Sahin 2013

Methods	Randomized controlled trial Approved by the ethics committee; informed parental written consents obtained ACTRN12611000585921 (7/06/2011) from Australian New Zealand Clinical Trials Registry Setting: university hospital, Turkey Funding: none declared Date of collection: December 2010 through May 2011
Participants	57 ASA 1 or 2 children between 2 and 8 years of age undergoing unilateral inguinal hernia repair Exclusion criteria included psychiatric illness, kidney failure and known hypersensitivity to relevant drugs
Interventions	Treatment group: transversus abdominis plane block with ultrasound (real‐time; in‐plane) and 0.5 mL/kg of 0.25% levobupivacaine. The block was performed after anaesthesia induction with a 10 to 18 mHz probe placed between the iliac crest and the subcostal area at the mid‐axillary line and the needle directed posteriorly. The surgical procedure began 5 to 10 minutes after local anaesthetic administration (n = 29) Control group: wound infiltration with 0.2 mL/kg of 0.25% levobupivacaine between external aponeurosis and the skin was performed by surgeons during wound closure (n = 28) In both groups, rectal paracetamol 40 mg/kg was administered as a loading dose after induction of anaesthesia
Outcomes	Block duration
Notes	Pain in PACU: Pain scores were assessed by using the modified Children’s Hospital of Eastern Ontario Pain Scale. Data were not included in the report. We contacted the study authors twice (26 January 2015 and 14 February 2015) but received no reply from them
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Patients were randomised by sealed envelopes"
Allocation concealment (selection bias)	Low risk	"Patients were randomised by sealed envelopes"
Blinding of participants and personnel	Unclear risk	Blinding or masking began in the recovery room
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding or masking began in the recovery room. The recovery room nurse assigned to each participant was blinded to study groups
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 participants lost to follow‐up: 1 in ultrasound group and 2 in infiltration group
Selective reporting (reporting bias)	High risk	Not intention‐to‐treat
Other bias	Unclear risk	Higher volume of local anaesthetic in the ultrasound group. Blocks performed after anaesthesia induction for the ultrasound group and during wound closure for the infiltration group