Fig. 6

Trial-sequential analysis of 12 trials comparing FIB with control for postoperative pain at 24 h. The blue line represents the summary of what has been found after each trial, the Z score resulting from the cumulative evidence. The curved red lines are the TSA monitoring boundaries, for benefit (on the top of the graph), harm (on the bottom of the graph), and futility (the inner wedge). The horizontal red lines represent conventional model boundary of p < 0.05. The RIS is the required information size, which is an estimate of the number of participants required to answer the defined question. FIB, fascia iliaca block; RIS, required information size; TSA, trial-sequential analysis