Microsurgical anatomy of the veins of the posterior fossa

The microsurgical anatomy of the veins of the posterior fossa was defined in 25 cadavers. These veins are divided into four groups: superficial, deep, brain-stem, and bridging veins. The superficial veins are divided on the basis of which of the three cortical surfaces they drain: the tentorial surface, which faces the tentorium and is exposed in a supracerebellar approach, is drained by the superior hemispheric and vermian veins; the suboccipital surface, which is below and between the lateral and sigmoid sinuses and is exposed in a wide suboccipital craniectomy, is drained by the inferior hemispheric and inferior vermian veins; and the petrosal surface, which faces forward toward the posterior surface of the petrous bone and is retracted to expose the cerebellopontine angle, is drained by the anterior hemispheric veins. The deep veins course in the three fissures between the cerebellum and the brain stem, and on the three cerebellar peduncles. The major deep veins in the fissures between the cerebellum and brain stem are the veins of the cerebellomesencephalic, cerebellomedullary, and cerebellopontine fissures, and those on the cerebellar peduncles are the veins of the superior, middle, and inferior cerebellar peduncles. The veins of the brain stem are named on the basis of whether they drain the midbrain, pons, or medulla. The veins of the posterior fossa terminate as bridging veins, which collect into three groups: a galenic group which drains into the vein of Galen; a petrosal group which drains into the petrosal sinuses; and a tentorial group which drains into the tentorial sinuses near the torcula.     

Anatomic variations of venous sinuses in the region of the torcular Herophili

In this study of 110 cranial cavities from adult cadavers, the superior sagittal sinus was found to divide into two channels. In most cases, the division was associated with a dural partition. Essentially, the variations as observed in this study could be grouped into three types: Type 1 includes those specimens in which the sagittal sinus drains into one lateral sinus and the straight sinus into the other, with no connection between the two. Type 2 includes those specimens in which the superior sagittal sinuses and the straight sinus fork, and the forks from both sinuses join to form the lateral sinuses. Type 3 includes those specimens in which a confluence of sinuses exists, varying from a common pool to merely a potential confluence, depending upon the presence of pads, incomplete partitions, and complete partitions of dura mater. Rare findings previously not reported consist of double straight sinuses draining into one transverse sinus; the superior sagittal sinus dividing into three channels with two transverse sinuses on one side; a transverse sinus originating from a tentorial vein; and drainage of a tentorial vein into the confluence of sinuses.     

Persistent falcine sinus associated with obstruction of the superior sagittal sinus caused by meningioma--case report

A 72-year-old woman presented with meningothelial meningioma causing obstruction of the superior sagittal sinus (SSS). Magnetic resonance imaging demonstrated the lesion in the left occipital parasagittal region and a linear vascular structure in the posterior falx extending from the vein of Galen to the SSS. Cerebral angiography demonstrated obstruction of the posterior portion of the SSS and venous flow from the bilateral occipital lobes draining into the falcine sinus and then into the vein of Galen. The tumor was subtotally removed with preservation of the falcine sinus and bridging veins draining into the sinus. The falcine sinus is usually obliterated after birth, but may persist into adulthood and be involved in unusual draining patterns.     

