Direct Variable Cost Comparison of Monitored Anesthesia Care Versus Wide Awake Local Anesthesia No Tournique Carpal Tunnel Release: A Time-Driven Activity-Based Costing Analysis

Abstract

Time-driven activity-based costing (TDABC) provides a more accurate and granular estimation of direct variable costs compared with traditional accounting methods. This study used TDABC to quantitatively compare the same-day facility costs of open carpal tunnel release (CTR) performed under monitored anesthesia care (MAC) versus wide awake local anesthesia no tourniquet (WALANT). We retrospectively identified 474 unilateral CTR (182 MAC and 292 WALANT) performed at an orthopedic specialty hospital between 2015 and 2021. Itemized facility costs were calculated using a TDABC algorithm. Patient demographics, surgical characteristics, and itemized costs were compared between those treated under MAC (MAC-CTR) and WALANT (WALANT-CTR). Multivariable regression was performed to determine the independent effect of MAC on true facility costs. Total facility costs were $170 higher in MAC-CTR compared with WALANT-CTR ($652 vs $482). Monitored anesthesia care-CTR cases had higher personnel costs ($537 vs $394), likely because of higher surgery personnel ($303 vs $185) and postanesthesia care unit personnel costs ($117 vs $95). Monitored anesthesia care-CTR cases also had higher supply costs ($119 vs $81). When controlling for demographics and comorbidities, MAC-CTR was independently associated with an increase in personnel costs by $150.65 (95% CI, $131.09-$170.21), supply costs by $24.99 (95% CI, $9.40-$40.58), and total facility costs by $175.66 (95% CI, $150.18-$201.09) per case. Using TDABC, MAC-CTR was found to be 35% more costly to the facility compared with WALANT-CTR. Notably, WALANT-CTR facility costs presented here do not include additional cost savings from anesthesiologist service fees or preoperative laboratory clearance required for MAC-CTR surgeries. To reduce costs related to CTR surgery, greater efforts should be made to reduce the number of intraoperative personnel and maximize the use of WALANT-CTR in an outpatient setting. Economic and Decision Analysis II.