Original ArticleDevelopment of a Metastatic Spinal Tumor Frailty Index (MSTFI) Using a Nationwide Database and Its Association with Inpatient Morbidity, Mortality, and Length of Stay After Spine Surgery

ObjectiveThe aim of this study was to develop a perioperative metastatic spinal tumor frailty index (MSTFI) that could predict morbidity, mortality, and length of stay.MethodsA large inpatient hospitalization database was searched from 2002 to 2011 to identify 4583 patients with spinal metastasis from breast (21.1%), lung (34.1%), thyroid (3.8%), renal (19.9%), and prostate (21.1%) cancer who underwent surgery. A multiple logistic regression model identified 9 independent parameters that were used to construct the MSTFI: anemia, chronic lung disease, coagulopathy, electrolyte abnormalities, pulmonary circulation disorders, renal failure, malnutrition, emergent/urgent admission, and anterior/combined surgical approach. Patients with 0 points were categorized as “not frail,” 1 as “mildly frail,” 2 as “moderately frail,” and ≥3 as “severely frail.”ResultsThe overall perioperative complication rate was 19.3% and in-patient mortality was 3.0%. Compared with patients with no frailty, patients with moderate frailty (odds ratio [OR] 5.15; 95% confidence interval [95% CI] 2.44-10.86), and severe frailty (OR 5.74; 95% CI 2.69-12.24) had significantly increased odds of inpatient mortality (all P < 0.001). Similarly, patients with mild frailty (OR 1.88; 95% CI 1.33-2.66), moderate frailty (OR 3.83; 95% CI 2.71-5.41), and severe frailty (OR 6.97; 95% CI 4.98-9.74) had significantly increased odds of developing a major in-hospital complication (all P < 0.001). Length of stay also increased significantly by MSTFI (P < 0.001).ConclusionsIn surgically treated patients with spinal metastasis, certain perioperative parameters may significantly predict the risk of major in-hospital complications and mortality.