Anatomical landmarks for hemispherotomy and their clinical application

OBJECT: The authors introduce the surgical concept of the central core of a hemisphere, from which anatomical structures are disconnected during most current hemispherotomy techniques. They also propose key anatomical landmarks for hemispherotomies that can be used to disconnect the hemisphere from its lateral surface around the insula, through the lateral ventricle toward the midline. METHODS: This anatomical study was performed in five adult cadaveric heads following perfusion of the cerebral arteries and veins with colored latex. Anatomical landmarks were used in five hemispheric deafferentations. The central core of a hemisphere consists of extreme, external, and internal capsules; claustrum; lentiform and caudate nuclei; and thalamus. Externally, this core is covered by the insula and surrounded by the fornix, choroid plexus, and lateral ventricle. During most hemispherotomies, the surgeon reaches the lateral ventricle through the frontoparietal opercula or temporal lobe; removes the mesial temporal structures; and disconnects the frontal lobe ahead, the parietal and occipital lobes behind, and the intraventricular fibers of the corpus callosum above the central core. After a temporal lobectomy, the landmarks include the choroid plexus and posterior/ascending portion of the tentorium to disconnect the parietal and occipital lobes, the callosal sulcus or distal anterior cerebral artery (ACA) to sever the intraventricular fibers of the corpus callosum, and the head of the caudate nucleus and ACA to detach the frontal lobe. CONCLUSIONS. These landmarks can be used in any hemispherotomy during which a cerebral hemisphere is disconnected from its lateral surface. Furthermore, they can be used to perform any resection around the central core of the hemisphere and the tentorial incisura.     

Microsurgical anatomy of the tentorial sinuses

Variations of the tentorial sinus of cadaver cerebellar tentoria were examined under a surgical microscope. The tentorial sinuses were classified into four groups: Group I, in which the sinus received venous blood from the cerebral hemisphere; Group II, in which the sinus drains the cerebellum; Groups III, in which the sinus originates in the tentorium itself; and Group IV, in which the sinus originates from a vein bridging to the tentorial free edge. The tentorial sinuses of Groups I and II were frequently located in the posterior portion of the tentorium. The sinuses of Group I were short and most frequently present in the lateral portion of the tentorium. The tentorial sinuses of Group II, which were usually large and drained into the dural sinuses near the torcular, were separated into five subtypes according to the draining veins and direction of termination. The tentorial sinuses of Groups III and IV were located near the tentorial free edge or the straight sinus. The draining patterns of the tentorial sinuses and their draining veins (so-called "bridging veins") were present in most cases. Knowledge of this anatomy can benefit the neurosurgeon carrying out repair near or on the cerebellar tentorium.     

Microsurgical anatomy of the venous drainage into the superior sagittal sinus

Ten unfixed human brains were examined under an operating microscope to evaluate the feasibility of reimplanting the parasagittal veins into the superior sagittal sinus. On average, there were 6.5 veins draining the surface of each hemisphere in the anterior frontal region, 3 veins draining each posterior frontal region, 4 veins draining each parietal region, and 1 vein draining each occipital region. The veins were most frequently 0.1 to 1.0 mm in diameter, but were as large as 3.0 mm in the anterior frontal and occipital regions, 3.5 mm in the parietal region, and 5.0 mm in the posterior frontal region. The mean vein length between the superior sagittal sinus and the first lateral attachment was 3.0 to 7.4 mm; individual veins were as long as 30.0 mm. The 20 hemispheres contained a total of 5 veins in the anterior frontal region, 7 veins in the posterior frontal region, and 8 veins in the parietal region that appeared to have an adequate diameter and length for microsurgical reimplantation into the superior sagittal sinus. The superior sagittal sinus had a mean width of 4.3 mm and depth of 3.6 mm in the midanterior frontal region and enlarged to a mean width of 9.9 mm and depth of 6.8 mm in the midoccipital region. In all sites, the sinus appeared to be structurally compatible with vein reimplantation. In 3 cases, veins 2.8 to 4.6 mm in diameter were reimplanted microsurgically into the sinus; in each case, the anastomosis was technically satisfactory and patient.(ABSTRACT TRUNCATED AT 250 WORDS)     

A case of successfully removed posttraumatic high flow dural arteriovenous fistula in the posterior fossa

