Thermal versus cooled radiofrequency in patients with sacroiliac joint pain: a systematic review of the literature and pooled analysis of clinical outcomes

Chronic low back pain (LBP) can be caused by sacroiliac joint (SIJ) disease. Many conditions could cause SIJ dysfunction. The lateral branches of the L4-S3 dorsal rami are responsible for the primary innervation of the posterior SI joint. Radiofrequency (RF) denervation represent an emerging promising treatment for refractory sacroiliac joint pain. There are different types of RF denervation such as thermal or cooled. Use of irrigation cooled electrodes allows targeted tissues to reach the neuroablative temperatures slowly, preventing collateral damage of adjacent tissue.We conducted electronic database (PubMed, Medline, Cochrane and Google Scholar) research (time frame: January 1st, 2010 to May 31st, 2021) for clinical studies that had tested conventional radiofrequency (RFT) and cooled radiofrequency (RFC) to treat sacroiliac joint pain. These studies were evaluated according to Level of Evidence. Quantitative assessment of qualifying studies was done using the random effects model. We calculated the pooled size effect using standardized mean difference (SMD) as the main effect measure.We identified nine studies, with a total of 276 patients affected by sacroiliac joint pain and treated with radiofrequency. The analysis revealed a small and non-significant difference in pain reduction and an improvement in quality of life in RFT subgroup (Pain measured in Visual Analogic Scale: RFT subgroups SMD=-3.643 (95% CI -4.478, -2.807), RFC subgroup SMD=-3.285 (95% CI -4.428, -2.141), P=0.587; Quality of Life measured in Oswestry Disability Index: RFT subgroup SMD=-35.969 (95% CI -53.993%, -17.945%), RFC subgroup SMD=-20.589% (95% CI -33.424%. -7.754%), P=0.123). Publication bias was found in quality-of-life assessment due to the low number and high heterogeneity of studies. Two techniques showed no major complications.Current evidence indicates no statistical difference between two techniques examined. The literature is currently lacking, and well-constructed randomized clinical trials are necessary to evaluate this deficient aspect.