brain-controlled bionic legs

I just realized that I hadn't ever really written about two hot trends in health care: bionics and 3D printing.  I better get to it before they become mainstream, or are superseded by something even newer. Let start with bionics.  According to Merriam-Webster, bionic means "having normal biological capability or performance enhanced by or as if by electronic or electromechancial devices."  Bionics is the science of this...Bionics is estimated to be an $8b market (2014), with a projected 13.2% CAGR that would bring it to $20.5b by 2020.   The artificial kidney market is said to account for some 60% of the market, with livers expected to be the fastest growing segment over the period.