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Chronic neuropathic pain can result from nervous system injury and can persist in the absence of external stimuli. Although ongoing pain characterizes the disorder, in many individuals, the intensity of this ongoing pain fluctuates dramatically. Previously, it was identified that functional magnetic resonance imaging signal covariations between the midbrain periaqueductal gray (PAG) matter, rostral ventromedial medulla (RVM), and spinal trigeminal nucleus are associated with moment-to-moment fluctuations in pain intensity in individuals with painful trigeminal neuropathy (PTN). Since this brainstem circuit is modulated by higher brain input, we sought to determine which cortical sites might be influencing this brainstem network during spontaneous fluctuations in pain intensity. Over 12 min, we recorded the ongoing pain intensity in 24 PTN participants and classified them as fluctuating (n = 13) or stable (n = 11). Using a PAG seed, we identified connections between the PAG and emotional-affective sites such as the hippocampal and posterior cingulate cortices, the sensory-discriminative posterior insula, and cognitive-affective sites such as the dorsolateral prefrontal (dlPFC) and subgenual anterior cingulate cortices that were altered dependent on spontaneous high and low pain intensity. Additionally, sliding-window functional connectivity analysis revealed that the dlPFC-PAG connection anticorrelated with perceived pain intensity over the entire 12 min period. These findings reveal cortical systems underlying moment-to-moment changes in perceived pain in PTN, which likely cause dysregulation in the brainstem circuits previously identified, and consequently alter the appraisal of pain across time.

Background: The gut microbiota may be involved in neuropathic pain. However, the causal association between gut microbiota and neuropathic pain remains unclear. Whether immune cells and inflammatory factors mediate the pathway from gut microbiota to neuropathic pain has not been elucidated. Methods: We obtained the summary data of 412 gut microbiota, 731 immune cells, 91 inflammatory factors, and five types of neuropathic pain (drug-induced neuropathy, postherpetic neuralgia, sciatica, trigeminal neuralgia, and unspecified neuralgia) from large-scale genome-wide association study (GWAS) datasets and the FinnGen database. We used bidirectional Mendelian randomization (MR) analysis to explore the causal association between gut microbiota and neuropathic pain. Additionally, we conducted a mediation analysis to identify whether immune cells and inflammatory factors act as mediators within these causal relationships. Results: Our study revealed 30 causal relationships between 26 gut bacterial taxa and five types of neuropathic pain, including four associated with drug-induced neuropathy, six with postherpetic neuralgia, five with sciatica, eight with trigeminal neuralgia, and seven with unspecified neuralgia. Moreover, we identified 35 gut bacterial pathway abundances causally involved in neuropathic pain. The reverse MR analysis showed no evidence of reverse causality from gut microbiota to neuropathic pain. Mediation analysis demonstrated that the immune cell phenotype "HLA-DR++ monocyte % leukocyte" mediated the causal relationship between p_Proteobacteria and sciatica with a mediation proportion of 36.15% (P = 0.038), whereas "CD11c on CD62L+ myeloid dendritic cell" mediated the causal pathway from assimilatory sulfate reduction to trigeminal neuralgia with a mediation proportion of 27.90% (P = 0.041). Conclusion: This study identified the causal relationships between several specific gut microbiota and various neuropathic pain subtypes. Additionally, two immune cells may act as potential mediators in the pathways from gut microbiota to neuropathic pain. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of primary trigeminal neuralgia (PTN) in radiology lacks the gold standard and largely depends on the identification of neurovascular compression (NVC) using magnetic resonance imaging (MRI) water imaging sequences. However, relying on this imaging sign alone often fails to accurately distinguish the symptomatic side of the nerve from asymptomatic nerves, and may even lead to incorrect diagnoses. Therefore, it is essential to develop a more effective diagnostic tool to aid radiologists in the diagnosis of TN. Purpose: This study aims to establish a radiomics-based machine learning model integrating multi-region of interest (multiple-ROI) MRI and anatomical data, to improve the accuracy in differentiating symptomatic from asymptomatic nerves in PTN. Methods: A retrospective analysis of MRI data and clinical anatomical data was conducted on 140 patients with clinically confirmed PTN. Symptomatic nerves of TN patients were defined as the positive group, while asymptomatic nerves served as the negative group. The ipsilateral Meckel's cavity (MC) was included in both groups. Through dimensionality reduction analysis, four radiomics features were selected from the MC and 24 radiomics features were selected from the trigeminal cisternal segment. Thirteen anatomical features relevant to TN were identified from the literature, and analyzed using univariate logistic regression and multivariate logistic regression. Four features were confirmed as independent risk factors for TN. Logistic regression (LR) models were constructed for radiomics model and clinical anatomy, and a combined model was developed by integrating the radiomics score (Rad-Score) with the clinical anatomy model. The models' performance was evaluated using receiver operating characteristic curve (ROC) curves, calibration curves, and decision curve analysis (DCA). Results: The four independent clinical anatomical factors identified were: degree of neurovascular compression, site of neurovascular compression site, thickness of the trigeminal nerve root, and trigeminal pons angle (TPA). The final combined model, incorporating radiomics and clinical anatomy, achieved an area under the curve (AUC) of 0.91/0.90 (95% CI: 0.87–0.95/0.81–0.96) and an accuracy of approximately 82% in recognizing symptomatic and normal nerves. Conclusion: The combined radiomics and anatomical model provides superior recognition efficiency for the symptomatic nerves in PTN, offering valuable support for radiologists in diagnosing TN. [ABSTRACT FROM AUTHOR]

