Cokay 2013.

Methods	Study design: randomized controlled trial (2 arms) Study duration: not reported Study setting: hospital, single centre, Turkey
Participants	Adults undergoing elective craniotomy (n = 60) Inclusion criteria ASA I to ASA III participants Exclusion criteria Not specified Mean age, range (years) 49 (18 to 80) Numbers allocated to each arm Not reported Male gender Not reported
Interventions	Technique and timing Scalp block with 2.5% bupivacaine versus scalp block with saline before surgery, specific nerves blocked were not reported Dosage 20 mL
Outcomes	Primary Haemodynamic parameters (no specific details provided) Secondary Pain as measured by the visual analogue score Time to requirement of rescue analgesia Total amount of rescue analgesia required
Notes	Published in abstract format only Paper published in abstract format only so many details not reported Funding None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Reported as randomized but method used was not reported
Allocation concealment (selection bias)	High risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Reported as double‐blinded but method or adequacy not reported
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	High risk	Not reported
Selective reporting (reporting bias)	Low risk	Outcomes were reported as specified.
Other bias	High risk	A lot of data missing so difficult to determine overall methodologic rigour