Sarcopenia Predicts Perioperative Adverse Events Following Complex Revision Surgery for the Thoracolumbar Spine

Abstract Background Context Sarcopenia measured by psoas muscle index (PMI) has been shown to predict perioperative mortality and adverse events (AEs) after various surgical procedures. However, this relationship has not been studied in complex revision thoracolumbar spine surgery. Purpose This study aimed to determine the relationship between sarcopenia and perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery. Study Design Retrospective cohort study Patient Sample A retrospective analysis was performed at a single institution between May 2016 and February 2020 of patients undergoing complex revision thoracolumbar spine surgery by three board certified fellowship-trained orthopaedic spine surgeons. Outcome Measures Perioperative adverse events including post-operative anemia requiring transfusion, cardiac complication, sepsis, wound complication, delirium, intra-operative dural tear, acute kidney injury, pneumonia, urinary tract infection, urinary retention, epidural hematoma, and deep vein thrombosis. Secondary outcome measures were 30-day readmission rates, 30-day re-operation rates, in-hospital mortality rates, discharge disposition, and post-operative length of stay (LOS). Methods Sarcopenia was analyzed using PMI, calculated at the L3 vertebral body measured on pre-operative magnetic resonance imaging (MRI) or computed tomography (CT) normalized to height [2] (mm2/m2). Receiver operating characteristic (ROC) curve analysis and Youden index were used to determine gender-specific PMI cut-off values for predicting perioperative AEs. Sarcopenia was defined as PMI below the cut-off values. Complex revision surgery was defined as Spine Surgical Invasiveness Index > 10. Results 114 consecutive patients were included in the study. ROC curve analysis demonstrated PMI Conclusions Sarcopenia measured by PMI is associated with higher perioperative AEs, 30-day readmission rates, 30-day re-operation rates, rate of discharge to a facility, and longer LOS among patients undergoing complex revision thoracolumbar spine surgery.