Preoperative functional status as a predictor of short-term outcome in adult spinal deformity surgery

Adult spinal deformity (ASD) may cause severe disability and difficulty with daily activities. The purpose of this study was to investigate the impact of preoperative functional status on 30-day major complication occurrence in ASD surgery. A review of the prospectively-collected American College of Surgeons National Surgical Quality Improvement database was performed for the years 2007-2013. Inclusion criteria were adult patients (over 21years of age) who underwent spinal fusion for ASD. Functional status was defined as "independent" or "dependent" (requiring assistance from another person) for activities of daily living such as bathing, dressing, feeding, toileting, or mobility. The association between functional status and complications (overall and major) was investigated via multivariate analysis. Results are presented as odds ratios (OR) with 95% confidence intervals (CI). A total of 1247 patients met inclusion criteria (94.4% independent and 5.6% dependent patients). The overall 30-day complication rate was 16.0% (15.6% for independent patients and 22.9% for dependent patients, p=0.10); major complications occurred in 9.2% of independent patients and 17.1% for dependent patients (p=0.02). After controlling for patient age, smoking status, preoperative hematocrit, revision status, use of osteotomy, number of levels fused, and operative time, being dependent on another person for activities of daily living was found to be a significant predictor of major complication development (OR 2.09; 95% CI, 1.04-4.20; p=0.03). Depending on others for activities of daily living before undergoing ASD surgery may predict the development of major perioperative complications, increasing the risk by 2-fold compared to independent patients.