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A 54-year-old woman with no relevant medical history presented with severe headache, nausea, and vomiting for 8 days. Imaging examination revealed a subarachnoid hemorrhage in the left interpeduncular cistern without aneurysms. Computed tomography angiography and digital subtraction angiography found an anomalous vein near the site of the hemorrhagic clots, indicating abnormalities in cerebral venous drainage that provided an anastomosis between the drainage system of the deep middle cerebral, petrosal, and lateral mesencephalic veins. In the primitive pattern, the basal vein of Rosenthal drains into the lateral mesencephalic vein and to the petrosal sinus. This anomalous flow may predispose to subarachnoid hemorrhage, emphasizing the association between nonaneurysmal perimesencephalic hemorrhage and venous anomalies., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Trigeminal neuralgia (TN) due to venous compression is far less common than that due to arterial compression, and its pathogenesis is less clear. We investigated the clinical and imaging features of TN caused by solely venous compression by measuring the morphologies of the posterior cranial fossa (PCF) and the trigeminal nerve., Methods: We retrospectively reviewed records of TN patients who underwent microvascular decompression at our institution and extracted cases with solely arterial or solely venous compression. Preoperative magnetic resonance imaging was used to find the length (Y), width (X), height (Z), and volume (V) of the PCF, the angle between the trigeminal nerve and pons, and the distance between Meckel's cave and the root entry zone of the trigeminal nerve., Results: Of 152 patients, 24 had TN caused solely by venous compression. The value of Y was significantly smaller in the venous group than the arterial group (P < 0.01). The trigeminal nerve and pons was significantly smaller in the venous group (P < 0.01). We hypothesized that TN patients with solely venous compression had a characteristic PCF morphology with a short anteroposterior diameter (Y), such that age-related changes in brain morphology could alter the course of the trigeminal nerve and cause compression by a vein., Conclusions: The morphological features of the PCF differed between patients with TN of venous and those with TN of arterial etiology. Age-related changes in brain morphology and changes of course of the trigeminal nerve may also add to the possibility of developing TN, especially of venous etiology., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Developmental venous anomalies (DVAs) are the most common vascular malformation detected on intracranial cross-sectional imaging. They are generally benign lesions thought to drain normal parenchyma. Spontaneous hemorrhages attributed to DVAs are rare and should be ascribed to associated cerebral cavernous malformations, flow-related shunts, or venous outflow obstruction. Contrast-enhanced MRI, susceptibility-weighted imaging, and high-field MRI are ideal tools for visualizing vessel connectivity and associated lesions. DVAs are not generally considered targets for treatment. Preservation of DVAs is an established practice in the microsurgical or radiosurgical treatment of associated lesions., Competing Interests: Disclosure This study did not receive any funding or financial support. Dr B.A. Gross is a consultant for Medtronic, Stryker, and MicroVention., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: To improve postoperative outcome in middle third falcine meningiomas by cortical venous preservation., Background: Falcine meningiomas arise from the falx and do not involve the superior sagittal sinus (SSS). Their complete resection is often associated with the risk of venous infarction in the eloquent cortex due to overlying superficial cortical veins on the tumors., Method: We report one case of middle third falcine meningioma, where we used the posterior interhemispheric corridor for tumor approach., Conclusion: Use of the posterior interhemispheric approach, carefully raised bone flap, along with sharp dissection and vein reinforcement using fibrin glue can help to preserve the cortical veins while resecting the falcine meningiomas., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Rationale and Objectives: The purpose of this study was to determine the association between hemispheric synchrony in venous outflow at baseline and tissue fate after mechanical thrombectomy (MT) for acute ischemic stroke (AIS)., Materials and Methods: A two-center retrospective analysis involving AIS patients who underwent MT was performed. The four cortical veins of interest include the superficial middle cerebral vein (SMCV), sphenoparietal sinus (SS), vein of Labbé (VOL), and vein of Trolard (VOT). Baseline computed tomography perfusion data were used to compare the following outflow parameters between the hemispheres: first filling time (△FFT), time to peak (△TTP) and total filling time (△TFT). Synchronous venous outflow was defined as △FFT = 0. Multivariable regression analyses were performed to evaluate the association of venous outflow synchrony with penumbral salvage, infarct growth, and intracranial hemorrhage (ICH) after MT., Results: A total of 151 patients (71.4 ± 13.2 years, 65.6% women) were evaluated. Patients with synchronous SMCV outflow demonstrated significantly greater penumbral salvage (41.3 mL vs. 33.1 mL, P = 0.005) and lower infarct growth (9.0 mL vs. 14.4 mL, P = 0.015) compared to those with delayed SMCV outflow. Higher △FFT SMCV (β = -1.44, P = 0.013) and △TTP SMCV (β = -0.996, P = 0.003) significantly associated with lower penumbral salvage, while higher △FFT SMCV significantly associated with larger infarct growth (β = 1.09, P = 0.005) and increased risk of ICH (odds ratio [OR] = 1.519, P = 0.047)., Conclusion: Synchronous SMCV outflow is an independent predictor of favorable tissue outcome and low ICH risk, and thereby carries the potential as an auxiliary radiological marker aiding the treatment planning of AIS patients., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Isolated sinus dural arteriovenous fistulas (DAVFs) involve a dural sinus with occlusion on both sides of the diseased sinus segment. Because of venous drainage refluxing from the isolated sinus into the cortical veins, all isolated sinus DAVFs are Borden type III or Cognard type Ⅲ/Ⅳ. Venous drainage typically involves temporo-occipital cortical veins or the superior petrosal sinus and tributaries of the petrosal vein. However, drainage veins involving the perimedullary venous system are extremely rare. Here, we present a case of Cognard type V isolated sinus DAVF successfully treated with balloon catheter and Onyx., (Copyright © 2023. Published by Elsevier Inc.)

