Basilar Artery Bifurcation Aneurysm: Ruptured Wide-Necked Basilar Bifurcation Aneurysm Presenting with Atypical Clinical Signs and Symptoms, Treated with a WEB Device After a Failed Attempt at Coil Occlusion

  • Maxim BesterEmail author
  • Jens Fiehler
  • Jan-Hendrik Buhk
Living reference work entry


A 40-year-old male patient was referred to our emergency room with non-specific symptoms such as becoming progressively more agitated and a change in personality. While taking his medical history with his wife, she described a sudden onset of symptoms during sexual intercourse which then worsened. A scheduled CT scan revealed a basal subarachnoid hemorrhage graded at Hunt and Hess II, Fisher IV, due to a ruptured wide-neck basilar bifurcation aneurysm. After an initial unsuccessful treatment attempt using just a coil to occlude the aneurysm, the patient was successfully treated with a WEB device. The treatment of basilar artery bifurcation aneurysms with efferent arteries incorporation using a Woven EndoBridge (WEB) is the main topic of this chapter.


Basilar artery bifurcation Wide-necked bifurcation aneurysm Coil occlusion failed attempt Woven EndoBridge WEB 


A 40-year-old male patient, previously healthy, was admitted to our emergency room because of progressive agitation, a change in personality, and a headache, which he described as moderate at best. Initially, both a toxicological screening and psychiatric examination were scheduled. Once the patient’s wife arrived at the hospital, she reported that the symptoms had started suddenly during sexual intercourse that morning. In the meantime the patient had developed a progressive impairment in consciousness. Further examinations revealed a spontaneous SAH, graded at Hunt and Hess II, Fisher IV.

Diagnostic Imaging

A non-contrast computer tomography (NCCT) scan showed a diffuse basal subarachnoid hemorrhage (SAH) and dilated lateral ventricles. The subsequently performed CT angiography (CTA) revealed a wide-necked, irregularly shaped basilar artery bifurcation aneurysm with a maximum fundus diameter of about 8 mm (Fig. 1). Treatment for acute hydrocephalus, including the insertion of an external ventricular drain (EVD), was immediately initiated.
Fig. 1

CT examination in a 40-year-old man with spontaneous SAH. NCCT shows subarachnoid blood in the basal cisterns and acute hydrocephalus (a, b). CTA reveals a wide-necked aneurysm of the basilar artery bifurcation with an irregular shape and a maximum fundus diameter of about 8 mm (lateral view (c), frontal view (d))

Following this, the patient was immediately transferred to the angiography suite for endovascular aneurysm treatment. DSA confirmed a wide-necked aneurysm (neck width 5.7 mm, fundus depth 8.4 mm, biplane width 6.4 mm and 7.5 mm) of the basilar artery bifurcation with a broad involvement of the origins of both P1 segments, especially the left hand P1. The left superior cerebellar artery (SCA) origin was also involved in the neck region of the aneurysm. As well as the aneurysm, a distal basilar artery fenestration was also observed (Fig. 2).
Fig. 2

Diagnostic DSA prior to the endovascular treatment attempt on an aneurysm on the basilar artery bifurcation. Only the right-hand superior cerebellar artery (SCA) is separate from the aneurysm neck. Both PCA origins (particularly the left) as well as the origin of the left SCA are incorporated into the aneurysm neck. Given the large caliber of the left PcomA (a), an occlusion of the left-hand P1 segment might have been tolerated, while the concurrent occlusion of the left SCA would most likely have caused a pontocerebellar infarct. The 3D reconstruction of a rotational DSA (b) confirms the incorporation of both PCA origins into the neck region of the aneurysm. As an additional finding, a fenestration of the basilar artery was also observed

Treatment Strategy

The goal of the treatment was to occlude the aneurysm in order to prevent a re-rupture. Therefore, it was decided to perform immediate endovascular treatment (EVT). As due to weekend staffing levels, the attending neuroradiology consultant decided to attempt treatment by coil occlusion.


Procedure #1, 19.11.2015: endovascular treatment attempt on a wide-necked basilar artery bifurcation aneurysm by coil occlusion

Anesthesia: general anesthesia; 3000 IU unfractionated heparin (Heparin-Natrium, B. Braun) IV, 250 mg ASA (Aspirin i.v., Bayer Vital) given IV after the first coil had been deployed

Premedication: none

Access: right femoral artery; 6F 10 cm sheath (Terumo); guide catheter: 6F Vista brite tip (Cordis); microcatheter: Excelsior SL10 (Stryker); microguidewire: Traxcess 0.014″ 200 cm (MicroVention)

Implant: HydroFrame 18 6/19 (MicroVention), inserted into the aneurysm and then withdrawn

Course of treatment: The right VA was catheterized with a 6F guide catheter. The microcatheter was then advanced into the aneurysmal sac over a 0.014″ microguidewire. A 6 mm diameter framing coil was deployed in the aneurysm sac. Because the aneurysm base was inadequately defined toward the left P1 segment, the coil was repositioned twice without a satisfactory outcome. As it was felt that the coil treatment would not have a satisfactory outcome and that WEB treatment would be possible the following day, the intervention was halted and postponed until the next morning (Fig. 3).
Fig. 3

Treatment attempt on a wide-necked basilar bifurcation aneurysm using a framing 3D coil (HydroFrame 18 6/19). Three different coil positions show inadequate coverage of the aneurysm neck (a, b, c). An inadvertent occlusion of the PCA origins and an unstable position of the coil were anticipated which prompted the decision to withdraw the coil

