Lugli 2010.

Methods	RCT Approved by the ethics committee and written informed consent obtained Setting: Canada Funding: governmental
Participants	24 patients undergoing elective colorectal surgery Exclusion criteria were severe cardiac, hepatic, renal or metabolic disorders; diabetes mellitus type 1 with plasma albumin concentration < 35 g/L; more than 10% weight loss during the preceding 3 months; anaemia (haematocrit level < 30%); use of steroids; previous spine surgery limiting use of an epidural catheter; and pregnancy
Interventions	Treatment group: thoracic (T8‐T10) epidural analgesia with 0.5% bupivacaine for a sensory level from T4 to S1, maintained with an infusion of 0.25% bupivacaine during surgery and 0.1% bupivacaine plus fentanyl 3 mcg/mL for 48 hours after surgery (n = 12) Control group: IV patient‐controlled analgesia with morphine (n = 12)
Outcomes	Pain: Pain scores at rest, at 12 and 24 hours after surgery and during the study on the second postoperative day never exceeded the value of 4, and no participant in either group reported severe pain
Notes	Data not extractable enough. Study authors contacted; replied on 4 May 2015, that they would send the data but never did so
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"randomly allocated by a computer‐generated schedule" and "stratified for presence/absence of diabetes type 2"
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	No loss to follow‐up
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced