Reduced paraspinous muscle area is associated with post-colectomy complications in children with ulcerative colitis.

Sarcopenia, defined as reduced muscle mass, is typically assessed by CT scans, which are infrequently performed in children. Using MRI to measure sarcopenia, we determined the association with postoperative complications after colectomy for ulcerative colitis (UC).Clinical and preoperative MRI data for 13-18-year-old UC patients who underwent colectomy were retrospectively reviewed. Bilateral paraspinous muscle area (PSMA) and psoas muscle area (PMA) at L3 vertebra were measured and averaged. Composite complications were infection, wound dehiscence, postoperative leak/abscess, prolonged ileus, pulmonary embolism, venous thromboembolism, or readmission.Twenty-nine patients with average age 15.9±1.36years and weight 61.5±19.8kg had a preoperative MRI. The 18/29(62%) with complications had significantly reduced PSMA (4.71±1.44 vs 5.64±1.38cm2, p=0.04) and PMA (7.16±2.60 vs 8.93±2.44, p=0.04). When stratified and compared to highest PSMA, patients with lowest PSMA had increased complication rates (88% vs 29%, p=0.04). There were no differences in age, BMI, albumin, CRP, ESR, or preoperative steroid or anti-TNFα use. Odds of complication in the lowest tertile were 25.0-fold higher than the highest tertile (p=0.04, 95% CI=1.2-520.73).This is the first study to show low PSMA on MRI is associated with complications and increased hospital stay after colectomy in children with UC.Level III retrospective comparative study.