Endovascular and Cerebrovascular Neurosurgery
Endovascular Neurosurgery is a subspecialty of neurosurgery in which neurosurgical procedures are performed within blood vessels under fluoroscopic guidance. Performing a surgery within a blood vessel requires only a very small incision to access the artery, which allows for faster recovery and lower morbidity when compared to open surgery.
VCU has the regions only Neurosurgical Hybrid Operating Suite. As well as being equipped for both endovascular and open neurosurgical cases, this room allows surgeons to combine the two techniques or use them simultaneously. State-of-the-art fluoroscopy and 3D rotational angiography can now be incorporated into open surgery such as craniotomy for clipping of intracranial aneurysm or obliteration of AV fistulae to confirm the procedure is complete before the patient leaves the operating room. Endovascular techniques such as angioplasty and stenting can now be offered to patients in whom complicated anatomy or occlusion requires an operative approach to arteries. In addition, the hybrid operating suite offers the ability to perform intraoperative CT Scan which further enhances patient safety during minimally invasive procedures.
Dr. John Reavey-Cantwell and Dennis Rivet fall into the elite category of dual-trained neurosurgeons in the U.S. This special training in cerebrovascular and endovascular neurosurgery allows them to maximize the potential of the Neurosurgical Hybrid Operating Suite and offer patients the latest in neurovascular treatments.
John Reavey-Cantwell, MS, M.D.
Charlotte Gilman, RN
- Cerebral Aneurysm
- Arteriovenous malformations
- Carotid Stenosis
- Intracranial Stenosis
- Acute Ischemic Stroke
- Spinal Arteriovenous Malformations and Arteriovenous Fistulae
- Moyamoya Disease
- Cavernous Malformation
A cerebral aneurysm is a bubble or blister on the wall of an artery. This bubble or blister is weaker than the rest of the vessel and can burst, leading to a subarachnoid hemorrhage. Aneurysms are very rare in children and develop as a patient ages. Risk factors for developing aneurysms include smoking and untreated hypertension.
Patient may have no symptoms from an aneurysm. Often they are discovered on a scan of the brain performed for some other reason, for example after a car accident in which a patient has hit his or her head. Some aneurysms may cause compression of nearby nerves and be detected as doctors work to discover the cause of the nerve dysfunction, or palsy. The most common presentation of an aneurysm, however, is an acute rupture. Patients classically complain of the sudden onset of the worst headache of their life.
An aneurysm can be detected on a CT-angiogram, MRA or digital subtraction angiogram. Diagnosis of subarachnoid hemorrhage can be achieved with CT scan, but sometimes might require a lumbar puncture.
- Digital Subtraction Angiography: Most aneurysms will require an angiogram to determine the exact size and shape of an aneurysm in order to determine which modality is best for treatment.
- Craniotomy: A craniotomy is an operation during which the skull is opened. A craniotomy for aneurysm involves removing the bone on the side of the head of the lesion and exposing the blood vessel with the aneurysm. A small clip, approximately 5mm, is placed on the aneurysm neck to prevent blood from entering. The Neurosurgical Hybrid Operating Suite at VCU offers surgeons the ability to perform angiography during the operation to ensure the aneurysm is treated and no important vessels have been inadvertently occluded.
The picture on the left is a middle cerebral artery bifurcation aneurysm under high magnification. The picture in the middle shows the application of an aneurysm clip across the neck of the aneurysm. The picture on the right illustrates complete occlusion of the aneurysm neck and preservation of the distal middle cerebral artery branches.
The picture on the left is a clipped internal carotid artery aneurysm. The picture on the right is the same aneurysm viewed during fluorescein dye angiography. The white dye does not enter the aneurysm, demonstrating complete occlusion, while all of the important blood vessels fill well.
- Coil embolization: If an aneurysm is the right size and shape, platinum coils can be placed inside the aneurysm until blood can no longer enter the aneurysm. The size and shape of aneurysms that are appropriate for this treatment has been greatly increased in the past few years by the advent of many stents and balloons that can assist in these procedures. Coils can compact over time and a patient needs to have follow-up angiograms after their coiling to ensure that their coils are not compacting, which might require further treatment.
In the first picture below, a microcatheter has been placed a PCOM artery aneurysm. In the picture on the right, the aneurysm has been successfully coiled and is no longer filling with contrast or blood.
- Liquid embolization: A small subset of aneurysms can be treated with liquid embolics. Filling an aneurysm with a thick, high viscosity liquid, like a spackle, allows for complete occlusion of the lumen and complete filling of irregular shapes. This therapy also theoretically decreases the risk of compaction.
