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Stents for the prevention of pancreatic fistula following pancreaticoduodenectomy

  1. Zhiyong Dong1,2,
  2. Jing Xu1,*,
  3. Zhen Wang3,
  4. Maxim S Petrov4

Editorial Group: Cochrane Upper Gastrointestinal and Pancreatic Diseases Group

Published Online: 26 JUN 2013

Assessed as up-to-date: 4 APR 2011

DOI: 10.1002/14651858.CD008914.pub2


How to Cite

Dong Z, Xu J, Wang Z, Petrov MS. Stents for the prevention of pancreatic fistula following pancreaticoduodenectomy. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD008914. DOI: 10.1002/14651858.CD008914.pub2.

Author Information

  1. 1

    The First Affiliated Hospital of Guangxi Medical University, Hepato-Pancreato-Biliary Surgery, Nanning, Guangxi, China

  2. 2

    Affiliated Hospital of Pu Tian University, Hepato-Pancreato-Biliary Surgery, Putian, Fujian Province, China

  3. 3

    The First Affiliated Hospital of Guangxi Medical University, Department of Gastrointestinal Surgery, Nanning, Guangxi, China

  4. 4

    The University of Auckland, Department of Surgery, Auckland, New Zealand

*Jing Xu, Hepato-Pancreato-Biliary Surgery, The First Affiliated Hospital of Guangxi Medical University, No.6, Shuang Yong Road, Nanning, Guangxi, 530021, China. jxuapr@yahoo.com.cn.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 26 JUN 2013

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Characteristics of included studies [ordered by study ID]
Kamoda 2008

MethodsRandomized clinical trial
Allocation sequence: unclear, only mentioned "allocated randomly".
Allocation concealment: unclear, no mentioned.
Blinding: unclear, no mention.

Follow-up: adequate, dropout: n = 1 (2.27%).

Intention-to-treat analysis (ITT): no, but used "per protocol analysis".

Informed consent: reported.

Sample size calculation: performed.


ParticipantsCountry: Japan. Single centre: Kobe University Hospital, from January 2003 to January 2007. Randomised No.: 44. Age: 23 patients ≧ 65 Years, 20 patients ≨ 65 years. Sex: Male/Female=15/28.
Inclusion criteria: Patients underwent a pancreaticoduodenectomy (PD) including pylorus-preserving PD for pancreas, periampullary, and bile duct tumours. Exclusion criteria: The study would be stopped when three unanticipated events occurred.

Definition of pancreatic fistula: According to the ISGPF or the John Hopkins

Conflicts of interest: no detail provided


Interventions44 Patients were randomly assigned into two groups.
Group 1: Pancreaticojejunostomy with an external stent (n = 22).
Group 2: Pancreaticojejunostomy with an internal stent (n = 22).


OutcomesThe main outcome measures were: Pancreas fistula, Events of pancreatitis, Pancreatic duct dilatation, Mortality, Postoperative hospital stay.


NotesOne patient in group 1 was excluded from this study because secondary fatty replacement of the remnant pancreas. 43 patients were analysed in finally.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskOnly mentioned "allocated randomly"

Allocation concealment (selection bias)Unclear riskOnly mentioned "allocated randomly"

Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned

Incomplete outcome data (attrition bias)
All outcomes
Low riskDetailed information, and dropouts: n = 1 (2.27%)

Selective reporting (reporting bias)Low riskAccording to the outcomes reported

Other biasUnclear riskNot mentioned

Pessaux 2011

MethodsRandomized clinical trial (www.clinicaltrials.gov: Clinical trial ID# NCT01068886)
Allocation sequence: central random numbers.
Allocation concealment: sealed envelopes. we considered both allocation sequence generation and allocation concealment as adequate.
Blinding: no mentioned.

Follow-up: adequate. All patients were reviewed 6 weeks after operation to complete the follow-up.

Dropout: n = 0.

Informed consent: reported.

Intention-to-treat analysis: used.

Sample size calculation: no performed.


ParticipantsCountry: Strasbourg, France.

