IV Thrombolysis in Basilar Artery Occlusion: Outcomes and Comparison With Endovascular Thrombectomy.

BACKGROUND AND OBJECTIVES: Recanalization is considered a prerequisite for favorable outcome in basilar artery occlusion (BAO). Intravenous thrombolysis (IVT) has been successfully used for eligible patients with BAO well beyond the 4.5-hour time window but has been largely underrepresented in the best medical management arms in recent randomized controlled trials of recanalization therapy in BAO. We aimed to analyze the outcomes of patients with BAO treated with IVT only and to compare IVT with endovascular thrombectomy (EVT). METHODS: This observational single-center, retrospective cohort study included consecutive patients with BAO treated with IVT and/or EVT up to 48 hours of symptom onset during 1995-2022. The primary outcome was favorable functional outcome (modified Rankin Scale 0-3) at 3 months collected by a stroke physician by phone. In the first part, we described the outcomes and factors associated with functional outcome in the IVT-only cohort during 1995-2022. In the second part, we used doubly robust inverse probability-weighted regression adjustment models to compare functional outcome of patients treated with IVT vs EVT+/-IVT during 2010-2022. RESULTS: In the whole cohort of 376 patients with acute BAO treated with recanalization therapy, 245 (65.2%) received only IVT. In the IVT-only cohort, most patients had moderate-to-severe clinical presentation (median NIH Stroke Scale 18) but no extensive early ischemic changes in the posterior circulation on admission. Half of them had onset-to-treatment time over 6 hours. 46.5% of the IVT-treated patients achieved 3-month favorable functional outcome, whereas mortality was 35.9%. sICH occurred in 11.1%. In a multivariable analysis, younger age, milder symptom severity, and less baseline ischemic changes predicted favorable functional outcome. In the 2010-2022 cohort, when compared with patients treated with EVT+/-IVT (n = 121), the IVT-only cohort (n = 122) had higher odds for favorable functional outcome (IVT 58.2% vs EVT 43.0% (aOR 2.82 [95% CI 1.31-6.05]). DISCUSSION: IVT alone produced outcomes comparable with those in recent trials of endovascular BAO recanalization. Furthermore, in head-to-head comparison in our cohort, the IVT-only approach was more often associated with favorable outcome than EVT+/-IVT. Thus, it should not be overlooked as the first-line recanalization therapy in acute BAO, even in longer time windows. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that tPA is as effective as thrombectomy for basilar artery thrombosis.

Basilar artery perforator aneurysms: a comparison with non-perforator saccular aneurysms.

BACKGROUND: Basilar artery perforator aneurysms (BAPAs) are rare. There is no systematic description of their presentation, imaging, natural history and outcomes and how these compare to conventional non-perforator aneurysms. Thus, the authors in this study aimed to compare BAPAs to non-perforator aneurysms. METHODS: Cases were identified from a prospective neurovascular database, notes and imaging retrospectively reviewed and compared to a consecutive series of patients with non-perforator aneurysms. Blood volume on CT and vessel wall imaging (VWI) were compared to controls. RESULTS: 9/739 patients with aneurysmal subarachnoid haemorrhage (aSAH) harboured BAPAs. Compared to 103 with aSAH from posterior circulation aneurysms, they were more likely to be male (6/9, p = 0.008), but of equal severity (4/9 poor grade, p = 0.736) and need of CSF drainage (5/9, p = 0.154). Blood volume was similar to controls (30.2 ml vs 26.7 ml, p = 0.716). 6/9 BAPAs were initially missed on CTA. VWI showed thick (2.9 mm ± 2.7) bright enhancement (stalk ratio 1.05 ± 0.12), similar to controls with ruptured aneurysms (0.95 ± 0.23, p = 0.551), and greater than unruptured aneurysms (0.43 ± 0.11, p < 0.001). All were initially managed conservatively. Six thrombosed spontaneously. Three grew and had difficult access with few good endovascular options and were treated through a subtemporal craniotomy without complication. None rebled. At 3 months, all presenting in poor grade were mRS 3-4 and those in good grade mRS 1-2. CONCLUSIONS: Despite their small size, BAPAs present with similar volume SAH, WFNS grade and hydrocephalus to other aneurysms. They are difficult to identify on CTA but enhance strikingly on VWI. The majority thrombosed. Initial conservative management reserving treatment for growth was associated with no rebleeds or complications.

