Precentral Cerebellar Vein Research Articles

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.

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.

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.

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.

What is the risk of venous infarction to intra-operative sacrifice of either the superficial or deep cerebral bridging veins?

Dear Editor: In the article entitled “The intracranial bridging veins: a comprehensive review of their history, anatomy, histology, pathology, and neurosurgical implications” by Mortazavi et al [1], the authors state in the section entitled Surgical significance of the bridging veins, “Furthermore, identification of the bridging veins during surgery makes the neurosurgeon aware of avoiding damage to them in order to prevent venous infarction secondary to iatrogenic occlusion of these veins.” Although this is a concept that is widely accepted, one could question what evidence exists to support this conclusion. The most direct route to many midline cerebral lesions is often barred by the presence of superficial or deep bridging veins. Because of the perceived consequence of surgically occluding and dividing these veins, imaging studies are frequently obtained to map a corridor that may be less direct and/or restricted so as to avoid these veins in order to reach the desired destination. This can result in a less than optimal exposure and ability to achieve the ideal outcome be it greater or complete tumor resection or reduced collateral involvement of structures adjacent to the target location. Conventional wisdom predicts venous infarction is likely to occur with obstruction to either the superficial or deep bridging veins [2]. Extensive connections exist between the superficial and deep venous systems with a significant degree of overlap and bidirectional flow as the cerebral veins have no valves [3]. The extensive anastomotic nature of the cerebral venous system allows venous drainage to be altered as needed through the numerous collateral pathways. We have reported on our own experience in a pediatric population of occluding one or more middle-third superior sagittal sinus cortical bridging veins in 63 patients as the initial intracranial step in a transcallosal approach to deep midline tumors without a single incidence of venous infarction [4]. This study was followed by a second publication investigating a retrocallosal approach to pineal lesions wherein superficial bridging veins were sacrificed in seven patients and deep bridging veins (basal vein of Rosenthal, internal cerebral vein, and precentral cerebellar vein) in another three patients with no evidence of venous infarction [5]. In a third publication, we reviewed the clinical and experimental literature regarding the effects of sacrificing the deep cerebral veins and did not find evidence of the dire consequences of venous infarction that conventional wisdom espouses [6]. It is highly suspected that the sequelae attributed to occluding the superficial and deep bridging cerebral veins result from brain retraction, especially against gravity (Fig. 1) [7] and can be avoided by positioning the patient and using an approach wherein gravity is an ally and not an enemy. Using the most direct approach to the region of interest without regard to the location of the bridging cerebral veins is of significant advantage. J. G. McComb Division of Neurosurgery, Children’s Hospital of Los Angeles, 1300 N. Vermont Ave, Doctor’s Tower, Suite 1006, Los Angeles, CA 90027, USA

DEPICTION OF SMALL VEINS DRAINING INTO THE VEIN OF GALEN USING PREOPERATIVE 3-DIMENSIONAL NAVIGATION IN LIVING PATIENTS

The purpose of this study was to delineate the anatomy of the precentral cerebellar vein, superior vermian vein, and internal occipital vein using reconstructions of computed tomographic and magnetic resonance imaging scans with navigation software. These data were compared with previous anatomic and angiographic findings to show the resolution and accuracy of the system. We retrospectively reviewed 100 patients with intracranial pathologies (50 computed tomographic scans with contrast and 50 magnetic resonance imaging scans with gadolinium) using a neuronavigation workstation for 3-dimensional reconstruction. Particular attention was paid to depiction of the precentral cerebellar vein, superior vermian vein, and internal occipital vein. The data were reviewed and analyzed. The precentral cerebellar vein, superior vermian vein, and its tributary, the supraculminate vein, were depicted in 52 (52%) patients. The internal occipital vein was delineated on 99 (49.5%) sides and joined the basal vein and vein of Galen in 39 (39.4%) and 60 (60.6%) hemispheres, respectively. Comparing these results with previous angiographic studies, the ability of the neuronavigation system for depicting these vessels is similar to that of digital subtraction angiography. This study illustrates the possibility of depicting the small vessels draining into the pineal region venous complex using 3-dimensional neuronavigation with an accuracy comparable to that of digital subtraction angiography. This tool provides important information for both surgical planning and intraoperative orientation.

Three-dimensional Computed Tomography Angiography of the Galenic System for the Occipital Transtentorial Approach