Duration: 1st–23rd DSA run: 55 min; fluoroscopy time: 17.5 min

Complications: none

Postmedication: none

Procedure #2, 20.11.2015: endovascular treatment of a ruptured wide-necked aneurysm of the basilar artery bifurcation using a WEB

Anesthesia: general anesthesia; 3000 IU unfractionated heparin (Heparin-Natrium, B. Braun) IV; 250 mg ASA (Aspirin i.v., Bayer Vital) IV after the WEB detachment

Premedication: 250 mg ASA (Aspirin i.v., Bayer Vital) IV, given the previous day

Access: right femoral artery, 6F 10 cm sheath (Terumo); guide catheter: 6F Vista brite tip; microcatheter: VIA 27 (MicroVention); microguidewire: Traxcess 0.014″ 200 cm (MicroVention)

Implant: WEB SL 7/3 (MicroVention)

Course of treatment: The right VA was catheterized with a 6F guide catheter. A VIA27 microcatheter was then advanced into the aneurysmal sac over a 0.014″ microguidewire. The WEB size was calculated with reference to the larger basal aspect of the aneurysm with the intention to “cork” the aneurysm neck without completely blocking the aneurysm fundus with the WEB device (Fig. 4). Therefore, an implant with a relatively undersized height (SL 7/3) was chosen. The WEB was deployed in the proximal aneurysm compartment by microcatheter retraction. After the initial deployment, a DSA run revealed a lateral basal inflow into the aneurysm while the aneurysm neck was not fully obliterated by the WEB. After repositioning the implant by increasing the tension of the wire a little, an improved defined basal recess was shaped by applying gentle pressure to the wire. The DSA run showed a correct basal apposition of the WEB and the delayed washout of the contrast agent from the aneurysm dome. The WEB was detached under fluoroscopic control without being repositioned further. At the end of the procedure, DSA confirmed that the distal compartment of the aneurysm had been completely occluded, with contrast medium stagnation inside the WEB (Figs. 5 and 6).
Fig. 4

Perpendicular angulation of the 3DRA for WEB sizing (a, b)

Fig. 5

Initial WEB position (a, b) with the aneurysm fundus filling from the aneurysm neck beside the WEB (arrow, (b)). Despite delayed washout of contrast medium from the aneurysm fundus (arrow, (c)) the WEB device was subsequently repositioned

Fig. 6

Proximal repositioning of the WEB device with formation of the basal recess (arrow, (a)) and a complete adaptation of the WEB to the aneurysm wall (arrow, (b)). Shortly after detaching the WEB, the aneurysm fundus was no longer being filled (arrow, (c)), while the origins of both PCAs remained patent

Duration: 1st–9rd DSA run: 30 min; fluoroscopy time: 9 min

Complications: none

Postmedication: none

Clinical Outcome

The patient was extubated the following day and had no new neurological or functional deficit. The external ventricular drain was removed after 10 days. The patient was discharged to an outpatient rehabilitation unit 1 week later with no neurological deficit (mRS 0).

Follow-Up Examinations

A routine MRI scan 2 weeks after the intervention showed a complete occlusion of the aneurysm with no signs of hydrocephalus (Fig. 7). DSA follow-up is pending.
Fig. 7

T2WI MRI prior discharge shows no sign of hydrocephalus (a). ToF-MRA confirms complete obliteration of the aneurysm (arrow (b)), and T1 black-blood imaging reveals early thrombus formation in the aneurysm fundus (arrow, (c))


Treating wide-necked aneurysms is sometimes challenging for the interventionist when using elaborate remodeling techniques such as balloon- or stent-assisted coiling. As an added complication, as an SAH deriving from a ruptured aneurysm requires immediate treatment, it is not possible to carry out either an extensive antiplatelet regime or comprehensive testing beforehand. Although stent-assisted coiling (in our case Y-stenting or similar) or using an intraluminal device to cover the neck (e.g., pCONus, phenox) would have been feasible in this case, these require a substantial antiaggregation regimen (including Gp IIb/IIIa antagonists), which could potentially complicate further therapy such as ventricular drainage. In contrast, the WEB device (Woven Endobridge, MicroVention) is a sheer intrasaccular flow disruptor, which modifies the blood flow at the level of the aneurysm neck and induces aneurysmal thrombosis. The nitinol braided device is self-expanding, retrievable, and thermally detachable. As there is no potential thrombogenic material in the parent vessel, antithrombotic agents are not routinely required. The optimum size of the implant is determined using vertical 3DRA images. Several iterations of the WEB device have been developed over the last years. The latest update introduced smaller devices (down to 3/2 mm) and low-profile devices that are compatible with a 0.017″ ID microcatheter (for a WEB device up to 7 mm wide). To date, several studies have suggested that the WEB device is both safe and effective in treating incidental (Pierot et al. 2016) and ruptured (Liebig et al. 2015) wide-necked aneurysms. Interim adequate aneurysm occlusion rates have been reported at around 85% with perioperative morbidity rates of around 2% (Asnafi et al. 2016). Follow-up imaging after WEB implantation should be done by DSA since MRI/MRA examinations can be misleading (Nawka et al. 2018).



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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Klinik und Poliklinik für Neuroradiologische Diagnostik und InterventionUniversitätsklinikum Hamburg-EppendorfHamburgGermany

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