Idiopathic Trigeminal Neuralgia Research Articles

Trigeminal neuralgia: drug therapy : The new German guideline

Trigeminal neuralgia is characterized by severe, lightning-like attacks of pain, which are mandatory for the diagnosis. The pain typically occurs on one side and is often triggered by simply touching the face, chewing or talking. In acute exacerbations, this can also hinder food and fluid intake, resulting in alife-threatening clinical picture. Adistinction is made between classical, secondary and idiopathic trigeminal neuralgia. For the diagnosis of trigeminal neuralgia, the medical history and imaging procedures are key for classification. The only active substances approved for the treatment of trigeminal neuralgia in Germany are carbamazepine and phenytoin, which is why off-label drugs often need to be used if there is no or insufficient effect or inacceptable side effects. Cooperation between research and clinical practice to improve the care of affected patients is therefore essential.

Clinical Depression and Anxiety Are Relieved by Microvascular Decompression in Patients with Trigeminal Neuralgia-A Prospective Patient-Reported Outcome Study.

Objective: Patients with idiopathic trigeminal neuralgia (TN) live in constant fear of triggering shock-like pain episodes, which may cause symptoms of depression and a reduction in quality of life. Microvascular decompressive surgery has been demonstrated to achieve satisfactory and stable results. With this study, we wanted to investigate prevalence and risk factors for depression and perceived stress in correlation with symptom relief after surgical treatment. Methods: In this prospective study, patients undergoing microvascular decompression (MVD) for TN were included. The Barrow Neurological Institute Pain Score (BNI), Beck Depression Inventory (BDI), Chronic Pain Acceptance Questionnaire (CPAQ), Perceived Stress Questionnaire (PSQ) and McGill questionnaire were used to evaluate depression, stress and anxiety disorders before and 3 months after MVD. Results: A total of 35 patients (16 male (46%)) with a mean age of 55.4 (SD 15) years were included in this study. The BDI revealed that 24 (68.8%) patients harbored mild-to-extreme depression preoperatively (2.4 ± 1.4), which improved to 1.2 (±0.6, p < 0.0001). Pain acceptance also changed from 64 (±11.3) to 67.7 (±9.3, p = 0.006). Perceived stress decreased from 46.9 (±21.9) to 19.6 (±18.6) (p < 0.0001) postoperatively, and pain decreased from 31.0 (±11.7) to 9.4 (±12.9, p < 0.0001). Microvascular decompression reduced the mean BNI pain score significantly from 4.6 to 1.8 postoperatively (p < 0.00001). Conclusions: Depression and perceived stress are prevalent in patients with idiopathic TN. Adequate treatment not only provides a high rate of satisfaction through pain relief, but also leads to immediate and significant improvements in depression and stress. Thus, in patients with TN who do not reach an adequate and timely pain reduction through medical management and develop signs of depression, early treatment with microvascular decompression should be considered.

Effectiveness and complication of low-dose trigeminal nerve block with alcohol in idiopathic trigeminal neuralgia

Effectiveness and complication of low-dose trigeminal nerve block with alcohol in idiopathic trigeminal neuralgia

Analyzing the Effect of Intraoperative Stimulation Voltage on Facial Numbness Following Radiofrequency Thermocoagulation in the Treatment of Idiopathic Trigeminal Neuralgia.

Radiofrequency thermocoagulation (RFT) effectively alleviates idiopathic trigeminal neuralgia (ITN); however, postoperative facial numbness poses a significant challenge. This issue arises due to the close proximity of high-temperature thermocoagulation, which not only ablates pain-related nociceptive fibers but also affects tactile fibers. Intraoperative sensory stimulation voltage (SV), which reflects the distance between the RFT cannula and the target nerve, potentially possesses the ability to prevent tactile fiber injury. This study aimed to investigate the influence of SV on postoperative facial numbness and provide valuable insights to mitigate its occurrence. A retrospective analysis was performed on 72 ITN patients with maxillary division (V2) pain who underwent RFT between 2020 and 2022. Among them, 13 patients with SV ≤ 0.2V constituted the low SV group. Subsequently, a matched-cohort analysis was conducted on the remaining 59 patients. The patients paired with the low SV patients were subsequently enrolled in the high SV group, adhering to a 1:1 match ratio. The primary outcome was the facial numbness scale assessment at 3days, 3months and 6months post-surgery. The pain intensity and medication burden served as the secondary outcomes. We successfully matched a cohort consisting of 12 patients in the low SV group and 12 patients in the high SV group. Each patient experienced various degrees of facial numbness at 3days post-RFT. Notably, the low SV group exhibited a higher incidence of moderate numbness (66.7% vs. 16.67%, P = 0.036), whereas the high SV group had more cases of mild numbness at the 6-month follow-up (25% vs. 83.3%, P = 0.012). Both groups demonstrated significant decreases in pain intensity and medication burden compared to before the operation. SV proved to be a reliable parameter for mitigating the degree of postoperative facial numbness in RFT treatment for ITN. A relatively high sensory SV ranging from 0.3 to 0.6V during the RFT procedure results in less facial numbness in the treatment of ITN.

