Woven EndoBridge (WEB)

Woven EndoBridge (WEB)

The Woven EndoBridge (WEB) (Sequent Medical, Aliso Viejo, California), is a ellipsoid braided-wire embolization device designed to provide flow disruption along the aneurysm neck 1).

Placed in the aneurysm, the device will modify the blood flow at the level of the neck and induce aneurysmal thrombosis. The WEB shape was designed to treat wide necked aneurysm. The device has been developed progressively from a dual-layer version (WEB DL) to single-layer versions (WEB SL and WEB SLS [single-layer spherical]).

This device does not require long-term antiplatelet use.


For the treatment of both ruptured and unruptured aneurysms. The WEB has received the CE mark and to date has been used to treat a wide variety of more than 1,400 aneurysms in Europe, Latin America and New Zealand. The WEB is not available for sale or use in the United States.

The WEB is a self-expanding, oblate, braided nitinol mesh.

The device is composed of an inner and outer braid held together by proximal, middle, and distal radiopaque markers, creating 2 compartments: 1 distal and 1 proximal. Depending on the device diame- ter, the inner and outer braids are 108 wires or 144 wires. Therefore, blood flow into a WEB-embolized aneurysm initially encounters 2 layers of wires comprising 216 or 288 wires, with the largest interwire distance ranging from 106 to 181 􏰅m, respectively, depending on the device size. The WEB implant is deployed—or retrieved before de- tachment—in a manner similar to that in endovascular coil systems, through microcatheters with an internal diameter 􏰆0.027 inch. For devices with a diameter of 􏰇7 mm, microcatheters with an internal diameter of 0.027 inch are used; and for devices with a diameter 􏰁7 mm, microcatheters with an internal diameter 0.032 inch are used. The detachment system is electrothermal and instantaneous. 2).

In a study, there was no difference in the early clinical course between those treated with WEB embolization, coil embolization, or neurosurgical clipping. Since WEB embolization is a valuable treatment alternative to coiling, it seems not justified to exclude this procedure from upcoming clinical SAH trials, yet the clinical long-term outcome, aneurysm occlusion, and retreatment rates have to be analyzed in further studies 3).


The WEB Clinical Assessment of Intrasaccular Aneurysm Therapy (WEBCAST) trial is a prospective European trial evaluating the safety and efficacy of WEB in wide necked aneurysm of the bifurcation.



It does not immediately secure the aneurysm in most subarachnoid hemorrhage cases. Second, it may not be suitable for embolization of wide-neck aneurysms with an unfavorable aspect ratio. To overcome these limitations, Zanaty et al., used the WEB device in conjunction with stenting and/or coiling.

They presented a technical note with an illustrated case-series, and provide a detailed step-by-step description on how the WEB device can be used in adjunct to coiling and/or stenting to achieve successful angiographic results. Accurate sizing of the WEB device before deployment is critical. Larger case-series are required to further assess the safety and success of these combined techniques 4).

Systematic review and meta-analysis

Zhang et al. searched the PubMedOvid MEDLINE, and EMBASE databases between December 1, 2012 and June 30, 2018.

Studies that included five or more patients undergoing WEB for Wide necked intracranial aneurysms, reported an angiographic or clinical outcomeand risk factors, and were published after December 1, 2012 were eligible.

Major outcomes included initial or short-term complete and adequate occlusion. Secondary outcomes included treatment failure, recanalizationmortalitymorbidity, and complication (e.g., thromboembolism or intraoperative rupture) rates. A random-effect model was used to pool the data. To assess risk factors for short-term angiographic outcomes and the most common complications, they conducted subgroup analyses and obtained odds ratios with 95% confidence intervals.

They included 36 studies (1759 patients with 1749 aneurysms). The initial complete and adequate occlusion rates were 35% and 77%, respectively. After a mean follow-up of 9.34 months, the short-term complete and adequate occlusion rates were 53% and 80%, respectively. Thromboembolism and recanalization were the most common complications (both 9%), followed by mortality (7%), morbidity (6%), failure (5%) and intraoperative rupture (3%). The following factors were related to higher short-term obliteration rates: unruptured status, in the anterior circulation, a medium neck (4-9.9 mm), newer-generation WEB and treatment without additional devices. Ruptured status, anterior circulation, preoperative antiplatelet therapy and newer-generation WEB were not significantly related to withto thromboembolism.

WEB has a satisfactory safety profile and shows promising efficacy in treating wide-neck intracranial aneurysms. They preliminarily identified several risk factors for short-term angiographic outcomes 5).

Case series



Ding YH, Lewis DA, Kadirvel R, Dai D, Kallmes DF. The Woven EndoBridge: a new aneurysm occlusion device. AJNR Am J Neuroradiol. 2011 Mar;32(3):607-11. doi: 10.3174/ajnr.A2399. Epub 2011 Feb 17. PubMed PMID: 21330397.

