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

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.

This study aimed to determine the relationship between sarcopenia and perioperative AEs among patients undergoing complex revision thoracolumbar spine surgery.

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.

Perioperative adverse events including postoperative 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 postoperative length of stay (LOS).

Sarcopenia was analyzed using PMI, calculated at the L3 vertebral body measured on preoperative magnetic resonance imaging (MRI) or computed tomography (CT) normalized to height² (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.

A total of 114 consecutive patients were included in the study. ROC curve analysis demonstrated PMI <500 mm²/m² for males and <412 mm²/m² for females as predictors for perioperative AEs. 49 patients were in the sarcopenia cohort and 65 patients in the nonsarcopenia cohort. The sarcopenia group had higher overall perioperative AEs (75.5% vs 27.7%, p<.001) and individual AEs including: postoperative anemia requiring transfusion, wound complication, delirium, acute kidney injury, pneumonia, urinary tract infection, and deep vein thrombosis. The sarcopenia group had higher 30-day reoperation rate (14.3% vs 3.1%, p=.037), 30-day readmission rate (16.3% vs 3.1%, p=.018), rate of discharge to a facility (83.7% vs 50.8%, p<.001), and longer length of stay (LOS) (7.3±4.2 days vs 5.6±3.5 days, p=.023).

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 longer LOS among patients undergoing complex revision thoracolumbar spine surgery.