Dislocation of a WEB Device into the Middle Cerebral Artery : Removal with the Alligator Retrieval Device

Management of WEB device migration and mal-position in endovascular treatment of cerebral aneurysms

With increasing advances in technology, the breadth of aneurysms that are treatable via an endovascular approach has increased. Wide necked aneurysms remain difficult to treat but the emergence of dedicated intrasaccular flow disruption devices such as the Woven EndoBridge (WEB, Micorvention) has increasingly seen previously ruptured and unruptured wide necked aneurysms successfully embolised and secured from the circulation using a single device.We are reporting two cases of WEB device treatment from the earliest experience with this device at our institution. These were complicated by partial extrusion in one case and remote migration of the WEB device in another case. Our initial cases highlight the importance of case selection and the need for accurate WEB sizing which are paramount to ensure complete occlusion of the aneurysm without complications of dislocation or extrusion into the parent vessel. Since then, we have performed over 170 cases with the WEB device. We also present a comprehensive review of the limited literature available on the management of mal-positioned and dislocated WEB devices. This allows us to reflect on how to avoid these complications and the different management options at the disposal of the neuro-interventionalist once such a complication has already occured. Rescue devices and manoeuvres that we reflect on include microcatheter manipulation, alligator retrieval device, stent retrievers, microsnares, aspiration, and stenting. Ultimately, each case needs to be individually evaluated and the best strategy selected depends on the context and specific circumstances.

The impact of pre-treatment aneurysm angulation. What happens with WEB devices at follow-up?

BACKGROUND

WEB shape modification has been analyzed in relation to the aneurysm occlusion outcome and techniques have been presented with one-dimensional measurements of the device to quantify the change after implantation. In this work, we present an analysis of pre-treatment vascular morphology and hemodynamics of cases treated with WEB devices, which were three-dimensionally quantified in morphology and position to detect modifications.

METHODS

Seventeen WEB-treated aneurysms with pre-treatment, post-treatment and follow-up 3D flat-panel CT were included. Three-dimensional measurements of the WEB morphology and position were made at post-treatment and at follow-up. Differences between acquisitions of all measured variables were statistically evaluated (Wilcoxon signed-rank paired test, P-value = 0.05). Pre-treatment aneurysm angles were three-dimensionally measured and CFD simulations were performed to evaluate the influence of flow on WEB changes.

RESULTS

WEB height and diameter presented statistically significant changes. Modification of the angle between the WEB axis and parent artery was significantly higher in the group with WEB shape modification (Mann-Whitney U test, P < 0.05). In this group, the median pre-treatment aneurysm angle was smaller than in the group without shape modification (8.16° vs. 13.14°, P = 0.06). Inflow ratio was higher in the WEB shape modification group.

CONCLUSIONS

An association between the magnitude of morphological changes of the WEB with the direction of its axis within the aneurysm was found. The analysis of pre-treatment morphological and hemodynamic conditions would allow the detection of aneurysm cases in which the WEB will undergo a more pronounced modification.

Bailout Technique for Protrusion and Migration of Detached Woven EndoBridge Devices with Amplatz Goose Neck Microsnare

Objective

The Woven EndoBridge (WEB; MicroVention TERUMO, Tustin, CA, USA) is an intrasaccular flow disruptor developed for the treatment of wide-neck bifurcation aneurysms (WNBA). While its safety and satisfactory mid- to long-term treatment outcomes have been documented, there have also been reports of complications such as WEB protrusion and migration. We encountered 3 cases in which the WEB protruded or migrated to the parent vessel after deployment, necessitating retrieval. In this report, we address the technical tips for retrieval techniques and factors associated with these complications, including a literature review.

Case Presentation

Of the 120 cases of our experience with WEB treatment for cerebral aneurysms for the period since January 2021, 3 required WEB retrievals. In 2 cases, significant WEB migration toward the parent vessel occurred while maneuvering the delivery microcatheter because of sticky detachment. In the remaining case, after detachment of the WEB, tilting occurred, leading to a strong protrusion into one of the branches, which prevented guiding the microcatheter for bailout stenting. In all cases, the proximal marker of the WEB was captured using an Amplatz Goose Neck Microsnare (Medtronic, Minneapolis, MN, USA) pulled back into the VIA catheter (the delivery catheter for the WEB; MicroVention TERUMO), and further into an intermediate catheter positioned as close to the aneurysm as possible, enabling uneventful retrieval.