Objective: Trigeminal schwannoma (TS), though a rare and benign tumor, becomes a significant surgical challenge due to its intricate location. This study aims to detail the long-term functional outcomes and tumor control post-surgical resection. Method: We analyzed a multicentric retrospective cohort of 39 patients operated on for a TS in five tertiary centers between January 1993 and July 2022. Results: Six TS (15%) were in the middle fossa (type M), two (5%) in the posterior fossa (type P), and two (5%) were extracranial (type E). Twenty-nine (75%) were Dumbbell shape: Eighteen (47%) were MP type, seven (18%) were MPE type, and four (10%) were ME type. Fifth nerve symptoms were the foremost preoperative complaint: hypesthesia (51%), trigeminal neuralgia (36%), and paresthesia (30%). We report a favorable evolution course for 61% of preexisting deficits (half of patients with preoperative paresthesia and neuralgia improved while only 5% of preoperative hypesthesia improved). Postoperative hypesthesia was the most frequent de novo deficit 14 (74%) and resolved in solely half the cases. Various approaches were used according to tumor type. Gross total resection (GTR), Subtotal resection (STR), and partial resection (PR) were achieved in respectively 33% (N = 13), 10% (N = 4), and 56% (N = 22) of patients. The mean clinical and radiological FU was 63 months (12 – 283 months). GTR led to no sign of recurrence (mean FU: 60 months – range: 12—283 months). For STR or PR (67%): 23 (88%) were assigned to a Wait-&-rescan policy (WS group) which offered stability in 70% (N = 16). Three cases (8%) underwent a complementary GKS (GammaKnife) on the residual lesion (GK group) without tumor change. Conclusion: For large TS, the completeness of resection must consider the potential functional burden of surgery. With giant infiltrating lesions, a strategy of planned subtotal resection, complemented by radiosurgery, either complementary or uppon regrowth, may provide similar oncological outcomes. [ABSTRACT FROM AUTHOR]

Background and purpose: Trigeminal neuralgia (TN) is a severe chronic pain condition, typically affecting patients over 50-year-old, caused by the compression of the nerve at the root entry zone (REZ) by blood vessels. While the diagnosis is clinical, advanced imaging like diffusion tensor imaging (DTI) is crucial to identify underlying causes and assessing nerve damage. DTI may help develop neuroimaging markers to improve understanding of TN and predict surgical outcomes. The goal of the present systematic review is to evaluate the effectiveness of DTI and tractography in order to better assess treatment planning and outcome prediction through the analysis of trigeminal nerve alterations. Methods: The authors conducted a systematic review and meta-analysis of the literature to compare radiological parameters identified in pre- and post-operative MRI with DTI sequences, including fractional anisotropy (FA), quantity of anisotropy (QA), radial diffusivity (RD), and to correlate these findings with post-operative clinical outcomes. A comprehensive search of the PubMed and Scopus databases was carried out for studies published between April 2010 and January 2024. Results: This review included 11 studies and 603 patients. Of the 363 patients with trigeminal neuralgia (TN), 193 underwent microvascular decompression (MVD), with 72.5% showing clinical improvement and 27.5% not improving, possibly due to chronic nerve damage. Four studies assessed radiological parameters before and after MVD, while two focused only on post-MVD data. The mean fractional anisotropy (FA) in affected nerves increased from 0.328 before MVD to 0.382 afterward. Five studies did not report postoperative outcomes, just comparing radiological parameters in TN patients versus healthy controls. Conclusions: Recent studies show that MRI-DTI parameters, including FA, RD, and QA, are useful for diagnosing trigeminal neuralgia and predicting treatment outcomes. Lower FA and higher RD values indicate better results after surgery. More research is mandatory to guide treatment decisions and enhance patients' care. [ABSTRACT FROM AUTHOR]

