Best Frailty Index In Thoracolumbar Deformity Surgery And Risk Factors Associated With Complications

Introduction: Thoracolumbar adult deformity surgery (ASD) is associated with increased rates of medical and surgical complications. Although several frailty indexes have been described and applied in patient cohorts undergoing complex spine surgery, there is a notable absence of direct comparisons between them. We aim to determine the most appropriate frailty index to predict early complications (three months after surgery) after thoracolumbar spine surgery and characterize complication risk factors.

Methods: Retrospective analysis of consecutive patients from a tertiary center who underwent thoracolumbar ASD surgery involving 7 or more levels, patients were categorized based on the following frailty indexes: mFI-11, mF-5, mF-19, ASD-F1, and CD-F1. Subsequently, patients were further analyzed based on whether they experienced complications or not. Both univariate and regression analyses were performed.

Results: A total of 231 patients were included in the analysis. The mean age of the patients was 67.77±12.2 years, and the mean number of levels fused was 9.3±3.2. Frailty scores means were: mFI-11 (0.17±0.14), mF-5 (0.22±0.17), mF-19 (0.13±0.09), ASD-F1 (0.27±0.16), and CD-F1 (0.24±1.32). The best predictor of complications after ASD surgery was CD-F1, with an area under the ROC curve of 0.618. Among the patients, 83 (35.9%) experienced complications. Those who experienced complications had longer fusions (10±3.6 vs 8.87±2.9 levels, p=0.008). Additionally, their mF-5, mF-19, ASD-F1, and CD-F1 scores were significantly higher than those without complications (p < 0.05).
Patients reporting feeling worn out most of the time (p=0.009), having poor general health (p=0.032), not being in excellent health (p=0.004), or having an unsteady gait (p=0.024) were more likely to experience complications in the univariate analysis. In the regression analysis, complications-related factors included age above 80 years (OR 4.8, 95% CI 1.33-17.465, p=0.016) and diabetes (OR 3.73, 95% CI 1.38-10.1, p=0.009).

Conclusion : The best available frailty score to determine complications after thoracolumbar ASD surgery is CD-F1, additionally, patients aged above 80 years old and those with diabetes have higher odds of experiencing complications following ASD surgery.