Interventional Neuroradiology
Catheter based techniques for treating abnormalities of blood vessels are not limited to treating the blood supply to the heart. Advances in micro-engineering techniques and materials technology has led to rapid progress in the minimally invasive treatment of many conditions of not only the cardiovascular system but in most organ systems in the body. Nowhere is this more apparent than in its use in the treatment of abnormalities of the blood supply to the brain, spinal cord and the head and neck structures. This sub-specialty in medicine is known as interventional neuroradiology or endovascular neurosurgery or surgical neuroangiography.
Conditions that can be treated via these techniques include brain aneurysms, arteriovenous malformations (AVMs), carotid-cavernous fistulas, certain head and neck tumours, intracranial atherosclerosis, certain spinal vascular malformations and vertebral body compression fractures to name a few.
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Brain Aneurysm Treatment
By far the most common intervention is the management of ruptured brain aneurysms.
An aneurysm is defined as a localized weakening in the wall of a blood vessel causing the affected area of the vessel to bulge outwards under the pressure of the blood flowing within it. The bulging of the vessel wall is a very serious condition since there is a risk that the weakened vessel wall may rupture leading to severe internal bleeding, possible coma and sudden death.
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The procedure for coiling an aneurysm is similar to that of coronary intervention. In short, a plastic tube called a guiding catheter is inserted into a blood vessel in the patient’s leg via a small puncture in the skin. This catheter is then guided using X-ray images up to the blood supply to the brain. Once in place, micro-catheters and micro-guidewires are passed through the guiding catheter and carefully directed to the aneurysm.
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This technique uses soft platinum coils, similar in configuration to those old “slinky” toys, which are directly implanted into the aneurysm itself via the micro-catheter that has been inserted into the aneurysm. Sometimes balloons and stents have to be used to help keep the coils in place in the aneurysm depending on the shape of the opening or neck of the aneurysm. Usually several coils of various sizes are implanted in order to fill the aneurismal space as completely as possible. Blood that stagnates within the coil ‘mesh’ will clot, filling the aneurysm space as much as possible. This prevents further blood from entering the aneurysm, thereby protecting the bleeding point. Preventing re-bleeding is critical to good patient outcomes as it increases the likelihood of returning to as normal a lifestyle as possible.
This procedure is performed by a specially trained doctor called an interventional neuroradiologist.
When an aneurysm ruptures this is a medical emergency and usually must be treated as soon as possible.
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Prior to the advent of modern interventional neuroradiolgy techniqiues, the only treatment for this condition was sometimes complicated open brain surgery to apply a clip to the bulging blood vessel to prevent it from bleeding again.
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A more modern technique called aneurysm coiling has now become the established first line treatment for brain aneurysms once it is available.