Ninomiya 1998.

Methods	Randomised clinical trial.
Participants	Country: Japan. Number randomised: 20. Mean age: 52 years. Females: 12 (60%). Inclusion criteria: 1. Laparoscopic cholecystectomy for symptomatic cholelithiasis. Exclusion criteria: Choledocholithiasis Cardiovascular or renal disorders Serious complications.
Interventions	Participants were randomly assigned to two groups: Group 1: abdominal wall lift (n = 10). Group 2: pneumoperitoneum with 10 mm Hg pressure (n = 10). Device used for abdominal lift: subcutaneous device.
Outcomes	The main outcome measure was operating time.
Notes	Attempts were made to contact the author in February 2007.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: This information was not available.
Allocation concealment (selection bias)	Unclear risk	Comment: This information was not available.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: This information was not available.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: This information was not available.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: This information was not available.
Selective reporting (reporting bias)	High risk	Comment: Important outcomes were not reported.
Vested interest bias	Unclear risk	Comment: This information was not available.