At least in criminal law there is the concept of "necessity". That is, an illegal activity may in certain cases be legal, if it is necessary to prevent serious

At least in criminal law there is the concept of "necessity". That is, an illegal activity may in certain cases be legal, if it is necessary to prevent serious harm. Since the manufacturer was unable to supply the part, I would argue that 3D printing it was most certainly a "necessity", at least until either patients stop requiring it, or more parts can be procured. There are some civil law analogs such as being able to trespass someone else's property in emergency situations.