Levy 2011.

Methods	RCT Approved by the ethics committee and consent obtained Registration number: NCT 18926278 Setting: United Kingdom Funding: departmental
Participants	Patients with colorectal disease (benign or malignant) who required a laparoscopic large bowel resection that did not involve a stoma or perineal dissection were considered for the trial
Interventions	Treatment group: TEA (T9‐T12) with bupivacaine 0.15% and fentanyl 2 mcg/mL for 48 hours (n = 30) Control group: IV PCA with morphine (n = 30) General anaesthesia for all participants
Outcomes	Time to first faeces VAS scores on movement/coughing (whichever worst), evening (taken as 6 to 8 hours), 24 hours Leak Hospital LOS (from the start of surgery)
Notes	Study also includes a group with spinal analgesia, not retained in our analysis Study authors contacted for additional information on 21 July 2014, but did not reply
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization code was created by an independent company, which used a computer randomization programme to generate the sequence, then placed the appropriate analgesic regimen in sequentially numbered opaque envelopes
Allocation concealment (selection bias)	Low risk	The randomization code, which was kept in an opaque envelope in an off‐site building, was opened after consent was obtained
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	99 included and 91 completed the trial
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Unclear risk	Groups well balanced except higher body weight for the opioids group Not in intention‐to‐treat