Application of the Woven EndoBridge Device in the Treatment of Multiple Aneurysms of the Distal Posterior Cerebral Artery: A Case Report
Article information
Abstract
The Woven EndoBridge (WEB) device has emerged as a promising alternative to endovascular coiling. This case report demonstrates the use of stent-assisted WEB deployment for the embolization of multiple wide-neck posterior cerebral artery (PCA) aneurysms. A middle-aged patient was diagnosed with 3 unruptured aneurysms in the P3 and P4 segments of the right PCA, with sizes ranging from 2.5 mm to 6.6 mm. Given the small vessel diameter and distal location of the aneurysms, a combined approach was adopted. Coil embolization was performed for the most distal aneurysm, while stent-assisted WEB deployment was used for the proximal and middle aneurysms. The “flower bud” technique facilitated the safe positioning of the WEB device in challenging anatomical conditions. The procedure was successfully completed without complications, and the patient was discharged on postoperative day 7 with no neurological deficits. Follow-up at 3 months confirmed adequate embolization of all aneurysms, with in-stent stenosis managed conservatively.
INTRODUCTION
The Woven EndoBridge (WEB; MicroVention) provides an alternative to endovascular coiling and has demonstrated considerable efficacy in treating small- and medium-sized wide-neck bifurcation intracranial aneurysms. It functions by inducing flow disruption, thrombosis, and the formation of neointimal tissue through its braided, self-expanding mesh composed of nitinol wires with a platinum core [1]. Several large meta-analyses support the effectiveness of the WEB device in managing intracranial aneurysms [2]. In this case report, we describe the use of stent-assisted WEB deployment for the embolization of a wide-neck posterior cerebral artery (PCA) aneurysms.
CASE REPORT
A middle-aged female was diagnosed with multiple right PCA aneurysms. The patient was premedicated with aspirin and prasugrel in preparation for the endovascular procedure. On digital subtraction angiography (DSA), there were 3 aneurysms of the PCA and the diameter of the PCA was 1.61 mm in the proximal segment and 1.29 mm in the distal segment. From the proximal side, the size of the first aneurysm was 2.5×3.3×4.0 mm. The size of the second aneurysm was 4.7×6.6×6.5 mm. The size of the third aneurysm was 2.7×2.7×3.0 mm (Fig. 1).
Frontal and lateral digital subtraction angiography images showing 3 aneurysms located in the P3 and P4 segments (A, B). Targeted view of the 3 aneurysms after 3D reconstruction on the Canon Alphenix angiographic system (C). Postoperative image showing the stent and 2 WEB devices (D). The most distal aneurysm after embolization with coils (E). Final intraoperative image with fusion imaging of angiography and deployed devices. The brown color represents coils; the green color highlights the markers at both ends of the stent, with partial visualization of the stent itself; and the blue color indicates 2 WEB devices (F). Three-month follow-up frontal and lateral views show embolized aneurysms with 50% in-stent stenosis (G–I).
Under General anesthesia, a 4 Fr short sheath was inserted into the right radial artery under ultrasound guidance, as puncturing the distal radial artery proved challenging due to its small diameter. To prevent spasm, 100 µg of nitroglycerine was administered through the sheath, and imaging confirmed there was no vascular damage. Subsequently, a 7 Fr Glide sheath (Terumo Neuro) was changed. A 5 Fr 95 cm RIST (Medtronic) catheter was navigated to the right vertebral artery at the craniocervical junction.
Pre-angiographic and rotational imaging revealed 3 aneurysms in the P3 to P4 segment of the right PCA, each with thin branches originating from the neck. The dome-to-neck ratio for all aneurysms was less than 2. The goal was to embolize firstly the most distal aneurysm. A Guidepost 130 cm (Tokai Medical) was advanced to the right P2 segment, through which a Phenom17 (Medtronic) J catheter over a Synchro standard (Stryker) guidewire was inserted into the distal aneurysm, and coil embolization was performed. A frame was constructed using Tetra 2.5 mmx4.5 cm (Stryker) coils to avoid occluding small-diameter branches, and filling was completed using Tetra 1.5 mmx2.0 cm (Stryker) coils. Placement of Avenir 1 mmx2.0 cm (Wallaby Medical) coils was challenging. The procedure was completed with modified Montreal scale class 2.
Next, a decision was made to deploy a WEB device in the middle aneurysm. A manually J-shaped Headway 21 (Terumo Neuro) catheter was advanced into the aneurysm, and a WEB SL 7x3 (Terumo Neuro) device was deployed. The device was successfully positioned within the aneurysm, with no herniation into the parent vessel. For the proximal aneurysm, a manually J-shaped VIA 21 (Terumo Neuro) catheter was advanced into the aneurysm (since deploying a WEB SLS 4 via the Headway 21 was difficult), and a WEB SLS 4 (Terumo Neuro) was deployed. Although the device was positioned successfully, the WEB mesh herniated into the parent vessel by approximately 50%. Both WEB devices deployed using “flower bud” technique.
Therefore, a Neuroform Atlas 3.0×21 mm (Stryker) stent was deployed to cover the necks of the proximal and middle aneurysms, ensuring an adequate margin. Imaging confirmed that all aneurysms were successfully embolized and that the distal vessels were preserved.
Dyna CT confirmed that both the WEB device and stent were well opposed. Compressive hemostasis was achieved at the puncture site using a TR band (Terumo Medical).
