Seidel 2013.

Methods	Randomized, parallel design
Participants	250 ASA I ‐ III adult patients scheduled for orthopaedic foot surgery under tourniquet Exclusion criteria not given
Interventions	Ultrasound (n = 125) versus nerve stimulation (n = 125); Distal sciatic block of sciatic, tibial and common peroneal nerves; each nerve blocked with 20 ml 1% prilocaine and 10 ml 0.75% ropivacaine Ultrasound: 6 ‐ 13 MHz linear probe (Sonosite); intraepineural needle position Nerve stimulation (Stimuplex): 0.1 msec duration, frequency 2 Hz; starting current 1.0 mA
Outcomes	Block requiring supplementation or conversion to GA Block onset time
Notes	Saphenous nerve block for tourniquet pain given to all participants Registered in clinicaltrials.gov Data for block onset time presented as log‐rank test results and therefore not possible to combine for this review Reported as significantly shorter onset time in US group, P value < 0.01
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated list
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation	High risk	Not possible to blind anaesthetist
Blinding of participants and personnel (performance bias): time outcomes	High risk	Not possible to blind anaesthetist
Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block	Low risk	Observer blinded from group allocation
Blinding of outcome assessment (detection bias): time outcomes	Low risk	Observer blinded from group allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	7 participants in each group excluded from analysis, but low attrition rate
Selective reporting (reporting bias)	Low risk	Protocol details published in clinicaltrials.gov. NCT 01643616. Outcomes appear to be reported
Baseline characteristics	Low risk	Age, weight, height, gender, surgery time, diabetes mellitis. Some difference in gender balance but otherwise all comparable
Funding sources	Low risk	No conflicts of interest or funding declared
Operator expertise	Unclear risk	No details