Multicentre, between January 2006 and March 2009.

Randomised No.: 158. Age: no stent group=60.6±11.8 years; stent group=60.8±11.8 years.Gender: Male/Female = 86/72.
Inclusion criteria: Patients underwent Conventional or pylorus-preserving PD.

Exclusion criteria were age less than 18 years, emergency surgery.

Definition of pancreatic fistula: by ISGPF.

Conflicts of interest: No potential conflicts of interest.


Interventions158 patients who underwent PD were randomized intraoperatively to either receive an external stent inserted across the anastomosis to drain the pancreatic duct (n = 77) or no stent (n = 81).


OutcomesThe main outcome measures were:

Pancreatic fistula.

Overall morbidity rate.

Mortality rate.

Length of hospitalization.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskCentral random numbers

Allocation concealment (selection bias)Unclear riskSealed envelopes

Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned

Incomplete outcome data (attrition bias)
All outcomes
Low riskReported

Selective reporting (reporting bias)Low riskAccording to the detailed outcomes

Other biasUnclear riskNone detailed

Poon 2007

MethodsRandomized clinical trial (Registered in a clinical trial website of Hong Kong www.hkclinicaltrials.com, NO.:HKCTR-12)
Allocation sequence: random numbers.
Allocation concealment: sealed envelopes; we considered both allocation sequence generation and allocation concealment as adequate.
Blinding: no mentioned.

Follow-up: adequate. n = 0.

Dropout: n = 0.

Informed consent: reported.

Intention-to-treat analysis: used. but no detailed information about ITT analysis.

Sample size calculation: performed.


ParticipantsCountry: Hong Kong, China. Single centre: Department of Surgery, The University of Hong Kong, Queen Mary Hospital, between June 2000 and October 2006. Randomised No.: 120. Age: 67 patients ≦ 65 years, 53 patients ≩ 65 years. Sex: Male/Female = 72/48.
Inclusion criteria: Patients underwent elective pancreaticoduodenectomy for benign or malignant pathologies of pancreas or periampullary region. Exclusion criteria: Patients underwent emergency pancreaticoduodenectomy for trauma. Patients with ongoing acute pancreatitis at the time of operation. Patients were recruited before surgery but were found to have unresectable disease after laparoscopy or laparotomy.

Definition of pancreatic fistula: amylase-rich fluid (amylase concentration 3 times the upper limit of normal serum amylase level) collected from the peripancreatic drains after postoperative day 3 with a drainage volume of 10 mL per day.

Conflicts of interest: None.


Interventions120 Patients underwent pancreaticoduodenectomy with end-to-side pancreaticojejunal anastomosis were randomly assigned into two groups, duct-to-mucosa anastomosis was performed in all patients.
Group 1: An external stent inserted across the pancreaticojejunal (PJ) anastomosis into the pancreatic duct and brought out externally via the jejunal loop and abdominal wall (n = 60).
Group 2: no stent in the PJ anastomosis (n = 60).


OutcomesThe main outcome measures were: Pancreatic fistula or leakage. Overall morbidity rate. Hospital mortality rate. Postoperative hospital stay. No. of days to resume oral diet. No. of days on total parenteral nutrition.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandom numbers

Allocation concealment (selection bias)Unclear riskSealed envelopes

Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned

Incomplete outcome data (attrition bias)
All outcomes
Low riskDetailed information, and dropout: n=0

Selective reporting (reporting bias)Low riskAccording to the outcomes reported

Other biasUnclear riskNot mentioned

Tani 2010

MethodsA prospective randomized clinical trial (Registered at http://ClinicalTrials.gov NCT00628186). Allocation sequence: adequate.

Allocation concealment: adequate, used consolidated standards of reporting trials flow diagram, we considered both allocation sequence generation and allocation concealment as adequate.

Blinding: no mention.

Follow up: adequate.

Dropout: n = 0.

Informed consent: reported.

Intention to treat analysis: used.
Sample size calculation: performed.


