Keck 2012.

Methods	Randomised controlled trial
Participants	Country: Germany Number randomised: 92 Post‐randomisation drop‐outs: 7 (7.6%) Revised sample size: 85 Mean age (years): 42 Women: 13 (15.3%) Follow‐up period (years): 3.5 Number of study centres: 1 Inclusion criteria Radiological signs of chronic pancreatitis (inflammatory head mass, calcifications, duct abnormalities) Severe recurrent pain attacks Complications involving adjacent organs (e.g. biliary duodenal stenosis or pseudocysts) Exclusion criteria Presence of complications not allowing PPPD and DPPHR. e.g. stenosis of distal stomach, suspicion of or generalised portal hypertension
Interventions	Participants were randomly assigned to 1 of 2 groups Group 1: duodenum‐preserving pancreatoduodenectomy (n = 42) Further details: Beger or Frey procedure Group 2: pancreatoduodenectomy (n = 43) Further details: PPPD
Outcomes	Mortality, post‐operative complications, quality of life, length of hospital stay, proportion of people employed, diabetes, and exocrine insufficiency
Notes	Reasons for post‐randomisation drop‐outs: 2 participants in PPPD group underwent classic Whipple procedure and 3 participants in the DPPHR group underwent PPPD; 2 participants were lost to follow‐up
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: this information was not available
Allocation concealment (selection bias)	Low risk	Quote: "Randomization was performed before the operation via coded cards in sealed envelopes"
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: information on participant blinding was not available. It is impossible to blind surgeons who perform the procedure
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: this information was not available
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: 2 participants were lost to follow‐up
Selective reporting (reporting bias)	Low risk	Comment: all important outcomes were reported
Other bias	High risk	Comment: participants were excluded because they did not receive the planned operation. The reasons for this were: 2 participants in the PPPD group under classic Whipple procedure owing to severe inflammatory involvement of the distal stomach and 3 participants in the DPPHR group underwent PPPD because of suspicion of malignancy