Classical trigeminal neuralgia (TN) is a chronic pain disorder characterized by severe, unilateral facial pain, often resulting from vasculonervous conflict. A less common cause of TN is vertebrobasilar dolichoectasia (VBD). Microvascular decompression (MVD) is the preferred surgical intervention for TN, but in case of VBD, the surgical procedure is more complex due to the aberrant vascular anatomy. This study aims to review the evidence on MVD for VBD-induced TN, and analyze operative challenges, efficacy, and postoperative outcomes. An illustrative case is also presented. We report on the case of a 62-year-old male with a 7-year history of right-sided TN affecting the maxillary (V2) and mandibular (V3) territories. The patient underwent MVD using the interposition technique, where Teflon sponges were placed between the basilar artery and the nerve. Postoperatively, the patient experienced complete pain relief without neurological deficits. At 12 months follow-up, the patient remained pain-free and off medications. We performed an extensive literature review using PubMed, Scopus, and Web of Sciences, highlighting the most relevant studies and findings on the topic. The literature review showed that, while MVD is effective in providing long-term pain relief in VBD-induced TN, the choice between interposition and transposition techniques remains debated. Interposition is easier to perform but may inadvertently increase nerve compression in some cases, whereas transposition offers more definitive decompression but carries higher technical risks. Our case and the available literature highlight the importance of individualized treatment planning in achieving optimal outcomes for patients with VBD-induced TN. Further research is needed to refine surgical techniques and minimize complications in this subset of TN patients. [ABSTRACT FROM AUTHOR]

Objective: To explore the efficacy and safety of 5% lidocaine‐medicated plaster (LMP) in patients with trigeminal neuralgia (TN). Background: TN is an excruciatingly painful type of neuropathic facial pain. Anti‐epileptics are the first‐line treatment for TN; however, these oral drugs alone sometimes fail to achieve satisfactory analgesic effects. Two retrospective studies have shown that LMP can be an effective and safe treatment option for some patients with TN. No other high‐quality clinical studies have explored the effect and safety of LMP in patients with TN. Methods: The PATCH trial is an enriched enrollment with randomized withdrawal, double‐blind, vehicle‐controlled, parallel‐group trial performed at five study centers. Eligible patients with TN received LMP during a 3‐week initial open‐label phase. Patients who met the response criteria entered the double‐blind treatment phase and were randomly assigned for treatment with either LMP (LMP group) or vehicle patches (control group) at a 1:1 ratio. Patients who met the criteria for treatment failure were withdrawn from the double‐blind treatment phase, and treatment was continued in the remaining patients for up to 28 days. The primary outcome was the number of treatment failures. The secondary endpoints were the time to loss of therapeutic response (LTR) in the double‐blind phase and the weekly mean pain severity in both the open‐label phase and the double‐blind phase of the study. Results: The first patient was enrolled in this study on May 1, 2021, and the enrollment of the last patient was completed on August 26, 2022. A total of 307 patients were initially screened, 226 (74.0%) of whom entered the open‐label phase. Of the 226 respondents, 124 (55.0%) were randomized to the double‐blind phase. In the double‐blind phase, 62 patients were assigned to the LMP group, and 62 were assigned to the control group. For the primary endpoint, 16 (26.0%) patients with LMP and 36 (58.0%) patients with vehicle patches met the treatment failure criteria during the double‐blind phase (relative risk, 0.48; 95% confidence interval [CI], 0.31 to 0.75; p < 0.001). The survival curve of the LTR showed that the LTR of LMP was significantly longer than that of the vehicle patches (hazard ratio, 0.275; 95% CI, 0.15 to 0.50; log‐rank p < 0.001). LMP also significantly reduced the weekly mean pain severity in the double‐blind phase of the study (p = 0.007). Conclusions: LMP produced partial relief of pain symptoms in some patients with TN. For responders, LMP may be used as an add‐on therapy in a multidrug treatment protocol. Plain Language Summary: The PATCH trial is an enriched enrollment, randomized withdrawal, double‐blind, vehicle‐controlled, parallel‐group study. The results of the PATCH trial supported that 5% lidocaine‐medicated plaster (LMP) produces partial relief of pain symptoms in some patients with trigeminal neuralgia. For responders, 5% LMP may be used as an add‐on therapy in a multidrug treatment protocol. [ABSTRACT FROM AUTHOR]

