Radiological and intraoperative findings of a rare case of vestibular paroxysmia.

Vestibular paroxysmia (VP) is a rare condition. The pathogenesis is linked to a neurovascular conflict (NVC) between an abnormal arterial loop and the VII/VIII cranial nerve complex in the cerebello-pontine angle. Due to its rarity, intraoperative findings are only anecdotally reported. Here we reported on a case of VP, showing the radiological images and the intraoperative surgical video of microvascular decompression (MVD). Further we discussed our findings considering the pertinent literature. We think that in case of VP the concordance between the side of tinnitus/hypoacusia and the side of NVC on magnetic resonance imaging should be always looked for before considering MVD as a therapeutic option.

The outcomes of microvascular decompression for primary trigeminal neuralgia: insights from a single-center experience and technical advancements.

Background: Microvascular decompression (MVD) remains the primary surgical treatment for trigeminal neuralgia due to its positive postoperative results. This study aims to evaluate the outcomes of patients with primary trigeminal neuralgia who underwent MVD. Additionally, the paper offers a detailed explanation of the surgical methodology of MVD employed at the neurosurgical hospital in Kazakhstan. Methods: The study involved 165 medical records of patients with trigeminal neuralgia who underwent MVD between 2018 and 2020. Out of these 165 patients, 90 (54.55%) were included in the final analysis and were further evaluated using the Barrow Neurological Institute pain intensity score. Various variables were analyzed, including age, sex, affected side, dermatomes, offending vessel, and surgical intervention type. Moreover, the surgical technique employed at the hospital was described. Results: The average follow-up period after the MVD procedure was 32.78 ± 9.91 months. The results indicated that out of the 90 patients, 80 (88.89%) achieved a good outcome as evidenced by BNI scores I and II. It was observed that patients with affected maxillary dermatomas and those with affected ophthalmic + maxillary dermatomas were more likely to experience fair + poor postsurgery BNI scores. On the other hand, patients with neurovascular conflicts involving the maxillary + mandibular dermatomas demonstrated good BNI scores (p = 0.01). Conclusions: The outcomes of MVD in patients with primary trigeminal neuralgia showed good BNI scores within this study population. The outcome depended on the affected dermatome of the trigeminal nerve with the vessel. Additionally, patient positioning, intraoperative management including small skin incisions, minimal craniotomy, and precise closure of the dura, as well as intraoperative neurolysis, may contribute to achieving good clinical and satisfactory post-surgery aesthetic outcomes.

Long-term outcome of microvascular decompression for typical trigeminal neuralgia with autologous muscle: an analysis of 1025 patients from a developing country.

OBJECTIVE: The objective was to evaluate the long-term outcome of microvascular decompression (MVD) utilizing autologous muscle for trigeminal neuralgia (TGN). METHODS: A retrospective review was performed of all first-time MVD patients for typical classic TGN without prior surgical intervention who were treated between 2000 and 2019 at a tertiary supraregional neurosurgery practice. Demographic characteristics, surgical findings, operative results, complications, and recurrence rates at 1 year, 5 years, and last follow-up were collected. Pain outcome was assessed using the Barrow Neurological Institute (BNI) pain score. The chi-square test with continuity correction was used to compare categorical variables, and Kaplan-Meier curves and Cox regression were used to identify factors associated with recurrence. RESULTS: In total, 1025 patients were studied with a median (interquartile range [IQR]) (range) follow-up of 8 (5-13) (3-20) years. In the immediate postoperative period, 889 patients (86.7%) had complete pain relief and 106 (10.3%) had partial pain relief; neither group required medication, and 30 patients (2.9%) had no relief. One hundred forty-one recurrences (13.8%) occurred over a median (IQR) of 3 (2-6) years after surgery. The proportion of patients without recurrence was 97% at 1 year, 90% at 5 years, 85% at 10 years, 82% at 15 years, and 81% at 20 years. There was no significant difference in the probability of recurrence between patients with complete (114/907 [12.6%] recurrences) or partial (19/106 [17.9%] recurrences) postoperative pain relief (p = 0.124, log-rank test). Patients with venous compression (n = 322) had a significantly higher rate of MVD failure (n = 16 [5%]) compared to those with arterial compression (14/703 [2%]) (p = 0.015, chi-square test). In the Cox proportional hazards model, venous compression and lack of immediate postoperative pain relief had hazard ratios of 1.62 (95% CI 1.16-2.27) and 2.65 (95% CI 1.45-4.82) for recurrence, respectively. One hundred twenty-four (12.1%) complications were documented, including facial numbness (44 [4.3%]), facial nerve palsy (37 [3.6%]), CSF leak (13 [1.3%]), and diplopia (5 [0.5%]), which resolved in all patients. CONCLUSIONS: MVD with autologous muscle provides long-lasting pain relief in TGN patients with vascular compression with minimum morbidity and is a viable alternative to synthetic materials.

