Utilization of Interspinous Devices Throughout the United States Over a Recent Decade: An Analysis of the Nationwide Inpatient Sample

Study Design: Retrospective database study. Objectives: Analysis of economic and demographic data concerning interspinous device (ID) placement throughout the United States to improve value-based care and health care utilization. Methods: The National Inpatient Sample (NIS) database was queried for patients who underwent insertion of an interspinous process spinal stabilization device (ICD-9-CM 84.80) between 2008 and 2014 across 44 states. Demographic and economic data were obtained which included the annual number of surgeries, age, sex, insurance type, location, and frequency of routine discharge. The NIS database represents a 20% sample of discharges from US hospitals, which is weighted to provide national estimates. Results: There was a 73% decrease in ID implanted from 2008 to 2014. The mean cost associated with insertion of the device increased 28% from $13 653 in 2008 to $17 515 in 2014. The mean length of stay (LOS) increased from 1.8 to 2.4 days. Patients aged 45 to 64 years increased from 14.1% to 34.3% while patients aged 65 to 84 years decreased from 74.4% to 60.6%. By region, 34% of ID placement occurred in the South followed by 19.7% that occured in the Northeast. When stratifying by median income for patient zip code, the procedure was performed more in cities designated as higher rather than lower income areas (74.2% and 19.5%, respectively). Conclusions: Throughout the United States, there was a progressive decline in the insertion of interspinous spacers by 73% over the study period. The total costs for the procedure increased by 28% while the aggregate national charges decreased by 55.6% between 2008 and 2014.