root entry zone
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2022 ◽  
Vol 12 ◽  
Author(s):  
Jacob C. A. Edvinsson ◽  
Kristian A. Haanes ◽  
Lars Edvinsson

The trigeminovascular system (TGV) comprise of the trigeminal ganglion with neurons and satellite glial cells, with sensory unmyelinated C-fibers and myelinated Aδ-fibers picking up information from different parts of the head and sending signals to the brainstem and the central nervous system. In this review we discuss aspects of signaling at the distal parts of the sensory fibers, the extrasynaptic signaling between C-fibers and Aδ-fibers, and the contact between the trigeminal fibers at the nerve root entry zone where they transit into the CNS. We also address the possible role of the neuropeptides calcitonin gene-related peptide (CGRP), the neurokinin family and pituitary adenylyl cyclase-activating polypeptide 38 (PACAP-38), all found in the TGV system together with their respective receptors. Elucidation of the expression and localization of neuropeptides and their receptors in the TGV system may provide novel ways to understand their roles in migraine pathophysiology and suggest novel ways for treatment of migraine patients.


2021 ◽  
Vol 15 ◽  
Author(s):  
Jinghui Lin ◽  
Lei Mou ◽  
Qifeng Yan ◽  
Shaodong Ma ◽  
Xingyu Yue ◽  
...  

Trigeminal neuralgia caused by paroxysmal and severe pain in the distribution of the trigeminal nerve is a rare chronic pain disorder. It is generally accepted that compression of the trigeminal root entry zone by vascular structures is the major cause of primary trigeminal neuralgia, and vascular decompression is the prior choice in neurosurgical treatment. Therefore, accurate preoperative modeling/segmentation/visualization of trigeminal nerve and its surrounding cerebrovascular is important to surgical planning. In this paper, we propose an automated method to segment trigeminal nerve and its surrounding cerebrovascular in the root entry zone, and to further reconstruct and visual these anatomical structures in three-dimensional (3D) Magnetic Resonance Angiography (MRA). The proposed method contains a two-stage neural network. Firstly, a preliminary confidence map of different anatomical structures is produced by a coarse segmentation stage. Secondly, a refinement segmentation stage is proposed to refine and optimize the coarse segmentation map. To model the spatial and morphological relationship between trigeminal nerve and cerebrovascular structures, the proposed network detects the trigeminal nerve, cerebrovasculature, and brainstem simultaneously. The method has been evaluated on a dataset including 50 MRA volumes, and the experimental results show the state-of-the-art performance of the proposed method with an average Dice similarity coefficient, Hausdorff distance, and average surface distance error of 0.8645, 0.2414, and 0.4296 on multi-tissue segmentation, respectively.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junjin Lin ◽  
Luxi Zhou ◽  
Zhaoke Luo ◽  
Madeha Ishag Adam ◽  
Li Zhao ◽  
...  

AbstractMicrovascular compression of the trigeminal root entry zone (TREZ) is the main cause of most primary trigeminal neuralgia (TN), change of glial plasticity was previously studied in the TREZ of TN rat model induced by chronic compression. To better understand the role of astrocytes and immune cells in the TREZ, different cell markers including glial fibrillary acidic protein (GFAP), complement C3, S100A10, CD45, CD11b, glutamate-aspartate transporter (GLAST), Iba-1 and TMEM119 were used in the TN rat model by immunohistochemistry and flow cytometry. On the post operation day 28, GFAP/C3-positive A1 astrocytes and GFAP/S100A10-positive A2 astrocytes were activated in the TREZ after compression injury, there were no statistical differences in the ratios of A1/A2 astrocytes between the sham and TN groups. There was no significant difference in Iba-1-positive cells between the two groups. The ratios of infiltrating lymphocytes (CD45+CD11b−) (p = 0.0075) and infiltrating macrophages (CD45highCD11b+) (p = 0.0388) were significantly higher than those of the sham group. In conclusion, different subtypes A1/A2 astrocytes in the TREZ were activated after compression injury, infiltrating macrophages and lymphocytes increased, these neuroimmune cells in the TREZ may participate in the pathogenesis of TN rat model.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Tai-Yuan Chen ◽  
Ching-Chung Ko ◽  
Te-Chang Wu ◽  
Li-Ching Lin ◽  
Yun-Ju Shih ◽  
...  

