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  • Minimally Invasive Laparoscopic Surgery
  • Colorectal Surgery
  • Robotic Surgery
  • Breast Surgery
  • Surgical Oncology
  • Endoscopic Procedures
  • Anti-reflux Surgery
  • Emergency Trauma Care
  • Diseases of the Thyroid and Parathyroid Glands
  • Vascular Surgery
  • Endovascular Surgery
  • Thoracic Surgery
  • Radiofrequency Ablation for Varicose Veins

Personal Info

Dr. Brennan is a Board Certified General surgeon. He is a graduate of University of Wisconsin Medical School in Madison, Wisconsin, receiving his general surgery and trauma training at Loyola University Medical Center in Maywood, Illinois.

He is a Fellow of the American College of Surgeons, a position that requires devotion to surgical practice and uncompromising adherence to the ethical standards of the College. Fellows must have graduated from a medical school accepted by the College, be certified by the American Board of Medical Specialty, hold an unrestricted medical license to practice, and be a specialist in surgery.


His interests include minimally invasive laparoscopic surgery, robotic surgery, endoscopy, surgical oncology, endocrine surgery, colorectal surgery, thoracic surgery, vascular surgery, endovascular surgery and emergency trauma care.

Education & Training

University of Notre Dame, Notre Dame, IN 1993

Medical School
University of Wisconsin Medical School, Madison, WI 1997

Loyola University Medical Center, Maywood, IL 1997-1998

Loyola University Medical Center, Maywood, IL 1998-2002
Chief Resident, Loyola University Medical Center, Maywood, IL 2002

Licensures & Certifications
  • License, Medicine and Surgery, State of Wisconsin
  • Fellow of the American College of Surgeons
  • Diplomate of the American Board of Surgery
  • Advanced Trauma Life Support Certification
  • Verified Trauma Surgeon – American College of Surgery
Hospital Associations
  • ThedaCare Regional Medical Center – Neenah, Neenah, WI
  • ThedaCare Regional Medical Center – Appleton, Appleton, WI