HOUSTON — Experts say the surgery to repair Arizona Rep. Gabrielle Giffords’ skull is a key step in her recovery and will improve her quality of life.

People with knowledge of her care have told The Associated Press that Giffords is undergoing surgery today. Doctors are placing a plastic implant under her scalp where her skull was removed after she was shot in January.

The surgery is taking place while Giffords’ husband commands the space shuttle Endeavour’s mission to the International Space Station.

Vanderbilt University neurosurgeon Dr. Reid Thompson says there is a 1 percent risk of infection or bleeding, but no risk great enough to wait for Kelly to return.

University of Pittsburgh Medical Center neurosurgeon Dr. Robert Friedlander says the surgery is a “significant milestone” in Giffords’ recovery.