Sciencealert:  Brain aneurysms are the stuff of nightmares – a blood vessel in your brain which silently bulges or balloons, with the risk of it one day rupturing, causing life-threatening complications.
 Although there are a number of treatments for brain aneurysms, you can imagine that blood vessels in the brain can be a little tricky to reach. So, for the purposes of evaluating treatments and giving doctors some hands-on training time, some kind of substitute before they get inside your brain would be ideal.  A team of researchers based in the US has now brought such a thing into reality. They produced the first living, bio-printed aneurysm outside the human body, conducted a medical procedure on it, and then observed it healing.
 If doctors notice that someone has a brain aneurysm before it ruptures – unfortunately they’re hard to spot so this doesn’t always happen – they’ll attempt to stop blood flow to the area. There are a couple of different ways to treat it, and none of the options are particularly fun.  The first option is surgical clipping – where a surgeon removes part of your skull and puts a tiny metal clip on the base of the aneurysm.
 The other option is something called endovascular coiling, where a catheter is inserted into an artery in the groin, and then threaded through the body to the aneurysm. A coil is then pushed through the catheter and into the aneurysm.
Both treatments stop or disrupt blood flow, which means the aneurysm won’t get any larger and potentially burst. But both methods also present their own issues, and it can be hard to pick which option is the best for any given patient.