Risk factors for surgery-related muscle quantity and muscle quality loss and their impact on outcome

Background Surgery-related loss of muscle quantity negatively affects postoperative outcomes. However, changes of muscle quality have not been fully investigated. A perioperative intervention targeting identified risk factors could improve postoperative outcome. This study investigated risk factors for surgery-related loss of muscle quantity and quality and outcomes after liver resection for colorectal liver metastasis (CRLM). Methods Data of patients diagnosed with CRLM who underwent liver resection between 2006 and 2016 were analysed. Muscle quantity (psoas muscle index [PMI]), and muscle quality, (average muscle radiation attenuation [AMA] of the psoas), were measured using computed tomography. Changes in PMI and AMA of psoas after surgery were assessed. Results A total of 128 patients were analysed; 67 (52%) had surgery-related loss of muscle quantity and 83 (65%) muscle quality loss. Chronic obstructive pulmonary disease (COPD) (P = 0.045) and diabetes (P = 0.003) were risk factors for surgery-related loss of muscle quantity. A higher age (P = 0.002), open resection (P = 0.003) and longer operation time (P = 0.033) were associated with muscle quality loss. Overall survival was lower in patients with both muscle quantity and quality loss compared to other categories (P = 0.049). The rate of postoperative complications was significantly higher in the group with surgery-related loss of muscle quality. Conclusions Risk factors for surgery-related muscle loss were identified. Overall survival was lowest in patients with both muscle quantity and quality loss. Complication rate was higher in patients with surgery-related loss of muscle quality.