Vrooman 2015

Methods	Triple‐blinded (participant, provider, outcome assessor), placebo‐controlled, randomized clinical trial Sequence generation by computer‐generated random numbers Follow‐up for 3 and 6 months
Participants	Participants: 78 adults in a university setting in USA Operation: robotic cardiac surgery 2 groups, size: 39/39 Age (± SD), group 1, 2: 56 (11), 58 (10) Men/women, group 1, 2: 31/8, 29/10 Exclusion criteria: history of severe psychiatric issues (e.g. depression, somatoform conversion disorder, and borderline personality disorder); addiction to alcohol, opioids, or illegal substances; known history of sensitivity to amide LAs; severe hepatic disease; or pregnant
Interventions	Group 1 (lidocaine): anaesthetic technique not described. The 5% lidocaine transdermal patches contained 700 mg of lidocaine. Each self‐adhesive patch was 10 cm x 14 cm. Up to 3 patches were applied to maximize analgesia while reducing the risk of systemic toxicity. Patches were applied for 12 h, removed for the subsequent 12 h, and then new patches were applied. This process was continued for 6 months or until participants no longer required analgesia. Additional postoperative analgesia was provided by participant‐controlled fentanyl (20 mg bolus, 6‐min lockout, no hourly limit). Morphine or hydromorphone was substituted in participants reporting sensitivity to fentanyl. PCA was continued for up to 3 days, with the exception of a single participant who was treated for 5 days, until participants could tolerate oral opioid medications such as oxycodone 5 mg to 10 mg every 4‐6 hours as needed. Participants who required more than 40 mg of oxycodone, or equivalent, per day were supplemented with fentanyl 25 mg/h transdermal patches Group 2 (control): same intervention as above except sham patches were used. Adjuvants: none Immediate post‐op pain control: no improvement
Outcomes	Dichotomous: none Continuous: VAS/VRS Secondary: VAS at POD 3; VRS at 1 week and 1 month, the Depression Anxiety Stress Score recorded the day before surgery, GPE‐a measure of participant satisfaction, recorded after 1 week, 1 month, 3 months, and 6 months. PDI at 3 and 6 months
Notes	Funding sources: funding for the study was provided by Endo Pharmaceuticals. Conflicts of interest: "none of the authors has a personal financial interest in this research."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomization was performed by our Research Pharmacy and was based on computer‐generated codes"
Allocation concealment (selection bias)	Unclear risk	Allocation of concealment was not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "all investigators and clinicians were fully blinded to treatment."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "incisional pain was evaluated over 6 months with data collected by an independent study coordinator who was blinded to treatment."
Incomplete outcome data (attrition bias) All outcomes	Low risk	There was no attrition and ITT analysis was performed
Selective reporting (reporting bias)	Low risk	No subgroup analysis was performed
Null bias	High risk	Quote: "lidocaine 5% patches did not influence any measure of acute or persistent incisional pain"