Venous Anatomy Research Articles

Foundations of the Diagnosis and Management of Idiopathic Intracranial Hypertension and Pulsatile Tinnitus

Venous sinus stenosis has garnered increasing academic attention as a potential etiology of idiopathic intracranial hypertension (IIH) and pulsatile tinnitus (PT). The complex anatomy of the cerebral venous sinuses and veins plays a crucial role in the pathophysiology of these conditions. Venous sinus stenosis, often found in the superior sagittal or transverse sinus, can lead to elevated intracranial pressure (ICP) and characteristic IIH symptoms. Stenosis, variations in dural venous anatomy, and flow dominance patterns contribute to aberrant flow and subsequent PT. Accurate imaging plays a vital role in diagnosis, and magnetic resonance (MR) venography is particularly useful for detecting stenosis. Management strategies for IIH and PT focus on treating the underlying disease, weight management, medical interventions, and, in severe cases, surgical or endovascular procedures. Recently, venous sinus stenting has gained interest as a minimally invasive treatment option for IIH and PT. Stenting addresses venous sinus stenosis, breaking the feedback loop between elevated ICP and stenosis, thus reducing ICP and promoting cerebrospinal fluid outflow. The correction and resolution of flow aberrances can also mitigate or resolve PT symptoms. While venous sinus stenting remains an emerging field, initial results are promising. Further research is needed to refine patient selection criteria and evaluate the long-term efficacy of stenting as compared to traditional treatments.

Challenges in the use of Venous Sinus Stenting in the Treatment of Idiopathic Intracranial Hypertension and Pulsatile Tinnitus

Although numerous case series and meta-analyses have shown the efficacy of venous sinus stenting (VSS) in the treatment of idiopathic intracranial hypertension and idiopathic intracranial hypertension-associated pulsatile tinnitus, there remain numerous challenges to be resolved. There is no widespread agreement on candidacy; pressure gradient and failed medical treatment are common indications, but not all clinicians require medical refractoriness as a criterion. Venous manometry, venography, and cerebral angiography are essential tools for patient assessment, but again disagreements exist regarding the best, or most appropriate, diagnostic imaging choice. Challenges with the VSS technique also exist, such as stent choice and deployment. There are considerations regarding postprocedural balloon angioplasty and pharmacologic treatment, but there is insufficient evidence to formalize postoperative decision making. Although complications of VSS are relatively rare, they include in-stent stenosis, hemorrhage, and subdural hematoma, and the learning curve for VSS presents specific challenges in navigating venous anatomy, emphasizing the need for wider availability of high-quality training. Recurrence of symptoms, particularly stent-adjacent stenosis, poses challenges, and although restenting and cerebrospinal fluid-diverting procedures are options, there is a need for clearer criteria for retreatment strategies. Despite these challenges, when comparing VSS with traditional cerebrospinal fluid-diverting procedures, VSS emerges as a favorable option, with strong clinical outcomes, lower complication rates, and cost-effectiveness. Further research is necessary to refine techniques and indications and address specific aspects of VSS to overcome these challenges.

Are hemodynamics responsible for inflammatory changes in venous vessel walls? A quantitative study of wall-enhancing intracranial arteriovenous malformation draining veins.

Signal enhancement of vascular walls on vessel wall MRI might be a biomarker for inflammation. It has been theorized that contrast enhancement on vessel wall imaging (VWI) in draining veins of intracranial arteriovenous malformations (AVMs) may be associated with disease progression and development of venous stenosis. The aim of this study was to investigate the relationship between vessel wall enhancement and hemodynamic stressors along AVM draining veins. Eight AVM patients with 15 draining veins visualized on VWI were included. Based on MR venography data, patient-specific 3D surface models of the venous anatomy distal to the nidus were segmented. The enhanced vascular wall regions were manually extracted and mapped onto the venous surface models after registration of image data. Using image-based blood flow simulations applying patient-specific boundary conditions based on phase-contrast quantitative MR angiography, hemodynamics were investigated in the enhanced vasculature. For the shear-related parameters, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated. Velocity, oscillatory velocity index (OVI), and vorticity were extracted for the intraluminal flow-related hemodynamics. Visual observations demonstrated overlap of enhancement with local lower shear stresses resulting from decreased velocities. Thus, higher RRT values were measured in the enhanced areas. Furthermore, nonenhancing draining veins showed on average slightly higher flow velocities and TAWSS. Significant decreases of 55% (p = 0.03) for TAWSS and of 24% (p = 0.03) for vorticity were identified in enhanced areas compared with near distal and proximal domains. Velocity magnitude in the enhanced region showed a nonsignificant decrease of 14% (p = 0.06). Furthermore, increases were present in the OSI (32%, p = 0.3), RRT (25%, p = 0.15), and OVI (26%, p = 0.3) in enhanced vessel sections, although the differences were not significant. This novel multimodal investigation of hemodynamics in AVM draining veins allows for precise prediction of occurring shear- and flow-related phenomena in enhanced vessel walls. These findings may suggest low shear to be a local predisposing factor for venous stenosis in AVMs.

