#65 How Often Is Lumbar Spinal Fusion Performed Prior to Diagnosis of Sacroiliac Joint Disruption?
Poster Presented by: T.A. Holt
S.J. Ackerman (1)
T.A. Holt (2)
T. Knight (3)
D.W. Polly, Jr (4)
(1) Covance Market Access Inc., San Diego, CA, United States
(2) Montgomery Spine Center, Orthopaedic Surgery, Montgomery, AL, United States
(3) Covance Market Access Inc., Gaithersburg, MD, United States
(4) University of Minnesota, Orthopaedic Surgery, Minneapolis, MN, United States
Introduction: The sacroiliac (SI) joint has been reported as the pain generator in 15%-22% of patients with low back pain. The SI joint as a source of low back pain is often overlooked or misdiagnosed as discogenic or radicular low back pain, possibly due to a lack of awareness and also because there is no gold standard for SI joint pain diagnosis. It is uncertain how often lumbar spinal fusion is being performed on patients who really have SI pathology, but one report estimates at least 5% of the time. To gain a better understanding of the frequency with which lumbar spinal fusion is performed prior to a diagnosis of SI joint disruption/degenerative sacroiliitis, we assessed health insurance claims in a commercial payer database.
Methods: A retrospective analysis of claim-level data for commercially-insured patients was performed using the MarketScan® Commercial Claims and Encounters Database of Truven Healthcare. Patients with a primary International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code for SI joint disruption/degenerative sacroiliitis (ICD-9-CM diagnosis codes 720.2, 724.6, 739.4, 846.9, or 847.3) with an initial date of diagnosis (index diagnosis) from 1/1/2005-12/31/2007 were included. We analyzed SI joint disruption/degenerative sacroiliitis patients who underwent lumbar spinal fusion, identified with ICD-9-CM procedure codes 81.05-81.08, 81.35-81.38, and 81.62-81.64, in either the year prior to the index diagnosis of degenerative sacroiliitis/SI joint disruption or in the subsequent three years (through 12/13/2010). Only patients with continuous enrollment for all 4 years were included in the analysis.
Results: Of the 78,533 commercially-insured patients diagnosed with SI joint disruption/degenerative sacroiliitis, 434 patients (0.6%) underwent a lumbar spinal fusion. Of these 434 patients, 17.3% underwent lumbar spinal fusion within one year prior to receiving a diagnosis of SI joint disruption/degenerative sacroiliitis, whereas the remainder underwent lumbar spinal fusion following diagnosis of SI joint disease.
Discussion and Conclusion: The diagnosis of SI joint disruption/degenerative sacroiliitis within one year following lumbar spinal fusion may represent concomitant disease, subsequent development of new SI joint disease, or misdiagnosis of lumbar disc disease in patients who actually have SI joint disease. Future research will focus on teasing apart these patient groups and better understanding medical resources and costs, particularly among those patients who potentially have been misdiagnosed.