Trew 2017.

Study characteristics
Methods	Unit of randomisation: women Method of randomisation: via telephone to an interactive voice response system or via electronic case report form centralised at the University of Glasgow Time of randomisation: following primary surgery, prior to closure of abdomen Blinding: women blinded; surgeons analysing recordings blinded; operating surgeons not blinded Multi‐centre study
Participants	Premenopausal women aged 18 to 46 years, undergoing gynaecological laparoscopic surgery with a planned, clinically indicated second‐look laparoscopy 4 to 12 weeks N = 66 35 randomised to intervention and 31 to control Dropouts: 3 women (1 from the control group and 2 from the intervention group) withdrew consent prior to second look laparoscopy Age: mean age 33.6 Baseline characteristics: in the intervention group, more women were smokers and fewer had a history of treatment for uterine fibroids. Otherwise, no significant differences stated Indication for surgery: not clearly stated, but all women wished to maintain fertility Pre‐existing adhesions: 87.9% of the intervention group and 60.0% of the control group had pre‐existing adhesions Aetiology of pre‐existing adhesions: not clearly stated Microsurgery: surgery was performed using the basic tenets of microsurgery Additional surgical procedures: not clearly stated Location: three centres in Germany and one in Greece Timing: November 2013 to June 2014
Interventions	Dextran aldehyde and polyethylene glycol amine versus no treatment Other adjuvants used: none stated Second look laparoscopy: Timing: 4 to 12 weeks after initial surgery Surgeon blinded: not clearly stated Adhesiolysis: not clearly stated
Outcomes	Adhesions at second look laparoscopy: Adhesion score (severity and extent) Adhesion incidence Adverse events
Notes	Funding provided by Actamax Surgical Materials LLC Video recording performed both at initial surgery and second‐look laparoscopy Power calculation not performed for efficacy analysis Clinicaltrials.gov register number: NCT02260115
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Randomization was stratified by surgeon and by surgical subgroup. Randomization was conducted in permuted blocks of two within each stratum to ensure approximate treatment balance within each surgeon and subgroup at the end of the study"
Allocation concealment (selection bias)	Low risk	Quote: "Allocations were obtained by telephone to an interactive voice response system or via the electronic case report form managed by the Robertson Centre for Biostatistics, University of Glasgow, so that allocations were concealed from study sites until the time of randiomization."
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	women blinded, personnel not blinded operating surgeons not blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Following the SLL, copies of paired videos for the primary surgery (with application section removed) and SLL were provided to the blinded evaluator assigned to assess adhesions." "The independent blinded reviewer assessing the postoperative adhesions on SLL videotape whilst being blind to the randomisation allocation of the patient would believe, if they observed any residual material to be present, that a subject had received hydrogel during their primary surgery"
Incomplete outcome data (attrition bias) All outcomes	Low risk	12 of 78 women were not randomised, evaluated in the initial usage group. 3/66 randomised women lost to follow‐up
Selective reporting (reporting bias)	Low risk	All outcomes stated in trial registry were reported ‐ NCT02260115
Other bias	Low risk	"Despite randomisation, statistically significantly more subjects in the treatment group had baseline adhesions"