Trends in Utilization and Cost of Cervical Spine Surgery Using the National Inpatient Sample Database, 2001 to 2013

Study Design. A retrospective review. Objective. The aim of this study was to determine national rates of cervical spine surgery and to examine factors that underlie cost variation. Summary of Background Data. There has been an increase in the rate and cost of spinal surgery over the past decades, but there is little understanding of the drivers of cost variation at the national level. Methods. We analyzed 419,830 patients who underwent cervical spine surgery (anterior cervical fusion, posterior cervical fusion, posterior cervical decompression, combined anterior/posterior cervical fusion) for degenerative conditions in the 2001 to 2013 NIS database. We determined the rates of surgery by time and geographic region, and then created univariate and multivariate models to evaluate the effect of these factors on total hospital costs: patient age, gender, race, insurance, income, county of residence, elective versus nonelective case, length of stay, risk of mortality, severity of illness, hospital bed size, wage index, hospital type, and geographic region. Results. The most common type of cervical spine surgery was anterior fusion (80.6% of all surgeries). The national rates of all cervical spine surgery decreased slightly from 2001 to 2013 (75.34 to 72.20 per 100,000 adults), while the mean inflation-adjusted cost increased 64%, from $11,799 to $19,379, during this time period. Multivariate analyses showed that older age, male gender, black/other race, private insurance, greater risk of mortality/severity of illness, and longer length of stay were associated with higher costs. The wage index was positively correlated with cost, and hospitals in the western U.S. were 27% more expensive than those in the Northeast. Conclusion. The rate of cervical spine surgery decreased slightly, while the mean case cost increased at a rate double that of inflation from 2001 to 2013. Even after controlling for patient and hospital factors including wage index, there was significant geographic variation in the cost for cervical spine surgery.