Objective: Mastery of sylvian fissure dissection is essential to access lesions within the deep basal cisterns. The deep sylvian vein and its tributaries play a major role during access to and beyond the carotid cistern through the sylvian fissure and determine the complexity of microdissection. Preserving the venous outflow during sylvian fissure dissection is the best reliable strategy to prevent postoperative venous strokes or venous hypertension. The authors report the role of the basal vein of Rosenthal (BVR) in the venous outflow pattern of the deep sylvian cistern., Methods: The authors analyzed 262 consecutive surgical cases involving sylvian fissure dissection from 2015 to 2017. Inclusion criteria were complete sylvian fissure dissection for the treatment of intracranial aneurysms. Exclusion criteria were giant size (aneurysm diameter > 24 mm), meningitis, subarachnoid hemorrhage within the sylvian cistern, absence of 4D CT angiography, and previous surgery. Retrospective radiological and operative video reviews were carried out to assess the association between the superficial sylvian vein and the BVR. The authors analyzed the course of the BVR and the patterns of venous drainage of the sylvian cistern. The surgical difficulty of sylvian fissure dissection was rated by the authors to study the operative significance of the venous patterns encountered. Two clinical cases are described to illustrate the proposed BVR classification., Results: A total of 97 patients met the selection criteria. The most frequent type of BVR was immature (diameter < 0.5 mm, 68%). When the BVR was incompletely developed or absent (immature type), the deep sylvian veins drained through a middle sylvian vein in 70% of cases, requiring advanced sylvian fissure dissection techniques. However, when the BVR was completely developed (32%), the middle sylvian vein was found in a minority of cases (6%), which allowed for an unobstructed transsylvian corridor. Interrater and test-retest reliability of the surgical difficulty was greater than 0.9., Conclusions: Preoperative assessment of the BVR anatomy is key to predict the deep sylvian venous pattern. The authors provide objective evidence supporting the reciprocal relationship between the type of BVR and the presence of a middle sylvian vein and the deep sylvian venous outflow. An immature BVR should alert the neurosurgeon of the high likelihood of finding a complex deep venous pattern, which may drive surgical planning.

In microvascular decompression surgery for trigeminal neuralgia, the veins are essential as an anatomical frame for the microsurgical approach and as an offending vessel to compress the trigeminal nerve. Thorough arachnoid dissection of the superior petrosal vein and its tributaries provides surgical corridors to the trigeminal nerve root and enables the mobilization of the bridging, brainstem, and deep cerebellar veins. It is necessary to protect the trigeminal nerve by coagulating and cutting the offending vein. We reviewed the clinical features of trigeminal neuralgia caused by venous decompression and its outcomes after microvascular decompression. Among patients with trigeminal neuralgia, 4%-14% have sole venous compression. Atypical or type 2 trigeminal neuralgia may occur in 60%-80% of cases of sole venous compression. Three-dimensional MR cisternography and CT venography can help in detecting the offending vein. The transverse pontine vein is the common offending vein. The surgical cure and recurrence rates of trigeminal neuralgia with venous compression are 64%-75% and 23%, respectively. Sole venous compression is a unique form of trigeminal neuralgia. Its clinical characteristics differ from those of trigeminal neuralgia caused by arterial compression. Surgical procedures to resolve venous compression include nuances in safely handling venous structures.

In the transsylvian (TS) approach, as characterized by clipping surgery, the presurgical visualization of the superficial middle cerebral vein (SMCV) can help change the surgical approach to ensure safe microsurgery. Nevertheless, identifying preoperatively the venous structures that are involved in this approach is difficult. In this study, we investigated the venous structures that are involved in the TS approach using three-dimensional (3D) rotational venography (3D-RV) and evaluated the effectiveness of this method for presurgical simulation. Patients who underwent 3D-RV between August 2018 and June 2020 were involved in this retrospective study. The 3D-RV and partial maximum intensity projection images with a thickness of 5 mm were computationally reconstructed. The venous structures were subdivided into the following three portions according to the anatomic location: superficial, intermediate, and basal portions. In the superficial portion, predominant frontosylvian veins were observed on 31 (41%) sides, predominant temporosylvian veins on seven (9%) sides, and equivalent fronto- and temporosylvian veins on 28 (37%) sides. The veins in the intermediate (deep middle cerebral and uncal veins) and basal portions (frontobasal bridging veins) emptied into the SMCV on 57 (75%) and 34 (45%) sides, respectively. The 3D-RV images were highly representative of the venous structures observed during microsurgery. In this study, 3D-RV was utilized to capture the details of the venous structures from the superficial to the deep portions. Presurgical simulation of the venous structures that are involved in the TS approach using 3D-RV may increase the safety of microsurgical approaches.