Trigeminal neuralgia secondary to epidermoid cyst and neurovascular conflict: An illustrative case with literature review.

Background: Trigeminal neuralgia (TN) is a highly disabling facial pain syndrome, historically known as the suicide disease, in which most cases can be cured with appropriate surgical treatment. Case Description: We present the case of a 43-year-old male farmer with acute, self-limiting episodes of shock-like pain on the left side of the face that started in June of 2021. He was diagnosed with TN and was treated with carbamazepine. Magnetic resonance imaging was performed, which revealed an epidermoid cyst (EC) at the prepontine cistern with an extension to the left cerebellopontine angle. The neurosurgery department at our institution was consulted, which performed surgical tumor resection and Vth cranial nerve decompression. During the resection, a neurovascular conflict (NVC) was identified at the root entry zone. After the resection around the nerve and its whole tract was completed, a microvascular decompression (MVD) was performed. Conclusion: TN secondary to EC in association with a NVC is a rare phenomenon, due to the growth pattern of the EC. TN may remit if an appropriate treatment is carried out. In cases of NVC, an MVD is required apart from an appropriate resection to achieve pain relief.

Management of patients with a neurovascular conflict involving the optic nerve and a non-diseased intracranial artery: Three cases.

Introduction: Determining whether a neurovascular conflict (NVC) involving the anterior visual pathway (AVP) and a non-diseased intracranial artery is amenable for microvascular decompression is challenging. Moreover, it is unclear whether microvascular decompression of the optic nerve is an effective therapy. Research question: What are the outcomes of different treatment strategies for NVCs involving the AVP and a non-diseased intracranial artery? Material and methods: Data on patients with symptomatic NVCs involving the AVP and a non-diseased intracranial artery was collected and included treatment and outcome parameters. The case series was drafted in accordance with the CARE guidelines. Results: Three patients aged 53,53 and 55 visited our out-patient clinic with a suspected symptomatic NVC between the optic nerve and a non-diseased intracranial artery. A conservative treatment was opted for in the first patient aimed at treating her glaucoma, with temporary improvement of symptoms. Microvascular decompression of the optic nerve was performed in two patients. One operated patient developed post-operative complications resulting in posterior circulation perfusion decline, while the other experienced a worse tunnel vision with a decrease in visual acuity. Discussion and conclusion: The diagnosis of a symptomatic NVC between the AVP and a non-diseased intracranial artery should be considered with caution, i.e. after exclusion of all other causes. Microvascular decompression can be performed but does not necessarily improve symptoms. A better understanding of the pathophysiological mechanisms underlying these NVCs is warranted to determine the benefit of microvascular decompression of the optic nerve.

[Dolichoectasia of the basilar artery caused by cystic medial degeneration, as a cause of neurovascular conflict with damage to the trigeminal, facial and vestibulocochlear nerves]. / Dolikhoektaziya bazilyarnoi arterii, obuslovlennaya kistoznoi medial'noi degeneratsiei, kak prichina neirovaskulyarnogo konflikta s porazheniem troinichnogo, litsevogo i vestibulokokhlearnogo nervov.

Cystic medial degeneration (Gsell-Erdheim syndrome, cystic medial necrosis) is considered to be a nonspecific histological manifestation of a group of diseases characterized by degenerative changes in the media, affecting primarily the aorta and adjacent branches, which leads to destruction of the vessel wall, followed by its expansion and, possibly, rupture. The authors describe a case of a 65-year-old female patient with a neurovascular conflict of the three cranial nerves with dolichoectatic basilar artery due to cystic medial degeneration. As a result, the patient has clinical manifestations in the form of hemifacial spasm, trigeminal neuralgia and vestibular paroxysmia. Data from instrumental studies and treatment provided are presented. Neurovascular conflict can be identified in various diseases and is characterized by the complex etiology. The most common clinical manifestations of neurovascular conflict are trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, and vestibular paroxysmia.