Conclusion

None of the cases damaged the aneurysm or proximal parent vessel wall, and additional aneurysm occlusion treatment was performed. However, WEB protrusions and migration are rare. When retrieval is required, it is crucial to act swiftly owing to the risk of distal thrombosis from the lumen inside of the WEB. Therefore, recognizing Goose Neck Microsnare as a retrieval technique is valuable.

The impact of delivery technique on Woven EndoBridge deployment and detachment in an in vitro aneurysm model

BACKGROUND

The Woven EndoBridge (WEB) device is increasingly used for treatment of wide-neck bifurcation aneurysms. With the newer 17 system, WEB deployment has been associated with a phenomenon known as incomplete or "sticky" detachment from the delivery wire, which may lead to imprecise placement. Optimal techniques for WEB manipulation and delivery to avoid this problem are poorly defined. This study aimed to evaluate standard WEB deployment techniques and determine the impact of delivery techniques and WEB stickiness on procedural success.

METHODS

An in vitro study using identical silicone middle cerebral artery aneurysm models (n = 32) assessed WEB (6 × 2 mm) deployment through a VIA 17 microcatheter via three techniques that involved: "loading," "neutral," and "tension" on the pusher wire. Microcatheter position was placed in varied positions from the WEB device. Woven EndoBridge stickiness was graded during detachment attempts. Primary outcomes were detachment stickiness and attempt number, compared between techniques using Fisher's exact test.

RESULTS

The tension technique resulted in significantly fewer sticky detachments and detachment attempts compared to forward load or neutral techniques (p < 0.001). Sticky detachment was lower with tension (0% sticky) versus forward load (42% sticky, 8% very sticky) (p < 0.001). Forward load had a 50% rate of stickiness versus 0% with tension and neutral (p < 0.001). Forward load required multiple attempts in 100%, compared to 57% with neutral and 8% with tension (p < 0.001). Higher stickiness grades increased the need for multiple attempts (p < 0.001).

CONCLUSION

The tension technique reduces incomplete WEB detachment and enables precise single-attempt detachment, optimizing delivery precision. In vivo confirmation is needed.

Micro-snare retrieval as bail-out technique for a distally migrated WEB-device: A case report

Intra-procedural intrasaccular device migration is an uncommon complication of endovascular treatment of wide-neck aneurysms. We report the case of a 52-years old Caucasian male who presented with a 3 × 3 mm posterior facing top of the basilar aneurysm in which treatment with WEB-SL (Woven EndoBridge-single layer) device was tempted. Inadvertent WEB migration in the right posterior cerebral artery occurred after detachment. Two retrieval attempts were performed using a combined technique with two different stent-retrievers and a 5-Fr distal access catheter. Upon WEBectomy attempt, the device rolled over the stents, and the passages were unsuccessful. The device was successfully removed using a microSnare, catching and retrieving it inside the 5-Fr distal access catheter. Micro-Snare is an effective bail-out technique to recover migrated intrasaccular WEB devices in cerebral arteries.

Rescue Stenting for Inadvertent Branch Vessel Occlusion Following Cerebral Aneurysm Embolization With the Woven EndoBridge Device

Intrasaccular flow modification with devices like the Woven EndoBridge (WEB, MicroVention, Inc., Aliso Viejo, California, US) is an increasingly utilized endovascular treatment for bifurcation aneurysms. Among the potential complications of the procedure is branch vessel occlusion. There are no previous publications of rescue stenting for inadvertent branch vessel occlusion with the WEB device. We report two cases of rescue stenting following branch vessel occlusion after cerebral aneurysm embolization with the WEB device. In both cases, rescue stenting with a Neuroform Atlas stent Stryker, Fremont, CA, US) successfully revascularized the occluded vessel and led to good patient outcomes.

