Patient factors that matter in predicting spine surgery outcomes: a machine learning approach

OBJECTIVE There is an increasing recognition of the importance of predictive analytics in spine surgery. This, along with the addition of personalized treatment, can optimize treatment outcomes. The goal of this study was to examine the value of clinical, demographic, expectation, and cognitive appraisal variables in predicting outcomes after surgery. METHODS This prospective longitudinal cohort study followed adult patients undergoing spinal decompression and/or fusion surgery for degenerative spinal conditions. The authors focused on predicting the numeric rating scale (NRS) for pain, based on past research finding it to be the most responsive of the spine patient-reported outcomes. Clinical data included type of surgery, adverse events, comorbidities, and use of pain medications. Demographics included age, sex, employment status, education, and smoking status. Data on expectations related to pain relief, ability to do household and exercise/recreational activities without pain, preventing future disability, and sleeping comfort. Appraisal items addressed 22 cognitive processes related to quality of life (QOL). LASSO (least absolute shrinkage and selection operator) and bootstrapping tested predictors hierarchically to determine effective predictive subsets at approximately 10 months postsurgery, based on data either at baseline (model 1) or at approximately 3 months (model 2). RESULTS The sample included 122 patients (mean age 61 years, with 53% being female). For model 1, analysis revealed better outcomes with patients expecting to be able to exercise or do recreational activities, focusing on recent events, and not focusing on how others see them (mean bootstrapped R-2 [R-boot(2)] = 0.12). For model 2, better outcomes were predicted by expecting symptom relief, focusing on the positive and on one's spinal condition (mean R-boot(2) = 0.38). Bootstrapped analyses documented the stability of parameter estimates despite the small sample. CONCLUSIONS Nearly 40% of the variance in spine outcomes was accounted for by cognitive factors, after adjusting for clinical and demographic factors. Different expectations and appraisal processes played a role in long-versus short-range predictions, suggesting that cognitive adaptation is important and relevant to pain relief outcomes after spine surgery. These results underscore the importance of addressing how people think about QOL and surgery outcomes to maximize the benefits of surgery.