Cerebral Vascular Procedures
Diseases of the cerebrovascular system affect hundreds of thousands of people each year and are the third leading cause of death in the United States. Recently, major therapeutic and technological advances in the management of stroke and intracranial aneurysms and arteriovenous malformations have become available, radically altering the devastating natural progression of these conditions. Diagnosis and management, however, demand that a comprehensive, interdisciplinary team approach be available for optimum outcomes. To this end, neuroscientists at University of Pittsburgh Medical Center (UPMC), in the areas of surgical management of neurology, neurosurgery, neuroradiology and rehabilitative medicine have pooled their resources to provide one of the most comprehensive centers for the management of cerebrovascular disease in the country.
Neurosurgeons at UPMC are expert in cerebrovascular surgery and work with both extracranial and intracranial cerebrovascular disease. Below are examples of some of the disease- types treated and the different surgical approaches.
One of the leading causes of stroke is the constriction of blood flow through the carotid artery to the brain. This constriction usually occurs as a result of a buildup of plaque within the artery's walls. In addition, a piece of plaque may break away from the artery wall and travel into a narrower vessel, also resulting in a stroke. Microsurgical carotid endarterectomy is a procedure in which plaque material is removed from inside the carotid artery. The average length of stay for these patients is one to two days.
Carotid endarterectomy procedure:
Through this procedure, an incision is made into the neck's carotid artery the major
vessel bringing blood to the brain. The fatty deposits, which block blood flow to the
brain, are removed from the artery.
Figures below illustrate the process of making an incision to expose and clean out the
neck vessel that can be the cause of stroke.
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Carotid endarterectomy helps reduce stroke risk in carefully selected patients who
experience TIAs or have significant narrowing of the carotid artery.
The latest endovascular techniques are available for the treatment of aneurysms, AVM's and carotid artery disease using non-surgical methods. The embolization of aneurysms and AVM's has been done using special catheters inside the vessels of the brain and thus avoiding an open surgical procedure. Carotid artery narrowing cause by atherosclerotic can be treated with stents that can be open with the artery. Stenting and other endovascular techniques can be used for a variety of carotid and cerebral vascular lesions.
Patients who may need carotid artery surgery to remove blockages may undergo a
minimally Invasive Procedure called stent-supported angioplasty. This procedure is used to
open the carotid artery and keep it open. A small balloon is inserted in the artery and
expanded to break through the fatty deposits blocking the blood flow. Expandable metal
devices called stents are then placed in the artery and help the artery remain open.
Stent-supported angioplasty is new and considered experimental. Although at the time of
this brochure's printing, long-term outcome studies have not been done, the results look
promising, and the procedure most likely reduces the risk of having a stroke.
New treatment options
Traditionally there have been limited treatment options available once you experience a
stroke. There are, however, new procedures that are resulting in optimum recovery for
stroke patients. These new treatments require rapid and accurate diagnosis of the cause of
stroke and the location of its origin in the brain.
Intravenous thrombolysis
This treatment involves a clot-busting medication that is given intravenously. Under
certain circumstances and, if given rapidly after a stroke, it may prevent further damage.
This may be given alone or in combination with intra-arterial thrombolysis.
Intra-arterial thrombolysis
One such treatment is placement of a microcatheter into the blood vessel to deliver clot-busting medications. This often opens the blood vessel effectively and can lead to complete recovery.
The catheter is inserted into the thigh and guided to the carotid artery, the site of the clot. A microcatheter is placed within the clot obstructing the cerebral vessel. Thrombolytic, or clot-busting, agents are delivered to open the vessel.
The procedure - similar to catheterization of the heart - uses recent
advances in catheter technology, including the development of tiny microcatheters. This
treatment must be performed within six hours of the onset of symptoms.
Aneurysm and AVM Surgical Approaches
Photo of a clipped aneurysm
This surgery is performed for diseases in the anterior skull base such as tumors, paranasal sinus diseases and trauma, and is often used to treat lesions that affect the optic nerves.
This approach is used to remove lesions affecting the auditory nerves. During surgery, special monitoring constantly evaluates the function of the cranial nerves. This monitoring is designed to decrease the risk of injury to the nerves during surgery and, therefore, preserve hearing.