Correlation of Prepontine Cisternal Space Thickness with the Severity of Neurovascular Conflict and its Role in Predicting Outcome of Medical Management in Cases of Trigeminal Neuralgia.

Background: Trigeminal neuralgia (TN) is a debilitating disorder that presents with sudden onset of severe, unilateral, paroxysmal, and lancinating pain usually lasting for few seconds to few minutes. Aims and Objectives: The main aim of our study was to correlate the prepontine cisternal space thickness, with a severity of neurovascular compression (NVC) and percentage reduction of pain (patient outcome). Materials and Methods: Ours is an observational prospective study of 40 patients presenting with TN for magnetic resonance imaging in our department. Patients were followed up on medical treatment and their pain severity evaluated on their follow-up visit. Patients were divided into two groups based on prepontine cisternal space (Group A: ≤4 mm, Group B: >4 mm) and into three groups based on the percentage reduction of pain, Group 1 (0-35%), Group 2 (36-70%), and Group 3 consisted of patients with pain reduction of more than 70%. Ipsilateral prepontine cisternal space thickness was correlated with grade of NVC and percentage reduction of pain. Results: Mean percentage of pain reduction in group A and group B was 34.12 and 60.68%, respectively. Approximately 23.80% of grade1 NVC were seen in group A and 76.20% in group B, while 80% of grade 3 NVC were seen in group A and only 20% were seen in group B. Conclusion: There was poor response to medical treatment, in patients with narrowed prepontine cisternal space thickness with an inverse relationship between the grade of NVC and cisternal space thickness.

Microvascular decompression for trigeminal neuralgia: a single-center experience with 516 cases, including 32 patients with multiple sclerosis.

BACKGROUND AND OBJECTIVES: To evaluate the effectiveness and long-term pain relief of microvascular decompression (MVD) for "typical" trigeminal neuralgia (TN), including patients affected by multiple sclerosis (MS). METHODS: Between January 2011 and December 2022, 516 consecutive patients presenting with trigeminal neuralgia and a diagnosed neurovascular conflict at MRI underwent microvascular decompression surgery in our neurosurgery department. Ten surgeons with different ages and experiences performed the surgical procedures. Pain improvement, re-operation rate, and complication rates were retrospectively collected and analyzed. RESULTS: 516 patients were included (214 males 302 females, ranging from 12 to 87 years), including 32 patients with multiple sclerosis. Neurovascular compression was found in all cases during surgery. Barrow Neurological Institute pain intensity scale with a score of I was achieved in 404 patients (78,29%), a score II or III was obtained in 100 cases (19,37%) and a score of IV and V in 12 patients (2,32%). In the multiple sclerosis subset of patients, a BNI score of I was achieved in 21/32 (65.62%). The pain recurrence rate of our series was 15.11%. The follow-up for all patients was at least of 13 months, with a mean follow-up of 41.93 months (± 17.75 months, range 13-91 months). Neither intraoperative mortality nor major intra-operative complications occurred in the analyzed series. The re-operation rate was 12.98%. Thermorhizotomy, percutaneous balloon compression, cyber-knife radiosurgery, or new MVD were the surgical techniques utilized for re-operations. CONCLUSIONS: MVD may be considered an effective and safe surgical technique for TN, and in patients affected by multiple sclerosis, it may be proposed even if a less favorable outcome has to be expected with respect to classic TN patients. Larger studies focusing on the relation of multiple sclerosis with neurovascular compression are required.

The role of artificial intelligence in the management of trigeminal neuralgia.

