Wide-necked bifurcation cerebral aneurysms have always been
challenging to treat and have historically required either a surgical clip,
stent, or balloon-assisted coil embolization. This predicament to preserve
major bifurcation vessels while achieving a double occlusion of the aneurysm
led to the development of Woven
EndoBridge (WEB) aneurysm embolization system. The WEB device
is an intrasaccular braided wire designed to disrupt blood flow through the aneurysm
ostium for the treatment of intracranial wide-neck bifurcation aneurysms. Reconstructing
the aneurysm neck interface with a low-porosity metal mesh, the WEB
system initiates thrombosis and provides a robust lattice for subsequent
nonendothelial tissue overgrowth. The tightly packed, permanent nitinol-based
mesh material comes in different variants to treat a broad range of aneurysms,
including bifurcation-type morphologies, without placing adjacent perforating
arteries at risk.
The WEB System is a first-to-market,
innovative, and extensive intrasaccular solution that causes prompt aneurysm
occlusion, which makes it appropriate for the treatment in ruptured aneurysms.
The WEB embolization system is a self-expanding mesh, composed of
inner and outer braids held together by the proximal, middle, and distal
radiopaque markers. Depending on the device, the inner and outer layer of the
mesh consists of 108 0r 144 wires, so the blood flows into the WEB-embolized
aneurysm has to encounter two layers of 216 or 288 wires arranged at a distance
of 106 or 147 μm, respectively. Like other conventional endovascular coil
systems, WEB implant is also deployed using microcatheters. The device system
consists of a controller, that is used to detach the device from the delivery
wire once positioned appropriately.
The Woven EndoBridge aneurysm embolization
system is the only FDA-approved device for the treatment of
ruptured and non-ruptured wide-necked aneurysms. Small aneurysms with angulated
access can be the most challenging but the WEB solution has a variant for them
as well. With the greater softness of the device, the WEB 17 system is
ideal for aneurysms with extreme angulation at the parent/aneurysm interface.
The WEB 17 system is placed through steam shaping the VIA microcatheter,
which has great flexibility and helps in catheterizing aneurysms.
The WEB Aneurysm Embolization System is
indicated for use in middle cerebral artery (MCA) bifurcation, internal carotid
artery (ICA), anterior communicating artery (ACA), and basal artery apex in
adult patients. The device is FDA-approved for the treatment of intracranial
aneurysms with dome diameter ranging from 3 mm to 10 mm and
neck size equal to or greater than 4 mm. However, the device is not to be used
in patients with known active bacterial infection and hypersensitivity to
nickel. The Woven Endobridge (WEB) system cannot be used in large or giant
aneurysms greater than 10 mm because the largest device diameter is 11X9.6
mm.
WEB system is a safe and effective treatment
option, that provides excellent clinical outcomes with fast procedural time and
limited radiation exposure. Demonstrating 84.6% adequate occlusion and
extraordinary safety profile for aneurysms that are challenging to treat with
standard embolization devices, the WEB system has become a valuable alternative
for physicians to treat bifurcation aneurysms. Some other diagnostic
interventions include the use of small metal clips on the neck of the aneurysm,
embolic coils, flow disruptor stents with the help of a catheter in the blood
vessel. Patients who cannot undergo surgical clipping can opt for the new and
unique intravascular device, WEB system to treat intracranial wide-neck
bifurcation aneurysms.
Once placed inside the aneurysm sac, the WEB
device’s proprietary microbraid technology self-expands by gently
pushing off the nearest wall into the center of the aneurysm to conform to the
sac shape without needing other devices. From device insertion to withdrawal,
the procedure takes around 20.9 minutes on average. The
single-device treatment alternative to endovascular coils is a long-lasting
treatment for intracranial aneurysms, creating a scaffold by bridging the
aneurysm neck for disrupting blood flow. The WEB system has been used safely in
over 10,000 cases throughout the world, but the device is available for sale in
the only US and Japan currently.
The WEB system device has a high success rate,
but it is not ideal for everyone. The device is not suitable to treat an
intracranial aneurysm in patients who
· Are less than 18 years old
· Are not capable to undergo general
anesthesia
· Are pregnant
· Has a renal insufficiency
· Does not have aneurysm with dome-to-neck
ratio ≥ 1
· Is non-compliant or presents an unstable
psychiatric history
The WEB device has evolved from a dual-layer
version to high visibility single-layer versions such as WEB SLS and WEB
SL. While WEB SLS treats bifurcation aneurysms with a fundus to create a
spherical appearance, the WEB SL device is barrel-shaped to
accommodate cylindrical bifurcation aneurysms in which the neck width and
diameter are similar. Appropriate WEB device selection is important for the
success of the treatment so physicians can choose between SL or SLS based on
the aneurysm size, neck, and dome morphology. The WEB device is retrievable and
can be exchanged for a different size or shape if the original is not optimal
for the aneurysm. Inadequate compression is associated with an
increased risk of aneurysm recurrence therefore the device width should be
oversized compared to the diameter of the aneurysm in order to release radial
force throughout the surface of the aneurysm wall.
