Keckstein 1996.

Methods	Unit of randomisation: ovary Method of randomisation: toss of a coin Time of randomisation: at completion of surgery Blinding: surgeon at second‐look laparoscopy not aware of allocation
Participants	Patients undergoing bilateral ovarian cystectomy by laparoscopy N = 25 14 participants with bilateral endometriomas, 6 with ovarian cysts and endometriosis, and 5 with ovarian cysts only Dropouts: 8, not stated why Some participants also underwent adhesiolysis and removal of endometriosis Indication for surgery: ovarian cysts; not specifically participants with infertility Pre‐existing adhesions: some (but participants with dense adhesions excluded) Cause of adhesions: not stated (endometriosis included) Microsurgery: no Timing not stated Country: Germany (1 centre)
Interventions	Oxidised regenerated cellulose on ovary vs uncovered opposite ovary Other adjuvants used: none Suturing: 9 of 17 in the oxidised regenerated cellulose group; 3 of 17 in the non‐oxidised regenerated cellulose group Second‐look laparoscopy Timing: 8 to 30 weeks after initial surgery Surgeon unaware: not stated Adhesiolysis: not stated
Outcomes	Adhesions at second‐look laparoscopy: 8 to 30 weeks Incidence (per ovary) of de novo adhesions Severity: graded as filmy, vascular, or dense Area: estimated % of ovarian surface Adverse effects Pregnancy data nil
Notes	Power calculations: nil Analysis sponsored by Johnson & Johnson only after study was completed First presented as abstract in 1994 No photographic or video documentation No intention‐to‐treat analysis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Coin tosses were used as a simple method of randomisation Quote: "the random assignment of one ovary for wrapping with Interceed was revealed to the surgeon after a coin toss"
Allocation concealment (selection bias)	Low risk	Coin toss took place intraoperatively
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Unit of randomisation was each ovary, so all women acted as their own controls Surgeon was not blinded, but treatment allocation took place intraoperatively: "at the end of cystectomy the random assignment of one ovary for wrapping with Interceed [...] was revealed to the surgeon after a coin toss"
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Study does not state whether the assessor during SLL was blinded to initial treatment
Incomplete outcome data (attrition bias) All outcomes	High risk	8 dropouts (n = 25); no reasons stated as to why participants did not return for SLL
Selective reporting (reporting bias)	Unclear risk	Data presented as numbers of cases and percentages, as well as graphically. P values stated for significant outcomes. No omission of outcomes and no subsets of data. However, no pre‐published protocol identified
Other bias	Low risk	No other bias identified