Abstract: Eight RCTs met the inclusion criteria. Six of the trials provided data for this review and all of these were at high risk of bias. Six trials randomised a total of 815 participants to subcutaneous closure (410 participants) or no subcutaneous closure (405 participants). Overall, 7.7% of participants (63/815 of participants) developed superficial surgical site infections and there was no clear evidence of a difference between the two intervention groups (RR 0.84; 95% CI 0.53 to 1.33; very low quality evidence). Only two trials reported superficial wound dehiscence, with 7.9% (17/215) of participants developing the problem. It is not clear whether the lack of reporting of this outcome in other trials was because it did not occur, or was not measured. There was no clear evidence of a between-group difference in the proportion of participants who developed superficial wound dehiscence in the trials that reported this outcome (RR 0.56; 95% CI 0.22 to 1.41; very low quality evidence). Only one trial reported deep wound dehiscence, which occurred in 8.3% (5/60) of participants. There was no clear evidence of a difference in the proportion of participants who developed deep wound dehiscence between the two groups (RR 0.25; 95% CI 0.03 to 2.11; very low quality evidence). Three trials reported the length of hospital stay and found no significant difference between groups (MD 0.10 days; 95% CI -0.45 to 0.64; very low quality evidence). We do not know whether this review reveals a lack of effect or lack of evidence of effect. The confidence intervals for these outcomes were wide, and significant benefits or harms from subcutaneous closure cannot be ruled out. In addition, none of the trials assessed the impact of subcutaneous closure on quality of life, long-term patient outcomes (the follow-up period in the trials varied between one week and two months after surgery) or financial implications to the healthcare provider. There is currently evidence of very low quality which is insufficient to support or refute subcutaneous closure after non-caesarean operations. The use of subcutaneous closure has the potential to affect patient outcomes and utilisation of healthcare resources. Further well-designed trials at low risk of bias are necessary.

Plain-language summary: We identified six randomised controlled trials that reported one or more of the outcomes we thought were important. There may have been flaws in trial conduct that could produce incorrect results. The six trials that provided data for this review included 815 participants (410 participants had subcutaneous closure of incisions and 405 participants did not). In the trials that reported the outcomes, overall 7% of participants developed superficial wound infection, 8% of participants developed superficial separation of wounds, and 8% of participants developed deeper separation of layers in both the groups but there was no clear evidence of a difference in incidence between the subcutaneous closure group and the no subcutaneous closure group. There was no clear evidence of a difference in the length of hospital stay between the groups. We do not know whether these results indicate that there is really no difference between subcutaneous closure and no subcutaneous closure, or that there are problems with study design that make it difficult to identify true differences between the two techniques. So significant benefits or harms of subcutaneous closure cannot be ruled out. Furthermore, no trial assessed the impact of subcutaneous closure on quality of life, long-term patient outcomes (trial follow-up periods varied between one week and two months after surgery) or financial implications to healthcare providers. There is currently no evidence to support or condemn subcutaneous closure after non-childbirth surgery. Further well-designed trials are necessary.