An aneurysm is a localized, balloon-like expansion in a blood vessel caused by weak vessel walls. In most cases, aneurysms cause no symptoms and are often found while patients are being treated for another medical condition. However, there are cases where an aneurysm may elicit a sudden, severe pain. As the aneurysm enlarges, the chance it will rupture increases; complications from the sudden breaking of an aneurysm are considered a medical emergency and can lead to sudden death.
Types and Causes of an Aneurysm
There are several traits of an aneurysm to observe and consider when approaching surgical treatment.
First, the aneurysm may be true or false.
A true aneurysm results in the characteristic bulge of inner circulatory tissue being exposed through the outer tissue.
A false aneurysm is actually a slow leak in the vessel wall that pools up just beside the artery due to the surrounding tissue tightly encapsulating it.
The location of an aneurysm is also important. Most non-cranial aneurysms are located on the aorta, the main artery leaving the heart. Major blood vessels may be affected by an aneurysm.
Diagnosis of an Aneurysm
Abdominal aortic aneurysms may be detected by manual examination by a physician, X-rays, ultrasound, CT scans, MR imaging and aortography. If a ruptured aneurysm is suspected, a lumbar puncture may be ordered to determine if there is any blood mixing with the cerebrospinal fluid.
Treatment of an Aneurysm
Surgery is recommended for arteries at great risk for rupture: those over six centimeters wide, and those four to six centimeters wide in patients otherwise in good health. Surgery is performed immediately on arteries that threaten imminent rupture or have already ruptured, although a successful outcome is far less likely once the vessel has burst.
Traditional surgery involves making an incision to open the abdomen, removing the aneurysm and replacing the excised vessel piece with synthetic tubing. Recent minimally invasive laparoscopic techniques require only small incisions, typically made to the femoral artery in the thigh, through which a thin tube with a camera is inserted so the surgeon can "see" inside the patient's body without the need for open surgery.
In the laparoscopic approach, a stent graft is inserted into one of the small incisions and guided up to the weak area of the artery with a catheter. Stent grafts are six-inch-long metal-mesh cylinders containing synthetic Dacron tubes. Once inside the artery they are expanded to fill the vessel, providing a strong new vessel wall and permitting uninterrupted blood flow. The aneurysm generally shrinks around the stent graft as time passes.