ParticipantsCountry: Japan. Single centre: Wakayama Medical University Hospital, between April 2005 and August 2007. Randomised No.: 100. Age: 35 to 87years. Sex: Male/Female = 55/45.
Inclusion criteria: Patients underwent pancreaticoduodenectomy for pancreatic head and periampullary disease. Exclusion criteria: Patients with severe associated diseases that might prolong hospital stay. Patients whose conditions were diagnosed inadequately for this trial by a physician. Patients who could not have a pancreatic stent placed.

Definition of pancreatic fistula: The ISGPF definition.

Conflicts of interest: None.


Interventions100 Participants who underwent pancreaticoduodenectomy were randomly assigned into two groups.
Group 1: External drainage (n = 50).
Group 2: Internal drainage (n = 50).


OutcomesThe main outcome measures were: Postoperative hospital stay. Mortality and morbidity. Pancreas fistula. Delayed gastric emptying. Intra-abdominal haemorrhage. Intra-abdominal abscess.


NotesOne patient died in the hospital in group 1.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskUsed consolidated standards of reporting trials flow diagram

Allocation concealment (selection bias)Low riskUsed consolidated standards of reporting trials flow diagram

Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned

Incomplete outcome data (attrition bias)
All outcomes
Low riskDetailed information

Selective reporting (reporting bias)Low riskAccording to the outcomes reported

Other biasUnclear riskNot mentioned

Winter 2006

MethodsRandomized clinical trial
Allocation sequence: adequate, reported using a randomly generated number pattern. we considered both allocation sequence generation and allocation concealment as adequate.
Allocation concealment: adequate
Blinding: no mention

Follow-up: adequate, withdrawn n = 4.

Dropout: n = 0
Intention-to-treat analysis: no, but used per protocol analysis.
Sample size calculation: Performed.


ParticipantsCountry: U.S.A Single centre: Johns Hopkins Medicine IRB, 238 patients were accrued between March 8, 2004 and November 21, 2005. Randomized No.: 234. Age: 27-89 years. Sex: Male/Female = 132/102. Inclusion criteria: Patients underwent a pylorus preserving pancreaticoduodenectomy.

Definition of pancreatic fistula: by the local definition and ISGPF.

Conflicts of interest: None.


InterventionsIn patients with a soft pancreas: 113 patients were randomly assigned into two groups: Stent (n = 57), No Stent (n = 56). In patients with a hard pancreas: 121 patients were randomly assigned into two groups: Stent (n = 58), No Stents (n = 63).


OutcomesThe main outcome measures were: Mortality. Complications. Reoperation. Specific complications. Postoperative length of stay.


NotesAll patients underwent pancreaticoduodenectomy, but four patients were withdrawn from the study after enrolment and randomization, 234 patients who completed this study were analysed.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskRandomly generated number pattern

Allocation concealment (selection bias)Unclear riskRandomly generated number pattern

Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned

Blinding of participants and personnel (performance bias)
All outcomes
Unclear riskNot mentioned

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot mentioned

Incomplete outcome data (attrition bias)
All outcomes
Low riskDetailed information, and withdrawn n = 4

Selective reporting (reporting bias)Low riskAccording to the outcomes reported

Other biasUnclear riskNot mentioned

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Bree 2004Case report.

Chen 2004A randomized clinical trial, but not meet the inclusion criteria.

He 2004A randomized clinical trial, but not meet the inclusion criteria.

Imaizumi 2006Clinical controlled study, no used randomly assigned.

Kimura 2009Case control report.

Lee 2009A randomized clinical trial, but not meet the inclusion criteria.

Mullen 2005Controlled study, no used randomly assigned.

Ohwada 2002Non-randomized controlled study.

Roder 1999A prospective non-randomized observation study.

Schulick 2009A review.

Shukla 2010A review.

Smyrniotis 2010Clinical controlled study.

Tani 2005Clinical controlled study.