Vertebral Artery Mobilization During Transcondylar Extreme Far Lateral Approach for Excision of Large Foramen Magnum Meningioma: 2-Dimensional Operative Video.

Foramen magnum meningiomas are challenging lesions owing to their proximity to the lower brainstem, vertebrobasilar system, and lower cranial nerves.1,2 Tumor size, origin, morphology, relationship to neurovascular structures, and bony anatomy determine the optimal surgical approach.2,3 Classically, far lateral approaches have been the workhorse approach to the foramen magnum. Variations of the far lateral including transcondylar and extended transcondylar (paracondylar), with or without transposition of the vertebral artery, are sometimes used for a more lateral approach to the brainstem and clivus. Here, we present a 60-year-old male patient presenting with a large foramen magnum meningioma. Preoperative workup includes computed tomography and MRI with angiography to assess for posterior circulation dominance, anatomic variants including posterior inferior cerebellar artery origin, venous, and bony anatomy.1,4 An extreme far lateral provides access anterior to the vertebral artery to extend exposure beyond the standard far lateral approach. This comprised transcondylar drilling, bony mobilization of the V3 Vertebral artery from C1 foramen transversarium, and dural mobilization of vertebral artery with a dural cuff at its site of dural entry. The patient tolerated the procedure, gross total resection was achieved, and the patient was discharged home. This video demonstrates in detail the steps of exposure, condylar drilling, vertebral artery transposition, and dural opening. These maneuvers can be difficult to conceptualize yet are key to successful extended transcondylar exposure. The patient gave informed consent for surgery and video recording. Institutional Review Board approval was deemed unnecessary.

Beyond the microcirculation: sequestration of infected red blood cells and reduced flow in large draining veins in experimental cerebral malaria.

Sequestration of infected red blood cells (iRBCs) in the microcirculation is a hallmark of cerebral malaria (CM) in post-mortem human brains. It remains controversial how this might be linked to the different disease manifestations, in particular brain swelling leading to brain herniation and death. The main hypotheses focus on iRBC-triggered inflammation and mechanical obstruction of blood flow. Here, we test these hypotheses using murine models of experimental CM (ECM), SPECT-imaging of radiolabeled iRBCs and cerebral perfusion, MR-angiography, q-PCR, and immunohistochemistry. We show that iRBC accumulation and reduced flow precede inflammation. Unexpectedly, we find that iRBCs accumulate not only in the microcirculation but also in large draining veins and sinuses, particularly at the rostral confluence. We identify two parallel venous streams from the superior sagittal sinus that open into the rostral rhinal veins and are partially connected to infected skull bone marrow. The flow in these vessels is reduced early, and the spatial patterns of pathology correspond to venous drainage territories. Our data suggest that venous efflux reductions downstream of the microcirculation are causally linked to ECM pathology, and that the different spatiotemporal patterns of edema development in mice and humans could be related to anatomical differences in venous anatomy.

Direct superior sagittal sinus puncture via a surgical burr hole for curative embolization of the complex transverse-sigmoid sinus dural arteriovenous fistula: How I do it.

Transvenous embolization of high-grade dural arteriovenous fistulas (dAVFs) is challenging particularly when the direct sinus access is favorable due to the complex venous anatomy which prohibits endovascular access via the transfemoral approach. The procedure was conducted in the hybrid operating suite, where a burr hole was performed, followed by direct catheterization of the superior sagittal sinus. Coil embolization was then executed to achieve complete obliteration of the fistula. The direct puncture of the superior sagittal sinus is a safe and effective method for treating complex dAVFs. This approach grants access to the fistula channel which facilitates curative embolization.

Advanced Imaging Techniques Used in Direct Portosystemic Shunt Creation in Budd-Chiari Syndrome with Complex Venous Anatomy.

Imaging Features of Plantar Vein Thrombosis: An Easily Overlooked Condition in the Differential Diagnosis of Foot Pain.

Plantar vein thrombosis is a venous disorder affecting deep plantar veins that can manifest with non-specific localized pain, plantar foot pain, swelling, and sensation of fullness. Plantar veins are not routinely assessed during sonographic scans for deep venous thrombosis, which makes plantar venous thrombosis a commonly missed diagnosis. This paper provides a comprehensive review of the venous anatomy of the foot and imaging findings of plantar venous thrombosis as well as discusses the current literature on the topic and its differential diagnoses.

