Freitas 2013.

Study characteristics
Methods	RCT parallel
Participants	N = 40 (though adverse event reporting implies 20 and no CONSORT flowchart presented). Presume 20 per group. Age: not reported Sex: not reported Lower limb CRPS‐I. Diagnostic criteria: IASP Bruehl 1999 Duration of pain prior to block: > 6 months Type of initiating injury: not reported Concomitant treatments: not reported Medico‐legal factors: excluded if pending litigation Previous treatment: unresponsive to medication and physiotherapy (such as oral gabapentin 2400 mg/d, oral amitriptyline 100 mg/d, and oral carbamazepine 1000 mg/d and physiotherapy for more than 6 months
Interventions	Group 1: LASB lumbar plexus sympathetic block L2‐3 and L3‐4. 15 ml lidocaine and 100 mcg clonidine at each level Group 2. Pulsed radiofrequency (PRF) lumbar plexus L2‐3 and L3‐4, x3 120sec cycles at each level at 42º C. 1 ml of 2% lidocaine injected at each level Evaluation of technical adequacy of blocks: no Number of blocks: 1 per site, on 1 occasion Concomitant treatments: not reported
Outcomes	Pain intensity VAS, neuropathic pain scale. No numerical data provided. SF‐36. Means reported but no measures of variance Statistically significant difference seen in "hot pain" at "final score" but this time point is not clearly defined ‐ likely 6 months. Adverse events: "2 out of 10" had paraesthesia following PRF. "1 out of 10" had paraesthesia following LASB. Note; this implies 20 rather than 40 participants.
Country of origin	Brazil
Study aim	To determine whether percutaneous PRF applied directly to the sympathetic lumbar plexus was more effective than lumbar sympathetic blocks, and, if so, whether this could be achieved without the risks associated with traditional ablative procedures
Notes	Conflicts of interest not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were randomized to either PRF or sympathetic lumbar block according to computer generated random numbers"
Allocation concealment (selection bias)	Unclear risk	Comment: no information given
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: Personnel not blinded however, comparison is between two active invasive interventions.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: Participants blinded to group assignment
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1 participant in pulsed radiofrequency group dropped out ‐ reasons unclear and unclear whether data missing or excluded
Selective reporting (reporting bias)	High risk	Pain outcome data are not reported in numerical format
Adequate sample size?	High risk	N = 40 entered the study but reporting of adverse events suggests 20 participants
Adequate duration of follow‐up?	Low risk	6‐month follow‐up
Free of other bias?	Unclear risk	No baseline data presented; no detail given regarding concomitant treatments