Background: Transsylvian approaches are a cornerstone of complex cranial operations, with wide applicability across cerebrovascular, skull base, and neuro-oncology operations. Deep lesions, especially those involving the basilar apex, midbrain, or interpeduncular fossa, require wide exposures that may be inhibited by the presence of a large complex of superficial sylvian veins (SSV) draining into the sphenoparietal sinus. This report describes technical and clinical aspects of the sphenoparietal sinus transposition (SPST) technique., Methods: Technical case report of the SPST technique, including a step-by-step neuroanatomic description, overview of common indications, clinical pearls and pitfalls, and illustrative case examples., Results: Once the benefits of proceeding with SPST have been established, the maneuver is initiated with 2 stepwise dural incisions: an incision from lateral to medial along the lateral margin of the lesser sphenoid wing, followed by an orthogonal cut across the temporal pole down the middle fossa floor. The pretemporal dura is peeled off the lateral wall of the cavernous sinus, allowing mobilization of the SSV complex and temporal pole posteriorly without disrupting or straining the connection point at the sphenoparietal sinus. Illustrative case examples include a clip reconstruction of a basilar apex aneurysm for which earlier endovascular treatment had failed and microsurgical resection of a peduncular cavernous malformation., Conclusions: SPST is a simple but versatile technique with important applications in complex cranial surgery. By mobilizing the SSV complex together with its dural attachment, the transsylvian corridor can be markedly widened, allowing access to the basilar apex region and ventral midbrain., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Vein of Galen malformation (VOGM) is an exceptionally uncommon form of congenital intracranial vascular malformations. It is highly unusual for this lesion to spontaneously thrombose. The clinical presentation of a patient may range from being asymptomatic to critically ill. The underlying pathophysiological mechanisms that cause spontaneous thrombosis are still poorly understood., Methods and Results: The literature on spontaneous thrombosis of VOGM was systematically reviewed, analyzed, and summarized with a focus on its pathophysiology, types, clinical presentations, diagnosis, management, and outcomes. It was also illustrated with a case presentation. The case presents an unusual presentation and location of a VOGM in a 2-year-old boy who was successfully treated with surgical resection., Conclusions: A handful of cases of thrombosed VOGM have been reported worldwide where surgery was used to treat the condition. Low-flow fistulas of the mural type are prone to spontaneous thrombosis, have delayed clinical presentations, and are typically diagnosed in young children. Among the many possible manifestations, hydrocephalus is by far the most common. In the absence of blood flow, MRI is the diagnostic test of choice. Depending on the patient's symptoms, surgery to either remove the aneurysm or divert the cerebrospinal fluid usually results in a good prognosis., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

During surgeries of the posterior cranial fossa, sacrificing the superior petrosal vein (SPV) can enhance visualization of the operative field but may also lead to postoperative venous infarction with potentially fatal consequences. We previously proposed that the safety of SPV sacrifice depends on whether there are collaterals that can take on the venous flow of the SPV after its sacrifice. Here, we propose several practical strategies that may be able to evaluate the presence of collaterals to the SPV, so that the safety of SPV sacrifice can be assessed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: The Uncal vein (UV), downstream of the deep middle cerebral vein (DMCV), has a similar drainage pattern to the superficial middle cerebral vein (SMCV) and may be involved in venous complications during the anterior transpetrosal approach (ATPA). However, in petroclival meningioma (PCM), where the ATPA is frequently used, there are no reports evaluating drainage patterns of the UV and the risk of venous complications associated with the UV during the ATPA., Methods: Forty-three patients with petroclival meningioma (PCM) and 20 with unruptured intracranial aneurysm (control group) were included. Preoperative digital subtraction angiography was used to evaluate UV and DMCV drainage patterns on the side of the tumor and bilaterally in patients with PCM and the control group, respectively., Results: In the control group, the DMCV drained to the UV, UV and BVR, and BVR in 24 (60.0%), eight (20.0%), and eight (20.0%) hemispheres, respectively. Conversely, the DMCV in the patients with PCM drained to the UV, UV and BVR, and BVR in 12 (27.9%), 19 (44.2%), and 12 (27.9%) patients, respectively. The DMCV was more likely to be drained to the BVR in the PCM group (p < 0.01). In three patients with PCM (7.0%), the DMCV drained only to the UV, and furthermore, the UV drained to the pterygoid plexus via the foramen ovale, posing a risk for venous complications during the ATPA., Conclusions: In the patients with PCM, the BVR functioned as a collateral venous pathway of the UV. Preoperative evaluation of the UV drainage patterns is recommended to reduce venous complications during the ATPA., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Objective: Opening the roof of the interhemispheric microsurgical corridor to access various neurooncological or neurovascular lesions can be demanding because of the multiple bridging veins that drain into the sinus with their highly variable, location-specific anatomy. The objective of this study was to propose a new classification system for these parasagittal bridging veins, which are herein described as being arranged in 3 configurations with 4 drainage routes., Methods: Twenty adult cadaveric heads (40 hemispheres) were examined. From this examination, the authors describe 3 types of configurations of the parasagittal bridging veins relative to specific anatomical landmarks (coronal suture, postcentral sulcus) and their drainage routes into the superior sagittal sinus, convexity dura, lacunae, and falx. They also quantify the relative incidence and extension of these anatomical variations and provide several preoperative, postoperative, and microneurosurgical clinical case study examples., Results: The authors describe 3 anatomical configurations for venous drainage, which improves on the 2 types that have been previously described. In type 1, a single vein joins; in type 2, 2 or more contiguous veins join; and in type 3, a venous complex joins at the same point. Anterior to the coronal suture, the most common configuration was type 1 dural drainage, occurring in 57% of hemispheres. Between the coronal suture and the postcentral sulcus, most veins (including 73% of superior anastomotic veins of Trolard) drain first into a venous lacuna, which are larger and more numerous in this region. Posterior to the postcentral sulcus, the most common drainage route was through the falx., Conclusions: The authors propose a systematic classification for the parasagittal venous network. Using anatomical landmarks, they define 3 venous configurations and 4 drainage routes. Analysis of these configurations with respect to surgical routes indicates 2 highly risky interhemispheric surgical fissure routes. The risks are attributable to the presence of large lacunae that receive multiple veins (type 2) or venous complex (type 3) configurations that negatively impact a surgeon's working space and degree of movement and thus are predisposed to inadvertent avulsions, bleeding, and venous thrombosis.