CT Findings of Azygos Venous System: Congenital Variants and Acquired Structural Changes.

The azygos venous system is a crucial conduit of the posterior thorax and potentially vital collateral pathway. However, it is often overlooked clinically and radiologically. This pictorial essay reviews the normal azygos venous anatomy and CT findings of congenital variations and structural changes associated with acquired pathologies.

Disparity in Stent Sizing for Iliac Vein Obstruction Measured by Intravascular Ultrasound and Venogram: A Retrospective Study at a Single Institution

Abstract Introduction: Accurately assessing the location, degree of stenosis, and size requirements for stenting, as well as delineating the venous anatomy to identify optimal landing zones, are crucial elements for achieving successful outcomes in deep venous stenting procedures. Aim: Is to compare and analyse the sizing of stents used in iliac vein obstruction, specifically between venography and IVUS (intravascular ultrasound) guidance. Materials and Methods: A review of retrospectively collected data at JIVAS between 2016 and 2023[the selected time frame was determined based on the comprehensive availability of data.]conducted on procedural data that were contemporaneously entered into an electronic medical records database for iliac vein stent placements, including attempted cases (N=26), for iliac vein obstruction. The analysis focused on 23 limbs from 23 patients. Out of these, 14 patients underwent stent placement guided by venography, while 9 patients had stent placement guided by intravascular ultrasound (IVUS). Three out of the 26 patients who were to undergo stenting based on Venography were not included since intraoperative IVUS revealed no evidence of compression. Results: The distribution of interventions showed that venography was employed in 61% of cases, while IVUS was used in 39% of cases. Regarding the etiology of the condition, 83% of cases were attributed to NIVL, 13% to NIVL+PTS, and 4.3% to PTS. The Stent length variable had a mean of 92.6 (with a standard deviation of 29.4) and a median of 80.0 [80.0; 110]. The range for Stent length spanned from 40.0 to 150. The median length of the intervention was significantly different between the two groups (p<0.01, Mann-Whitney test). Conclusion: The inclusion of intravascular ultrasound (IVUS) as a primary tool appears to influence the selection of stent lengths in the management of both thrombotic and non-thrombotic Iliac venous disease. The collective evidence underscores the multifaceted nature of iliac vein stenting, urging continued research and clinical exploration to refine strategies for optimal patient outcomes.

Techniques for portal vein targeting during a transjugular intrahepatic portosystemic shunt.

A transjugular intrahepatic portosystemic shunt (TIPS) is one of the most challenging procedures in interventional radiology. Hepatic and portal venous anatomy can be highly variable, and access to the portal vein, which can be quite difficult even for experienced surgeons, is the most critical step in a TIPS. Although there are multiple techniques to achieve a portal venous puncture, each access technique carries a unique set of risks and benefits. Thus, knowledge of these assistive techniques will add to the resources available to the surgeon when planning and subsequently performing a TIPS and, ultimately, increase the likelihood of a safe and successful procedure.

Usefulness of sectional images in dural AVF for the interpretation of venous anatomy.

Knowledge of the venous anatomy is essential for appropriately treating dural arteriovenous fistulas (AVFs). It is challenging to determine the overall venous structure despite performing selective angiography for dural AVFs with feeder from multiple selected arteries. This is because only a part of the veins can be observed through the shunt in the selected artery. Therefore, after performing selective angiography of all vessels to understand the approximate venous anatomy, the venous anatomy can be easily understood by closely examining the source image of computed tomographic angiography or magnetic resonance angiography. Through this, it is possible to specify the vein that is to be blocked (target embolization), thereby avoiding extensive blocking of the vein and avoiding various complications. In the case of dural AVF with feeder from single selected artery, if the multiplanar reconstruction image of the three-dimensional rotational computed tomography obtained by performing angiography is analyzed thoroughly, a shunted pouch can be identified. If embolization is performed by targeting this area, unnecessary sinus total packing can be avoided.

Functional Cerebral Venous Anatomy: A Perspective on Venous Collaterals Part II, Infratentorial Venous System

Abstract The infratentorial veins are densely packed in a smaller space compared to the supratentorial veins and have many variations, such as disconnections and anastomoses. Knowledge of the functional venous anatomy of the posterior fossa is becoming increasingly important in neurointerventional procedures. The basic brainstem veins are longitudinal and transverse veins. The venous drainage of the brainstem and cerebellum follows 3 paths: superior (Galenic), anterior (petrosal), and posterior (torcular). Knowledge of the basic venous anatomy of the brainstem and cerebellum is essential for understanding the routes and patterns of venous drainage under pathological conditions, particularly in arteriovenous shunts. This review describes posterior fossa venous development and the functional venous anatomy of the posterior fossa, mainly the veins of the brainstem, cerebellum, and the emissary veins.

