Total Psoas Area is a Measure for Deconditioning in Colorectal Surgery Patients

Introduction: Physical fitness is an important prognostic indicator for surgical outcomes. An objective measure of deconditioning is needed to determine patient fitness. This study aims to describe a methodology to standardize psoas measurements and correlate them with postoperative outcomes. Methods: After obtaining IRB approval, the ACS-NSQIP database was queried for patients over 18 years, undergoing colectomies for non-trauma indications from 1/1/2013 to 12/31/2018. Upon CT imaging, the psoas muscle was identified at the lumbosacral joint. Imaging software calculated the total cross-sectional area of the left and right psoas muscle and was normalized by dividing by height squared to achieve our Total Psoas Index (TPI) in cm²/m². Results: 1173 patients met study criteria; all had TPI calculated. A TPI equal to or below the gender-specific 25th percentile defined sarcopenia. In total, 151 females (24.6%) and 137 males (24.5%) were classified as sarcopenic. TPI was significantly associated with multiple NSQIP 30-day outcomes and mortality in our study population. Conclusions: Measuring TPI at the lumbosacral joint is an appropriate method for determining sarcopenia.