Pierot L, Liebig T, Sychra V, Kadziolka K, Dorn F, Strasilla C, Kabbasch C, Klisch J. Intrasaccular flow-disruption treatment of intracranial aneurysms: preliminary results of a multicenter clinical study. AJNR Am J Neuroradiol. 2012 Aug;33(7):1232-8. doi: 10.3174/ajnr.A3191. Epub 2012 Jun 7. PubMed PMID: 22678844.

Sauvigny T, Nawka MT, Schweingruber N, Mader MM, Regelsberger J, Schmidt NO, Westphal M, Czorlich P. Early clinical course after aneurysmal subarachnoid hemorrhage: comparison of patients treated with Woven EndoBridge, microsurgical clipping, or endovascular coiling. Acta Neurochir (Wien). 2019 Jul 6. doi: 10.1007/s00701-019-03992-4. [Epub ahead of print] PubMed PMID: 31280480.

Zanaty M, Roa JA, Dandapat S, Samaniego EA, Jabbour P, Hasan D. Diverse Use of the WEB Device: A Technical Note on WEB Stenting and WEB Coiling of Complex Aneurysms. World Neurosurg. 2019 Jul 10. pii: S1878-8750(19)31933-3. doi: 10.1016/j.wneu.2019.07.027. [Epub ahead of print] PubMed PMID: 31301439.

Zhang SM, Liu LX, Ren PW, Xie XD, Miao J. Effectiveness, safety and risk factors of Woven EndoBridge device in the treatment of wide-neck intracranial aneurysms : systematic review and meta-analysis. World Neurosurg. 2019 Aug 13. pii: S1878-8750(19)32175-8. doi: 10.1016/j.wneu.2019.08.023. [Epub ahead of print] PubMed PMID: 31419591.

p64 Flow Modulation Device

p64 Flow Modulation Device

(Phenox, Bochum, Germany).


The p64 Flow Modulation Device is a flow diverter. It allows complete deployment and full recoverability. This provides added safety and security.

• Complete deployment and recoverability ensures optimal placement

• Greater neck coverage due to the 64 Nitinol wire braid maximizes hemodynamic flow effect in the aneurysm

• Visualization is achieved by 2 helical strands along entire length of the implant and eight proximal markers

• p64 is mechanically detached once optimally placed

• Implanted via a 0.027“ ID microcatheter

The p64 is a flow modulation device designed to be used in endovascular treatment of intracranial aneurysms. There is limited data on the long-term effectiveness of the device. A study of Sirakov et al. sought to determine the safety and long-term efficacy of this device.

A retrospective review of aprospectively maintained database was performed to identify all patients treated with a p64 between March 2015 and November 2018 at University Hospital St. Ivan Rilski. Anatomical features, intraprocedural complications, clinical, and angiographic outcomes were also taken into account and reviewed.

A total of 72 patients with 72 aneurysms who met the inclusion criteria were identified. Device placement was successful in all patients. Follow-up angiographic imaging at 6 months showed complete occlusion (O’Kelly-Marotta grading scale [OKM] D) in 55 (76.3%) patients, subtotal aneurysmal filling (OKM B) in 10 (13.8%) patients, and neck remnant (OKM C) in 7 (9.7%) patients. Catheter angiography at 12 months was available for 70 patients (97.2%) and of these patients 91.4% of the aneurysms were completely occluded (OKM D) (64/72). Delayed angiography at 24 months was available for 68 patients (94.4%) and of these 98.5% (67/68) had completely occluded aneurysms. A 36-month angiography was available for 61 patients (84.4%) by which point all aneurysms had been completely occluded (100%). Permanent morbidity due to delayed aneurysmal rupture occurred in one patient (1.38%). The mortality rate was 0%. Self-limiting mild intimal hyperplasia was seen in 2 patients (2.72%).

Treatment of intracranial aneurysms with a p64 flow modulation device is safe and effective with a high success rate and only infrequent complication 1).

Girdhar et al., reported the thrombogenic potential of the following flow diversion devices measured experimentally in a novel human blood in-vitro pulsatile flow loop model: Pipeline™ Flex Embolization Device (Pipeline), Pipeline™ Flex Embolization Device with Shield Technology™ (Pipeline Shield), Derivo Embolization Device (Derivo), and P64 Flow Modulation Device (P64). Thrombin generation (Mean ± SD; μg/mL) was measured as: Derivo (28 ± 11), P64 (21 ± 4.5), Pipeline (21 ± 6.2), Pipeline Shield (0.6 ± 0.1) and Negative Control (1.5 ± 1.1). Platelet activation (IU/μL) was measured as: Derivo (4.9 ± 0.7), P64 (5.2 ± 0.7), Pipeline (5.5 ± 0.4), Pipeline Shield (0.3 ± 0.1), and Negative Control (0.9 ± 0.7). They found that Pipeline Shield had significantly lower platelet activation and thrombin generation than the other devices tested (p < .05) and this was comparable to the Negative Control (no device, p > .05). High resolution scanning electron microscopy performed on the intraluminal and cross-sectional surfaces of each device showed the lowest accumulation of platelets and fibrin on Pipeline Shield relative to Derivo, P64, and Pipeline. Derivo and P64 also had higher thrombus accumulation at the flared ends. Pipeline device with Phosphorylcholine surface treatment (Pipeline Shield) could mitigate device material related thromboembolic complications 2).

