Researchers have found 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 of the lateral branches in patients suffering with low back pain. The study was presented by Jianguo Cheng, professor of Anesthesiology and programme director, Cleveland Clinic Pain Medicine Fellowship Program, Departments of Pain Management and Neurosciences, USA, at the American Academy of Pain Medicine’s 28th Annual Meeting (Palm Springs, California, 23–26 February 2012)
“The major barrier to treat this pain effectively is that we do not 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,” said Cheng.
One of the modalities often used to relieve low back pain has been the sacroiliac joint 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.
Radiofrequency ablation of the lateral branches is often considered if the patient has had more than 50% pain reduction from the sacroiliac joint 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% or more pain relief from the sacroiliac joint steroid injection. We are seeing more and more insurers deny this treatment option because they did not meet these criteria,” commented Cheng.
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 sacroiliac joint injection, with 60 patients reporting greater than 50 % relief, and the remaining 20 patients reporting 25 – 49% 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-radiofrequency ablation 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% from a sacroiliac joint intraarticular steroid injection does not predict the outcomes of radiofrequency ablation of the lateral branches. The duration of pain relief post-radiofrequency ablation of the lateral branches is independent of the degree of pain relief within the range of 25 – 100% after sacroiliac joint intraarticular steroid injection.
“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 radiofrequency ablation, there are not many other alternatives, and many people end up on chronic opioids, which often create other possible opioid-related problems,” Cheng concluded.
