Association Between Two Muscle-Related Parameters and Postoperative Complications in Patients Undergoing Colorectal Tumor Resection Surgery.

Background: This study aimed to investigate the associations of 2 preoperative muscle-related parameters, the third lumbar vertebra skeletal muscle index (L3 SMI) for muscle mass and the Hounsfield unit average calculation (HUAC) for muscle density, with the occurrence of postoperative complications among patients undergoing colorectal tumor resection surgery under general anesthesia. We hypothesized that muscle-related parameters are associated with the occurrence of postoperative complications.

Methods: This was a single-center, retrospective observational study. Adult patients who underwent colorectal tumor resection surgery under general anesthesia between 2018.09.01 and 2021.09.01 were enrolled. The last abdominal computed tomography (CT) scan images obtained within 3 months before surgery were used to calculate the L3 SMI and HUAC. The primary outcome was defined as the occurrence of any postoperative complications corresponding to Clavien-Dindo classification before discharge. The secondary outcome was defined as the occurrence of any severe postoperative complications (Clavien-Dindo grade ≥3) before discharge. Multivariable logistic regression analyses were used to estimate the association between muscle-related parameters and incidence of postoperative complications. Patients' baseline demographics, past medical history and intraoperative parameters were adjusted in the multivariable logistic regression analysis.

Results: A total of 317 patients with a median age of 66 (58-72) years were included. Sarcopenia (muscle mass reduction) patients in our cohort and myosteatosis (muscle density decline) were present in 254 (80.1 %) and 79 (24.9%) patients, respectively. A total of 135 patients (42.6 %) developed postoperative complications. According to the multivariable logistic regression, myosteatosis (odds ratio [OR], 1.8, 95% confidence interval [CI], 1.0-3.3, P = .039) was significantly associated with postoperative complications.

Conclusions: A significant association was observed between myosteatosis and postoperative complications (corresponding to Clavien-Dindo classification before discharge), especially severe postoperative complications (Clavien-Dindo grade ≥3) in patients undergoing colorectal tumor resection. Screening for myosteatosis with HUAC using the CT before surgery may help clinicians identify high-risk perioperative patients early.