Surgery+Steps


 * CT Angiography Guide:**

Overview: In this scene, the student performs a CT Angiograph on Mr. Jones. The purpose of this activity is to determine the exact location of Mr. Jones’ suspected aneurysm. Once located, the aneurysm can then be treated.

Steps:

Entering the Body - Special Notes:
 * 1) The student inserts an introducer needle into the patient’s femoral artery. This is done be clicking on the needle in the tool tray on the lower right hand side and dragging to the opening located around the patient’s upper thigh. In real life, this needle penetrates the skin and tissues and allows the surgeon access to the femoral artery.
 * 2) The student then inserts a guidewire into the introducer needle, which allows it to penetrate the femoral artery. As its name indicates, this wire will act as a guide for the introducer sheath to follow.
 * 3) The introducer needle is then removed and put into the biohazardous waste container as its role is now done.
 * 4) The student then threads the introducer sheath over the guidewire, providing a pathway for the wider catheter to follow.
 * 5) The main catheter is then threaded through the introducer sheath and over the guidewire to provide a pathway into the femoral artery.

If the process to enter the body and access the brain via the femoral artery seems tedious and complex, it is. In reality, this process can take several hours. The reason that so many different guidewires and catheters are needed is that the blood vessels narrow and become more fragile as one gets closer to the brain. Too narrow or flexible of a catheter in the larger blood vessels will not make sufficient progress towards the brain. Too large or rigid of a catheter can damage or rupture the smaller blood vessels.

Advancing the Guidewire -
 * 1) The student advances the guidewire from the femoral artery to the left anterior communicating artery using the control, virtual image, and artery map to assist.
 * 2) The student runs a contrast scan where dye is injected to get a better image of the bleed area.
 * 3) The student performs a Digital Subtraction Angiography to get a better image of the hemorrhaging area.
 * 4) Once that image is obtained, the student creates a 3D image of the hemorrhaging area to determine how to treat it.
 * 5) The student can now view the aneurysm causing the bleed and is asked to determine how to treat it.
 * 6) Student determines to coil the aneurysm.

Special Notes -

The control for advancing the guidewire is located on the right hand side of screen. The student can see the guidewire advance in the screen on the upper left hand side of the screen. In order to turn the guide wire right or left, the student needs to manipulate the control right or left in a twisting motion. This is similar to how the surgeon actually controls the guide wire. The right hand image is a map that students can use as a reference for cardiovascular mapping. Students need to advance the guide wire up through the left carotid artery to the left anterior communicating artery. This is a common location of aneurysms.

In real life, the surgeon does several contrast dye injections to make sure he or she knows where the guidewire is located and to keep track of the blood vessel anatomy.

Procedures such as Digital Subtraction Angiography and 3D modeling seem simple in this virtual lab but are actually quite complex in real life. They are tools that have become invaluable in the world of interventional cardiovascular and neurology surgery. The contrast dye highlights blood flow, enabling the surgeon to see the outline of the blood vessels.

The best way to treat Mr. Jones’ aneurysm is to coil it as this is the least invasive of the options. By filling the aneurysm with coils, the student will fill the aneurysm and block blood from entering. This will keep the aneurysm from bursting.

Accessing the Aneurysm:

Steps - Special Notes:
 * 1) The student inserts the microguidewire into the main catheter.
 * 2) The microcatheter is threaded over the microguidewire.
 * 3) The student guides the microguidewire and microcatheter through the arteries to the brain.
 * 4) The student inserts a variety of coils (from largest to smallest) in the aneurysm in order to fill the aneurysm. First the student must select the correct coil, advance it to the aneurysm site, and then detach it once the aneurysm is filled.
 * 5) The student removes the microcatheter.
 * 6) The student injects contrast dye to make sure the aneurysm is completely filled with coils and that blood is no longer entering the aneurysm.

Since the main catheter is still in place, it provides a pathway through the arteries to the brain. However, the brain’s blood vessels are so small that a micro system is needed to reach the aneurysm.

When coiling an aneurysm in real life, a surgeon will study the 3D image of the aneurysm in great length to determine how many coils he or she will need to use to fill the aneurysm and what size they should be. The number of coils varies based on the size of the aneurysm. Usually, as in this lab, the larger coils are inserted first with the smaller coils used to fill in gaps. In reality, these coils are spring loaded. When pushed out of their sheath, they take on their preformed shape and are then detached from their wire. That wire is then removed from the body.

The final scan doesn’t show an aneurysm because the contrast dye shows blood flow. Since the aneurysm is completely coiled, no blood can enter the aneurysm, which is why it no longer shows up on the scan.