Cross-sectional area of the abdomen predicts complication incidence in patients undergoing sternal reconstruction

Abstract

Background: Sternal reconstruction with vascularized flaps is central to the management of sternal wound infections and mediastinitis but carries a high risk of complications. There is a need to identify reliable predictors of complication risk to help inform patients and clinicians in preparation for surgery. Unfortunately, body mass index and serum albumin may not be reliable predictors of complication rates. Analytic morphomics provides a robust quantitative method to measure patients' obesity as it pertains to their risk of complications in undergoing sternal reconstruction.

Methods: We identified 34 patients with preoperative computed tomography scans of the abdomen from a cohort of sternal reconstructions performed between 1997 and 2010. Using semiautomated analytic morphomics, we identified the patients' skin and fascia layers between the ninth and 12th thoracic spine levels; from these landmarks, we calculated morphomic measurements of the patients' abdomens, including their total body cross sectional area and the cross sectional area of their subcutaneous fat. We obtained the incidence of complications from chart review and correlated the incidence of complications (including seroma, hematoma, recurrent wounds, mediastinitis, tracheostomy, and death) with patients' morphomic measurements.

Results: Sixty-two percent of patients (n = 21) suffered complications after their operation. Those who suffered from complications, relative to those who did not have complications, had increased visceral fat area (12,547.2 mm(2)versus 6569.9 mm(2), P = 0.0080), subcutaneous fat area (16,520.2 mm(2)versus 8020.1 mm(2), P = 0.0036), total body area (91,028.6 mm(2)versus 67,506.5 mm(2), P = 0.0022), fascia area (69,238.4 mm(2)versus 56,730.9 mm(2), P = 0.0118), total body circumference (1101.8 mm versus 950.2 mm, P = 0.0017), and fascia circumference (967.5 mm versus 868.1 mm, P = 0.0077). We also demonstrated a significant positive correlation between the previously mentioned morphomic measurements and the incidence of complications in multivariate logistic regression models, with odds ratios ranging from 1.19-3.10 (P values ranging from 0.010-0.022).

Conclusions: Increases in abdominal morphomic measurements correlate strongly with the incidence of complications in patients undergoing sternal reconstruction. This finding may influence preoperative risk stratification and surgical decision making in this patient population.

Keywords: Morphomics; Sternal reconstruction; Subcutaneous fat.