Cost-effectiveness of conservative versus surgical treatment strategies of lumbar spinal stenosis in the Swiss setting: analysis of the prospective multicenter Lumbar Stenosis Outcome Study (LSOS)

To evaluate the cost-effectiveness of conservative versus surgical treatment strategies for lumbar spinal stenosis (LSS). Patients prospectively enrolled in the multicenter Lumbar Stenosis Outcome Study (LSOS) with a minimum follow-up of 12 months were included. Quality adjusted life years (QALY) were calculated based on EQ-5D data. Cost data were retrieved retrospectively. Cost-effectiveness was calculated via decision tree analysis. A total of 434 patients were included, treated surgically (n = 170) or conservatively (n = 264) for LSS. The majority of surgically treated patients underwent decompression (n = 141, 82.9%), and 17.1% (n = 29) additionally underwent fusion. A reoperation was required in 13 (7.6%) surgically treated patients. In 27 (10.2%) conservatively treated patients, a single infiltration was successful, with no further infiltration or surgery within the follow-up. However, 46 patients (17.4%) required multiple infiltrations, and in 191 (72.4%) initially conservatively treated patients a subsequent surgery was needed. The area under the curve was 0.776 QALY in the surgical arm (0.776 and 0.790, decompression or additional fusion, respectively), compared to 0.778 in the conservative arm. Treatment costs were estimated at CHF 12,958 and 13,637 (USD 13,465 and 14,169) in surgically and initially conservatively treated patients, respectively [base-case incremental cost-effectiveness ratio (ICER): CHF 392,145, USD 407,831], per QALY gained. Probabilistic sensitivity analysis identified surgery as the preferred strategy in 67.1%. Both the surgical and the conservative treatment approach resulted in a comparable health-related quality of life within the first year after study inclusion. Due to slightly higher costs, mostly because the majority of initially conservatively treated patients underwent multiple infiltrations or a subsequent surgery, decompressive surgery was identified as the most cost-effective approach for LSS in this setting.