippocampus and the VAS (visual analog scale), MoCA (Montreal cognitive assessment), and CDR (clinical dementia rating) scores. CTN patients showed a significantly increased FA values in the right hippocampus (t = 2.387, P = 0.021) and increased ReHo values in the right hippocampus head (voxel P < 0.001, cluster P < 0.05, FDR correction) compared with HC. A positively significant correlation was observed between the ReHo values and MOCA scores in the right hippocampus head; FA values were also positively correlated with MOCA scores in the right hippocampus. CTN patients demonstrated an abnormality of structures and functions in the hippocampus, which may help to provide novel insights into the neuropathologic change related to the pain-related dysfunction of CTN.

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

BackgroundTrigeminal 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.ObjectivesWe aimed to assess outcome and complications after microvascular decompression from our center.MethodsWe 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.ResultsOf 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.ConclusionMicrovascular 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 registrationClinical.trials.gov registration no. NCT04445766.

Microvascular decompression: Diversified of imaging uses, advantages of treating trigeminal neuralgia and improvement after the application of endoscopic technology.

Classical trigeminal neuralgia (CTN) is a unilateral and severe facial pain disease, which seriously affects the patient's quality of life. Microvascular decompression (MVD) is currently the most effective surgical method, and it is the only treatment for the etiology of CTN. Imaging for MVD has been increasingly used, and the advantages and disadvantages of endoscopy-assisted vascular decompression surgery have been controversially debated. In this review, we aimed to discuss the advantages of MVD in the treatment of patients with CTN, the importance of using imaging in disease management, and the improvements of vascular decompression surgery through the application and maturity of endoscopic techniques. Compared with other surgical methods, MVD has more prominent short- and long-term treatment effects. Its selection depends on the accurate discovery of neurovascular compression by preoperative imaging. Moreover, magnetic resonance imaging plays a diverse role in MVD, not only in identifying the responsible vessels but also in determining the prognosis and as a tool for scientific research. The use of endoscopic techniques provides improved visualization of the MVD and additional benefits for vascular decompression surgery.

Increase in Trigeminal Nerve Cross-Sectional Area on Immediate Postoperative MRI Predicts Favorable Outcome After Microvascular Decompression for Classical Trigeminal Neuralgia.

Although distortion or indentation of a trigeminal nerve due to neurovascular compression (NVC) is associated with classical trigeminal neuralgia, whether morphological change in the trigeminal nerve is relieved by eliminating NVC has not been studied. To estimate morphological change in the trigeminal nerve after microvascular decompression (MVD). Fifty patients with classical trigeminal neuralgia who underwent MVD were included. Using coronal images in both preoperative and postoperative MRI, the trigeminal nerve cross-sectional area (CSA) was measured at 4 mm anterior to the nerve entry into the pons. Clinical outcomes were assessed using the Barrow Neurological Institute Pain Intensity Scale (BNI-PS) at the patient's latest follow-up. Forty-one patients achieved favorable outcomes without medication (BNI-PS I or II), and 9 patients had residual pain (BNI-PS ≥ 3A). The mean symptomatic trigeminal nerve CSA was increased by 51.47% after MVD in the favorable outcome group (preoperative: 4.37 ± 1.64 mm 2 vs postoperative: 6.26 ± 1.76 mm 2 , P < .01), whereas it was not significantly changed in the unfavorable outcome group (preoperative: 4.20 ± 1.19 mm 2 vs postoperative: 4.43 ± 1.24 mm 2 , P = .69). Kaplan-Meier survival analysis showed that the 3-year probability of maintaining a favorable outcome was 92.3 ± 7.4% and 56.1 ± 11.9%, for those whose symptomatic trigeminal nerve CSA was increased by over 20% and less than 20%, respectively ( P < .01). Morphological changes in the trigeminal nerve due to NVC could be recovered by MVD, and increases in the trigeminal nerve CSA predicted favorable outcomes.

Rare case of trigeminal neuralgia due to vascular compression presenting with severe headache – A case report

Trigeminal neuralgia (TN) is a nerve disorder of the face. Tic douloureux is another name for it. It is regarded to be among the most severe human illnesses. A 55-year-old elderly female with a migraine background appeared with a severe headache and terrible intermittent ache on the left part of her face for the previous 3 weeks. Migraine medicines and over-the-counter analgesics did not ease the agony. A magnetic resonance imaging scan with contrast demonstrated direct contact between the superior cerebellar artery and the trigeminal nerve on the left face. Oral medicine is the primary way of management for TN due to its non-invasiveness, minimal price, and effectiveness rate. Surgical therapy for TN tries to release the strain of the problematic artery or vein pressing the trigeminal nerve, halting the uncontrolled pain impulses. A crucial requirement for TN diagnosis is pain that cannot be ascribed to any other scenario and the absence of any apparent CNS pathology. Patients will be relieved from discomfort and unneeded dental and medical therapy if they receive an early, accurate diagnosis, and formulate an ideal therapy plan based on their age and general health. This article aims to present a case of classical TN caused by vascular compression that presented with severe headache and was successfully treated with microvascular decompression surgery.

