Motamed 1998.

Methods	RCT Approved by the ethics committee and written informed consent obtained Setting: France Funding: unspecified
Participants	60 ASA 1 or 2 patients aged between 18 and 70 years undergoing midline or bi‐subcostal incision
Interventions	Treatment group: TEA (T9‐T11) with bupivacaine 0.25% and morphine 0.25 mg/mL started after surgery for 48 hours (n = 28) Control group: IV PCA with morphine (n = 29) General anaesthesia for all participants
Outcomes	VAS scores at rest at 8 and 24 hours VAS scores on movement at 8 and 24 hours
Notes	Additional information received from study authors
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomized", no details
Allocation concealment (selection bias)	Unclear risk	Not mentioned
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	Three participants excluded for severe desaturation
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Unclear risk	Groups well balanced Participants in the epidural group who required supplemental analgesia were withdrawn from the study