Liu 2015.

Study characteristics
Methods	Unit of randomisation: women Method of randomisation: central web‐based programme Time of randomisation: after completion of surgery Blinding: women blinded. Surgeons analysing recordings blinded. Multi‐centre trial
Participants	Women aged 18 to 45 years, undergoing laparoscopic surgery for removal of adhesions, myomas, ovarian cysts, or endometriotic cysts, with negative pregnancy tests Intention‐to‐treat: yes Exclusion criteria: acute or severe infection, autoimmune disease, abnormal liver or renal function (ALT or creatinine > 50% upper normal limit), abnormal cardiovascular function (grade III and above), abnormal blood coagulation, medical history of peripheral vascular disease, alcohol or drug abuse, mental illness, known or suspected intolerance to hyaluronan or derivatives, use of anti‐inflammatory drugs, use of anticoagulant, fibrin glue, thrombogenic agents, anti‐adhesion agents used during procedure, concurrent peritoneal grafts or tubal implantation. N = 216 108 randomised to intervention and 108 to control Dropouts: 1 woman in intervention group was incorrectly randomised and did not receive the allocated intervention. 19 women (14 control and 5 intervention) did not show up for second‐look laparoscopy. Age: mean age 29.53 in intervention group and 29.95 in control group Baseline characteristics: in the intervention group, severity of pre‐existing adhesions was significantly greater than in the control group. No other significant differences Indication for surgery: variety of indications Pre‐existing adhesions: present in the majority of women Aetiology of pre‐existing adhesions: mostly previous surgery, or chronic infections, or both Microsurgery: no Additional surgical procedures: various extra procedures performed on a number of women Location: 6 centres in China Timing: June 2011 to April 2013 Study duration: 12 weeks
Interventions	Cross‐linked hyaluronic acid versus saline Other adjuvants used: none stated Second look laparoscopy: Timing: 8 to 10 weeks after initial surgery Surgeon blinded: not stated Adhesiolysis: not stated
Outcomes	Adhesions at second‐look laparoscopy: Adhesion score (mAFS) Adhesion incidence Number of sites with adhesions Incidence of moderate or severe adhesions Adverse events
Notes	Study supported by grants from BioRegen Biomedical (Changzhou) Co Ltd Video recording taken at initial surgery and second‐look laparoscopy Power calculation: stated 108 women needed in each arm Clinicaltrials.gov register number: NCT02166554
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were assigned at random to either the NCH gel or control group in a 1:1 ratio through a central web‐based program."
Allocation concealment (selection bias)	Low risk	women were only assigned to control or treatment group after the first‐look laparoscopy.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	women blinded, operators not blinded due to difference in viscosity of intervention versus control
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All videos were provided to 2 qualified reviewers for blinded assessment. To ensure minimal interobserver variability, adhesion scoring in the blinded reviewer assessments was compared, and any discrepancies were settled by the principal investigator."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	14 lost to follow‐up past randomisation to control; 5 lost to follow‐up past randomisation to treatment; 1 patient incorrectly randomised
Selective reporting (reporting bias)	Low risk	All outcomes stated in trial registry are reported ‐ NCT02166554
Other bias	Low risk	Severity of pre‐existing adhesions significantly greater in NCH gel compared to control group.