['Low back pain is common and originates in the sacroiliac (SI) joint in 15%-30% of cases. Traditional SI joint disruption/degenerative sacroiliitis treatments include nonoperative care or open SI joint fusion. To evaluate the usefulness of newly developed minimally-invasive technologies, the costs of traditional treatments must be better understood. We assessed the costs of nonoperative care for SI joint disruption to commercial payers in the United States (US).', 'A retrospective study of claim-level medical resource use and associated costs used the MarketScan® Commercial Claims and Encounters as well as Medicare Supplemental Databases of Truven Healthcare. Patients with a primary ICD-9-CM diagnosis code for SI joint disruption (720.2, 724.6, 739.4, 846.9, or 847.3), an initial date of diagnosis from January 1, 2005 to December 31, 2007 (index date), and continuous enrollment for ≥1 year before and 3 years after the index date were included. Claims attributable to SI joint disruption with a primary or secondary ICD-9-CM diagnosis code of 71x.xx, 72x.xx, 73x.xx, or 84x.xx were identified; the 3-year medical resource use-associated reimbursement and outpatient pain medication costs (measured in 2011 US dollars) were tabulated across practice settings. A subgroup analysis was performed among patients with lumbar spinal fusion.', 'The mean 3-year direct, attributable medical costs were $16,196 (standard deviation [SD] $28,592) per privately-insured patient (N=78,533). Among patients with lumbar spinal fusion (N=434), attributable 3-year mean costs were $91,720 (SD $75,502) per patient compared to $15,776 (SD $27,542) per patient among patients without lumbar spinal fusion (N=78,099). Overall, inpatient hospitalizations (19.4%), hospital outpatient visits and procedures (14.0%), and outpatient pain medications (9.6%) accounted for the largest proportion of costs. The estimated 3-year insurance payments attributable to SI joint disruption were $1.6 billion per 100,000 commercial payer beneficiaries.'] Is management of sacroiliac joint disruption and degenerative sacroiliitis with nonoperative care medical resource-intensive and costly in a United States commercial payer population?