Symptomatic Trigeminal Neuralgia Research Articles

Trigeminal neuralgia at the present stage: Pathophysiology, classification, diagnosis and treatment (literature review)

The incidence of trigeminal neuralgia (TN) is 4–5 cases per 100,000 population per year, and the prevalence is about 20–50 cases per 100,000 population. According to the modern classification, the following types of TN are distinguished: classical, symptomatic and idiopathic. The cause of classical TN is a neurovascular conflict, of symptomatic TN – neoplasms in the petroclival area, vascular anomalies, multiple sclerosis, etc. In the absence of a reliable etiological factor, TN is considered idiopathic. TN pathogenesis remains one of the most challenging topics in neuroscience. Today, there are many theories and hypotheses regarding the peripheral and central mechanisms of trigeminal neuralgia. The most popular theory is the neurovascular conflict that occurs between the trigeminal nerve and the cerebral vessels, but this theory is not the only one. It is known that even after microvascular decompression, patients may continue to experience facial pain. Therefore, other pathogenetic mechanisms are discussed: short circuit theory, multineuronal mechanism, allergic and immune hypothesis, gate theory, bioresonance hypothesis, trigeminal convergence projection theory, “ignition” hypothesis and ion channel pathology. TN is a clinical diagnosis, and its establishing requires certain criteria proposed by the International Headache Society. Using instrumental research methods, namely magnetic resonance imaging of the brain, is necessary for the differential diagnosis of classical and symptomatic TN, and imaging results should always be interpreted in combination with clinical data to make correct decisions on further treatment tactics.

Management outcomes of peripontine arteriovenous malformation patients presenting with trigeminal neuralgia.

Trigeminal neuralgia as the presenting symptom of brain arteriovenous malformation (bAVM) has been rarely reported. Treatment of reported cases has been skewed toward surgery for these scarce, deeply located bAVMs. Here, the authors report their management and outcomes of bAVM patients presenting with ipsilateral trigeminal neuralgia (TN) at their institution. This is a retrospective cohort study. The authors' institutional bAVM database was queried for non-hereditary hemorrhagic telangiectasia bAVMs in pontine, cistern, brainstem, trigeminal nerve, or tentorial locations. Patients with complete data were included in a search for trigeminal neuralgia or "facial pain" as the presenting symptom with TN being on the same side as the bAVM. Demographics, TN and bAVM characteristics, management strategies, and outcomes of bAVM and TN management were analyzed. Fifty-seven peripontine bAVMs were identified; 8 (14.0%) of these bAVMs were discovered because of ipsilateral TN, including 4 patients (50%) with facial pain in the V2 distribution. Five patients (62.5%) were treated with carbamazepine as the initial medical therapy, 2 (25%) underwent multiple rhizotomies, and 1 (12.5%) underwent microvascular decompression. None of the patients with TN-associated bAVMs presented with hemorrhage, compared with 25 patients (51%) with bAVMs that were not associated with TN (p < 0.01). TN-associated bAVMs were overall smaller than non-TN-associated bAVMs, but the difference was not statistically significant (1.71 cm vs 2.22 cm, p = 0.117), and the Spetzler-Martin grades were similar. Six patients (75%) underwent radiosurgery to the bAVM (mean dose 1800 cGy, mean target volume 0.563 cm3) and had complete resolution of TN symptoms (100%). The mean time from radiosurgery to TN resolution was 193 (range 21-360) days, and 83.3% of treated TN-associated bAVMs were obliterated via radiosurgery. Two patients (12.5%) were recommended for conservative management, with one undergoing subsequent rhizotomies and another patient died of hemorrhage during follow-up. TN-associated bAVM is a rare condition with limited evidence for management guidance. Radiosurgery can be safe and effective in achieving durable TN control in patients with TN-associated bAVMs. Despite their deep location and unruptured presentation, obliteration can reach 83.3% with radiosurgery.

Repeat Microvascular Decompression for Recurrent Trigeminal Neuralgia.