Treatment strategies for saccular anterior inferior cerebellar artery aneurysms: a systematic review.

INTRODUCTION: The anterior inferior cerebellar artery (AICA) plays a crucial role in cerebellar blood supply, and AICA aneurysms are relatively rare, comprising less than 1-1.5% of all brain aneurysms. Understanding their clinical scenarios, management approaches, and outcomes is essential. This systematic review analyzes data from 86 studies to comprehensively explore AICA aneurysms. MATERIALS AND METHODS: The process of obtaining relevant research, which includes patients with AICA aneurysms, was carried out using the PubMed, Web of Science, and Scopus databases. This review exclusively included extensive papers written in English. The search included the MeSH phrases "Anterior inferior cerebellar artery aneurysm" and "AICA aneurysm." Microsurgical and endovascular treatments were compared using statistical analysis, exploring demographics, risk factors, treatment modalities, and clinical outcomes. RESULTS: The review includes 85 case reports and one retrospective study, totaling 140 patients. The study reveals a diverse patient profile with a slight female predominance (65%), a mean age of 50.7 years, and an 82.86% prevalence of no identified risk factors. Ruptured aneurysms accounted for 55%, with microsurgery and endovascular procedures accounting for 70.71% and 27.86%, respectively. The mortality rate was 2.86%, and no significant differences were found in rebleed, recurrence, or mortality rates between treatment groups. CONCLUSION: Microsurgical and endovascular interventions demonstrate comparable effectiveness, with microsurgery showing superiority in specific situations. Therefore, tailoring treatment is crucial to individual patient needs. Subgroup analyses highlight demographic-specific trends, guiding clinicians in managing this rare pathology.

Composition of encephalic arteries and origin of the basilar artery are different between vertebrates.

Intracranial arterial anatomy is lacking for most mammalian and non-mammalian model species, especially concerning the origin of the basilar artery (BA). Enhancing the knowledge of this anatomy can improve animal models and help understanding anatomical variations in humans. We have studied encephalic arteries in three different species of birds and eight different species of mammals using formalin-fixed brains injected with arterial red latex. Our results and literature analysis indicate that, for all vertebrates, the internal carotid artery (ICA) supplies the brain and divides into two branches: a cranial and a caudal branch. The difference between vertebrates lies in the caudal branch of the ICA. For non-mammalian, the caudal branch is the origin of the BA, and the vertebral artery (VA) is not involved in brain supply. For mammals, the VA supplies encephalic arteries in two different ways. In the first type of organization, mostly found in ungulates, the carotid rete mirabile supplies the encephalic arteries, the caudal branch is the origin of the BA, and the VA is indirectly involved in carotid rete mirabile blood supply. The second type of encephalic artery organization for mammals is the same as in humans. The caudal branch of the ICA serves as the posterior communicating artery, and the BA originates from both VAs. We believe that knowledge of comparative anatomy of encephalic arteries contributes to a better understanding of animal models applicable to surgical or radiological techniques. It improves the understanding of rare encephalic variations that may be present in humans.

Trials of endovascular thrombectomy of basilar-artery occlusion compared to real-life data.