 
Characteristics of ongoing studies [ordered by study ID]
Frozanpor 2007

Trial name or titleRandomized Study Comparing the Effect of Plastic Stents to That of Expandable Metal Stents as Pre-Operative

MethodsAllocation: Randomized
Control: Active Control
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment

ParticipantsThe primary inclusion criteria are all patients with operable periampullary cancer and jaundice who have not previously undergone bile flow drainage

InterventionsProcedure: primary ERCP and secondary Whipple

OutcomesIntraoperative measurement of the inflammatory reaction in the liver, hepatoduodenal ligament and around the bile ducts with biopsies and culture from the bile

Stent dysfunction and cholangitis after ERCP and pre-operative bile flow relief. Postoperative complications. Time in the hospital. Cost. Quality of life analysis.

Starting dateJuly 2007

Contact informationFarshad Frozanpor Email: farshad.frozanpor@sodersjukhuset.se

NotesClinicalTrials.gov identifier: NCT00501176 http://www.clinicaltrial.gov/ct2/show/NCT00501176?term=pancreaticod

Fuyuhiko 2007

Trial name or titleA preventive effect of pancreatic duct stenting to decrease the rate of pancreatic fistula after pancreaticojejunostomy following pancreatoduodenectomy

MethodsParallel Randomized

ParticipantsAll adult patient who are anticipate to undergo pancreatoduodenectomy 2) reconstruction feasible for pancreaticojejunostomy 3) written informed consent

InterventionsStented group; Non-stented group

OutcomesRate and severity of pancreatic fistula, postoperative morbidity rate, postoperative hospital stay, hospital mortality rate

Starting date2007/12/01

Contact informationName: Motoi Fuyuhiko
Address: 1-1, Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan Japan
Telephone: 022-717-7205
Email: fmotoi@surg1.med.tohoku.ac.jp
Affiliation: Tohoku University Gastroenterological surgery

NotesClinicalTrials.gov Identifier: JPRN-UMIN000000952 http://apps.who.int/trialsearch/Trial.aspx?TrialID=JPRN-UMIN000000952

This trial has completed, but has not published the results

Kim 2007

Trial name or titleClosed Suction Drainage and Natural Drainage of the Pancreatic Duct in Pancreaticojejunostomy

MethodsAllocation: Randomized, Control: Active Control Endpoint Classification: Efficacy Study Intervention Model: Parallel Assignment Masking: Open Label Primary Purpose: Prevention

ParticipantsAll patients who undergo duct-to-mucosa pancreaticojejunostomy reconstruction after pancreatoduodenectomy in our institution

InterventionsProcedure: closed suction drainage of pancreatic duct
Procedure: natural drainage of pancreatic duct

Outcomespancreatic fistula rates

severity of pancreatic fistulas

Starting dateMarch 2007

Contact informationSun-Whe Kim, MD., PhD. Tel: 82-2-2072-2315 Email: sunkim@plaza.snu.ac.kr

NotesClinicalTrials.gov Identifier: NCT00679952 Website: http://www.clinicaltrial.gov/

Current status of trial: Recruiting

Kim 2010

Trial name or titleComparison of Feasibility Between Internal and External Pancreatic Drainage in Pancreaticoduodenectomy

MethodsAllocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Prevention

ParticipantsPatient who have malignant or benign disease which needs pancreatoduodenectomy
Patient age: ≥20 and ≤85

InterventionsExternal stent: Active Comparator Feeding tube insert at pancreatojejunostomy site as a stent. And stent tube is brought out through jejunal loop below the hepaticojejunostomy site and abdominal wall. Intervention: Procedure: Pancreatic stent

Internal stent: Active Comparator short (5cm) internal stent insertion at pancreatojejunostomy site Intervention: Procedure: Pancreatic stent

OutcomesEvidence of pancreatic fistula confirmed by serum and drain amylase

pancreatic endocrine and exocrine function by blood test, stool exam

Starting dateJanuary 2010

Contact informationContact: Sun-Whe Kim, M.D. 82-2-2072-2310 sunkim@plaza.snu.ac.kr
Contact: Jin-Young Jang, M.D. 82-2-2072-2194 jangjy4@gmail.com

NotesClinicalTrials.gov Identifier: NCT01023594 Website: http://www.clinicaltrial.gov/

Current status of trial: Recruiting

Pierre 2010

Trial name or titleExternal Pancreatic Duct Stent After Pancreaticoduodenectomy

MethodsAllocation: Randomized Control: Active Control Intervention Model: Parallel Assignment Masking: Open Label Primary
Purpose: Treatment

ParticipantsAll patients scheduled for elective PD, Confirmation of the soft pancreas or non dilated pancreatic duct during PD.

