PAIN Publish Ahead of Print DOI: 10.1097/j.pain.0000000000000927 Prospective Validation of the CSS 21 A Prospective, Multi-site, International Validation of the CRPS Severity Score (CSS) R. Norman Harden 1 Christian Maihofner 2 Elias Abousaad 1 Jean-Jacques Vatine 3 Amy Kirsling 1 Roberto S.G.M. Perez 4 Maxine Kuroda 1 Florian Brunner 5 Michael Stanton- Hicks 6 Johan Marinus 7 Jacobus J. van Hilten 7 Sean Mackey 8 Frank Birklein 9 Tanja Schlereth 9 Angela Mailis-Gagnon 10 Joe Graciosa 1 Sara B. Connoly 1 David Dayanim 1 Michael Massey 1 Hadas Frank 3 Anatoly Livshitz 3 Stephen Bruehl 11 1 Rehabilitation Institute of Chicago, Chicago, IL, USA 2 University of Erlangen-Nuremberg, Erlangen, Germany 3 Reuth Rehabilitation hospital, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel ACCEPTED Copyright Ó 2017 by the International Association for the Study of Pain. Unauthorized reproduction of this article is prohibited.