Sgourakis 2002.

Methods	Randomised clinical trial comparing laparoscopic surgery vs pre‐operative ERCP and surgery. Single centre. Study commenced April 1997, completed August 2000. Follow‐up: drop‐outs not reported. Median postoperative 22.36 months (7 to 36). Sample size calculations: no.
Participants	Athens, Greece. 78 pts randomised (36 Group A, 42 Group B) with high risk for CDS on USS and/or biochemical criteria. ASA I or II pts. 8 pts excluded because of 'poor performance' status. Further 6 refused consent.
Interventions	Laparoscopic group ‐ transcystic and choledochotomy approaches described in detail. In ERCP group ‐ surgery performed usually within 2 days.
Outcomes	Primary clearance success, morbidity, mortality, median hospital stay.
Notes	8/36 of surgical arm (Group A) and 10/42 endoscopy arm (Group B) had no CBDS found at the time of the procedure. No explanation given for choice of transcystic or direct CBD approaches in Group A. 1 pt in each group with CBDS in situ at end of trial.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Methods of randomisation were ambiguous. The guidelines of a randomised trial with the probability of samples method and stratified sampling were applied. A preliminary retrospective study was conducted. Authors also mentioned: "Patients were assigned in two groups (LCBDE vs ERCP). All patients had an informed consent for their randomisation. We had to take into account and the preference of the surgeon responsible for their treatment." The author is not contactable at the provided email address.
Allocation concealment (selection bias)	Unclear risk	Unclear.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible.
Selective reporting (reporting bias)	Low risk	Unclear.
Incomplete outcome data	Low risk	Unclear.
For‐profit bias	Low risk	Unclear.
Other bias	Low risk	Unclear.