Alterations in the spinal cord, trigeminal nerve ganglion, and infraorbital nerve through inducing compression of the dorsal horn region at the upper cervical cord in trigeminal neuralgia

BackgroundIdiopathic trigeminal neuralgia (TN) cases encountered frequently in daily practice indicate significant gaps that still need to be illuminated in the etiopathogenesis. In this study, a novel TN animal model was developed by compressing the dorsal horn (DH) of the upper cervical spinal cord. MethodsEighteen rabbits were equally divided into three groups, namely control (CG), sham (SG), and spinal cord compression (SCC) groups. External pressure was applied to the left side at the C3 level in the SCC group. Dorsal hemilaminectomy was performed in the SG, and the operative side was closed without compression. No procedure was implemented in the control group. Samples from the SC, TG, and ION were taken after seven days. For the histochemical staining, damage and axons with myelin were scored using Hematoxylin and Eosin and Toluidine Blue, respectively. Immunohistochemistry, nuclei, apoptotic index, astrocyte activity, microglial labeling, and CD11b were evaluated. ResultsMechanical allodynia was observed on the ipsilateral side in the SCC group. In addition, both the TG and ION were partially damaged from SC compression, which resulted in significant histopathological changes and increased the expression of all markers in both the SG and SCC groups compared to that in the CG. There was a notable increase in tissue damage, an increase in the number of apoptotic nuclei, an increase in the apoptotic index, an indication of astrocytic gliosis, and an upsurge in microglial cells. Significant increases were noted in the SG group, whereas more pronounced significant increases were observed in the SCC group. Transmission electron microscopy revealed myelin damage, mitochondrial disruption, and increased anchoring particles. Similar changes were observed to a lesser extent in the contralateral spinal cord. ConclusionIpsilateral trigeminal neuropathic pain was developed due to upper cervical SCC. The clinical finding is supported by immunohistochemical and ultrastructural changes. Thus, alterations in the DH due to compression of the upper cervical region should be considered as a potential cause of idiopathic TN.

Analyzing the risk factors of unilateral trigeminal neuralgia under neurovascular compression.

This study aimed to explore the risk factors and potential causes of unilateral classical or idiopathic trigeminal neuralgia (C-ITN) by comparing patients and healthy controls (HCs) with neurovascular compression (NVC) using machine learning (ML). A total of 84 C-ITN patients and 78 age- and sex-matched HCs were enrolled. We assessed the trigeminal pons angle and identified the compressing vessels and their location and severity. Machine learning was employed to analyze the cisternal segment of the trigeminal nerve (CN V). Among the C-ITN patients, 53 had NVC on the unaffected side, while 25 HCs exhibited bilateral NVC, and 24 HCs showed unilateral NVC. By comparing the cisternal segment of CN V between C-ITN patients on the affected side and HCs with NVC, we identified the side of NVC, the compressing vessel, and certain texture features as risk factors for C-ITN. Additionally, four texture features differed in the structure of the cisternal segment of CN V between C-ITN patients on the unaffected side and HCs with NVC. Our findings suggest that the side of NVC, the compressing vessel, and the microstructure of the cisternal segment of CN V are associated with the risk of C-ITN. Furthermore, microstructural changes observed in the cisternal segment of CN V on the unaffected side of C-ITN patients with NVC indicate possible indirect effects on the CN V to some extent.