Functional Cerebral Venous Anatomy from the Viewpoint of Venous Collaterals Part I, Supratentorial Superficial and Deep Venous System

Abstract Supratentorial veins are divided into superficial and deep venous systems. Most superficial veins drain into the superior sagittal sinus, cavernous sinus, transverse sinus, and inferior sagittal sinuses. Most deep veins drain into the internal cerebral vein, and some drain into the basal vein of Rosenthal, which head toward the great cerebral vein of Galen. The functional anatomy of the supratentorial cerebral veins can be explained by dividing them into (1) veins on the lateral surface of the cerebral hemisphere, (2) the basal vein of Rosenthal system, and (3) the internal cerebral vein system. Many anastomotic channels exist between the superficial venous systems, veins at the base of the brain, and transcerebral veins. To understand and prevent adverse neurointerventional effects, in this study, we review the cerebral venous anatomy from the viewpoint of venous collaterals.

Circular Configuration of Torcular Herophili Presenting as Childhood Headache: 2D Computational Fluid Dynamic Analysis with a Proposed Mechanism.

This case report presents a rare anatomical variant of the torcular Herophili, characterized by a circular configuration and the absence of the left transverse sinus. A 12-year-old child presented with intermittent holocranial headaches, and imaging revealed the circular torcular Herophili along with mild ventricular enlargement. The straight sinus drained into the left side of the circular torcular Herophili. Following lumbar puncture and cerebrospinal fluid (CSF) drainage, the child experienced symptom improvement. During a 6-month follow-up, the patient remained asymptomatic, without further headaches or academic disruptions. Similar to a previously reported case, the circular torcular Herophili with unilateral absent transverse sinus may be associated with impaired CSF absorption due to altered blood flow through abnormal venous anatomy. We performed two-dimensional computational fluid dynamic analysis of simulated flow through a synthetic model and showed that this circular configuration is associated with venous stasis. The venous stasis in the sinus may impair CSF absorption through the arachnoid granulations causing hydrocephalus and explaining the headache. Close monitoring and follow-up are recommended for patients with this variant. Further investigation is needed to better understand the clinical implications and underlying mechanisms of such torcular Herophili variations.

The influence of spinal venous blood pressure on cerebrospinal fluid pressure

In Alligator mississippiensis the spinal dura is surrounded by a venous sinus; pressure waves can propagate in the spinal venous blood, and these spinal venous pressures can be transmitted to the spinal cerebrospinal fluid (CSF). This study was designed to explore pressure transfer between the spinal venous blood and the spinal CSF. At rest the cardiac-related CSF pulsations are attenuated and delayed, while the ventilatory-related pulsations are amplified as they move from the spinal venous blood to the spinal CSF. Orthostatic gradients resulted in significant alterations of both cardiac- and ventilatory-related CSF pulsations. Manual lateral oscillations of the alligator’s tail created pressure waves in the spinal CSF that propagated, with slight attenuation but no delay, to the cranial CSF. Oscillatory pressure pulsations in the spinal CSF and venous blood had little influence on the underlying ventilatory pulsations, though the same oscillatory pulsations reduced the ventilatory- and increased the cardiac-related pulsations in the cranial CSF. In Alligator the spinal venous anatomy creates a more complex pressure relationship between the venous and CSF systems than has been described in humans.

Prevalence and Predictors of Venous Stenosis Following First Transvenous Cardiac Implantable Electronic Device Implantation.