To review our experience with patients presenting with recurrent trigeminal neuralgia (TN) and who have undergone repeat microvascular decompression surgery (rMVD). This retrospective observational study was conducted at the Department of Neurosurgery at a university hospital. Patients who initially experienced complete pain relief after the first MVD but later had a recurrence of TN symptoms which required an rMVD were included in the study. Pain control outcomes were evaluated based on the Barrow Neurological Institute (BNI) scale score. Of the 375 patients who underwent MVD for TN over a 20-year period, 19 patients (6 females and 13 males) with a mean age of 57.68 ± 9.78 years developed symptom recurrence which necessitated an rMVD (5.06%). The average duration of the symptoms before the rMVD was 16.1 ± 19.36 months. The mean BNI score of the patients before the rMVD was 4.5 ± 0.5. Recurrence was primarily attributed to compression by a new offending vessel (n=9, 47.4%) or a Teflon granuloma (n=8, 42.1%). Two patients (10.5%) did not have any identifiable compression. During a follow-up period of 106.3 ± 58.3 months, excellent pain relief (BNI-I) was achieved in 10 patients (52.6%). Eight patients (42.1%) experienced a good outcome (BNI-III), and one patient (5.3%) experienced a poor outcome (BNI-IV). Recurrence of TN symptoms can occur even after an initially successful MVD. Subsequent MVDs should be considered as the primary treatment option for recurrent TN, as it significantly controls pain with low morbidity.

GFAP-NpHR mediated optogenetic inhibition of trigeminal nucleus caudalis attenuates hypersensitive behaviors and thalamic discharge attributed to infraorbital nerve constriction injury

The significance of hyperactive astrocytes in neuropathic pain is crucial. However, the association between medullary astrocytes and trigeminal neuralgia (TN)-related pain processing is unclear. Here, we examined how optogenetic inhibition of medullary astrocytes in the trigeminal nucleus caudalis (TNC) regulates pain hypersensitivity in an infraorbital nerve (ION) constricted TN model. We used adult Sprague Dawley rats subjected to infraorbital nerve (ION) constriction to mimic TN symptoms, with naive and sham rats serving as controls. For in vivo optogenetic manipulations, rats stereotaxically received AAV8-GFAP-eNpHR3.0-mCherry or AAV8-GFAP-mCherry at the trigeminal nucleus caudalis (TNC). Open field, von Frey, air puff, and acetone tests measured pain behavioral flexibility. In vivo thalamic recordings were obtained simultaneously with optogenetic manipulation in the TNC. Orofacial hyperalgesia and thalamic hyperexcitability were both accompanied by medullary astrocyte hyperactivity, marked by upregulated GFAP. The yellow laser-driven inhibition of TNC astrocytes markedly improved behavioral responses and regulated thalamic neuronal responses. Halorhodopsin-mediated inhibition in medullary astrocytes may modify the nociceptive input transmitted through the trigeminothalamic tract and pain perception. Taken together, these findings imply that this subpopulation in the TNC and its thalamic connections play a significant role in regulating the trigeminal pain circuitry, which might aid in the identification of new therapeutic measures in TN management.Graphical

Purgation therapy (bhedhi) in the treatment of Trigeminal neuralgia and evaluation using Siddha diagnostic tool neerkuri and neikuri – A Case study

Siddha science is an immortal science, which has its origin from ‘Siddhars’. The Siddha system is mainly based on the humoral theory. The three humors namely Vatham, Pitham and Kapham. Any increase or decrease in the ratio of the three humors causes disease in the human body. In the Siddha system of medicine, diseases are classified into 4448 in number. Out of these Yugi Munivar classified Vatham as 80 types. The symptoms of Trigeminal Neuralgia come under this Vatha classification. The elevated Vatham is decreased by giving purgation therapy based on the quote ‘Bhedhiyaal Vatham Thaalum’. Agasthiyar Kuzhambu is one of the best commonly used purgative medicine in the Siddha System.Trigeminal neuralgia is one of the painful disorders involving the fifth cranial nerve and causes severe unilateral pain in the face over regions supplied by the branches of the trigeminal nerve[5]. The present study is conducted to know the efficacy of Siddha Purgation Therapy for the management of trigeminal neuralgia on the basis of the quote “Bhedhiyaal Vatham Thaalum”. A female patient of 56 years, diagnosed with trigeminal neuralgia approached our hospital and got purgation therapy using Agasthiyar Kuzhambu for 3 days. Patient complaints were assessed before and after treatment with 1) Siddha diagnostic tool neerkuri and neikuri, 2) Questionnaire about increased Vatha symptoms and 3)Visual Analog Scale (VAS) pain scale. After giving Agasthiyar Kuzhambu follow up the patient she got relieved from their symptoms and got satisfactory results with the Siddha line of management. The possible understanding of the case and therapeutic protocol in Siddha has been discussed.