Trigeminal neuralgia (TN) is the most frequent facial pain. It is difficult to treat pharmacologically and a significant amount of patients can become drug-resistant requiring surgical intervention. From an etiologically point of view TN can be distinguished in a classic form, usually due to a neurovascular conflict, a secondary form (for example related to multiple sclerosis or a cerebello-pontine angle tumor) and an idiopathic form in which no anatomical cause is identifiable. Despite numerous efforts to treat TN, many patients experience recurrence after multiple operations. This fact reflects our incomplete understanding of TN pathogenesis. Artificial intelligence (AI) uses computer technology to develop systems for extension of human intelligence. In the last few years, it has been a widespread of AI in different areas of medicine to implement diagnostic accuracy, treatment selection and even drug production. The aim of this mini-review is to provide an up to date of the state-of-art of AI applications in TN diagnosis and management.

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

BACKGROUND: It 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. METHODS: In 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. RESULTS: A 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. DISCUSSION: The 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.

Outcome after microvascular decompression for trigeminal neuralgia in a single center-relation to sex and severity of neurovascular conflict.

BACKGROUND: Trigeminal neuralgia (TN), a severe type of facial pain, is mainly caused by a neurovascular conflict (NVC). The severity of the NVC seems associated with the outcome following microvascular decompression (MVD) surgery. This study aimed to investigate the outcome after MVD and whether it is affected by NVC severity and sex. METHODS: TN patients (n = 109) were followed for 5 to 10 years after MVD. Barrow Neurology Index (BNI), Patients Global Impression of Change (PGIC), complications, and time to relapse were evaluated. The NVC severity was retrospectively reviewed from presurgical MRI. Demographic and clinical factors and NVC severity were analyzed for potential association with outcome after MVD. RESULTS: The success rate (BNI ≤ 2) was 80% after 5 to 10 years follow-up for TN patients with severe NVC (grade 2-3) and 56% for TN patients with mild NVC (grade 0-1, P = 0.003). No sex difference was observed in outcome for patients with both mild (P = 0.924) and severe NVC (P = 0.883) respectively. Three patients (2.8%) during the hospital stay, and two patients (1.8%) at 6 weeks, experienced a complication requiring invasive treatment. At long-term 52/109 patients (47.7%) reported some type of persistent adverse event, of which the majority were mild and required no treatment. CONCLUSIONS: MVD offers an 80% probability of long-term pain relief in TN patients with severe NVC, with low frequency of serious complications. NVC severity significantly affects outcome after MVD, while no sex differences in outcome were found. In consistency with previous work, the results stress the importance of adequate neuroradiological assessment of the NVC for preoperative patient selection.

[Early results of intraoperative neurophysiological monitoring in surgical treatment of hemifacial spasm]. / Analiz blizhaishikh rezul'tatov intraoperatsionnogo neirofiziologicheskogo monitoringa pri khirurgicheskom lechenii gemifatsial'nogo spazma.

BACKGROUND: Neurophysiological monitoring in surgery for hemifacial spasm has been used since the 1990s, when Moller et al. demonstrated the effectiveness of intraoperative assessment of lateral spread response (LSR) regarding postoperative outcomes. Currently, there are conflicting data on effectiveness and feasibility of this technique. Widespread hemifacial spasm determines the relevance of neurophysiological monitoring in surgical treatment of these patients. OBJECTIVE: To evaluate the effectiveness of various methods of intraoperative neurophysiological monitoring in surgical treatment of hemifacial spasm regarding early postoperative outcomes. MATERIAL AND METHODS: The study group included 43 patients (8 men and 35 women) aged 26-68 years. We assessed severity of hemifacial spasm using the SMC Grading Scale. All patients underwent vascular decompression of the facial nerve under neurophysiological control: monitoring of transcranial motor evoked potentials from facial muscles (m. orbicularis oculi, m. orbicularis oris, m. mentalis) and recording unilateral LSR. The control group included 23 patients (4 men and 19 women) aged 29-83 years. In this group, facial nerve decompression was performed without neurophysiological control. The effect of neurophysiological monitoring on postoperative outcomes (in-hospital period and 3 postoperative months) after vascular decompression of the facial nerve was assessed using the SMC Grading Scale. We considered severity and incidence of spasms. RESULTS: Thirty-one (72%) patients in the main group had no spasms of mimic muscles at discharge. In the control group, there were no spasms in 15 patients (65%). At the same time, there were fewer Grade I patients in the control group (12%) compared to the main group (26%). Moreover, 27 (66%) and 12 (52%) patients were free from episodes of hemifacial spasm in both groups, respectively. Patients with hemifacial spasm grade I-II comprised 29% in the main group and 34% in the control group. The number of relapses within three months increased in the control group (13%). CONCLUSION: Intraoperative monitoring of transcranial motor evoked potentials from the facial muscles and LSR during vascular decompression of the facial nerve increases the efficiency of surgery for hemifacial spasm in early postoperative period. Less number of relapses and lower intensity of hemifacial spasm necessitate neurophysiological monitoring in neurosurgical treatment of these patients.

