Date	Event	Description
6 May 2015	New search has been performed	This review has been transferred to the Anaesthesia, Critical and Emergency Care Group by the Bone, Joint and Muscle Group
17 February 2009	New search has been performed	For the second substantive update (Issue 2, 2009), we made the following changes. 1. We included the following newly identified studies: Cuvillon 2007, Fletcher 2003, Foss 2005, Foss 2007, Gille 2006, Kullenberg 2004, Matot 2003, Murgue 2006 and Tuncer 2003. 2. We excluded the following studies: Gorodetskyi 2007, Mannion 2005, Marhofer 1998, Mutty 2007, Schiferer 2007, Turker 2003 and Piangatelli 2004. We made no changes to the conclusions of the review
6 November 2008	Amended	We converted the review to new review format
21 November 2001	New citation required and conclusions have changed	In this substantive update (Issue 1, 2002), we included one newly identified study (Scheinin 2000). We made no changes to the conclusions of the review For details on all updates, please see 'Notes'