Management of trigeminal neuralgia: A multi-centre case study in general practice

Background and aims Patients often first present with symptoms of trigeminal neuralgia (TN) to primary care. However, there has been little research to determine whether the diagnosis and management of this condition is carried out according to current guidelines. Furthermore, there is little up-to-date information regarding the prevalence of TN in the UK. The aim is to estimate the prevalence of TN and to audit the diagnosis and management process of TN in primary care. Methods Between 2019 and 2020 a search was made at five UK GP practices with a total patient population of 55,842 using EMIS and SystmOne patient record systems to review patient consultations to identify patients coded with TN or facial pain (FP). These records were reviewed to ascertain the basis for diagnosis, management in primary care and referral to secondary care. Results 157 patients were identified; 54 coded with FP and 103 with TN. These results indicate a prevalence of 22.3 in 10,000. There was no difference in documented symptoms between the two groups. Seven patients had all ICDH3 criteria recorded, with two meeting the requirements for TN diagnosis. 58.8% of patients with TN were started on carbamazepine, the current gold standard treatment, compared with 16.7% in the FP group. 38.2% of TN patients were referred to a range of different specialities. Conclusion The prevalence of TN may be higher than previously thought. Key diagnostic criteria are often omitted, leading to potential misdiagnosis or delays in diagnosis. Relatively few referrals are made, though all patients should be considered for imaging.

Recrudescing Trigeminal Neuralgia: A Chronicle of Orofacial Pain Before and After Cervical Cord Compression: A Case Report

BACKGROUND: Classic trigeminal neuralgia is a clinical condition with pathognomonic acute and sporadic episodes of pain. Atypical trigeminal neuralgia manifests more dull, constant, and chronic with occasional acute burning or stabbing pain as experienced in classic trigeminal neuralgia. There have been reports of trigeminal neuralgia developing after cervical insults, positing a cervical source of orofacial pain. CASE REPORT: We report a patient with chronic, bilateral atypical trigeminal neuralgia symptoms due to a cervical cavernous malformation who underwent a C3-C6 laminectomy with cavernous malformation resection and had subsequent seroma-induced bilateral classic trigeminal neuralgia. Therapist-led cervical exercises improved his symptoms. His quality of life and function independence improved and his medications were titrated down. CONCLUSIONS: In conclusion, trigeminal neuralgia does not always present as classic paroxysmal, electrical pain and can occur from a cervical insult distal to the C2 spinal level. KEY WORDS: Trigeminal neuralgia, cervical cord compression, case report

Effects of Peripheral Nerve Injury on the Induction of c-Fos and Phosphorylated ERK in the Brainstem Trigeminal Sensory Nuclear Complex.

Sequential changes in brainstem and spinal cord neurons after traumatic injury to peripheral nerves are related to neuropathic pain symptoms. This study was conducted to elucidate the influence of nerve insult on stimulus-induced c-Fos expression and ERK phosphorylation by brainstem neurons. The brainstem trigeminal sensory nuclear complex (BTSNC) was examined for neuronal profiles immunolabeled with c-Fos and phosphorylated ERK (p-ERK) antibodies elicited by stimulation of the tongue with capsaicin after lingual or inferior alveolar nerve (IAN) injury. Abundant neuronal profiles immunolabeled for c-Fos and p-ERK elicited by capsaicin were distributed in the spinal trigeminal nucleus caudalis (Vc) without nerve injury. The spinal trigeminal nucleus oralis (Vo) contained limited numbers of these neuronal profiles after stimulation of the tongue. A significant reduction of these neuronal profiles in the ipsilateral Vc was detected after lingual nerve injury. After IAN injury, an increased number of neuronal profiles immunolabeled for c-Fos elicited by capsaicin was noted, while that of p-ERK was left unchanged in the ipsilateral Vc. On the both sides of the Vo, an increased number of capsaicin-induced neuronal profiles immunolabeled for c-Fos and p-ERK was detected after lingual or IAN injury. Differential effects of lingual or IAN injury on stimulus-induced c-Fos expression and ERK phosphorylation by Vo and Vc neurons may be involved in the complex nature of symptoms of trigeminal neuralgia.

