Different surgical approaches to access the infrarenal abdominal aorta during an operation to repair an abdominal aortic aneurysm

Background

There has been a lot of debate in the surgical literature about the best way to surgically access the infrarenal abdominal aorta during an operation to repair an abdominal aortic aneurysm (AAA; a ballooning of an artery (blood vessel) which occurs in the major artery in the abdomen (aorta)). Two approaches are commonly used: the retroperitoneal (RP) approach and the transperitoneal (TP) approach. Both approaches appear to have advantages and disadvantages. Many trials comparing RP and TP aortic surgery have been published with conflicting results. The aim of this Cochrane review is to assess the effectiveness and safety of the TP versus RP approach for planned surgical open AAA repair on mortality, complications, hospital stay and blood loss.

Key results

We included four small randomized controlled trials (RCTs) (129 participants) after we searched the literature up to May 2015). There were no differences between RP and TP for death. Our analysis seems to show a trend that RP might increase the complications such as hematoma (swelling of clotted blood), chronic wound pain and abdominal wall hernia compared with TP but there were variations between the included trials. We found that RP led to lower blood loss, and shorter hospital stay and ICU stay compared with TP but there were no differences between the two approaches for operating time and aortic cross-clamp time (length of time a surgical instrument, used to clamp the aorta and separate the circulation from the outflow of the heart, is used).

Quality of the evidence

Three of the four included trials had methodological weaknesses, such as unclear randomisation methods, and no reporting of blinding of the people assessing the outcome which compromised the value of their results. In addition, the included trials only included a small number of people, there were few outcomes reported, there was a relatively short follow-up and there were inconsistencies between the included trials resulting in very low to low quality of the evidence. More large-scale RCTs of the RP approach versus the TP approach for planned surgical open AAA repair are needed.

Authors' 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.

Read the full 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.

Objectives: 

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.

Search strategy: 

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.

Selection criteria: 

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.

Data collection and analysis: 

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.

Main 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).

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