Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The International Association for the Study of Pain.
This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike License 4.0 (CC BY-NC-SA) which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.