Abstract
OBJECTIVE
Transforaminal endoscopic lumbar discectomy (TELD) has yet to achieve widespread adoption, in large part due to an unclear understanding of cost drivers. Therefore, using time-driven activity-based costing (TDABC), the authors sought to 1) compare risk-adjusted differences in the true costs (not charges or reimbursement) of TELD versus open and tubular microdiscectomy, and 2) identify independent predictors of cost for TELD.
METHODS
A retrospective cohort study (2020–2024) was conducted of all cases of TELD and microdiscectomy performed at a single institution. The primary exposure was procedure: TELD, open microdiscectomy, or tubular microdiscectomy. The primary outcome was cost, calculated using TDABC. Bayesian hierarchical regression was performed to 1) estimate risk-adjusted cost differences between procedures and 2) identify independent predictors of cost for endoscopy. Covariates included age, sex, American Society of Anesthesiologists (ASA) class, use of navigation, disc herniation (central/paracentral, foraminal/extraforaminal, or lateral recess/subarticular), number of decompressed levels, and surgeon.
RESULTS
A total of 503 patients underwent TELD (113, 22.5%) or microdiscectomy (390, 77.5%) for lumbar disc herniation. After adjusting for confounders, TELD was significantly more expensive than both open microdiscectomy (mean difference [MD] $1105, 95% Bayesian credible interval [BCI] $846–$1392) and tubular microdiscectomy (MD $1012, 95% BCI $616–$1432), driven by greater cost of consumables, particularly access/navigation kits (i.e., spinal access kits, endoscopic portals) and specialized instruments (i.e., high-speed drills, endoscopic forceps). Personnel costs did not differ significantly across procedures. Factors independently associated with greater cost for endoscopy included use of intraoperative navigation, patient ASA class, and disc herniation location. Specifically, navigation increased total cost by approximately 29% (estimate 0.258, 95% BCI 0.158–0.358; > 99.9% posterior probability). Likewise, each 1–standard deviation increase in ASA class increased cost by 4.2% (estimate 0.042, 95% BCI 0.004–0.080; 98.4% posterior probability). Compared to foraminal/extraforaminal herniations, central/paracentral herniations increased cost by 7.4% (estimate 0.071, 95% BCI 0.000–0.140; 97.6% posterior probability).
CONCLUSIONS
TELD was more expensive than both open and tubular microdiscectomy, largely driven by more expensive consumables. Moreover, both modifiable and nonmodifiable factors were identified as independent drivers of cost for endoscopy. Continued refinement of technique and patient selection, along with targeted vendor negotiations to reduce consumable costs, may improve both the economic viability and overall utilization of endoscopy.