Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Introduction:

Up to one-third of patients experience limited benefit following surgical intervention for common degenerative lumbar conditions. There is significant variability in reported prognostic factors with studies being limited by the number of variables and/or sample size as well as a specific diagnosis. Furthermore, although there is growing recognition that outcomes vary by sex, there has been relatively limited work taking a sex-specific approach to investigating predictors of outcome in this clinical population. As such, the objective of this study is to determine unique prognostic factors associated with patient reported pain related disability outcome one-year following spine surgery in males and females.

Methods:

Data from the Canadian Spine Outcomes and Research Network (CSORN) database (2015-2023) was analyzed for patients with common degenerative lumbar diagnoses. Multivariate logistic regression models were created to predict minimally clinically important difference (MCID) achievement based on 30% improvement in the Oswestry Disability Index (ODI) at one-year follow-up. Sex stratified analysis was conducted to analysis differences between men and women. Patient diagnosis and a comprehensive list of patient factors (n = 110 variables) were used as inputs. Stepwise selection minimized the Akaike Information Criterion (AIC), with significance set at P<0.05. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each variable.

Results:

The study included 6,214 patients, with diagnoses of lumbar spinal stenosis-LSS (2,175), degenerative disc-DD (456), disc herniation-LDH (1,279), degenerative spondylolisthesis-DLS (1,591), isthmic spondylolisthesis-IS (361), and degenerative scoliosis-DS (352). The average (SD) age was 60.1 (13.4) with men and women evenly distributed (3,142 (50.6%) and 3,072 (49.4%), respectively).

A summary of factors across both cohorts is found in Table 1. Key common predictive factors across both male and female cohorts were age, baseline ODI score, comorbidities, DLS, IS, smoking, unemployed/other work status, those on worker’s compensation, and daily narcotics use. Factors that were only significant in the male cohort were postgraduate education, employed but not working, legal consultation obtained, medication for back pain, medication duration use >1 year, intermittent narcotics use, and expected improvement in sporting activities. Factors that were only significant in the female cohort were BMI, baseline back and leg pain, and over the counter medication use.

When combining both cohorts and adjusting for sex, the factors that were significant but not in each cohort separately with ORs (95% CI) were living with a partner 1.23 (1.06, 1.43) and less than highschool education 0.8 (0.66, 0.97).

Discussion:

This study outlines prognostic factors related to achieving MCID for pain related disability across common degenerative lumbar conditions one-year following surgery. A number of factors uniquely influenced outcomes for males and females, suggesting that simply adjusting for sex effects in regression analyses may not be sufficient to identify sex differences. This has implications for the interpretation and use of current prognostic evidence; and future development of predictive algorithms for ODI outcome following spine surgery. It also has implications for patient education and decision-making, and suggests that interventions to optimize outcomes may require a sex-specific approach.