If you've had an aneurysm treated by coiling you must have wondered about those coils in your head. What are they made of? How did they get there? Will they come out? Will I need more? Well I'm going to attempt to answer some of those questions here.
Firstly, My qualifications: I'm not a doctor or surgeon. Nor indeed am I a medical expert of any kind, but I suffered a brain haemorrhage in 2006 due to a ruptured aneurysm and had it treated by coiling. One of the things that concerned me when I was discharged from hospital was the lack of information about what had happened to me and how it had been treated. There are many medical articles out there on the web that deal with subarachnoid haemorrhage and coiling, but understanding the jargon can be a bit daunting, so I will try to give you the benifit of my own research and explain things in simple terms.
The number one priority following a subarachnoid haemorrhage due to a ruptured aneurysm is prevention of re-bleeding. The traditional method is to open the skull, locate the aneurysm and place a titanium clip over the neck of the aneurysm to seal it off from the circulation. The first successful clipping was carried out in 1937, but in 1991 a new method of treatment was introduced which effectively sealed off the aneurysm from the inside. This treatment is called endovascular coiling (Endo = inside, vascular = relating to the blood vessels). Coiling has the advantage that it does not require invasive surgery and can improve recovery times. Not all aneurysms are suitable for coiling and therefore clipping is still in common use and is arguably more permanent.
The idea of endovascular treatment is to pack the inside of aneurysm with some kind of material to seal it off from the parent artery. Coiling consists of filling the aneurysm with fine wires which coil up inside to the shape of the aneurysm. These wires are called GDC - Guglielmi Detatchable Coils, named after their inventor.
What are the coils made from?
The coils are fine platinum wires about twice the thickness of a human hair. They are available in many different lengths and types.
How are they inserted?
The operation is carried out under a general anaesthetic by a neuroradiologist in a special operating theatre. Firstly, a plastic tube called a catheter is inserted into an artery in the groin and is navigated through the arteries to the brain using x-ray guidance. A contrast agent is injected into the catheter to map the arteries so they show up clearly on the x-ray screen. This part of the procedure is similar to a cerebral angiogram.
A smaller plastic tube called a micro-catheter is guided through the first catheter until it's tip is inside the aneurysm. A coil attached to a stainless steel delivery wire is fed through the micro-catheter and into the aneurysm. The coil is very soft, so as it exits the micro-catheter, it coils up inside the aneurysm. When the coil is fully deployed and the neuroradiologist is happy with the placement, a small electric current is passed through the delivery wire which detatches the coil from the end. The delivery wire is then withdrawn. Most aneurysms require more than one coil (I have four), so the procedure is repeated until the aneurysm is completely packed with coils. A final angiogram is done to make sure everything is OK and then both catheters are withdrawn.
That's it - job done! You're now fixed up ready to start your recovery.
Will they come out and will I need more coils?
It is very rare that the coils come out once inserted, but the coils can sometimes compact over time. This is usually detected during routine follow-up imaging and it may occasionally be necessary to insert more coils.