In the first pair of pictures on the left, a superior hypophyseal aneurysm and its irregular neck have been occluded with a liquid embolic. In the two pictures on the right, 3D angiography reveals complete obliteration of an ophthalmic artery aneurysm performed with a liquid embolic.
- An aneurysm does not need to be treated emergently. If an aneurysm has ruptured, however, it needs to be treated within the first day or so to prevent the aneurysm from bleeding again.
Brain aneurysm foundation: www.bafound.org/
Brain arteriovenous malformation (AVM) is an abnormal tangle of blood vessels in which arteries drain directly into veins without an intervening capillary bed. Exposing thin-walled veins directly to the pressure present in cerebral arteries puts the patient at risk of bleeding and seizures. Patients are born with AVM�s and the exact cause is unknown.
Some AVMs can cause seizures. The large, abnormal vessels associated with AVMs can also cause compression of cranial nerves leading to face pain, facial spasm, or throat pain. The symptoms of an AVM rupture include severe headache, nausea and vomiting, blurred vision, stiff neck, or loss of consciousness, paralysis, weakness, numbness, vision problems, balance or coordination problems, or speech difficulties.
The diagnosis of a brain AVM can be made by a CT scan or an MRI. Digital subtraction angiography is required to fully understand the angio-architecture of a patient�s lesion and formulate a treatment plan.
The MRI scan on the left reveals a left thalamic AVM. A tangle of vessels, or nidus, is represented by black dots or flow voids, draining into dilated veins, represented by the large black circles. The picture on the right is a CT-angiogram illustrating the same AVM. The nidus is the ball of white lines and the drain veins are the thick, bright white structures in the middle of the patient�s head.
- Digital Subtraction Angiography: All AVMs require an angiogram to fully classify the lesion and to recommend proper treatment.
- Embolization: Vessels feeding AVMs may be purposefully plugged using glue or other polymers. Embolization may be performed to limit blood loss during operative resection, decrease the size of a lesion for radiosurgery, or as a stand-alone cure if the entire lesion can be safely embolized. Whether or not embolization can offer a complete cure remains controversial.
The digital subtraction angiogram on the left reveals a small nidus in the center of the picture and an early draining vein on the right of the picture. The post-embolization digital subtraction angiogram on the right demonstrates no filling of the nidus and no early draining vein.
- Stereotactic radiosurgery: Lesions less than 3cm can be radiated using the LINAC system at VCU. The exact mechanism by which radiation causes vessel occlusion is not understood. It can take up to three years for stereotactic radiosurgery to be completely effective.
- Microsurgical resection: Certain AVMs can be removed surgically, offering the patient the chance of a complete cure. The Neurosurgical Hybrid Operating Suite at VCU offers surgeons the ability to perform angiography during the operation to determine what AVM remains and when resection is complete.
Carotid stenosis is a narrowing of the carotid artery. This can be caused by a vessel dissection as the result of a trauma, but is most often caused by a build-up of atherlosclerotic debris, or plaque, at the bifurcation of the common carotid when it branches into the internal and external carotid artery on either side of the neck. A piece of this plaque can break off and follow the blood flow into the brain where it may cause a temporary stroke, called a TIA, or a permanent occlusion, or stroke.
Carotid stenosis can develop without any symptoms. Sometimes a doctor can hear an abnormal sound when listening to carotid arteries with a stethoscope. A patient may experience blurred vision, paralysis, weakness, numbness, vision problems, balance or coordination problems, or speech difficulties. If these symptoms resolve quickly, the incident is called a transient ischemic attack, or TIA. If they persist, it is called an ischemic stroke. Most often, carotid stenosis is discovered when a patient has a stroke or TIA and imaging of the neck is obtained.
Carotid stenosis can be diagnosed by ultrasound, CT-angiogram, MRA, or digital subtraction angiography. The degree of the stenosis will determine if the artery requires treatment.
- Carotid endarterectomy: Carotid endarterectomy is an operation that involves an incision on the neck. Once the carotid artery is exposed, it is opened, the plaque is removed, and the artery is sewn back up. The picture below is an intra-operative picture of an exposed carotid artery during a carotid endarterectomy.
- Carotid stenting with distal protection device: Carotid stenting with a distal protection device involves placing a stent at the carotid bifurcation that increased the space inside the artery for blood to flow through. A distal protection device is a small umbrella that is placed beyond the stent that can �catch� any debris knocked loose during stent deployment. It is removed after the case.
The pictures below are the pre- and post-stenting angiogram.
