Abstract: We identified three eligible trials. Two trials compared endoscopic intervention with surgical intervention and included a total of 111 participants: 55 in the endoscopic group and 56 in the surgical group. Compared with the endoscopic group, the surgical group had a higher proportion of participants with pain relief, both at middle/long-term follow-up (two to five years: risk ratio (RR) 1.62, 95% confidence interval (CI) 1.22 to 2.15) and long-term follow-up (≥ five years, RR 1.56, 95% CI 1.18 to 2.05). Surgical intervention resulted in improved quality of life and improved preservation of exocrine pancreatic function at middle/long-term follow-up (two to five years), but not at long-term follow-up (≥ 5 years). No differences were found in terms of major post-interventional complications or mortality, although the number of participants did not allow for this to be reliably evaluated. One trial, including 32 participants, compared surgical intervention with conservative treatment: 17 in the surgical group and 15 in the conservative group. The trial showed that surgical intervention resulted in a higher percentage of participants with pain relief and better preservation of pancreatic function. The trial had methodological limitations, and the number of participants was relatively small. For patients with obstructive chronic pancreatitis and dilated pancreatic duct, this review shows that surgery is superior to endoscopy in terms of pain relief. Morbidity and mortality seem not to differ between the two intervention modalities, but the small trials identified do not provide sufficient power to detect the small differences expected in this outcome. Regarding the comparison of surgical intervention versus conservative treatment, this review has shown that surgical intervention in an early stage of chronic pancreatitis is a promising approach in terms of pain relief and pancreatic function. Other trials need to confirm these results because of the methodological limitations and limited number of participants assessed in the present evidence.

Plain-language summary: We performed a search in March 2014 and found three relevant randomised trials. Two comparing endoscopic versus surgical interventions (111 patients with durations of two and three years), while the third compared surgery to conservative treatment (i.e. no intervention) (32 patients with a duration of 16 months). We found that surgery achieved pain relief in a higher proportion of participants than endoscopy. Surgery also had other advantages like improved quality of life for the first two years after intervention, although this difference disappeared with time. Similarly, surgery reduced the risk of developing malabsorption due to failure of the pancreas, but with longer follow-up this advantage became smaller. The studies seemingly showed no difference between endoscopy and surgery in complications after interventions. We also compared surgery with conservative treatment. The results of one trial suggested that surgery early in the condition achieved better pain relief and preservation of pancreatic function. For endoscopy versus surgery, the quality of the evidence for pain relief, quality of life and pancreatic function was moderate (according to GRADE). For both complications and mortality this was low, since the two trials were too small to make reliable conclusions. The quality of evidence regarding surgery versus conservative treatment was low, since the trial was small, which precluded drawing reliable conclusions regarding all outcomes.