Psoas Muscle Index as a Predictor of Perioperative Outcomes in Geriatric Patients Undergoing Spine Surgery.

Study Design: Single-center retrospective study.

Objective: The objective of this study was to evaluate the association of psoas muscle mass defined sarcopenia with perioperative outcomes in geriatric patients undergoing elective spine surgery.

Methods: We included geriatric patients undergoing thoracolumbar spinal surgery. Total psoas surface area (TPA) was measured on preoperative axial computerized tomography or magnetic resonance imaging at the L3 vertebra and normalized to the L3 vertebral body area. Patients were divided into quartiles by normalized TPA, and the fourth quartile (Q4) was compared to quartiles 1-3 (Q1-3). Outcomes included perioperative transfusions, length of stay (LOS), delirium, pseudoarthrosis, readmission, discharge disposition, revision surgery, and mortality.

Results: Of the patients who met inclusion criteria (n = 196), the average age was 73.4 y, with 48 patients in Q4 and 148 patients in Q1-3. Q4 normalized TPA cut-off was <1.05. Differences in Q4 preoperative characteristics included significantly lower body mass index, baseline creatinine, and a greater proportion of females (Table 1). Q4 patients received significantly more postoperative red blood cell and platelet transfusions and had longer ICU LOS ( < .05; Table 2). There was no difference in intraoperative transfusion volumes, delirium, initiation of walking, discharge disposition, readmission, pseudoarthrosis, or revision surgery (Tables 2 and 3). Mortality during follow-up was higher in Q4 but was not statistically significant ( = .075).

Conclusion: Preoperative TPA in geriatric patients undergoing elective spine surgery is associated with increased need for intensive care and postoperative blood transfusion. Preoperative normalized TPA is a convenient measurement and could be included in geriatric preoperative risk assessment algorithms.