Abstract: We included seven RCTs comprising 577 participants. There was no significant heterogeneity among trials for the outcome of PEP (P = 0.32; I2 = 15%). The PGW technique significantly increased PEP compared to other endoscopic techniques (RR 1.98, 95% CI 1.14 to 3.42; low-quality evidence). The number needed to treat for an additional harmful outcome was 13 (95% CI 5 to 89). Among the three studies that compared the PGW technique with persistent CC, the incidence of PEP was 13.5% for the PGW technique and 8.7% for persistent CC (RR 1.58, 95% CI 0.83 to 3.01; low-quality evidence). Among the two studies that compared the PGW technique with precut sphincterotomy, the incidence of PEP was 29.8% in the PGW group versus 10.3% in the precut group (RR 2.92, 95% CI 1.24 to 6.88; low-quality evidence). Among the two studies that compared the PGW technique with PD stent placement, the incidence of PEP was 11.7% for the PGW technique and 5.0% for PD stent placement (RR 1.75, 95% CI 0.08 to 37.50; very low-quality evidence). There was no significant difference in common bile duct (CBD) cannulation success with the randomised technique (RR 1.04, 95% CI 0.87 to 1.24; low-quality evidence) or overall CBD cannulation success (RR 1.04, 95% CI 0.91 to 1.18; low-quality evidence) between the PGW technique and other endoscopic techniques. There was also no statistically significant difference in the risk of other ERCP-related complications (bleeding, perforation, cholangitis, and mortality). The results were robust in sensitivity analyses. The overall quality of evidence for the outcome of PEP was low or very low because of study limitations and imprecision. In people with difficult CBD cannulation, sole use of the PGW technique appears to be associated with an increased risk of PEP. Prophylactic PD stenting after use of the PGW technique may reduce the risk of PEP. However, the PGW technique is not superior to persistent attempts with CC, precut sphincterotomy, or PD stent in achieving CBD cannulation. The influence of co-intervention in the form of rectal peri-procedural nonsteroidal anti-inflammatory drug administration is unclear.

Plain-language summary: We conducted a search of the literature on 15 April 2016. We identified seven randomised controlled trials conducted in China, Japan, South Korea, Spain, Thailand, and the United States including a total of 577 participants. These trials compared the PGW technique versus persistent use of traditional techniques or other advanced techniques in people undergoing ERCP in whom access to the bile duct using traditional techniques was considered by the endoscopists to be difficult. As in clinical practice, the criteria used to define difficult access to the bile duct were highly variable among studies. We assessed outcomes of post-ERCP pancreatitis (PEP), success rates in accessing the bile duct, and other post-ERCP complications (bleeding, infection, hole in the bowel wall, death). Contrary to popular belief, the PGW technique appears to increase the risk of PEP and does not improve the success rate of gaining access to the bile duct compared to other endoscopic techniques. The technique may increase the risk of mild PEP, but not moderate or severe PEP. There was no significant difference in success rates for accessing the bile duct. The risks for other complications such as bleeding, hole in the bowel wall, inflammation of the bile duct, and death appear to be low. Overall, we considered the quality of evidence for the outcome of PEP to be low. We considered none of the included studies to be at low risk of bias for all criteria. In most of the studies, both the participants and the medical staff were aware of which method was being used, therefore their judgments may not have been objective and the results should be interpreted cautiously.