Sphenopalatine Ganglion Block Using Intranasal Lignocaine Spray for Trigeminal Neuralgia: A Case Series

Abstract Various interventions have been tried for the management of trigeminal neuralgia which is a sharp, shooting recurrent neuropathic pain. The use of the sphenopalatine ganglion (SPG) block has been established as a fast, safe, and effective means of pain relief for these patients. Recently, 10% lignocaine spray has been described as a less invasive alternative for this block. We report seven patients of idiopathic trigeminal neuralgia with acute unilateral severe pain managed by SPG blocks using 10% intranasal lignocaine spray. Seven patients with unilateral trigeminal neuralgia were included in the study. Two puffs of 10% lignocaine were sprayed into the nostril of the affected side in a slightly medial and inferior direction. Before the procedure and 30 min later, Visual Analog Scale (VAS) scoring was done. The procedure was repeated in case of no pain relief after 1 h of nasal spray (VAS 4 or 5). All patients were observed for 2 h and oral medication was prescribed if required after assessment at 24 h. Four patients reported complete relief (VAS 0 or 1) and two of them reported pain (VAS 4 and 5) after 24 h. The procedure had to be repeated in two patients with no pain relief (VAS 4 and 5) after 1 h. There was no relief in one patient even after repeated administration (VAS 5). The findings suggest a role for intranasal lignocaine spray for SPG block in trigeminal neuralgia for alleviating acute exacerbations of pain and obtaining quick relief.

Comparison of microvascular decompression, percutaneous radiofrequency rhizotomy, and stereotactic radiosurgery in the treatment of trigeminal neuralgia: A long term quasi-experimental study.

Microvascular decompression (MVD), radiofrequency rhizotomy (RFR), and stereotactic radiosurgery (SRS) are surgical techniques frequently used in the treatment of idiopathic trigeminal neuralgia (TN), although the results reported for each of these are diverse. This study aimed to compare long-term pain control obtained by MVD, SRS, and RFR in patients with idiopathic TN. To compare the results obtained by MVD, SRS, and RFR we chose a quasi-experimental, ambispective design with control groups but no pretest. A total of 52 participants (MVD n = 33, RFR n = 10, SRS n = 9) were included. Using standardized outcome measures, pain intensity, pain relief, quality of life, and satisfaction with treatment were assessed by an independent investigator. The TREND statement for reporting non-randomized evaluations was applied. Clinical outcomes were evaluated at the initial postoperative period and at 6 months, 1, 2, 3, 4, and 5 years postoperatively. MVD has shown better results in pain scales compared to ablative procedures. Significant differences between groups were found regarding pain intensity and pain relief at the initial postoperative period (p < 0.001) and 6 months (p = 0.022), 1 year (p < 0.001), 2 years (p = 0.002), and 3 years (p = 0.004) after the intervention. Those differences exceeded the thresholds of the minimal clinically important difference. A higher percentage of patients free of pain was observed in the group of patients treated by MVD, with significant differences at the initial postoperative period (p < 0.001) and 6 months (p = 0.02), 1 year (p = 0.001), and 2 years (p = 0.04) after the procedure. Also, a higher risk of pain recurrence was observed in the RFR and SRS groups (HR 3.15, 95% CI 1.33-7.46; p = 0.009; and HR 4.26, 95% CI 1.77-10.2; p = 0.001, respectively) compared to the MVD group. No significant differences were found in terms of quality of life and satisfaction with treatment. A higher incidence of complications was observed in the MVD group. Concerning pain control and risk of pain recurrence, MVD is superior to RFR and SRS, but not in terms of quality of life, satisfaction with treatment, and safety profile.

Frameless Linear Accelerator (LINAC) Based Radiosurgery (SRS) vs. Framed Gamma Knife SRS for Idiopathic Trigeminal Neuralgia (TN)