Absence of Meckel's Cave with Trigeminal Neuralgia: A Case Report.

Trigeminal neuralgia (TN) is a disabling painful condition along the course of the sensory distribution of the trigeminal nerve that most commonly occurs due to vascular compression or conflict at the root entry zone of the trigeminal nerve. We report a 27-year-old female patient who presented with pain and an electric shock-like sensation on the right side of her face that started three years ago. Magnetic resonance imaging of the brain was done and revealed no neurovascular conflict along the course of the trigeminal nerve. The absence of Meckel's cave with atrophy of the cisternal segment of the trigeminal nerve on the affected side was reported. The absence of Meckel's cave is an exceedingly rare cause of TN, and only a handful of reported cases in the literature suggest the association between them.

Isolated Internal Ophthalmoplegia from Posterior Cerebral Artery Neurovascular Conflict.

We report a rare case of recurrent isolated internal ophthalmoplegia attributed to oculomotor nerve (CN III) compression by the posterior cerebral artery (PCA). A 30-year-old female patient presented with recurrent right-sided headaches, right periorbital pain, and slight anisocoria. Slit-lamp examination revealed normal anterior and posterior segments except for vermiform movements of the right pupil with a temporal hyporeactive flat area. Tonic pupils were ruled out with pilocarpine 0.1% testing. Suspecting an internal ophthalmoplegia, magnetic resonance imaging was ordered which demonstrated the right CN III indented by the PCA, fulfilling the criteria of a neurovascular conflict. The evaluation of unilateral mydriasis from internal ophthalmoplegia should prompt neuroimaging with exclusion of aneurysmal or compressive lesions. CN III palsy can rarely be caused by vascular anatomical variants because of the proximity of the posterior intracranial circulation and CN III. Newer, more precise imaging techniques will better help characterize neurovascular conflicts presenting as cranial nerve palsies.

Neurovascular conflict and sudden unilateral sensorineural hearing loss: coincidence or coexistence?

OBJECTIVE: To study the association between neurovascular conflict (NVC) of the 8th cranial nerve (CN8) and unilateral sudden sensorineural hearing loss SSNHL (SSNHL). METHODS: A systematic literature search of "MEDLINE" via "PubMed," "Embase," and "Google-Scholar" was conducted. Meta-analysis of pooled data was performed for NVC prevalence of SSNHL affected ears versus controls. RESULTS: The literature search identified 941 publications, of which, 9 included in qualitative synthesis (1030 ears) and 5 in quantitative synthesis (484 ears). NVC was as prevalent as 0.8-69% for affected ears and as 19-57% for controlled ears. No association between MRI protocol and NVC prevalence was proved. An odds ratio of 1.05 (95% confidence interval = 0.79-1.39) was calculated for association of NVC in unilateral SSNHL ears versus controls. CONCLUSION: The prevalence of NVC of CN8 in unilateral SSNHL affected ears is not significantly bigger than controls. Hence, NVC of CN8 is probably NOT associated with unilateral SSNHL.

Assessment of outcomes in consecutive patients undergoing dorsal scapular nerve decompression.

