Medical and biotechnology has advanced at an impressive rate over recent years and the latest development of a microscopic catheter looks set to allow for more delicate and deep brain surgery than possible until now. Swiss scientists, who recently published their findings in the journal Nature Communications, have developed an ultra-fine wire catheter finer than a human hair. The device is so fine that the body’s natural blood flow carries it into previously inaccessible parts of the brain.
The hope is that the new device will allow surgeons to tackle brain tumours and potentially other issues, in regions of the brain that couldn’t previously be reached. Until now, tumours in the brain have been targeted with a very thin wire inserted into arteries in the vicinity of the leg or groin. The wire is then guided up to blood vessels in and around the brain with the help of a fluoroscope, which uses x-rays to visualise the blood vessels it is moved along. A surgeon manually moves the wire into damaged brain vessels before a catheter is threaded up the wire and used to deliver drugs of devices to the damaged area.
While a major advance on previous options, the wires used in brain surgery today still have their shortcomings. Especially peripheral brain vessels are often inaccessible to the wire as they are too narrow and intricate. And there are risks. If the wire is too stiff, blood vessels can be pierced causing tissue damage. Not stiff enough and there is a danger of it getting stuck. So, surgeons have been limited to using the technique for only the areas of the brain the wire can safely reach.
The new ultra-fine, and flexible wire developed by Swiss scientists from the École Polytechnique Fédérale de Lausanne in Switzerland solves many of those problems. With a thickness of just 100 microns, it is moved through capillaries by the flow of blood. A magnetic head allows for some additional guidance from a surgeon able to work from outside the patient’s body. Being carried along by the blood flow reduces the risk of the catheter hitting blood vessel walls.
Lucio Pancaldi-Giubbini, who led the research project, explains:
“Imagine a fish-hook gradually released into a river. It will get carried along by the current. We simply hold on to one end of the device and let the blood drag it to the most peripheral tissues.”
Source: The Times
Tests demonstrated the new wire is flexible enough to pass through capillaries without damage. Using the body’s blood flow also reduces the time needed to guide it into the right position, means operations can need just a few minutes, rather than the current several hours. Reducing the time period during which the patient remains under general anaesthetic also minimises the risk of brain surgery.
Being able to reach previously inaccessible blood vessels will mean the device should allow for the delivery of drug treatments directly into the centre of brain tumours. The device could also be used for diagnosis. The report published in Nature Communications states:
“For the first time, we showed that accessing deep brain regions through the endovascular path [inside the blood vessel] is technically feasible. Such access might open new therapeutic options to treat deep-seated or very peripheral tumours inside the brain.”
So far, the new device has only been proven in laboratory experiments and tests in the fine blood vessels in the ears of rabbits. The next stage of testing will involve using the wire to treat brain tumours on live animals.
As well as application in brain surgery, the researchers also believed their device will also be able to reach delicate, hard-to-reach blood vessels in the spine, heart and eye retina. Surgical robots will most likely be used to examine MRI and CT scans and map routes to target locations, using the magnet head and blood flow to reach them.
The past couple of years have delivered a number of breakthroughs in technology designed to reach inaccessible parts of the brain. MIT scientists last year unveiled a thread-like robot able to move through blood vessels in the brain to break up the kind of blockages that cause strokes. It was used to deliver drugs to targeted areas inside the brain during the “golden hour” of opportunity to minimise damage after a stroke.