Date	Event	Description
19 January 2015	New citation required but conclusions have not changed	In this update, the review authors have added 13 new trials (Ahmed 2012; Dijkstra‐Eshuis 2013; Fader 2013; Fode 2014; Geraerts 2013; Ghanem 2013; Hou 2013; Laurienzo 2013; Marchiori 2010; Martini 2011; Morihiro 2011; Park 2012; Tienforti 2012). Risk of bias assessment was performed on all 50 trials in accordance with the current methodology. Overall, 37/50 trials were also included in the previous update (Campbell 2012) and 13/50 trials were identified in this update. Quality of evidence was assessed by adopting the GRADE approach.
19 January 2015	New search has been performed	In this update, the review authors have added 13 new trials (Ahmed 2012; Dijkstra‐Eshuis 2013; Fader 2013; Fode 2014; Geraerts 2013; Ghanem 2013; Hou 2013; Laurienzo 2013; Marchiori 2010; Martini 2011; Morihiro 2011; Park 2012; Tienforti 2012). Risk of bias assessment was performed on all 50 trials in accordance with the current methodology. Overall, 37/50 trials were also included in the previous update (Campbell 2012) and 13/50 trials were identified in this update. Quality of evidence was assessed by adopting the GRADE approach.
24 August 2011	New search has been performed	18 new trials added
24 August 2011	New citation required and conclusions have changed	In this update, 18 new trials have been added (of which 1 was a previously excluded trial). The total number of trials included is now 37.
16 September 2008	Amended	Converted to new review format.
21 February 2007	New citation required and conclusions have changed	Substantive amendment. In this update (Issue 2 2007), 7 trials were added to the review. The total number of studies included was 17. In this update, comparisons were separated on the basis of type of surgery and as well whether the intervention occurred pre‐ or post‐operatively.
25 February 2004	New citation required and conclusions have changed	Substantive update Issue 2 2004. In this update, five trials were added to the review. One trial previously listed as included was excluded after attempts to contact the author to access data were unsuccessful. The total number of studies included was 10. 7 extra studies were excluded.
23 January 2001	New citation required and conclusions have changed	Substantive update Issue 2 2001