Mind what you wish for!

Cardiothoracic Surgery in the UK is, as far as the General Medical Council and the Colleges of Surgery are concerned, a single specialty.

Medical Super Specialisation is good AND bad for patients!

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  Surgeon volume and early complications after primary total hip arthroplasty | BMJ
  This is an interesting article suggesting that if a surgeon specialises in one type of operation and therefore carries out a large number of them per year, his patients are less likely to suffer complications. 
• In an age when patient outcomes are important, this strengthens the case for further specialisation in different disciplines of surgery. In my specialty, cardiac surgery for example, there are moves now for surgeons just to specialise in surgery of the mitral valve or surgery of the aorta. If I was a patient with mitral valve disease, I know who I would want to operate on my mitral valve . 
• There are however tensions and problems associated with increasing specialisation.