Temporal trends in pre-surgical evaluations and epilepsy surgery in the U.S. from 1998 to 2009

To analyze trends in utilization of pre-surgical evaluations including video-EEG (VEEG) monitoring, intracranial EEG (IEEG) monitoring, and epilepsy surgery from 1998 to 2009 in the U.S.

Data from the Nationwide Inpatient Sample were used to identify admissions for pre-surgical evaluations and surgery. Surgical treatment of epilepsy was identified by the presence of primary ICD-9-CM procedure codes 01.52 (hemispherectomy), 01.53 (lobectomy), or 01.59 (other excision of the brain, including amygdalohippocampectomy). We calculated annual rates of pre-surgical evaluations and surgery based on published estimates of prevalence of epilepsy in the U.S. In addition, we examined variations by region and hospital characteristics, and conducted multivariable analysis to detect temporal trends, adjusting for changes in the population. Sensitivity analysis was also conducted using different algorithms to identify the study population and outcomes.

We detected an increase in the rate of hospitalizations related to intractable epilepsy. Similarly, we noted a significant increase in hospitalizations for VEEG monitoring, but not in IEEG monitoring or in surgery. Multivariable analysis and sensitivity analysis confirmed these results. In addition, there was a significant increase in the proportion of pre-surgical evaluations and surgery performed in non-teaching hospitals.

Despite the increase in VEEG monitoring, the availability of guideline and evidences demonstrating benefits of epilepsy surgery was not associated with a greater employment of surgery over time. Nevertheless, access to pre-surgical evaluations and epilepsy surgery is no longer limited to large medical centers.