Sacroiliac Steroid Injections Do Not Predict Ablation Relief

Kate Johnson

February 27, 2012

February 27, 2012 (Palm Springs, California) — One quarter of patients with chronic sacroiliac joint pain may be disqualified from receiving radiofrequency ablation (RFA) treatment based on inaccurate criteria for patient selection, a new study suggests.

Dr. Jianguo Cheng

The new report shows that response to intraarticular sacroiliac steroid injections (SISI), which is commonly used to predict a patient's response to RFA of lateral branches, was not an accurate predictor of their subsequent outcomes with this latter treatment, reported Jianguo Cheng, MD, PhD, from the Department of Neuroscience and the Department of Pain Management at the Cleveland Clinic in Ohio, here at the American Academy of Pain Medicine (AAPM) 28th Annual Meeting.

"Patients with less than 50% pain relief after SISI should not be disqualified" from receiving RFA, he concluded.

"It does fly in the face of what we typically do," commented session moderator James Watson, MD, from the Mayo Clinic in Rochester, Minnesota. "It suggests we don't have a very good predictor of who responds and who does not respond to radiofrequency ablation in the sacroiliac joint, which is a little bit surprising," he told Medscape Medical News.

Dr. Cheng's study was among the 6 highest-ranked papers presented here.

Predicting Response

In this analysis, the researchers retrospectively evaluated 80 patients who underwent RFA after SISI. "Our hypothesis was that patients with 50% or greater pain relief after SISI would have longer pain relief after RFA," Dr. Cheng said.

"For some patients it's easy: You give an intraarticular injection, and they get 8 months' pain relief, and there's no need for RFA," he said. However for other patients, the pain relief only lasts for 3 weeks. Because it is not possible to give an injection every 2 or 3 weeks, he added, "RFA is an option. But then the next question is...how do you predict the result of the RFA? And many insurance companies will not reimburse you for RFA if the patient does not reach 50% pain relief after SISI."

His study included post-RFA follow-up of greater or less than 50% patient-reported pain relief at 1, 3, 6, and 12 months.

Before RFA, 75% of patients reported 50% or greater pain relief after SISI. Patients who experienced better post-SISI relief tended to be older (59 vs 52 years; P = .04), were more likely to have gradual onset (82% vs 60%; P = .049), and were less likely to have pain with extension or axial rotation (52% vs 80%; P = .03).

After adjusting for characteristics significant for SISI-induced pain relief, the study showed that RFA pain relief was independent of SISI pain relief.

"We found no statistical evidence to support our hypothesis that post-RFA pain relief differed between patients who experienced 50% or greater pain relief from SISI and patients who experienced less than 50%" relief, he said.

"The degree of pain relief within the range of 25% to 100% from SISI does not predict the outcomes of RFA."

Asked to comment on the findings, Dr. Watson said the results are potentially practice-changing.

"His study was a retrospective study, and it will have to be confirmed and compared to a prospective study, but it raises the question of whether our approach is appropriate rationale, even if it's common practice," Dr. Watson told Medscape Medical News.

"Insurance companies often require that you meet a certain threshold of pain relief before they'll pay for the RFA," he added. "Medical societies want to apply the technology in a situation where it's likely to be of benefit. It's common practice. It's really the standard that's been used by most of the large, well-designed trials that have looked at RFA in the lumbar region."

Dr. Cheng and Dr. Watson have disclosed no relevant financial relationships.

American Academy of Pain Medicine (AAPM) 28th Annual Meeting: Abstract 136. Presented February 24, 2012.

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