Cameron 1987.

Methods	RCT Methods to control for contributory patient factors: none described
Participants	Age: Group 1 (mean): 60.2 years Group 2 (mean): 61.6 years Gender: Group 1: 56.0% female Group 2: 54.5% female Type of incision: Group 1: midline 66.7%; paramedian 33.3% Group 2: midline 56.0%; paramedian 44.0% Type of surgery: Group 1: emergent 19.6%; biliary 29.8%, gastric 17.7%, colon 29.1%, other 23.4% Group 2: emergent 19.9%; biliary 32.9%, gastric 23.1%, colon 21.0%, other 23.1% Contamination classification of included participants: Group 1: clean 77.3%, clean‐contaminated 9.2%, contaminated 13.5% Group 2: clean 79.7%, clean‐contaminated 6.3%, contaminated 14.0% Pre‐operative antibiotic use: "antibiotic prophylaxis was given according to the surgeon's usual routine" Prognostic patient factors: Group 1: obesity 26%, corticosteroid use 1.4%, jaundice 3.5% Group 2: obesity 24%, corticosteroid use 2.1%, jaundice 3.5% Inclusion criteria: patients undergoing laparotomy by vertical abdominal incision Exclusion criteria: patients who were being re‐operated on via the original incision were excluded
Interventions	Comparisons reported: Group 1 Suture: polypropylene (monofilament, non‐absorbable) Suturing technique: interrupted, "figure‐of‐eight" Closure method: mass Group 2: Suture: PDS (monofilament, slowly absorbable) Suturing technique: interrupted, "figure‐of‐eight" Closure method: mass Surgeon characteristics: Group 1: senior resident 56.0%, junior resident 40.4% Group 2: senior resident 52.4%, junior resident 46.8%
Outcomes	Incisional hernia: no definition provided Follow‐up duration: minimum 12 months (mean 14.7 months) Wound infection: "discharge of pus, up to one month of follow‐up" Wound dehiscence: "burst abdomen" Suture sinus or fistula: no definition provided
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information provided
Allocation concealment (selection bias)	Low risk	"At the end of the operation, the circulating nurse drew a sealed envelope and informed the surgeon of the suture to be used."
Blinding (performance bias and detection bias) All outcomes	Low risk	"This assessment was 'double‐blind', as neither the examiner nor the participant knew which suture had been used."
Incomplete outcome data (attrition bias) All outcomes	High risk	High loss to follow‐up (51/141 in group 1, 43/143 in group 2)
Selective reporting (reporting bias)	Low risk	Hernia (at least 1 year); dehiscence and wound infection outcomes all reported
Other bias	Low risk	The study appears to be free of other sources of bias