3D-visualization of neurovascular conflict in patients with classical trigeminal neuralgia

Introduction. MRI is well-recognized as a leading method of neurovascular conflict (NVC) evaluation in patients with classical trigeminal neuralgia (CTN). NVC is regarded as the cause of the development of deformity, atrophy, or dislocation of the trigeminal nerve root. Currently, the number of worldwide publications concerning the analysis of NVC 3D-reconstruction for the diagnosis of cranial nerve hyperfunction syndromes is still small. The aim of the study was to evaluate the efficacy of NVC 3D-visualization for CTN diagnosis compared to conventional examination protocols. Materials and methods. From 2018 to 2020, 30 patients with CTN who underwent 3D-visualization of the NVC as a preoperative examination were involved in prospective nonrandomized study. T-2 3D (FIESTA), 3D-TOF and T1 FRSGR were utilized for 3D rendering (Fusion protocol). The obtained data were compared only FIESTA-based «prediction» of NVC and with intraoperative findings. Results. FIESTA-only prediction was effective in 93 %, and Fusion protocol — in 97 % of arterial type of NVC cases. Fusion protocol showed its supremacy in detecting venous type of compression. Average efficacy of FIESTA-only prediction was 84 %, whereas Fusion protocol showed 97 % correlation with intraoperative findings. Conclusion. Fusion protocol allows fast detection of NVC, its type and localization (not only at the REZ of the fifth nerve but also at its cisternal portion). It makes possible tracing the course of the compressing vessel and assess the «convenience» of decompressing the TN root, taking into account the spatial relationship of the brainstem, vessels of the cerebellopontine angle and cranial nerves. Unlike FIESTA-only scanning, 3D-rendering also offers a possibility of preoperative simulation of microvascular decompression by recreating intraoperative view with precise details. Patient examination with FIESTA-only scanning is inferior to the «extended» algorithm for NVC diagnosis and does not have these capabilities.

Narrow ovale foramina may be involved in the development of primary trigeminal neuralgia.

BackgroundThe etiology of primary trigeminal neuralgia remains unclear and is worthy of further study; In this study, the morphometric characteristics of ovale foramina between various groups were compared and analyzed to explore the novel cause of primary trigeminal neuralgia.MethodsHigh-resolution three-dimensional reconstruction images from head computed tomography of 109 patients with primary trigeminal neuralgia affecting the third branch of the trigeminal nerve and 46 healthy controls were retrospectively reviewed. Among the 109 primary trigeminal neuralgia patients, 79 patients with apparent neurovascular compression (not simply contact) demonstrated on MRI or during surgery were divided into the classical trigeminal neuralgia group and 30 patients with MRI showing no significant abnormalities were divided into idiopathic trigeminal neuralgia group. The morphometric parameters including the area, width and length of ovale foramina were examined through the use of radiologic methods.ResultsIn this study, the average minimum area, width and length of 79 ovale foramina on the affected and unaffected sides in the classical trigeminal neuralgia group were 21.83 ± 8.45, 21.94 ± 7.93 mm2, 2.32 ± 0.91, 2.58 ± 0.81, 5.32 ± 1.29, and 5.26 ± 1.21 mm, respectively. No significant difference in these parameters was observed (p > 0.05). However, in the idiopathic trigeminal neuralgia group, the average minimum area, width and length of 30 ovale foramina were 21.33 ± 8.21, 22.85 ± 8.36 mm2, 2.25 ± 0.90, 2.79 ± 0.96, 5.20 ± 1.27, and 5.28 ± 1.19 mm, respectively. The width on the symptomatic side was significantly smaller (p = 0.03) than that on the asymptomatic side. No significant difference in area (p = 0.48) or length (p = 0.79) was observed. In addition, when compared with the healthy control group, the area and width of ovale foramina on the symptomatic side in both groups were significantly smaller. No significant difference in length was observed.ConclusionsBy comparing and analyzing the statistical data, it can be inferred that a narrow foramen ovale is associated with primary trigeminal neuralgia, as well as its recurrence after microvascular decompression.

Trigeminal Neuralgia - What Do We Know about the Causes, Diagnosis and Treatment?

