Micha 2012.

Methods	Double‐blinded (participant/outcome assessor), placebo‐controlled, randomized clinical trial Sequence generation by computer‐generated random numbers Follow‐up: 6 months
Participants	Participants: 35 adults in a hospital setting, Athens, Greece Operation: modified radical mastectomy with axillary dissection Groups, size: 17/18 Age: not specified All female participants, 13/7 Comorbidities: none included
Interventions	Group 1 (ropivacaine): intra‐op: infiltration before wound closure with 10 mL ropivacaine 7.5 mg/mL. 3 mL of the solution was infiltrated around the route sheath of brachial plexus and the rest of it in the 1st‐7th intercostal spaces. Group 2 (saline): intra‐op: same method as above with infiltration of saline Adjuvants: none Immediate post‐op pain control: no difference
Outcomes	Dichotomus: pain questionnaire at 6 months Continuous: none Other reported: none Adverse events: none reported
Notes	Funding sources: no explanation of financial support Conflicts of interest: conflict of interest statement was not provided
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Response from study author: "Randomisation was done by means of a computer generated table"
Allocation concealment (selection bias)	Low risk	Response from study author: "Mrs Vassi was the only person throughout the study period that was aware of the allocation group. She didn’t participate in any other part of the study pre‐ or postoperatively nor did she have any contact with the patients at any time."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Response from study author: "The anaesthesiologists in the operating room were unaware of the allocation group and so was the surgeon." The participants were also unaware of their group allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Response from study author: "...the record of the pain medicines administered and the telephone contact 6 months postoperatively were performed by me, who I was unaware of the study group throughout the study period."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "thirty‐five patients were enrolled in the study and six of them were excluded (failure to be contacted by phone)."
Selective reporting (reporting bias)	Low risk	No subgroup analysis or selective reporting was noted
Null bias	High risk	Quote: "no difference was documented...in chronic neuropathic pain." "Ropivacaine infiltration does not seem to attenuate chronic neuropathic pain...after modified radical mastectomy."