A 49-year-old male patient was admitted to Ryukyu University Hospital complaining chiefly of progressive loss of mental activity for one year. He had a history of head trauma at the right retromastoid region when he was 24. Generalized convulsions developed three years later, and left exophthalmos, facial varix and impairment of visual acuity developed seven years later. Dural arteriovenous fistula of the posterior fossa was diagnosed at the age of 32, and feeding EC and tentorial arteries were successively ligated on the right several times without any effect. Angiography during this admission revealed tremendous collateral flows; a marked dilated tortuous occipital artery fed from the right vertebral artery, meningeal branches of VA and PICA, the marginal tentorial artery, and the posterior temporal artery from MCA, PCA were drained into the right transverse sinus. But transverse sinuses were occluded bilaterally, and venous outflows were directed to the superior sagittal sinus retrograde via the ascending cortical vein, Trolard veins, and sphenoparietal and cavernous sinuses. The final drainer was the superior ophthalmic vein on the left. Normal deep veins were not visible. In park bench position, the nidus was totally resected with a part of the transverse and thrombosed sigmoid sinus. Postoperative course was uneventful, and an angiogram showed complete disappearance of the AVF. Dural AVG in the posterior fossa with characteristics such as high flow, and which is rich in collaterals following palliative treatment indicates that total surgical resection should be undertaken.     

Anatomy of the falcine venous plexus

OBJECT: The superior and inferior sagittal sinuses have been well studied. Interestingly, other venous structures within the falx cerebri have received scant attention in the medical literature. The present study was performed to elucidate the presence and anatomy of these midline structures. METHODS: The authors examined 27 adult latex- or ink-injected cadaveric specimens to observe the morphological features of the sinuses within the falx cerebri (excluding the inferior and superior sagittal sinuses). RESULTS: All specimens were found to have an extensive network of small tributaries within the falx cerebri that were primarily concentrated in its posterior one third. In this posterior segment, these structures were usually more pronounced in the inferior two thirds. The portion of the falx cerebri not containing significant falcine venous sinus was termed a "safe area." These vascular channels ranged in size from 0.5 mm to 1.1 cm (mean 0.6 mm); 100% of these vessels communicated with the inferior sagittal sinus. Classification of the structures was then performed based on communication of the falcine venous sinus with the superior sagittal sinus. Type I falcine sinuses had no communication with the superior sagittal sinus, Type II falcine sinuses had limited communication with the superior sagittal sinus, and Type III falcine sinuses had significant communication with the superior sagittal sinus. Seventeen (63%) of 27 specimens communicated with the superior sagittal sinus (Types II and III). Further subdivision revealed 10 Type I, seven Type II, and 10 Type III falcine venous plexuses. CONCLUSIONS: There are other venous sinuses in the falx cerebri in addition to the superior and inferior sagittal sinuses. Neurosurgical procedures that necessitate incising or puncturing the falx cerebri can be done more safely via a described safe area. Given that the majority of specimens in the authors' study were found to have a plexiform venous morphology within the falx cerebri, they propose that these channels be referred to as the falcine venous plexus and not sinus. The falcine venous plexus should be taken into consideration by the neurosurgeon.     

Papillary meningioma arising from the confluens sinuum with multidirectional extension through venous sinuses

Successful removal of a meningioma arising from the confluens sinuum is described. This tumor extended multidirectionally through the venous sinuses (superior sagittal sinus, bilateral transverse sinuses, straight sinus, and occipital sinus) and protruded like a club in nodular pattern from the left inner surface of the confluens sinuum into the left occipital lobe. The tumor was completely removed via a bilateral large parieto-occipito-suboccipital craniotomy. Angiographically, unusual venous drainage from the vein of Galen into the superior sagittal sinus was demonstrated. Histologically, this tumor was a papillary meningioma characterized by two types of papillary structure in many areas.     