The Role of Magnetic Resonance Imaging in the evaluation of Trigeminal Neuralgia: a pilot study

Introduction Trigeminal neuralgia is a debilitating painful condition affecting one or more branches of trigeminal nerve characterized by sharp shooting, electric shock like pain lasting for a short time. In most cases, no specific cause can be identified but certain do tend to occur due to lesions or damage to the trigeminal nerve due to vascular compression, tumors, etc. which can be detected by magnetic resonance imaging. Hence, this pilot study was conducted to identify any underlying causes for trigeminal neuralgia using magnetic resonance imaging. Methods A prospective cross-sectional descriptive study was conducted on 10 patients who were presented to department with clinical symptoms of trigeminal neuralgia. Magnetic resonance imaging of the brain with trigeminal protocol was conducted. The evaluation of the entire course of the trigeminal nerve was then performed by an experienced radiologist. Results Out of the 10 patients, 6 were females and 4 males. Four patients did not show presence of any pathology i.e. were idiopathic. Five cases reported with neurovascular compression and one showed the presence of a tumor at the cerebellopontine angle compressing the nerve. Conclusion In this study, with use of magnetic resonance imaging, a 60% occurrence of an underlying pathology was demonstrated which could be treated to relieve the neuralgia. Hence, taking into account the high prevalence of etiological factors which could contribute towards trigeminal neuralgia detected on MRI, large scale studies can be considered for the same.

Electroacupuncture in The Treatment of Trigeminal Neuralgia Pain

Objective: This case report aimed to examine the effectiveness of electroacupuncture (AE) in treating trigeminal neuralgia pain and improving overall health in a 43-year-old woman. Methods: The study protocol involved administering electroacupuncture to the patient twice a week for a period of four consecutive weeks. During each treatment session, needles of size 0.30x60mm were inserted into specific acupoints on the patient's face, including ST8 (Touwei), GB14 (Yangbai), SJ23 (Sizhukong), EX-HN5 (Taiyang), GB3 (Shangguan), SI18 (Quanliao), ST7 (Xiaguan), and ST6 (Jiache), using the acupoint-to-acupoint penetrative needling technique. Results: The results of this case report indicate that following eight treatments with electroacupuncture, the patient's pain was completely resolved. Additionally, the patient reported improvements in overall health, including increased energy levels, positive mood, deeper sleep, and a return to normal appetite. Furthermore, the function of the trigeminal nerve, which was previously impaired, was restored. Conclusions: This case report suggests that electroacupuncture (AE) may be an effective treatment for relieving the clinical symptoms of trigeminal neuralgia and improving trigeminal nerve function. The results of this study support the high clinical application value of AE in the treatment of this condition.

A Nod for Meckel: A Novel Surgical Position Utilizing Meckel's Cave Anatomy for Percutaneous Glycerol Rhizotomy in Trigeminal Neuralgia.

Objective We aim to describe a novel positioning technique using a specific surgical table to achieve the optimal angle during percutaneous glycerol rhizotomy (PGR) for trigeminal neuralgia (TN). Design This is a descriptive and photographic analysis of successful cases for future implementation. Setting This study was conducted at a single-institution, academic center. Participants The participants were adult patients with TN who underwent PGR and provided consent for publication. Main Outcome Measures Primary outcomes of this study were TN symptomatic relief and surgical complications. Results The use of a beach chair sliding headboard surgical table for PGR is plausible and ensures precise and immobile head flexion for 1 hour postglycerol injection. There were no intraoperative or postoperative complications. All patients achieved successful reduction of TN symptoms. Conclusions Utilizing this new method of intraoperative navigation with a unique surgical table in the upright position, surgeons may achieve precise head adjustments post-PGR. Head flexion has been postulated as a means of ensuring glycerol containment in Meckel's cave. This method can help standardize this procedure for future systematic studies on the importance of head positioning post-PGR.

