. 2019 Dec 6;4(6):e779. doi: 10.1097/PR9.0000000000000779
Copyright © 2019 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 Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Figure 1.
PRISMA flow diagram.