Medical treatment for sacroiliac joint (SIJ) pain has been less than successful. Doctors have tried injecting the joint with a numbing agent and even fusing the joint in severe cases. A new treatment under investigation may change that. New water-cooled radiofrequency technology has been shown very effective in preliminary studies.
The research is being done at the well-known Johns Hopkins School of Medicine in Baltimore. The first study in a series compared two groups of patients. The first group was the treatment group. The second group was the control group. They all received one injection of a numbing agent directly into the SIJ. This type of nerve block has been used to diagnose and treat SIJ in the past.
Then for the treatment group, the surgeon used a radiofrequency probe to cut sensory nerves to the SIJ. The procedure is called denervation. The control group had a placebo denervation. Results were compared between the two groups. Measures of effectiveness included pain relief and improved function. Patients had to have more than 50 per cent improvement in both areas. Otherwise, a less than 50 per cent improvement would be no better than chance if they did or did not improve.
The treatment group had major improvements in all areas compared with the placebo group. And a significant number of patients in the treatment group still had positive benefits six months later. Results in the placebo group only lasted 30-days.
The short-term effects observed are typical in a placebo group. The patients think they had a beneficial treatment. They respond favorably (mind over matter), but the results don’t necessarily last because nothing was really done to change the problem.
This first study was just a start. It’s not really a treatment everyone will try just yet. Because it was done with a small number of patients (28 total), a second study is needed to prove the results weren’t just a fluke. The second study (by the same researchers at Johns Hopkins) with 150 patients is underway.
Besides showing the benefit of this treatment, the authors will also try to narrow down which patients are most likely to respond to radiofrequency denervation for their SIJ pain. One way to sort this out is to divide the study into three groups: 1) radiofrequency denervation without a nerve block, 2) radiofrequency denervation after one block injection, and 3) radiofrequency denervation after two nerve blocks.
The reason for using three different groups is safety and effectiveness. If a patient responds well to a single nerve block and no further treatment is needed, then there’s no point in cutting the nerve. Likewise, there may be patients who respond well to the nerve block after two blocks. The goal is to find out which patients truly need a denervation procedure.
The authors believe that with a tight selection criteria, this new technology will benefit a specific subgroup of individuals who suffer from chronic sacroiliac joint pain. Clearly, the first study showed that the treatment is not a sham. Refining the treatment is the next step before this approach might be available for use in the general population.