Supplementary Fig. 2.

 Results of a cumulative meta-analysis of surgical intervention data in which studies are sorted by size (largest to smallest). The first row was a meta-analysis based on the largest study (Abbas et al., N = 59 patients). The second row was a meta-analysis based on the first two studies (Abbas et al., N = 59 patients and Navaneethan et al., N = 54 patients), and so on. The figure demonstrates that by including the six large studies, with a cumulative sample size of 261 patients, this yielded a mean for surgical intervention rate of 2.4 % (95 %CI – 0.6 % to 5.3 %). As smaller studies were added, the overall surgical intervention rate drifted slightly lower to 1.9 % (95 %CI – 0.2 % to 4.0 %). The point estimate and its confidence levels did not shift with the addition of the remaining four smaller studies suggesting that the publication bias was not significant in our study.