Stereotactic radiosurgery (SRS) is an effective treatment for idiopathic trigeminal neuralgia (TN). Conventional treatment is done through frame-based solution due to small target and high radiation dose. More recently, LINAC based frameless SRS technique has been established as a patient friendly alternative. Herein we compared our single institution experience of LINAC based frameless SRS vs frame-based gamma knife SRS for TN. The hypothesis is LINAC based frameless SRS can provide equivalent dosimetric and clinical outcome as compared frame-based gamma knife treatment. Patients with idiopathic TN who received SRS treatment (LINAC based frameless treatment or Gamma knife framed treatment) at our institution from 2015-2022 were included. A minimum follow up of 1 year was required. Patient data was extracted from electronic medical records and radiation treatment planning system. Pain intensity was evaluated utilizing a modified 0-4 Barrow Neurological Institute (BNI) pain intensity score, and then dichotomized where BNI score 0-2 represented response to treatment and BNI score 3-4 represented no response. Statistical analysis was conducted with a linear regression model accounting for race, gender, prior pain, pain distribution including laterality and branch involvement, medication regimen at time of treatment, previous radiation treatment, and prior procedures. Response was then compared between both modalities overall and within each sub-group with chi-square testing and linear regression. A total of 81 patients were identified, 14 patients were excluded due to lack of adequate follow-up, leaving 67 for analysis. 12 (17.9%) were male and, 55 (82.1%) were female. All patients were managed with medication prior to SRS treatment. 5 (7.5%) had rhizotomy and 13 (19.4) had microvascular decompression, and 8 (11.9%) had previous gamma-knife radiosurgery prior to SRS treatment at our institution. Of the 67 patients, 23 (34.3%) received frame-based gamma knife SRS, 44(65.7%) received frameless LINAC treatment. 58 (86.6%) radiation naïve patients received 90 Gy in 1 fraction, while out of the 9 who had previously had intracranial radiation treatment 7 (10.4%) received 70 Gy and 2 (3%) received 80 Gy all prescribed to 100% isodose line. All patients were treated with 4 mm cone. There was no significant difference in brainstem dose between these two techniques. Between LINAC-based or Gamma Knife modalities rate of pain control (77.3 % vs 82.6 %, respectively, p = 0.61) as well as toxicity in facial numbness (31.8% vs 21.7%, respectively, p = 0.38) showed no statistical difference. There was no statistically significant signal (p > 0.05) detected within the subgroups analyzed. The linear regression model also showed no significant difference. LINAC based frameless SRS provides comparable dosimetry and pain control for TN as compared to frame-based gamma knife treatment. It is a patient friendly solution for patients with TN.

Meckel’s cave compression with Teflon for the treatment of idiopathic trigeminal neuralgia: its possibility as a modified surgical technique

Objective: We analyzed the clinical outcomes of Meckel’s cave compression with Teflon (Rhee’s method) as a new modified and additional surgical technique for trigeminal neuralgia (TN).Methods: Between March 1996 and December 2014, out of 78 patients who were treated with microvascular decompression (MVD) or partial sensory root rhizotomy, 28 patients additionally underwent Meckel’s cave compression with Teflon. The mean age at initial treatment was 54.3 years (range: 40–69 years). The mean duration from onset to operation was 70.5 months (range: 5–360 months) and the mean follow-up period was 26 months (range: 1–77 months). Results: Fifteen patients (53.6%) had facial pain in the V2/V3 distribution. The offending or associating vessel was the superior cerebellar artery in four patients (14.3%), the superior petrosal vein in six (21.4%), the anterior inferior cerebellar artery in two (7.1%), multiple vessels in nine (32.1%), and miscellaneous arteries or veins in six (21.4%). One patient (3.6%) had no offending vessel, and seven patients were had no definite offending vessels that contacted the trigeminal root entry zone. Meckel’s cave compression with Teflon was applied to all patients: 10 (35.7%) in combination with MVD, one (3.6%) with partial rhizotomy, and 17 (60.7%) with both MVD and partial rhizotomy. TN was relieved in 26 patients (92.9%) and symptoms recurred in three patients (pain-free rate: 82.1%). The complication rate of this method appeared to be similar to other treatment procedures. Conclusion: Meckel’s cave compression with Teflon may be a safe and useful additional treatment procedure for TN.

The Comparison of General Characteristics and Early and Late Post-intervention Results in Patients With Trigeminal Neuralgia Secondary to Multiple Sclerosis and Idiopathic Trigeminal Neuralgia Treated With Radiofrequency Thermocoagulation.