Background and Purpose: Cortical venous outflow has emerged as a robust measure of collateral blood flow in acute ischemic stroke. The addition of deep venous drainage to this assessment may provide valuable information to further guide the treatment of these patients., Materials and Methods: We performed a multicenter retrospective cohort study of patients with acute ischemic stroke treated by thrombectomy between January 2013 and January 2021. The internal cerebral veins were scored on a scale of 0-2. This metric was combined with existing cortical vein opacification scores to create a comprehensive venous outflow score from 0 to 8 and stratify patients as having favorable-versus-unfavorable comprehensive venous outflow. Outcome analyses were primarily conducted using the Mann-Whitney U and χ 2 tests., Results: Six hundred seventy-eight patients met the inclusion criteria. Three hundred fifteen were stratified as having favorable comprehensive venous outflow (mean age, 73 years; range, 62-81 years; 170 men), and 363, as having unfavorable comprehensive venous outflow (mean age, 77 years; range, 67-85 years; 154 men). There were significantly higher rates of functional independence (mRS 0-2; 194/296 versus 37/352, 66% versus 11%, P  < .001) and excellent reperfusion (TICI 2c/3; 166/313 versus 142/358, 53% versus 40%, P  < .001) in patients with favorable comprehensive venous outflow. There was a significant increase in the association of mRS with the comprehensive venous outflow score compared with the cortical vein opacification score (-0.74 versus -0.67, P = .006)., Conclusions: A favorable comprehensive venous profile is strongly associated with functional independence and excellent postthrombectomy reperfusion. Future studies should focus on patients with venous outflow status that is discrepant with the eventual outcome., (© 2023 by American Journal of Neuroradiology.)

Introduction: A vein of Galen aneurysmal malformation (VGAM) is a high-flow arteriovenous malformation that typically presents in early childhood. Complications associated with this condition include heart failure and hydrodynamic disorders resulting from high blood flow. Hydrocephalus is one of the hydrodynamic disorders. It can present in a chronic form due to a defect in the absorption of cerebrospinal fluid (CSF) resulting from venous hypertension or in an acute/subacute form due to obstruction of normal circulation routes caused by the mass effect of the VGAM. Currently, endovascular closure of the lesion is considered the treatment of choice. However, in acute/subacute presentations of obstructive hydrocephalus, progression may occur despite endovascular treatment, necessitating a cerebrospinal fluid diversion procedure. Prior to the advent of endoscopic treatment, ventricular shunts were utilized, but outcomes were poor due to the pathological hydrodynamic parameters associated with the malformation. The role of endoscopic third ventriculostomy as a treatment option in these situations remains unclear, and there is limited literature available. Therefore, we present the case of a patient with a vein of Galen aneurysmal malformation and obstructive hydrocephalus, which was treated via ETV. Furthermore, a literature review was conducted., Case Description: We present a 5-month-old infant who was diagnosed at birth with VGAM. At 2 months of age, a partial closure of the malformation was performed via endovascular. Subsequently, the patient presented at the emergency department with symptoms of irritability, lethargy, vomiting, feeding refusal, and "setting sun" sign of several days' duration due to obstructive hydrocephalus. The patient was successfully treated via ETV. Following this, a new arteriography was performed and revealed occlusion of the VGAM. The child clinically improved and currently exhibits mild psychomotor impairment after 1-year follow-up., Conclusion: In the literature, there are a limited number of reports on the treatment of obstructive hydrocephalus associated with VGAM via ETV. These reports have demonstrated good outcomes with minimal surgical complications. Our patient also exhibited good results. As such, ETV is a viable and safe option for the treatment of obstructive hydrocephalus associated with VGAM in pediatric patients. However, more research is needed to establish the effectiveness of ETV in comparison to other treatment options and to understand the long-term outcomes., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Anatomical studies of the tentorial sinuses (TS) are scant, and to our knowledge, histological studies of this structure have not been reported. Therefore, we aim to better elucidate this anatomy., Methods: In 15 fresh frozen, latex injected, adult cadaveric specimens, the TS were evaluated with microsurgical dissection and histology., Results: The superior layer had a mean thickness of 0.22 mm, and the inferior layer had a mean thickness of 0.26 mm. Two types of TS were identified. Type 1 was a small intrinsic plexiform sinus with no obvious connections to the draining veins with gross examination. Type 2 was a larger tentorial sinus with direct connections to the bridging veins from the cerebral and cerebellar hemispheres. In general, type 1 sinuses were located more medially than type 2 sinuses. The inferior tentorial bridging veins drained directly into the TS along with connections to the straight and transverse sinuses. In 53.3% of specimens, superficial and deep sinuses were seen, with superior and inferior groups draining the cerebrum and cerebellum, respectively., Conclusions: We identified novel findings for the TS which can be considered surgically and when diagnosing pathology involves these venous sinuses., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: A dural arteriovenous fistula involving the superior petrosal vein (SPV DAVF) is an extremely rare condition. Therefore, its clinical presentation, imaging characteristics, treatment methods, and risk factors remain unclear. In this study, we discuss and analyze the aforementioned features of an SPV DAVF., Methods: We retrospectively reviewed 30 patients with SPV DAVFs, with a 1-year follow-up rate of 96.67% (29 of 30). The neurological function of the patients was assessed using the modified Aminoff-Logue scale and the modified Rankin Scale score. The risk factors before and after treatment were established using univariate and multivariate logistic regression analyses. Additionally, treatments involving 3 distinct SPV DAVF drainage patterns were presented., Results: Of the 30 patients, 24 were men (80.0%). Besides, the angiography images were reexamined 12 months after surgery. Univariate analyses indicated that the extent of edema (odds ratio 1.889, 95% confidence interval 1.132-3.154) and the number of draining veins (≤2) (odds ratio 10.833, 95% confidence interval 1.961-59.834) were risk factors for pretreatment modified Rankin Scale score ≥3. However, multivariate analyses revealed no statistically significant differences (P = 0.051, P = 0.055). Following the multivariate analyses, steroid pulse (odds ratio 12.153 95% confidence interval 1.080-136.772) was found to be the only significant risk factor for post-treatment difference between pretreatment and 1-year follow-up modified Rankin Scale score ≥2., Conclusions: A DAVF with SPV drainage is an uncommon type of intracranial vascular malformation. Most lesions involve the brain stem or high cervical spinal cord, thereby posing a higher risk of disability or death. Moreover, neuronal damage from persistent venous hypertension is permanent. Therefore, precise diagnosis and timely treatment are key to a good patient prognosis., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The preoperative assessment of cerebral veins is important to avoid unexpected cerebral venous infarction in the neurosurgical setting. However, information is particularly limited regarding deep Sylvian veins, which occasionally disturb surgical procedures for cerebral anterior circulation aneurysms. The predictability of detecting deep Sylvian veins and their tributaries using a modern multimodal fusion image was aimed to be evaluated. Moreover, 51 patients who underwent microsurgery for unruptured cerebral aneurysms with Sylvian fissure dissection were retrospectively reviewed. The visualization of the four components of the deep Sylvian veins in conventional computed tomography (CT) venography and multimodal fusion images was evaluated. To compare the detection accuracy among these radiological images, the sensitivity and specificity for the detection of each of the four venous structures were calculated in comparison with those of intraoperative inspections. The kappa coefficients were also measured and the inter-rater agreement for each venous structure in each radiological image was examined. In all veins, the multimodal fusion image exhibited a high detection rate without statistical difference from intraoperative inspections (P = 1.0). However, CT venography exhibited a low detection rate with a significant difference from intraoperative inspections in the common vertical trunk (P = 0.006) and attached vein (P = 0.008). The kappa coefficients of the fusion image ranged from 0.73 to 0.91 and were superior to those of CT venography for all venous structures. This is the first report to indicate the usefulness of a multimodal fusion image in evaluating deep Sylvian veins, especially for the detection of nontypical, relatively small veins with large individual variability.

