Cerebellar Veins Research Articles

Complete removal of a cavernous malformation in the dorsal pons, in contact with the expanded transpontine vein: illustrative case.

Craniotomy is required for the removal of brainstem cavernous malformations (CMs) with repeated hemorrhage, and this condition is often complicated by an accompanying developmental venous anomaly (DVA). However, a DVA of the brainstem or cerebellum with drainage penetrating the pons is an exceptional finding. A 57-year-old man presented with double vision. Computed tomography revealed progressive enlargement of the hemorrhage in the dorsal pons. Contrast-enhanced magnetic resonance angiography revealed an expanded transverse vessel penetrating the center of the pons in contact with the CM. Digital subtraction angiography revealed that the DVA, comprising the expanded transpontine vein and some cerebellar medullary veins acting as normal venous drainage, coexisted with the CM. By utilizing the angioarchitecture and intraoperative neuronavigation system data, electrophysiological mapping, and indocyanine green videoangiography, complete removal of the CM was accomplished while preserving the DVA and brain function. This study presents the intraoperative images of an expanded transpontine vein as a DVA, which has never been depicted in a live patient before, accompanied by a CM in the dorsal portion of the pons. https://thejns.org/doi/10.3171/CASE24314.

Microsurgical Resection of a Pediatric Tegmentum Tumor Through the Paramedian Supracerebellar Transtentorial Approach With the Tentorial Cut Technique: 2-Dimensional Operative Video.

The brainstem contains a highly complex group of nuclei and major white matter tracts within a small volume.1 The complex nature of its anatomy creates challenges for surgery in this area, impeding the standardization of approaches. Therefore, the concept of the "safe entry zone" should be considered with caution, and the strategy for each patient should be tailored based on the relevant subunit of the brainstem and individual patient characteristics. The critical parameter to target in patients is achieving the highest possible extent of resection while preserving function.1 The paramedian supracerebellar transtentorial approach is usually suitable for midbrain lesions. This approach allows for targeting tegmental tumors through the posterolateral midbrain surface.1 It is typically performed through a paramedian suboccipital craniotomy, ideally with the patient in the semisitting position, and is now considered a standard and safe approach.2 In patients with a spontaneous atrial right-to-left shunt, lateral or semilateral positions are viable alternatives, with the semilateral preferred for intraoperative magnetic resonance imaging.1 The cerebellar hemispheric tentorial bridging veins are usually located in the surgical route, narrowing the surgical corridor.3 Sacrifice or unintended rupture of these veins can sometimes lead to unexpected serious complications. Therefore, it is essential to preserve these veins during supracerebellar approaches.3 In this study, we demonstrate the resection of a pediatric tegmentum tumor through the left-sided paramedian supracerebellar transtentorial approach. In addition, we show the tentorial cut technique used to preserve the cerebellar hemispheric tentorial bridging veins. The patient's parents consented to the procedure and to the publication of his image.

Infragalenic triangle as a gateway to dorsal midbrain and posteromedial thalamic lesions: descriptive and quantitative analysis of microsurgical anatomy.

Anatomical triangles provide neurosurgeons with the specificity required to access deep targets, supplementing more general instructions, such as craniotomy and approach. The infragalenic triangle (IGT), bordered by the basal vein of Rosenthal (BVR), precentral cerebellar vein (PCV), and the quadrangular lobule of the cerebellum, is one of a system of anatomical triangles recently introduced to guide dissection to brainstem cavernous malformations and has not been described in detail. This study aimed to quantitatively analyze the anatomical parameters of the IGT and present key nuances for its microsurgical use. A midline supracerebellar infratentorial (SCIT) approach through a torcular craniotomy was performed on 5 cadaveric heads, and the IGT was identified in each specimen bilaterally. Anatomical measurements were obtained with point coordinates collected using neuronavigation. Three cadaveric brains were used to illustrate relevant brainstem anatomy, and 3D virtual modeling was used to simulate various perspectives of the IGT through different approach angles. In addition, 2 illustrative surgical cases are presented. The longest edge of the IGT was the lateral edge formed by the BVR (mean ± SD length 19.1 ± 2.3 mm), and the shortest edge was the medial edge formed by the PCV (13.9 ± 3.6 mm). The mean surface area of the IGT was 110 ± 34.2 mm2 in the standard exposure. Full expansion of all 3 edges (arachnoid dissection, mobilization, and retraction) resulted in a mean area of 226.0 ± 48.8 mm2 and a 2.5-times increase in surface area exposure of deep structures (e.g., brainstem and thalamus). Thus, almost the entire tectal plate and its relevant safe entry zones can be exposed through an expanded unilateral IGT except for the contralateral inferior colliculus, access to which is usually hindered by PCV tributaries. Exposure of bilateral IGTs may be required to resect larger midline lesions to increase surgical maneuverability or to access the contralateral pulvinar. The IGT provides a safe access route to the dorsal midbrain and reliable intraoperative guidance in the deep and complex anatomy of the posterior tentorial incisura. Its potential for expansion makes it a versatile anatomical corridor not only for intrinsic brainstem lesions but also for tumors and vascular malformations of the pineal region, dorsal midbrain, and posteromedial thalamus.

