[Left mandibular osteonecrosis following herpes zoster of the third branch of left trigeminal nerve: A case report].

Herpes zoster of trigeminal nerve was a common skin disease caused by varicella-zoster virus infection. Simple involvement of the third branch of trigeminal nerve was rare, and so were oral complications such as pulpitis, periodontitis, spontaneous tooth loss, bone necrosis, etc. This article presented a case of herpes zoster on the third branch of the left trigeminal nerve complicated with left mandibular osteonecrosis. We reported the case of a 64-year-old man with sudden pain in the left half of the tongue 1 month ago, and then herpes on the left facial skin appeared following with acute pain.The local hospital diagnosed it as herpes zoster and treated it with external medication. A few days later, he developed gum pain in the left mandibular posterior tooth area. He was admitted to Peking University School and Hospital of Stomatology one week ago with loose and dislodged left posterior tooth accompanied by left mandibular bone surface exposure. Clinical examination showed bilateral symmetry and no obvious restriction of mouth opening. Visible herpes zoster pigmentation and scarring on the left side of the face appeared. The left mandibular posterior tooth was missing, the exposed bone surface was about 1.5 cm×0.8 cm, and the surrounding gingiva was red and swollen, painful under pressure, with no discharge of pus. The remaining teeth in the mouth were all Ⅲ degree loosened. Imageological examination showed irregular low-density destruction of the left mandible bone, unclear boundary, and severe resorption of alveolar bone. The patient was diagnosed as left mandibular osteonecrosis. Under general anesthesia, left mandibular lesion exploration and curettage + left mandibular partial resection + adjacent flap transfer repair were performed. The patient was re-exmained 6 months after surgery, there was no redness, swelling or other abnormality in the gums and the herpes pigmentation on the left face was significantly reduced. Unfortunately, the patient had complications of postherpetic neuralgia. This case indicate that clinicians should improve their awareness of jaw necrosis, a serious oral complication of trigeminal zoster, and provide early treatment. After the inflammation was initially controlled, surgical treatment could be considered to remove the necrotic bone, curettage the inflammatory granulation tissue, and extraction of the focal teeth to avoid further deterioration of the disease.

Herpes zoster of posterior division of mandibular branch of trigeminal nerve.

Herpes zoster is a disease caused by the reactivation of dormant varicella zoster virus present in the sensory root ganglion. It presents with a vesicular rash on an erythematous base similar to that seen in classical varicella, however, with only a single dermatomal distribution. The rash is usually seen throughout the affected dermatome as the dorsal root ganglia for each dermatome are clustered together. We present a case of an otherwise healthy male who developed a vesicular rash confined to the distribution of the posterior division of the mandibular nerve. Though the entire mandibular nerve arises from a single ganglion, the skin area supplied by the anterior division of the mandibular nerve was spared. This case provides evidence to show that there is anatomic segregation of cell bodies of nerves traversing anterior and posterior divisions of mandibular division in the trigeminal ganglion and that partial involvement of a sensory root ganglion is possible in immunocompetent patients.

Chronic Constriction Injury of the Distal Infraorbital Nerve (DIoN-CCI) in Mice to Study Trigeminal Neuropathic Pain.

Animal models remain necessary tools to study neuropathic pain. This manuscript describes the distal infraorbital nerve chronic constriction injury (DIoN-CCI) model to study trigeminal neuropathic pain in mice. This includes the surgical procedures to perform the chronic constriction injury and the postoperative behavioral tests to evaluate the changes in spontaneous and evoked behavior that are signs of ongoing pain and mechanical allodynia. The methods and behavioral readouts are similar to the infraorbital nerve chronic constriction injury (IoN-CCI) model in rats. However, important changes are necessary for the adaptation of the IoN-CCI model to mice. First, the intra-orbital approach is replaced by a more rostral approach with an incision between the eye and the whisker pad. The IoN is thus ligated distally outside the orbital cavity. Secondly, due to the higher locomotor activity in mice, allowing rats to move freely in small cages is replaced by placing mice in custom-designed and constructed restraining devices. After DIoN ligation, mice exhibit changes in spontaneous behavior and in response to von Frey hair stimulation that are similar to those in IoN-CCI rats, i.e., increased directed face grooming and hyperresponsiveness to von Frey hair stimulation of the IoN territory.

