Special Poster Session 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Introduction: Lumbar spinal stenosis due to osteoarthritis (LSS-OA) is a leading cause of pain and disability. While nonsurgical treatment has limited efficacy for end-stage disease, surgical intervention for selected patients is generally associated with good patient-reported outcomes. However, up to one-third experience limited benefit. Identifying contributors to poorer response is important.

In prior work, greater symptomatic appendicular joint burden contributed to poorer outcomes. However, patients with LSS-OA often also have disc degeneration at multiple levels, beyond the surgical level(s). This has received limited attention in regards to understanding outcomes. We documented the occurrence and evaluated the influence of lumbar disc degeneration (LDD) burden on Oswestry Disability Index (ODI) outcomes following LSS-OA surgery.

Methods: 121 patients underwent decompression surgery+/-fusion for LSS-OA. ODI was patient-completed pre- and 12-months post-surgery. Additional factors: age, sex, education, BMI, fusion+/-, spondylolisthesis+/-, smoking, comorbidities, symptomatic appendicular joint count, depression, anxiety. Modified Pfirrmann disc grading was performed for each lumbar level, scored 0 (grade 1, ‘none’), 1 (grade 2/3, ‘mild’), 2 (grade 4, ‘moderate’), or 3 (grade 5, ‘severe’). Individual level scores were summed, yielding an overall LDD score (range: 0-15). Based on preliminary work, individuals were grouped: LDD score 0-6 (group-1), 7-10 (group-2), and 11+ (group-3). LLD group influence on 12-month post-surgery outcomes a) ODI status score, and b) ODI percentage change, were examined using linear regression adjusting for noted additional factors.

Results: Mean age: 67.2 years, 43.8% female. Mean LDD score: 8.9/15. Nearly 20% were classified as LDD group-1 (mean LDD score 5.5; lowest LDD burden), 54.5% as group-2 (mean score 8.4), and 25.6% as group-3 (mean LDD score 12.6; greatest LDD burden). Individuals with greater LLD burden were older and with more comorbidities. Proportion reporting 3+ symptomatic appendicular joints increased from 46% to 58%, LDD group-1 to -3. LDD group-1 had mean 12-month ODI score=18.8, and mean 12-month score change=57.3%. Equivalent values for group-2: 20.0 and 52.2%, and group 3 (greatest LDD burden): 26.7 and 28.1%. Proportion achieving ≥30% ODI improvement was 50% among LDD group-3 vs. 71% and 74% in groups-1 and -2. Adjusted analyses (see Fig): 12-month ODI percentage improvement scores in group-3 were on average 21.5 percentage points lower vs. group-1 (p=0.04), and 12-month scores were 10.7 units higher (worse) in group-3 vs. group-1 (p=0.007). Also contributing to poorer percentage improvement: greater symptomatic appendicular joint burden (16.1 percentage points lower for 3+ symptomatic joints vs. 0-2 (p=0.02)), and worse anxiety score (16.9 points lower per 5-unit increase in score (p<0.01)).

Discussion: Independently, LDD burden was strongly associated with disability outcome following LSS-OA surgery. For those with high LDD burden, half failed to achieve meaningful improvement. Findings point to a need to consider multilevel spine burden, and multi-appendicular joint burden, to understand spine OA outcomes. Similar to appendicular OA, this overall burden may reflect a systemic, largely inflammatory, profile for a subgroup of LSS-OA. Work was limited to lumbar region imaging data. A comprehensive characterization of spinal disease burden in OA will require whole spine disc degeneration and facet joint OA consideration.