A case of dural arteriovenous malformation in the anterior fossa

Dural arteriovenous malformations (AVMs) are not uncommon. But most of dural AVMs are located in the cavernous portion or the transverse-sigmoid portion. Dural AVMs in the anterior fossa and very rare. We experienced a case of dural AVM in the anterior fossa and review 17 cases of dural AVM in the anterior fossa in the literature. Case: a 62-year-old male was admitted to our center because of unconsciousness and vomiting on Sept. 28; 1985. For nineteen months he had been on anticoagulant therapy after aorto-coronary bypass. Neurological examination on admission revealed somnolence and right-hemiparesis. CT scan revealed intracerebral hematoma in the left frontal lobe with ventricular perforation. Enhanced CT scan revealed patchy enhancement in the tip of the left frontal lobe. Selective angiographies were performed. Dural AVM, fed by both anterior ethmoidal arteries and drained by the cortical veins into the superior sagittal sinus and left superficial middle cerebral vein, was found. Selective external carotid angiography failed to visualize any AVM. MRI revealed spotty low signal intensity in the frontal tip by inversion recovery and spin echo. After admission his consciousness and right-hemiparesis improved completely. Left frontal craniotomy was done. On opening the dura, aneurysmal dilatation was found in the left frontal lobe, arising from the inner surface of the dura at the antero-medial corner of the left anterior fossa. From this aneurysmal dilatation a few veins entered the superior sagittal sinus. Red veins including aneurysmal dilation was removed from its origin together with the intracerebral hematoma. (ABSTRACT TRUNCATED AT 250 WORDS)     

Dural arteriovenous fistulas of the posterior cerebral fossa and thrombosis of the lateral sinus. Discussion of their relations and treatment apropos of 2 cases

Two cases of a posterior fossa dural arteriovenous malformation associated with a lateral sinus thrombosis are reported. In the first case, a right tentorial meningioma develops at the end of the superior sagittal sinus and on the transverse sinus which are occluded. A cranial bruit, heard by the patient four months after the surgical removal of the tumour, brings up a dural fistula supplied by the occipital, middle meningeal and pharyngeal arteries and drained away by cervical and cortical veins. Many attempts of extirpation and radiological embolization stop the bruit. In the second case, an increased intracranial pressure mixes up with an aphasia. A continuous emission doppler examination and a CT scan make likely a dural fistula. The malformation, which is associated to a left sigmoid sinus thrombosis, is fed by the occipital and middle meningeal arteries and drained by cortical veins to the cavernous sinus. The occipital artery ligation and a by-pass between the lateral sinus and the internal jugular vein cure the patient with a very good patency of the venous graft that holds up two years after. A few cases of the literature show the succession of the two vascular lesions and prove the primitive occurrence, either of the sinus occlusion, or of the dural fistula. A venous thrombosis might cause a fistula by the opening of physiological shunts of the dura-mater which consequently deviates the blood into the cortical veins, brings down the increased intracranial pressure and stops the thrombosis to spread.(ABSTRACT TRUNCATED AT 250 WORDS)     

The lateral position — Dependant occipital approach — to pineal and medial occipitoparietal lesions

Summary A recent modification of the occipital transtentorial approach to the pineal region and medial-posterior hemisphere is described. The patient is operated upon in a lateral reclining (park bench) position with the side to undergo occipitoparietal craniotomy, slightly dependant. Following dural opening to the margins of the superior sagittal and lateral sinuses, gentle traction with a brain spatula facilitates the occipital transtentorial and transfalcine approach to the incisural region. Ventricular or spinal fluid drainage is often helpful. The occipital lobe falls away from the midline and falcotentorial regions by gravity. Absence of occipital parasagittal bridging veins is a helpful feature and careful convexity dural opening allows the occipital lobe to move laterally. Microsurgical treatment of pineal, splenial, falcotentorial and medial posterior hemisphere lesions may be greatly facilitated. Our experience with six cases is presented. To date, published results of this operative approach have been excellent with the risk of hemianopsia, parenchymal venous infarction, and air embolus much lessened or eliminated.     