BACKGROUND: Two recent clinical trials showed mechanical thrombectomy (MT) of basilar-artery occlusions (BAO) in stroke to be safe and effective: Endovascular Treatment for Acute BAO (ATTENTION) and BAO Chinese Endovascular (BAOCHE). The trials restricted patient inclusion on both age and pre-stroke mRS, and with both trials conducted in China, population differences may affect generalisability of the trial results. METHODS: Consecutive patients with BAO undergoing MT were registered from 2017 to 2021 with retrospective data collection at a single centre with a predominantly Caucasian catchment population of 2.7 million. Age and pre-stroke modified Rankin Scale (mRS) were not absolute contraindications for MT. We present functional outcome as mRS at 90 days, patient characteristics and procedural safety compared to the trial intervention groups. RESULTS: Of the 108 included patients, 50 % achieved mRS 0-3 at 90 days and mortality was 32 %, which was no different from ATTENTION (46 %, p = 0.40, 37 %, p = 0.31, respectively) and BAOCHE (46 %, p = 0.50, 31 %, p = 0.93). Pre-stroke mRS 0 was seen in 62 %, 89 %, and 77 % of the study patients, ATTENTION, and BAOCHE, respectively. Proximal segment BAO was less common (22 % vs. 31 %, p = 0.04, and 65 %, p < 0.01) and intracranial stenting less frequently used (9 % vs. 40 % and 55 %, p < 0.01) in study patients compared to ATTENTION and BAOCHE, respectively. CONCLUSION: Outcome of MT in BAO stroke in a clinical patient cohort was similar to recent trials, despite broader patient inclusion and differences in both occluded BAO segment and use of stenting. Our study suggest that MT is safe and effective in a Caucasian population.

Technical Risk Stratification Nomogram Model for 90-Day Mortality Prediction in Patients With Acute Basilar Artery Occlusion Undergoing Endovascular Thrombectomy: A Multicenter Cohort Study.

BACKGROUND: This study aimed to establish and validate a nomogram model for predicting 90-day mortality in patients with acute basilar artery occlusion receiving endovascular thrombectomy. METHODS AND RESULTS: A total of 242 patients with basilar artery occlusion undergoing endovascular thrombectomy were enrolled in our study, in which 172 patients from 3 stroke centers were assigned to the training cohort, and 70 patients from another center were assigned to the validation cohort. Univariate and multivariate logistic regression analyses were adopted to screen prognostic predictors, and those with significance were subjected to establish a nomogram model in the training cohort. The discriminative accuracy, calibration, and clinical usefulness of the nomogram model was verified in the internal and external cohorts. Six variables, including age, baseline National Institutes of Health Stroke Scale score, Posterior Circulation-Alberta Stroke Program Early CT (Computed Tomography) score, Basilar Artery on Computed Tomography Angiography score, recanalization failure, and symptomatic intracranial hemorrhage, were identified as independent predictors of 90-day mortality of patients with basilar artery occlusion and were subjected to develop a nomogram model. The nomogram model exhibited good discrimination, calibration, and clinical usefulness in both the internal and the external cohorts. Additionally, patients were divided into low-, moderate-, and high-risk groups based on the risk-stratified nomogram model. CONCLUSIONS: Our study proposed a novel nomogram model that could effectively predict 90-day mortality of patients with basilar artery occlusion after endovascular thrombectomy and stratify patients with high, moderate, or low risk, which has a potential to facilitate prognostic judgment and clinical management of stroke.

Second trimester screening for the basilar artery: a new approach using slowflowHD.

OBJECTIVES: Sonographic evaluation of the basilar artery is challenging, and a limited number of reports are available about the prenatal period, as manual positioning of probes is technically difficult. The objective of this study was to describe a sonographic transabdominal approach based on slowflow HD for screening of the basilar artery during the second trimester scan. METHODS: A total of 49 women who were enrolled in a second trimester screening were included when the fetus was in the occipitoanterior position. Dopper screening of the cerebral artery was performed, which revealed the "Y" sign indicating the basilar trunk arising from two vertebral arteries in the axial oblique view when the probe was located around the junction of the vertebral processes and occipital bone and was superior to the first vertebral body, sloping slightly to the cephalic side. The Doppler ultrasound probe was placed perpendicular to the basilar artery. The flow direction was below the baseline, away from the probe in the basilar artery, consistent with a caudocephalic orientation. Peak systolic and diastolic velocities were measured. RESULTS: The basilar artery was identified in all 49 fetuses, with a mean gestational age of 22 weeks (range 20 to 26 weeks). The mean peak systolic velocity of the basilar artery was 15.8 cm/second (range 9.12-26.44 cm/second). There was a slight increase in peak systolic velocity according to the gestational age of the fetus. CONCLUSIONS: This study demonstrated that evaluation of the basilar artery can be performed during the second trimester via a new transabdominal approach involving slowflow HD.