Диференційна діагностика больового синдрому в щелепно-лицевій ділянці. Аналіз клінічного випадку

The purpose of the study was to demonstrate the main stages of a complex examination and differential diagnosis of atypical facial pain on the example of a case from clinical practice. In modern conditions, the diagnosis and effective treatment of pain in the maxillofacial area is based on a multidisciplinary approach. Often, the causes of pain in the face, jaws and tongue are different. The variety of causes, complex and multi-component diagnostic protocols (and as a result, a high risk of diagnostic mistakes) – all that requires deep knowledge of the anatomy, physiology and pathophysiology of the maxillofacial area, without which it is impossible to understand the diagnosis of the above-mentioned diseases. Based on the subjective characteristics of the pain syndrome and neurological symptoms, it is not always possible to reliably establish the etiology of facial pain. It is quite risky to draw final diagnostic conclusions even with relatively high efficiency of prescribed medicine therapy, since the syndromological approach to the treatment of such patients widely used in practice is palliative in nature and does not contain requirements for a clear assessment of the etiological factor. In the case of persistent facial pain, it is important to perform special studies to verify and evaluate the structural changes involved in the process of changing anatomical formations. The presence of objective symptoms is an important criterion in the topical diagnosis of facial prosopalgia. A clinical case of prosopalgia in a 35-year-old female patient with symptoms of trigeminal neuralgia is presented. The patient marked the positive effects from the use of non-steroidal anti-inflammatory drugs (nimesulide and ibuprofen) and antiseizure medications (carbamazepine). A thorough examination of the patient's dental status made it possible to verify the diagnosis – follicular cyst of the left upper jaw from the retained and dislocated 28th tooth, orofacial pain associated with diseases of dento-alveolar and accompanying structures. The surgical treatment made it possible to successfully cure the patient. Differential diagnosis of pain in the maxillofacial area is a difficult task for both dentists and neurologists. Usually, such patients do not apply immediately after the problem arises but after some time, so additional signs of sensory, motor and trophic disorders may be detected in their status. There are often cases when the same etiological factor may cause different clinical symptoms, on the other side, a similar clinical complex is able to develop under the influence of different causes. Keywords: orofacial pain, dento-alveolar disorders, dentistry, differential diagnosis, follicular cyst.

Various Presentations Associated with Enhancement of the V2 Branch of the Trigeminal Nerve

The two patients discussed in this case report presented with radiologic enhancement of the V2 segment of the trigeminal nerve. The first patient discussed in this case report is a 78-year-old female with a history of squamous cell carcinoma of the face who presented with paresthesias involving the left V2 segment of the trigeminal nerve. A maxillofacial MRI was performed that showed subtle, thin enhancement along the outer margin of the left maxilla, and enhancement along the anterior course of V2. These findings suggested the possibility of V2 perineural spread of a tumor secondary to squamous eccrine duct carcinoma. The second case discusses a 71-year-old female who presented with symptoms of trigeminal neuralgia. An MRI was performed and showed thickening and enhancement of the right infraorbital nerve within the maxillary sinus with no significant neurovascular contact at the root entry zone. Further assessment by neurosurgery suggested this patient likely had isolated neuritis of the right infraorbital nerve, causing severe classic neuralgic symptoms. The third case presents a 28 year old male with MRI findings showing bilateral V2 enhancement within the anterior maxillary infraorbital foramina bilaterally. These three cases emphasize the importance of understanding the anatomy of the trigeminal nerve and maintaining a comprehensive knowledge of the common pathologies that affect cranial nerves. This awareness is critical in appropriately recognizing and diagnosing V2 pathologies and identifying their unique characteristics on various imaging modalities.

Digital screening method using social media advertising for the remote assessment of trigeminal neuralgia.

Global trends, such as improving accessibility to healthcare services through the Internet, and the COVID-19 pandemic are among the driving factors in the adoption of digital health. This study hypothesized that digital solutions can reach and gather data from a large number of patients with trigeminal neuralgia (TN), a commonly misdiagnosed neuropathic facial pain syndrome, and quickly and fast-track their diagnosis by suggesting them to consult a neurologist. We developed an accessible digital screening tool based on patient symptoms and history to test this hypothesis and used social media advertisement to screen a general population for TN. The standard diagnostic criteria, International Classification of Orofacial Pain, for facial pain is digitized as a web-based questionnaire that allows easy access to the evaluation for patients with suspected TN symptoms. Targeted search with relevant keywords and display campaigns on Google search engine and Facebook social media platform were used to reach large numbers of subjects. A report was autogenerated, which included a summary of a subject's symptoms, likely or likely not TN diagnosis, and information to seek appropriate medical assistance. The website was live for seven weeks and generated 240 screening questionnaire submissions, with a total spending of $2482. Forty-four subjects (18.3%) that reported typical symptoms of TN experienced unilateral and episodic pain in one of the trigeminal nerve regions. We have demonstrated the feasibility of social media advertisement and digitally screening a general population for TN, gathering valuable clinical data, such as pain characteristics, through a web-based questionnaire. Based on these data, patients with similar symptoms of TN are suggested to consult a neurologist for diagnosis. This study provides a framework for using digital screening tools to improve the healthcare experience of patients who would spend several months before finding appropriate diagnosis for their specific conditions.