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.

BACKGROUND: Idiopathic 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. METHODS: Eighteen 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. RESULTS: Mechanical 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. CONCLUSION: Ipsilateral 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.

Extracranial transport of brain lymphatics via cranial nerve in human.

Extracranial waste transport from the brain interstitial fluid to the deep cervical lymph node (dCLN) is not extensively understood. The present study aims to show the cranial nerves that have a role in the transport of brain lymphatics vessels (LVs), their localization, diameter, and number using podoplanin (PDPN) and CD31 immunohistochemistry (IHC) and Western blotting. Cranial nerve samples from 6 human cases (3 cadavers, and 3 autopsies) were evaluated for IHC and 3 autopsies for Western blotting. The IHC staining showed LVs along the optic, olfactory, oculomotor, trigeminal, facial, glossopharyngeal, accessory, and vagus nerves. However, no LVs present along the trochlear, abducens, vestibulocochlear, and hypoglossal nerves. The LVs were predominantly localized at the endoneurium of the cranial nerve that has motor components, and LVs in the cranial nerves that had sensory components were present in all 3 layers. The number of LVs accompanying the olfactory, optic, and trigeminal nerves was classified as numerous; oculomotor, glossopharyngeal, vagus, and accessory was moderate; and facial nerves was few. The largest diameter of LVs was in the epineurium and the smallest one was in the endoneurium. The majority of Western blotting results correlated with the IHC. The present findings suggest that specific cranial nerves with variable quantities provide a pathway for the transport of wastes from the brain to dCLN. Thus, the knowledge of the transport of brain lymphatics along cranial nerves may help understand the pathophysiology of various neurological diseases.

Neuralgia in the occipital region associated with ipsilateral trigeminal herpes zoster: Three case reports.

BACKGROUND: Nerve fibers related to pain and temperature sensation in the trigeminal nerve territory converge with the upper cervical spinal nerves from the level of the lower medulla oblongata to the upper cervical cord. This structure is called the trigemino-cervical complex and may cause referred pain in the territory of the trigeminal or upper cervical spinal nerves. CASE SERIES: Here, we report three cases of paroxysmal neuralgia in the occipital region with mild conjunctivitis or a few reddish spots in the ipsilateral trigeminal nerve territory. The patients exhibited gradual progression of these reddish spots evolving into vesicles over the course of several days, despite the absence of a rash in the occipital region. The patients were diagnosed with trigeminal herpes zoster and subsequently received antiherpetic therapy. Remarkably, the neuralgia in the occipital region showed gradual amelioration or complete resolution before the treatment, with no sequelae reported in the occipital region. DISCUSSION: The trigemino-cervical complex has the potential to cause neuralgia in the occipital region, as referred pain, caused by trigeminal herpes zoster. These cases suggest that, even if conjunctivitis or reddish spots appear to be trivial in the trigeminal nerve territory, trigeminal herpes zoster should be considered when neuralgia occurs in the ipsilateral occipital region.

Efficacy and safety of trigeminal parasympathetic pathway stimulation for dry eye: A systematic review and meta-analysis.