Microsnare retrieval as a bail-out technique of Detached Woven EndoBridge device: Illustrative series

BACKGROUND

The Woven EndoBridge (WEB) device (MicroVention, Tustin, CA, USA) has an excellent safety profile. While major complications such as device malposition and migration are rare, they can have serious consequences if not addressed promptly. Our case series describes the safety and efficacy of Amplatz goose neck microsnare device (Medtronic in Irvine, CA, USA) in endovascular retrieval of a detached WEB device.

METHODS

We retrospectively reviewed six consecutive patients who underwent endovascular WEB retrieval using Amplatz microsnare device between March 2012 and December 2022.

RESULTS

All six WEB devices were successfully retrieved either directly from the aneurysm sac due to device malpositioning or from a distal branch following device migration. None of the patients experienced intra-operative aneurysm perforation, arterial dissection, or vasospasm attributable to the process of WEB extraction. Five out of six patients (83.3%) had a good functional outcome (mRS 0-1) upon discharge from the hospital and at 24 months.

CONCLUSION

Our experience suggests that detached WEB devices can be safely retrieved using an Amplatz microsnare. Apart from addressing device migration, direct removal of an undersized or malpositioned WEB from the aneurysm sac appears to be a safe option that can be considered when all other rescue techniques have been exhausted.

Successful WEBectomy during embolization of temporal arteriovenous malformation-associated flow-related basilar aneurysms

OBJECTIVE

Intra-procedural WEB device migration is a scarcely reported complication that necessitates prompt intervention.

CASE PRESENTATION

Endovascular treatment of two broad necked flow-related aneurysms was planned aided by WEB-SL (Woven EndoBridge-single layer) devices in a 71-year-old female with known left temporal arteriovenous malformation. Inadvertent distal migration occurred while performing a control angiogram with an automated iodine injector. Immediate retrieval was successfully performed using a Solitaire stent-retriever.

CONCLUSION

To our knowledge, we report for the first time the successful retrieval of a distally migrated WEB using a stent-retriever device.

Simulation of intra-saccular devices for pre-operative device size selection: Method and validation for sizing and porosity simulation

Intra-saccular devices (ID) are novel braided devices used for complex intracranial aneurysms treatment. Treatment success is associated with correct device size selection. A technique that predicts the ID size within the aneurysm before intervention will provide a powerful computational tool to aid the interventionist during device selection. We present a method to calculate the device's final height, radial expansion and porosity within the patient's anatomy, which allows assessing different device sizes before treatment takes place. The proposed sizing technique was tested in-vitro and in real patient's geometries obtained from 3DRA angiographic images of 8 unruptured aneurysms previously treated with IDs. The obtained simulated height was compared to the real height, with a mean error of less than 0.28 mm (±0.44). The porosity calculation method was tested in-vitro with an error of 0.02 (±0.022). The results of both sizing and porosity experiments resemble well measures from real patients. This methodology could be used before treatment to provide the interventionist with additional information that allows selecting the device that best fits the patient's aneurysm to be treated.

Retrieval of Displaced Woven EndoBridge Intrasaccular Flow Disruptor Using Solitaire Platinum Revascularization Device

The Woven EndoBridge (WEB; MicroVention, Aliso Viejo, CA, USA) intrasaccular flow disruptor is a therapeutic option for wide neck bifurcation intracranial aneurysms that does not require the use of adjunctive techniques such as stents or balloon remodeling. As with other endovascular devices, displacement of the WEB is a recognized complication. Few reports have been published regarding the management of this type of complication. We describe a case of retrieval of a displaced WEB using a Solitaire Platinum revascularization device (Medtronic, Minneapolis, MN, USA). Interventionists should be aware of this option in the management of such a complication.

Adjustment of Malpositioned Woven EndoBridge Device Using Gooseneck Snare: Complication Management Technique

The Woven EndoBridge (WEB) is an intrasaccular flow-disrupting device for the treatment of wide-necked saccular cerebral aneurysms. As with any neuroendovascular device, complications in the form of malpositioning and migration must be managed quickly and safely. Few studies have reported complication management techniques in instances of dislocated or migrated WEB devices. We retrospectively describe a case of a malpositioned WEB device that was successfully adjusted with the use of a gooseneck snare. Multiple other intra-procedural bailout strategies for management of WEB malposition and migration were considered, and are herein discussed. Operators should be aware of the causes of WEB malposition and a variety of bailout strategies.