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.

Preserving the cerebellar hemispheric tentorial bridging veins through a novel tentorial cut technique for supracerebellar approaches.

The objective of this study was to describe the distribution pattern of cerebellar hemispheric tentorial bridging (CHTB) veins on the tentorial surface in a case series of perimedian or paramedian supracerebellar approaches and to describe a novel technique to preserve these veins. A series of 141 patients with various pathological processes in different locations was operated on via perimedian or paramedian supracerebellar approaches by the senior author from July 2006 through October 2022 and was retrospectively evaluated. During surgery, the number and locations of all CHTB veins were recorded to establish a distribution map on the tentorial surface, divided into nine zones. Patients were classified into four groups according to the surgical technique used to manage CHTB veins: 1) group 1 consisted of CHTB veins preserved without intervention during surgery or no CHTB veins found in the surgical route; 2) group 2 included CHTB veins coagulated during surgery; 3) group 3 included CHTB veins preserved with arachnoid and/or tentorial dissection from the cerebellar or tentorial surface, respectively; and 4) group 4 comprised CHTB veins preserved using a novel tentorial cut technique. Overall, 141 patients were included in the study. Of these 141 patients, 38 were in group 1 (27%), 32 in group 2 (22.7%), 47 in group 3 (33.3%), and 24 in group 4 (17%). The total number of CHTB veins encountered was 207 during surgeries on one side. According to the distribution zones of the tentorium, zone 5 had the highest density of CHTB veins, while zone 7 had the lowest. Of the patients in group 4, 6 underwent the perimedian supracerebellar approach and 18 had the paramedian supracerebellar approach. There were 39 CHTB veins on the surface of the 24 cerebellar hemispheres in group 4. The tentorial cut technique was performed for 27 of 39 CHTB veins. Twelve veins were not addressed because they did not present any obstacles during approaches. During surgery, no complications were observed due to the tentorial cut technique. Because there is no way to determine whether a CHTB vein can be sacrificed without complications, it is important to protect these veins in supracerebellar approaches. This new tentorial cut technique in perimedian or paramedian supracerebellar approaches makes it possible to preserve CHTB veins encountered during supracerebellar surgeries.

Cognard Type Ⅴ Torcular Dural Arteriovenous Fistula: A Rare Entity

Tentorial dural arteriovenous fistulas (DAVFs) are a dangerous subtype of fistula. Lawton etal classified this type of fistula into 6 categories based on specific operative strategies. Clinical manifestations of 6 types of tentorial DAVFs vary to some extent. Cognard type V DAVFs in the tentorial region are usually petrosal/superior petrosal sinus DAVFs. DAVFs with perimedullary venous drainage around the torcular herophili are rare. The veins of the posterior fossa are intricate and variable. There are anatomic communications between the perimedullary vein and cerebellar vein or veins of the brainstem. Almost all of the Cognard type V DAVFs are found in the posterior fossa. Here, we present a Cognard type V DAVF with a fistula located around the torcular herophili.

Interposition and transposition techniques of vascular decompression for hemifacial spasm

To analyze the vessels compressing facial nerve root exit zone and efficacy of interposition and transposition techniques of vascular decompression for hemifacial spasm. Vascular compression was evaluated in 110 patients. Implant interposition between vessels and nerve was performed in 52 cases, transposition of arteries without contact between implants and nerve - in 58 patients. Compressing vessels were anterior (44), posterior (61) inferior cerebellar, vertebral (28) arteries and veins (4). Multiple compressing vessels were found in 27 cases. Premeatal meningioma and jugular schwannoma were accompanied by vascular compression in 2 cases. Immediate regression of symptoms was observed in 104 patients, partial regression - in 6 patients. Transient facial paresis (4) and impaired hearing (5) were noted after implant interposition. Redo vascular decompression was performed in one case. The most common compressing vessels were cerebellar arteries, vertebral artery and veins. Transposition of arteries is highly effective technique with low incidence of VII-VII nerve dysfunction but relatively slow regression of symptoms.