This study aimed to investigate the efficacy and safety of trigeminal parasympathetic pathway (TPP) stimulation in the treatment of dry eye. A comprehensive search for randomized clinical trials was performed in seven databases (MEDLINE, Embase, CENTRAL, etc.) up to 28 February 2023. After screening the suitable studies, the data were extracted and transformed as necessary. Data synthesis and analysis were performed using Review Manager 5.4, and the risk of bias and quality of evidence were evaluated with the recommended tools. Fourteen studies enrolling 1714 patients with two methods (electrical and chemical) of TPP stimulation were included. Overall findings indicate that TPP stimulation was effective in reducing subjective symptom score (standardized mean difference [SMD], -0.45; 95% confidence interval [CI], -0.63 to -0.28), corneal fluorescence staining (mean difference [MD], -0.78; 95% CI, -1.39 to -0.18), goblet cell area (MD, -32.10; 95% CI, -54.58 to -9.62) and perimeter (MD, -5.90; 95% CI, -10.27 to -1.53), and increasing Schirmer's test score (SMD, 0.98; 95% CI, 0.65 to 1.31) and tear film break-up time (SMD, 0.57; 95% CI, 0.19 to 0.95). Compared to inactive or low-activity stimulation controls, it has a higher incidence of adverse events. Therefore, TPP stimulation may be an effective treatment for dry eye, whether electrical or chemical. Adverse events are relatively mild and tolerable. Due to the high heterogeneity and low level of evidence, the current conclusions require to be further verified.

Three-dimensional topography of rat trigeminal ganglion neurons using a combination of retrograde labeling and tissue-clearing techniques.

The trigeminal nerve is the sensory afferent of the orofacial regions and divided into three major branches. Cell bodies of the trigeminal nerve lie in the trigeminal ganglion and are surrounded by satellite cells. There is a close interaction between ganglion cells via satellite cells, but the function is not fully understood. In the present study, we clarified the ganglion cells' three-dimensional (3D) localization, which is essential to understand the functions of cell-cell interactions in the trigeminal ganglion. Fast blue was injected into 12 sites of the rat orofacial regions, and ganglion cells were retrogradely labeled. The labeled trigeminal ganglia were cleared by modified 3DISCO, imaged with confocal laser-scanning microscopy, and reconstructed in 3D. Histograms of the major axes of the fast blue-positive somata revealed that the peak major axes of the cells innervating the skin/mucosa were smaller than those of cells innervating the deep structures. Ganglion cells innervating the ophthalmic, maxillary, and mandibular divisions were distributed in the anterodorsal, central, and posterolateral portions of the trigeminal ganglion, respectively, with considerable overlap in the border region. The intermingling in the distribution of ganglion cells within each division was also high, in particular, within the mandibular division. Specifically, intermingling was observed in combinations of tongue and masseter/temporal muscles, maxillary/mandibular molars and masseter/temporal muscles, and tongue and mandibular molars. Double retrograde labeling confirmed that some ganglion cells innervating these combinations were closely apposed. Our data provide essential information for understanding the function of ganglion cell-cell interactions via satellite cells.

Efficacy of MR Neurography of Peripheral Trigeminal Nerves: Correlation of Sunderland Grade versus Neurosensory Testing.

BACKGROUND AND PURPOSE: The current reference standard of diagnosis for peripheral trigeminal neuropathies (PTN) is clinical neurosensory testing (NST). MR neurography (MRN) is useful for PTN injury diagnosis, but it has only been studied in small case series. The aim of this study was to evaluate the agreement of Sunderland grades of nerve injury on MRN and NST by using surgical findings and final diagnoses as reference standards. MATERIALS AND METHODS: A total of 297 patient records with a chief complaint of PTN neuralgia were identified from the university database, and 70 patients with confirmed NST and MRN findings who underwent surgical nerve repair were included in the analysis. Cohen weighted kappa was used to calculate the strength of the agreement between the 3 modalities. RESULTS: There were 19 men and 51 women, with a mean age of 39.6 years and a standard deviation of 16.9 years. Most (51/70, 73%) injuries resulted from tooth extractions and implants. MRN injury grades agreed with surgical findings in 84.09% (37/44) of cases, and NST injury grades agreed with surgical findings in 74.19% (23/31) of cases. MRN and NST both showed similar agreement with surgery for grades I to III (70% and 71.43%). However, MRN showed a higher rate of agreement with surgery (88.24%) for injury grades IV and V than did NST (75%). CONCLUSIONS: MRN can objectively improve preoperative planning in patients with higher-grade nerve injuries.

In situ tissue profile of rat trigeminal nerve in trigeminal neuralgia using spatial transcriptome sequencing.

