Flow diverter | |
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![]() Common sites (intracranial) of saccular aneurysms (treated with flow diverter) | |
Specialty | Interventional neuroradiology |
ICD-10-PCS | Z95.828 |
A flow diverter is an endovascular prosthesis used to treat intracranial aneurysms. [1] It is placed in the aneurysm's parent artery, covering the neck, in order to divert blood flow and determine a progressive thrombosis of the sac. [2] Flow diverting stents consist of structural Cobalt-chrome or Nitinol alloy wires and often a set of radiopaque wires woven together in a flexible braid. [3]
Flow diverters are treatment for intracranial aneurysms alternative to endosaccular coil embolization, although the techniques can be combined, especially in large/giant aneurysms. It is mainly effective in wide neck unerupted saccular aneurysms, that are difficult to coil because of the tendency of the coils to fill the parent artery (referred to as prolapse). Another situation is fusiform shape or circumferential aneurysms. [4] Prior to flow diverters many intracranial aneurysms went untreated. [5] Flow diverters can be placed in the parent vessel or within the aneurysm, which are called intrasaccular flow diverters [6] [7] . These devices can be used to treat aneurysms by doing a cerebral angiogram via femoral artery or radial artery access [7] .
The efficacy of flow diverters can be evaluated using a grading system developed by researchers at Oxford Neurovascular and Neuroradiology Research Unit (Kamran et al. 2011), commonly referred to as flow diverter grading system or Kamran grading system. [8] After receiving a cerebral flow diverter, patients are placed on dual antiplatelet therapy for an extended period of time to reduce the likelihood of peri-procedural and post-procedural thromboembolic complications. [ medical citation needed ]
The degree of aneurysm occlusion is graded on a five-point scale from 0 (no change in the endoaneurysmal flow) to 4 (complete obliteration of the aneurysm). The patency status of the parent artery is evaluated on a three-point scale, from no change in the parent artery diameter to parent artery occlusion. This grading system is used in clinical practice. It has also been used and adapted by researchers to evaluate and report the effectiveness of flow diverters in general. [9]
An arteriovenous malformation (AVM) is an abnormal connection between arteries and veins, bypassing the capillary system. Usually congenital, this vascular anomaly is widely known because of its occurrence in the central nervous system, but can appear anywhere in the body. The symptoms of AVMs can range from none at all to intense pain or bleeding, and they can lead to other serious medical problems.
A cerebral arteriovenous malformation is an abnormal connection between the arteries and veins in the brain—specifically, an arteriovenous malformation in the cerebrum.
An intracranial aneurysm, also known as a cerebral aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel.
An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus for clot formation (thrombosis) and embolization. As an aneurysm increases in size, the risk of rupture, which leads to uncontrolled bleeding, increases. Although they may occur in any blood vessel, particularly lethal examples include aneurysms of the Circle of Willis in the brain, aortic aneurysms affecting the thoracic aorta, and abdominal aortic aneurysms. Aneurysms can arise in the heart itself following a heart attack, including both ventricular and atrial septal aneurysms. There are congenital atrial septal aneurysms, a rare heart defect.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Vascular surgery is a surgical subspecialty in which vascular diseases involving the arteries, veins, or lymphatic vessels, are managed by medical therapy, minimally-invasive catheter procedures and surgical reconstruction. The specialty evolved from general and cardiovascular surgery where it refined the management of just the vessels, no longer treating the heart or other organs. Modern vascular surgery includes open surgery techniques, endovascular techniques and medical management of vascular diseases - unlike the parent specialities. The vascular surgeon is trained in the diagnosis and management of diseases affecting all parts of the vascular system excluding the coronaries and intracranial vasculature. Vascular surgeons also are called to assist other physicians to carry out surgery near vessels, or to salvage vascular injuries that include hemorrhage control, dissection, occlusion or simply for safe exposure of vascular structures.
In human anatomy, the radial artery is the main artery of the lateral aspect of the forearm.
Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Symptoms may include a severe headache of rapid onset, vomiting, decreased level of consciousness, fever, weakness, numbness, and sometimes seizures. Neck stiffness or neck pain are also relatively common. In about a quarter of people a small bleed with resolving symptoms occurs within a month of a larger bleed.
