INTRODUCTION
Dural sinus malformation (DSM) is a rare vascular anomaly characterized by venous lakes and abnormal connections between dural sinuses and cerebral veins, typically diagnosed in neonates and infants. Prognosis depends on subtype, timing of diagnosis, and complications like thrombosis or hydrocephalus, with torcular DSM (tDSM) mortality rates ranging from 22–41% [1-3]. High-flow fistulas cause venous hypertension and hydrocephalus, driven by arterial feeders such as the external carotid artery (ECA) [3,4]. Treatment involves multi-staged endovascular embolization, addressing residual shunts while avoiding complications [2,5]. This case report highlights the pressure cooker technique (PCT) in tDSM embolization, following CARE guidelines (for CAse REports) [6].
CASE REPORT
Initial Presentation
A child under the age of 1 year presented with macrocrania, facial vein dilation, hydrocephalus, and psychomotor delays. Imaging revealed a giant tDSM with high-flow fistulas, leading to progressive venous hypertension and neurodevelopmental complications. The child was treated at that time with 3 staged embolization procedures. The first 2 procedures were transarterial approaches, initially via the left ECA, followed by a second stage in the right ECA using liquid embolics in both cases. The third stage employed a dual access approach combining transarterial embolization through the posterior meningeal artery with venous embolization using a Copernic balloon at the torcula. Despite these attempts, the patient exhibited persistent residual malformation and symptoms of venous hypertension and hydrocephalus, necessitating further intervention. Detailed imaging (Fig. 1A–C), including with CT angiography revealed marked torcular dilation with extensive venous lakes and multiple arterial feeders contributing to a high-flow shunt. The feeders arose from the posterior cerebral artery (PCA), superior cerebellar artery (SCA), and branches of the ECA. Digital subtraction angiography (DSA) further delineated the anatomy, showing rapid shunting into the torcular pouch with retrograde venous flow contributing to venous hypertension. DSA provided crucial insight into the spatial relationships between feeders, the torcular pouch, and the draining veins, which informed the planning of the redo embolization.
Redo Embolization
Under general anesthesia, the procedure was performed with induced hypotension during PCT (systolic BP 60 mmHg for 30–60 minutes) and anticoagulation (activated clotting time of 60–80 seconds). Access was obtained through both femoral arteries (6 Fr) and both femoral veins (8 Fr). A 6 Fr CHAPERON guide catheter (MicroVention) was placed in the left vertebral artery and internal carotid artery for selective angiography to visualize feeders and venous outflow of the malformation. Once visualized, two 8 Fr Neuron Max guide catheters (Penumbra) were introduced into the venous system for retrograde microcatheterization of the main outflow vein. Through each 8 Fr guide, 2 detachable-tip SONIC 1.2 microcatheters (Balt) and 2 HEADWAY DUO (MicroVention) microcatheters were positioned for plug creation and embolic delivery. The first detachable tip microcatheter SONIC 1.2 was placed in the main outflow vein at the merging point of the primary veins. The second microcatheter SONIC 1.2 was also navigated and placed at the same level of the first microcatheter site, under the sheeping technique [7]. Under roadmap guidance, 2 HEADWAY DUO microcatheters were positioned at the shunt. The HEADWAY DUO microcatheters were used to deliver 12 coils to achieve a good density anti-reflux plug, followed by n-butyl-2-cyanoacrylate (nBCA) injection (Guerbet). Then, through the SONIC 1.2 microcatheters, Squid 12® (Balt) was subsequently delivered (14 vials) for shunt occlusion, achieving near-complete embolization of the tDSM (Fig. 2). Immediate post-procedure angiography confirmed substantial occlusion (Fig. 1D–F). The patient’s recovery was closely monitored, beginning with a 3-day stay in the intensive care unit and 10 days of parenteral anticoagulation, followed by transfer to a general care unit. Follow-up MRI at 10 days post-procedure showed partial thrombosis without ischemia or hemorrhage (Fig. 1G). Five months later, repeat DSA confirmed further venous remodeling with near-complete occlusion (Fig. 1H). Clinically, the patient demonstrated significant improvement in gait, speech, and visual function during rehabilitation.