Aim The aim of this study was to investigate possible differences (in terms of demographic structure, disease history, complaints, clinical findings, early and late treatment outcomes, and complications) between patients with idiopathic trigeminal neuralgia (ITN) and trigeminal neuralgia (TN) secondary to multiple sclerosis (MS) who were admitted to our clinic and underwent radiofrequency (RF) thermocoagulation procedure. Materials and methods Patients who underwent percutaneous radiofrequency thermocoagulation with a diagnosis of trigeminal neuralgia by a single neurosurgeon in a single neurosurgery clinic between January 2005 and January 2020 were included in this study. Patients were divided into two groups: idiopathic trigeminal neuralgia and trigeminal neuralgia secondary to multiple sclerosis (MSTN) according to their diagnosis. In our study, 215 TN patients who underwent 286 procedures were included. These patients were categorized according to age, sex, involved side, pain localization, and pain history. Postoperative complications were determined after each intervention. The early and late results of all interventions were evaluated, and the results were compared between both groups. All results were statistically analyzed. Results Considering the age of the patients, the mean age of the idiopathic group was higher than the multiple sclerosis group (58.18>49.46). In terms of the side of pain, bilateral involvement was significantly more common in the MS secondary group (1.48%<30.77%). There was no significant difference between the early results of both groups. In terms of remission periods, the pain-free period in the MS secondary group was significantly shorter than in the idiopathic group (mean value in months, 30.87>23.81). Conclusion The radiofrequency thermocoagulation of the trigeminal nerve is a highly effective, low-complication, reproducible procedure for trigeminal neuralgia, but the search for ways to improve the efficacy of treatment in MS patients should continue.

The Correlation between Trigeminal Neuralgia and Local Anesthetics Neurotoxicity Associated with Acute Inflammation: A Cross-sectional Study

Background: Trigeminal neuralgia (TN) represents a subject of importance in oral medicine due to the large number of patients complaining of TN who are aware that the orofacial pain has a dental origin and therefore seek initial care from the dentist. The reasons for the majority of TN cases remain controversial, but nearly 10% of patients have an obvious pathological condition, such as intracranial pathology. Aim: This study aimed to assess the correlation between idiopathic trigeminal neuralgia and local anesthetic overdose and/or repeated injections caused by dental malpractice. Patients and Methods: An adequate sample of thirty-four patients was selected from the teaching clinic of oral medicine in the College of Dentistry, the University of Karbala, Iraq. All patients were fit for the inclusion criteria and subjected to a thorough oral examination to exclude any organic diseases that cause orofacial pain. Also, they were subjected to a medical examination by multiple neurologists using magnetic resonance imaging and other medical investigations to ensure that all patients did not suffer from intracranial pathology. Results: The patients were statistically distributed by their ages into two sub-groups. The first group (25-48 years old) represented 52.94% of all patients, and the second group (49-72 years old) included 47.06%. The percentage of disease according to sex was 79.4% in males and 20.6% in females. 3-6 dental carpules containing lidocaine (2%) with epinephrine were given to patients. The data of the studied sample were analyzed by using the statistical package of social sciences (SPSS) version 25. The chi-square test was used to test the effect of the type of dental procedure before pain in the two age groups and the two sex groups. For the age group, the difference was significant (p-value &lt; 0.05), which indicated an increased incidence of nerve damage caused by local anesthesia in older patients. For the sex group, the chi-square test exhibited a value of 2.45, with no significant difference (p-value &gt; 0.05). The main theory suggested for the occurrence of local neuropathies and the initiation of TN was the demyelination of nerve, which may be due to the neurotoxic effects of local anesthesia administered at high concentrations and for prolonged exposure times (repeated injections at the site of the dental infection after failure of LA) that may activate the intrinsic pathway of apoptosis through cytochrome C release. The local anesthetic-related neurotoxicity has thus been found to have harmful effects on the nerve tissue, including demyelination and axonal degeneration. Conclusion: The malpractice of local anesthesia in dentistry may lead to dysesthesia, allodynia, and trigeminal neuralgia with different degrees and severity due to the neurotoxicity of the peripheral nerve fiber. The nerve damage may occur in many forms, such as demyelination, apoptosis, axonal degeneration, and hypoxia due to thrombosis. So, dentists should recognize the risk of repeated injections or high dose solution (4%) of LA in the inflamed tissues when inducing analgesia for their dental operations that might initiate the primary trigeminal neuralgia.

Twitchy Pain of Left Face: A Rare Case of Idiopathic Trigeminal Neuralgia after Tooth Extraction in a Young Child