Intracranial stenosis is a narrowing of the arteries in the brain. This develops over a patient�s lifetime. Narrowing can be moderate or severe and whether or not treatment is recommended depends on symptoms and the exact location of the lesion.
Intracranial stenosis can develop without any symptoms. The most common symptoms are TIA or stroke. A patient may experience blurred vision, paralysis, weakness, numbness, vision problems, balance or coordination problems, or speech difficulties. If these symptoms resolve quickly, the incident is called a transient ischemic attack, or TIA. If they persist, it is called an ischemic stroke.
Intracranial stenosis can be diagnosed by transcranial ultrasound, CT-angiogram, MRA, or digital subtraction angiography. A patient will require a digital subtraction angiogram to determine if the stenosis can be safely and effectively treated.
- Medical Therapy: Recent research has demonstrated that anti-platelet therapy alone is just as effective in preventing further TIA and stroke than thinning the blood with warfarin and much safer.
- Angioplasty and stenting: Angioplasty is a procedure in which a small balloon is inflated in a narrow artery to expand it. Stenting involves placing a tube made of metal mesh in the narrow segment of the artery to hold it open. These are most often used in combination.
The pictures below are the pre- and post-stenting angiogram of a tightly stenosed middle cerebral artery.
An ischemic stroke occurs when a blood vessel in the brain becomes occluded. It is sometime also referred to as a cerebral vascular accident (CVA.) The part of the brain that was relying on the vessel that has become occluded for blood flow will cease to function properly. If the occlusion is not treated, that part of the brain will infarct, or die, within a period of hours.
A patient may experience blurred vision, paralysis, weakness, numbness, vision problems, balance or coordination problems, or speech difficulties. If these symptoms resolve quickly, the incident is called a transient ischemic attack, or TIA. If they persist, it is called an ischemic stroke. If you suspect someone is having a stroke, you should call 911 immediately. EMS will know which hospital nearby is a stroke center.
Ischemic stroke can be diagnosed on a CT scan. Further studies like CT-angiogram or MRI or MRA can give much more detailed information about exactly which vessel is occluded and exactly which brain is at risk for infarction.
- Intravenous tPA: If a patient arrives at the hospital within 3 hours of the onset of symptoms, the can receive an injection of tissue plasminogen activator (tPA.) This drug dissolves clots. Patients must have a CT scan of the head in order to receive tPA to make sure the patient is not suffering from an intracranial hemorrhage, for which a clot-busting drug would be contraindicated.
- Thrombectomy: Patients who fail to improve after the administration of IV tPA or who are not candidates to receive the drug can undergo thrombectomy. Thrombectomy is an endovascular therapy in which surgeons thread a catheter within the blood vessels up to the occlusion. Next, one of many different devices is deployed to grab, suck, or remove the clot or occlusion. This re-establishes blood flow. The Neurosurgical Hybrid Operating Suite at VCU offers surgeons the ability to perform real-time CT scanning before, during and after the procedure to detect which brain has already infracted and is unsafe to revascularize or early detection of intracranial hemorrhage.
The picture on the left demonstrates an occluded middle cerebral artery. The picture on the right demonstrates successful thrombectomy on the same artery and filling of the middle cerebral artery.
The picture on the left demonstrates an occluded middle cerebral artery. The picture on the right demonstrates successful thrombectomy on the same artery and filling of the middle cerebral artery.
American Stroke Association: www.strokeassociation.org/STROKEORG/
Spinal arteriovenous malformations (AVMs) and spinal arteriovenous fistulae (AVFs) are vascular lesions of the spinal cord and surround nerves. These lesions are a combination of abnormal arteries and veins. The abnormal blood flow they cause can lead to hemorrhage or swelling of the spinal cord.
The exact symptoms differ depending on the spinal level at which the lesion is located. These lesions usually cause slow progressive decline in strength and sensation of the legs. Urinary and bowel continence can also be affected. Occasionally these lesions can present with sudden loss of function of the legs and this can be a sign of hemorrhage.
Spinal AVMs or AVFs can be diagnosed by MRI of the spine. A patient will require a digital subtraction angiogram to determine if the lesion is an AVM or AVF and what treatment is best. The MRI below of the cervical spine demonstrates a spinal AVF. The black dots behind and within the spinal cord represent dilated veins.
The digital subtraction angiogram below reveals an abnormal, early-filling spinal vein from a vertebral artery injection. This abnormal tangle of swollen veins in the spinal canal can cause spinal cord dysfunction.
- Embolization: Abnormal arteries can be filled with glues, polymers, or platinum coils. This prevents the abnormal blood flow that is causing the symptoms. Often times this treatment alone can treat a spinal AVM or AVF.