Introduction: Vein of Galen aneurysmal malformations (VGAMs) can, through multiple mechanisms, complicate with hydrocephalus (HCP). It is generally agreed that management strategies in this scenario should focus on endovascular embolizations. Treatment options for non-responders, however, have been only scarcely reported upon., Case Presentation: We present a nine-month-old boy with a mural type VGAM complicated by HCP. Despite endovascular occlusion of the sole feeder, the child exhibited hydrocephalus progression prompting an Endoscopic Third Ventriculostomy (ETV). This procedure restored a cerebrospinal fluid (CSF) circulation otherwise impaired by aqueduct obstruction. Later, a new feeder arose and a second embolization was ultimately needed in order to achieve VGAM regression. Throughout four years of follow up, the child attained all developmental marks., Discussion/conclusion: VGAMs are prone to hydrocephalus development as there is both an underlying venous congestion and a mechanical, obstructive component. Although there is a rationale for addressing both components, the underlying AV shunts and subsequent venous pressure elevations usually determine failure of traditional CSF shunting strategies. It is therefore challenging to manage HCP in patients who failed to improve following endovascular embolizations. For such cases, ETV stands as an elegant minimal invasive alternative with potential to provide a more physiologic drainage route and thus better allow for neurological development., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Background: Microvascular decompression for trigeminal neuralgia (TN) may require sacrifice of the superior petrosal vein (SPV), with potential risks of ischemia and hemorrhagic complications due to impaired venous return., Objective: To investigate methods for safely sacrificing the SPV., Methods: We retrospectively reviewed 21 cases in 346 consecutive microvascular decompression surgeries for TN. They were intraoperatively identified as SPV and its tributaries being the offending vessels causing TN and were intentionally sacrificed., Results: The transverse pontine vein (TPV) was sacrificed in 10 patients. The main trunk of the SPV was sacrificed using the TPV as a collateral flow pathway in 10 patients. No complications occurred related to impaired venous return., Conclusion: The venous flow conversion technique can be applied to safely sacrificing the SPV and its tributaries with the TPV acting as a collateral blood flow pathway to prevent postoperative impaired venous return., (Copyright © The Author(s) 2022. Published by Wolters Kluwer Health, Inc. on behalf of Congress of Neurological Surgeons.)

Recent studies (Alaou-Ismaili et al. 2020; Kilic et al. Eur J Radiol 56:212-219, 2005) among experienced sub-specialized neurosurgeons described divergent perceptions of surgical risk for venous sacrifice in posterior fossa surgery. Three galenic veins stood out as controversial in venous risk assessment and underexplored in the literature: the internal occipital vein (IOV), the precentral cerebellar vein (PCV), and the superior vermian vein (SVV). We have conducted a narrative review based on a systematic literature search to analyze terminology and anatomic descriptions and to suggest a coherent synthesis of published data on these veins. A systematic PubMed literature search was carried out using the keywords: "posterior fossa," "venous anatomy," and "radiology." Relevant radiological, microsurgical, and anatomical articles were selected if they described the anatomy of the three veins. Anatomical descriptions were analyzed with hermeneutic methodology alongside the articles' radiological and anatomical dissection pictures. New illustrations were created to depict the synthesized image of the venous anatomy. A total of 13 articles described the anatomy and terminology of the relevant veins. The descriptions of the IOV included smaller non-occipital vessels that confused the identification of the vessel. IOV is analyzed to be the vein draining the primary visual cortex, which drains into the vein of Galen (VG). The PCV and SVV enter the VG from below and are fused in almost half of all studied patients, creating a third vessel by the name of the superior cerebellar vein. A conscientious narrative review and hermeneutic analysis produced a synthesized, uniform picture of terminology and anatomy. Consensus on anatomical descriptions and definitions are indispensable for validation of anatomy, research into anatomical variation, for surgical planning and documentation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The transsylvian approach is a versatile treatment method for aneurysms of the anterior circulatory system. Studies have shown that sylvian veins run in various patterns, suggesting the need for dissection between veins to obtain appropriate surgical corridor. In case of inadvertent sylvian vein injury, serious complications such as venous congestion may occur., Method: We herein describe the "side-to-side anastomosis reconstruction technique" of the resected superficial sylvian vein., Conclusion: This technique can be effective for the reconstruction of other cortical veins, and indocyanine green videoangiography was effective in determining the indications for venous reconstruction., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

(1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal-petrosal-mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé's vein, as detected on the CTAs, is proposed here (types 0-3).