Purpose: Percutaneous lesioning-techniques for treating refractory Trigeminal Neuralgias not amenable to Micro-Vascular Decompression remain useful in neurosurgical practice. Success, avoidance of complications and reduction of side-effects depend on the accurate location of the lesion-maker especially for Radio-Frequency-Thermo-Rhizotomy (RF-Th-Rh). Added to X-ray-guidance, Intra-Operative Neurophysiology can be of significant help to achieve optimal accuracy of the surgery. Based on previous research, this article aims to describe the simplest way to use direct electrical stimulation of the trigeminal root to evoke clinically observable muscle responses allowing to precisely position the tip of the needle for accurate lesioning. Technique to evoke specific localizing muscle responses: Masticatory twitches can be easily produced by stimulating the motor root, through orthodromic conduction to the masticatory muscles. Evoked Muscle Responses (EMRs) can be elicited in the facial nerve territory by stimulating the sensory rootlets, through Trigemino-Facial Reflexes' pathways (TFRs). Responses in the Orbicularis Oculi is the well-known and readily used "Blink reflex". On the contrary, TFRs in the lower territory of the facial nerve escaped clinical investigations not having been explored under direct stimulation of the trigeminal root. For both, stimulation at 5 c/s produces better observable twitches (because saccadic) than at 50 c/s which elicits tetanic contractions. Conclusion: The localizing-value of these facial EMRs (associated to evocation of paresthesias) and of the masticatory responses, justifies mapping the trigeminal root before lesioning. Their use could be extended to the other lesioning-techniques: not only Glycerol Neurolysis but also to Balloon Compression (to ascertain location of the trocar at the contact of the TGN inside the Meckel cave) and Open partial Rhizotomies (before deciding to cut the rootlets corresponding to the trigger-zone). This is of importance since lesioning-techniques are needed because not all trigeminal neuralgias are responsive to or even indications of Micro-Vascular Decompression. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to develop a clinical-radiomics nomogram to predict the long-term outcomes of patients with classical trigeminal neuralgia (CTN) following microvascular decompression (MVD). Materials and methods: This retrospective study included 455 patients with CTN who underwent MVD from three independent institutions A total of 2030 radiomics features from the cistern segment of the trigeminal nerve were extracted computationally from the three-dimensional steady-state free precession and three-dimensional time-of-flight magnetic resonance angiography sequences. Using the least absolute shrinkage and selection operator regression, 16 features were chosen to develop radiomics signatures. A clinical-radiomics nomogram was subsequently developed in the development cohort of 279 patients via multivariate Cox regression. The predictive performance and clinical application of the nomogram were assessed in an external cohort consisting of 176 patients. Results: Sixteen highly outcome-related radiomics features extracted from multisequence images were used to construct the radiomics model, with concordance indices (C-index) of 0.804 and 0.796 in the development and test cohorts, respectively. Additionally, a clinical-radiomics nomogram was developed by incorporating both radiomics features and clinical characteristics (i.e., pain type and degree of neurovascular compression) and yielded higher C-indices of 0.865 and 0.834 in the development and test cohorts, respectively. K‒M survival analysis indicated that the nomogram successfully stratified patients with CTN into high-risk and low-risk groups for poor outcomes (hazard ratio: 37.18, p < 0.001). Conclusion: Our study findings indicated that the clinical-radiomics nomogram exhibited promising performance in accurately predicting long-term pain outcomes following MVD. Clinical relevance statement: This model had the potential to aid clinicians in making well-informed decisions regarding the treatment of patients with CTN. Key Points: Trigeminal neuralgia recurs in about one-third of patients after undergoing MVD. The clinical-radiomics nomogram stratified patients into high- and low-risk groups for poor surgical outcomes. Using this nomogram could better inform patients of recurrence risk and allow for discussion of alternative treatments. [ABSTRACT FROM AUTHOR]