Efficacy of Endovascular Thrombectomy in Acute Basilar Artery Occlusion with Low PC-ASPECTS: A Nationwide Prospective Registry-Based Study.

OBJECTIVE: We evaluated the efficacy of endovascular thrombectomy (EVT) on the functional outcome of patients with acute basilar artery occlusion and low posterior circulation acute stroke prognosis early computed tomography score (PC-ASPECTS). METHODS: We identified patients with acute ischemic stroke due to basilar artery occlusion and PC-ASPECTS of 6 or less, presenting within 24 h between August 2008 and April 2022. The primary outcome was a favorable functional outcome, defined as a modified Rankin Scale (mRS) score of 0-3 at 90 days. The secondary outcomes included an mRS score of 0-2, a favorable shift in the ordinal mRS scale, the occurrence of symptomatic intracranial hemorrhage (sICH), and mortality at 90 days. We compared the outcome of patients treated with EVT and those without EVT, using the inverse probability of treatment weighting methods. RESULTS: Out of 566 patients, 55.5% received EVT. In the EVT group, 106 (33.8%) achieved favorable outcomes, compared to 56 patients (22.2%) in the conservative group. EVT significantly increased the likelihood of achieving a favorable outcome compared to conservative treatment (relative risk [RR] 1.39, 95% confidence interval [CI], 1.11-1.74, p = 0.004). EVT was associated with a favorable shift in the mRS (RR 1.85, 95% CI, 1.49-2.29, p < 0.001) and reduced mortality without an increase in the risk of sICH. It did not have an impact on achieving an mRS score of 0-2. INTERPRETATION: Patients with acute basilar artery occlusion and a PC-ASPECTS of 6 or less might benefit from EVT without an increasing sICH. ANN NEUROL 2024;95:788-799.

Adjunct Intraarterial or Intravenous Tirofiban Versus No Tirofiban After Successful Recanalization of Basilar Artery Occlusion Stroke: The BASILAR Registry.

BACKGROUND: Approximately half of patients who achieve successful reperfusion do not achieve functional independence. The present study sought to investigate the clinical outcomes and safety of intraarterial or intravenous tirofiban as adjunct therapy in patients with acute basilar artery occlusion who had achieved successful recanalization with endovascular treatment. METHODS AND RESULTS: In the national, prospective BASILAR (Endovascular Treatment for Acute Basilar Artery Occlusion Study) registry, 458 patients who met inclusion criteria were divided into 3 groups based on tirofiban administration (no tirofiban, n=262; intravenous tirofiban, n=101; intraarterial+intravenous tirofiban, n=95). Their clinical outcomes were compared with 90-day modified Rankin Scale scores. Adjusted odds ratios (aORs) and 95% CIs were obtained by logistic regression models and propensity score matching. Safety outcomes included any intracranial hemorrhage (ICH), symptomatic ICH, and mortality. Among 458 included patients, 184 (40.2%) achieved a favorable outcome (modified Rankin Scale score 0-3). There were no differences between the intravenous tirofiban group and the no tirofiban group in terms of safety and clinical outcomes (all P>0.05). Compared with the no tirofiban group, the intraarterial+intravenous tirofiban group had higher odds of 90-day modified Rankin Scale score 0 to 3 (aOR, 2.44 [95% CI, 1.30-4.64], P=0.006) and lower 3-month mortality (aOR, 0.38 [95% CI, 0.19-0.71], P=0.002) without an increase in any ICH (aOR, 0.34 [95% CI, 0.09-1.01], P=0.07) or symptomatic ICH (aOR, 0.23 [95% CI, 0.03-0.90], P=0.05). Similar results of intraarterial+intravenous tirofiban on improving clinical outcomes were detected in novel cohorts constructed by propensity score matching. CONCLUSIONS: Intraarterial+intravenous rather than intravenous tirofiban improved clinical outcomes without increasing the frequency of symptomatic ICH among patients with basilar artery occlusion after successful endovascular treatment. Further studies are needed to delineate the roles of intraarterial+intravenous tirofiban in patients with basilar artery occlusion receiving endovascular treatment.

