title: Stents for the prevention of pancreatic fistula following pancreaticoduodenectomy.
abstract: BACKGROUND
  Several studies have demonstrated that the use of pancreatic duct stents following pancreaticoduodenectomy is associated with a lower risk of pancreatic fistula. However, to date there is a lack of accord in the literature on whether the use of stents is beneficial and, if so, whether internal or external stenting, with or without replacement, is preferable. This is an update of a systematic review.
  
  
  OBJECTIVE
  To determine the efficacy of pancreatic stents in preventing pancreatic fistula after pancreaticoduodenectomy.
  
  
  METHODS
  We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science, and four major Chinese biomedical databases up to November 2015. We also searched several major trials registers.
  
  
  METHODS
  Randomized controlled trials (RCTs) comparing the use of stents (either internal or external) versus no stents, and comparing internal stents versus external stents, replacement versus no replacement following pancreaticoduodenectomy.
  
  
  METHODS
  Two review authors independently extracted the data. The outcomes studied were incidence of pancreatic fistula, need for reoperation, length of hospital stay, overall complications, and in-hospital mortality. We showed the results as risk ratio (RR) or mean difference (MD), with 95% confidence interval (CI). We assessed the quality of evidence using GRADE (http://www.gradeworkinggroup.org/).
  
  
  RESULTS
  We included eight studies (1018 participants). The average age of the participants ranged from 56 to 68 years. Most of the studies were conducted in single centers in Japan (four studies), China (two studies), France (one study), and the USA (one study). The risk of bias was low or unclear for most domains across the studies. Stents versus no stentsThe effect of stents on reducing pancreatic fistula in people undergoing pancreaticoduodenectomy was uncertain due to the low quality of the evidence (RR 0.67, 95% CI 0.39 to 1.14; 605 participants; 4 studies). The risk of in-hospital mortality was 3% in people who did receive stents compared with 2% (95% CI 1% to 6%) in people who had stents (RR 0.73, 0.28 to 1.94; 605 participants; 4 studies; moderate-quality evidence). The effect of stents on reoperation was uncertain due to wide confidence intervals (RR 0.67, 0.36 to 1.22; 512 participants; 3 studies; moderate-quality evidence). We found moderate-quality evidence that using stents reduces total hospital stay by just under four days (mean difference (MD) -3.68, 95% CI -6.52 to -0.84; 605 participants; 4 studies). The risk of delayed gastric emptying, wound infection, and intra-abdominal abscess was uncertain (gastric emptying: RR 0.75, 95% CI 0.24 to 2.35; moderate-quality evidence) (wound infection: RR 0.73, 95% CI 0.40 to 1.32; moderate-quality evidence) (abscess: RR 1.38, 0.49 to 3.85; low-quality evidence). Subgroup analysis by type of stent provided limited evidence that external stents lead to lower risk of fistula compared with internal stents. External versus internal stentsThe effect of external stents on the risk of pancreatic fistula, reoperation, delayed gastric emptying, and intra-abdominal abscess compared with internal stents was uncertain due to low-quality evidence (fistula: RR 1.44, 0.94 to 2.21; 362 participants; 3 studies) (reoperation: RR 2.02, 95% CI 0.38 to 10.79; 319 participants; 3 studies) (gastric emptying: RR 1.65, 0.66 to 4.09; 362 participants; 3 studies) (abscess: RR 1.91, 95% CI 0.80 to 4.58; 362 participants; 3 studies). The rate of in-hospital mortality was lower in studies comparing internal and external stents than in those comparing stents with no stents. One death occurred in the external-stent group (RR 0.33, 0.01 to 7.99; low-quality evidence). There were no cases of pancreatitis in participants who had internal stents compared with three in those who had external stents (RR 0.15, 0.01 to 2.73; low-quality evidence). The difference between internal and external stents on total hospital stay was uncertain due to the wide confidence intervals around the average effect of 1.7 days fewer with internal stents (9.18 days fewer to 5.84 days longer; 262 participants; 2 studies; low-quality evidence). The analysis of wound infection could not exclude a protective effect with either approach (RR 1.41, 0.44 to 4.48; 319 participants; 2 studies; moderate-quality evidence). Operative replacement of pancreatic juice versus not replacing pancreatic juice There was insufficient evidence available from a small trial to ascertain the effect of replacing pancreatic juice.
  
  
  CONCLUSIONS
  This systematic review has identified limited evidence on the effects of stents. We have not been able to identify convincing direct evidence of superiority of external over internal stents. We found a limited number of RCTs with small sample sizes. Further RCTs on the use of stents after pancreaticoduodenectomy are warranted.
authors.affiliation: Department of Surgery, The First Affiliated Hospital of Jinan University, No.613, HuangPu Avenu West, Guangzhou, Guangdong, China, 510630.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Dong
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Maxim S
authors.initials: MS
authors.lastname: Petrov
mesh_terms: D017052:Hospital Mortality; D006801:Humans; D010185:Pancreatic Fistula / Q000517:prevention & control*; D016577:Pancreaticoduodenectomy / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D012086:Reoperation; D015607:Stents / Q000145:classification*; D013997:Time Factors; D016896:Treatment Outcome