Intracranial hemorrhage (ICH), also known as intracranial bleed, is bleeding within the skull. Subtypes are intracerebral bleeds, subarachnoid bleeds, epidural bleeds, and subdural bleeds. More often than not it ends in a lethal outcome.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
A carotid-cavernous fistula results from an abnormal communication between the arterial and venous systems within the cavernous sinus in the skull. It is a type of arteriovenous fistula. As arterial blood under high pressure enters the cavernous sinus, the normal venous return to the cavernous sinus is impeded and this causes engorgement of the draining veins, manifesting most dramatically as a sudden engorgement and redness of the eye of the same side.
Joshua B. Bederson is an American neurosurgeon, Leonard I. Malis, MD/Corinne and Joseph Graber Professor of Neurosurgery, and Chair of Neurosurgery at the Mount Sinai Health System in New York City. He is a Fellow of the American College of Surgeons and an attending neurosurgeon at The Mount Sinai Hospital and Elmhurst Hospital in Elmhurst, Queens.
Vein of Galen aneurysmal malformations(VGAMs) and Vein of Galen aneurysmal dilations (VGADs) are the most frequent arteriovenous malformations in infants and fetuses. A VGAM consists of a tangled mass of dilated vessels supplied by an enlarged artery. The malformation increases greatly in size with age, although the mechanism of the increase is unknown. Dilation of the great cerebral vein of Galen is a secondary result of the force of arterial blood either directly from an artery via an arteriovenous fistula or by way of a tributary vein that receives the blood directly from an artery. There is usually a venous anomaly downstream from the draining vein that, together with the high blood flow into the great cerebral vein of Galen causes its dilation. The right sided cardiac chambers and pulmonary arteries also develop mild to severe dilation.
Endovascular coiling is an endovascular treatment for intracranial aneurysms and bleeding throughout the body. The procedure reduces blood circulation to the aneurysm through the use of microsurgical detachable platinum wires, with the clinician inserting one or more into the aneurysm until it is determined that blood flow is no longer occurring within the space. It is one of two main treatments for cerebral aneurysms, the other being surgical clipping. Clipping is an alternative to stenting for bleeding.
Interventional neuroradiology (INR) also known as neurointerventional surgery (NIS), endovascular therapy (EVT), endovascular neurosurgery, and interventional neurology is a medical subspecialty of neurosurgery, neuroradiology, intervention radiology and neurology specializing in minimally invasive image-based technologies and procedures used in diagnosis and treatment of diseases of the head, neck, and spine.
Saleem Abdulrauf is an American physician specializing in neurosurgery in Washington, DC, who has helped develop high-flow brain bypass surgery, a less invasive procedure for treating intracranial aneurysm than methods used previously.
William T. Couldwell M.D., Ph.D., a neurosurgeon, was born in British Columbia, Canada. He is Professor and Chairman of the Department of Neurosurgery at the University of Utah, a position he assumed in 2001.
Alexander Coon is an American neurosurgeon who is the Director of Endovascular and Cerebrovascular Neurosurgery at the Carondelet Neurological Institute of St. Joseph's and St. Mary's Hospitals in Tucson, Arizona. He was previously the Director of Endovascular Neurosurgery at the Johns Hopkins Hospital and an Assistant Professor of Neurosurgery, Neurology, and Radiology at the Johns Hopkins Hospital. He is known for his work in cerebrovascular and endovascular neurosurgery and his research in neuroendovascular devices and clinical outcomes in the treatment of cerebral aneurysms, subarachnoid hemorrhage, and AVMs.
Venko Filipče is a Macedonian neurosurgeon and the former health minister of North Macedonia from 2017 to 2022. He served as the health minister during the COVID-19 pandemic in North Macedonia. In addition to his work as a surgeon and health minister, Filipče has also published scientific articles in medical neurosurgical journals.
Luca Paolo Eugenio Regli is a neurosurgeon and full professor and chairman of the Department of Neurosurgery of the University Hospital of Zürich since October 2012. He is the son of Franco Regli, a Swiss professor of neurology and founder of the Foundation Franco Regli for the Research in the Field of Neurodegenerative Diseases.