Three underdogs among galenic veins: anatomical analysis and literature review of surgical relevant veins in the quadrigeminal cistern.

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.

Ultrasound diagnosis of pelvic veins in women of reproductive age

Introduction. Nowadays radiological diagnostics dives particular attention to the research of the pelvic veins in women. Absence of diagnostic criteria for identifying norms do not make it possible to establish the initial disease manifestations. It is also not sufficient enough to make a proper forecast about the formation of pelvic varicose veins.Objective: To study the ultrasound criteria of diagnostic parameters of pelvic veins in women of reproductive age without stated venous pathology.Materials and methods. This research examined 80 young, relatively healthy nulliparous women. The ultrasound criteria of diagnostic parameters of the following veins such as the left renal vein, ovarian veins, cluster-shaped and uterine veins, the angle between the aorta and the superior mesenteric artery, elasticity indices of the common femoral and popliteal veins were studied. Profound data analysis revealed that all patients had significant differences in the left renal vein indices. Based on this data 2 groups were formed: Group 1 (mean age 25.00 ± 3.31 years) 60 people, quite homogeneous according to the studied indices; Group 2 (mean age 24.25 ± 2.61 years) 20 people, quite heterogeneous according to the studied indices. Ultrasonography (Ultrasound examination) was performed using Logiq E9 (GE, USA) and AIXPLORER Super-Sonik Imagine, with convex, endovaginal, and linear sensors. Statistics processing was accom-plished using the StatSoft Statistica 10 software package.Results. In the general sample of patients, positive correlations were found for the following pelvic veins: ovarian veins on both sides, and cerebellar veins on the right side; and cerebellar and uterine veins on the right side. The results of the studied ultrasound parameters in Groups 1 and 2 showed that they differ significantly (p < 0.05). Almost all diagnostic parameters in Group 2 were significantly higher (p < 0.05), all women had anatomical aorto-mesenteric pincer.Conclusion. Ultrasonography of pelvic veins provides information on the anatomical-functional and hemodynamic state of the veins. That is important for prognostication of pelvic varicose veins and revealing asymptomatic forms of this disease.

CS-5 A case of anaplastic pleomorphic xanthoastrocytoma in the pineal region

Tumors in the pineal gland are rare tumors that account for about 0.3% of all brain tumors and have various histological types of tumors develop with germinoma, pineocytoma, and pineoblastoma in that order. On the other hand, pleomorphic xanthoastrocytoma (PXA) is a rare tumor of less than 0.2% and frequently occurs in supratentorial cerebral surface of children and young adults.A case was a 61-year-old man whose pineal tumor was found due to visual disturbance. MRI showed a 23 mm-sized lesion with cysts and inhomogeneous enhancement in the pineal gland. Partial calcification was observed, but there was no non-communicating hydrocephalus, and no increase in HCG-β and AFP with blood sampling. A midline suboccipital craniotomy was performed in the sitting position, a head-up surgery was performed using a 4K / 3D video microscope system (ORBEYE exoscope, Olympus) by the infratentorial supracerebellar approach (ITSCA). The bridging veins and precentral cerebellar vein were dissected to expose the posterior surface of the tumor, and internal decompression was performed. For the complication of air embolism, artificial cerebrospinal fluid was sprayed, and the bilateral internal jugular veins were compressed to confirm the inflow point. There was strong adhesion to the Rt vein of Rosenthal, and the site was removed intracapsularly. Finally, subtotal resection was performed with remaining the upper part of the tumor, a blind lesion behind the Vein of Galen. Vertical gaze palsy occurred after this operation, but it gradually improved over time. Tumor showed pathologically remarkable polymorphism, poor microvascular proliferation and necrosis, but mitotic figures 4–5 / 10HPF, MIB-1 index 10%, GFAP positive, no BRAF V600E mutation. There are few reports of PXA occurring in the pineal gland, and this case is the sixth case. It is also the first report for pineal tumors using ORBEYE through ITSCA in the sitting position.

