Primary outcomes
The primary outcome was defined as the level of abdominal pain felt with
change of position (according to the VAS scale) at 8 hours after
surgery. Based on previous studies 3,17, it was
estimated that each intervention (administration of SC and/or IP
analgesia) would result in a 20% reduction in the primary outcome, as
compared to non-intervention (administration of SC or IP placebo). In
order to attain a power of 80% and a significance level of 0.05, the
total sample size required was calculated to be 25 patients for each
group. We included 30 patients in each group, in order to make up for
any potential loss of follow up.