Klempa 1995.

Methods	Randomised controlled trial
Participants	Country: Germany Number randomised: 43 Post‐randomisation drop‐outs: not stated Revised sample size: 43 Mean age (years): 47 years Women: 10 (23.3%) Follow‐up period (years): range 3‐5.5 years (mean not reported) Number of study centres: 1 Inclusion criteria Ongoing chronic obstructive pancreatitis for multiple (3‐12) years with pain requiring analgesia or with severe pain as judged by independent investigators in a repeated manner (second opinion) Complications such as choledochostenosis causing jaundice, duodenal stenosis with stomach emptying disorders, compression of the duct of Wirsung in the head part of the organ, multiple pseudoaneurysm of the pancreatic head, transverse colon stenosis, segmental portal hypertension with compression of the superior mesenteric vein
Interventions	Participants were randomly assigned to 1 of 2 groups Group 1: duodenum‐preserving pancreatoduodenectomy (n = 22) Further details: Beger procedure Group 2: pancreatoduodenectomy (n = 21) Further details: Whipple procedure
Outcomes	Mortality, post‐operative complications, length of hospital stay, proportion of people employed, diabetes, and exocrine insufficiency
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "the patients according to the random number list (created prior to the study) were classified into two groups"
Allocation concealment (selection bias)	Unclear risk	Comment: this information was not available
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	Unclear risk	Comment: this information was not available
Selective reporting (reporting bias)	Low risk	Comment: all important outcomes were reported
Other bias	Unclear risk	Comment: it was not clear whether participants were excluded because of malignancy

CT: computed tomography; DPPHR: duodenum‐preserving pancreatic head resection; n: number of participants; PPPD: pylorus‐preserving pancreaticoduodenectomy.