Author Affiliations: Oregon Health and Science University, Portland (Dr Deyo) (firstname.lastname@example.org); and Dartmouth Medical School, Hanover, New Hampshire (Drs Mirza and Martin).
To the Editor: We recently discovered an analytical error in our study on lumbar stenosis surgery.1 This affects our results regarding time trends for surgical procedures (Figure in the article) but not the data concerning complications or charges.
We have discovered that International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for multilevel spine fusions (beyond 2 disc spaces) were instituted only in 2003. We did not account for this in our analysis, due to an oversight, yet these codes comprised one way of meeting our definition of complex fusions. Therefore, in 2002, some complex fusions that were multilevel would have erroneously been classified as simple fusions. This means our reported rate of complex fusions in 2002 was likely artificially low, although we cannot know from the Medicare part A claims what the actual number was. In turn, this means that our estimate of the increase in complex fusion rates was likely artificially high. The values for total fusion procedures remain valid.
Deyo RA, Mirza SK, Martin BI. Error in Trends, Major Medical Complications, and Charges Associated With Surgery for Lumbar Spinal Stenosis in Older Adults. JAMA. 2011;306(10):1088. doi:10.1001/jama.2011.1300