This digital subtraction angiogram reveals filling of serpiginous, dilated, spinal cord veins from the thyrocervical trunk.
The digital subtraction angiogram, performed after embolization, demonstrates that the abnormal veins no longer fill.
- Laminectomy and obliteration: Laminectomy is an operation in which the patient is placed on their stomach (the prone position) and an incision is made over the area of the AVM. The back of the spinal canal, called the lamina, is removed, exposing the dura, or covering of the brain and spinal cord. At this point, an AVM can be removed or an AVF can be ligated. The Neurosurgical Hybrid Operating Suite at VCU offers surgeons the ability to perform angiography during the operation to determine if all feeding arteries to an AVF have been ligated and the surgery is complete.
Moyamoya disease is a progressive disorder of blood vessel occlusion. Moyamoya usually affects the large arteries that feed the brain, including the internal carotid artery, the middle cerebral artery, and the anterior cerebral artery. For reasons that are poorly understood, these vessels occlude over time. Many small, irregularly shaped vessels sprout from these occlusions in order to perfuse the brain. On an angiogram, these vessels look like a puff of smoke. Moyamoya means puff of smoke in Japanese, where this disease is more common than in the United States.
Patient with Moyamoya can suffer from lack of adequate blood flow to the brain. A patient may experience blurred vision, paralysis, weakness, numbness, vision problems, balance or coordination problems, or speech difficulties. If these symptoms resolve quickly, the incident is called a transient ischemic attack, or TIA. If they persist, it is called an ischemic stroke. The small, irregular vessels that have developed secondary to occlusion of the larger vessels are very fragile, and a patient may suffer an intracranial hemorrhage.
Children with Moyamoya are more likely to present with signs of TIA or ischemic stroke, while adults are more likely to present with hemorrhage.
Moyamoya can be strongly suspected based on CT-angiogram or MRA, but requires digital subtraction angiography for definitive diagnosis.
The pictures below are digital subtraction angiograms that demonstrate an occlusion at the end of the internal carotid artery and small, thin, wispy vessels at the end of the carotid occlusion. These represent the �puff of smoke� for which the disease is named.
- Direct revascularization: This involves taking an artery from the scalp, usually the superficial temporal artery, or STA, and sewing it into the brain circulation, usually the middle cerebral artery, or MCA. This is abbreviated a STA-MCA bypass.
- Indirect revascularization: No all patients have an STA or MCA that are appropriate candidates for bypass. In such patients, simply laying scalp arteries or the muscle of the jaw can be laid directly on the brain. Over a period of months, the brain that is requiring more blood flow will recruit small arteries to grow from the scalp. This is called an encephaloduroarteriosynangiosis and is abbreviated EDAS.
The picture below shows a superficial temporal artery from the scalp being prepared for anastamosis, or connection, to the blood vessels of the brain.
A cavernous malformation, also referred to as a �cav-mal� is an abnormal collection of thin-walled veins. These sac-like structures contain blood, some of which may be clotted. These malformations tend to push brain tissue aside rather than involve it, as some other malformations may do. Cavernous malformations can occur in any part of the brain, spinal cord, brain stem, and optic nerve, and they can grow slowly with time.
Cavernous malformations can cause a variety of symptoms, including seizures, headache, and neurological deficits. In addition, cavernous malformations are associated with a risk of bleeding, or hemorrhage. Larger hemorrhages are serious neurological emergencies and can cause critical neurological problems.
An MRI is the most useful diagnostic test for cavernous malformations. A cavernous malformation can often have a �pop-corn� appearance because of blood of different ages. The blood within these lesions is low-flow, and therefore they cannot be seen on digital subtraction angiogram.
The MRI scan below demonstrates a cavernous malformation in the right frontal lobe. The varying degrees of white, black, and gray represent blood of different ages.
- The decision to treat a cavernous malformation depends on whether it causes symptoms and the condition of the patient. Sometimes a cavernous malformation may not require treatment and will be observed with regular MRI scans.
- Surgical resection: In cases of large or symptomatic cavernous malformations, or malformations with recurrent hemorrhages, surgery may be considered to remove the malformation. Because these abnormal vessels tend to be isolated from other structures, they usually can be removed successfully with microsurgical techniques.
- Stereotactic radiosurgery: Highly targeted radiation therapy may be indicated in rare cases in which the cavernous malformation is an area from which it cannot be safely resected. Radiation is also a possible treatment for those with symptomatic cavernous malformations who are not healthy enough for surgery.
Angioma Alliance: www.angiomaalliance.org/