BACKGROUND: Trigeminal neuralgia (TN) is the most common neuropathic disorder in the maxillofacial region. The etiology and pathogenesis of TN have not been clearly determined to date, although there are many hypotheses. OBJECTIVE: The goal of this study was to investigate the interactions between different types of cells in TN, particularly the impact and intrinsic mechanism of demyelination on the trigeminal ganglion, and to identify new important target genes and regulatory pathways in TN. METHODS: TN rat models were prepared by trigeminal root compression, and trigeminal nerve tissues were isolated for spatial transcriptome sequencing. The gene expression matrix was reduced dimensionally by PCA and presented by UMAP. Gene function annotation was analyzed by Metascape. The progression of certain clusters and the developmental pseudotime were analyzed using the Monocle package. Modules of the gene coexpression network between different groups were analyzed based on weighted gene coexpression network analysis and assigned AddModuleScore values. The intercellular communication of genes in these networks via ligand-receptor interactions was analyzed using CellPhoneDB analysis. RESULTS: The results suggested that the trigeminal ganglion could affect Schwann cell demyelination and remyelination responses through many ligand-receptor interactions, while the effect of Schwann cells on the trigeminal ganglion was much weaker. Additionally, ferroptosis may be involved in the demyelination of Schwann cells. CONCLUSIONS: This study provides spatial transcriptomics sequencing data on TN, reveals new markers, and redefines the relationship between the ganglion and myelin sheath, providing a theoretical basis and supporting data for future mechanistic research and drug development.

The long-term outcome of CT-guided radiofrequency ablation of the peripheral branches of the trigeminal nerve in trigeminal neuralgia.

Radiofrequency thermocoagulation (RFTC) of the peripheral branches of the trigeminal nerve has been used for trigeminal neuralgia. However, the long-term outcomes of radiofrequency thermocoagulation have not been established. To evaluate the long-term efficacy of RFTC of peripheral branches in patients with refractory trigeminal neuralgia. A retrospective cohort study was conducted in a comprehensive medical center in China. Patients who underwent radiofrequency thermocoagulation of peripheral branches for refractory trigeminal neuralgia from May 2014 to March 2021 were included for analysis. A total of 84 patients with refractory trigeminal neuralgia underwent 105 procedures. BNI I-II which represents treatment success was achieved in 76/84 (90%) patients and 93/105 (89%) procedures. During follow-up, BNI I and II were maintained in 64/76 (84%), 40/73 (55%), 20/67 (30%), 17/65 (26%), 12/61 (20%), and 8/58 (14%) of patients at 1, 2, 3, 4, 5, and 6 years, after the first procedure, respectively. For all the 105 procedures, BNI I and II were maintained in 68/93 (73%), 41/89(46%), 22/82(27%), 15/79 (19%), 8/74 (11%), and 3/72 (4%) at 1, 2, 3, 4, 5, and 6 years, respectively. There is no significant difference between the first and repeat thermocoagulation in terms of immediate (90% vs. 81%, P=0.140) and long-term efficacies (24 months vs.18 months, P=0.266). Radiofrequency thermocoagulation resulted in better long-term outcomes in patients with typical purely paroxysmal pain (24 months vs. 11 months, P=0.033). Radiofrequency ablation of the peripheral branches of the trigeminal nerve might be a safe and effective method in the treatment of refractory trigeminal neuralgia.

Assessing the Efficacy of Allogeneic Nerve Grafts in Trigeminal Nerve Repair: A Systematic Review.