In preliminary in vivo experiments, antithrombogenic hydrophilic coating (HPC) p64 FDSs appeared to be biocompatible, without acute inflammation 3).

Treatment with p64 is associated with an overall rate of 8.5% moderate in stent stenosis (ISS) (50-75%) and 2.7% severe ISS (>75%), which is comparable with the rate of ISS reported in the literature for other flow diverting stents. There is a tendency for ISS to spontaneously improve over time 4)



Sirakov S, Sirakov A, Bhogal P, Penkov M, Minkin K, Ninov K, Hristov H, Karakostov V, Raychev R. The p64 Flow Diverter-Mid-term and Long-term Results from a Single Center. Clin Neuroradiol. 2019 Aug 9. doi: 10.1007/s00062-019-00823-y. [Epub ahead of print] PubMed PMID: 31399749.

Girdhar G, Ubl S, Jahanbekam R, Thinamany S, Belu A, Wainwright J, Wolf MF. Thrombogenicity assessment of Pipeline, Pipeline Shield, Derivo and P64 flow diverters in an in vitro pulsatile flow human blood loop model. eNeurologicalSci. 2019 Jan 8;14:77-84. doi: 10.1016/j.ensci.2019.01.004. eCollection 2019 Mar. PubMed PMID: 30723811; PubMed Central PMCID: PMC6350389.

Martínez Moreno R, Bhogal P, Lenz-Habijan T, Bannewitz C, Siddiqui A, Lylyk P, Hannes R, Monstadt H, Henkes H. In vivo canine study of three different coatings applied to p64 flow-diverter stents: initial biocompatibility study. Eur Radiol Exp. 2019 Jan 22;3(1):3. doi: 10.1186/s41747-018-0084-z. PubMed PMID: 30671686; PubMed Central PMCID: PMC6342750.

Aguilar Pérez M, Bhogal P, Henkes E, Ganslandt O, Bäzner H, Henkes H. In-stent Stenosis after p64 Flow Diverter Treatment. Clin Neuroradiol. 2018 Dec;28(4):563-568. doi: 10.1007/s00062-017-0591-y. Epub 2017 May 9. PubMed PMID: 28488025; PubMed Central PMCID: PMC6245240.

Ultrasonic aspiration

Ultrasonic aspiration

Ultrasonic aspiration (UA) devices are commonly used for resecting intracranial tumors, as they allow for internal debulking of large tumors, hereby avoiding damage to adjacent brain tissue during the dissection. Little is known about their comparative safety profiles.

Henzi et al. from the University Hospital Zurich analyzed data from a prospective patient registry. Procedures using one of the following UA models were included: Integra® CUSA, Söring®, and Stryker® Sonopet. The primary endpoint was morbidity at discharge, defined as significant worsening on the Karnofsky Performance Scale. Secondary endpoints included morbidity and mortality until 3 months postoperative (M3), occurrence, type, and etiology of complications.

Of n = 1028 procedures, the CUSA was used in n = 354 (34.4 %), the Söring in n = 461 (44.8 %), and the Sonopet in n = 213 (20.7 %). There was some heterogeneity of study groups. In multivariable analysis, patients in the Söring (adjusted odds ratio (aOR) 1.29; 95 % confidence interval (CI), 0.80-2.08; p = 0.299), and Sonopet group (aOR, 0.86; 95 % CI, 0.46-1.61; p = 0.645) were as likely as patients in the CUSA group to experience discharge morbidity. At M3, patients in the Söring (aOR, 1.20; 95 % CI, 0.78-1.86; p = 0.415) and Sonopet group (aOR, 0.53; 95 % CI, 0.26-1.08; p = 0.080) were as likely as patients in the CUSA group to experience morbidity. There were also no differences for M3 morbidity in subgroup analyses forgliomas, meningiomas, and metastases. The grade (p = 0.608) and etiology (p = 0.849) of postoperative complications were similar.

Neurosurgeons select UA types with regard to certain case-specific characteristics. The safety profiles of three commonly used UA types appear mostly similar 1).



Henzi S, Krayenbühl N, Bozinov O, Regli L, Stienen MN. Ultrasonic aspiration in neurosurgery: comparative analysis of complications and outcome for three commonly used models. Acta Neurochir (Wien). 2019 Aug 3. doi: 10.1007/s00701-019-04021-0. [Epub ahead of print] PubMed PMID: 31377957.
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