Perioperative changes in trunk musculature and postoperative outcomes

Surgeons often face difficult decisions in selecting which patients can tolerate major surgical procedures. Although recent studies suggest the potential for trunk muscle size, as measured on preoperative imaging, to inform surgical risk, these measures are static and do not account for the effect of the surgery itself. We hypothesize that trunk muscle size will show dynamic changes over the perioperative period, and this change correlates with postoperative mortality risk.

A total of 425 patients who underwent inpatient general surgery were identified to have both a 90-d preoperative and a 90-d postoperative abdominal computed tomography scan. The change in trunk muscle size was calculated using analytic morphomic techniques. The primary outcome was 1-y survival. Covariate-adjusted outcomes were assessed using multivariable logistic regression.

A total of 82.6% patients (n = 351) experienced a decrease in trunk muscle size in the time between their scans (average 62.1 d). When stratifying patients into tertiles of rate of change in trunk muscle size and adjusting for other covariates, patients in the tertile of the greatest rate loss had significantly increased risk of 1-y mortality than those in the tertile of the least rate loss (P = 0.002; odds ratio = 3.40 95% confidence interval, 1.55-7.47). The adjusted mortality rate for the tertile of the greatest rate loss was 24.0% compared with 13.3% for the tertile of the least decrease.

Trunk muscle size changes rapidly in the perioperative period and correlates with mortality. Trunk muscle size may be a critical target for interventional programs focusing on perioperative optimization of the surgical patient.