DISCUSSION
High-flow fistulas in tDSM are associated with significant hemodynamic stress, contributing to complications such as venous hypertension, progressive hydrocephalus, and developmental delays [1-3]. The abnormal shunting creates high-pressure venous flow that may disrupt the delicate equilibrium required for normal cerebrospinal fluid dynamics, worsening hydrocephalus and venous congestion. These high-flow dynamics are driven by arterial feeders from vessels such as the ECA, PCA, and SCA, which create abnormal shunting into the venous system [3,4]. A proposed grading system classifies tDSM into 5 categories based on diagnosis timing, thrombosis, brain damage, feeders, and hydrocephalus. Antenatally diagnosed types include I, II, and IVa, while postnatally diagnosed types include III and IVb [1].
Management of tDSM can involve arterial, venous, or combined approaches [2,8]. The choice depends on the anatomy of the feeders, accessibility, and flow dynamics of the malformation. Arterial embolization is often the first-line approach for large, accessible feeders, as it allows for precise targeting of the fistula. However, in cases where feeders are small, tortuous, or inaccessible, a venous approach becomes essential. The PCT, initially developed [9-11] for arteriovenous malformations and dural arteriovenous fistulas, offers a novel approach for controlling reflux during embolization. By combining a proximal anti-reflux plug (formed by coils, glue, or both) with high-pressure delivery of liquid embolic agents, PCT ensures targeted occlusion of the fistula while minimizing risks to adjacent vasculature [9,11]. The retrograde transvenous PCT used in this case capitalized on the venous anatomy, enabling controlled embolization directly at the shunt. While venous approaches are technically more complex, they provide a crucial alternative in cases where arterial access alone is insufficient or unsafe. In this case, the use of coils and nBCA to form the plug minimized reflux risk, while subsequent delivery of Squid 12® ensured deep penetration into the fistula. This sequential approach not only maximized the therapeutic effect but also reduced the risk of embolic migration into adjacent vessels [9,12].
The selection of embolic agents plays a critical role in achieving successful occlusion. Common agents include Onyx® (Medtronic), PHIL® (MicroVention), nBCA, and Squid® [13]. Squid 12®, chosen for this case, has specific advantages over older agents, including lower viscosity, improved penetration into fine vessels, and enhanced radiopacity [13]. Its reduced imaging artifacts facilitated accurate visualization of the embolization process, which is critical in multi-lobed or high-flow malformations where non-target embolization could lead to complications. Additionally, the use of detachable-tip microcatheters, such as SONIC, provides greater control during embolic delivery, further reducing risks associated with reflux or non-target embolization [14].
Another key consideration in this case was the use of controlled hypotension [15]. Induced hypotension during the procedure reduced the flow rate through the fistula, creating a more favorable environment for embolization. However, this strategy requires careful monitoring to avoid complications such as ischemia or neurological deficits. In this case, maintaining a systolic blood pressure of 60 mmHg for 30–60 minutes, combined with anticoagulation, ensured procedural safety without compromising the patient’s recovery.
The treatment achieved significant clinical improvement, with near-complete occlusion and substantial symptom relief. However, small residual areas remained, reflecting the inherent challenge of completely occluding high-flow malformations without jeopardizing surrounding structures. Residual malformations often arise from the difficulty in achieving complete penetration of embolic agents into every feeder in high-flow systems, particularly in redo scenarios where scarring and altered anatomy add to the complexity [16]. This case contributes to the growing body of evidence supporting PCT as a versatile technique for high-flow malformations, especially in redo interventions.
DSM is a rare vascular anomaly causing venous hypertension and hydrocephalus. A redo embolization using the PCT achieved near-complete occlusion of a torcular DSM, improving symptoms. This case demonstrates the PCT’s efficacy in managing complex pediatric cases requiring multi-stage interventions.
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