Risk factors for non-neurological complications in adult spinal deformity surgery: an international, prospective, multi-center study of 269 patients

Abstract

INTRODUCTION: High risk of complications has been noted in patients with complex adult spine deformity surgery. Although the overall complication rates had been reported, they are variable and can range from 14 to 46%. However, these studies were retrospective cohorts without a clear definition of inclusion criteria and systematic collection of clinical data. As such, a complete risk profile and an accurate complication rate remain unclear. The objectives of this study were to establish the prevalence and risk factors for non-neurological complications within first 6 months of surgery. METHODS: This is the first prospective, multicenter study involving 15 sites from North America, Europe, and Asia. Adult patients with severe spinal deformity were followed for 6 months postoperatively. Demographic characteristics, comorbidities, functional scores, and radiographic measurements were used to determine the risk factors using multivariate modeling. RESULTS: A total of 269 patients (68% women and 32% men) were recruited (mean age: 57.8 years). Overall, 163 patients (60.6%) reported at least one incidence of complication. The prevalence of intraoperative event and postoperative complications were 29.4 (n = 79) and 49.8% (n = 134), respectively. Fifty-eight patients (21.6%) had major complications and 112 (42%) experienced minor complications. Moreover, 37% of the patients reported multiple complications. A total of 91 intraoperative events were reported. Dural tear was the most common intraoperative complication, accounting for 53% of all reported events. Previous spine surgery (adjusted OR: 3.6; 95% CI: 1.8–7.2) was found to be associated with intraoperative events in multivariate risk analysis. For major postoperative complications, a total of 79 cases were reported. Of these, 32% of the cases were respiratory complications, followed by loss of correction and implant failure, which accounted for 25% of the cases. Diabetes (OR: 3.8; 95% CI: 1.3–10.8) and lung disease (OR: 3.1; 95% CI: 1.0–9.4) were significant risk factors for major complications. There were a total of 206 incidences of minor postoperative complications. Fifteen percent of the cases were urinary tract infections. Twenty-five patients (9.2%) also reported new onset or worsening back or lower extremity pain after surgery, accounting for 12% of all minor complications. Previous spine surgery was the most significant risk factor for minor complications (OR: 3.0; 95% CI: 1.5–6.3). Other significant contributors included age (OR: 1.03), female gender (OR: 2.7), and duration of surgery (OR: 0.99) (p < 0.05). CONCLUSION: To the best of our knowledge, this is the first and largest prospective study in the world to systematically address non-neurological complications of spine deformity surgery in adults. Our findings contribute to a complete “risk profile” of such patients.