The venous variations of the galenic system were evaluated using three-dimensional computed tomography angiography (3D-CTA) to assess the influence on the occipital transtentorial approach in 150 patients who underwent 3D-CTA as a routine screening examination for cerebrovascular diseases. The variations of the vein of Galen with its tributaries, the tentorial sinus, and the veins around the tentorium were evaluated in multiple intensity projections and stereoscopic images. The angle between the vein of Galen and the straight sinus was 67.1 +/- 31.9 degrees (mean +/- SD). Observation of the pineal body from the direction of the approach tended to extend to the quadrigeminal bodies in acute angle cases, and to the third ventricle in obtuse angle cases. Bilateral internal cerebral veins (ICVs) joined in the anterior portion were associated with a long vein of Galen, or in the posterior portion with a short vein of Galen. The distance between the bilateral ICVs was 4.66 +/- 2.28 mm (mean +/- SD), and the shape of the space could be classified as spindle, parallel, hairpin, and round types. The basal vein could be classified into well-developed, hypoplastic, hardly recognized, and mimicking two basal veins because the tributary did not join but ran parallel to the basal vein. The drainage pathways lead to the anterior or posterior portion of the vein of Galen, the ICV, the tentorial sinus, and the superior petrosal sinus. The various types of the tentorial sinus and primitive tentorial sinus which might be sacrificed during section of the tentorium were confirmed. The inferior cerebral vein draining to the tentorial sinus could be seen. 3D-CTA could also demonstrate the presence, the course, and the drainage points of the internal occipital vein, the precentral cerebellar vein, the posterior pericallosal vein, and so on. 3D-CTA is useful to evaluate the variations of the venous system and the relationship with the tumor, and for preoperative simulation and intraoperative navigation of the occipital transtentorial approach.

Venous Angioma of the Posterior Fossa

The authors report 2 cases of venous angioma of the posterior fossa, an uncommon disorder. Case 1: A 17-year-old boy was admitted complaining of dizziness, headache, and vomiting. Neurological examination disclosed conjugate deviation to the right, left-sided limb and truncal ataxia, gait disturbance, and dysarthria. Plain computerized tomography (CT) showed a highdensity area indicating a hematoma in the left cerebellum. Enhanced CT showed a linear enhancement inside the hematoma, probably corresponding to a dilated draining vein. Vertebral angiography revealed a venous angioma in the early venous phase that was drained into a dilated precentral cerebellar vein. Case 2: A 33-year-old female was admitted complaining of nausea, vomiting, and vertigo. Neurological examination disclosed dysarthria, right-sided limb and truncal ataxia, and Bruns nystagmus. Plain CT showed a high-density area indicating a hematoma in the right cerebellum. Enhanced CT showed a nodular enhancement inside the hematoma, probably corresponding to a dilated draining vein. Vertebral angiography revealed a venous angioma in the early venous phase that was drained into a dilated inferior hemispheric vein. Surgical removal of the angioma was successfully performed in both cases. Radical operation is recommended in cases of hematoma because the frequency of rebleeding is high.

Microsurgical anatomy of the pineal region.

The microsurgical anatomy of the pineal region was studied in 30 cadaver brains after the injection of a colored barium/gelatin mixture into the basilar artery and the straight sinus. The relationships of the pineal gland, vein of Galen, precentral cerebellar vein, internal cerebral veins, basal veins of Rosenthal, medial posterior choroidal arteries, quadrigeminal plate, pulvinar, splenium of the corpus callosum, and posterior 3rd ventricle were examined with the operating microscope and are described.

Microsurgical anatomy of the pineal region

The microsurgical anatomy of the pineal region was studied in 30 cadaver brains after the injection of a colored barium/gelatin mixture into the basilar artery and the straight sinus. The relationships of the pineal gland, vein of Galen, precentral cerebellar vein, internal cerebral veins, basal veins of Rosenthal, medial posterior choroidal arteries, quadrigeminal plate, pulvinar, splenium of the corpus callosum, and posterior 3rd ventricle were examined with the operating microscope and are described. (Neurosurgery, 6: 385-390, 1980)

Die Venen des menschlichen Kleinhirns

(1) The veins of the human cerebellum, which may be classified into internal and external venous channels, correspond, in this respect, to the veins of the cerebral hemispheres. (2) The external cerebellar veins are arranged in three groups which, in turn, correspond to the three cerebellar surfaces and which communicate extensively. Accordingly, the terminal segments of the cerebellar veins overlap, which implies that no one-to-one relationship exists between the mouths of the individual veins and their respective distributions. (3) The terminal segments of the cerebellar veins are the superior petrosal sinus, the tentorial venous sinuses, the great vein of Galen and the internal vertebral plexus. (4) The tentorial venous channels may form a collateral venous arrangement. (5) The internal cerebellar veins consist of the nuclear veins and the medullary veins. (6) The medullary veins form a cortex-perforating group and a group located in the basal medullary region. The latter form a venous arborization of blood vessels not described thus far. This group of veins opens chiefly into the vein of the lateral recess of the fourth ventricle.(7) Attention is called to a 'venous watershed' corresponding to the one that exists in the cerebral hemispheres. (8) The veins of the dentate nucleus are composed of several venous channels draining its external surface and one single vein draining its internal surface. The latter has not been described thus far. The external veins of the dentate nucleus open into the venous star and the cortex-perforating veins. The internal nuclear vein, on the other hand, emerging from the hilum of the dentate nucleus, runs along the superior cerebellar peduncle. Thus, the term 'vena centralis nuclei dentati' appears to be appropriate to designate this vessel. It ultimately opens into the precentral cerebellar vein. (9) In certain places, various-colored substances used for injection form mixed pools.

