Background <p>Percutaneous epidural adhesiolysis (PEA) is an alternative intervention used to relieve pain in patients with lumbar spinal stenosis who do not respond to standard treatment and epidural steroid injection (ESI). Although it provides better and longer pain control, it comes at a higher cost. This study aimed to evaluate cost-effectiveness in patients with lumbar spinal stenosis in Thailand from a social perspective.</p> Methods <p>A model-based cost-utility analysis was performed using a Markov model to evaluate the costs and quality-adjusted life years of PEA in patients with lumbar spinal stenosis, aged 50 years. The analysis compared patients who received a single ESI prior to PEA (ESI-PEA), with those receiving two ESIs (ESI-ESI) and the standard treatment. The Markov model simulated patient transitions between health states, including improved, unimproved, and death states, over a 24-month time horizon. One-way sensitivity analysis was performed to assess the effect of single variables, whereas probabilistic sensitivity analysis (PSA) was conducted using Monte Carlo simulations to account for uncertainty across multiple parameters.</p> Results <p>This study revealed that the standard treatment had the lowest cost of THB 242,101, whereas the ESI-PEA had the highest cost of THB 274,250 and the highest QALY of 0.8542. The incremental cost-effectiveness ratio of ESI-ESI and ESI-PEA compared to standard treatment were 961,014 and 1,891,117 THB per QALY, respectively, which exceeded Thailand’s willingness to pay threshold of 160,000 THB/QALY. Uncertainty analysis indicated that the most influential variable was the utility value of non-improved patients.</p> Conclusions <p>ESI-PEA and ESI-ESI are not cost-effective compared to standard treatment in the Thai context. These findings provide valuable insight for policymakers when considering treatment options for lumbar spinal stenosis in resource-limited settings.</p>