Bailey 2008

Methods	Single centre, RCT. Enrolment period: August 2003 to April 2006. Endoscopist(s): two experienced endoscopists supervised procedures performed by a dedicated ERCP training fellow. The fellow commenced the procedure in the majority of cases (77.5%).
Participants	Country: Australia. 430 patients with an intact papilla who were referred for ERCP.
Interventions	1. Guidewire‐assisted cannulation: a hydrophilic tipped 0.035 inch guidewire (Jagwire, Boston Scientific) through a sphincterotome (Olympus). Guidewire was used to access the CBD, followed by cannulation and opacification. Guidewire was advanced by an assistant. 2. Contrast‐assisted cannulation: standard method of cannulation through a sphincterotome (Olympus).
Outcomes	PEP; cannulation success; time to successful cannulation; the number of cannulation attempts; the number of inadvertent PD cannulations or injections; independent predictors of PEP and adjusted odds ratios from multiple logistic regression.
Notes	1. Defined PEP according to the consensus definition (Cotton 1991). 2. Graded severity of PEP based on the consensus criteria (Cotton 1991). 3. 'Cross‐over' technique: The fellow attempted initially for five minutes. If unsuccessful, the consultant attempted for 5 minutes using the same technique, followed by 'cross‐over' to the other technique in the same sequence. Did not report PEP data for those with and without 'cross‐over' separately. Authors contacted: in the guidewire‐assisted group, total PEP = 16 (13 mild, 3 moderate) with 6 crossed over to contrast (5 mild, 1 moderate) and 10 did not crossover (8 mild, 2 moderate). In the contrast‐assisted group, total PEP = 13 (9 mild, 4 moderate) with 6 crossed over to guidewire (3 mild, 3 moderate) and 7 did not cross over (6 mild, 1 moderate). 4. Precut was permitted. If attempts at cannulation failed, a needle‐knife sphincterotomy (NKS) was performed by the consultant endoscopist where appropriate. The consultant could proceed directly to NKS without 'cross‐over' if it seemed that the alternate technique was likely to fail. 5. PD stents were used at the discretion of the endoscopists. 6. Did not report on the number of patients with inadvertent PD injection / cannulations. Authors contacted: in the guidewire‐assisted group, 67 had one or more inadvertent PD injection / cannulation and 119 had no PD injection / cannulation. In the contrast‐assisted group, 104 had one or more inadvertent PD injection / cannulation and 94 had no PD injection / cannulation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"randomised using a computer‐generated randomisation program".
Allocation concealment (selection bias)	Unclear risk	No information was provided.
Blinding of participants and personnel (performance bias) All outcomes	High risk	No information was provided. Endoscopists could not be blinded. "The proceduralist was informed of which treatment had been assigned immediately after commencement of the procedure."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information was provided. "All patients were assessed clinically at the bedside before discharge from the endoscopy unit"; "All patients were asked to have serum collected for amylase and lipase levels the day after ERCP"; and "Telephone interviews were performed by the endoscopy fellow on day 1 and day 30 after ERCP".
Incomplete outcome data (attrition bias) All outcomes	Low risk	No patients were lost to follow‐up. Excluded 17 randomised patients (13 vs. 4) from the final analysis, primarily because of the presence of unsuspected prior sphincterotomy or surgically altered anatomy. ITT sample was used in our analysis.
Selective reporting (reporting bias)	Low risk	Reported all planned outcomes.
Other bias	Low risk	No other risk of bias.