Background A neurovascular conflict (NVC) is considered the cause of trigeminal neuralgia (TN) in 75% of cases, and if so, a microvascular decompression (MVD) can lead to significant pain relief. A reliable preoperative detection of NVC is essential for clinical decision-making and surgical planning, making detailed neuroradiologic imaging an important component. We present our experiences and clinical outcomes with preoperative planning of the MVD procedure in a virtual reality (VR) environment, based on magnetic resonance imaging (MRI) including magnetic resonance angiography (MRA) and magnetic resonance venography (MRV) sequences. Methods We analyzed the data of 30 consecutive MVDs in patients treated for TN, in a retrospective single-surgeon (R.A. Kockro) study. Out of the 30 cases, 26 were included. Preoperatively, MRA/MRV and MRI series were fused and three dimensionally reconstructed in a VR environment. All critical structures such as the trigeminal nerve as well as the arteries and veins of the cerebellopontine angle, the brainstem, the neighboring cranial nerves, and the transverse and sigmoid sinus were segmented. The NVC was visualized and a simulation of a retrosigmoid approach, with varying trajectories, to the NVC was performed. The intraoperative findings were then compared with the data of the simulation. The clinical outcome was assessed by a detailed review of medical reports, and follow-up-interviews were conducted in all available patients (20/26). Results The VR planning was well integrated into the clinical workflow, and imaging processing time was 30 to 40 minutes. There was a sole arterial conflict in 13 patients, a venous conflict in 4 patients, and a combined arteriovenous conflict in 9 patients. The preoperative simulations provided a precise visualization of the anatomical relationships of the offending vessels and the trigeminal nerves as well as the surrounding structures. For each case, the approach along the most suitable surgical corridor was simulated and the exact steps of the decompression were planned. The NVC and the anatomy of the cerebellopontine angle as seen intraoperatively matched with the preoperative simulations in all cases and the MVC could be performed as planned. At follow-up, 92.3% (24/26) of patients were pain free and all the patients who completed the questionnaire would undergo the surgery again (20/20). The surgical complication rate was zero. Conclusion Current imaging technology allows detailed preoperative visualization of the pathoanatomical spatial relationships in cases of TN. 3D interactive VR technology allows establishing a clear dissection and decompression strategy, resulting in safe vascular microsurgery and excellent clinical results. [ABSTRACT FROM AUTHOR]

Background: In addition to its critical role in neurogenesis, brain-derived neurotrophic factor (BDNF) modulates pain and depressive behaviors. Methods: In a translational perspective, we tested the anti-migraine activity of highly purified and characterized recombinant human BDNF (rhBDNF) in an animal model of cephalic pain based on the chronic and intermittent NTG administration (five total injections over nine days), used to mimic recurrence of attacks over a given period. To achieve this, we assessed the effects of two doses of rhBDNF (40 and 80 µg/kg) administered intranasally to adult male Sprague–Dawley rats, on trigeminal hyperalgesia (by orofacial formalin test), gene expression (by rt-PCR) of neuropeptides and inflammatory cytokines in specific areas of the brain related to migraine pain. Serum levels of CGRP, PACAP, and VIP (by ELISA) were also evaluated. The effects of rhBDNF were compared with those of sumatriptan (5 mg/kg i.p), administered 1 h before the last NTG administration. Results: Both doses of rhBDNF significantly reduced NTG-induced nocifensive behavior in Phase II of the orofacial formalin test. The anti-hyperalgesic effect of intranasal high-dose rhBDNF administration in the NTG-treated animals was associated with a significant modulation of mRNA levels of neuropeptides (CGRP, PACAP, VIP) and cytokines (IL-1beta, IL-10) in the trigeminal ganglion, medulla-pons, and hypothalamic area. Of note, the effects of rhBNDF treatment were comparable to those induced by the administration of sumatriptan. rhBDNF administration at both doses significantly reduced serum levels of PACAP, while the higher dose also significantly reduced serum levels of VIP. Conclusions: The findings suggest that intranasal rhBDNF has the potential to be a safe, non-invasive and effective therapeutic approach for the treatment of primary headache, particularly migraine. [ABSTRACT FROM AUTHOR]

Objective: This study aims to compare the efficacy and long-term prognosis of microvascular decompression (MVD) versus percutaneous balloon compression (PBC) in patients with idiopathic V2 (maxillary branch) trigeminal neuralgia. Methods: We retrospectively analyzed the clinical information and follow-up data of patients who underwent surgical treatment for V2 idiopathic trigeminal neuralgia from January 2020 to January 2023. A total of 58 patients were included in the MVD group and 99 in the PBC group. All surgeries were performed by two physicians at the same center, with follow-up conducted by a separate, trained researcher. We compared the initial versus 12-month postoperative pain relief rates (scored using the BNI), surgical complications, and described pain relief rates after long-term follow-up in both groups using Kaplan-Meier analysis. Results: The study included a total of 157 patients (MVD 58, PBC 99). The median age of patients in the MVD group was lower than that in the PBC group (58 [51-65] vs. 63 [58-69], p = 0.002). There was no significant difference between the two groups in terms of pain relief rates initially after surgery and at 12 months (p = 0.521, p = 0.713). However, the MVD group had significantly better outcomes regarding postoperative facial numbness (p < 0.0001), masticatory weakness (p = 0.0017), and other complications (p = 0.04). Kaplan-Meier analysis showed that MVD provided a longer duration of pain relief than PBC (p = 0.0323), with most recurrences in both groups occurring within 1-2 years after surgery. Conclusion: There were no significant differences in significant pain relief rates between the two groups initially after surgery and at 12 months. However, the MVD group showed a clear advantage over PBC regarding postoperative facial numbness, masticatory weakness, and other complications; moreover, Kaplan-Meier analysis revealed that MVD offers a longer duration of pain relief for patients. [ABSTRACT FROM AUTHOR]

