Abstract: We included six trials with 520 patients comparing pre-operative biliary drainage (265 patients) versus no pre-operative biliary drainage (255 patients). Four trials used percutaneous transhepatic biliary drainage and two trials used endoscopic sphincterotomy and stenting as the method of pre-operative biliary drainage. The risk of bias was high in all trials. The proportion of patients with malignant obstruction varied between 60% and 100%. There was no significant difference in mortality (40/265, weighted proportion 14.9%) in the pre-operative biliary drainage group versus the direct surgery group (34/255, 13.3%) (RR 1.12; 95% CI 0.73 to 1.71; P = 0.60). The overall serious morbidity was higher in the pre-operative biliary drainage group (60 per 100 patients in the pre-operative biliary drainage group versus 26 per 100 patients in the direct surgery group) (RaR 1.66; 95% CI 1.28 to 2.16; P = 0.0002). The proportion of patients who developed serious morbidity was significantly higher in the pre-operative biliary drainage group (75/102, 73.5%) in the pre-operative biliary drainage group versus the direct surgery group (37/94, 37.4%) (P < 0.001). Quality of life was not reported in any of the trials. There was no significant difference in the length of hospital stay (2 trials, 271 patients; MD 4.87 days; 95% CI -1.28 to 11.02; P = 0.12) between the two groups. Trial sequential analysis showed that for mortality only a small proportion of the required information size had been obtained. There seemed to be no significant differences in the subgroup of trials assessing percutaneous compared to endoscopic drainage. There is currently not sufficient evidence to support or refute routine pre-operative biliary drainage for patients with obstructive jaundice. Pre-operative biliary drainage may increase the rate of serious adverse events. So, the safety of routine pre-operative biliary drainage has not been established. Pre-operative biliary drainage should not be used in patients undergoing surgery for obstructive jaundice outside randomised clinical trials.

Plain-language summary: We included six trials involving 510 patients for this review. The number of patients included in the trials varied from 40 to 202. All trials had a high risk of bias, that is, the trials may overestimate benefits and underestimate harms. There was no significant difference in risk of death between the two groups. The rate of serious complications was higher in the patients who underwent biliary drainage prior to operation compared with those who underwent surgery directly. The quality of life was not reported in any trial. There was no significant difference in the length of hospital stay between the two groups. The costs were not reported in any of the trials. Based on the currently available best evidence, there is no justification for the use of routine drainage of bile before a major operation in patients with obstruction to the flow of bile. Routine biliary drainage should not be funded and may result in litigations. Furthermore, well designed trials with low risk of systematic errors and low risk of random errors (low risk of play of chance) may be necessary.