Illinois Republican Sen. Mark Kirk suffered a stroke on Saturday and has undergone surgery that his doctor said could lead to physical impairment but perhaps not affect his ability to think or speak.
The surgery, which involved temporarily removing a 4-inch by 8-inch portion of Kirk's skull to relieve pressure on his brain, was declared successful at Northwestern Memorial Hospital in Chicago, according to multiple news reports.
Kirk, 52, remained in intensive care on Monday. His surgeon, Dr. Richard Fessler, wouldn't say how long recovery might take, according to the reports.
Fessler said the stroke was to the right side of Kirk's brain, which affects movement on the left side of his body and could also result in some facial paralysis. He said the stroke did not appear to involve the brain's left side, which could affect Kirk's speech.
Kirk, whose state has the most commercial nuclear power reactors (11 at six sites), has been a leading proponent of resurrecting the Yucca Mountain nuclear waste burial site that has been terminated by the Obama administration.
As the Senate was debating an energy bill in November, Kirk prepared an amendment to restore a small level of funding to the project in order to keep it on life support. But ultimately he backed down after Nevada's senators began mobilizing opposition to it.
Kirk who lives in Highland Park, a suburb north of Chicago, drove himself to a local hospital on Saturday when he began feeling dizzy and having headaches. He was transferred to the city hospital.