OBJECTIVE: Periscapular pain has a broad differential diagnosis. Dorsal scapular neuropathy is part of that differential diagnosis but is often forgotten by clinicians, leading to delayed diagnosis, chronic pain, and potentially worse outcomes. The objective of this study was to describe our method for diagnosis, surgical technique, intraoperative findings, and outcomes in consecutive patients undergoing dorsal scapular nerve (DSN) decompression. METHODS: A retrospective cohort study was performed to compile and describe outcomes for consecutive patients (n = 21) who underwent DSN decompression by a single surgeon during the period between August 2018 and February 2021. The primary outcome was change in visual analog scale (VAS) score for periscapular pain between baseline and 6 months postoperatively. Secondary outcomes included change in VAS score for overall pain, change in Disabilities of the Arm, Shoulder, and Hand (DASH) score, and change in the Zung Self-Rating Depression Scale (Zung SDS) between baseline and 6 and 12 months postoperatively. RESULTS: Patients undergoing DSN decompression showed significant improvement in VAS score for periscapular pain between baseline and 6 months postoperatively (mean score 54.0 vs 26.8, respectively; p < 0.001). Fifteen of 21 patients (71%) had a good outcome (score improvement ≥ 20). Disability (as determined by DASH scores) was significantly improved at 6 and 12 months postoperatively. The only factor that was predictive of outcome was symptom duration, with longer symptom duration predicting a poor outcome. CONCLUSIONS: Surgical treatment of dorsal scapular neuropathy is associated with significant improvements in pain and disability, and these improvements are durable. Morbidity associated with surgical treatment is low.

Clinical outcome after microvascular decompression for trigeminal neuralgia: a systematic review and meta-analysis.

Microvascular decompression (MVD) is considered an effective treatment for trigeminal neuralgia (TN). However, the anatomical and clinical variables associated with a better outcome are not fully examined. The authors performed a systematic review and meta-analysis of the literature investigating the immediate and long-term clinical results of MVD for TN, and the impact of the anatomical features of the neurovascular conflict on the outcome. The systematic search of three databases was performed for studies published between January 1990 and November 2021. PRISMA guidelines were followed. Random-effects meta-analysis was used to pool the analyzed outcomes, and random-effect meta-regression was used to examine the association between the effect size and potential confounders. A funnel plot followed by Egger's linear regression was used to test publication bias. A total of 9 studies were included in this analysis, including 2102 patients with trigeminal neuralgia. The immediate post-operative rate of BNI I was 82.9%, whereas surgical failure (BNI IV-V) was reported in approximately 2.6% of patients. CSF leak was the most common postoperative complication (2.4%). The rate of BNI I at last follow up was 64.7% (p < 0.01), showing a significant negative correlation after multiple meta-regression with the rate of patients with isolated venous conflict (p < 0.01). On the other hand, the evidence of an arterial conflict proved is positive association with a favorable outcome (p < 0.01). At the last follow-up, BNI IV-V was reported in 19.2% (95% CI 8.9-29.5%, p < 0.01, I2 = 97.3%). This meta-analysis confirms the safety and efficacy of MVD for TN. The occurrence of serious postoperative complications is very low. The long-term outcome is associated with the type of vascular structure involved, being pure venous conflict associated with a higher risk of surgical failure. These findings should be considered when planning surgery for patients with TN.

Delayed pain relief in patients with trigeminal neuralgia following microvascular decompression: A single-central retrospective study.

Background: Compared to hemifacial spasm after microvascular decompression (MVD), delayed relief (DR) rarely occurs in patients with trigeminal neuralgia (TGN). Objective: To analyze the characteristics of post-MVD DR in TGN patients to provide useful clues for the clinical differential diagnosis of postoperative DR. Methods: The clinical data of all patients with TGN who underwent MVD in our center from January 1, 2016, to December 31, 2020, were reviewed retrospectively. Results: In 272 TGN MVD patients, DR occurred in nine patients (3.3%) during the follow-up periods of 1-6 years. During surgery, all nine DR-TGN patients were identified as having neurovascular conflicts (NVCs), involving the offending artery (OA) in eight patients (two OAs in two patients) and both an artery and a vein in the other patient. The compression site was near the root entry zone (REZ) in most DR patients (7/9). Delayed relief was relieved in seven patients within 5 days after surgery and within 30 days in the other two patients. No recurrence or serious complications were observed within the mean 4 (1-6)-year follow-up duration. Conclusion: Delayed relief rarely occurs in TGN patients after MVD. Neurovascular conflicts located at the REZ and NVC of grade III may be two important factors contributing to DR in TGN patients. Delayed relief may occur when the pain gradually improves after the operation and responds effectively to a small dose of carbamazepine. The recurrence rate of TGN seems even lower in such patients.