InterventionsProcedure: External pancreatic stent

OutcomesPancreatic fistula on postoperative day 30 Overall morbidity postoperative day 30

Starting dateJanuary 2006

Contact informationarnaud - jean-pierre, professor, Principal Investigator, University Hospital, University Hospital, Angers, France, 49933

NotesClinicalTrials.gov identifier: NCT01068886 Website: http://www.clinicaltrial.gov/

This trial was completed, but no publication now

Ramesh 2009

Trial name or titleAnastomotic Techniques in Pancreaticoduodenectomy

MethodsAllocation: Randomized Control: Active Control Intervention Model: Parallel Assignment Masking: Single Blind (Subject)
Primary Purpose: Treatment

ParticipantsPancreaticoduodenectomy for adenocarcinoma of the pancreatic head resectable tumour

InterventionsProcedure: type of anastomosis after pancreaticoduodenectomy

OutcomesMortality 90 days Yes
Hospital stay 90 days No
Need for postoperative intervention 90 days Yes
Major complication 90 days Yes

Starting dateJuly 2004

Contact informationHariharan Ramesh, MS MCh FRCS FACS
Tel: 2701992 ext.: 2036
hramesh@vsnl.com

NotesClinicalTrials.gov identifier: NCT00855985 Website: http://www.clinicaltrial.gov/

Current status of trial: Recruiting

 
Comparison 1. Stents (external and internal) versus no stents

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Pancreatic fistulas3512Risk Ratio (IV, Fixed, 95% CI)0.81 [0.59, 1.10]

 2 In-hospital mortality3512Risk Ratio (IV, Random, 95% CI)0.64 [0.23, 1.77]

 3 Reoperation3512Risk Ratio (IV, Random, 95% CI)0.67 [0.36, 1.22]

 4 Total hospital stay2278Mean Difference (IV, Fixed, 95% CI)-4.28 [-6.81, -1.75]

 5 Overall complications3512Risk Ratio (IV, Random, 95% CI)0.62 [0.24, 1.59]

    5.1 Wound infection
3512Risk Ratio (IV, Random, 95% CI)0.62 [0.24, 1.59]

 
Comparison 2. Internal stents versus no stents

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Pancreatic fistulas1Risk Ratio (IV, Fixed, 95% CI)Totals not selected

 2 In-hospital mortality1Risk Ratio (IV, Random, 95% CI)Totals not selected

 3 Reoperation1Risk Ratio (IV, Random, 95% CI)Totals not selected

 4 Total hospital stayOther dataNo numeric data

 5 Overall Complications1702Risk Ratio (IV, Random, 95% CI)0.97 [0.79, 1.18]

    5.1 Complications
1234Risk Ratio (IV, Random, 95% CI)0.99 [0.79, 1.23]

    5.2 Intra-abdominal abscess
1234Risk Ratio (IV, Random, 95% CI)1.38 [0.49, 3.85]

    5.3 Wound infection
1234Risk Ratio (IV, Random, 95% CI)0.71 [0.39, 1.29]

 
Analysis 2.4 Comparison 2 Internal stents versus no stents, Outcome 4 Total hospital stay.
Total hospital stay

StudyInternal stentsNo stents

Winter 20068 days (5 to 85 days)7 days (5 to 9 days)

 
Comparison 3. External stents versus no stents

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Pancreatic fistulas2278Risk Ratio (IV, Random, 95% CI)0.55 [0.35, 0.88]