ELITE stands for Extreme Lateral Inferior Transcondylar Exposure. This particular operation is performed for tumors and aneurysms at the bottom-most portion of the skull at the area where the neck meets the head. The surgeon approaches from the side of the skull to reach the front of the brain stem, thus avoiding the need to elevate the brain and risk injury to brain tissue.
Platinum Micro-Coils a
New Treatment for Aneurysms
Micro-coil is a soft, platinum coil that is attached to a stainless steel delivery
wire. The softness of platinum allows the coil to conform to the often irregular shape of
intracranial aneurysms. The coil is used to occlude the aneurysmal sac.
Targeting the Disease Site Directly
To deliver these coils, a specially designed Tracker™ micro-catheter is carefully guided into the aneurysm. The delivery wire /coil combination is then threaded through the micro-catheter and deployed into the aneurysm. (figure 1)
When the coil is properly positioned it is separated from the delivery wire and releasing
the coil inside the aneurysm. (figure 2)
Once the aneurysm is occluded, the Tracker™ micro-catheter is slowly withdrawn. (figure 3)
A follow-up benchmark angiogram is performed immediately to assess the effect of the
procedure, and subsequent angiogram are performed as required.
Photo
of coiled aneurysm, note coils visible inside.
Cavernous
malformations An under appreciated cause of hemorrhagic stroke
Cerebral cavernous malformations (CCMS) are a common type of brain vascular malformation occurring in approximately 0.5 percent of the general population. In certain individuals, there is a genetic predisposition toward developing CCMs. This familial variety generally follows an autosomal dominant mode of inheritance and is often characterized by multiple lesions. Sporadic (nonfamilial) CCMs are usually solitary and are occasionally associated with other types of brain vascular malformations (particularly venous malformations).
Histologically, CCMs are sinusoidal vascular spaces lined with endothelium and an adventitial layer; they are devoid of a medial layer. There is no functional neural tissue in the intervening regions between vascular channels. Grossly, CCMs look like raspberries or mulberries embedded in the brain parenchyma. They typically have a gliotic, hemosiderin-laden margin or plane around them, the result of prior hemorrhagic oozing. This gives CCMs their classic appearance on magnetic resonance imaging (MRI), which is the best imaging modality to make an accurate diagnosis.
Because CCMs are low-flow lesions, they are almost invariably angiographically occult. Thus, cerebral arteriography provides little helpful information if a diagnosis has been capably rendered on the basis of MRI. The only exception to this rule is if one is concerned about mixed pathology, such as an associated venous malformation or arteriovenous malformation.
CCMs are often asymptomatic and may be discovered incidentally, on brain imaging done for unrelated reasons. CCMs become symptomatic when there is overt hemorrhage or intralesional bleeding that results in headache, seizure or focal neurologic deficit (due to local mass effect).
Newly discovered CCMS, particularly those that are symptomatic, warrant neurosurgical consultation. While many patients with CCMs can be managed nonsurgically, with close clinical and radiographic follow-up, others are best treated with surgical extirpation of the offending lesion. Definitive and complete resection is curative. There currently is little to no good scientific evidence that standard radiation therapy or focused radiosurgery (e.g. gamma knife) is effective treatment for CCMS.
Because of their frequency in the general population, CCMs ought to be suspected in any individual who presents with hemorrhagic stroke of unknown etiology. An accurate and timely diagnosis can mean the difference between effective (often curative) treatment and avoidable recurrent hemorrhage.
References
1. Robinson JR et al. Natural history of the cavernous angioma. J Neurosurg 75:709-14, 1991.
2. Maraire JN and Awad IA. Intracranial cavernous malformations: lesion behavior and management strategies. Neurosurgery 3 7:591-605, 1995.
3. Gunel M et al. A founder mutation as a cause of cerebral cavernous malformation in Hispanic Americans. N Eng J Med334:946-51,1996.
4. Gunel M et al. Genetic heterogeneity of inherited cerebral cavemous malformation. Neurosurgery 38:1265-71, 1996.
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Last Updated: January 1, 2008