The Influence of Radiologist Practice Setting on Identification of Vascular Compression from Magnetic Resonance Imaging in Trigeminal Neuralgia

Preoperative magnetic resonance imaging (MRI) studies are routinely ordered for trigeminal neuralgia (TN), though with contested reliability in contemporary literature. A potential reason for this disagreement is inconsistency in MRI reading methodologies. Here, we compare the rate of reported neurovascular compression on preoperative MRI by radiologists employed in community or private practice settings and academic neuroradiologists. A retrospective review was conducted on patients who underwent endoscopic microvascular decompression for TN with intraoperatively visualized neurovascular compression and primary read by a non-academic or community radiologist. Patient imaging was then re-read by a board-certified neuroradiologist practicing in an academic setting, who was blinded to the initial read and the side of TN symptoms. Non-academic radiologists reported vascular compression in 26.0% (20/77) of all patients, and mention was rarely made of the non-pathological side (sensitivity= 26.0%). On academic neuroradiologist re-reads, vascular compression was noted in 87.0% (67/77) of patients on the pathological side and in 57.1% (44/77) on the non-pathological side (sensitivity= 87.0%, specificity= 42.9%). Isotropic/near isotropic 3-dimensional steady state or heavily T2-weighted sequences were read with 92.3% sensitivity and 36.9% specificity, compared to 58.3% sensitivity and 66.7% specificity using routine T2 weighted sequences. The frequency of vascular compression reported by non-academic radiologists is much lower than what is reported by academic neuroradiologists reading the same MRI scans. These results highlight the effect of practice setting on the predictive power of neuroimaging. Future studies are indicated to further investigate these relationships, as well as to trial newer imaging modalities.

Ultrasound-guided dry needling of masticatory muscles in trigeminal neuralgia - A case series of 35 patients.

Trigeminal neuralgia (TGN) is considered a sensory neuropathy. However, reports of pain on chewing/speaking suggest a masticatory myofascial involvement. To examine the effect of ultrasound-guided dry needling (USGDN), which deactivates myofascial trigger points in masticatory, neck, and facial muscles on TGN symptoms. Charts of 35 patients treated for TGN were retrospectively reviewed. Treatment was USGDN alone or combined with trigeminal ganglion/mandibular nerve pulsed radiofrequency (PRF), followed by yoga mudras to stretch masticatory and facial muscles. Patients were followed for 1-8 years. Outcome parameters were reduction of medications with reduction in neuralgic attack frequency and Numeric Rating Scale (NRS) score. 23 patients (65.7%) received USGDN alone, 12 patients (34.3%) received PRF treatment before USGDN. A significant reduction in the mean (SD) NRS (5.7 [1.2] vs 8.8 [1.6]; P < .001) and neuralgic attack frequency (47 [27] vs 118 [70] attacks/day; P < .001) was seen after PRF compared with baseline, respectively. Following USGDN, the mean (SD) NRS further decreased significantly to 1.0 (0.9) (P < .001). USGDN alone produced a similar improvement in the NRS (8.9 [1.5] at baseline reduced to 0.6 [0.7] post-USGDN; P < .001). Patients in both groups reported a cessation in neuralgic attacks after USGDN. Post-USGDN, 18/27 patients completely discontinued medication, with the mean (SD) carbamazepine dose significantly reducing from 716.7 (260.9) mg/day at baseline to 113.0 (250.2) mg/day post-USGDN (P < .001). Decisive relief of TGN by USGDN suggests neuromyalgia involving masticatory muscles. Prospective, controlled studies could confirm these findings.

