May 18, 2011— -- The operation to replace a piece of Rep. Gabrielle Giffords' skull was an important and necessary step in her recovery, neurosurgeons told ABC News Wednesday.
But the surgery is not without risks, doctors say.
Doctors at Memorial Hospital in Houston performed the surgery Wednesday morning, more than four months after the shooting in Tucson, Ariz., that left six dead and 13, including Giffords, injured.
The injury Giffords sustained when she was shot in the head led to brain swelling -- an emergency that necessitated the removal of a portion of her skull to relieve pressure.
"Because the skull forms a closed box, the removal of a large portion of it allows the brain to swell outward instead of inward, said Dr. Nicholas Boulis, assistant professor of neurosurgery at Emory University Hospital in Atlanta. "Swelling inward can crush important deep brain structures, leading to death or permanent coma."
For some patients, the operation simply replaces the part of the skull that was removed; in Giffords' case, the surgical team, led by Dr. Dong Kim, inserted a plastic replacement that had been custom-designed to fill the space in her skull.
"When a piece of the skull is removed to allow for brain swelling, a surgery called hemicraniectomy, the flap of bone that is removed was once a critical protective plate for the skull," said Dr. Wendy Wright, assistant professor of neurology and neurosurgery at Emory. "After the bone is removed, the skin is closed back over the surgical site with no hard protective plate over the brain. Therefore, if a person were to fall or if anything were to hit their head, the brain could be damaged."
Dr. Charles Liu, chief of neurosurgery at Rancho Los Amigos at the University of Southern California Medical, said complications from the procedure are rare, but they do happen.
"The operation is pretty straightforward, but there are potentially serious risks," Liu said. "These include the formation of a large blood clot beneath the implant -- epidural hematoma -- as well as infection."
Other doctors not involved in Giffords' case agreed that although the operation can come with some minor risks, it is usually a safe one.
"While this is still considered brain surgery, there are much less risks than the initial operation," said Dr. Ricky Madhok, a neurosurgeon at the Cushing Neuroscience Institutes of the North Shore Long Island Jewish Health System in New York. "We still worry about bleeding, strokes, seizures and infections, but the risk is much lower, as we are recreating the contour and the protection offered by the skull and not actually manipulating the brain itself."
Whether the use of a plastic implant is just as good as using the bone itself is another matter for debate. While some surgeons said current materials do the job well, Liu said he is not convinced.
"There are very serious concerns that [surround] any implant to reconstitute the skull," Liu said, adding that such implants "may not truly reconstitute the protective nature of the original skull. ... There is currently very little data about the protective nature of these implants."
Liu is currently leading research designed to tease out the long-term effects, if any, of these implants. Other doctors, however, said current methods do an excellent job of filling the gap left by hemicraniectomy surgery.
"Usually a CT scan is done, and a computer uses the normal opposite side to create an exact model as the missing side -- a mirror image," said Dr. Matthew Ewend, chairman of neurosurgery at the University of North Carolina at Chapel Hill. "The computer then builds a plate out of resins that fits the defect perfectly.
"These are pretty good, and I doubt there are great advances to be made."