Thorén 1989.

Methods	RCT Approved by the ethics committee and written informed consent obtained Setting: Sweden Funding: governmental
Participants	22 ASA 1 or 2 female patients undergoing hysterectomy
Interventions	Treatment group: TEA (T12‐L1 with the catheter inserted 2 to 3 cm into the epidural space) with bupivacaine 0.5% during surgery, and 0.25% 8 mL/h for 42 hours (n = 11) Control group: TEA (T12‐L1 with the catheter inserted 2 to 3 cm into the epidural space) with morphine 4 mg bolus, 2 mg on request for 42 hours (n = 11) All participants operated under general anaesthesia
Outcomes	Time to first flatus (hours) Time to first faeces (hours) VAS scores at day 1 (taken as at rest) Length of hospital stay (days)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Before operation, participants were randomly allocated to 2 groups
Allocation concealment (selection bias)	Unclear risk	Before operation, participants were randomly allocated to 2 groups
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced