Fig. 5
![Fig. 5](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12894-017-0239-x/MediaObjects/12894_2017_239_Fig5_HTML.gif)
Funnel plots of each variable. a Operation time, b visual analogue scale (VAS) pain score, c hemoglobin change, d length of stay, and e transfusion rate. For operation time, hemoglobin change, and transfusion rate, little evidence of publication bias was demonstrated on visual or statistical examination of the funnel plots; however, for VAS scores and hospital stay, moderate evidence of publication bias was demonstrated on visual or statistical examination of the plots