Medical Student Heersink School of Medicine, University of Alabama at Birmingham
Introduction: Thirty-day unplanned readmissions and post-operative complications are common following lumbar spine surgery, but the socioeconomic risk factors for these outcomes remain understudied. Recent studies have highlighted the role of the Social Vulnerability Index (SVI) in predicting post-operative outcomes, but SVI’s effect on readmissions and complications following lumbar spine surgery is unclear. We sought to assess the association of SVI with readmissions, reoperations and post-operative complications following lumbar spine surgery in a large cohort.
Methods: We retrospectively reviewed all adult patients at a single institution from 2011 to 2023 who underwent open and minimally invasive lumbar spine surgery using CPT and ICD9/10 codes. Addresses were geocoded and SVI were extracted from the CDC, with high socioeconomic disadvantage defined as the top quartile of SVI. Propensity score matching and multivariate analyses were performed to assess the effect of SVI and other variables on readmission rates, reoperation rates, and complications.
Results: We identified 4282 patients who met the inclusion criteria. The median age at time of operation was 64 [Interquartile Range (IQR) 55 -71] and 16% were African American and 19.5% of patients had high SVI. Of these, 48% were fusion operations. In multivariate regression analysis adjusting for clinical and other socioeconomic factors, patients with high SVI had independently higher odds of 30-day (OR 1.63, p = 0.47) and 90-day (OR 1.57, p=0.012) readmissions. After propensity score matching by demographics, comorbidity burden, levels operated on, patients with high SVI had higher rates of post-operative acute kidney injury (1.6% vs 0.5%, p=0.005) and altered mental status (1.1% vs 0.3%, p=0.021). Patients with high SVI also had higher rates of reoperation within 90 days (4.5% vs 2.9% p =0.037), readmission within one year (11% vs 3.7%, p=0.027), reoperation within one year (9.7% vs 7.2%, p =0.033) of index surgery.
Conclusion : We present to our knowledge the first validation of SVI as an independent risk factor for increased unplanned readmissions, reoperations, and complications. SVI is a novel metric that may offer accurate prognostic evaluation for patient’s post-operative course. Indices that integrate multiple aspects of socioeconomic status such as SVI should be considered in surgical optimization.