Methods	Randomised, double blind, active control Radiofrequency lesioning carried out at 80°C for 90 s at each site; phenol ablation carried out with 7% phenol. For both procedures, radiofrequency cannula was positioned, with stimulation at 50 and 2 Hz to identify proximity to sensory and motor nerves, and maintain blinding. Participants remained in prone position for 30 minutes Participants monitored on ward for 24 hours. Follow up at 1 and 7 days, and 2 and 4 months
Participants	Complex regional pain syndrome. History of failure to respond (pain intensity >6/10) to treatment with oral pregabalin, amitriptyline, carbamazepine over >6 months, and response (pain intensity < 4/10) after diagnostic sympathetic block with lidocaine on three occasions N = 20 M/F not reported Mean age 52 years in radiofrequency group, 39 years in phenol group
Interventions	Radiofrequency lumbar sympathectomy, n = 10 Phenol lumbar sympathectomy, n = 10
Outcomes	Nine pain outcomes, each assessed on a 0-10 scale Adverse events Withdrawals
Notes	Oxford Quality Score: R = 2, DB = 2, W = 1; Total = 5/5 Oxford Pain Validity Score: 13/16
Risk of bias
Bias	Authors’ judgement	Support for judgement
Adequate sequence generation?	Low risk	“computer-generated” random numbers
Allocation concealment?	Unclear risk	Not reported
Blinding? All outcomes	Low risk	Patients blinded by creating similar scene for both procedures. Investigator collecting data not involved in procedures and unaware ofthe group to which patients were assigned

DB - double blinding; N - number of participants in study; n - number of participants in treatment group; R - randomisation; W - withdrawals