Introduction: Idiopathic Trigeminal neuralgia in children is a rare case presentation that poses a challenge in dental practice. This case involved a sequence of multi-management by several departments including Paediatric Dentistry, Oral Maxillofacial Surgery (OMFS), Otorhinolaryngology (ORL) and Paediatric Neurology. Case description: A 10-year-old girl was referred initially to the Paediatric Dentistry Specialist Clinic, School of Dental Sciences, Universiti Sains Malaysia (USM), Malaysia with the complaint of left facial pain associated with muscle twitching, weakness and swelling for five days prior to this first visit. There was a history of tooth extraction of her lower left second primary molar on the day before the episode of left facial pain and twitching. Clinical examination showed left facial involuntary twitching with visual analogue scale (VAS) pain score of 8, some evidence of left facial weakness, numbness but no facial swelling. No significant finding on the intraoral examination, including good healing signs at the exodontia site. The investigations included orthopantomography, Cranial Nerves II-XII examination and tests, blood investigations, Blood Urea and Serum Electrolyte (BUSE), electromyography (EMG) and electroencephalogram (EEG). The final diagnosis was left Idiopathic Trigeminal Neuralgia that is associated with tooth extraction. After a period of a month, the symptoms and signs were gradually reduced and ceased by taking oral medications such as Baclofen, Neurobion and Gabapentin. Joint management from multi-departments with close follow ups help to provide the conservative and safe treatment for this patient.

Magnetic resonance-guided focused ultrasound central lateral thalamotomy against chronic and therapy-resistant neuropathic pain: retrospective long-term follow-up analysis of 63 interventions.

Medial thalamotomies were introduced in the late 1940s. Pain relief was shown to be achieved for all body locations. With some exceptions, these early relatively small series showed frequent, more or less complete recurrence of the original pain. The posterior part of the central lateral nucleus in the human medial thalamus was identified in the 1990s using multiarchitectonic studies and intraoperative single-cell recordings and was confirmed as a surgical target. This retrospective patient series extended over 11 years. Its goal was to demonstrate the efficacy and risk profile of the MR-guided focused ultrasound (MRgFUS) central lateral thalamotomy (CLT) against chronic and therapy-resistant neuropathic (i.e., neurogenic) pain. In this single-center, nonrandomized retrospective cross-sectional analysis of consecutive patients, 63 consecutive MRgFUS CLT interventions were performed in 55 patients. The mean follow-up duration was 55 months. A total of 112 CLT targets were performed, and the CLT was applied bilaterally in 48 patients and contralateral to their pain in 7 patients. Repeat MRgFUS interventions were performed in 8 patients. One serious adverse event with numbness of the upper lip was recorded. The mean pain relief rated by patients was 42% ± 32% at 3 months, 43% ± 36% at 1 year, and 42% ± 37% at the last follow-up (n = 63). The proportions of cases with ≥ 30% pain relief were 65% at 3 months, 63% at 1 year, and 61% at the last follow-up. Good outcomes (≥ 50% pain relief) were found in 54% of patients at 3 months, 49% at 1 year, and 51% at the last follow-up. The reduction in mean VAS scores showed similar percentage reductions as those for pain relief (-41% for continuous pain and -49% for pain attacks) at the 1-year follow-up. The mean frequency of pain attacks was reduced by 92%. Allodynia was reduced or suppressed in 68% of patients and never appeared de novo after MRgFUS CLT. These results suggest that MRgFUS CLT against neuropathic pain is a safe approach and its results are stable over time. At a mean follow-up duration of 55 months, the mean pain relief was 42% and more than 50% of patients still reported ≥ 50% pain relief. Patients with classical and idiopathic trigeminal neuralgia reported a higher mean pain relief compared with the whole patient group.

Percutaneous glycerol rhizolysis of the trigeminal ganglion for the treatment of idiopathic and classic trigeminal neuralgia: Outcomes and complications.

Patients with idiopathic trigeminal neuralgia (TN) with absent arterial contact or venous contact only and classic TN with morphological changes of the trigeminal nerve secondary to venous compression are not routinely recommended microvascular decompression at our institution. In patients with these anatomical subtypes of TN, limited data exists describing the outcomes of percutaneous glycerol rhizolysis (PGR) of the trigeminal ganglion (TG). We performed a retrospective single-center cohort study and analyzed outcomes and complications after PGR of the TG. Clinical outcome after PGR of the TG was assessed via the Barrow Neurological Institute (BNI) Pain Scale. Forty-five patients underwent a total of 66 PGRs of the TG. At short-term follow-up, 58 procedures (87.9%) resulted in a BNI score of I (i.e., freedom from pain without medication). At a median follow-up of 3.07 years, 18 procedures (27.3%) resulted in a BNI score of I, 12 procedures (18.1%) resulted in BNI score of IIIa, and 36 procedures (54.5%) resulted in a BNI score of IIIb-V. The median length of freedom from pain without medication was 1.5 years. Eighteen procedures (27.3%) caused hypesthesia and two (3.0%) caused paresthesias. There were no serious complications. In patients with these anatomical subtypes of TN there was a high rate of short-term pain relief for the first 1-2 years and thereafter a large proportion of patients experienced pain relapse. In this patient group, PGR of the TG represents a safe procedure that is efficacious in the short term.

