Uden 1993.

Study characteristics
Methods	Study design: prospective randomised controlled trial Randomisation technique: random allocation Allocation concealment: reported Inclusion criteria: well explained Exclusion criteria: well explained Lost to follow‐up: not reported Baseline variables: matching between both limbs of the trial Intention‐to‐treat analysis: not reported Sample size calculations (power of the study): reported
Participants	Country: Sweden Number of participants: FG: 36 and NFG: 32 Age (years): FG 73 (42‐89); NFG 70 (40‐84)
Interventions	FG: Tisseel®was applied under skin flaps following breast and axillary surgery Types of surgical intervention: modified radical mastectomy Confounding interventions: none
Outcomes	Primary: incidence of seroma Secondary: wound infection length of seroma drainage in days mean volume of seroma total volume of seroma complications length of hospital stay
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random allocation
Allocation concealment (selection bias)	High risk	No clear reporting
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	High risk	Not reported
Selective reporting (reporting bias)	Low risk	No
Other bias	Low risk	Inclusion, exclusion criteria, ethics approval and conflict of interest declaration was adequately reported