LAUSR

he accompanying article reports an observational T study that aimed to compare utilization of spine surgery between the United States and Canada. The authors analyzed administrative datasets from the state of New York and the province of Ontario and found that utilization of elective spine surgery and fusion procedures was nearly threeand four-fold higher per capita in the United States, respectively. Further, patients in the United States who underwent surgery were significantly younger than those who did so in Canada. The analytical approach was credible and the conclusions seem supported by the results, but readers should keep in mind that this study is limited by its use of procedural codes and administrative data that were routinely collected in two very different health care environments. If data were collected with systematically more or less rigor in one setting but not the other, apparently significant associations could be spurious or misleading. This study adds to a growing body of evidence documenting substantial variability in population-level utilization of spine surgery, and there are many interesting possible explanations for this phenomenon. Of these, it is perhaps least plausible that there could exist fundamental differences in the incidence of operative spinal pathology between two samples that share a common border and have similar general demographics. More likely, variability in the values and preferences of patients and surgeons led to important