Evidence suggests that radiofrequency ablation (RFA) of the sacral lateral branches may provide relief for pain that originates from the posterior sacroiliac joint complex, according to a narrative review published in PM&R.
However, the researchers noted that current evidence is limited by variability in patient selection criteria, the nature of the nerves targeted for ablation, and the types/techniques of RFA technology used.
The researchers searched PubMed and Google Scholar through June 2018 for publications in which the use of sacral lateral branch blocks (SLBB) was examined for the diagnosis of sacroiliac pain and the effectiveness of sacral lateral branch RFA (SLBRFA) for treatment of sacroiliac joint (SIJ) pain was investigated. They identified 32 studies of SLBRFA for the treatment of posterior sacroiliac complex pain, including 4 explanatory clinical trials, 4 pragmatic clinical trials, and 24 observational studies. Of the 24 observational studies, 16 and 8 were retrospective and prospective studies, respectively.
Treatment targets varied across studies, from the L4 medial branch nerve and/or L5 dorsal ramus, to the sacral lateral branches, and the articular portion of the joint. In addition, the studies used a range of RFA technologies, including conventional monopolar RFA, conventional bipolar RFA, and cooled RFA. Most studies used fluoroscopic guidance, but two studies used computed tomography guidance and another used endoscopy.
In 1 explanatory randomized controlled study, cooled RFA was compared with sham treatment. At 3 months, 12% of participants in the sham group reported >50% relief of their index pain compared with 47% in the RFA group (P =.01). In another study that also compared cooled RFA and sham treatment, 79% of patients in the RFA group reported >50% relief of index pain compared with 14% in the sham group (P ≤.01).
In a pragmatic randomized controlled study, participants were randomly assigned to receive monopolar conventional RFA or intra-articular corticosteroid injection using fluoroscopic guidance. At 1 month, 20% of participants administered corticosteroids reported >50% reduction in index pain. In participants treated with RFA, 73%, 60%, and 53% reported >50% reduction of index pain at 1, 3, and 6 months, respectively.
In another pragmatic randomized controlled study, participants with low back pain underwent RFA plus a standardized exercise program or a standardized exercise program alone. The minimal clinically important difference was defined as a numeric pain scale improvement of ≥2 points or >30%. A total of 41% of participants in the RFA group achieved success compared with 26% of patients in the exercise-only group.
“Explanatory (sham-controlled) clinical trials on SLBRFA using rigorous selection criteria such as dual multisite, multi-depth blocks are clearly needed to ascertain the true value of this procedure,” noted the researchers.
Yang AJ, McCormick ZL, Zheng PZ, et al. Radiofrequency ablation for posterior sacroiliac joint complex pain: a narrative review. [published online June 6, 2019]. PM R. doi:10.1002/pmrj.12200