Sarcopenia predicts perioperative adverse events following complex revision surgery for the thoracolumbar spine

•This study investigated the relationship between sarcopenia measured by PMI and AEs among patients undergoing complex revision thoracolumbar spine surgery.•Sarcopenia was analyzed using PMI, which was calculated by the total cross-sectional area of the bilateral psoas muscle at the L3 vertebral body measured on preoperative MRI or CT divided by height2 (mm2/m2).•Sarcopenia measured by PMI is associated with higher perioperative AEs, 30-day readmission rates, 30-day reoperation rates, rate of discharge to a facility, and a longer LOS among patients undergoing complex revision thoracolumbar spine surgery.•The PMI cut-off value for predicting perioperative AEs were