The two were supposed to sit next to one another as a show of bipartisanship during this week's State of the Union address.
Kirk's doctor says he had another medical procedure this week to remove two small pieces of brain tissue destroyed by the stroke Kirk suffered last weekend.
Dr. Richard Fessler says the relatively common procedure creates more space around the brain to accommodate expected swelling. Fessler says the senator is alert and gave a thumbs-up when asked to during an examination.