Abstract Background Trigeminal neuralgia (TN) is the most common type of chronic neuropathic facial pain, but the etiology and pathophysiological mechanisms after treatment are still not well understood. The purpose of this study was to investigate the longitudinal changes of the cisternal segment of the trigeminal nerve and brain pain-related regions in patients with TN before and after treatment using readout segmentation of long variable echo-train (RESOLVE) diffusion tensor imaging (DTI) and transverse relaxation (T2)-weighted sampling perfection with application-optimized contrast at different flip angle evolutions (T2-SPACE). Methods Twelve patients with TN and four healthy controls were enrolled in this study. All patients underwent assessment of the visual analog scale (VAS), and acquisition of RESOLVE DTI and T2-SPACE images before and at 1, 6, and 12 months after treatments. Regions-of-interest were placed on the bilateral anterior, middle, and posterior parts of the cisternal segment of the trigeminal nerve, the bilateral root entry zone (REZ), bilateral nuclear zone, and the center of pontocerebellar tracts, respectively. Voxel-based morphometry (VBM) analysis was conducted with T2-SPACE images, and gray matter volumes (GMV) were measured from brain pain-matrix regions. Results The results demonstrated that the VAS scores, the axial diffusivity of the middle part of the affected cisternal trigeminal nerve, the fractional anisotropy of the bilateral nuclear zones, and the mean diffusivity of the center of pontocerebellar tract significantly changed over time before and after treatment. The changes of GMV in the pain-matrix regions exhibited similar trends to the VAS before and after treatment. Conclusion We conclude that magnetic resonance imaging with RESOLVE DTI and VBM with T2-SPACE images were helpful in the understanding of the pathophysiological mechanisms in patients with TN before and after treatment.


2021 ◽  
pp. 1-8

OBJECTIVE The authors aimed to investigate predictors of postoperative outcomes of microvascular decompression (MVD) for the treatment of glossopharyngeal neuralgia (GPN). METHODS A cohort of 97 patients with medically refractory GPN who underwent MVD at the authors’ institution between January 2010 and July 2019 was retrospectively reviewed. Univariate and multivariate regression models were used to identify predictors of long-term outcome in patients after MVD. RESULTS Eighty-nine patients (91.8%) reported immediate and complete relief of pain after the procedure. Of the remaining 8 patients (8.2%), 6 achieved partial pain relief and pain gradually diminished within 2 weeks after surgery, and 2 did not experience postoperative pain relief. In univariate Cox regression analysis, venous compression of the glossopharyngeal nerve root entry zone (HR 3.591, 95% CI 1.660–7.767, p = 0.001) and lower degree of neurovascular conflict (HR 2.449, 95% CI 1.177–5.096, p = 0.017) were significantly associated with worse pain-free survival. In multivariate Cox regression analysis, venous compression (HR 8.192, 95% CI 2.960–22.669, p < 0.001) and lower degree of neurovascular conflict (HR 5.450, 95% CI 2.069–14.356, p = 0.001) remained independently associated with worse pain-free survival. CONCLUSIONS Venous compression of the glossopharyngeal nerve root entry zone and lower degree of neurovascular conflict were significantly correlated with shorter pain-free survival in patients who underwent MVD for GPN. Microvascular decompression is a safe, feasible, and durable approach with a low complication rate for the treatment of GPN.


2021 ◽  
Vol 2 ◽  
Author(s):  
Alan Chalil ◽  
Qian Wang ◽  
Mohamad Abbass ◽  
Brendan G. Santyr ◽  
Keith W. MacDougall ◽  
...  

