Complications after Fusion for Thoracolumbar Fractures in Patients with Ankylosing Spondylitis

STUDY DESIGN: Retrospective analysis of a Medicare database (2005 to 2012). OBJECTIVE: To study postoperative complication rates following thoracolumbar fusion for traumatic thoracolumbar fracture in patients with ankylosing spondylitis (AS) compared with patients without AS. METHODS: The PearlDiver database (2005 to 2012) was queried to examine postoperative complication rates in patients with AS undergoing posterior thoracolumbar fusion for thoracolumbar fracture (n = 968). Complication rates were compared with proportion-matched controls without AS undergoing the same procedure (n = 1,979). We examined and compared the incidence of death, postoperative infection, transfusion, venous thromboembolism, respiratory failure, pneumonia, myocardial infarction, urinary tract infection, and acute renal failure in each cohort within 90 days postoperatively. RESULTS: Patients with AS had significantly higher rates of surgical site infection (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.2 to 2.2, p = 0.002), day-of-surgery transfusion rates (OR 1.5, 95% CI 1.3 to 1.8, p < 0.0001), respiratory failure (OR 1.8, 95% CI 1.3 to 2.5, p = 0.0006), pneumonia (OR 1.8, 95% CI 1.3 to 2.5, p = 0.0002), acute renal failure (OR 1.6, 95% CI 1.2 to 2.3, p = 0.005), and total medical complications (OR 1.5, 95% CI 1.2 to 1.9, p < 0.0001). Ninety-day mortality was not different between the two cohorts (p = 0.18). CONCLUSIONS: Thoracolumbar fusion for thoracolumbar fracture in patients with AS is associated with increased rates of surgical site infection, transfusion, respiratory failure, pneumonia, and acute renal failure postoperatively compared with patients without AS. The level of evidence in this study was III.