interventional neurovascular radiology


Medical technology with its quantum growth has changed the very facet of healthcare. Interventional neurovascular radiology in keeping with this advancement, has altered the approach of cerebrovascular disease management. Our Interventional Neurovascular Radiology department at The Kauvery Institute of Orthopaedic and Neurosciences is au courant in knowledge, expertise and equipment, to better serve our patients under our care.

Our specialist interventional neurovascular radiologists use a minimally invasive technique to diagnose and manage neurovascular diseases and spine disorders. Interventional Neurovascular Radiological procedures provide an alternative to traditional surgical procedures, for disorders such as strokes, cerebral aneurysms and back pain (use of endovascular procedure to reach lesions). Our radiologists also use the most advanced imaging systems to provide evaluations, diagnosis and treatment options for a gamut of neurological disorders.

Our specialized and expert interventional neurovascular radiologists focus solely on the specific conditions pertaining to the brain and the spinal cord. They are accomplished in the use of image-guidance procedures and our specialists are on call 24x7, 365 days of the year. Our interventional neurovascular radiologists work in tandem with our multidisciplinary team at The Kauvery Institute of Orthopaedic and Neurosciences to provide the best care and treatment to patients afflicted with neurovascular disorders.

Interventional Neurovascular Radiology is also known by these various terminologies:

  • Interventional Radiology (IR)
  • Vascular Interventional Radiology
  • Surgical Radiology

Interventional Neurovascular Radiology until recently was a sub-specialty. Now as an independent specialty, it involves minimally invasive, image-guided procedures to diagnose and treat neurovascular disorders. Our range of service include:

  • Stroke-Mechanical Thrombectomy
  • Brain Aneurysm Coiling
  • Brain AVM Embolization
  • Head and Neck Tumour Preoperative Embolization
  • Spinal Vascular Malformation Embolization
  • Carotico- Cavernous Fistula Embolization
  • Stroke-Mechanical Thrombectomy

    Mechanical Thrombectomy is a contemporary, neurovascular, interventional radiological procedure developed for treatment of embolic stroke. The interventional mechanical treatment of stroke involves use of devices such as catheters and stent retrievers. This is a very safe and quick result oriented treatment, offered by only 6 renowned hospitals in Chennai, of which The Kauvery Institute of Orthopaedic and Neurosciences is one.

    Our specially trained and skilled interventional neurovascular radiologists perform this procedure, using small wires and micro-catheters, measuring 0.0254 in diameter, to deliver thrombus dissolving medications, right into the blood clot. The immediate outcome of this procedure is that blood flow is immediately resumed. In comparison to pharmaceutical thrombolytic medications which take anywhere from 2 hours or more, to dissolve a blood clot, the mechanical thrombetomy effect is immediate. This procedure can be performed on a patient suffering from acute thromboembolic stroke, if brought into our hospital within 6 hours of the attack.

    Our Interventional Neurovascular Radiology department is equipped with some of the most avant-garde mechanical thrombectomy devices and our neurovascular radiologists have all been trained to use them expertly. Since the 1980s and 1990s, traditional surgery was done away with as there were more risks involved and ever since then removing blood clots from the brain in patients suffering from ischemic strokes, through Mechanical Thrombectomy, has been by this new modality.

    Catheter Directed Thrombolysis

    Any interventional treatment involves minimally invasive procedures. Likewise the catheter directed thrombolysis, is a procedure where very small incisions are made, as opposed to the large incisions that are required in traditional surgery. This catheter directed thrombolysis treatment acts to dissolve aberrant blood clots in blood vessels (arteries and veins), in order to boost the flow of blood and prevent tissue and organ damage. An attack of stroke, if left untreated can culminate in dire consequences.