Ruptured basilar artery perforator aneurysm mimicking superior cerebellar artery aneurysm.

BACKGROUND AND IMPORTANCE: The diagnosis of basilar artery perforator aneurysm is difficult due to their small size, with high rates of negative angiography. Furthermore, due to the considerable variation of basilar artery perforator (BAP), even if an aneurysm originates from a BAP, it is often difficult to clearly identify its origin on angiography. CLINICAL PRESENTATION: A 46-female patient presented with World Federation of Neurological Surgeons Scale 1 subarachnoid hemorrhage. Initial imaging study, including digital subtraction angiography (DSA), revealed no vascular lesions. Two-week after admission, DSA revealed an aneurysm arising from the left superior cerebellar artery (SCA). Endovascular coil embolization was planned first. However, aneurysm selection using microcatheter was failed. Then, surgical approach was done via pre-temporal approach. We identified SCA, but there was no aneurysm. Further dissection revealed an aneurysm arising from basilar artery perforator, which was overlapped by SCA. The parent artery of the aneurysm arose from juxtaproximal to the orifice of left SCA, and crossed SCA at the juxtadistal to the aneurismal sac. Complete clip occlusion was done preserving BAP. After the surgery, the patient developed diplopia without extraoccular movement limitations. Two-month after the surgery, she was fully recovered without any neurologic deficits. CONCLUSION: It is crucial to adequately consider the possibility of open surgery as a viable option in case that endovascular treatment of aneurysms originated from the distal segment of basilar artery proves unsuccessful.

Brain artery diameters and risk of dementia and stroke.

INTRODUCTION: We tested the association of brain artery diameters with dementia and stroke risk in three distinct population-based studies using conventional T2-weighted brain magnetic resonance imaging (MRI) images. METHODS: We included 8420 adults > 40 years old from three longitudinal population-based studies with brain MRI scans. We estimated and meta-analyzed the hazard ratios (HRs) of the brain and carotids and basilar diameters associated with dementia and stroke. RESULT: Overall and carotid artery diameters > 95th percentile increased the risk for dementia by 1.74 (95% confidence interval [CI], 1.13-2.68) and 1.48 (95% CI, 1.12-1.96) fold, respectively. For stroke, meta-analyses yielded HRs of 1.59 (95% CI, 1.04-2.42) for overall arteries and 2.11 (95% CI, 1.45-3.08) for basilar artery diameters > 95th percentile. DISCUSSION: Individuals with dilated brain arteries are at higher risk for dementia and stroke, across distinct populations. Our findings underline the potential value of T2-weighted brain MRI-based brain diameter assessment in estimating the risk of dementia and stroke.

Development and validation of a novel scoring system for acute ischemic stroke.