Background and objectives: Trigeminal Neuralgia (TN) is a debilitating facial pain disorder, often necessitating surgical interventions when medication proves insufficient. Stereotactic Radiosurgery (SRS) is an established therapeutic option. Limited studies explored the feasibility of a third SRS procedure. Our study investigates the safety and efficacy of a third SRS procedure for recurrent TN. Methods: We performed a retrospective analysis across multiple centers using databases collected prospectively. Pain status was evaluated utilizing the BNI Pain Intensity Scales. The Kaplan–Meier method was employed to estimate the time to recurrence, with group comparisons conducted using log-rank tests. Associations were explored using Chi-square and logistic regression models. Results: Ten institutions contributed with a total of 35 patients. A third SRS revealed sustained effectiveness with a pain control rate of 82.7%. The median time to recurrence was 35.5 months. New sensory dysfunction following the third procedure occurred in 22% of patients who had preserved sensory function after the second procedure. When considering those who developed sensory dysfunction after the second procedure, 40% of the entire cohort was affected. There were no significant differences in pain recurrence intervals among the three procedures. A meta-analysis, combining data from previous studies, showed that 89.6% of patients achieved some degree of pain control after a third SRS, with 27.4% experiencing new sensory dysfunction and a median time to recurrence of 31.6 months. Conclusion: Our study, the largest on the topic, affirms the sustained effectiveness of a third SRS for TN, providing comparable pain relief to initial procedures. Notably, an extended pain-free interval after the third SRS session was observed. Facial sensory dysfunction emerged as the primary side effect. Larger studies are warranted to explore correlations with demographics and treatment parameters for a comprehensive understanding of repeat SRS in managing recurrent TN. [ABSTRACT FROM AUTHOR]

Background: Glossopharyngeal neuralgia (GN) is a rare pain syndrome often underdiagnosed. This study aimed to assess the challenges in diagnosing GN and identify patients at risk of misdiagnosis. Methods: Between 2010 and 2019, nine patients underwent microvascular decompression (MVD) of the glossopharyngeal nerve at two tertiary care hospitals. A retrospective analysis examined symptom characteristics, time to correct diagnosis, operative technique, and clinical outcomes. Barrow Neurological Institute (BNI) pain scores were assessed before surgery and on follow-up. Results: Six women and three men, aged 55 ± 14.3 years, with unilateral GN were included. Pain was predominantly in the ear (otalgic type) in four patients (44.4%), the pharynx or base of the tongue (pharyngeal type) in four (44.4%), and mixed in one (11.1%). Five patients reported pain radiating to the mandible, all initially misdiagnosed with trigeminal neuralgia (TN) and treated for 2.4(± 3.1) years before presenting to our institution. One case resulted in MVD of the trigeminal nerve and subsequent thermocoagulation of the Gasserian ganglion due to persistent pain. The correct diagnosis of GN was established later in patients with otalgic or mixed pain (3.8 ± 3.4 years) compared to those with pharyngeal pain (0.5 ± 1.0 years), showing a trend (U = 17.0, p = 0.07). There was a significant association between pain radiation to the mandible and misdiagnosis (x2 = 9.00, p = 0.003). Endoscopically assisted MVD via the median suboccipital subtonsillary approach was performed, resolving neurovascular conflicts with the PICA (9/9) and vertebral artery (3/9). Follow-up after 15.7(± 18.2) months showed significant pain reduction according to the BNI (preoperative BNI = 5.0 ± 0.0, postoperative BNI = 1.7 ± 1.0,t (8) = 10,CI [1.6–5.1], p < 0.001). No permanent surgery-related deficits occurred. Conclusion: Patients with GN, especially those with predominant otalgic pain and pain radiating to the mandible, are at higher risk of misdiagnosis due to similarities with TN. Despite the rarity of GN, increased awareness of its various pain manifestations may lead to earlier correct diagnoses, which is crucial for surgical treatment. [ABSTRACT FROM AUTHOR]

The trigeminal sensory system consists of the trigeminal nerve, the trigeminal ganglion, and the trigeminal sensory nuclei (the mesencephalic nucleus, the principal nucleus, the spinal trigeminal nucleus, and several smaller nuclei). Various sensory signals carried by the trigeminal nerve from the orofacial area travel into the trigeminal sensory system, where they are processed into integrated sensory information that is relayed to higher sensory brain areas. Thus, knowledge of the trigeminal sensory system is essential for comprehending orofacial pain. This review elucidates the individual nuclei that comprise the trigeminal sensory system and their synaptic transmission. Additionally, it discusses four types of orofacial pain and their relationship to the system. Consequently, this review aims to enhance the understanding of the mechanisms underlying orofacial pain. [ABSTRACT FROM AUTHOR]