Falcotentorial Meningioma Resection Through the Supracerebellar Infratentorial Approach: 2-Dimensional Operative Video.

Meningiomas are a common pineal region tumor in adults.1 They frequently reach large size with pending serious neurological consequences.1 Although they are more common in women, their presence in men might raise concerns about a higher-grade meningioma. Accordingly, their treatment starts with surgical resection. Their origin is the falcotentorial junction involving the midbrain tectum and the vital deep venous system. The torcular, transverse sinuses, cerebellar veins, straight sinus, internal occipital veins, basal veins, and internal cerebral veins are encountered requiring a cautious fine intra-arachnoidal dissection under high magnification.2 Multiple surgical approaches are described for pineal area tumors with the advantages and disadvantages of each guiding the selection of the approach.3 We believe that the main deciding factor is the relationship of the vein of Galen and its tributaries to the tumor, simply choosing the route that encounters the tumor first and the vein last. We demonstrate the surgical nuances of removing a pineal area meningioma that displaced the vein of Galen superiorly, prompting the resection through a lateral infratentorial supracerebellar approach. We currently prefer the 3/4 concord position because it provides a superb direct exposure over one cerebellar hemisphere, with the cerebellum relaxed downward while the bridging veins are not severely stretched with gravity.4 The sitting surgeon with resting arms in an ergonomic position is able to perform fine microsurgical dissection over extended time.5 The patient was a 57-year-old man with a large falcotentorial meningioma. The patient consented to the surgery and publication of his images.

Cerebellar venous thrombosis mimicking a cerebellar tumor due to polycythemia vera: a case report

BackgroundCerebral venous thrombosis (CVT) occurs rarely in the general population and is frequently associated with confused clinical findings and delayed diagnosis. Isolated cerebellar cortical vein thrombosis is a very rare phenomenon.Case presentationThis report describes a case with CVT, which is manifested as space-occupying lesions of the cerebellar hemisphere and mimics a cerebellar tumor at the beginning. The diagnosis of CVT was finalized given the laboratory and brain biopsy findings. The etiology may be related to polycythemia vera with Janus Kinase 2 V617F mutation.ConclusionIsolated cerebellar vein thrombosis should be considered when swelling and enhancing cerebellar lesions are detected. Polycythemia vera, especially with a positive JAK2 V617F mutation, may be a rare risk factor for CVT.

Pineal Region Hemangioblastoma Resection Through Paramedian Supracerebellar Approach: 2-Dimensional Operative Video.

Pineal region tumors remain challenging lesions to safely resect because of their central location.1 Patients frequently present with symptoms associated with hydrocephalus and brainstem compression.2 Local anatomy, primarily the tentorium angle and venous anatomy, plays a central role in the selection of the approach.3 The paramedian supracerebellar approach pioneered by Yaşargil in 19844 allows to access the pineal region through a less steep angle while avoiding the central thickened arachnoid and midline cerebellar and vermian veins.3 Although the author strongly prefers the advantageous three-quarter concord position, this early case was performed in a sitting position, which requires a bubble test to rule out the presence of a persistent foramen ovale. The preoperative pineal differential diagnosis should be exhaustive, including blood and cerebrospinal fluid (CSF) tumor markers in suitable cases. Hemangioblastomas are seldom found or expected in the pineal area, and the surgeon must be alarmed by their typical "cherry nodule" appearance.2,5 Their recognition prior to resection is paramount in avoiding excessive blood loss from tumor entry. Similar to arteriovenous malformations, hemangioblastoma surgical tenets include en bloc resection and preservation of the main draining veins until the last steps of the resection. Von Hippel-Lindau (VHL) syndrome genetic workup is necessary is similar patients, as more than 25% of hemangioblastomas are associated with VHL tumor suppressor gene mutations in chromosome 3.2 The patient consented to the surgery and use of her photography. Image at 2:41 from Ueyama et al, Bridging veins on the tentorial surface of the cerebellum: a microsurgical anatomic study and operative considerations, Neurosurgery, 1998, 43(5),3 used with permission from the Congress of Neurological Surgeons.

Major complications of dural venous sinus stenting for idiopathic intracranial hypertension: case series and management considerations

BackgroundVenous sinus stenting (VSS) is a safe, effective, and increasingly popular treatment option for selected patients with idiopathic intracranial hypertension (IIH). Serious complications associated with VSS are rarely reported.MethodsSerious complications...