Trigeminal Neuralgia - What Do We Know about the Causes, Diagnosis and Treatment? Abstract. Classical trigeminal neuralgia is typically characterized by a stimulus-evoked, recurrent and intense short-lasting stabbing pain in the innervation area of the trigeminal nerve. Its intensity is among the most severe pain imaginable in humans, and yet it is often misdiagnosed and undertreated. Triggers are common activities of daily life like talking or eating. The classical trigeminal neuralgia is due to a neurovascular compression at the nerve root entry zone. The secondary form is related to an underlying neurological disease (caused for example by multiple sclerosis or compression by a brain tumor); the etiology of the idiopathic trigeminal neuralgia is unknown. Treatment options include both medication (mostly antiepileptic drugs) and escalated interventional approaches (microvascular decompression, neurolesional percutaneous procedures, neuromodulative therapeutic options and radiosurgery).

Sagittal Angle of the Trigeminal Nerve at the Porus Trigeminus: A Novel Measurement to Distinguish Different Causes of Classic Trigeminal Neuralgia.

Classic trigeminal neuralgia is a clinical syndrome of facial pain, most often attributable to vascular compression of the proximal cisternal segment of the trigeminal nerve and treatable with microvascular decompression of the nerve. Some patients, however, meet all clinical criteria for classic trigeminal neuralgia yet do not respond to microvascular decompression. Because the reasons for surgical failure are not well understood, the aim of this study was to determine if a subset of patients with classic trigeminal neuralgia could be distinguished by measuring the angle of the trigeminal nerve in the sagittal plane as the nerve traverses the porus trigeminus. We retrospectively identified patients with either classic trigeminal neuralgia (n = 300) or hemifacial spasm (n = 300) who had undergone MR imaging, including 3-plane steady-state free precession imaging. Patients with hemifacial spasm served as controls. On sagittal steady-state free precession images, we measured the angle of each trigeminal nerve as it crosses through the porus trigeminus into the Meckel cave (SATNaPT). In patients with classic trigeminal neuralgia, we separated the nerves into symptomatic and asymptomatic sides. We compared these 3 groups using the Student t test. Control patients had a mean SATNaPT of 170° (SD, 11°) with a normal distribution. The contralateral asymptomatic nerve in patients with classic trigeminal neuralgia had the same distribution of angles. The symptomatic nerves in patients with classic trigeminal neuralgia had a bimodal distribution; 83% of patients fell into the same distribution as the asymptomatic nerves, but the other 15% had an average angle of 143° (SD, 7°). This difference was statistically significant (P < .0001). Patients with the clinical syndrome of classic trigeminal neuralgia fell into 2 categories based on the radiologic measurement of the SATNaPT. Most patients had an anatomically normal nerve that was affected by vascular compression, but 17% of these patients had aberrant anatomy that may cause or contribute to their clinical presentation. Further study is needed to determine whether this subset of patients should receive a different surgery to better address their underlying anatomic abnormality. The SATNaPT measurement should be included in every MR imaging interpretation performed on patients with classic trigeminal neuralgia.

Safety and efficacy of erenumab in patients with trigeminal neuralgia in Denmark: a double-blind, randomised, placebo-controlled, proof-of-concept study

Trigeminal neuralgia is a severe facial pain disorder that is difficult to treat. Erenumab, a monoclonal antibody against the calcitonin gene-related peptide (CGRP) receptor, has proven efficacy in migraine. Erenumab modulates sensory processing in peripheral trigeminal pain pathways in mice and was reported to be effective for patients with trigeminal neuralgia in open-label studies. We aimed to evaluate the efficacy of erenumab in patients with trigeminal neuralgia. We did a randomised, double-blind, placebo-controlled trial in adults (aged 18-85 years) with idiopathic or classic trigeminal neuralgia as defined by the 3rd edition of the International Classification of Headache Disorders. The trial was based at the Danish Headache Center, Copenhagen University Hospital. Eligible participants had no clinically significant cerebrovascular or cardiovascular disease, had self-reported pain intensity of at least 4 on the 11-point Numeric Rating Scale (0=no pain, 10=worst pain imaginable), and had at least three daily pain paroxysms. After a 1-week pre-screening period, patients entered a 4-week baseline period. Participants who met pain inclusion criteria at the end of the baseline period were randomly assigned (1:1) to receive subcutaneous injections of either erenumab 140 mg or placebo and entered the 4-week follow-up period. Randomisation was done in blocks of 10 using a computer-generated schedule by a third-party company. Participants and assessors were masked to treatment allocation, and erenumab and placebo were packed in identical prefilled syringes. The primary outcome was the number of responders, defined as patients who had a reduction of at least 30% in mean average daily pain intensity during the follow-up period compared with during the baseline period, analysed in the intention-to-treat population. This trial is registered with the European Union Drug Regulating Authorities Clinical Trials Database, EudraCT number 2019-000848-95. We assessed 860 patients for suitability and excluded 741 between Oct 28, 2019, and Sept 13, 2021. 119 participants entered a 1-week pre-screening period and 26 were excluded, 93 participants entered a 4-week baseline period with 13 excluded before randomisation, and 80 participants were randomly assigned to erenumab 140 mg (n=40) or placebo (n=40). There was no difference between groups in the number of responders at 4 weeks in the intention-to-treat population (14 [35%] of 40 with erenumab vs 18 [45%] of 40 with placebo; estimated effect size -10% [95% CI -31 to 11]; p=0·36). 20 (50%) of 40 participants reported adverse events in each group. The most common adverse events were constipation (28%) and headache (10%) in the erenumab group, and headache (13%), constipation (10%), and abdominal pain (10%) in the placebo group. Erenumab did not reduce pain intensity compared with placebo in patients with trigeminal neuralgia and CGRP probably does not have an important role in paroxysmal pain. Well tolerated, effective treatments in trigeminal neuralgia are still needed. Novartis.

