Coelho 1993.

Methods	Single‐centre trial. Generation of allocation: unclear. Patients randomly and prospectively divided into three groups. Allocation concealment: unclear. Blinding: not performed. Follow‐up: unclear. Drop‐outs: none mentioned. Intention‐to‐treat: not mentioned. Sample size calculations: no.
Participants	Chronic calculous cholecystitis admitted for elective cholecystectomy. In‐ and exclusion criteria: not described. Comparability groups: well matched.
Interventions	LC versus SIC versus OC. LC: four‐trocar technique, carbon dioxide insufflated. SIC: right upper quadrant transverse incision of 5 to 8 cm. OC: right upper quadrant subcostal incision of 15 to 20 cm. Antibiotic prophylaxis: not mentioned. Intra‐operative cholangiography: not mentioned.
Outcomes	Primary and secondary outcome: not defined. Outcome measures: comparison of reduction in pulmonary function. Duration of follow‐up: not mentioned.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	B ‐ Unclear
Blinding? All outcomes	High risk
Free of selective reporting?	High risk
Free of other bias?	High risk	unclear duration of follow‐up