PALM SPRINGS, CALIF. – The degree of sacroiliac joint pain relief provided by intra-articular steroid injection of the sacroiliac joint did not predict the duration of pain relief from subsequent radiofrequency ablation of the lateral branches that innervate the sacroiliac joint, judging from findings from a retrospective study of 80 patients.
Based on these results, patients who get only 25%-49% relief of pain from steroid injection of the sacroiliac joint (SISI) should not be disqualified from undergoing radiofrequency ablation of the lateral branches, Dr. Jianguo Cheng and his associates suggested in an award-winning poster and plenary presentation at the annual meeting of the American Academy of Pain Medicine.
Dr. Jianguo Cheng
The study retrospectively collected data on 87 patients undergoing radiofrequency ablation of the lateral branches who’d had a preoperative SISI between January 2006 and June 2009 at The Cleveland Clinic. The seven patients who were missing follow-up data were excluded from the final analysis.
In all, 60 of the 80 patients in the analysis reported at least 50% pain relief as a result of SISI (75%) and 20 patients reported less than 50% pain relief (25%). After radiofrequency ablation of the lateral branches, approximately 50% of all patients reported at least a 50% reduction in pain. The degree of pain relief from radiofrequency ablation did not differ significantly at follow-up visits 1, 3, 6, and 12 months between patients who had experienced 25%-49% pain relief after SISI and patients who reported 50% or greater pain relief after SISI, said Dr. Cheng, who is professor of anesthesiology and program director of pain medicine fellowship program of Cleveland Clinic Foundation.
The analysis adjusted for the effects of potential confounders. Patients who had experienced less than 50% pain relief after SISI were significantly younger than those with at least 50% pain relief after SISI (a mean of 52 years vs. 59 years) and significantly less likely to have had gradual onset of their chronic back pain (60% vs. 82%) and more likely to have had pain with extension or axial rotation (80% vs. 52%). Other characteristics did not differ between groups.
Although the efficacy of radiofrequency ablation of the lateral branches at 3 months was comparable to reports in the literature, the efficacy after 6 months was lower in the study compared with previous reports. Approximately 40% of patients in the study had at least a 50% reduction in pain 6 months after radiofrequency ablation compared with 52%-57% in published reports, Dr. Cheng said. This difference may be due to the older age of patients in the current study compared with previous ones (58 vs. 52 years on average), a higher rate of previous spine surgery (30% vs. 21%), and greater likelihood of multiple pain complaints and opioid use in the current cohort (70% vs. 46%), he suggested.
The current study is larger than most previous ones but is limited by its retrospective design, Dr. Cheng said.
In general, 16%-30% of cases of chronic lower back pain can be attributed to sacroiliac joint pain. Radiofrequency ablation of the lateral branches has emerged as a promising modality in recent years while other treatment modalities have provided mixed and often disappointing results, including pharmacotherapy, viscosupplementation, prolotherapy, chiropractic manipulation, intra-articular injections, and surgical fixation, he said. The findings of the current study should help inform pain interventionists in deciding who is a candidate for radiofrequency ablation.
Dr. Cheng reported having no financial disclosures.