Background: Endovascular thrombectomy (EVT) in large vessel occlusion (LVO) in anterior circulation acute ischaemic stroke (AIS) results in good functional outcomes in only approximately 60% of the patients. Internal cerebral veins (ICVs) are easily visible, with a consistent midline location, and are linked to stroke outcomes. We hypothesize that ICV asymmetry on multiphasic CT angiogram (mCTA) can be an adjunctive predictor for poor functional outcomes., Methods: We studied consecutive AIS patients from 2017 to 2019 with anterior circulation LVO treated with EVT regardless of intravenous thrombolysis. Asymmetrical ICV was defined as the presence of hypodensity (less opacification) on the ipsilateral occlusion side as compared with the contralateral side. The primary outcome was modified Rankin Score (mRS) score at 3 months. Secondary outcomes were good recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3), symptomatic hemorrhage, and mortality., Results: A total of 185 patients were included with a median age of 70 years (IQR 59-77); 87 patients (47%) were female. 82 patients (44.3%) achieved good functional outcomes (mRS 0-2) at 3 months. On multivariate analysis, National Institutes of Health Stroke Scale (NIHSS) (OR 1.076, 95% CI 1.015 to 1.140; p<0.013), poor collateral score (OR 0.285, 95% CI 0.162 to 0.501; p<0.001), asymmetrical ICV on the peak venous phase (OR 2.47, 95% CI 1.115 to 5.471; p<0.026), and late venous phase of the mCTA (OR 2.642, 95% CI 1.161 to 6.016; p<0.021) were independent risks factors of poor outcomes., Conclusion: ICV asymmetry is a novel radiological sign which is independently associated with poor functional outcomes in EVT, even after correction for collateral circulation. Further studies are needed to validate this finding., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Cerebral venous sinus thrombosis is rare and might be overlooked by healthcare providers. It often occurs in the transverse sinuses, superior sagittal sinus, and the vein of Trolard. Sphenoparietal sinus (SPS) and/or superficial middle cerebral vein (SMCV) thrombosis is rare and only 12 cases reported in the literature., Case Description: We report a 47-year-old woman with iron deficiency anemia associated with myoma uteri who developed left SPS and SMCV thrombosis. She presented with sudden unconsciousness, right hemiplegia, and aphasia. Brain computed tomography showed subcortical hemorrhages in the left frontal and temporal lobes. Magnetic resonance imaging did not reveal the cause of the bleeding. Although antihypertensive treatment with nicardipine was initiated, she deteriorated into coma the next day and underwent emergency decompressive craniectomy. Thrombosis of the SMCV was identified during surgery. Re-examination of preoperative T2 star-weighted imaging revealed thrombosis of the SPS and SMCV., Conclusion: All but one of the reviewed cases had the thrombosis develop on the left side, which may be attributed to anatomical and brain functional laterality. When an edematous change or cortical hemorrhage of unknown cause is encountered within the perisylvian region, especially on the left side, the possibility of SPS and SMCV thrombosis should be considered., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Objective: In microvascular decompression (MVD) surgery through the retrosigmoid approach, the surgeon may have to sacrifice the superior petrosal vein (SPV). However, this is a controversial maneuver. To date, high-level evidence comparing the operative outcomes of patients who underwent MVD with and without SPV sacrifice is lacking. Therefore, this study sought to bridge this gap., Methods: The authors searched the Medline and PubMed databases with appropriate Medical Subject Heading (MeSH) terms and keywords. The primary outcome was vascular-related complications; secondary outcomes were new neurological deficit, cerebrospinal fluid (CSF) leak, and neuralgia relief. The pooled proportions of outcomes and OR (95% CI) for categorical data were calculated by using the logit transformation and Mantel-Haenszel methods, respectively., Results: Six studies yielding 1143 patients were included, of which 618 patients had their SPV sacrificed. The pooled proportion (95% CI) values were 3.82 (0.87-15.17) for vascular-related complications, 3.64 (1.0-12.42) for new neurological deficits, 2.85 (1.21-6.58) for CSF leaks, and 88.90 (84.90-91.94) for neuralgia relief. The meta-analysis concluded that, whether the surgeon sacrificed or preserved the SPV, the odds were similar for vascular-related complications (2.5% vs 1.5%, OR [95% CI] 1.01 [0.33-3.09], p = 0.99), new neurological deficits (1.2% vs 2.8%, OR [95% CI] 0.55 [0.18-1.66], p = 0.29), CSF leak (3.1% vs 2.1%, OR [95% CI] 1.16 [0.46-2.94], p = 0.75), and neuralgia relief (86.6% vs 87%, OR [95% CI] 0.96 [0.62-1.49], p = 0.84)., Conclusions: SPV sacrifice is as safe as SPV preservation. The authors recommend intentional SPV sacrifice when gentle retraction fails to enhance surgical field visualization and if the surgeon encounters SPV-related neurovascular conflict and/or anticipates impeding SPV-related bleeding.