Amplitude of low-frequency fluctuation after a single-trigger pain in patients with classical trigeminal neuralgia

ObjectiveThis study aimed to explore the central mechanism of classical trigeminal neuralgia (CTN) by analyzing the static amplitude of low-frequency fluctuation (sALFF) and dynamic amplitude of low-frequency fluctuation (dALFF) in patients with CTN before and after a single-trigger pain.MethodsThis study included 48 patients (37 women and 11 men, age 55.65 ± 11.41 years) with CTN. All participants underwent 3D-T1WI and three times resting-state functional magnetic resonance imaging. The images were taken before stimulating the trigger zone (baseline), within 5 s after stimulating the trigger zone (triggering-5 s), and in the 30th minute after stimulating the trigger zone (triggering-30 min). The differences between the three measurements were analyzed using a repeated-measures analysis of variance.ResultsThe sALFF values of the bilateral middle occipital gyrus and right cuneus gradually increased, and the values of the left posterior cingulum gyrus and bilateral superior frontal gyrus gradually decreased in triggering-5 s and triggering-30 min. The values of the right middle temporal gyrus and right thalamus decreased in triggering-5 s and subsequently increased in triggering-30 min. The sALFF values of the left superior temporal gyrus increased in triggering-5 s and then decreased in triggering-30 min. The dALFF values of the right fusiform gyrus, bilateral lingual gyrus, left middle temporal gyrus, and right cuneus gyrus gradually increased in both triggering-5 s and triggering-30 min.ConclusionsThe sALFF and dALFF values changed differently in multiple brain regions in triggering-5 s and triggering-30 min of CTN patients after a single trigger of pain, and dALFF is complementary to sALFF. The results might help explore the therapeutic targets for relieving pain and improving the quality of life of patients with CTN.

Botulinum Toxin as an Effective Treatment for Trigeminal Neuralgia in Surgical Practices

Background: Trigeminal neuralgia (TN) is a common cause of craniofacial pain with many medical and surgical therapies, all of which are imperfect. We examine the use of botulinum toxin type-A (BTX-A) as an intermediary approach in surgical practices. Methods: We retrospectively identified TN patients seen by both pain neurology and neurosurgery at our center. Demographics were collected. Pain intensity was assessed using the numerical rating scale (NRS) and compared from baseline to after BTX-A treatment via paired t test. Responder status was assessed, and success of BTX-A was determined for each cohort. Doses of common medications were compared between baseline visit and the most recent BTX-A administration visit. Results: Thirty-one patients underwent BTX-A therapy for TN, 24 (77%) female and 7 (23%) male. Mean age was 62.5 ± 3.1 years and 29 (94%) identified as white. When divided into cohorts according to indication, 11 (35%) failed prior TN surgery, 9 (29%) either declined surgery or were poor surgical candidates, 4 (13%) had multiple sclerosis, 4 (13%) had trigeminal neuropathic pain, and 3 (10%) had atypical TN with pain in additional dermatomes outside the trigeminal distribution. Significant reductions in NRS from baseline to following initial BTX-A treatment were seen in the declined/high risk for surgery (p = 0.004) and those who failed prior TN surgery (p = 0.035) groups. No significant variation in demographics was found between any two groups (p > 0.05 for all). Finally, there was no significant reduction in total daily dose of gabapentin, carbamazepine, oxcarbazepine, baclofen, or lamotrigine in BTX-A responders (p > 0.05 for all). Discussion: Indication is an important predictor for BTX-A, with classical TN patients exhibiting the highest response rates. This research highlights the viability of BTX-A as an important tool in the arsenal of providers seeking to treat TN in a minimally invasive manner.

