Cohen 2008.

Methods	RCT
Participants	Johns Hopkins Medical Institutions, Maryland & Walter Reed Army Medical Center, Washington, DC, USA (N = 28) Inclusion criteria Older than 18 years Axial low back or buttock pain ≥ 6 months Tenderness overlying SI joint(s) Failure to respond to conservative therapy Long‐term (2 months) pain relief with SI joint corticosteroid injections Pain relief ≥ 75% as calculated from a 6‐hour post‐block pain diary after a single diagnostic SI joint injection Exclusion criteria Focal neurological signs or symptoms Radiological evidence of symptomatic herniated disc Spondyloarthropathy Untreated coagulopathy Unstable medical or psychiatric illness that might preclude an optimal treatment response
Interventions	Experiment group Cooled RF denervation group received L4–L5 primary dorsal rami and S1–S3 lateral branch RF denervation (80°C, 90 seconds) using cooling probe technology after local anaesthetic block (N = 14) Control  group Control group received local anaesthetic block followed by placebo denervation, in which 0.5 mL lidocaine 2% was administered with no current (N = 14) Participants who did not respond to placebo injections crossed over and were treated with RF denervation using conventional technology
Outcomes	Significant changes between groups for pain intensity (VAS) 1 and 3 months after treatment, and for function (ODI) 1 month after treatment Pain intensity: change in VAS score at 1 month: ‐3.7 (E), ‐0.2 (C) Pain intensity: change in VAS score at 3 months: ‐3.7 (E), ‐0.5 (C) Function: change in ODI score at 1 month: ‐16.2 (E), ‐4.3 (C) Function: change in ODI score at 3 months: ‐13.1 (E), ‐23.9 (C)
Notes	Dropouts: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random assignment in blocks of 4 via pre sealed envelopes
Allocation concealment (selection bias)	Low risk	Presealed envelopes
Blinding (performance bias and detection bias) All outcomes ‐ patients?	High risk	Blinding evaluated shortly after conclusion of the procedure, when effects of local anaesthetic were still active
Blinding (performance bias and detection bias) All outcomes ‐ providers?	High risk	Participants treated with placebo after 1 month
Blinding (performance bias and detection bias) All outcomes ‐ outcome assessors?	High risk	Participant‐reported outcome measures. Participants who did not show adequate symptomatic improvement were unblinded at follow‐up. For those who reported significant relief 1 month after the procedure, unblinding was done 3 months after treatment
Incomplete outcome data (attrition bias) All outcomes ‐ drop‐outs?	Low risk	No dropouts; only 3 placebo participants refused to cross over
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis?	High risk	Cross‐over procedure
Selective reporting (reporting bias)	Unclear risk	No protocol available
Baseline characteristics similar?	High risk	Meaningful differences in morphine use and function
Co‐interventions avoided or similar?	Unclear risk	Remained unclear from text
Compliance acceptable?	Low risk	Irrelevant: single‐session intervention
Timing of outcome assessments similar?	Low risk	Similar until 3‐month follow‐up