Kern 2012.

Study characteristics
Methods	Study design: prospective randomised trial Method of randomisation: computer‐generated random table Blinding: participants ‐ yes, doctor ‐ no, outcome assessor ‐ no Power calculation: were required to detect a true difference of half of a standard deviation at a 1‐sided 5% significance level with a power of 80% Total number of participants: 53 Total number of procedures: 106 Treatment localisation: leg veins Number of exclusions post‐randomisation: none Number of withdrawals and reasons: none
Participants	Setting: outpatient site Country: Switzerland Gender: women Age: 49 mean age (range 29 ‐ 74) Inclusion criteria: women were eligible if presenting for cosmetic reasons for sclerotherapy of reticular and telangiectatic leg veins (C1A or S). Distribution of telangiectasias and reticular leg veins had to be similar in both legs. Participants had no signs of superficial or deep vein insufficiency as assessed using duplex ultrasound Exclusion criteria: allergies to chrome and to lidocaine‐epinephrine No patient declined participation, and there were no patient‐reported allergies, so no patient was excluded from the study
Interventions	Treatment 1: standard treatment technique (successive injections of chromated glycerin mixed with one‐third lidocaine‐epinephrine 1%) Treatment 2: new 2‐step technique (first treating only reticular veins with a single injection at the base of each cluster of telangiectasias and then successively injecting all remaining telangiectasias a few minutes later) Both legs were treated during the same sclerotherapy session. One lower limb underwent standard treatment technique, the other one underwent the new 2‐step technique. Reticular vein diameter ranged between 1 and 2 mm and that of telangiectasias between 0.2 and 1 mm Duration of follow‐up: 3 weeks Use of compression: compression stocking
Outcomes	The main study outcome was participant pain score. Immediately after each leg treatment, participants were asked to score their pain using a 100‐point visual analogue scale (0 = no pain, 100 = maximal pain). Participants graded their pain by drawing a line on the scale. At the end of the session, participants were asked to indicate on which leg injections were more comfortable
Funding sources	No details provided
Declarations of interest	None declared
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Before treatment, each participant was randomly assigned (computer‐generated random table) to receive the standard technique or the 2‐step technique first
Allocation concealment (selection bias)	Unclear risk	No details given
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants were blinded to the randomisation and did not know which technique was going to be performed first
Blinding of outcome assessment (detection bias) All outcomes	High risk	Immediately after each leg treatment, participants were asked to score their pain using a 100‐point VAS (0 = no pain, 100 = maximal pain). Participants graded their pain by drawing a line on the scale. At the end of the session, participants were asked to indicate on which leg injections were more comfortable
Incomplete outcome data (attrition bias) All outcomes	Low risk	53 participants were randomised, so there were 53 legs in the standard technique group and 53 legs in the 2‐steps technique group
Selective reporting (reporting bias)	Unclear risk	No details given
Other bias	Unclear risk	No details given