Correlation study between multiplanar reconstruction trigeminal nerve angulation and trigeminal neuralgia

ObjectivesNeurovascular compression (NVC) produces morphological changes on the trigeminal nerve root is considered the cause of trigeminal neuralgia (TN), but there were some patients with TN found no NVC, and also NVC was found in asymptomatic individuals. Many studies found tight relationships of TN and morphological structures of trigeminal nerve. We designed this study to explore the correlation between multiplanar reconstruction (MPR) trigeminal nerve angulation (TNA) and TN.MethodsPatients with classical symptoms of TN were recruited as observation group (OG) in this study, 50 healthy controls were enrolled as control group (CG), the OG was further subtyped into young patients (YP), middle-aged patients (MP) and old patients (OP) based to the onset age of symptoms, and also divided into patients with or without trigger maneuvers (TM) based on the presence of TM or not. All the participants underwent magnetic resonance (MR) examinations in same device, bilateral TNA measurements were carried out in OG and CG, then TNA was compared between different groups or subgroups. All images were interpreted by two radiologists who were blinded to the study, diagnosis of TN was made by two senior neurosurgery professors.ResultUltimately, 95 patients with primary TN were recruited in OG, aged from 25 to 84 (61.15 ± 12.70) years with a course of 0.5 to 30 (5.03 ± 5.41) years, their onset age ranged from 24 to 82 (56.13 ± 11.98) years. There were 34 males and 61 females in OG, and 58 cases involved right side. The CG aged from 22 to 85 (61.86 ± 13.03) years. No statistical difference was found between the age of OG and CG(p = 0.76), and also the bilateral TNA of CG (154.92 ± 16.90° vs 155.55 ± 17.03°, p > 0.05), while TNA of OG was significantly smaller than CG (150.78 ± 11.29° vs 155.24 ± 16.88°, p = 0.019). In OG, TNA on the affected side was significantly smaller than the unaffected side (149.29 ± 12.44° vs 152.27 ± 9.85°, p = 0.014). TNA showed a positive correlation with onset age of patients with TN, as TNA on the affected side of YP was significantly smaller than MP and OP (139.00 ± 11.64° vs 148.86 ± 11.54°, 139.00 ± 11.64° vs 152.18 ± 12.61°, p = 0.004 and 0.026). Furthermore, patients with TM showed smaller TNA than those without TM (147.05 ± 11.30° vs 164.75 ± 8.39°, p < 0.001).ConclusionsThis study suggested that TNA might play a role in TN, small TNA could be a risk factor of TN. Furthermore, patients with small TNA are more likely to combine with TM, but more studies are needed to explore the exact role of TNA in TN.

Pain Mimicking Trigeminal Neuralgia in Patients with Acute Ischemic Stroke of the Brainstem

Background and PurposeCases of pain mimicking trigeminal neuralgia (TN) induced by ischemic stroke in the brainstem have been sparsely reported. The study was to determine the characteristics of symptomatic TN in patients with acute ischemic stroke in the medulla oblongata and pons, and to determine the location of the ischemic lesion associated with the pain.Patients and MethodsA total of 6/21 (28.5%) patients with medullary ischemic stroke and 3/34 (8.8%) patients with pontine ischemic stroke who experienced pain mimicking TN between 1 week before and 2 weeks after the stroke onset were enrolled in the study. All patients accepted neuroimaging examinations to determine the location of the ischemic lesion and the etiology of ischemic stroke. The characteristics of pain were recorded and analyzed.ResultsIschemic lesions of patients who experienced pain mimicking TN were located in the lateral medulla oblongata (n=6), nerve root entry zoo (n=2), and areas involved with the spinal trigeminal tract (n=1) in the pons. Half of the instances of pain induced by medullary ischemic stroke occurred prior to the stroke onset. The branch of V1 was exclusively involved in patients with lateral medullary infarction and the branches of V2 and V3 were typically involved in patients with pontine infarction. The pain was relieved spontaneously (n=4, 44.4%) or was controlled with drugs for neuropathic pain treatment (n=5, 55.5%).ConclusionHalf of the instances of pain induced by medullary ischemic stroke occurred prior to the stroke onset. Pain mimicking TN might be a premonitory symptom of the medullary ischemic stroke. Pain mimicking TN induced by brainstem infarction has a good prognosis.