Venous malformation drained by the precentral cerebellar vein: An angiographic and post-mortem study

The angiographic and post-mortem study of a vascular malformation drained by the precentral cerebellar vein is presented. Both indicate the purely venous nature of this blood-vessel harmartoma and support the recognition of this separate type of vascular malformation in the central nervous system.

Arterial and venous signs of tumors within the fourth ventricle.

A positive diagnosis of tumors located within the fourth ventricle should be based on specific signs therby excluding other space occupying lesions in the posterior fossa. These are a typical omega form of the hemispheric cerebellar branches on the lateral projection, and an also typical inverted 3 form of the PICA in the semiaxial projection. Alteration of the veins of the lateral recess of the fourth ventricle and of the precentral cerebellar vein are important venous signs. Indirect signs are found in the absence of tonsillar herniation with arterial and venous signs of AP stretching of the cerebellar tonsils.

Precentral cerebellar vein in cystic astrocytomas of the vermis.

A peculiar abnormality of the precentral cerebellar vein seen only in cystic astrocytoma of the vermis is reported. Implications of this angiographic finding are discussed. The importance of posterior fossa angiography (especially venography) in the diagnosis of posterior fossa mass lesions is emphasized.

The vertebral angiogram in patients with tumours in or near the midline.

A description is given of the vascular features of the vertebral angiogram observed in patients with midline tumours. Supratentorial tumours are most likely to cause displacement of the posterior choroidal arteries and the thalamic veins. Examples of tumours of the hypothalamus, thalamus, pineal body, splenium of the corpus callosum and tectorial membrane of the midbrain are present. Infratentorial tumours are most likely to displace the posterior inferior cerebellar arteries, the precentral cerebellar vein and the pontomesencephalic vein. Examples are given of tumours of the pons cerebelli and the fourth ventricle, and of cysts in the cisterna magna.

Diagnosis of posterior fossa lesions by angiography.

Abstract Characteristic angiographic changes found in posterior fossa mass lesions are described. The importance and reliability of landmarks such as the anterior ponto-mesencephalic vein, the precentral cerebellar vein, the superior vermal branch of the superior cerebellar artery and the cranial loop of the posterior inferior cerebellar artery are emphasised. Measurements considered helpful are: (a) distance between the clivus and the colliculo-central point of the precentral cerebellar vein: normal variation is between 36 and 43 mm; (b) distance between the interpeduncular loop of the anterior ponto-mesencephalic vein and the colliculocentral point: normal variation is between 19 and 24 mm; (c) position of the cranial loop of the posterior inferior cerebellar artery reported with a perpendicular to the Twining's line: normal variation is between 52 and 60 per cent from the tuberculum sellae.

Diagnostic value of the precentral cerebellar vein in cases of the posterior fossa tumors.

1) The precentral cerebellar vein begins between the lingula and the central lobe and runs upwards behind the anterior medullary velum in midline.2) The normal course and configuration of this vein was described. The minimal distance from this vein to the posterior aspect of the clivus averaged 38 mm with a range of 31 to 43 mm as measured in 40 normal cases.3) The deformities and displacement of this vein indicate the changes in the aqueduct and the upper part of the fourth ventricle caused by tumors of mesencephalon, pons and cerebellum.4) Diagnostic value of this vein is highly evaluated in the vertebral angio-graphy by the authors.

Angiographic features of aqueductal stenosis.

1. The diagnosis of simple aqueductal obstruction in adults can usually be suspected from cerebral angiography, provided both supra- and infra-tentorial vessels are well opacified. The morphologic changes seen in aqueductal stenosis are the result of marked pressure hydrocephalus involving the lateral ventricles, the third ventricle and upper portion of the aqueduct above the obstruction with resultant downward axial herniation and compression of the upper brain stem. Narrowing of the anterior basal cisterns and dilatation of the posterior basal cisterns at the tentorial notch are usually marked.2. The angiographic features faithfully reflect the morphologic changes and are described in detail.3. A characteristic deformity of the superior vermis demonstrated by changes in the course of the precentral cerebellar vein and of branches of the superior cerebellar artery is described and illustrated.4. Although the angiographic features of simple aqueductal obstruction in adults are characteristic, contrast stu...

The veins of the posterior fossa--superior or galenic draining group.

1. The posterior fossa venous system can be divided into three groups: (a) a superior group draining into the galenic system; (b) an anterior group draining into the petrosal sinuses; and (c) a posterior group draining into the torcular and neighboring dural sinuses.2. The first group of the veins of the posterior fossa is the subject of this paper.[See figure in the PDF file]This group includes the posterior mesencephalic vein, the lateral mesencephalic vein, the precentral cerebellar vein and its variants, and the superior vermian vein. The anterior ponto-mesencephalic vein which may belong to this group is briefly described.3. Particular attention is given to the relationship of these vessels with the structures of the posterior fossa, i.e., brain stem and cerebellum.4. The appearance of these vessels normally and in several patients with expanding lesions is illustrated.