The use of O-ring retractors at Caesarean section : A systematic review and meta analysis

O-ring retractors (Alexis/Mobius) have been shown to reduce the risk of Surgical site infection (SSI) following general abdominal surgery. The benefit at caesarean section (CS) remains to be established given the relatively high cost.

To assess the efficacy of O-ring retractors when used at CS.

Systematic review and meta-analysis. Electronic databases were searched from inception of each database until January 2018. No language restrictions were applied. All randomised controlled trials (RCTs) which compared the use of an O-ring retractor to routine care at CS were included. Primary outcome was SSI. Secondary outcomes were operating time, estimated blood loss, need for blood transfusion, need to exteriorise the uterus, requirement for additional postoperative analgesia and adequate operative field visualisation. Analysis was performed using Revman 5.3.

6 RCTs were included in the qualitative synthesis and the meta-analysis. This included 1669 women. The use of O-ring retractors did not reduce the risk of SSI when used at CS RR 0.76 (95% CI 0.34-1.70). Nor did the use of O-ring retractors reduce the operating time, estimated blood loss, the need for blood transfusion or the need for additional postoperative analgesia. The use O-ring retractors did reduce the need for exteriorisation of the uterus RR 0.48 (95% CI 0.33-0.69), and did increase the rate of adequate visualisation of the operative field RR 1.05 (95% CI 1.00-1.10). In a planned subgroup analysis there was a reduction in the rate of SSI with the use of O-ring retractors in women with a BMI < 35 RR 0.34(95% CI 0.12-0.98).

This review has shown that O-ring retractors do not reduce the incidence of the common measurable complications of CS; SSI, blood loss, need for blood transfusion and need for additional postoperative analgesia. There may be a subgroup where these retractors are useful, but present evidence does not justify their routine use at CS.