How Giffords Survived

The bullet, reportedly fired from a 9 mm semi-automatic handgun, entered the left side of the back of her head and traveled through her brain, exiting through her forehead. This “through and through” course indicates that the bullet was probably not of the variety designed to expand or break into smaller fragments once inside the body, which would have caused a much more severe injury.

As the projectile moved forward, it remained in the left hemisphere, avoiding crossing through the middle to the other side, which, according to Black, could have caused catastrophic injury. The bullet’s trajectory was also high enough to apparently avoid certain crucial structures on the left side of the brain, including areas responsible for language processing—a notion reinforced by reports that the Congresswoman has been responsive to commands.

Immediately following the injury, it was not only the quality but also the speed of the care Giffords received that probably saved her life. “As we say in neurosurgery,” says Black, “time is brain.” Crucially, one of Giffords’ aides positioned her so that blood did not impede her breathing. Subsequent transport to the Level 1 trauma center at Tuscon’s University Medical Center, and the care given once she arrived, was very rapid. Reportedly, only 38 minutes transpired between the time she was injured and when she entered surgery.

Brain injuries are complex, and it is too early to know definitively the extent to which Giffords will ultimately be set back, or if she can make a full recovery.

A bullet first destroys tissue that lies in its path, which for Giffords was on the left side of the brain. But it also damages neurons that don't lie directly in its path, because it is trailed by a pressure wave that transfers the energy of the bullet into the surrounding brain tissue.

This pressure wave activates all the neurons through which it passes. The neurons then attempt to restore their resting electrochemical balance by absorbing water, resulting in brain swelling. The restoration also takes an enormous amount of energy — more than the injured brain can provide — and so creates an 'energy crisis', or energy deficit in the brain.

Giffords's doctors are addressing these complications by removing a portion of her skull to relieve the pressure of her swelling brain, and by inducing a medical coma to reduce the brain's energy demands.

Some of the recovery is attributable to rewiring of the brain. Neurons that did not die during the injury sprout new connections, attempting to regain their functions and take over functions that may have been lost by neurons that did die. Patients also learn to compensate for lost abilities — for instance, by brushing their teeth with their left hands if they can no longer do so with their right. However, Giffords faces a special challenge because she is a woman. "Women tend to have a more protracted and less complete recovery than men, for reasons that nobody clearly understands," says O'Shanick.