title: Transperitoneal versus retroperitoneal approach for elective open abdominal aortic aneurysm repair.
abstract: BACKGROUND
  There has been extensive debate in the surgical literature regarding the optimum surgical access approach to the infrarenal abdominal aorta during an operation to repair an abdominal aortic aneurysm. The published trials comparing retroperitoneal (RP) and transperitoneal (TP) aortic surgery show conflicting results.
  
  
  OBJECTIVE
  To assess the effectiveness and safety of the transperitoneal versus retroperitoneal approach for elective open abdominal aortic aneurysm repair on mortality, complications, hospital stay and blood loss.
  
  
  METHODS
  The Cochrane Vascular Trials Search Co-ordinator searched the Cochrane Vascular Specialised Register (last searched May 2015) and CENTRAL (2015, Issue 4) and trials databases (May 2015). The review authors searched the Chinese Biomedical Literature Database and other resources including clinical trials registers.
  
  
  METHODS
  We included randomized controlled trials (RCTs) that assessed the TP approach versus the RP approach for elective open abdominal aortic aneurysm (AAA) repair. We evaluated the outcomes of mortality, complications, intensive care unit (ICU) stay, hospital stay, blood loss, aortic cross-clamp time and operating time. Two review authors independently selected RCTs against the inclusion criteria. We resolved any disagreements by discussion with a third review author.
  
  
  METHODS
  Two review authors independently extracted data from the included trials. We resolved any disagreements by discussion with a third review author. Two review authors independently assessed the risk of bias according to a standard quality checklist provided by Cochrane Vascular.
  
  
  RESULTS
  We included four RCTs, with a combined total of 129 participants, that assessed the TP approach versus the RP approach for elective open AAA repair. The overall quality of the evidence was low to very low because of the low methodological quality of the included trials (unclear random sequence generation method and allocation concealment, and no blinding of outcome assessors), small sample sizes, small number of events, high heterogeneity and inconsistency between the included trials, no power calculations and relatively short follow-up. There were no differences between the RP approach and the TP approach regarding mortality (odds ratio (OR) 0.32, 95% CI 0.01 to 8.25; 110 participants; four trials; P = 0.49; I² statistic = 0%; very low quality evidence). However, the RP approach may increase complications, such as hematoma (OR 0.90, 95% CI 0.13 to 6.48; 75 participants; two trials; P = 0.92; very low quality evidence), chronic wound pain (OR 2.20, 95% CI 0.36 to 13.34; 48 participants; one trial; P = 0.39; very low quality evidence) and abdominal wall hernia (OR 10.76, 95% CI 0.55 to 211.78; 48 participants; one trial; P = 0.12; very low quality evidence) compared with the TP approach in the patients for elective open AAA repair, but the confidence intervals (CIs) were wide. The RP approach reduced the blood loss (mean difference (MD) -504.87 mL, 95% CI -779.19 to -230.56; 129 participants; four trials; P = 0.003; very low quality evidence), ICU stay (MD -19.00 hours, 95% CI -31.41 to -6.59; 83 participants; two trials; P = 0.003; low quality evidence) and hospital stay (MD -3.14 days, 95% CI -4.82 to -1.45; 129 participants; four trials; P = 0.0003; low quality evidence). There were no differences between the RP approach and the TP approach regarding aortic cross-clamp time (MD 0.69 mins, 95% CI -7.23 to 8.60; 129 participants; four trials; P = 0.86; very low quality evidence) and operating time (MD -15.94 mins, 95% CI -34.76 to 2.88; 129 participants; four trials; P = 0.10; very low quality evidence).
  
  
  CONCLUSIONS
  Very low quality evidence from four small RCTs indicates that the RP approach did not have advantages over the TP approach for elective open AAA repair in terms of mortality. Moreover, the RP approach may increase the risk of postoperative wound complications although the CIs were wide.Low quality evidence shows that the RP approach could reduce blood loss, hospital stay and ICU stay compared with the TP approach. Very low quality evidence shows no differences between the RP approach and TP approaches in aortic cross-clamp time and operating time.Further large-scale RCTs of the RP approach versus TP approach for elective open AAA repair are required.
authors: Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, No. 199, Donggang West Road, Lanzhou City, Gansu, China, 730000.
authors: Bin
authors: B
authors: Ma
authors: Ya-Nan
authors: YN
authors: Wang
authors: Kuang-yang
authors: KY
authors: Chen
authors: Yulong
authors: Y
authors: Zhang
authors: Hui
authors: H
authors: Pan
authors: KeHu
authors: K
authors: Yang
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D017558:Elective Surgical Procedures / Q000379:methods* / Q000401:mortality; D006801:Humans; D010537:Peritoneum; D016032:Randomized Controlled Trials as Topic; D012187:Retroperitoneal Space