Volume-based sizing of the Woven EndoBridge (WEB) device: A preliminary assessment of a novel method for device size selection

INTRODUCTION

Accurate sizing of the Woven EndoBridge (WEB) device is of critical importance as it determines procedural safety and successful occlusion of wide neck bifurcation aneurysms. The aim of this study was to assess the ability of aneurysm volume to assist in accurate WEB size selection.

METHODS

All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and October 2019 were identified for this retrospective study. Aneurysm volumes were calculated with auto-segmentation using a three-dimensional volume rendering program on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width. Follow-up angiographic outcomes were collected at 6-9 months post-procedure.

RESULTS

Twenty-nine aneurysms were evaluated by 3D rotational angiography. The correlation coefficient with WEB size was larger for auto-segmented aneurysm volumes (r = 0.979) compared to height × width measurements (r = 0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p = 0.0007). Follow-up angiography available in 13 subjects demonstrated an 85% complete aneurysm occlusion rate.

CONCLUSION

Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that volumetric measurements of aneurysm size provide a useful adjuvant measure to assist in appropriate size selection of the WEB device.

Snare salvage technique for deformed WEB device after deployment

The Woven EndoBridge (WEB) device is a new endovascular technology that allows safe and effective treatment of wide-neck bifurcation aneurysms without the need for dual antiplatelet therapy.1-4 The case is presented of a patient in their 50 s with a history of systemic lupus erythematosus and receiving warfarin for recurrent deep venous thrombosis and an unruptured right middle cerebral artery bifurcation aneurysm. The aneurysm was treated with a WEB SL aneurysm embolization device (MicroVention, Tustin, California, USA). After the final deployment, a technical error (inadvertent forward movement of the pusher) led to the deformation of the device along its longitudinal axis, leaving the aneurysm partially untreated. An Amplatz Goose Neck Microsnare was used to capture the proximal detachment marker and used gentle traction to restore the original shape of the device (video 1).5-7 A follow-up angiogram revealed a restoration of the device's shape with a similar result during the 4- month follow-up angiogram. neurintsurg;13/3/294/V1F1V1Video 1.

Woven EndoBridge Device immediate post-detachment tilt with later displacement: Case report, rescue techniques, and review of the literature

The Woven EndoBridge Device (WEB) is efficient and safe in the treatment of wide-neck bifurcation intracranial aneurysms. A crucial step in operative planning is establishing the appropriate dimension of the device, and there are limitations to the therapeutic solutions provided by WEBs. We describe a case of a right middle cerebral artery bifurcation wide-neck aneurysm treated with WEB. After the initial deployment of a WEB proven oversized, we substituted it with a smaller one that presented immediate post-detachment intra-aneurysmal tilt probably resulting from undersizing. The 24-h angiographic control identified a partial displacement of the device in the superior middle cerebral artery branch. We describe rescue techniques with review of the literature and our treatment strategy, including effort to reposition the device followed by stent deployment. The treatment was electively completed by the coil-through technique. The post-detachment WEB tilt should be considered an unstable position and treated either by removal of the device or with adjunctive implants. Each WEB size adapts to a range of aneurysmal height and width. This range is not always the same for each specific WEB dimension, based on the table provided by the manufacturer. This eventually predisposes to a different behavior of different WEB sizes regarding the modification of the device's height in relation to the modification of the diameter after deployment.

Rescue of migrated Woven Endobridge devices using a stent-retriever-technique in a porcine model

PURPOSE

The Woven Endobridge device (WEB) has become widely applied for the treatment of intracranial aneurysms. Complications are rare, however, especially dislocations and migrations can potentially increase poor clinical outcome. The aim of this study was to assess the feasibility and effectiveness of rescuing migrated Woven Endobridges using different stent retrievers.

METHODS

In a porcine model, Woven Endobridges of different sizes (SLS 4, SLS 7, SL 5 × 3, SL 4 × 3) were placed into the axillary arteries. By means of two different stent retrievers (Solitaire Platinum and 3D Revascularization Device), a total of 20 rescue maneuvers were performed. For this purpose, the retrievers were deployed distally of the migrated Woven Endobridges. After retracting the stent retrievers partially, the Woven Endobridges were trapped within the microcatheter. Rescue rates, time, attempts and complications were assessed.