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

BackgroundIt 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.MethodsIn 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.ResultsA 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.DiscussionThe 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.

Comparison of the blink reflex in classical and idiopathic trigeminal neuralgia

Background Previous findings indicate that the blink reflex is useful to distinguish between primary (classical/idiopathic) and secondary trigeminal neuralgia. No prior studies have investigated whether the blink reflex could identify differences in electrophysiological responses between classical and idiopathic trigeminal neuralgia. With this in mind, we investigated the blink reflex in a cohort of classical and idiopathic trigeminal neuralgia patients. Methods Participants were consecutively enrolled in the study. According to magnetic resonance imaging findings, the patients were subgrouped into either classical or idiopathic trigeminal neuralgia. Assessors were blinded to the subgroup and pain side, and the blink reflex was examined to assess R1 and R2 latencies, as well as the area under the curve. Results The study group constituted of 55 patients with primary trigeminal neuralgia: 25 patients with classical trigeminal neuralgia and 30 patients with idiopathic trigeminal neuralgia. None of the blink reflex latencies (R1 and R2) or the area under the curve significantly differed between the two subgroups when adjusted for age and sex ( p &gt; 0.05). Conclusions Our findings suggest that the blink reflex cannot be used to differentiate classical and idiopathic trigeminal neuralgia patients, and that both subgroups may share common pathophysiological mechanisms. Trial Registration: ClinicalTrials.gov Identifier: NCT05328661.

Botulinum toxin A and neuropathic pain: An update

Botulinum toxin type A is a widely used neurotoxin for the treatment of muscle hyperactivity such as dystonia and spasticity. Several clinical trials have also reported an efficacy of subcutaneous or intradermal administrations of botulinum toxin A on various neuropathic pain conditions including idiopathic trigeminal neuralgia and found that specific sensory phenotypes were predictors of the response. This narrative review summarizes the potential mechanisms of action, efficacy and safety of botulinum toxin A in neuropathic pain as well as its place in the therapeutic algorithm of neuropathic pain.

Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go.

Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.

ZAPTed (Zygomatic Arch and Point Triggers) Protocol for Botulinum Toxin Injections in the Management of Refractory Trigeminal Neuralgia (P11-12.007)

<h3>Objective:</h3> To assess the clinical effects of botulinum toxin type A injections in patients with refractory idiopathic trigeminal neuralgia. <h3>Background:</h3> Botulinum toxin type A (BTX-A) has been reported as being effective in the management of TN when injected sub-cutaneously along the trigeminal branches or into trigger points or below the zygomatic arch in doses ranging from 25 to 170 units. <h3>Design/Methods:</h3> We had 5 patients with refractory idiopathic TN, all female, with ages ranging from 27 – 61 years of age. The mean duration of pain was 98 months (8.1 years). All patients had increased sensitivity to touch over the maxillary region of the face, with disabling pain, despite receiving appropriate treatments for TN. 2 patients were considered candidates for decompression surgery, but preferred not to proceed. A maximum of 35 units of BTX-A was injected intra-dermally with 10 units being injected just below the zygomatic arch and the other 25 units into painful facial triggers points in a grid-like fashion, approximately 2 cm apart. - “<b>ZAPTed” injection protocol</b>. The patients’ response to BTX-A was evaluated using the Numerical Rating Scale (NRS) and also the number of attacks per day, before and after BTX-A. <h3>Results:</h3> All patients obtained relief of pain and reduced sensitivity to touch in the trigger points. The mean NRS was 8.6 at baseline and 1.0 at week 8. The mean number of paroxysms of pain reduced from 40 episodes of pain per day at baseline to 0.12 per day at week 8. The mean duration of effect was 16.8 weeks. Transient facial asymmetry was seen only in 1 patient after the first injection. <h3>Conclusions:</h3> This study provides further support for the use of BTX-A in the treatment of TN. The effect can be long lasting and repeated, when required. The injections are well tolerated as the lower doses used. <b>Disclosure:</b> Prof. Aggarwal has nothing to disclose.