CHANGES IN UTILIZATION OF SPINAL FUSIONIN THE UNITED STATES

Abstract

OBJECTIVE Several reports suggest that spine surgery has experienced rapid growth in the past decade. Limited data exists, however, documenting the increase in spinal fusion. The objective of this work was to quantify and characterize the contemporary practice of spinal fusion in the United States. METHODS Clinical data was obtained from the Nationwide Inpatient Sample (NIS) for 1993 to 2001. All patients with ICD-9-CM procedure codes indicating cervical fusion, thoracolumbar fusion, lumbar or unspecified fusion were identified (n = 249,429). Primary ICD-9-CM diagnosis codes were used to determine the rationale for surgical fusion. Population-based utilization rates overall and for each procedure were calculated from United States census data. Rank order of spinal fusion compared to other inpatient procedures from the NIS was reported for the years 1997 to 2003. RESULTS Overall utilization increased during the time period for cervical, thoracolumbar, and lumbar fusions by 433%, 52%, and 356%, respectively. Patients age 40 to 59 experienced the rapid rise in utilization for cervical fusions (15–87 per 100,000) and lumbar fusions (13–63 per 100,000). For patients 60 and older utilization also increased for cervical (9–44 per 100,000), thoracolumbar (2–5 per 100,000) and lumbar (13–68 per 100,000). For all spinal fusions combined, a primary diagnosis of degenerative disc disease was noted in 39.4% of patients in 1993 and increased to 65.3% by 2001 (P < .001). Spinal fusion rose from the 41st most common inpatient procedure in 1997 to the 19th in 2003. CONCLUSION Cervical, thoracolumbar, and lumbar spinal fusion have experienced a rapid increase in utilization in isolation and compared to other surgical procedures in contemporary practice. These changes are most pronounced for patients over 40 years of age and degenerative disc disease appears to account for much of this increase.