BACKGROUND: This study aimed to assess the clinical application of the Artery Occlusion Image Score (AOIS), a new metric based on computed tomographic angiography (CTA) that reflects the severity of occlusive changes in the main intracranial arteries. MATERIALS AND METHODS: Patients diagnosed with acute ischemic stroke (AIS) were divided into three groups: anterior circulation infarcts (ACI group), posterior circulation infarcts (PCI group), and both anterior and posterior circulation infarcts (ACI + PCI group). The sensitivity and specificity of AOIS were evaluated using the Basilar Artery on Computed Tomography Angiography (BATMAN) score, the Clot Burden Score (CBS), and the National Institutes of Health Stroke Scale (NIHSS) as comparators through receiver-operating characteristic (ROC) curve analysis. RESULTS: The final analysis included 439 consecutive patients. In the ACI group, AOIS demonstrated high sensitivity (86.3%) and specificity (85.0%) and outperformed CBS in predicting patient prognosis. In the PCI group, AOIS also showed high sensitivity (88.9%) and specificity (90.0%) and outperformed BATMAN in predicting patient prognosis. In the ACI + PCI group, AOIS positively correlated with the NIHSS score (Spearman's ρ = 0.602, P < .001). Additionally, the scoring time of AOIS did not significantly differ from CBS and BATMAN. CONCLUSION: AOIS is a convenient and reliable method for guiding treatment and predicting outcomes in patients with ACI or/and PCI. Furthermore, AOIS is the first CTA-based scoring system that covers both the anterior and posterior circulation, providing a convenient and reliable evaluation for patients with concurrent acute ischemic stroke in both circulations.

Persistent trigeminal artery in a patient with moyamoya disease:a case report and literature review.

BACKGROUNDS: Persistent trigeminal artery (PTA) is a rare anastomosis between internal carotid artery (ICA) and basilar artery. In rare conditions, the PTA could be combined with others cerebrovascular anomalies, moyamoya disease (MMD) is one of them. CASE PRESENTATION: Here, we reported one rare case of MMD associated with PTA, the patient admitted to our department for severe dizziness and headache, imaging examination suggested MMD combined with right PTA, which arising from the ipsilateral cavernous portion of ICA. The patient received phased bilaterral revascularization with no any complication. In the subsequent follow-up, the patient's symptoms and intracranial vascular condition gradually improved. Moreover, we conducted a literature review of coexistence of PTA and MMD, the results of a web of science regarding such condition, and a deep discussion providing brief insight into the status of co-occurrence of PTA and MMD, including its manifestation, treatment and outcome. CONCLUSIONS: The coexistence of PTA and MMD was rarely reported, the pathogenesis of such condition remains unknown. We found that the features of the coexistence of PTA and MMD were diverse, revascularization might be a feasible for such patient.

Vertebral Artery Access Considerations in Coil Embolization of Small Superior Cerebellar Artery Aneurysm.

BACKGROUND: Coiling of small superior cerebellar artery aneurysms (sSCAAs) is challenging. We aimed to describe anatomic considerations in the vertebral and basilar artery (VA and BA) morphology for decision making in the coiling of sSCAAs. METHODS: Eleven patients with sSCAAs (<5 mm) treated at our institution between April 2015 and February 2022 were included to show our concept of deciding access routes in the coiling of sSCAAs. The access route was decided on the basis of VA characteristics, BA curvature, and aneurysm laterality. Adequate aneurysm occlusion on angiography (Raymond-Roy grading scale I and II), good outcome (modified Rankin Score 0-2) at the last follow-up, and adverse outcomes were evaluated. RESULTS: Simple coiling (n = 2), a balloon-assisted technique (n = 3), and stent-assisted technique (n = 6) were selected. At the last follow-up (median 13.0 months), adequate aneurysm occlusion and good outcome were obtained in all 9 patients (n = 10). Adverse outcomes were not observed. When VA dominance was equal, in the straight BA, the microcatheter insertion into the ipsilateral VA to the aneurysm was favorable to form a "fulcrum" on the contralateral side and obtain microcatheter stability. When an aneurysm was on the concave aspect of the curved BA, microcatheter insertion into the ipsilateral VA was favorable. As for the convex aspect's aneurysm location, the microcatheter insertion into the contralateral VA can be favored. Further, we described the VA origin classification as it relates to ease of access from a transradial approach. CONCLUSIONS: Vertebrobasilar morphology may be important in deciding access routes in the coiling of sSCAAs.