The practical limits of high-quality magnetic resonance imaging for the diagnosis and classification of trigeminal neuralgia

BackgroundNeurovascular compression (NVC) has been the primary hypothesis for the underlying mechanism of classical trigeminal neuralgia (TN). However, a substantial body of literature has emerged highlighting notable exceptions to this hypothesis. The purpose of this study is to assess the reliability and diagnostic accuracy of high resolution, high contrast MRI-determined neurovascular contact for TN. MethodsWe performed a retrospective, randomized, and blinded parallel characterization of neurovascular interaction and diagnosis in a population of TN patients and controls using four expert reviewers. Performance statistics were calculated, as well as assessments for generalizability using shuffled bootstraps. ResultsFair to moderate agreement (ICC: 0.32–0.68) about diagnosis between reviewers was observed using MRIs from 47 TN patients and 47 controls. On average reviewers performed no better than chance when diagnosing participants, with an accuracy of 0.57 (95% CI 0.40, 0.59) per patient. ConclusionWhile MRI is useful in determining structural causes in secondary TN, expert reviewers do no better to only slightly better than chance with distinguishing TN with MRI, despite moderate agreement. Further, the causal role of NVC for TN is not clear, limiting the applicability of MRI to diagnose or prognosticate treatment of TN.

A single centre case series of microvascular decompression surgery for classical trigeminal neuralgia: functional outcomes and report of a unique conflict

BackgroundMicrovascular decompression surgery for trigeminal neuralgia is now considered the benchmark surgical procedure for intractable trigeminal neuralgia of any variety. The objective of this study is to share our experience in managing classical trigeminal neuralgia with microvascular decompression surgery looking into both immediate and late functional outcomes at 3 and 6 months post op. We also report a unique case of trigeminal neuralgia due to a tributary of the petrosal vein passing through the substance of the trigeminal nerve itself at its root entry zone.ResultsThis study included 20 patients; it showed that microvascular decompression surgery of the trigeminal nerve is an effective method for treatment of classic trigeminal neuralgia (p value < 0.001). The trigeminal root was compressed by the superior cerebellar artery in 75% of patients. A vein contributed to the compression in 45% of patients and was the only compressing vessel in 15%.ConclusionMicrovascular decompression surgery is the treatment of choice in patients with medically refractory trigeminal neuralgia, unless their general condition prohibits it. It’s also worth noting that the normal anatomy of the veins in this region is quite variable and the venous structures causing a neurovascular contact are more or less inconsistent. To the best of our knowledge and despite the wide range and progress in microvascular decompression surgery for trigeminal neuralgia, this is the first reported case in the literature for a neurovascular conflict caused by a vein passing through the trigeminal nerve itself.

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia: Technical Note Describing a Single-Center Experience

Microscopic microvascular decompression (MVD) of the trigeminal nerve is the gold standard surgical treatment for medically refractory classical trigeminal neuralgia. Endoscopy has significantly advanced surgery and provides enhanced visualization of the cerebellopontine angle and its critical neurovascular structures.We present our initial experience of fully endoscopic microvascular decompression (e-MVD). This retrospective case series investigated e-MVD performed from September 2016 to February 2020 at a single institution. Clinical data including presenting symptoms, medications, operative findings, postoperative complications, and outcomes were recorded. The 5-point Barrow Neurological Institute (BNI) pain intensity score was used to quantify patients' pain relief. During the study period, 25 patients with trigeminal neuralgia (10 males, 15 females; mean [SD] age= 63 [10.4] years) underwent e-MVD. All patients had a preoperative BNI score of V. The left side was affected in 15 patients. Complications occurred in 2 patients: both experienced hearing loss, and one experienced transient facial weakness 7 days after surgery. The facial weakness had resolved by the last follow-up. All patients were completely pain-free (BNI score I) immediately postoperatively. On latest follow-up, 22 patients have remained pain-free, and 3 patients have recurrent pain that is being controlled with medication (BNI score III). Our study demonstrated that e-MVD is a safe, possibly effective method of performing MVD with the added benefit of improved visualization of the operative field for the operating surgeon and the surgical team. Larger prospective studies are required to evaluate whether performing e-MVD confers any additional benefits in long-term clinical outcome of patients with trigeminal neuralgia.