The pretemporal approach to the interpeduncular and petroclival regions

Summary A pretemporal approach to the interpeduncular and petroclival regions is described.Through a frontotemporal craniotomy based very low in the middle fossa the temporal lobe is completely exposed. The Sylvian, carotid, chiasmatic, and lamina terminalis cisterns are widely opened. The arachnoid fibers between the uncus and the frontal lobe, as well as those binding the temporal lobe to the tentorial edge and to the oculomotor nerve are also separated. The bridging veins from the temporal pole to the spheno-parietal sinus are usually coagulated and sacrificed allowing for posterior displacement of the temporal lobe.The approach combines the advantages of both the classical pterional and subtemporal approaches providing unhindered exposure of the anterior portion of the tentorial incisura in dealing with vascular and tumoural lesions arising at the sellar, parasellar, and interpeduncular regions, and at the superior aspect of the petroclival region.     

The variations of sylvian veins and cisterns in anterior circulation aneurysms

Summary The anatomical variations of Sylvian vein and cistern were investigated during the pterional approach in 230 patients with 276 aneurysms of anterior circulation arteries, that were operated on at the Neurosurgical Department of Atatürk University Medical School, Erzurum, Turkiye. All patients underwent radical surgery for aneurysm by the right or left pterional approach. The findings were recorded during surgical intervention and observed through the slides and videotapes of the operations.In our study, we surgically classified the variations of the Sylvian vein, according to its branching and draining patterns. Type I: The fronto-orbital (frontosylvian), fronto-parietal (parietosylvian) and anterior temporal (temporosylvian) veins drain into one sylvian vein. Type II: Two superficial Sylvian veins with separated basal vein draining into the sphenoparietal and Rosenthal's basal vein. Type III: Two superficial Sylvian veins draining into the sphenoparietal and the superior petrosal veins. Type IV: Hypoplastic superficial Sylvian vein and the deep one. Four types of Sylvian vein variations were defined as follows. The Type I was seen in 45% (n = 103), the Type II was found in 29% (n = 67), Type III was recorded in 15% (n = 34) and Type IV, or hypoplastic and deep form was discovered in 11% (n = 26) of patients. The course of the Sylvian vein was on the temporal side (Temporal Coursing) in 70 percent of the cases (n= 160), on the frontal side (Frontal Coursing) in 19% of the patients (n = 45) and in 8 percent of the cases (n= 18) in the deep localization (Deep Coursing). Only 3 percent of the cases (n = 7) showed a mixed course. The variations of the Sylvian cisterns were classified into three types, according to the relationships between the lateral fronto-orbital gyrus and the superior temporal gyrus. In Sylvian Type, the frontal and temporal lobes are loosely (Sylvian Type A, Large) or tightly (Sylvian Type B, Close and Narrow) approximated on the surface thereby covering the area of the Sylvian cistern. In frontal type, the proximal part of the lateral fronto-orbital gyrus herniated into the temporal lobe. In temporal type, the proximal part of the superior temporal gyrus herniated into the lateral fronto-orbital gyrus. The variations of the Sylvian cisterns in 230 patients were as follows: in 31% (n = 71) Sylvian Type A, in 21% (n = 48) Sylvian Type B, in 34% (n = 78) Frontal Type, and in 14% (n = 33) Temporal Type.We concluded that venous perfusion disorder of the brain is the most important factor during the pterional approach. Careful intraoperative assessment and protection of the Sylvian vein, which is a surgical pitfall, is an indispensable part of the operation. The recognition of the anatomical variations of the Sylvian vein and cistern, and the detailed knowledge of the microvascular relationships at that level will allow the neurosurgeon to construct a better and safter microdissection plan, to save time and can prevent postoperative neurological deficits.     

Comparison of posterior approaches to the posterior incisural space: microsurgical anatomy and proposal of a new method,the occipital bi-transtentorial/falcine approach