 2 In-hospital mortality2278Risk Ratio (IV, Random, 95% CI)0.72 [0.20, 2.60]

 3 Reoperation2278Risk Ratio (IV, Random, 95% CI)0.76 [0.36, 1.60]

 4 Total hospital stay2278Mean Difference (IV, Random, 95% CI)-4.32 [-7.45, -1.19]

 5 Overall complications2556Odds Ratio (IV, Fixed, 95% CI)0.48 [0.25, 0.92]

    5.1 Delayed gastric emptying
2278Odds Ratio (IV, Fixed, 95% CI)0.42 [0.19, 0.93]

    5.2 Wound infection
2278Odds Ratio (IV, Fixed, 95% CI)0.62 [0.21, 1.81]

 
Comparison 4. Internal stents versus external stents

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Pancreatic fistulas2143Risk Ratio (IV, Random, 95% CI)1.12 [0.65, 1.92]

 2 In-hospital mortality2143Risk Ratio (IV, Random, 95% CI)0.33 [0.01, 7.99]

 3 Reoperation1100Risk Ratio (IV, Random, 95% CI)0.0 [0.0, 0.0]

 4 Total hospital stay1Mean Difference (IV, Random, 95% CI)Totals not selected

 5 Overall complications2429Risk Ratio (IV, Random, 95% CI)0.99 [0.47, 2.09]

    5.1 Intra-abdominal abscess
2143Risk Ratio (IV, Random, 95% CI)1.05 [0.33, 3.37]

    5.2 Delayed gastric emptying
2143Risk Ratio (IV, Random, 95% CI)0.85 [0.27, 2.70]

    5.3 Events of pancreatitis
143Risk Ratio (IV, Random, 95% CI)0.15 [0.01, 2.73]

    5.4 Wound infection
1100Risk Ratio (IV, Random, 95% CI)4.0 [0.46, 34.54]

 
Summary of findings for the main comparison. Stents for the prevention of pancreatic fistulas for pancreaticoduodenectomy

Stents for the prevention of pancreatic fistulas for pancreaticoduodenectomy

Patient or population: patients with pancreaticoduodenectomy
Settings:
Intervention: Stents for the prevention of pancreatic fistulas

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

ControlStents for the prevention of pancreatic fistulas

Internal stents versus no stentsSee commentSee commentNot estimable234
(1 study)
⊕⊕⊕Ο

Moderate quality1,3,4
Inadequte data reported for analyses

Stents (external and internal) versus no stents28 per 10022 per 100
(16 to 30)
RR 0.81
(0.59 to 1.1)
512
(3 studies)
⊕⊕⊕⊕

High quality3,4
Adequte data reported for analyses

External stents versus no stentsSee commentSee commentNot estimable234
(1)
⊕⊕⊕⊕

High quality3,4
Adequte data reported for analyses

Internal stents versus external stents25 per 10028 per 100
(16 to 48)
RR 1.12
(0.65 to 1.92)
143
(2 studies)
⊕⊕⊕Ο

Moderate quality2,3,4
Adequte data, but no detail about random allocation

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; RR: Risk ratio.

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 1. The included trial did not report all the data on complications.
2. The included trials did not report the study design and implementation very clearly, so the items of methodological quality were unclear.
3. The sample size of the five included studies was not very small.
4. All the five studies were randomised controlled trials.
 
Table 1. Study characteristics for included studies

Study IDCountryNumber of centresIntervention groupControl groupTotal number of patientsAgeMale: female



Intervention groupControl groupIntervention groupControl groupIntervention groupControl group

Winter 2006USA111511911612263 (27 to 89)67 (33 to 88)67:4865:54

Poon 2007Hong Kong16060606061±1262±1331:2941:19

Kamoda 2008Japan122212222NSNS8:147:14

Tani 2010Japan14950505070 (44 to 87)68 (35 to 84)28:2227:23

Pessaux 2011France87781778160.8+11.860.6+11.839:3847:34

 NS = Not stated