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About Us

About General Surgical Associates, Inc.

General Surgical Associates, Inc. (formerly Charles H. Cook, M.D., Inc.) has served the Lancaster community since 1975. Charles H. Cook, M.D. founded the practice, and he practiced solo for 24 years.

In 1999, Jeffery K. Yenchar, M.D. joined Dr. Cook; and, in 2004, David J. Robertson, M.D., F.A.C.S. joined the practice. Dr. Cook retired in December 2004.

In 2009, Margaret S. Sawyer, M.D., M.B.A. joined General Surgical Associates, Inc.

Providing you with the best doctors for the best care

Jefferey K. Yenchar, M.D., F.A.C.S.

Dr. Yenchar is certified by the American Board of Surgery, a fellow of the American College of Surgeons; a member of the Fairfield County Medical Society, the Ohio State Medical Association, and the Ohio Chapter of the American College of Surgeons. He is also affiliated with Fairfield Medical Center.

David J. Robertson, M.D., F.A.C.S.

Dr. Robertson is a member of American College of Surgeons, Zollinger Surgical Society, Fairfield County Medical Society, The Ohio State Medical Association, American Medical Association, and Society of Laparoendoscopic Surgeons. He is also certified by the American Board of Surgery. He is affiliated with Fairfield Medical Center.

Margaret S. Sawyer, M.D., M.B.A.

Dr. Sawyer is a member of The American Medical Association, The Ohio State Medical Association, American College of Surgeons, American Society of Breast Surgeons, Society of American Gastrointestinal and Endoscopic Surgeons and the Zollinger Surgical Society. She is also certified by the American Board of Surgery. She is affiliated with Fairfield Medical Center.

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