Competing Interests: None

In this third review article on the endovascular management of intracranial dural AVFs, we discuss transvenous embolization approaches. Transvenous embolization is increasingly popular and now the first-line approach for ventral dural AVFs involving the cavernous sinus and hypoglossal canal. In addition, transvenous embolization is increasingly used in lateral epidural dural AVFs in high-risk locations such as the petrous and ethmoid regions. The advantage of transvenous embolization in these locations is the ability to retrogradely embolize the draining vein and fistula while reducing the risk of ischemic cranial neuropathy or brain parenchymal infarction commonly feared from a transarterial approach. By means of coils ± ethylene-vinyl alcohol copolymer, transvenous embolization can achieve angiographic cure rates of 80%-90% in ventral locations. Potential complications include transient cranial neuropathy, neurologic deterioration due to venous outflow obstruction, and perforation while navigating pial veins. Transvenous embolization should be considered when dural AVFs arise in proximity to the vasa nervosum or extracranial-intracranial anastomoses., (© 2022 by American Journal of Neuroradiology.)

Objectives: The risks and benefits of coagulating intradural venous elements during a retrosigmoid approach for trigeminal neurovascular decompression has not been accurately established. The objectives of this study were to identify the veins that drain into the superior petrosal sinus, classify them in relation to the suprameatal tubercle, and determine the implication of their coagulation., Methods: A retrospective study of 3-dimensional surgical videos of retrosigmoid approaches for trigeminal neurovascular decompression from the Laboratory of Neurosurgical Innovations of Tucumán (LINT) digital archive was carried out. The veins encountered were classified into 3 groups: retromeatal, meatal and premeatal. The neurosurgical postoperative complication scale proposed by Landriel et al. was utilized to assess complications from venous coagulation. A grade 0 was added for patients without complications. The STATA 14 program was utilized for statistical analysis., Results: The pontocerebellar-petrosal veins of 28 patients who underwent trigeminal decompressive surgery were analyzed. In 7 cases these were found in the retromeatal region; 100% were sacrificed. Eleven cases revealed veins within the meatal region; 90.91% were coagulated. Veins in the premeatal region were found in 14 cases; 57.14% were sacrificed. In the postoperative follow-up, 27 patients were grade 0 and 1 patient developed postoperative meningitis (grade Ib complication). No patient suffered vascular complications., Conclusions: The venous elements identified in trigeminal neurovascular decompressive surgery are variable. We propose classifying them into retromeatal, meatal, and premeatal groups. Retromeatal and meatal veins can be safely sacrificed for appropriate visualization of the neurovascular conflict. The premeatal venous elements should be coagulated only in justified cases., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Trigeminal neuralgia (TN) is often caused by various vein forms. Herein, we report two cases of vein-related TN. In the first case, the vein of the cerebellopontine fissure (VCPF), along with the thickened surrounding arachnoid, clung to the trigeminal nerve. As the perfusion range of this vein was expected to be wide and its injury might cause extensive venous infarction, the anchor between the trigeminal nerve and the vein was carefully dissected and the vein was successfully transposed. In the second case, the involvement of the vein of the middle cerebellar peduncle (VMCP), which penetrates the nerve bundle of the trigeminal nerve, was suspected. Because vein transposition was impossible, the vein was transected at the nerve penetration site after confirming that there was sufficient collateral venous outflow. The superior petrosal vein and its tributaries are the primary causative veins of vein-related TN, and their contact patterns are infinite. Moreover, their perfusion range and the presence or absence of collateral venous outflow vary from case to case. Therefore, it is necessary to judge the perfusion range as well as collateral venous outflow based on preoperative images and intraoperative findings and to determine the appropriate treatment method for each case.

Background: Intraoperative intracranial pressure (ICP) control continues to be a challenge for anaesthetists during craniotomies. Although many standard brain-dehydrating protocols are available, they may be ineffective in certain surgical situations and may result in harm either to the systemic or cerebral circulation. Sphenopalatine ganglion block (SPGB) can reverse the vasodilatory effects of anaesthesia during craniotomy., Methods: This prospective randomised study was carried from June 2020 to February 2021. Fifty-two patients were randomly allocated into two groups, the block group (B) and the non-block control group (Non). Twenty-six patients were enrolled in the (B) group and received a bilateral transnasal SPG block with 2% lidocaine using a hallow culture swab prior to anaesthesia induction. Intraoperative monitoring was performed using standard American Society of Anesthesiologists (ASA) monitors in addition to invasive monitoring using intra-arterial cannulas and jugular venous bulb catheters. Subdural ICP monitors were also employed. The arterio-jugular oxygen difference in mmol/l (AjvDO2) was then calculated. Mean flow velocity cm/s (MFV) and pulsatility index (PI) were monitored in both groups using Transcranial Doppler. Haemodynamic data were recorded every 30 min from induction of anaesthesia until the closure of the dura., Results: There was a significant difference in ICP prior to the dural opening between the block group (B), mean ± sd 7.58 ± 1.47, and the non-block group (Non), mean ± sd (11.69 ± 1.72), p-value < 0.001. There was no significant difference in MFV between (B) group, mean ± sd 72.65 ± 2.28 and (Non) group, mean ± sd 71.19 ± 3.09 before intubation (baseline values). While there was a significant difference after intubation between block group, mean ± sd 72.12 ± 1.77 and non-block group, mean ± sd 74.62 ± 5.07, p-value = 0.02. There was an insignificant difference between (B) and (Non) groups before intubation regarding PI values, while PI was significantly higher in (B) group than the (Non) group after intubation where mean ± sd was 1.17 ± 0.05 versus 0.96 ± 0.09, respectively, p-value = 0.001. There was no significant difference regarding cerebral oxygenation between the groups., Conclusions: SPGB can control factors that increase CBF during anaesthesia by the block of parasympathetic vasodilatory fibres to the arterial system in the anterior cerebral circulation, while neither hindering cerebral venous drainage nor impairing cerebral oxygenation, as it gives no supply to cerebral veins and does not affect basal CBF. Additionally, it does not affect systemic circulation., (Copyright © 2021 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.)