OBJECTIVE: Direct surgical approaches to the posterior incisural space, including the pineal region, remain as challenges for neurosurgeons. The purposes of this study were 1) to compare the surgical views in the various posterior approaches to the posterior incisural space and 2) to propose a new approach, which is a modification of the occipital transtentorial approach. METHODS: Ten adult cadaveric specimens (20 sides) were studied, using x3 to x40 magnification, after perfusion of the arteries and veins with colored silicone. Intraoperative views in the posterior approaches to lesions were examined in stepwise dissections. In addition, the efficacy of the occipital bi-transtentorial/falcine approach was studied. RESULTS: The posterior incisural space has a roof, a floor, and anterior and lateral walls and extends backward to the level of the tentorial apex. The operative views defined by each approach differ in the extent to which they allow observation of the anatomic structures in the posterior incisural space. The occipital bi-transtentorial/falcine approach permits better observation of the contralateral half of the quadrigeminal cistern. CONCLUSION: Precise surgical anatomic knowledge of each approach is required for the treatment of lesions in the posterior incisural space, because the operative fields obtained with different approaches differ significantly. The occipital bi-transtentorial/falcine approach provides greater contralateral exposure of the posterior incisural space than does the occipital transtentorial approach.     

MSCT诊断成人永存镰状窦6例及文献回顾

目的分析成人永存镰状窦的多排螺旋CT表现,提高对大脑深静脉发育异常的进一步认识。方法选取6例经CTA诊断为永存镰状窦的成人患者,采用MSCT重组技术对其静脉成像进行分析。结果 6例患者均因临床疑诊颅内动脉病变而接受CTA检查。静脉期见大脑大静脉或直窦前部与上矢状窦后2/3相连的条带状血管样结构,未合并其他动静脉异常。结论成人永存镰状窦可不合并其他先天性静脉窦发育异常及阻塞,多排螺旋CTA是其无创、有效的检查方法。     

Falcine venous plexus within the falx cerebri: anatomical and scanning electron microscopic findings and clinical significance

Background

Only limited attention has been paid to the anatomy and clinical importance of the falcine venous plexus. The aim of this study was to evaluate the falcine venous plexus anatomically using scanning electron microscopy (SEM), and to provide guidance for neurosurgical approaches.

Methods

Latex or ink was injected into the superior and inferior sagittal sinus. The falcine venous plexus lying within the connective tissue of the falx cerebri was observed by dividing the falx into thirds (anterior, middle and posterior). Further, the SEM appearance of the falcine venous plexus was evaluated.

Results

The anterior third of the falx cerebri consisted of small diameter falcine venous vessels. These vessels were localized close to either the superior or inferior sagittal sinus, and none extended as far as mid-falx cerebri levels in any of the 16 cases. They communicated with either superior or inferior sagittal sinuses, but not with both of these sinuses. In the middle third of the falx cerebri, the majority of the vessels of the falcine venous plexus had larger diameter compared to those of the anterior third. These vessels extended the length of the falx cerebri levels. They communicated with both superior and inferior sagittal sinuses. In the posterior third of the falx cerebri, the vessels of the falcine venous plexuses had the largest diameter and were located at the junction of the inferior sagittal sinus and the straight sinus. They were localized at the lower two-thirds of the falx cerebri. In all cases, the dense venous networks communicated with the inferior sagittal sinus but not with the superior sagittal sinus. The falcine venous plexus observed in the posterior third of the falx cerebri was denser than in the anterior and middle portions. The SEM revealed small vessels whose diameter ranged between 42 and 138 μm. The vessels of the falcine venous plexus in the anterior third had a mean diameter of 0.42?±?0.1 mm, in the middle third a mean diameter of 0.87?±?0.17 mm, and in the posterior third, 1.38?±?0.21 mm.

Conclusion

The falcine venous plexus is a network of venous channels that exists within the connective tissue of the falx; the sizes and patterns of communication of these structures showed regional differences. Neurosurgeons should be aware of the regional differences when making an incision or puncturing the falx during a surgical approach.     

