Daniel A. Ruge, 88, a neurosurgeon tapped to be White House physician to Ronald Reagan during his first administration, died Aug. 30 at his home in Denver. He had a ruptured abdominal aortic aneurysm.

An expert on spinal cord injuries, Dr. Ruge (pronounced Roog-ee) practiced medicine early in his career with first lady Nancy Reagan's stepfather, Dr. Loyal Davis, in Chicago. Nancy Reagan's stepbrother Richard Davis, also a neurosurgeon, was at one time Dr. Ruge's resident.

Before his appointment to the White House in 1981, Dr. Ruge was chief of the Veterans Administration Spinal Cord Injury Service in Washington.

His selection broke the tradition of having a military physician, preferably one who specialized in surgery or internal medicine, serve as the president's personal doctor. Dr. Ruge replaced Rear Adm. William M. Lukash, who had served 14 years and four presidents.

Dr. Ruge served four years. After the 1981 assassination attempt on Reagan, Dr. Ruge had a role in providing updates, usually sunny, on the president's health. He remained at Reagan's side as the president recovered from the shooting and helped oversee his overall care.

Daniel August Ruge, the son of farmers, was a native of Murdock, Neb., and a 1939 graduate of North Central College in Naperville, Ill.

He was a 1945 graduate of the medical school at Northwestern University and also received master's and doctorate degrees in surgery from the university. He became a professor of surgery at Northwestern.

In his last year of medical school, he did clerical work for Davis, a Northwestern professor, and later was his medical partner. They practiced at Northwestern Memorial Hospital, where Dr. Ruge became chief of staff and chairman of neurosurgery.

Dr. Ruge also had an affiliation with a series of VA hospitals, and he began working at the VA in Washington in 1976.

At the White House, he developed a comfortable and jocular rapport with the president. A chief trait was discretion.

"We had a little game going," Dr. Ruge told the New York Times. "When I wanted to watch him in the hall, I would keep the door of my office ajar. But when I stood outside on the carpet as he passed by in the morning, he knew he should stop by when returning to the residence for an allergy shot or something else."

For all his seeming prominence as the caretaker of the leader of the free world, Dr. Ruge said appearances were deceiving. In the White House directory, he was listed between the chief usher and curator of White House artifacts.

He told the Times bluntly that his role was "vastly overrated, boring and not medically challenging."

He was a founding member and director of the American Spinal Cord Injury Association.

His scholarly writing included two books on spinal cord injuries.

Survivors include his wife of 63 years, Greta Piper Ruge of Denver; two children; two sisters; and two grandchildren.

Daniel Ruge was appointed in 1981 as President Reagan's physician.