PURPOSE: Our primary objective was to assess the efficacy of allogeneic nerve grafts in inferior alveolar nerve or lingual nerve repair. We hypothesized that using allogeneic nerve grafts would be effective, as evidenced by achieving high rates of functional sensory recovery (FSR). Additionally, we looked if sex, time from injury to repair, etiology of nerve damage, and graft length affected outcomes. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted. PubMed and Scopus databases were searched using specific search strategies to generate eligible studies. Inclusion criteria encompassed studies reporting use of allogeneic grafts, assessing FSR using either Medical Research Council Scale or Neurosensory Testing, and published within the past 15 years. RESULTS: Across 10 studies conducted between 2011 and 2023, analysis was performed on 149 patients and 151 reconstructed nerves. Allogeneic nerve grafts showed an average FSR rate of 88.0%. Kaplan-Meier analysis of time to FSR postoperatively revealed that of those achieving FSR, 80% achieved it within 6 months and 98% achieved it by 1 year. The mean graft length was 29.92 mm ± 17.94 mm. The most common etiology for nerve damage was third molar extractions (23.3%). Sex distribution among patients revealed that 85 were female (57.0%) and 64 were male (43.0%). CONCLUSION: Our primary hypothesis was supported as nerve allografts achieved high rates of FSR. FSR was achieved in normative timeframes, which is 6 to 12 months postoperatively. Furthermore, allografts reduced the risk of posttraumatic trigeminal neuropathy. Time from injury to repair, graft length, etiology of nerve damage, and sex did not affect FSR. As the assessed variables in our study did not affect outcomes, there needs to be a more nuanced approach to understanding and addressing various factors influencing sensory recovery.

Complementary and Integrative Medicine for the Treatment of Trigeminal Neuralgia and Trigeminal Autonomic Cephalalgia.

PURPOSE OF REVIEW: Trigeminal neuralgia (TN) and trigeminal autonomic cephalalgias (TACs) are both painful diseases which directly impact the branches of the trigeminal nerve, which supply the face. Patients who have experienced adverse effects, have not responded to mainstream treatments, or have a personal preference for nonmedication options, often turn to complementary and integrative medicine (CIM). The aim of this review is to discuss the efficacy and safety of CIM therapies available for the treatment of TN and TACs. RECENT FINDINGS: Not only are there limited therapeutic options for TN and TAC patients, but also is there a proportion of patients who are intolerant to standard medical treatments. Recent findings have illustrated that 86% of patients with headache disorders utilize CIM modalities in combination with mainstream medical therapy. CIM modalities can be helpful for these diseases and have primarily been studied in combination with standard medical therapy. There is limited evidence for CIM and behavioral therapies in managing these conditions, and more research is needed to confirm which therapies are safe and effective.

A Predictive Model for the Risk of Postsurgery Pain Recurrence in the V1 Branch of the Trigeminal Nerve.

BACKGROUND: The factors influencing pain recurrence following V1 trigeminal nerve surgery are still unknown. OBJECTIVE: We aimed to analyze the risk factors affecting pain recurrence following surgery in the V1 branch of the trigeminal nerve, construct a nomogram-based therapeutic efficacy prediction model using logistic regression analysis, and validate the model's predictive performance. STUDY DESIGN: A retrospective study. SETTING: This study was performed at the Affiliated Hospital of Jiaxing University, People's Republic of China. METHODS: Data were retrospectively collected from 131 patients with trigeminal neuralgia and V1 branch algesia who underwent either radiofrequency thermocoagulation through the supraorbital foramen or percutaneous balloon compression at the Pain Department of the Affiliated Hospital of Jiaxing University from March 2017 through January 2021. The patients were randomly divided into a training group (n = 92) and a testing group (n = 39) in a 7:3 ratio. A least absolute shrinkage and selection operator (LASSO) regression was used to screen independent predictive factors. The outcome variable was whether the patient experienced pain recurrence within 2 years postsurgery. Those results were used to construct a nomogram-based predictive model, followed by a multivariate logistic regression analysis. The feasibility of the nomogram-based predictive model was evaluated by the validation group. Finally, the predictive model's discrimination ability, accuracy, and clinical usability were evaluated using a receiver operating characteristic curve, calibration curves, and decision curve analysis, respectively. RESULTS: The results indicate that among the total 131 patients, 76 patients did not experience pain recurrence within 2 years postsurgery, while 55 patients suffered a pain recurrence. The results of the LASSO regression, combined with a multivariate logistic regression analysis, showed that age, pre-Numeric Rating Scale score, and surgery type were the influencing factors for patients with V1 branch pain who experienced pain recurrence within 2 years postsurgery (P < 0.05). From this data a nomogram-based predictive model was established. The area under the curve of the nomogram-based predictive model for the training group was found to be 0.890 (95% CI, 0.818 - 0.961); in the test group it was 0.857 (95% CI, 0.748 - 0.965) in the test group. The Hosmer-Lemeshow goodness-of-fit test revealed an excellent fit (P > 0.05), while the decision curve analysis showed that the net benefit of using the nomogram-based predictive model to predict the risk of recurrence after 2 years was higher when the patient's threshold probability was 0 to 0.990. LIMITATIONS: This was a single-center study. CONCLUSION: A high-precision nomogram-based predictive model was successfully established and validated (with predictive variables including age, pre-Numeric Rating Scale score, and surgery type). We envisage this model will help improve the early identification and screening of high-risk patients for postsurgery pain recurrence of the V1 trigeminal nerve branch.

