Meet Our Practitioners

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Donald B. Colvin, MD, FACS, FASCRS

Donald B. Colvin, MD, FACS, FASCRS

Fairfax / Alexandria
Dr. Colvin received both Bachelor’s and Doctor of Medicine degrees from the University of Florida in Gainesville.
Lawrence E. Stern, MD, FACS, FASCRS

Lawrence E. Stern, MD, FACS, FASCRS

Fairfax / Alexandria / Reston
Dr. Stern’s first entry into the field of medicine was at age 16, as an Emergency Medical Technician. He enjoyed helping people in need and had the desire to do more for them.
Caroline Sanchez, MD, FACS, FASCRS

Caroline Sanchez, MD, FACS, FASCRS

Fairfax / Alexandria
Dr. Sanchez has wanted to be a doctor her entire life. She is a native of Northern Virginia and attended the prestigious Thomas Jefferson High School for Science and Technology.
Katherine W. Khalifeh, MD, FACS, FASCRS

Katherine W. Khalifeh, MD, FACS, FASCRS

Fairfax / Reston / Loudoun
Dr. Khalifeh has a unique perspective on patient care and treatment, having first been a critical care nurse before taking on the challenge of graduating
Timothy A. Plerhoples, MD, MPH, FASCRS

Timothy A. Plerhoples, MD, MPH, FASCRS

Fairfax / Reston / Loudoun
Dr. Plerhoples earned his Bachelor’s degree from Harvard University and trained with world-renowned colorectal surgeons at Stanford University and the Mayo Clinic.
Christina Cheng, MD

Christina Cheng, MD

Fairfax / Reston / Alexandria
Dr. Cheng was motivated to become a doctor at the age of twelve after her father passed away from terminal cancer.
John Tillou, MD

John Tillou, MD

Fairfax / Fair Oaks / Reston / Loudoun
Dr. Tillou has always had a passion for solving complex problems. He was inspired to become a surgeon after undergoing an operation in high school and learning the science behind his procedure.
Elizabeth K. York, PA-C

Elizabeth K. York, PA-C

Fairfax
Ms. York earned her Bachelor’s degree in Biology from Boston College and earned her Master’s degree in Health Sciences as a Physician Assistant at George Washington University.