By Rob Stein
Washington Post Staff Writer
Monday, June 2, 2008 2:26 PM

The brain surgery that Sen. Edward M. Kennedy (D-Mass.) underwent is an extremely delicate, painstaking procedure but offers him the best hope of extending his survival, several neurosurgeons not involved in his care said today.

"The treatment that has been shown to make the most difference as far as survival is removal of the tumor," said Vivek Deshmukh, director of cerebrovascular and endovascular neurosurgery at George Washington University Medical Center. "Surgical removal carries the greatest benefit in terms of extending his survival."

Even if the surgery and follow-up radiation and chemotherapy go well, however, Kennedy's prognosis remains fairly grim. Most patients survive only about a year, although with surgery, survival can be extended by two or three years and in rare cases even longer.

"It's the only hope you can give for prolonged survival. It's giving the patient and the family hope for greater length of survival you wouldn't otherwise have," Deshmukh said.

To prepare for the surgery, Kennedy would have undergone an MRI brain scan last night to provide neurosurgeon Allan H. Friedman at Duke University Medical Center with a detailed image of the size and location of the tumor, which is in a part of his brain called the left parietal lobe.

This part of the brain is involved in certain aspects of speech, sensation and motor control on the right side of the body, so the decision to operate apparently means surgeons determined they had a good chance of removing a large part of the tumor without causing devastating damage.

"If the tumor is located in a speech or motor area, then surgery is usually not performed," Deshmukh said. "In this case they have made the determination the benefits of the surgery outweigh the risk."

After Kennedy had been anesthetized and a small part of his head shaved, Friedman would made an incision probably about four to six inches long to pull back the scalp and expose the bone, experts familiar with the procedure said. The surgeon would then use a drill to cut a roughly dime-sized hole in the skull in order to insert a second drill bit, shaped like a hockey stick, to cut out a larger piece of bone, probably about three inches in diameter. Friedman would then use a scalpel to cut through the layer of tissue covering the brain, known as the dura.

Before beginning the actual brain surgery--and sometimes during it--the patient would be made conscious so doctors can ask the patient questions to ensure they are not damaging parts of the brain responsible for language.

Friedman would use a high-powered microscope to begin painstakingly cutting into the brain to locate the cancer and remove as much of the tumor tissue as possible, usually using a computer-guided system to help him navigate.

"The computer can tell use precisely where we are on his brain and which direction we need to go to go to his tumor," Deshmukh said.

The cancerous tissue can be excised with several devices, including a tiny scissors-like scalpel and instruments that use heat or high-frequency sound waves to dissolve the tissue and suction it out.

"We remove the tumor by working around the margins of it and separating it from the normal tissue," said Christopher G. Kalhorn, an assistant professor of neurosurgery at Georgetown University Medical Center.

Friedman would remove as much of the tumor as possible, then use heat to stop any bleeding, which is one of the biggest risks from brain surgery. He might also apply a foam-like substance that promotes clotting.

The bone would then be put back, fastened in place with titanium plates and screws, and the scalp would be pulled back over the area.

Kennedy will be kept in intensive care for at least one night and doctors will perform another MRI to determine how much of the tumor they were able to remove. Once he awakes, doctors will also begin assessing whether he suffered neurological damage from the surgery.

"There's a risk of motor sensory deficit on the right side of his body, and there's a potential risk to speech, either to express or understand spoken speech," Kalhorn said.

In addition to bleeding, brain surgery patients also face risks for infections and seizures.

After about a week at Duke, Kennedy plans to return to the Massachusetts General Hospital in Boston for radiation and chemotherapy, which is aimed at killing as much of the remaining tumor as possible.

"These tumors have fingers that infiltrate into other parts of the brain that you can't see on the MRI," Deshmukh said. "You can't physically remove everything. That's what you hope to knock out with the radiation and chemotherapy."