Johns 2001.

Study characteristics
Methods	Truly randomised, third party–blinded study (randomisation schedule) Multi‐centre: 16 centres in the USA and Europe Power calculation: no
Participants	Women aged 18 to 46 years, undergoing peritoneal cavity surgery by laparotomy Intention‐to‐treat: no Exclusion criteria: diabetes, haemochromatosis, hepatic disorders, renal disorders, lymphatic disorders, haematological disorders, autoimmune disorders, coagulation disorders, patients with pelvic or abdominal infection, patients receiveing cancer therapy, postoperative hydrotubation, anticoagulants, fibrin glue or other thrombogenic agents at initial surgery. N = 265 131 randomised to gel and 134 to Ringer's lactate Dropouts: 16 patients did not return for SLL. Age: mean age not stated Baseline characteristics: No significant differences in severity or extent of adhesions at baseline Indication for surgery: variety of indications Pre‐existing adhesions: present in the majority of women Aetiology of pre‐existing adhesions: not clearly stated Microsurgery: no Additional surgical procedures: not clearly stated Timing: not clearly stated
Interventions	0.5% ferric hyaluronate gel versus Ringer's lactate Volume: 300 mL Ringer's lactate or Intergel instilled at the end of the procedure Antibiotics: no Second‐look laparoscopy: 6 to 12 weeks after primary procedure
Outcomes	Analysed in review Adhesions present at second‐look laparoscopy Improvement in adhesion score (AFS) Deterioration in adhesion score (AFS) Other outcomes Shift in mAFS adhesion score Per cent reduction in mAFS score Severity and extent of adhesions (median and standard deviation) Pregnancy rates: no
Notes	Adhesion scoring system used AFS adhesion score mAFS adhesion score Funded by Lifecore Biomedical Inc
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "At the time of initial surgical procedure, patients were assigned the next available study number corresponding to study device or control solution as determined by the randomization schedule"
Allocation concealment (selection bias)	Low risk	Study device or control solution was maintained in a sealed carton until decision to enrol the participant was made
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Initial surgical team not blinded to allocation. Not clearly stated whether women blinded to allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinded independent review of adhesion data as a quality assurance check
Incomplete outcome data (attrition bias) All outcomes	Low risk	281 randomly assigned women receiving treatment—a total of 265 completed the study. Quote: "Of the 16 patient[s] who did not return for laparoscopy, 9 women discontinued for reasons unrelated to treatment. Although treatment‐related discontinuation could not be ruled out in the other seven women, a similar number were present in the treatment (N = 4) and control (N = 3) groups"
Selective reporting (reporting bias)	Unclear risk	Data presented in full for all outcomes specified, however, no study protocol or trial registry identified for comparison
Other bias	Low risk