Background: Neurovascular compression (NVC) is a primary etiology of trigeminal neuralgia (TN) and hemifacial spasm (HFS). Despite Magnetic Resonance Tomographic Angiography (MRTA) being a useful tool for 3D multimodal fusion imaging (MFI) in microvascular decompression (MVD) surgery planning, it may not visualize smaller arterial vessels and veins effectively. We validate a novel computed tomography angiography and venography (CTA/V) - diffusion tensor tractography (DTT) -3D-MFI to enhance the MVD surgical guidance. Methods: In this prospective study, 80 patients with unilateral primary TN or HFS who underwent MVD surgery were included. Imaging was conducted using CTA/V-DTT-3D-MFI compared with CT-MRTA-3D-MFI in predicting the responsible vessel and assessing the severity of NVC. Surgical outcomes were subsequently analyzed. Neurosurgery residents were provided with questionnaires to evaluate and compare the two approaches. Results: CTA/V-DTT-3D-MFI significantly improved accuracy in identifying the responsible vessel (kappa = 0.954) and NVC (kappa = 0.969) compared to CT-MRTA-3D-MFI, aligning well with surgical findings. CTA/V-DTT-3D-MFI also exhibited higher sensitivity in identifying responsible vessels (98.0%) and NVC (98.7%) than CT-MRTA-3D-MFI. Additionally, CTA/V-DTT-3D-MFI showed fewer complications, shorter operation times, and lower recurrence after one year (all p < 0.05). Resident neurosurgeons emphasized that CTA/V-DTT-3D-MFI greatly assisted in formulating precise surgical strategies for more accurate identification and protection of responsible vessels and nerves (all p < 0.001). Conclusion: CTA/V-DTT-3D-MFI enhances MVD surgery guidance, improving accuracy in identifying responsible vessels and NVC for better outcomes. This advanced imaging plays a crucial role in safer and more effective MVD surgery, as well as in training neurosurgeons. [ABSTRACT FROM AUTHOR]

Background: Evidence of an association between trigeminal neuralgia (TN) and subsequent cancer risk remains sparse. The present study aimed to examine the association between TN and cancer risk in the Danish population. Methods: A nationwide population-based cohort study using hospital diagnoses collected routinely and prospectively from Danish population-based registries in 1994–2022. Results: We identified 7846 individuals with a first-time diagnosis of TN. Within one year of diagnosis, we observed 193 cancer cases (standardized incidence rate (SIR) = 2.45, 95% confidence interval (CI) = 2.11–2.82). Absolute risk (AR) for all cancers within one year of TN diagnosis was 2.5% (95% CI = 2.2–2.9). Cancers of the head, neck and nervous system were most strongly associated with TN (AR 0.9% (95% CI = 0.7–1.1); SIR = 13.5 (95% CI = 10.5–17.0)) and the risk was persistently elevated one year after TN diagnosis. We observed 827 cancer diagnoses beyond one year after TN diagnosis, where smoking related cancers were associated with elevated cancer risk (SIR 1.13 = (95% CI = 0.98–1.29)). Conclusions: TN was associated with an elevated risk of cancers of the head, neck and nervous system including site-specific cancers in the area. Our results suggest the potential importance of smoking related tumors in TN, either as a symptom, cause or shared risk factor. [ABSTRACT FROM AUTHOR]

Botulinum toxin A (BT-A), a potential neurotoxin produced by the bacterium Clostridium botulinum, is known for its ability to prevent the release of acetylcholine at the neuromuscular synapse, leading to temporary muscle paralysis. BT-A is used for a wide range of therapeutic applications. Several studies have shown mechanisms beyond the inhibition of acetylcholine release for pain control. BT-A inhibits the release of neurotransmitters associated with pain and inflammation, such as glutamate, CGRP, and substance P. Additionally, it would be effective in nerve entrapment leading to neuronal hypersensitivity, which is known as a new pathogenesis of painful conditions. BT-A has been applied to the treatment of a wide variety of neurological disorders. Since 2010, BT-A application has been approved and widely used as a chronic migraine prophylaxis. Moreover, due to its effects on pain through sensory modulation, it may also be effective for other headaches. Several studies using BT-A, at different doses and administration sites for headaches, have shown beneficial effects on frequency and severity. In this review, we provide an overview of using BT-A to treat primary and secondary headache disorders. [ABSTRACT FROM AUTHOR]