BmK DKK13, A Scorpion Toxin, Alleviates Pain Behavior in a Rat Model of Trigeminal Neuralgia by Modulating Voltage-Gated Sodium Channels and MAPKs/CREB Pathway.

BmK DKK13 (DKK13) is a mutated recombinant peptide, which has a significant antinociception in a rat model of the inflammatory pain. The purpose of this study was to evaluate the antinociceptive effect of DKK13 on trigeminal neuralgia (TN) in rats. Male Sprague-Dawley (SD) rats were treated with the chronic constriction injury of the infraorbital nerve (IoN-CCI) model to induce stable symptoms of TN. DKK13 (1.0 mg/kg, 2.0 mg/kg and 4.0 mg/kg, i.v.) or morphine (4.0 mg/kg, i.v.) was administered by tail vein once on day 14 after IoN-CCI injury. Behavioral tests, electrophysiology and western blotting were performed to investigate the role and underlying mechanisms of DKK13 on IoN-CCI model. Behavioral test results showed that DKK13 could significantly increase the mechanical pain and thermal radiation pain thresholds of IoN-CCI rats and inhibit the asymmetric spontaneous pain scratching behavior. Electrophysiological results showed that DKK13 could significantly reduce the current density of Nav1.8 in the ipsilateral side of trigeminal ganglion (TG) neurons in IoN-CCI rats, and the steady-state activation and inactivation curves of Nav1.8 shifted, respectively, to the direction of hyperpolarization and depolarization. Western blotting results showed that DKK13 significantly reduced the expression of Nav1.8 and the phosphorylation levels of key proteins of MAPKs/CREB pathway in TG tissues of IoN-CCI rats. In brief, DKK13 has a significant antinociceptive effect on IoN-CCI rats, which may be achieved by changing the dynamic characteristics of Nav1.8 channel and regulating the protein phosphorylation in MAPKs/CREB pathway.

A study to evaluate neurovascular conflict of trigeminal nerve in trigeminal neuralgia patients with the help of 1.5\xa0T MR imaging

IntroductionTrigeminal neuralgia is a neuropathic pain that occurs in the sensory supply region of the trigeminal nerve (V cranial nerve). The common etiology of trigeminal neuralgia is said to be vascular compression on the trigeminal nerve root. In our day-to-day practice, we see many asymptomatic patients having vascular loops around the trigeminal nerve root. We undertook this study to see the significance of nerve root compression by the vascular loop as a cause for trigeminal neuralgia.Materials and methodsA total of 67 classical trigeminal neuralgia patients with NVC involving the trigeminal nerve as diagnosed on MRI brain sequences including FIESTA sequence were included in the study. NVC in all the patients were studied for the side, site of neurovascular contact of cisternal segment of the trigeminal nerve from the brainstem, deviation of nerve at NVC, atrophy of nerve, nature and origin of vascular loop causing NVC and correlated with TGN symptoms.ResultsOut of 67 patients studied, all of them (100%) had NVC on ipsilateral side and 26 patients (34%) had NVC at contralateral trigeminal nerve. Incidence of trigeminal neuralgia was most commonly seen between the 41 and 60 years age (64%) followed by 61–80 years with mean age of 55.6 years. Incidence in females (64%) was found to be more common than in males (35%). NVC was observed at the root entry zone (< 7 mm from brain stem) in 63 trigeminal nerves on symptomatic side and 5 trigeminal nerves on the asymptomatic side. NVC occurring at REZ on symptomatic side was found to be statistically significant with P < 0.001. Mean distance of NVC from brain stem at symptomatic side was 3.4 mm and was 8.4 mm in asymptomatic side NVCs. Atrophy was seen in 8 trigeminal nerves, all on symptomatic side and NVC occurring at root entry zone. No displacement of nerve root at the point of neurovascular contact was observed in our study. Most common vessel causing was found to be ipsilateral superior cerebellar artery followed by the ipsilateral anterior inferior cerebellar artery.ConclusionsNeurovascular contact of trigeminal nerve occurring at the nerve root entry zone has a strong association with ipsilateral trigeminal neuralgia symptoms. In addition, the presence of the trigeminal nerve thinning is also associated with ipsilateral trigeminal neuralgia. With the increase in age, there are higher chances of association of NVC with ipsilateral trigeminal neuralgia symptoms.