Zhang 2003.

Methods	Randomized controlled trial (4 arms)
Participants	Adults undergoing elective craniotomy (n = 60) Inclusion criteria ASA I to III participants undergoing elective supratentorial craniotomy Exclusion criteria None reported Mean age, range (years) 44 (18 to 70) Numbers allocated to each arm Group 1: control: 10 Group 2: scalp block: 17 Group 3: wound infiltration: 17 Group 4: superficial cervical plexus block: 16 Male gender Not reported
Interventions	Technique and timing Regional infiltration or block 0.75% ropivacaine at the end of surgery Dosages Unclear from report
Outcomes	Primary Pain as measured by the visual analogue score (VAS) during the first 48 hours after surgery Secondary None
Notes	Paper only available in Chinese so some translation errors possible Funding None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not reported
Allocation concealment (selection bias)	High risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	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 reported as specified
Other bias	High risk	Small study and analysis method not completely described