Guillermo J. Ares, MD

Attending Physician, Pediatric Surgery; Member, Lurie Children's Surgical Foundation

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Guillermo Ares is a pediatric surgeon with a special interest in minimally invasive and robotic surgery, adolescent bariatric surgery, pediatric surgical oncology, necrotizing enterocolitis, and chest wall deformities. He also treats newborns with a variety of congenital and acquired conditions including tracheoesophageal fistulas, congenital diaphragmatic hernias, intestinal atresias, chest and abdominal wall defects, hernias, and anorectal malformations.

Dr. Ares co-manages a specialized, multidisciplinary bariatric surgery program for adolescents with obesity and a range of obesity-related comorbidities – the first MBSAQIP accredited adolescent bariatric program in Illinois. The program offers progressive structuring for habit formation leading to healthier lifestyles, incorporating surgical intervention in the toolkit for weight loss and subsequent long-term follow up.

Dr. Ares devoted his academic time to the study of the pathophysiology of necrotizing enterocolitis and the biochemical pathways implicated in this disease of the newborn. He developed a multicellular model for the study of NEC using intestinal pluripotent stem cells.

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Clinical Interests

Robotic surgery, adolescent bariatric surgery program, sarcoma program, and chest wall deformities program


Education & Training

Education: Washington University School of Medicine, St. Louis, MO, 2013

Postgraduate Training: Fellowship in pediatric surgery, Northwestern University Feinberg School of Medicine, 2020-2022; Residency in general surgery, University of Illinois College of Medicine , 2013-2020

Board Certifications: American Board of Surgery - General Surgery

Professional Organizations: American College of Surgeons, American Pediatric Surgical Association

Research & Publications