BACKGROUND AND OBJECTIVES:It is possible that patients submitted to lumbar spine surgery present chronic pain and need a multidimensional assessment of postoperative pain due to the variables that influence pain. The objective of this study was to evaluate the correlation between uni and multidimensional scales for postoperative pain assessment. METHODS: Longitudinal and observational study carried out in the inpatient units of an orthopedic reference hospital in São Paulo. 53 patients were selected in the preoperative period of lumbar spine arthrodesis, 28 were excluded and 25 were evaluated with the numerical verbal scale and Brief Pain Inventory on the preoperative day and on postoperative day 2. RESULTS: In the sample, all patients had chronic pain with a mean previous pain time of 9.24 years. There was variation between the pre and postoperative periods on the Brief Pain Inventory in almost all items, but only the item regarding the amount of pain ''right now'' (in the moment) was equivalent to the numerical verbal scale (Kappa=almost complete correlation). CONCLUSION: The numerical verbal scale and Brief Pain Inventory were not comparable since the Numerical Verbal Scale showed a worsening of postoperative pain, while the Brief Pain Inventory reflected improvement in the perception of postoperative pain.