    Before undergoing the minimally invasive operation, a blood test will be done to check whether your blood clots normally. The treating doctor should be advised of all medications, such as blood thinners and other medications taken by the patient, who is undergoing the treatment. This is an inpatient procedure and prior to the treatment the Interventional Neurovascular Radiologist (INR) will first perform an angiogram. After studying the angiogram, our specially trained neurovascular nurses or technologists will start an IV with moderate sedation. Using our state-of-the-art image guided systems (Fluoroscopy or live x-ray), our Interventional Neurovascular Radiologist will insert a catheter into the femoral artery, after making a tiny incision, and will advance the catheter to the region where the embolus is present. A clot dissolving medication is then injected through another smaller catheter that is inserted into the first catheter. The medication is directly delivered to the embolus. This is a quick procedure (completed within an hour) and does not involve long hospital stays.

    Stent Retrievers in Mechanical Thrombetomy

    Another device that our Interventional Neurovascular Radiology department at The Kauvery Institute of Orthopaedic and Neurosciences uses, is the stent retriever. These devices are now being increasingly used to restore and improve blood flow in acute embolic stroke patients. Stent retrievers have the capability of quickly restoring blood flow and also have the ability to retrieve large, intracranial blood clots, effectively.

    A stent retriever is deployed to the distal site where the embolism is present, through a micro-catheter. The stent instantly creates a channel (a temporary bypass), to improve the blood flow, while compressing the thrombus.

  • Brain Aneurysm Coiling

    The abnormal ballooning of an artery carrying blood to the brain is an intracranial or brain aneurysm. An intracranial aneurysm is also known as a brain aneurysm or cerebral aneurysm. The surge of blood through the arteries carrying blood to the brain is at high pressure and an aneurysm develops when the arterial walls weaken, creating a bulge (an abnormality) or a balloon like structure.

    Behavioral patterns of an aneurysm include:

    • Aneurysms can either inflate or apply pressure on the structures in the brain
    • If an aneurysm ruptures, the blood will seep out of the blood vessel, under high pressure, either directly into the brain or into the fluid surrounding the brain
    • Causes sudden and severe headache commonly
    • Sometimes stiffness of the neck may also be there, together with vomiting
    • Causes sensitivity to normal daylight
    • Rarely an aneurysm, can disrupt vision, causing double vision

    Our Interventional Neurovascular Radiology department at The Kauvery Institute of Orthopaedic and Neurosciences provides both magnetic resonance imaging (MRI) and computed tomography (CT scan) services to scan, diagnose and treat brain aneurysms.

    Discovery of aneurysms that are yet to rupture are generally found when a patient undergoes a CT scan or MRI procedure for another reason. Such aneurysms which are yet to rupture, can be treated by the Coil Embolization process, provided the diagnosis is favorable that the aneurysm will not rupture or pose a risk for rupturing.

    In an endovascular coiling procedure or endovascular embolization, as it is otherwise known as, blood flow to the aneurysm is blocked by the insertion of a long thin tube called a catheter, into the artery located in the groin, and is then advanced forward, with the help of a fluoroscopy apparatus (live x-ray), to the artery that is afflicted. After the catheter is in place, a smaller tube is then passed through the catheter, into the aneurysm and a length of platinum coils are wound into the aneurysm. With the help of the live x-ray imaging system, the radiologist will continue to pack the aneurysm until it is filled up and the blood flow to the aneurysm is brought down to a trickle. Slowly the blood starts to clot around the platinum coils and stops in due time. Blocking the blood flow from entering the aneurysm, will prevent it from leaking or rupturing. This procedure normally takes around 2 or 3 hours.

    An endovascular embolization is a minimally invasive procedure and does not need to be a surgical procedure.

    The advantage of undergoing an endovascular embolization procedure as against an endovascular aneurysm clipping, is that the skull need not be operated upon, consequently saving on hospitalization and recovery time, which is shorter than that involved in traditional surgery. Whether a patient is qualified to undergo this procedure, however, will depend on the patient’s medical history and other factors.

    During an evaluation and diagnostic endovascular coiling procedure, our skilled Interventional Neurovascular Radiologists may also use some of our other state-of-the-art equipment (apart from the Fluoroscopy), such as, an electroencephalogram (EEG), cerebral arteriogram, magnetic resonance imaging (MRI), Doppler Ultrasound, Computer Tomography (CT scan), Positron Emission Tomography (PET scan) and X-rays of the skull and craniotomy.

