© 2018 by IGCS and ESGO. Reuse of this manuscript version (excluding any databases, tables, diagrams, photographs and other images or illustrative material included where another copyright owner is identified) is permitted strictly pursuant to the terms of the Creative Commons Attribution-Non Commercial 4.0 International, https://creativecommons.org/licenses/by-nc/4.0/.
Except where otherwise noted, this item's license is described as © 2018 by IGCS and ESGO. Reuse of this manuscript version (excluding any databases, tables, diagrams, photographs and other images or illustrative material included where another copyright owner is identified) is permitted strictly pursuant to the terms of the Creative Commons Attribution-Non Commercial 4.0 International, https://creativecommons.org/licenses/by-nc/4.0/.