Breebaart 2003.

Methods	Randomization: yes Participant blinding: yes Provider blinding: yes Assessor blinding: yes Dropouts: 0
Participants	Country: Belgium ASA: I Gender: men and women Mean age (range): lido: 42 (20–57); levo: 39 (18–59); ropi: 39 (19–57) years Ambulatory surgery Surgical positioning: supine Number of participants: 90
Interventions	Drug 1: 2% lido, isobaric, fixed dose (3 mL) Drug 2: 0.5% levo, isobaric, fixed dose (3 mL) Drug 3: 0.75% ropi, isobaric, fixed dose (3 mL) Needle: 27 G, pencil‐point
Outcomes	TNS at 2 days Urinary retention
Notes	Follow‐up duration: 2 days Follow‐up method: telephone contact TNS therapy: none TNS resolution: 1 day
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote "…randomised (by a computer‐generated randomisation sequence)…"
Allocation concealment (selection bias)	Unclear risk	Not described.
Participant blinding (performance bias and detection bias)	Low risk	Quote: "…double‐blind study."
Provider blinding (performance bias)	Low risk	Quote: "…double‐blind study." "All 3‐ml solutions were prepared in an adjacent space by a supervisor not involved in the subsequent evaluation of the study‐patient." Comment: we assume from this comment that the syringes were unlabelled.
Assessor blinding (detection bias)	Low risk	Quote: "All 3‐ml solutions were prepared in an adjacent space by a supervisor not involved in the subsequent evaluation of the study‐patient."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "ninety patients…were included…" "Two days after discharge, all patients were contacted by phone…" Comment: results reported for 90 participants.
Selective reporting (reporting bias)	Unclear risk	Study protocol not available.