Time-Driven Activity-Based Costing for Transsphenoidal Endoscopic Pituitary Surgery: What Are the True Drivers of Cost?

Introduction: Neurosurgeons often lack precise insights into the true costs associated with transsphenoidal endoscopic pituitary surgery (TEPS). This is due to limitations of conventional costing systems such as cost-to-charge ratios, which are heterogeneous across institutions and overestimate the true cost of care. To address this critical gap, we propose the application of time-driven activity-based costing (TDABC), a bottom-up costing strategy which is now recognized as the gold standard way to accurately quantify the true cost of care delivery.

Methods: We conducted a retrospective analysis of 222 TEPS procedures performed between 2017 and 2022 at a large academic medical center. Costs were calculated using the TDABC methodology. Detailed process maps were constructed to capture all material and personnel resources utilized intraoperatively ([Fig. 1]). To streamline the data extraction process, we developed software capable of automatically retrieving this information from the electronic medical record (EMR). Supply costs were calculated as the aggregate of expenses related to intraoperatively utilized items, including implants, consumables, medications, and surgical tray sterilization. Personnel costs were determined in a multistep process: we first identified the specific personnel involved in each case, as documented in the EMR, as well as their annual wage. We then multiplied the per-minute wage for each personnel type by the total minutes spent by each personnel in the operation. Cumulatively, this defined total personnel cost. Indirect costs, such as those associated with operating room (OR) usage and turnover, were also included in the overall cost calculation. Multivariable linear regression was utilized to identify significant contributors to total intraoperative cost.

Fig. 1: Process map used to identify intraoperative resources and timestamps.

Results: The average total cost for a transsphenoidal pituitary procedure was $7,389 ± $2,420 ([Fig. 2]), with primary cost components being supplies ($2,722, 37%) and personnel ($4,349, 59%; [Fig. 3]). Multivariable regression analysis revealed that gross total resection (GTR) (β-coefficient: $551 ± $241, p = 0.023), hormone-secreting adenomas (β-coefficient: $886 ± $392, p=0.025), hospital site (β-coefficient: $1,033 ± $441, p = 0.02), and operative times (β: coefficient: $14 ± $4, p = 0.002) were significantly associated with total cost. The model performance as measured by R2 was 0.76. Importantly, surgeon-specific factors and patient comorbidities were not significantly associated with cost variations.

Fig. 2 Histogram depicting case frequency for specific cost ranges.

Fig. 3 Pie charts demonstrating subcomponents of cost.

Conclusion: To our knowledge, this study represents the first application of TDABC to pituitary surgery. We demonstrate both fixed and modifiable sources of variation in intraoperative cost, which may be of great interest to healthcare stakeholders in light of emerging value-based reimbursement models. Moreover, efforts such as ours can highlight inefficiencies in neurosurgical practices, which may change the way practices perform pituitary surgery.

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Artikel online veröffentlicht:
07. Februar 2025