Boylan 1998.

Methods	RCT Approved by the ethics committee and written informed consent obtained Setting: Canada Funding: governmental
Participants	40 ASA 2 or 3 patients coming for elective open aorto‐bifemoral bypass
Interventions	Treatment group: LEA at L2‐L3 or L3‐L4 with bupivacaine 0.125% and morphine 0.1 mg/mL for 48 hours (n = 19) Control group: IV PCA with morphine for 48 hours (n = 21) General anaesthesia for all participants
Outcomes	VAS scores at rest at 8, 24 and 48 hours VAS scores on movement at 8, 24 and 48 hours
Notes	Study authors contacted for additional information on 18 July 2014; replied that original data were no longer available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomly assigned", no details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	High risk	"Opened design"
Blinding of outcome assessment (detection bias) All outcomes	High risk	"Opened design"
Incomplete outcome data (attrition bias) All outcomes	Low risk	No failed epidural mentioned
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced In intention‐to‐treat