What's the best way to tell whether surgery for low back pain has had good results?

The first goal of surgery for low back pain is to reduce or eliminate the presenting condition, which is pain. But what's the best way to tell if pain has been reduced?

There are many ways to gauge patients' pain. Doctors often use a visual analog scale, or VAS, which has patients locate their pain on a scale from zero (no pain) to 100 (the worst pain).

A recent study found that pain scores on VAS were related to other measures of pain and to patients' satisfaction with surgery. In this study, comparing before-and-after pain scores on VAS wasn't felt to be as good as looking at VAS scores after surgery or simply asking patients about changes in pain. Finally, there may be no "best way" to measure changes in pain. Each method captures something slightly different.