Hewlett 1996.

Methods	2‐arm RCT undertaken in the UK
Participants	People undergoing spinal, orthopaedic or abdominal surgery; in total 77 participants were randomised. Exclusion criteria: people admitted to hospital for minimally‐invasive surgical techniques
Interventions	Group A (n = 39): absorbent dressing (Mepore, Mölnlycke Health Care) Group B (n = 37): film dressing (Opsite, Smith & Nephew) Manufacturers' instructions were followed when applying and removing dressings (no further details provided). Treatment was for a maximum of 10 days.
Outcomes	Primary outcome: not reported. Secondary outcomes: cost (dressing cost to complete healing)
Notes	Trial outcome data: see Table 12 Follow‐up: unclear. Trial information retrieved from a poster report only. Infection not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided in poster report.
Allocation concealment (selection bias)	Unclear risk	No information provided in poster report.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information provided in poster report.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information provided in poster report.
Selective reporting (reporting bias)	Unclear risk	No information provided in poster report.
Other bias	Unclear risk	No information provided in poster report.