When the nerve keeps firing: an institutional experience and systematic review on delayed response after microvascular decompression for trigeminal neuralgia.

BACKGROUND: This study aimed to investigate the occurrence of delayed response following microvascular decompression (MVD) in patients with trigeminal neuralgia (TN) and identify potential contributing factors. Additionally, we present two cases with delayed relief observed at our institution. METHOD: Two TN patients with delayed response and clear intra-operative arterial findings are presented in this study. Furthermore, we conducted a systematic review by searching electronic bibliographic databases, including MEDLINE (PubMed), Web of Science, Scopus, and Embase, from inception to 2022. RESULTS: We identified a total of 28 full-text articles involving 322 TN patients who experienced delayed pain relief. Out of these, only 11 studies provided sufficient evidence and were included in the final analysis. Among the patients, 73.46% were female. The mean incidence rate of delayed response after MVD treatment for TN was 10.5%, with a range of 0.95 to 57.14% across different studies. The mean age of these patients was 59.86 years. The reported time to pain relief in the existing reports was at least 4 days post-surgery. In 72.88% of the reported cases, right-side dominance was observed. The majority of delayed cases experienced pain relief within 3 months, with a median time of 1 month. CONCLUSIONS: A thorough examination of the probability of delayed pain relief after MVD for TN and understanding the characteristics of this phenomenon can offer surgeons valuable post-operative guidance and aid in decision-making regarding potential immediate reoperation.

Application of Sequential Thresholding-Based Automated Reconstruction of the Trigeminal Nerve in Trigeminal Neuralgia.

OBJECTIVE: High-resolution magnetic resonance imaging (MRI) of the trigeminal nerve is indispensable for workup of trigeminal neuralgia (TN) before microvascular decompression; however, the evaluation is often subjective and prone to variability. We aim to develop and assess sequential thresholding-based automated reconstruction of the trigeminal nerve (STAR-TN) as an algorithm for segmenting the trigeminal nerve and contacting structures that will allow for a structured method for assessing neurovascular conflict. METHODS: A total of 42 patients with TN who underwent high-resolution MRI before microvascular decompression in 2022 were included in our study. Segmentation of the trigeminal nerve and contacting structures was performed on preoperative MRI scans using STAR-TN. The segmentations were then evaluated for neurovascular conflict and compared to the preoperative radiology and operative notes. Geometric features, including the area of contact and distance to conflict, were extracted. RESULTS: Of the 42 patients, 32 (76.2%) were found to show neurovascular conflict based solely on their STAR-TN segmentations and 10 (23.8%) were found to not show neurovascular conflict. Compared with the intraoperative findings, this resulted in a sensitivity of 78.0% and specificity of 100%. In contrast, assessments of neurovascular conflict by radiologists using only 2-dimensional MRI views had a sensitivity of 68.3% and specificity of 100%. Of the 32 patients with neurovascular conflict, 29 (90.9%) had conflict within the root entry zone. Overall, the patients had a median area of contact of 10.66 mm2. CONCLUSIONS: STAR-TN allows for 3-dimensional visualization and identification of neurovascular conflict with improved sensitivity compared with neuroradiologist assessments from MRI slices.