  • Brain AVM Embolization

    Brain AVM or Arteriovenous Malformations are the result of birth defects in the brain’s circulatory system, that are formed during the embryo or fetal stage.

    Blood vessels called the arteries supply oxygenated blood to the different parts of the body and the brain. The blood flow through the arteries is pumped at high pressure. The de-oxygenated blood is taken away by the venous system (part of the circulatory system) back to the heart to be re-oxygenated. The blood that flows back into the veins is at a much reduced pressure in comparison to the pressure in the arteries. The walls of the arteries are thick to withstand the high pressure of the blood being pumped through it and the walls of the veins are thin, as they do not have to withstand the same pressure as the arteries. The arteries further branch out into smaller tubes called the capillaries, which carry the blood to the cells. As the blood flows through the capillaries, the pressure of flow slows down and by the time it reaches the veins the pressure is adequately adjusted for the veins to bear.

    In an arteriovenous malformation, the capillaries that connect the arteries and veins in the brain are absent and much larger vessels connect the arteries and the veins, consequently there is no bridge to slow down or block the high flow of pressure of blood into the veins. These larger vessels that are in place of the capillaries are called shunts and the network of shunts is called the nidus. Though the nidus replaces the capillary network, it does not function in the same way as the capillary network and therefore the veins experience the same high pressure of blood flow as the arteries do. Since the walls of the veins are thin, the flow of blood at a higher pressure ruptures the walls of the vein and causes a leak or bleeding in the brain. This bleeding is referred to as hemorrhagic stroke.

    There is no known reasons for the formation of arteriovenous malformations. They do occur during the fetal and embryonic stage, but do not cause any bleeding in a newborn generally, though there have been some rare cases. It occurs equally in both men and women and is considered to be hereditary.

    If left untreated, a hemorrhagic stroke can cause death or lead to other visible disabilities such as, neurological disorders like vision or speech problems, numbness or weakness of parts of the body and seizures. Excess bleeding can even lead to death.

    The onset of a sudden and severe headache generally is the precursor to an AVM, accompanied by nausea and vomiting. A Computed Tomography or CT scan will be performed to evaluate and diagnose the presence of an AVM. Once the presence of an AVM is confirmed, then an angiography and an MRI is performed to further localize the exact region the AVM is present in.

    An AVM can be treated in three ways, by surgery, radiation or by neuro-endovascular embolization. The neuro-endovascular embolization is performed by our experienced Interventional Neurovascular Radiologists, by blocking the malformed nidus. Our radiologists will perform an angiogram, which is not a surgical procedure, but a minimally invasive procedure. It is performed by inserting a small plastic tube or catheter into the femoral artery or through the groin, and navigated through into the shunts of the AVM. An injection is administrated through the catheter to block the shunts. Since the shunts are merely connections between the arteries and the veins they do not serve any real purpose, consequently blocking them will not adversely affect the patient.

  • Head and Neck Tumour Preoperative Embolization

    Tumours or carcinoma growth in the brain and neck are supplied with a large amount of blood. Before performing any surgical procedures on a patient diagnosed with brain or neck tumour, draining the blood out from the tumours will prevent bleeding and any risks that could possibly arise, during surgery. A planned blockage or embolization of the blood vessels helps the neurosurgeon to expeditiously execute the surgical procedure and also the embolization procedure averts the necessity for blood transfusion, during the surgical procedure.

    The Head and Neck Tumour Preoperative Embolization procedure is performed on:

    • Menigiomas (tumours that occur on the covering or meninges of the brain)
    • Glomus tumours or paragangliomas (tumours that occur on the nerves of the head and neck)
    • Juvenile nasopharyngeal angiofibromas (tumours of the nose)
    • Tumours of the spinal column (vertebral column)
    • Head and neck malignancies

    Preoperative embolization procedures are also performed on other types of tumors such as:

    • Hypervascular Metastases
    • Schwannomas
    • Esthesioneuroblastomas
    • Plasmacytomas
    • Hemangiopericytomas
    • Chordomas
    • Rhabdomyosarcomas

    Our experienced and comprehensive team of Interventional Endovascular Radiologists, Neurologists, Neurosurgeons, Physicians, Specialists and other care givers coordinate to provide the best preoperative evaluations and treatment plans for patients diagnosed with head or neck tumours.

