Effect of Sarcopenia on Postoperative Morbidity and Mortality After Thoracolumbar Spine Surgery.

Sarcopenia is the loss of muscle mass associated with aging and advanced disease. This study retrospectively examined patients older than 55 years (N=46) who underwent thoracolumbar spine surgery between 2003 and 2015. Each patient's comorbidity burden was determined using the Charlson Comorbidity Index, and the Mirza Surgical Invasiveness Index was used to measure procedural complexity. Sarcopenia was diagnosed by measuring the total cross-sectional area of the psoas muscle at the L4 vertebrae using perioperative computed tomography scans. Of the 46 patients assessed, 16 were in the lowest third for L4 total psoas area (sarcopenic). Average follow-up time was 5.2 years (range, 6 days to 12.7 years). The cohort of patients with sarcopenia was significantly older than the cohort without sarcopenia (mean age, 76.4 vs 69.9 years; P=.01) but did not have a significantly different mean Charlson Comorbidity Index (3.3 vs 2.0; P=.32) or mean Mirza Surgical Invasiveness Index (7.1 vs 7.0; P=.49). Patients with sarcopenia had a hospital length of stay 1.7-fold longer than those without sarcopenia (8.1 vs 4.7 days; P=.02) and a 3-fold increase in postoperative in-hospital complications (1.2 vs 0.4; P=.02), and they were more likely to require discharge to a rehabilitation or nursing facility (81.2% vs 43.3%; P=.006). Patients with sarcopenia had a significantly lower cumulative survival (log rank=0.007). All 4 deaths occurred among patients with sarcopenia. Patients with sarcopenia have a significantly increased risk of in-hospital complications, longer length of stay, increased rates of discharge to rehabilitation facilities, and increased mortality following thoracolumbar spinal surgery, making sarcopenia a useful perioperative risk stratification tool. [Orthopedics. 2016; 39(6):e1159-e1164.].