Dual antiplatelet administration is not required with the WEB devices
whereas open surgical clipping needs dual antiplatelet agents for adequate
occlusion of the rupture site. However, in some cases with large aneurysm neck,
antiplatelet medications can be initiated. Also, for elective embolization,
pre-treatment with effective antiplatelet therapy may lower the risk of thromboembolic
complications. Post-procedure, the patients are often administered low-dose
aspirin rather than antiplatelet therapy in many straightforward cases.
Complications
The WEB deployment involves a risk of rupture
of aneurysm however, it is a rare occurrence. Usually, the rupture can occur
when the constrained WEB device first exists the microcatheter or an
unanticipated forward pressure is stored within the VIA microcatheter and
delivery system. Once the device is deployed inside the aneurysm, there is a
very unlikely probability of rupture. The patient might develop aneurysm
recurrence and require retreatment in case of device migration and WEB
device compaction. Device migration happens when the WEB device transcends
from the initial site of placement into the aneurysm sac, but the size of the
device remains unchanged. This phenomenon occurs either due to under-sizing the
device or an improperly chosen device or partially thrombosed aneurysms. WEB
device compaction means a decrease in height of the device with deepening of
the marker recess at both sides, which results from cicatrization within the
aneurysm fundus.
Other EndoSaccular Flow Disruptor Devices
PulseRider
The PulseRider is another novel endovascular device designed for
treating wide-necked bifurcation aneurysms. Just like the WEB embolization
system, the PulseRider is self-expanding nitinol impact, which acts as a neck
bridge to disrupt blood flow. The PulseRider has a unique frame configuration
and is specifically designed to preserve luminal patency and hemodynamic flow
through the parent vessel bifurcation.
pCONus
The pCONus is an electrolytically-detachable and re-sheathable,
self-expanding stent-like device that deploys within the aneurysm and bridges
its neck. The shorter shaft provides reliable stability and a stent-like
structure secure anchoring and long-term stability. pCANvas is a new
derivative of the pCONus with an added feature of membrane between each petal
fabricated to augment the neck-bridging effect.
The durability and safety of endovascular treatment for
intracranial aneurysms can be enhanced by eliminating the need to catheterize
branch vessels for deployment, which may be considered advantages of the
PulseRider, pCONus, and pCANvas devices and limitation of WEB embolization
system. Application of the PulseRider or pCONus offers two potential advantages
for aneurysm neck reconstruction such as eliminating the need for catheterizing
blood vessels while deploying the devices in the aneurysm and lack of dual
antiplatelet therapy. However, intrasaccular flow disruption at the aneurysm
neck without any neck reconstruction devices simplifies the treatment and
reduces the number of steps to the procedure.
Conclusion
The treatment modalities for endovascular treatments of
intracranial aneurysms have evolved in the past three decades. The detachable
balloon was the first reliable technique, but a high rate of secondary
deflation was a major limitation associated with the procedure. Then, fiber
coils were introduced to overcome the problems of a detachable balloon, but
they could not be replaced or removed in case of the inadequate shape of the
coils. Therefore, embolization with flexible platinum coils has become the
widely used procedure to treat intracranial aneurysms, and there is no better
device than the WEB embolization System to generate safe and sound results.
According to TechSci report, “Global
Brain
Implants Market By Product Type (Deep Brain
Stimulators, Spinal Cord Stimulators, Vagus Nerve Stimulators) By Application
(Chronic Pain, Epilepsy, Parkinson’s Disease, Depression, Essential Tremor,
Alzheimer’s Disease) By End User (Hospitals & Clinics, Ambulatory Surgery
Centers, Others) By Region, Competition Forecast & Opportunities, 2026”, the global brain implants market is
anticipated to grow at a significant rate during the forecast period. The
growth can be attributed to the rising population prone to neurological
disorders and technical advances in brain implants.
Another TechSci research report on “Global
Deep
Brain Stimulation (DBS) Devices Market By Product
Type (Single-channel Deep Brain Stimulator, Dual-channel Deep Brain
Stimulator), By Type (Rechargeable, Non-Rechargeable), By Application
(Obsessive Compulsive Disorder, Parkinson’s Disease, Essential Tremor,
Epilepsy, Dystonia, Others), By End User (Hospitals, Ambulatory Surgical
Centers (ASCs), Neurological Clinic, Research Centers), By Region, Forecast
& Opportunities, 2025”, the global
deep brain stimulation devices market is anticipated to grow at a steady rate
during the forecast period. The growth can be attributed to factors such as
growing incidences of neurological disorders, rising prevalence of lifestyle
diseases, and increasing investment in R&D activities in the neurological
sector.