Paroxysmal neurological symptoms in patients with multiple sclerosis (MS) have long been acknowledged. However, consideration of whether such symptoms are a clinical attack and sufficient for fulfillment of MS diagnostic criteria has varied as criteria have evolved over time. Previous studies and anecdotal reports indicate that some patients with MS first present with syndromes such as trigeminal neuralgia, Lhermitte's phenomenon, tonic spasm, and seizure years before an attack typical of MS such as optic neuritis or myelitis. We discuss four patients with presumed MS who initially presented with these syndromes with evidence of a corresponding central nervous system (CNS) lesion who, were these symptoms considered an attack, could have been diagnosed with relapsing remitting MS or clinically isolated syndrome. This case series aims to highlight the unmet need for data for such patient presentations and for clinical guidance from future MS diagnostic criteria to optimize care. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Herpes zoster is an acute cutaneous viral disease resulting from reactivation of dormant varicella‐zoster virus. The maxillary nerve is the least frequently affected branch of the trigeminal nerve. Rarely, cutaneous lesions can be secondarily infected with Klebsiella species. This report discusses a case of maxillary zoster with nasociliary nerve involvement and Klebsiella superinfection. [ABSTRACT FROM AUTHOR]

Trigeminal neuralgia (TN) is a debilitating condition characterized by excruciating facial pain resulting from dysfunction in the trigeminal nerve. Treatment options are limited. Noninvasive pulsed radiofrequency (PRF) therapy is an emerging promising approach to managing TN. This therapy provides pain control without tissue damage or unpleasant side effects compared to invasive procedures. Here, we present five cases of trigeminal neuralgia successfully managed with noninvasive PRF therapy. Our case series contributes to the existing literature and supports the potential efficacy of noninvasive PRF therapy for TN. [ABSTRACT FROM AUTHOR]

Objective Suprameatal tubercle (SMT), a bony prominence located above the internal acoustic meatus, is reported to impede the microscopic view during microvascular decompression (MVD) for trigeminal neuralgia (TN). For an enlarged SMT, removal of the SMT may be required in addition to the routine MVD to precisely localize the offending vessels. The objective of this study is to investigate the predictive factors influencing the requirement of SMT removal during trigeminal MVD. Methods We retrospectively reviewed 197 patients who underwent MVD for TN, and analyzed the correlation of the SMT height and other clinicosurgical data with the necessity to remove the SMT during MVD. The parameters evaluated in the statistical analyses included maximum SMT height, patient's clinical characteristics, surgical data including the type and number of offending vessels, and surgical outcomes. Results SMT removal was required for 20 patients among a total of enrolled 197 patients. In the univariate analysis, maximum SMT height, patient's age, and number (≥ 2) of offending vessels were associated with the requirement for SMT removal. Multivariate analysis with binary logistic regression revealed that the maximum SMT height and number (≥ 2) of offending vessels were significant factors influencing the necessity for SMT removal. A receiver operating characteristic curve analysis revealed that an SMT height ≥ 4.8 mm was the optimal cutoff value for predicting the need for SMT removal. Conclusion Large SMTs and the presence of multiple offending vessels are helpful in predicting the technical difficulty of trigeminal MVD associated with the necessity of SMT removal. [ABSTRACT FROM AUTHOR]

To compare whether there is a difference in the efficacy of complete endoscopic microvascular decompression (EVD) and microscopic microvascular decompression (MVD) in patients with classical trigeminal neuralgia (CTN). From January 2014 to January 2021, 297 CTN patients were assigned to the retrosigmoid approach EVD (138 cases) and the MVD groups (159 cases); to compare whether there are differences in the pain control rate, recurrence, complications of CTN patients between the 2operations, and separately predict the factors related to prognosis of both groups. There was no significant difference in painless rates at 1, 3, and 5 years after surgery (P = 0.356, P = 0.853, P = 1), and overall incidence of complications (P = 0.058) between the EVD and MVD groups. The EVD group had shorter surgical decompression duration than the MVD group (P < 0.001). The painless rate of patients with vertebrobasilar trigeminal neuralgia in the EVD group was higher than that in the MVD group, but the difference was not statistically significant (90% vs. 61.1%, P = 0.058). The independent risk factors associated with a good prognosis in the EVD group were a shorter course of the disease and severe neurovascular conflict, while severe neurovascular conflict is the only independent risk factor associated with a good prognosis in the MVD group. For CTN patients, compared with traditional MVD, EVD is also safe and effective and has the advantage of shorter decompression time.The predictive results of prognostic factors also suggest that CTN patients may benefit more from early surgical treatment. [ABSTRACT FROM AUTHOR]