No complications were observed in the postoperative period. The patient was discharged without neurological deterioration on the seventh day after the surgery. On the follow-up DSA at 3 months, all 3 aneurysms were successfully embolized with the stent in place. In-stent stenosis, due to intimal hyperplasia, of up to 50% was observed at the mid-section of the stent (Fig. 1). A decision was made to leave the patient on dual antiplatelet therapy for an additional 6 months, and intimal hyperplasia inside stent should resolve naturally. Neurologically, the patient showed no deterioration.
The operative video for this case is presented in Supplementary Video 1.
DISCUSSION
The use of the WEB device is feasible, even in smaller-caliber distal cerebral vessels. Its lower risk of periprocedural aneurysm rupture [3] made it the preferred choice in our case. However, for distal PCA aneurysms, achieving microcatheter stability can be challenging. Considering the higher recanalization rates associated with coiling, we prefer using the WEB device in appropriate cases because of its lower retreatment rates and better neurological outcomes [4]. In certain situations, the use of flow-diverting stents or double-layer braided stents may also be considered. Parent vessel occlusion is another potential option, though Jabeen et al. [5] reported that occlusion of the parent vessel for PCA aneurysms resulted in PCA territory infarction in 5 out of 16 patients, indicating a higher risk of ischemic complications.
A comprehensive meta-analysis on WEB, which included data from multiple major prospective studies, reported an overall periprocedural complication rate of 14%, with thromboembolic events being the most common. The WEB device was successfully deployed in 97% of patients, achieving adequate aneurysm occlusion in 81% of cases [6]. The 12-month findings of the WEB-IT trial showed a complete aneurysm occlusion rate of 53.8%, with 84.6% of aneurysms achieving adequate occlusion [7]. Additionally, studies have described the use of the WEB device in conjunction with stent assistance within the parent vessel [8].
In cases where aneurysms present with significant misalignment, deploying the WEB device can be challenging. To address this, we employed the “flower bud” technique previously described by our clinic [9]. This method involves making flower bud shaping in the neck and then pushing the WEB device to ensure proper positioning within the aneurysm.
To safely perform the “flower bud” technique, system stability is essential, and the use of an intermediate catheter plays a crucial role. In our case, a 0.043-inch Guidepost 130 cm catheter facilitated the procedure. Intermediate catheters are particularly important in cases with significant misalignment between the parent vessel and the aneurysm, such as in proximal and middle PCA aneurysms. Although low-profile intermediate catheters like VECTA46 (Stryker) and Phenom Plus (Medtronic) are available, we selected a narrower-diameter Guidepost 130 cm catheter to navigate as close as possible to the aneurysm in the small parent artery.
Another factor to consider when deploying the WEB device in PCA aneurysms is the stiffness of the VIA Plus (Medtronic) catheter, which can make navigation in the PCA more difficult. The vessel’s tortuosity and the indirect course of the vessel leading to the aneurysm further increased the risk of aneurysm wall perforation with the stiff catheter. In our case, the use of a softer catheter for the middle aneurysm, such as the Headway 21, facilitated safe navigation in the tortuous PCA, reducing the risk of vessel injury, which made it more suitable for this procedure. However, for the proximal aneurysm, the VIA21 (Medtronic) catheter was used because loading small-sized WEB devices, such as WEB SLS 4, into the Headway 21 catheter may not be feasible due to differences in catheter hub design. The CLEVER study [10] demonstrated the effective use of the WEB 17 (Terumo Neuro) device in treating intracranial aneurysms, which can be deployed via a 0.017-inch microcatheter. However, at the time of the procedure, this device had not yet been approved for clinical use in Japan.
Studies have shown that stent assistance is feasible with the WEB device and is more commonly applied in sidewall aneurysms [11]. However, in vessels with smaller diameters, even minor protrusion of the WEB device mesh into the lumen of an artery can lead to complications, such as arterial occlusion. While the proximal marker of the WEB device within the parent artery does not significantly increase thrombotic risk, the mesh components of the WEB device can be highly thrombogenic if they protrude into the parent vessel. It is worth noting that the Neuroform Atlas stent has a higher radial force compared to the WEB device. Therefore, we recommend using stents with higher radial force to ensure vessel patency. On the other hand, in our case, if the WEB 17 device could be used for the most proximal aneurysm, such as the SL 4/2 or 3.5/2, stent assistance and post dual antiplatelet therapy might not be needed. Follow-up angiography is recommended 3 months after treatment. If the aneurysm remains unembolized, a follow-up DSA should be conducted at 6 months.
Overall, considering the ease of use of the intrasaccular flow-diverting device, it holds promise for the future development of endovascular surgery for posterior circulation aneurysms. Additionally, in cases with a wide neck, the use of an intrasaccular device with stent assistance is also possible.
SUPPLEMENTARY MATERIALS
Supplementary materials related to this article can be found online at https://doi.org/10.5469/neuroint.2025.00080.
The operative technique demonstration of the illustrative case.
Notes
Fund
None.
Ethics Statement
This case report was obtained Institutional Review Board (IRB) of the Fujita Health University (IRB no.: HM24-275). Consent for the publication of the patient’s data was obtained upon admission
Conflicts of Interest
The authors have no conflicts to disclose.
Author Contributions
Concept and design: JT and IN. Analysis and interpretation: AZ. Data collection: JT. Writing the article: AZ and JT. Critical revision of the article: JT, IN, and MB. Final approval of the article: YK. Overall responsibility: AZ and JT.