Anatomical Features of Posterior Cerebral Arteries and Basilar Artery in 170 Anatolian Fresh Cadavers: Implications for Surgical Planning and Intervention.

BACKGROUND: The posterior cerebral arteries (PCAs) are terminal branches of the basilar artery (BA) and are responsible for the primary supply of the occipital lobe. Saccular aneurysm is most commonly seen close to the bifurcation of the BA. Various surgical interventions are performed for aneurysms. Therefore, the anatomy and localization of the BA and PCA are crucial. The aim of this study was to determine the characteristics of these arteries in a large Anatolian population. METHODS: The study included 170 Anatolian fresh cadavers. The diameters of the BA and PCA were measured. Correlations according to sex and age groups were analyzed. The Q1, Q2, and Q3 angles between the right and left PCA, between the right PCA and BA, and between the left PCA and BA, respectively, were measured. The location of the PCA relative to the sulcus pontocruralis (pontocrural groove) was also evaluated. RESULTS: The diameter of the artery increased with age and was higher in males than in females. Q1 and Q2 diameters were larger in males, while the Q3 diameter was larger in females. The Q1 angle between the right and left PCAs was found to be higher in age range 40-59 years with a mean of 87.33 ± 17.91 mm. Finally, the bifurcation point of the PCA was most frequently located above the sulcus pontocruralis (pontocrural groove) and least frequently located on the sulcus pontocruralis (pontocrural groove). CONCLUSIONS: The findings of our study will contribute to the planning of surgical approaches, the development of endovascular devices, the success of invasive procedures, and the reduction of complications.

[Image Diagnosis of Trigeminal Neuralgia].

Classic trigeminal neuralgia is mainly caused by arterial compression; most cases involve the superior cerebellar artery, followed by the anterior cerebellar, basilar, and vertebral arteries. The detection of neurovascular conflicts in trigeminal neuralgia requires special magnetic resonance imaging(MRI)modalities, including high-resolution three-dimensional(3D)-T2 sequence, 3D-time of flight angiography, 3D-T1 sequencing with gadolinium injection, and merged images of these sequences. The conflicting sites are not necessarily restricted to the root entry zone of the trigeminal nerve root and can be located more distally, proximal to the Meckel's cavum. Arterial compression and its severity, including displacement, angulation, distortion, and atrophy of the trigeminal root, are good predictors of the long-term efficacy of decompression surgery. Veins, primarily the transverse pontine vein, comprise 10%-20% of all causative vessels in trigeminal neuralgia. Gadolinium-enhanced 3D-T1 MRI and high-resolution 3D-T2 MRI merged with computed tomographic angiography are useful for detecting venous compression.

[Microsurgical Procedures of Microvascular Decompression for Trigeminal Neuralgia].

Microvascular decompression for trigeminal neuralgia was successfully performed following the secure surgical steps. The most crucial step involves creating a safe operative field in the dural opening. The petrotentorial junction should be identified without cerebellar retraction before proceeding to the deeper areas. Dissecting the petrosal vein and opening the horizontal fissure contributed to the expansion of the operative field. Bleeding often occurs from the dorsal cerebellar bridging vein and junction of the petrosal vein into the superior petrosal sinus. Transposition of the most common offenders, the superior and anterior inferior cerebellar arteries, is effectively achieved by dissecting both the proximal and distal sides of the neurovascular compression site. Teflon should be placed at a sufficient distance to prevent contact with the nerve, which can lead to recurrence. Treating vertebrobasilar artery-related cases is challenging and involves the risk of cranial nerve injuries. Multiple offending vessels are commonly involved. In such cases, it is essential to be aware of the course of the trochlear and abducens nerves during decompression. Applying the most effective and least risky maneuver is necessary for treating cases involving the vertebrobasilar artery.