Changes in the utilization of spinal fusion in the United States

Several reports suggest that spine surgery has experienced rapid growth in the past decade. Limited data exist, 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.

Clinical data were obtained from the Nationwide Inpatient Sample for the years from 1993 to 2003. All patients with International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes indicating cervical fusion, thoracolumbar fusion, lumbar or unspecified fusion were identified (n = 471,990). 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 with other inpatient procedures from the Nationwide Inpatient Sample was reported for the years 1997 to 2003.

Overall utilization increased during the time period for cervical, thoracolumbar, and lumbar fusions by 89, 31, and 134%, respectively. Patients aged 40 to 59 years experienced the rapid rise in utilization for cervical fusions (60-110 per 100,000) and lumbar fusions (35-84 per 100,000). For patients 60 years and older, utilization also increased for cervical (30-67 per 100,000), thoracolumbar (4-9 per 100,000), and lumbar (42-108 per 100,000). Spinal fusion rose from the 41st most common inpatient procedure in 1997 to the 19th in 2003.

Cervical, thoracolumbar, and lumbar spinal fusion have experienced a rapid increase in utilization in isolation and compared with other surgical procedures in contemporary practice. These changes are most pronounced for patients over 40 years of age, and degenerative disc disease seems to account for much of this increase.