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Original research
Balloon remodeling-assisted Woven EndoBridge technique: description and feasibility for complex bifurcation aneurysms
  1. Cristian Mihalea1,2,
  2. Simon Escalard3,
  3. Jildaz Caroff1,
  4. Léon Ikka1,
  5. Aymeric Rouchaud4,
  6. Valerio Da Ros1,5,
  7. Igor Pagiola1,6,
  8. Joaquin Jose Marenco de la Torre1,
  9. Thomas Yasuda1,
  10. Bogdan Valeriu Popa7,8,
  11. Horia Ples2,
  12. Nidhal Benachour1,
  13. Augustin Ozanne1,
  14. Jacques Moret1,
  15. Laurent Spelle1
  1. 1 Department of Interventional Neuroradiology, Neuro Brain Vascular Center, Hopital Bicetre, APHP, Paris Sud Université, Paris, France
  2. 2 Department of Neurosurgery, University of Medicine and Pharmacy “Victor Babes”, Timisoara, Romania
  3. 3 Department of Interventional Neuroradiology, Fondation Rothschild Hospital, Paris, France
  4. 4 Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
  5. 5 Department of Diagnostic Imaging and Interventional Radiology, University Hospital of Rome "Tor Vergata", Rome, Italy
  6. 6 Department of Interventional Neuroradiology, Universidade Federal de São Paulo, São Paulo, France
  7. 7 Department of Radiology and Medical Imaging, “Floreasca” Clinical Emergency Hospital, Bucharest, Romania
  8. 8 “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
  1. Correspondence to Dr Cristian Mihalea, Department of Interventional Neuroradiology, Neuro Brain Vascular Center, Hopital Bicetre, APHP, Paris Sud Université, Paris 92110, France; cristianmihalea{at}


Background Woven EndoBridge (WEB) deployment remains challenging in aneurysms with a complex shape or orientation.

Objective To show that embolization of wide-neck bifurcation aneurysms using the WEB device balloon remodeling-assisted technique is a feasible and elegant endovascular solution compared with other techniques, such as balloon remodeling or stent-assisted coiling.

Materials and methods 10 cases (10 aneurysms in 9 patients) of balloon remodeling-assisted WEB treatment of unruptured complex bifurcation aneurysms were treated in our institution and retrospectively analyzed. Details of clinical presentations, technical details, perioperative and postoperative complications, and outcomes were collected. Immediate and long-term angiographic results were also evaluated.

Results Aneurysms included six middle cerebral artery aneurysms, one anterior communicating artery aneurysm, one posterior communicating artery aneurysm, one basilar artery aneurysm, and one T-shaped carotid aneurysm. Mean dome width was 6.55 mm, mean neck size 4.5 mm, mean height 4.79 mm, and mean dome-to-neck ratio was 1:1.46. Treatment was performed exclusively with the balloon remodeling-assisted WEB technique in all cases. The device was successfully deployed in every case. Periprocedural thromboembolic or hemorrhagic events did not occur. The modified Rankin Scale score at discharge was 0 for all patients. At mid-term or long-term angiographic follow-up, adequate occlusion was observed in 7 aneurysms from 8 controlled cases (87.5%), and one patient (2 aneurysms) did not have angiographic follow-up.

Conclusion The balloon remodeling-assisted WEB technique seems to be a safe and effective solution for endovascular treatment of unruptured wide-neck bifurcation aneurysms with specific complex anatomy. However, further studies are needed to evaluate the rate of complications and long-term efficacy.

  • aneurysm
  • balloon
  • intervention
  • technique
  • stent

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Endovascular treatment is now the first-line treatment for ruptured and unruptured aneurysms since the International Subarachnoid Aneurysm Trial (ISAT)1 and CLARITY2 studies. Aneurysms with a complex anatomy (specifically, wide-neck aneurysms) are in some cases untreatable or difficult to treat with standard coiling, balloon-assisted coiling, stent-assisted coiling, and flow diversion.3–5 The safety and efficacy of the Woven EndoBridge (WEB) device has now been well described, and its use for the treatment of wide-neck aneurysms has shown promising rates of adequate occlusion with low rates of morbidity and mortality.6 7

The device has been progressively developed since 2010 from a dual-layer version (WEB DL) to single-layer versions (WEB SL and WEB SLS (single layer spherical)). Good clinical practice trials showed good safety and efficacy of the treatment, with no mortality and 2.7% morbidity at 1 month after treatment.8–10 In a recent meta-analysis, perioperative morbidity and mortality rates were 4% and 1%, respectively.11

However, the treatment of unruptured complex bifurcation aneurysms remains challenging,11 owing to irregular shapes or orientation of the aneurysm on parent vessels or the bifurcation layout itself. Endovascular treatment of this particular type of aneurysm often requires device-assisted procedures, such as balloon or stent assistance.12 The aim of this study is to report the safety and feasibility of the balloon remodeling-assisted WEB technique in the treatment of 10 unruptured complex bifurcation aneurysms. In all cases, balloon remodeling was used to fine-tune the positioning of the WEB device before detachment in such a way that the central line between the two radiopaque markers of the device was parallel with the perpendicular axis of the aneurysmal neck.

