Clinical decision-making for decompression-level selection in multilevel degenerative lumbar spinal stenosis: a retrospective cohort study

To characterise changes in decompression-level selection during sequential preoperative assessment in patients with multilevel degenerative lumbar spinal stenosis (DLSS) and to describe postoperative outcomes and subsequent events involving initially untreated candidate levels.

This retrospective single-centre cohort included 168 patients with two to four  MRI-defined candidate levels who underwent endoscopic decompression. Planned decompression levels were reconstructed before walking load testing (WLT), after WLT, after selective nerve root block (SNRB) when performed, and at the final preoperative assessment. Postoperative clinical outcomes and subsequent events involving initially untreated candidate levels were recorded during 24 months of follow-up.

Planned level sets changed after WLT in 72/168 patients (42.9%), and final plans differed from initial imaging-informed plans in 87/168 patients (51.8%). Among 55 patients undergoing SNRB, post-WLT plans were modified in 22 (40.0%). All final planned levels were decompressed. At 24 months, 143 patients (85.1%) completed follow-up, with a model-estimated 38.44-point improvement in the Oswestry Disability Index (ODI); 123/143 (86.0%) achieved the ODI threshold for patient acceptable symptom state (PASS). Among 231 initially untreated candidate levels, five underwent delayed decompression, with a 24-month Kaplan-Meier estimate of 2.6% (95% CI 1.1-6.0).

Sequential incorporation of imaging, functional assessment, and selective diagnostic procedures was associated with changes in planned decompression levels in patients with multilevel DLSS. This study describes surgical decision-making and the subsequent clinical course of initially untreated candidate levels after selective decompression planning.