A new research suggests that slavishly following long-held guidelines for diagnosing the cause of arthritis-related back pain is resulting in excessive tests, delays in pain relief and wasteful spending of as much as 10,000 dollars per patient.

Arthritis is a common cause of back pain, though difficult to precisely diagnose, experts say, because of the poor correlation between a finding of arthritis on an X-ray or MRI and the degree of a patient's back pain.

"The whole way we're doing this is wrong," says study leader Steven P. Cohen, M.D., an associate professor of anaesthesiology and critical care medicine at the Johns Hopkins University School of Medicine.

"If we just do the radio frequency procedure first, we're going to help more people and we're going to save a lot of money."

The study revealed that among those who had radio-frequency treatment, success rates were higher in those who had the diagnostic blocks first because they were more likely to actually have arthritis.

"When you do two blocks, you may be wrongly weeding out many people who would actually benefit from radio-frequency denervation," said Cohen.

Cohen notes that radiofrequency denervation is as safe as giving a diagnostic block and need only be done once for relief of symptoms.

The relief can last many months and sometimes years, but often must be repeated when pain returns.

Cohen and colleagues believe that making diagnostic accuracy a higher priority than pain relief may be misguided.

"If you ask patients what their main goal of treatment is, the answer is typically that they want to be able to pick up their grandkids or play golf. It's not, 'I want to know if it's my arthritic joints or my discs.'"

Cohen cautions that diagnostic nerve blocks are called for in some cases.

For example, they should be used to determine whether surgery is the right option for relieving certain kinds of back pain in people without a clear-cut anatomical problem in order to avoid an unnecessary, risky operation.

The new study is published in the August issue of the journal Anaesthesiology.