Materials and methods


Between November 2015 and April 2018, nine patients (seven women, two men; age range 43–66 years (mean 55.7 years)), with 10 non-ruptured intracranial aneurysms were retrospectively enrolled for this study, which was performed according to the guidelines of our institution. After a multidisciplinary discussion, treatment with the WEB device was decided depending on the aneurysm characteristics (size, wide-neck, bifurcation location, etc), taking into account high risks of failure or recanalization with a standard coiling technique. The study was designated as a retrospective analysis, and therefore no ethics committee review was required.

Treatment technique

Endovascular treatment was performed under similar conditions as for standard coiling for unruptured aneurysms using a biplane flat-panel angiographic system (Allura Xper 20/10; Philips, Best, Netherlands). No double antiplatelet therapy was systematically given before or during the endovascular treatment. Under general anesthesia and also systemic heparinization, a single femoral puncture allowed the positioning of a long delivery catheter (Neuron Max 088, Penumbra, Alameda, California, USA) at the origin of the internal carotid artery or vertebral artery. Then the 6F guiding catheter (FargoMax, Balt, Montmorency, France or Navien, Covidien, Irvine, California, USA) was advanced into the intracranial internal carotid artery. The microcatheter (Via 27, Via 21, or Via 17) was positioned inside the aneurysm. The operator decided which device type and size to use according to the aneurysm measurements, and then the WEB was positioned and delivered inside the aneurysmal sac. VasoCT was performed immediately to determine the relation between bifurcation and the WEB device before a decision to detach was made.

In these 10 cases, after first deploying the device, the operator found that the initial positioning of the WEB was not satisfactory (mainly due to protrusion into the bifurcation). Thus, the device was resheathed and repositioned by the balloon remodeling-assisted WEB technique at the same time as deployment. Two types of balloon were used: HyperGlide 4*10 mm (Medtronic Neurovascular, Irvine, California, USA) and Scepter C 4*10 mm (MicroVention, Tustin, California, USA), and the second deployment of the device was done with balloon inflation in one of the bifurcation branches. In all cases, the same WEB device was used initially without, and then with, the balloon remodeling-assisted technique.

WEB sizing

Correct sizing of the device is very important and is challenging for the operator. Sizing was not done under a specific rule but done as previously described by Caroff et al 13: oversizing the WEB width by 1 mm and downsizing the WEB height by 1 mm to avoid protrusion and aneurysm wall apposition at the same time.

Control imaging

Control digital subtraction angiography (DSA) and VasoCT were performed after each delivery of the device. At the end of the procedure, DSA and a third VasoCT was carried out after detachment of the WEB.

If no thrombotic complications were observed, antiplatelet therapy was stopped.


The repositioning and differences between the two deployments (without and with balloon) were evaluated by two neuroradiologists (JM and LS) on the basis of both DSA and VasoCT data (figures 1, 2, and 3). The quality of the occlusion was evaluated at mid-term and long-term follow-up by angiographic examination (table 1).

Aneurysm location and size, implanted device, balloon used, and anatomical results at the follow-up DSA were recorded (table 1).

Figure 1

(A, B and C) Initial angiography: three-dimensional (3D) rotational angiography and 2D anteroposterior images showing a middle cerebral artery aneurysm. (D, E and F) First attempt to deploy the Woven EndoBridge (WEB) device in the aneurysm, showing a protrusion of the device into the upper branch (red arrow). (G) Second attempt to reposition the WEB device at the aneurysm sac, with balloon (Scepter C 4*11 mm) inflated at the point of the bifurcation. (H) Final control angiogram and VasoCT without protrusion of the device at the bifurcation level (red arrow). (I) Fifteen-month follow-up angiography showing total occlusion of the aneurysm.

Figure 2

(A) Three-dimensional angiogram of the right middle cerebral artery (MCA) aneurysm. (B) Microcatheterization of the aneurysm sac with microcatheter Via 21. (C) Unsubtracted image showing the Woven EndoBridge (WEB) device inside the aneurysm. (D and E) Control angiogram and VasoCT showing a notable neck remnant. (F and G) Second attempt to deploy the same WEB device with the assistance of a balloon inflated in the inferior branch of the right ACM bifurcation in order to tilt the WEB device at the neck level of the aneurysm. (H) Final VasoCT showing a better position of the device covering the neck completely. (I) Six-month follow-up angiogram showing total occlusion of the aneurysm.

Figure 3

(A and B) Anterior communicating artery (ACA) bilobed aneurysm: 3D image and work projection, respectively; (C, D, E, F, and G) Two-dimensional work projection—HyperGlide 4*10 mm balloon at the left ACA A1–A2 segments to tilt the Woven EndoBridge device and adjust it at the neck level, avoiding protrusion into the bifurcation and also fitting the device in the main aneurysmal sac. (H) Final VasoCT image showing the device completely covering the neck and patency of the bifurcation. (I) Fifteen-month follow-up angiogram showing total occlusion.