Background: Surgical planning for treating brain arteriovenous malformations (bAVMs) is challenging because it entails visualizing 3-dimensional (3D) relationships between the nidus, its feeding and en passage arteries, and draining veins. Surgical experience in developing the capacity to mentally visualize pathological bAVM angioarchitecture could be complemented by this software, and thus potentially lower the steep learning curve for understanding complex bAVM angioarchitecture. We evaluated the clinical application of freely available online 3D reconstruction software in facilitating visualization of AVM angioarchitecture for presurgical planning., Methods: Preoperative Digital Imaging and Communications in Medicine magnetic resonance imaging/magnetic resonance angiography images of 56 superficial bAVMs from 2013 to 2018 were processed using open-source software Horos. 3D rendered images were compared with the surgical view to evaluate software accuracy and determine its value as a preoperative tool. 3D reconstructed images were compared with intraoperative recordings., Results: A useful image identifying both the main feeding artery and draining vein was achieved in 35 of 56 cases (62.5%). Reconstructions of small AVMs (nidus ≤2 cm) and those located within the temporal or cerebellar cortex were less useful due to soft tissue artifacts. Frontal and parietal lobe lesions had significantly higher rates of identifying feeding arteries and draining veins (P < 0.05)., Conclusion: Presurgical planning for resection of superficial bAVMs using Horos software allows for a comprehensive 3D analysis of the bAVM angioarchitecture. This technique is most useful for frontal and parietal lobe lesions, and aids the surgeon in formulating an optimal surgical strategy. The 3D reconstruction of the brain surface offers a surgical map not influenced by brain shift., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The superficial middle cerebral vein (SMCV) is one of the main factors that can impede a wide opening of the sylvian fissure. To reveal the most efficient SMCV dissection for a wide operative field while preserving the veins in the trans-sylvian approach, we retrospectively investigated the SMCVs through intraoperative video images. We characterized the SMCV as composed of the frontosylvian trunk (FST; receiving frontosylvian veins [FSVs] or parietosylvian veins [PSVs]), the temporosylvian trunk (TST; receiving temporosylvian veins [TSVs]), and the superficial middle cerebral common trunk (SMCCT; receiving both FSV/PSV and TSV), and classified the SMCVs of the 116 patients into 5 types based on the morphological classification of the SMCV. Type A SMCV (60.4%) with the SMCCT anastomosed to the frontal side had few bridging veins (BVs) between the SMCCT and the temporal side during dissection. Type B (7.8%) had the SMCCT with no anastomoses to the frontal side. In Type C (17.2%) consisting of the FST and TST and Type D (12.9%) with a merging of the vein of Trolard and Labbé posteriorly and the SMCVs dividing into the FST and the TST again proximally, there were few BVs between the FST and the TST during dissection. Finally, in Type E (1.7%) showing an undeveloped SMCV, there were no BVs between the frontal and the temporal lobes. Postoperative venous infarction occurred in 2.6%. Morphological classification of the SMCV can inform appropriate dissection line to create a wide operative field while preserving the veins in the trans-sylvian approach.

Background: High-positioned and/or superoposteriorly directed anterior communicating artery aneurysms can be treated by direct clipping using the pterional (fronto-temporo-sphenoidal) approach. This procedure, however, requires stronger retraction of the frontal lobe. Hence, preservation of the prominent frontal bridging veins (FBVs) draining into the sphenoparietal sinus (SPS) remains a significant challenge in preventing postoperative venous congestion., Methods: We developed a technique to release the tension on the FBVs by pulling them together with the SPS epidurally. In 2 patients, who had presented with high-positioned and/or superoposteriorly directed anterior communicating artery aneurysms, we peeled off the arachnoid surrounding the FBVs and detached it from the brain surface. We further released the veins by moving them posteriorly, together with the SPS epidurally., Results: Using this technique, we established a wide corridor through a more lateral transsylvian trajectory with effective posterior retraction of the frontal lobe and were successful in clipping and obliterating the aneurysms., Conclusions: Open clipping of unruptured intracranial aneurysms requires accuracy to preserve higher brain function. Our technique was successful in both patients, and preserving the FBVs could be useful in the treatment of such aneurysms., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Preserving cortical frontal bridging veins draining into the superior sagittal sinus is a factor of good neurological outcome in anterior interhemispheric transcallosal approaches, classically performed to reach intraventricular tumors. Challenging the idea that veins are utterly variable, we propose a statistical analysis of 100 selective cerebral angiographies to determine where to place the craniotomy in order to expose the most probable vein-free area. The mean distance to the first pre-coronal vein was 6.66 cm (± 1.73, 1.80 to 13.00) and to the first post-coronal vein 0.94 cm (± 0.92, 0 to 3.00) (p < 0.001). The probability of absence of bridging veins was 92.0% at 4 cm anterior to the coronal suture versus 37.5% at 1 cm and 12.5% at 2 cm posteriorly. The length of the surgical corridor (distance between the first pre-coronal and post-coronal vein) was 7.60 cm (± 1.72, 3.00 to 14.10). Overall, the ideal centering point of the craniotomy was 2.86 cm (± 1.08, - 0.65 to 6.50) ahead of the coronal suture. The mean number of veins within 6 cm behind the coronal suture was 8.47 (± 2.11, from 3 to 15) versus 0.530 (± 0.82, from 0 to 3) ahead of the coronal suture (p < 0.001). These findings support a purely pre-coronal 5 cm craniotomy for interhemispheric approaches., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)