Introduction: Brachial plexus avulsion (BPA) injuries commonly occur secondary to motor vehicle collisions, usually in the young adult population. These injuries are associated with significant morbidity, and up to 90% of patients suffer from deafferentation pain. Neuromodulation procedures can be efficacious in the treatment of refractory neuropathic pain, although the treatment of pain due to BPA can be challenging. Dorsal root entry zone (DREZ) lesioning is a classical and effective neurosurgical technique which has become underutilized in treating refractory root avulsion pain.Methods: A systematic review of the different technical nuances, procedural efficacy, and complication profiles regarding DREZ lesioning for BPA injuries in the literature is included. We also present an institutional case series of 7 patients with BPA injuries who underwent DREZ lesioning.Results: In the literature, 692 patients were identified to have undergone DREZ lesioning for pain related to BPA. In 567 patients, the surgery was successful in reducing pain intensity by over 50% in comparison to baseline (81.9%). Complications included transient motor deficits (11%) and transient sensory deficits (11%). Other complications including permanent disability, cardiovascular complications, infections, or death were rare (&lt;1.9%). In our case series, all but one patient achieved &gt;50% reduction in pain intensity, with the mean pre-operative pain of 7.9 ± 0.63 (visual analog scale) reduced to 2.1 ± 0.99 at last follow-up (p &lt; 0.01).Conclusion: Both the literature and the current case series demonstrate excellent pain severity reduction following DREZ ablation for deafferentation pain secondary to BPA.


Author(s):  
Yun-fei Xia ◽  
Wei-ping Zhou ◽  
Ying Zhang ◽  
Yan-zhen Li ◽  
Xu-hui Wang ◽  
...  

Abstract Background Microvascular decompression (MVD) has become accepted as an effective therapeutic option for hemifacial spasm (HFS); however, the curative rate of MVD for HFS varies widely (50–98%) in different medical centers. This study could contribute to the improvement of the MVD procedure. Methods We retrospectively analyzed 32 patients in whom initial MVD failed in other hospitals and who underwent a second MVD at our center. The clinical characteristics, operative findings, outcome of the second MVD, and complications were recorded. Results There were 18 women and 14 men (56.3 and 43.7%, respectively). The left-to-right ratio was 19:13. The mean age of the patients was 59.8 years. We found an undiscovered conflict site located in zone 4 in 10 patients and in the root entry zone in 8 patients. The initial MVD failed in nine patients because of ignorance of the arterioles that originate from the anterior inferior cerebellar artery. There were no special findings in four patients. No Teflon felts were found in the whole surgical field in one patient. Conclusion Omission of the offending vessel is the most common cause of an unsuccessful MVD. Intraoperative abnormal muscle response associated with the Z-L response is a good measure to correctly identify the involved arterioles.


2021 ◽  
Vol 5 (2) ◽  
pp. V10
Author(s):  
Kunal Vakharia ◽  
Anthony L. Mikula ◽  
Ashley M. Nassiri ◽  
Colin L. W. Driscoll ◽  
Michael J. Link

A patient with trigeminal neuralgia secondary to a vestibular schwannoma underwent fractionated radiotherapy without relief of her pain. She was then effectively treated with microsurgical resection of her tumor. Early identification of the lower cranial nerves and the origin of the facial and vestibulocochlear nerves is key to determining the operative corridors for vestibular schwannoma resection. To effectively treat trigeminal neuralgia, the trigeminal nerve root entry zone and motor branch are clearly identified and decompressed. Fractioned radiotherapy does not effectively treat trigeminal neuralgia secondary to vestibular schwannoma compression. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID21112


2021 ◽  
pp. 5-11
Author(s):  
Victor Souza ◽  
Maria Passerini ◽  
Bianca Sobral ◽  
Vinicius Baiardi ◽  
Hilton Junior

Introduction Glossopharyngeal neuralgia is a rare syndrome characterized by paroxysms of unilateral and severe stabbing pain occurring in the nerve’s distribution. Although other neuralgias are well described in the medical literature, glossopharyngeal neuralgia and its physiopathology are not. The vascular compression at the nerve root entry zone is the primary explanation for the disease. The first-line treatment is pharmacological, including carbamazepine, oxcarbazepine, and gabapentin. Surgical treatment is offered to medication-refractory patients, and microvascular decompression surgery has the best outcomes. Objective To investigate the pathophysiological and clinical aspects of the different presentations of glossopharyngeal neuralgia. Method: A systematic review of the literature including case reports and clinical trials, was done. Results A search of the literature yielded 31 papers that regarded glossopharyngeal neuralgia or its variants. Eight of these reports regarded vagoglossopharyngeal neuralgia. Seven regarded the glossopharyngeal neuralgia followed by or caused by another disease. Conclusion Glossopharyngeal neuralgia is a rare disease and requires further studies on its mechanism and clinical assessment; the physician needs to know how to distinguish it from its variants and underlying causes.


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