Most quality improvement efforts in surgery have focused on the technical quality of care provided, rather than whether the care was indicated, or could have been provided with a safer procedure. Because risk is inherent in any procedure, reducing the number of unnecessary operations is an important issue in patient safety. In the case of lumbar spine surgery, several lines of evidence suggest that, in at least some locations, there may be excessively high surgery rates. This evidence comes from international comparisons of surgical rates; study of small area variations within countries; increasing surgical rates in the absence of new indications; comparisons of surgical outcomes between geographic areas with high or low surgical rates; expert opinion; the preferences of well-informed patients; and increasing rates of repeat surgery. From a population perspective, reducing unnecessary surgery may have a greater impact on complication rates than improving the technical quality of surgery that is performed. Evidence suggests this may be true for coronary bypass surgery in the US and hysterectomy rates in Canada. Though similar studies have not been done for spine surgery, wide geographic variations in surgical rates suggest that this could be the case for spine surgery as well. We suggest that monitoring geographic variations in surgery rates may become an important aspect of quality improvement, and that rates of repeat surgery may bear special attention. Patient registries can help in this regard, if they are very complete and rigorously maintained. They can provide data on surgical rates; offer post-marketing surveillance for new surgical devices and techniques; and help to identify patient subgroups that may benefit most from certain procedures.