Bridging veins of the cerebellum: a magnetic resonance imaging study.

To date, no study has yet explored the bridging veins (BVs) of the cerebellum using neuroimaging modalities. Therefore, this study aimed to characterize them using magnetic resonance imaging (MRI). A total of 90 patients with intact cerebellar hemispheres and intracranial dural sinuses underwent thin-sliced, contrast-enhanced MRI. The BVs were classified into six routes based on the draining pattern into the dural sinuses. The superior vermian vein emptying into the straight sinus was delineated in 100% of the patients. The inferior vermian vein emptying into the confluence of the sinuses was identified in 66.7% of the patients. The inferior hemispheric and cerebellar cortical veins emptying into the transverse sinus were identified in 54.4% and 26.7% of the patients, respectively. The inferior vermian and cerebellar cortical veins emptying into the straight sinus were identified in 77.8% and 12.2% of the patients, respectively. The cerebellar cortical vein emptying into the tentorial sinus was identified in 83.3% of the patients; it was delineated on 54 sides with an average number per right hemisphere of 1.9 and 63 sides with an average number per left hemisphere of 2. The pontine-trigeminal and anterior hemispheric veins emptying into the superior petrosal sinus were identified in 42.2% of the patients. The BVs of the cerebellum can be classified into six distinct routes. Radiological classification may be useful for understanding the drainage pattern of the cerebellum.

Microsurgical Neurovascular Anatomy of the Brain: The Posterior Circulation (Part II)

Introduction:Vascular complications of posterior fossa surgery are often deadly although widely preventable through in-depth knowledge of the microsurgical neurovascular anatomy of the infratentorial region and careful surgical planning. The target of this study is to provide a synoptic overview of the normal anatomy and anatomic variants of the infratentorial neurovascular system, critical to safely operate tumors and neurovascular pathologies of the posterior fossa.Methods:Two fresh-frozen and five formalin-fixed cadaveric heads were used. Cervical arteries and internal jugular veins were injected with red and blue latex, respectively. The heads were dissected under a surgical microscope, with magnifications ranging between 3x to 40x, focusing on the infratentorial region. The infratentorial arteries, their collaterals and perforating branches, the brainstem and cerebellar veins, the tentorial venous sinuses, and the relative vascular territories were summarized according to a synoptic approach.Results:The vertebral artery, basilar artery (BA), and posterior cerebral artery (PCA) are the main sources of the arterial supply of the brainstem and cerebellum through the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), the superior cerebellar artery (SCA), and the perforating arteries. The perforating arteries of the vertebrobasilar system derive from the PICA, BA, AICA, SCA, and PCA, and provide for a key contribution to the vascularization of the midbrain, pons, medulla oblongata, fourth ventricle, cerebellar and cerebral peduncles, thalamus, hypothalamus, subthalamus, posterior part of the internal capsule, and optic tract. The distal segments and branches of the PCA also add a significant arterial supply to the temporal, occipital, and parietal lobes. The venous outflow of the posterior fossa is a prerogative of the internal jugular veins via the tentorial venous sinuses.Conclusion:A perfect mastery of the arterial, venous, and cisternal anatomy of the infratentorial region is vital for the planning and execution of the whole range of posterior fossa approaches.

Dural Venous Channels: Hidden in Plain Sight-Reassessment of an Under-Recognized Entity.

Tentorial sinus venous channels within the tentorium cerebelli connecting various cerebellar and supratentorial veins, as well as the basal vein, to adjacent venous sinuses are a well-recognized entity. Also well-known are "dural lakes" at the vertex. However, the presence of similar channels in the supratentorial dura, serving as recipients of the Labbe, superficial temporal, and lateral and medial parieto-occipital veins, among others, appears to be underappreciated. Also under-recognized is the possible role of these channels in the angioarchitecture of certain high-grade dural fistulas. A retrospective review of 100 consecutive angiographic studies was performed following identification of index cases to gather data on the angiographic and cross-sectional appearance, location, length, and other features. A review of 100 consecutive dural fistulas was also performed to identify those not directly involving a venous sinus. Supratentorial dural venous channels were found in 26% of angiograms. They have the same appearance as those in the tentorium cerebelli, a flattened, ovalized morphology owing to their course between 2 layers of the dura, in contradistinction to a rounded cross-section of cortical and bridging veins. They are best appreciated on angiography and volumetric postcontrast T1-weighted images. Ten dural fistulas not directly involving a venous sinus were identified, 6 tentorium cerebelli and 4 supratentorial. Supratentorial dural venous channels are an under-recognized entity. They may play a role in the angioarchitecture of dural arteriovenous fistulas that appear to drain directly into a cortical vein. We propose "dural venous channel" as a unifying name for these structures.

