Visceral fat volume from standard preoperative ct is an independent predictor of short-term survival in patients undergoing surgery for metastatic spine disease

Study Design:This is a retrospective cohort.Objective:Determine the relationship of body morphometry to postoperative survival in patients with vertebral metastases.Summary of Background Data:Most operations for vertebral metastases aim for palliation not cure yet expected patient survival heavily influences treatment plans. We seek to demonstrate that preoperative fat and muscle volumes on standard-of-care computed tomography (CT) are independent predictors of survival after surgery for vertebral metastases.Materials and Methods:Included data were preoperative neurological status adjuvant treatments CT-assessed body composition health comorbidities details of oncologic disease and Tomita and Tokuhashi scores. Body composition - visceral fat area subcutaneous fat area and total muscle area - were assessed on preoperative L3/4 CT slice with Image J software. Multivariable logistic regressions were used to determine independent predictors of 3- 6- and 12-month survival.Results:We included 75 patients (median age 57 57.3% male 66.7% white) with the most common primary lesions being lung (17.3%) prostate (14.7%) colorectal (12.0%) breast (10.7%) and kidney (9.3%). The only independent predictor of 3-month survival was visceral fat area [95% confidence interval (CI): 1.02-1.23 per 1000 mm2; P=0.02]. Independent predictors of survival at 6 months were body mass index (95% CI: 1.04-1.35 per kg/m2; P=0.009) Karnofsky performance status (95% CI: 1.00-1.15; P<0.05) modified Charlson Comorbidity Index (95% CI: 1.11-7.91; P=0.03) and postoperative chemotherapy use (95% CI: 1.13-4.71; P=0.02). Independent predictors of 12-month survival were kidney primary pathology (95% CI: 0.00-0.00; P<0.01) body mass index (95% CI: 1.03-1.39 per kg/m2; P=0.02) and being ambulatory preoperatively (95% CI: 1.28-17.06; P=0.02).Conclusions:Visceral fat mass was an independent positive predictor of short-term postoperative survival in patients treated for vertebral metastases. As a result we believe that the prognostic accuracy of current predictors may be improved by the addition of visceral fat volume as a risk factor.