McCarthy, K F
McCrory, C
Article History
Received: 11 September 2013
Revised: 16 April 2014
Accepted: 26 April 2014
First Online: 1 August 2014
Competing interests
: Dr McCarthy has no potential conflict of interest to declare. Dr McCrory has received research grant support from Medtronic Inc. Neither author has a commercial interest in the material presented in this article.