Aneurysms of the vein of Galen. Angiographic study and morphogenetic considerations

The angiographic and/or anatomic study of a series of 30 cases of Vein of Galen aneurysm (which is defined as an arterio-venous fistula within the wall of the vein of Galen itself, therefore as a purely extra cerebral lesion) permits the analysis of the afferent arteries, of the efferent veins, and of the aneurysmal sac itself. The examination of the afferent arteries confirms the data from the literature, indicating that most often it consists of the abnormal hypertrophy of otherwise normally organized arteries, including the dural arteries. In particular, the involvement of distal subcallosal branches of the anterior cerebral arteries as well as the arterio-arterial maze extending above the collicular plate, fit well the normal anatomy. The venous side of the malformation nevertheless presents with more unusual features; the most striking is the non-opacification of the straight sinus and/or part of the transverse sinuses in half of the cases; also, an aberrant falcine sinus is frequently observed, which actually represents the persistence of a normal channel in the fetal anatomy. A more complex pattern was observed in two cases in which the aneurysmal sac drained into the straight sinus via a loop made of a falcine sinus, the superior sagittal sinus and then backward through a second falcine sinus. Finally, from the systematization of the afferents arteries, the aneurysmal sac appears to belong both to the (prosencephalic) velum interpositum and to the ambient cistern. Such a vessel cannot be either the true vein of Galen or an internal cerebral vein; therefore it has to be a persistent fetal vein, the median prosencephalic vein, which drains the choroid plexuses of the lateral and third ventricles between the 7th and 12th weeks, and disappears normally to be replaced by the internal cerebral veins, when the intrinsic vascularization of the neural tube develops. The adult pattern of the brain artery being attained during the 8th week, the event that led to the arterio venous fistula should have occurred some time during the 3rd month. Unfortunately, no clue was found to orient to a specific cause for the anomaly. The frequently observed venous occlusions are actually not seen in neonates but rather in older children. This, and the fact that spontaneous thromboses within the malformative veins have been observed in vivo, make likely the conclusion that venous occlusions are a secondary phenomenon only.     

Étude anatomique du drainage des veines corticales inférieures dans le sinus transverse

Introduction

The cerebral venous system is poorly known and is best appreciated based on macroscopic anatomical considerations. We present an anatomical and immunohistochemical study to better define the morphological characteristics of the junction between the inferior cortical veins and the transversal sinuses.

Material and methods

Sixteen cadaveric specimens from the anatomy laboratory of the University Victor-Segalen of Bordeaux were studied. The venous junctions with the transversal sinuses were observed under the operating microscope. Thirty vein-sinus junctions were immunohistochemically stained with smooth muscle actin. Ten venous junctions were observed under the electronic microscope.

Results

The inferior cortical veins drain into the transverse sinus either directly or through a tentorial sinus. The venous orifices in the transverse sinuses share the same characteristics. They are oval with semicircular superior dural reinforcement and follow an orientation opposite venous flow in the transversal sinus. The histologic study showed that the walls of the cortical veins contained smooth muscle cells as well as the dural reinforcement of the transversal sinuses.

Conclusion

The venous orifices of the inferior cortical veins have the anatomical features of true sphincters. Their function in the regulation of the cerebral blood flow needs further exploration.     

Transarterial intravenous coil embolization of dural arteriovenous fistula involving the superior sagittal sinus

BACKGROUND

We report a rare case of traumatic dural arteriovenous fistula involving the superior sagittal sinus successfully treated by transarterial intravenous coil embolization.

CASE PRESENTATION

A 38-year-old woman presented with tension headache. She had a past history of severe head injury at the age of three. Computed tomography scanning showed a heterogenous low-density area in the right frontal lobe, and magnetic resonance imaging demonstrated abnormal vascular structures in the same area. Angiography revealed a dural arteriovenous fistula involving the lateral wall of the fully patent superior sagittal sinus. The fistula was fed by scalp, meningeal, and cortical arteries, and drained into a cortical vein leading to the superior sagittal sinus. Femoral transarterial intravenous embolization with microcoils completely occluded the dural arteriovenous fistula.

CONCLUSION

Severe head injury may lead to asymptomatic dural arteriovenous fistulas after a long time. Transarterial intravenous coil embolization can be effective in the treatment of dural arteriovenous fistulas involving the superior sagittal sinus.