Researchers from Cleveland Clinic report at the American Academy of Pain Medicine's 28th Annual Meeting that there is no evidence that the degree of pain relief from intraarticular steroid injections of the sacroiliac joint predicts the outcome of radiofrequency ablation (RFA) of the lateral branches in patients suffering with low back pain.

The study was presented by Jianguo Cheng, MD, PhD, Professor of Anesthesiology and programme director, Cleveland Clinic Pain Medicine Fellowship Programme, Departments of Pain Management and Neurosciences.

Spinal pain is a significant problem in the United States and sacroiliac joint (SIJ) pain is a challenging condition affecting 13 - 30 per cent of patients with axial low back pain. “The major barrier to treat this pain effectively is that we don't have a good understanding of the pain and its mechanism, and therefore many different modalities of treatment have been tried in the last 50 years, but none of them have been quite successful,” comments Dr Cheng.

One of the modalities often used to relieve low back pain has been the sacroiliac joint (SIJ) intraarticular steroid injection, which is both diagnostic and pain relieving. The length of time the procedure provides pain relief varies greatly and may not be an effective long-term option for many patients. However, the degree of pain relief from intraarticular steroid injections is often used to determine if the patient is a good candidate for radiofrequency ablation (RFA).

Radiofrequency ablation of the lateral branches is often considered if the patient has had more than 50 per cent pain reduction from the SIJ intraarticular steroid injection, which may provide better pain relief and for longer periods of time. Researchers aimed to determine if the degree of pain relief after a sacroiliac joint steroid injection is predictive of the duration of pain relief after radiofrequency ablation of the lateral branches. “We believe that patients who may have relatively good pain relief with radiofrequency ablation are often excluded from this modality because they do not meet the criteria of 50 percent or more pain relief from the SIJ steroid injection. We are seeing more and more insurers deny this treatment option because they didn't meet this criteria,” Dr Cheng states.

After Institutional Review Board approval, the researchers collected data from 80 patients undergoing radiofrequency ablation. The patients were grouped according to the degree of pain relief as a result of their previous SIJ injection, with 60 patients reporting greater than 50 percent relief, and the remaining 20 patients reporting 25 - 49 percent pain relief. After adjusting for variables such as age, modes of pain onset, multiple pain complaints, and responses to extension or axial rotation of the lumbar spine in the multivariable proportional hazards model, the difference in duration of post-RFA pain relief between the groups was insignificant (p = 0.91, hazard ratio [95% confidence interval] of 0.96 [0.49, 1.90]).

The researchers concluded that the degree of pain relief within the range of 25 – 100 percent from a sacroiliac joint intraarticular steroid injection (SISI) does not predict the outcomes of radiofrequency ablation of the lateral branches. The duration of pain relief post-RFA of the lateral branches is independent of the degree of pain relief within the range of 25 – 100 percent after SISI.

“This study provides another piece of evidence to support our practice of pain medicine, to help guide patient selection, and to improve clinical outcomes. For many who are denied RFA, there are not many other alternatives, and many people end up on chronic opioids, which often create other possible opioid-related problems,” Dr Cheng concludes.

The American Academy of Pain Medicine is the premiere association for 2,400 pain physicians and their treatment teams. Its mission is to optimize the health of patients in pain and eliminate it as a major public health problem by advancing the practice in the specialty of pain medicine.