Table 1

Aneurysm location and size, implanted device, balloon used and anatomical results at the follow-up DSA



Six MCA aneurysms, one anterior communicating artery aneurysm, one posterior communicating artery aneurysm, one basilar artery aneurysm, and one T-shaped carotid aneurysm were treated in our institution and retrospectively analyzed. The mean dome width was 6.55 mm, mean neck size 4.5 mm, mean height 4.79 mm and mean dome-to-neck ratio was 1:1.46. All treatments involved the balloon remodeling-assisted WEB technique.

Between November 2015 and April 2018, a total of 68 WEB treatments were performed in our institution from which 10 aneurysms (14.7%) benefited from the technique described in this paper.


The WEB device was successfully deployed in every case on the second attempt, in combination with balloon remodeling assistance.

In all cases two senior operators (JM and LS) retrospectively reviewed the intermediate and final VasoCT scans and also the intermediate runs (without balloon) and final runs after balloon-assisted deployment of the device in a subtracted and non-subtracted way. They concluded that in all cases the position of the device was significantly changed, with ranges between 5 and 15 degrees.

No periprocedural rupture, and no hemorrhagic or thrombotic complications occurred. Final angiograms showed no residual clotting or branch occlusion, and no clinical consequences were seen. No clinically relevant hemorrhagic complication occurred during hospitalization of any of the nine patients. On discharge, all patients had a modified Rankin Scale score of 0.

Angiographic follow-up

Eight patients received angiographic follow-up, the mean of which was 8.9  months (range 3–18). The DSA had not been performed on one patient by the time this work was submitted.

Total aneurysm occlusion was achieved in six patients; in one patient a small neck remnant caused by compaction of the device was detected and an aneurysm remnant was found in the remaining case. However, in this particular case the follow-up DSA was done only 5 months after treatment.

Thus, adequate occlusion (complete occlusion in six aneurysms and one small neck remnant) was achieved in seven of our eight controlled patients (85.7%). No modification of the clinical status or bleeding occurred between discharge and follow-up in any patient.


These cases illustrate the utility of the balloon remodeling-assisted WEB technique, which is already in use for treatment of complex aneurysms. In all the cases, the balloon was used to tilt and shift the WEB device before detachment in such a way that no protrusion or neck remnant occurred.

Now that smaller Via microcatheters are more frequently used (a downsize from 0.021 inches to 0.017 inches), the feasibility of the balloon remodeling-assisted WEB technique has increased, and more bifurcation aneurysms are suitable for this technique—especially those of small size. This technique has been particularly useful in cases where there is angulation between the bifurcation and the aneurysm.

Particularly in situations with angulation between the bifurcation plane and aneurysm plane itself, this technique proved to be useful. The WEB device central axis (between the two radiopaque markers) can be adjusted, with the aneurysm plane represented by the orthogonal plane at the neck level, avoiding branch protrusion. To achieve this, the balloon was placed in the branch of the protrusion and inflated before the full deployment of the WEB. The decision to attempt a balloon remodeling-assisted WEB technique was made only after deployment of the device without any other adjuvant techniques and analysis of the 2D and VasoCT images. In most cases, the operator concluded that the device protrusion could be corrected by inflation of a compliant balloon at the bifurcation level, and a second, improved deployment of the same device was performed (figure 1).

The second situation in which this technique was used included cases in which the operator found a neck remnant after first deployment of the WEB device. This was remedied by using deployment under balloon inflation (figure 2). To achieve this, the balloon was placed in the parent branch opposite to the orientation required and inflated before full deployment of the WEB device.

The third situation in which this technique was useful was complex bifurcation bilobed aneurysms (figure 3). In this case the balloon was used to tilt the WEB, attempting to position the device in the bigger aneurysmal sac and at the same time to cover the neck. Although the procedures were carried out successfully, we are aware of the limitations of the study due to its retrospective nature and the very small number of patients.

The balloon remodeling-assisted WEB technique was chosen to treat the aneurysms because of the complexity of other possible treatments, such as stent-assisted coiling, Y-stenting, or the flow-diverter technique, and was performed by highly trained operators who were experienced with WEB devices. This study has illustrated how the balloon remodeling-assisted WEB technique permits deployment of the WEB device to be modified, allowing better control of the procedure, for which other treatments are considered technically challenging. To our knowledge, this is the first study of unruptured aneurysms treated with the balloon remodeling-assisted WEB technique and represents an important initial experience.


From this preliminary retrospective study, the balloon remodeling-assisted WEB technique seems to be a safe and effective solution for endovascular treatment of unruptured wide-neck bifurcation aneurysms with complex anatomy.

However, further studies are needed to evaluate the complication rate and long-term efficacy.



  • Contributors All authors have contributed equally to this work. Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work was done by CM, SE, JC, LI, AR, VDR, and IP. Drafting the work or revising it critically for important intellectual content was finalized by TY, JJMdlT, BVP, and HP. Final approval of the version to be published was given by NB , AO, JM, and LS. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: CM, JC, IP.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval AP-HP ethical committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.