Microsurgical Technique for Treatment of Perimedullary Spinal Arteriovenous Fistulae: 2-Dimensional Operative Video

The case is of a 49-yr-old female admitted after acute onset lower cervical/upper thoracic region pain with left hemi-body hypoesthesia below the C7 level. Magnetic resonance imaging showed a spinal cord intraparenchymal hemorrhage at the C6/7 levels. Physical exam revealed hypoesthesia on the left from C7 and below with associated 3/5 wrist and finger extensor and 4/5 triceps strength on the left. The remainder of the neurological exam was normal including lower extremity strength and bowel/bladder function. A craniocervical angiogram showed a perimedullary arteriovenous fistula on the left, ventrolateral aspect of the spinal cord with a single feeding artery that originated from the thyrocervical trunk and entered through the left C6 nerve root sleeve. Venous drainage was cephalad to cortical cerebellar veins and to the suboccipital plexus. A branch of the thyrocervical trunk supplying the ventral spinal cord originated close to the fistula, which precluded endovascular embolization. The patient underwent C6-T1 laminectomies for microsurgical treatment of the fistula. This case demonstrates multiple key concepts in the surgical management of these rare lesions as follows: the ventral aspect of the cervical spinal cord can be safely approached from posterior. The venous anatomy is often confusing and intraoperative angiography utilizing both indocyanine green and conventional digital subtraction techniques are of paramount importance. Unlike arteriovenous malformations, the venous drainage can be pruned to gain visualization and trace the venous anatomy retrograde to the point of the fistula. The patient awoke from surgery at her neurological baseline. The patient consented to de-identified publication of this case.

Supracerebellar Infratentorial Endoscopy for Quadrigeminal Cistern Epidermoid

The standard microscopic supracerebellar infratentorial approach for the pineal region is limited by tunnel vision. Herein, we describe endoscopic supracerebellar infratentorial surgery in a patient with quadrigeminal cistern epidermoid presenting with hydrocephalus. In the sitting position, following a 6 cm longitudinal incision and small suboccipital craniotomy, the dura was cut in V shape and kept reflected. The bridging veins were coagulated and cut, taking the 0° endoscope inside. A sharp incision is given over the thickened arachnoid over the inferior paramedian area. The precentral cerebellar vein is exposed at the lower part, coagulated and divided. Gentle bimanual intracapsular removal of the epidermoid flakes is performed with intermittent saline irrigation and suction. Assisted by rotating the angled endoscope, curved coaxial instruments help remove the cerebello-mesencephalic and lateral extensions of the epidermoid. Endoscopic supracerebellar infratentorial approach provides a panoramic and angled view of the pineal region, through a narrow corridor, avoiding cerebellar retraction.

Safe handling of veins in the pineal region-a mixed method study.

Surgical experience in pineal surgery is largely confined to a few experienced surgeons and may be lost when they stop their practice. The objective of this study is to systematically preserve and analyze valuable practical knowledge of pineal region surgical venous anatomy. A survey was constructed to obtain experienced surgeons' perception of estimated risks and individual experience following occlusion of veins during pineal surgery. Data were qualitative and analyzed with a mixed methods approach. Of the 126 invited neurosurgeons, 40 submitted completed questionnaires. General agreement existed of which veins were associated with high and low risks following occlusion. The risk of death was estimated to be high with sacrifice of the vein of Galen (83%), both internal cerebral veins (69%) and the basal veins (58%). The risk of death was estimated to be lower with the sacrifice of both superior vermian veins (13%) and one internal occipital vein (10%). Importantly, a sub-group of experienced surgeons reported substantial risk of death and consequences with the sacrifice of cerebellar bridging veins (8-13%). Our findings provide a coherent picture of surgical risk with venous sacrifice, which can inform the surgical community of systematically gathered views from aggregated surgeries of a very large cohort of patients. Extensive presurgical radiological workup and anatomical studies seemed to correlate more cautious risk estimations. Our findings increase available knowledge of risks of venous complications.