Buimer 2008.

Methods	This was a 2‐arm, parallel group RCT of wound healing method after local excision and primary closure of active HS lesions
Participants	The trial included 200 participants with a clinical diagnosis of HS and symptomatic lesion(s), "i.e. those with discharge, inflammation, infiltration, or suspected abscesses"
Interventions	2 groups, randomised to the following: local excision and primary closure (PC) ‐ 76 participants, the dropout rate was not stated local excision and primary closure over a 5 x 5 cm gentamicin‐collagen (GC) sponge ‐ 124 participants, the dropout rate was not stated
Outcomes	Wound complications classified as dehiscence, infection, dehiscence and infection, or seroma after 1 week and 3 months Local recurrence rate at 3 months Time to complete wound healing
Notes	The authors stated in the paper that there was no significant commercial sponsor involvement We were unable to contact the authors to clarify risks of bias and other study details
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The paper gave no details on the random sequence generation; however, the study report stated that there was an imbalance in randomisation due to early cessation of the study. The report did not mention whether the randomisation was intended to be in a 1:1 ratio, so we could not quantify the degree of imbalance in randomisation (76 primary closures, 124 gentamicin sponges inserted)
Allocation concealment (selection bias)	Unclear risk	The paper provided no details
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were blinded under general anaesthetic but postoperatively may have been able to detect the sponge inserted in the wound. There was no description of any special measures to ensure blinding of personnel, who would otherwise have been aware of treatment allocation from the operation notes
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	The paper provided no details
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The paper provided no details, including no participant flow diagram
Selective reporting (reporting bias)	Unclear risk	There was no mention of prospective registration
Other bias	Unclear risk	It was unclear whether participants or surgical procedures were the unit of randomisation, i.e., was more than 1 procedure performed in any individuals?