The walls of blood vessels are specially designed to withstand the constant pressure associated with the arterial system. In some instances, however, an aneurysm (or out-pouching) may develop. The cause of this abnormality is not known.
This interruption of the normal vessel wall is frequently thin and weak and subject to bursting or leaking. When this happens, the patient may experience headache, nausea, vomiting, double vision, sensitivity to light, neck pain or stiffness, weakness, paralysis, memory loss, coma or death.
An angiogram is a procedure where a radiopaque dye is injected into the arteries. It casts a white shadow on the x-ray film that represents a cast of the inside of the blood vessels. The portion of the study that examines the arteries is often referred to as an arteriogram. This is performed to determine the exact size, shape and location of the aneurysm.
Arteriogram - Lateral view showing a posterior communicating artery aneurysm.
Arteriogram showing an aneurysm on the posterior communicating artery.
Arteriogram showing clip placed across the neck of the aneurysm. The aneurysm no longer fills with blood.
MRA (Magnetic Resonance Angiography)
By applying the unique characteristics of MR, imaging techniques have been developed to allow for the visualization of blood vessels without the injection of radiopaque dye or use of x-ray. The procedure provides very good images that are often acceptable. In many cases, however, conventional angiography is required for evaluating intracranial aneurysm's since MRA does not provide the same degree clarity and accuracy.
In order to prevent the aneurysm from hemorrhaging (bleeding) or re-bleeding, the neurosurgeon places a clip across the neck of the aneurysm. This surgery is performed with the aid of a surgical microscope.
Types of Aneurysm's
The difficulty of this procedure depends upon the type of aneurysm and its location. A "saccular" aneurysm with a narrow neck is less difficult to clip than one with a broad neck. The most difficult aneurysm to manage is the "fusiform" type. Also difficult to manage is the "giant" aneurysm (2.5cm or greater).
In some instances, when it is not possible to surgically clip an aneurysm because of its location or when the patient cannot undergo a surgical procedure because of other risk factors, embolization is an option. The procedure used most commonly involves the insertion of a "coil" of wire into the aneurysm. The coil is delivered to the aneurysm through catheters (tubes) placed in the arteries. The procedure does not involve an open craniotomy and can be done under local anesthesia. Other methods of embolization include balloons and rapidly solidifying polymers. Surgical clipping remains the procedure of choice whenever it is possible because of its known effectiveness in permanently closing off the aneurysm to the flow of blood.
Blood relatives of patients with aneurysms should be evaluated by a neurosurgeon since this condition is hereditary. Early treatment can help to prevent complications.
Posted on Mon, October 13, 2014
by Greg Neundorfer