Lopez‐Cano 2012.

Methods	Randomised trial. Computerised randomisation
Participants	36 (mean age control group = 66 +/‐ 13.9 years, intervention group = 72 +/‐ 7.6 years), Male 18:18 Female
Interventions	Participants were randomised into a group undergoing placement of a large‐pore lightweight mesh in the intraperitoneal/onlay position at the time of surgery (n = 19) or to a control group (no mesh) (n = 17).
Outcomes	Incidence of parastomal hernia at 12 months (CT detected) and subcutaneous fat thickness at 12 months (CT measured)
Length of Follow Up	12 months
Notes	1 participant from the control group and 1 participant from the intervention group were lost to follow‐up.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation
Allocation concealment (selection bias)	Low risk	Allocation was concealed prior to surgery.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: Not possible to blind the surgeon as to which procedure was being performed
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The reporting radiologist assessing participant CT scans was blinded to the allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	8 of the 44 randomised participants were not included in the final analysis. Comment: Clear explanation of incomplete follow‐up data
Selective reporting (reporting bias)	Low risk	We identified no selective reporting.
Early Stopping	Low risk	Comment: Sample size calculation included. No evidence of early stopping