RESULTS

Successful rescue of the migrated Woven Endobridges was observed in all cases (100%). Rescue was slightly faster (177.8 ± 72.8 s vs. 223.4 ± 104.1 s) with fewer attempts (1.5 ± 0.8 vs. 1.8 ± 0.9) when using the 3D Revascularization Device compared to the Solitaire Platinum. However, there were no significant differences (p = 0.327; p = 0.554). Migration of the Woven Endobridges during rescue was seen with both stent retrievers in a comparable frequency (p = 0.642). Further complications, such as entrapment of the stent-retriever-WovenEndobridge-complex at the intermediate catheter, vasospasm, perforation or dissection, were not observed.

CONCLUSIONS

Rescue of migrated Woven Endobridges using stent retrievers is a feasible and effective method. Rescue rates, times and attempts with the Solitaire Platinum and 3D Revascularization Device are comparable with each other.

Different Rescue Approaches of Migrated Woven Endobridge (WEB) Devices: an Animal Study

Purpose

Treatment of wide-necked intracranial aneurysms using the Woven Endobridge (WEB) device has become broadly accepted. Feared complications with the potential of increased poor clinical outcome include dislocations and migration of the device. This study was carried out to determine the effectiveness of a variety of different strategies to rescue migrated WEB devices.

Methods

In a porcine model, WEB devices of different sizes (SL [single layer] 3.5 × 2mm and SL 4.0 × 3 mm, SL 8 × 5 mm and SLS 8 mm [single layer spherical]) were placed into both the subclavian and axillary arteries. A total of 32 rescue maneuvers (8 per rescue device) were performed. Small WEBs were rescued using reperfusion catheters (RC) (SOFIA Plus and JET 7), larger WEBs were rescued using dedicated rescue devices (Microsnare and Alligator). Rescue rates, times, attempts and complications were assessed.

Results

Rescue attempts of migrated WEBs were successful in all cases (100%). Rescue time (p = 0.421) and attempts (p = 0.619) of small WEBs using RCs were comparable without significant differences. Aspiration alone was not successful for larger WEBs. Rescue of larger WEBs was slightly faster (122.75 ± 41.15 s vs. 137.50 ± 54.46 s) with fewer attempts (1 vs. 1.37) when using the Microsnare compared to the Alligator device. Complications such as entrapment of the WEB in the RCs, vasospasm, perforation, or dissection were not observed.

Conclusion

Rescue of migrated WEB devices is a feasible and effective method and 100% successful rescue rates and appropriate rescue times can be achieved for small WEBs using RCs and for larger WEBs using dedicated rescue devices (Microsnare and Alligator).

Rescue Maneuver for Dislocated Woven EndoBridge Device in Middle Cerebral Artery

BACKGROUND

Intrasaccular flow disruption has emerged as a useful modality for treatment of wide-necked saccular aneurysm at vessel bifurcations. The Woven EndoBridge (WEB) device is one such device that has been evaluated in several series with excellent safety and good midterm efficacy. Bailout techniques to retrieve or reposition a dislocated WEB device are sparse and associated with significant risks. We describe a case of a dislocated WEB device that was repositioned with a microcatheter alone.

METHODS

We describe a case of a WEB device that inadvertently detached in the parent vessel and the technique we used to reposition it. A number of bailout techniques are discussed with pros and cons associated with each maneuver.

RESULTS

An unruptured middle cerebral artery (MCA) aneurysm was treated by endovascular embolization with a WEB device. The WEB was deployed within the aneurysm without incident. However, the device failed to detach. While attempting to resheath the device, it extruded out of the aneurysm and then inadvertently detached in the MCA. After many options were considered, a microcatheter alone was used to push the device back into the aneurysm.

CONCLUSION

Caution should be exercised, especially when detaching the WEB device. Microcatheter repositioning by pushing the dislocated device may be attempted, especially if part of the device is within the aneurysm. This is the first description of the described microcatheter repositioning rescue maneuver.