    Our multidisciplinary approach is the key to our multiple success in providing analytical and treatment strategies. We ensure that we carry out a detailed clinical examination and pre-surgical diagnosis.

    Pre-procedure, a contrast is enhanced through CT or MRI, to gather information on the bone, soft tissue and lesion locale. Prior to any intervention, we also study a detailed angiography, we then proceed to select the catheter. These steps ensure that we compartmentalize the location of the tumour and the surrounding cells and blood vessels and potentially identify dangerous anastomosis between the blood vessels supplying the tumour and the lesion itself.

    Preparatory to surgery, our Interventional Radiologists will insert a catheter into the femoral artery (artery in the upper leg/ thigh region) and another catheter, smaller in dimension to the first catheter, is inserted into the larger catheter and is threaded up through to the artery or arteries that are feeding the tumour with blood. An appropriate embolic material is injected, under continuous fluoroscopic guidance to clog the blood supply to the tumour. This procedure of blocking or clogging the blood supply is called embolization.

    There are many different types of embolic material available and depending on the type of tumour, the size of the tumor’s blood vessel, and where the tumor is located, an embolic material will be used. A preoperative embolization is generally performed a few days (24-72 hours) prior to the planned surgery, so that a paramount thrombosis of the blocked blood vessels develops and therefore cannot re-canalize or form collateral arterial canals.

    In cases where the blood supply needs to be blocked off from tunours on the bones of the spine, a needle is inserted directly into bone where the tumour is located and embolic material is injected to arrest the blood supply or even to annihilate the tumour.

    Embolic materials generally used in a preoperative embolization procedure are:

    • Embospheres (BioSphere Medical, Rockland, Mass)
    • Polyvinyl alcohol (PVA)
    • Liquid embolic agents (glue, ethylvinyl alcohol copolymer or EVOH
    • Irvine
    • Onyx or ev3
    • Gelfoam, Upppsala, Phadia, Sweden – gelatin sponge
  • Spinal Vascular Malformation Embolization

    The spinal cord in the central nervous system is the extension of the brain, connecting the nerves from the brain to the different parts of the body. Malformations in the human body’s network of blood vessels is caused when the arteries and veins are directly connected instead of through a network of capillaries that temper the flow of blood between the arteries and veins. Vascular malformations in the spine either encompass the spinal cord, the vertebrae or bones of the spine, the tissues surrounding the spinal cord within the spine, the soft tissue around the spinal column or sometimes it could be a combination of any one of these. Vascular malformations in the spine or around the spine can cause severe medical disorders such as weakness of the spine or in serious cases paralysis of the limbs partially or fully. Bleeding or hemorrhaging internally in the spine, or a stroke in the spinal cord, because of the presence of AVMs or DAVFs, can lead to abrupt or progressive loss of movement of the limbs which could be either temporary or permanent paralysis. Sometimes abnormal tingling sensations or total loss of any sensation in the limbs can also be experienced. In some cases loss of bladder and bowel control can be experienced, due to the presence of an AVM or DAVF.

    If such abnormalities are left untreated, in the advanced stages it could lead to permanent disability or in rare cases, death.

    Whether it is an AVM (arteriovenous malformation) or a DAVF (dural arteriovenous fistula), the malformed connections between the arteries and veins in the spinal column, both these conditions are abnormal.

    It is yet to be discovered as to why these abnormalities occur in the human system. However, it is supposed that these arteriovenous malformations or Dural arteriovenous fistula are congenital or inherited in certain people with a predisposition to developing this abnormality, which at some stage manifests itself. Arteriovenous Malformations are known to occur in older children and adults who are less than 50 years of age.

    AVMs and DAVFs are either treated by embolization or by a combination of embolization and open or traditional surgery. The embolization procedure is a minimally invasive procedure or keyhole procedure. It is performed through a very small incision the size of a keyhole and with the visual aid of a fluoroscopy (live x-ray). Special tiny coils, or sand like particles, or medical grade glue is directly injected into the nidus (abnormal canals) to occlude it.

