I had a nerve block to stop my low back pain from a chronic facet joint problem. I got good pain relief for about a year. It's starting to come back now. Should I have this same treatment again soon?

There are many gray areas in the treatment of chronic low back pain using nerve blocks. How much pain relief makes this treatment worth it? And for how long?

A recent study from the San Francisco Spine Institute used 50 percent pain relief as its deciding factor. Anyone who got relief from 50 percent (or more) of their pain was considered to have a "successful" treatment.

Fifty percent was used because other studies show a link between patient satisfaction and 50 percent pain reduction. Each patient must decide for him or herself how much pain relief is enough to make it worth a second (or third ... or more) treatment(s).

At least 85 percent of all patients who have a repeat nerve block get pain relief that lasts an average of 10.5 months. Some even had up to seven repeated treatments.