There are nerve endings in all types of tissues. In the spine, they are present in the joints, discs, ligaments, and muscles. Because of this, finding the true source of back pain can be difficult.
In this study, researchers in Sweden measured the amount of nitric oxide (NO) in and around the facet (spinal) joints. This area is called the perifacetal region. They compared the results of patients with chronic low back pain to healthy adults with no back pain.
NO is a gas that acts as a signaling molecule in the body. It has many different functions but appears to have a role in inflammation of the joints. NO is not the same as the nitrous oxide (N2O or laughing gas) that dentists use.
The results of this study showed that chronic back pain patients had three times as much NO in the perifacetal region compared to healthy subjects. When the joint was injected with a numbing agent and steroid, more than half the patients reported a decrease in back pain.
There is no simple test or way to identify the cause of back pain. Scientists hope to find a molecular marker of pain that will tell us the source of pain. Until that happens, tools like the NO sensor used in this study may be helpful. If NO levels are elevated, treatment with injection may be indicated.