“…In total, 20 studies were excluded for the following reasons: the absence of or uncertainty about randomization [ 41 – 45 ], lack of reporting or uncertainty about timing [ 41 , 46 – 50 ], lack of reporting or uncertainty about diagnostic criteria for acute cholecystitis [ 41 , 45 , 46 , 51 – 54 ], limitation of the population study to the first episode and inclusion of biliary colic cases [ 53 ], inclusion of only patients with symptoms persisting for more than 72 h [ 50 ], exclusion of elderly patients [ 54 ], lack of reporting post-operative complications or lack of specifying whether the reported complications were primarily post-operative [ 16 , 41 , 48 , 49 , 55 – 58 ], or because the repoting of interim results of a randomized study [ 59 ].…”