Very few studies have been done on Venous stenosis following the first transvenous cardiac device implantation. We aimed to assess the prevalence and predictors of Venous stenosis/Occlusion following the first transvenous cardiac device implantation with venous angiography at one year of follow-up. This study was a single-center prospective, observational study. Demographic, clinical, procedural, and device data was collected. All patients underwent a preimplant contrast and repeated venography at twelve months to look for upper limb venous anatomy, obstruction, or collaterals. A total of 146 patients were included in the final analysis. 60 (41 %) patients developed some degree of venous stenosis. Most patients had mild to moderate stenosis, and almost all were asymptomatic. Among patient-related factors increasing age (64.66 ± 10.07 vs 60.91 ± 11.94 years p = 0.04), presence of hypertension (50.5 % vs 19.6 % p = 0.0004), diabetes (73 % vs 29.6 % p = 0.000) and dyslipidemia (66.7 % vs 36.3 p = 0.009) were significantly associated with Venous stenosis/occlusion. Among procedure-related factors, larger total lead diameter (3.88 ± 1.09 vs. 3.50 ± 1.03 mm p = 0.03) and implantation of biventricular devices (p = 0.0037) seem to be significantly associated with venous obstruction. In logistic regression analysis, hypertension (p = 0.018), total lead diameter (p = 0.024), and use of CRT-P/CRTD/ICD (p = 0.03) remained significant predictors of severe venous stenosis. Our study demonstrates venous obstruction in 40 % of cardiac implantable electronic device patients at one-year follow-up. Most patients have mild to moderate stenosis, and almost all are asymptomatic. Increasing age, hypertension, diabetes, dyslipidemia, larger total lead diameter, and implantation of biventricular devices are significantly associated with venous obstruction.

Transvenous embolization for an intraosseous clival arteriovenous fistula via a proper access route guiding a three-dimensional fusion image: illustrative case.

Intraosseous clival arteriovenous fistulas (AVFs), in which the shunt drains extracranially from the posterior and anterior condylar veins rather than from the cavernous sinus (CS), are rare. Targeting embolization of an intraosseous clival AVF is challenging because of its complex venous and skull base anatomy; therefore, a therapeutic strategy based on detailed preoperative radiological findings is required to achieve a favorable outcome. Here, the authors report the successful targeted embolization of an intraosseous clival AVF using an ingenious access route. A 74-year-old woman presented with left-sided visual impairment, oculomotor nerve palsy, and right facial pain. A fusion image of three-dimensional rotational angiography and cone-beam computed tomography revealed a left CS dural AVF and a right intraosseous clival AVF. The shunt flow of the clival AVF drained extracranially from the posterior and anterior condylar veins via the intraosseous venous route. Transvenous embolization was performed by devising suboccipital, posterior condylar, and intraosseous access routes. The symptoms resolved after the bilateral AVFs were treated. Accurate diagnosis and proper transvenous access based on detailed intraosseous and craniocervical venous information obtained from advanced imaging modalities are key to resolving intraosseous clival AVF.

Pterygoid venous plexus anastomosis in trigeminal percutaneous glycerol rhizotomy: illustrative case.

Percutaneous glycerol rhizotomy (PGR) is a common, effective, and relatively safe treatment for trigeminal neuralgia that is refractory to medical management. Anastomotic skull base venous anatomy should be considered when delivering percutaneous agents. The authors report an anastomotic connection, not previously described in the literature, between the bilateral pterygoid venous plexuses upon air injection during PGR with computed tomography (CT) guidance for trigeminal neuralgia. Pertinent microsurgical and skull base venous anatomy is reviewed. Anastomoses between the pterygoid venous plexuses present a potential passage for materials used during PGR to reach unintended contralateral neurovascular structures. The use of CT guidance may identify this anastomotic connection and decrease the likelihood of an aberrant flow of materials used during the PGR.

Venous anatomy of the superficial circumflex iliac artery perforator flap: A cadaveric and clinical study

Reconstructive surgeons frequently face challenges with free tissue transfer when transplanted flaps are thicker than intended. This is especially pronounced in lower limb cases, where the soft tissue below the knee is thin. The supra-fascial superficial circumflex iliac perforator (SCIP) flap overcomes this problem, but venous congestion remains a concern. We aim to examine the venous anatomy of the SCIP flap through cadaveric dissections and clinical data analyses to enhance the understanding of the venous anatomy and reduce venous congestion in future procedures. Eight cadaveric groins underwent venous dye injection and dissection to identify the superficial circumflex iliac vein (SCIV) and venae comitantes (VC) vascular networks. The venous anatomy was studied for dominant drainage. From April 2015 to December 2019, we conducted 102 SCIP flap reconstructions, mainly using the superficial circumflex iliac artery's superficial branch. Clinical data were analyzed and correlated with cadaveric dissections. SCIP flaps were categorized into three groups: dual drainage (VC and SCIV) in group I, SCIV-only in group II, and VC-only in group III. Correlations between clinical cases and cadaveric dissections revealed the SCIV as an independent drainage system with oscillating links to the VC. The SCIV is approximately twice the diameter of the VC, and the area of each vascular network suggests codominance. No significant difference in flap loss or venous congestion rates was noted when SCIV was the sole drainage, compared with VC or dual drainage. The SCIP flap with one artery and SCIV anastomosis, exhibits low venous congestion rates. Surgeons should consider SCIV for safe SCIP flap reconstruction.