Van Geffen 2009.

Methods	RCT, parallel design
Participants	40 ASA I ‐ III patients undergoing surgery of foot or ankle with distal sciatic nerve block in popliteal fossa Exclusion criteria: Patient refusal, pre‐existing neuropathy, kidney or liver disease, pregnancy, skin infection at site of needle insertion and inability to communicate
Interventions	Ultrasound (n = 20) versus nerve stimulation (n = 20) Distal sciatic nerve block in the popliteal fossa with lignocaine 1.5% with adrenaline 5 µg/ml – at discretion of anaesthetist, min of 25 ml and max of 40 ml Ultrasound: with 7 ‐ 13 MHz 38 mm linear probe (Sonosite); endpoint ‐ visualization of LA distribution around nerve Nerve stimulation (HNS 11, Braun): 0.1 msec duration, frequency 2 Hz; starting current 1.0 mA. Initial current reduced until responses maintained with minimum of 0.2 mA and max 0.5 mA
Outcomes	Adequacy of block (defined as "surgical block success") Block performance time (interval between first needle insertion and its removal at end of injection of local anaesthetic) Number of attempts Pain during puncture
Notes	Anaesthetists had extensive clinical experience with nerve stimulation guided popliteal sciatic nerve blocks but no experience with ultrasound guidance block Some participants also given saphenous nerve block if tourniquet required for surgery; no details in results of those that were given additional block
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomized using sealed envelopes. No further detail
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation	High risk	Anaesthestists not blinded
Blinding of participants and personnel (performance bias): time outcomes	High risk	Anaesthestists not blinded
Blinding of participants and personnel (performance bias): Patient discomfort	High risk	Anaesthestists not blinded
Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block	Unclear risk	No details of who assessed this. Assume anaesthetist?
Blinding of outcome assessment (detection bias): time outcomes	Low risk	Assessor blinded to block technique
Blinding of outcome assessment (detection bias): Patient discomfort	Low risk	Assessor blinded to block technique
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	Published protocol not sought
Baseline characteristics	Low risk	Age, weight, height, ASAI‐III, gender, type of surgery. All comparable
Funding sources	High risk	Funding from dept sources. Study equipment supported was provided from Sonosite Inc, Bothell, WA, USA
Operator expertise	High risk	Anaesthetists had extensive clinical experience with nerve stimulation guided popliteal sciatic nerve blocks but no experience with ultrasound guidance block