What is the Marginal Intraoperative Cost of Using an Exoscope or Operative Microscope for Anterior Cervical Discectomy and Fusion? A Time-Driven Activity-Based Cost Analysis

Abstract

Our primary objective was to compare the marginal intraoperative cost of three different surgical visualization techniques for anterior cervical discectomy and fusion (ACDF). Specifically, we used time-driven activity-based costing (TDABC) methodology to compare costs between ACDFS performed with operative microscopes (OM-ACDF), exoscopes (EX-ACDF), and loupes (loupes-ACDF). Total cost was divided into direct and indirect costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments (business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented. We identified all instances of loupes-ACDF (n=882), EX-ACDF (n=26), and OM-ACDF (n=52) performed at our institution. We performed multivariable linear regression analyses to compare costs between these modalities, accounting for patient-specific factors as well as number of levels fused, surgeon, and hospital site. The average total intraoperative costs per loupes-ACDF, EX-ACDF, and OM-ACDF cases were $7,081 +/- $2,942, $7,951 +/- $3,488, and $6,557 +/- $954, respectively. Regression analysis revealed no difference in intraoperative cost between loupes-ACDF and EX-ACDF (p=0.717), loupes-ACDF and OM-ACDF (0.954), or OM-ACDF and EX-ACDF (0.217). On a more granular level, however, EX-ACDF was associated with increased cost of consumables, including drapes, compared to both OM-ACDF (β-coefficient: $369 +/- $121, p=0.002) and loupes-ACDF (β-coefficient: $284 +/- $86, p=0.001). Although hospitals may be aware of the purchasing fees associated with microscopes and exoscopes, there is no clear documentation of how these technologies affect intraoperative cost. We demonstrate a novel use of TDABC for this purpose.