    The procedure itself involves the placement of a catheter (a plastic tube of tiny dimensions) inside the femoral artery, guided by an image guidance system (fluoroscopy or live x-ray), to ensure that the catheter is in the spot where the AVM or DAVF is, before treating the AVM or DAVF, with coils or glue particles.

    Before scheduling a vascular malformation embolization procedure, an angiogram will be performed by our Interventional Neurovascular Radiologists, in order to pictograph a roadmap of the exact location of the vascular abnormality, the surrounding soft tissues, the location of the adjacent blood vessels and nerves.

    To perform an angiogram , a catheter is threaded through the femoral artery. A contrast or substance containing iodine, called iodinated contrast, is injected through the catheter to highlight the blood vessels on the x-ray images. Once the radiologist has the angiogram, then after studying the angiogram, the embolization procedure is planned.

  • Carotico- Cavernous Fistula Embolization

    Carotico or Carotid Cavernous Fistula (CCF), are similar to vascular abnormalities that occur in the brain and spinal cord. Carotid Cavernous Fistula occurs when the internal or external arteries supplying blood to the carotid artery (serves the eyes), the cavernous sinus and the veins, are directly connected. This is a sight robbing affliction, though not of life endangering proportions.

    In a carotid cavernous fistula, the absence of the fine network of capillaries to temper down the rush of blood from the arteries (due to the high pressure of blood flow in the arteries), directly into the veins puts the veins under great strain, as the veins drain out the blood at a lower pressure than the arteries.

    Diagnosis of CCF is often tricky as CCF can often present symptoms akin to conjunctivitis or any of the other ophthalmic disorders; this poses a problem as it considerably reduces the possibility of speedy diagnosis and treatment outcomes. Despite the masquerade by CCFs, at The Kauvery Institute of Orthopaedic and Neurosciences, the expertise of our Interventional Neurovascular Radiologists have been able to achieve 100 percent results in cases where early diagnosis and repairs were made. Further in our carotico-cavernous fistula embolization procedure we make use of such advanced technology as the endoscope, which has made treatment of the CCF considerably less risky.

    Carotico-cavernous fistulae are of two types – direct carotico-cavernous fistula and dural arteriovenous shunts.

    • Direct carotico-cavernous fistula occur when there is a tear or hole in the branch of the carotid artery, internally within the cavernous sinus. This tear or hole could occur due to any one of the following reasons:
    • Trauma such as a car accident or force applied to the head with a bat or club
    • Consequences of medical treatment, a iatrogenic consequence of a neurosurgical or interventional neuro-radiological procedure

    A spontaneous rupture, a carotid artery aneurysm rupturing in the cavernous sinus, the abnormal connection of the cavernous sinus and one or more meningeal branches of the internal carotid artery, or the external carotid artery, or even both, causes dural arteriovenous shunts. Affliction of carotico-cavernous fistula in both the arteries is quite common. The direct origin of dural CCF as on date is not known, but is believed to originate from the tinier arteriovenous shunts present in the dura that are normal modifications. It is presumed that for some abnormal reason, the formation of new blood vessels and their proliferation, produces these shunts, which generally act as barricades in the adjacent venous dural sinuses, otherwise known as cavernous sinus.

    Dural arteriovenous shunts have formed as a consequence of:

    • Systemic hypertension
    • Pregnancy
    • Atherosclerotic vascular disease
    • Any trauma on a minor scale
    • Ehiers-Danios Syndrome

    Carotico-cavernous Fistula is treated with the embolization procedure at our Kauvery Institute of Orthopaedic and Neurosciences, by our specialist interventional neurovascular radiologists, in conjunction with our comprehensive team of Ophthalmologist, Neurologist, Neurosurgeons, Physicians and other specialists. The procedure involves depositing platinum coils in the abnormal shunt, thereby preventing any direct blood flow from the carotid artery to the vein.

    The procedure is executed by inserting a catheter through the femoral artery and progressed to the location where the CCF is; the platinum coils are then injected through a second catheter, inserted into the first catheter. This treatment often reverses the symptoms of disability that led to the investigation in the first instance.

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