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.

Purpose: 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).

Methods: 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.

Results: 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.

Conclusions: 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.

Type Of Study/level Of Evidence: Economic and Decision Analysis II.