"Mr. Michaels was indeed a lucky person, a very lucky person," Dr. Joseph Zabramski said at a press conference Tuesday at the Barrow Neurological Institute at St. Joseph's Hospital in Phoenix, where the rocker had been receiving treatment.
Michaels, 47, was discharged recently, less than two weeks after suffering a brain hemorrhage April 21. Zabramski could not release details of when he left the hospital or where he's receiving additional treatment because of federal privacy laws.
"He's improving," says Zabramski. "I really expect that he will fortunately make a 100 percent recovery. He's just one of those lucky people – 10 to 20 percent who make a complete recovery and can resume all of their normal activities."
Zabramski, a neurosurgeon at Barrow, one of the country's top brain surgery facilities, said Michaels's medical team will continue to monitor his vital signs and neurological status "very closely" for the next few weeks while he also receives physical therapy.
Shows Determination"He's still very sick right now [but] he's a very determined person," Zabramski, who previously praised Michaels's "sheer will to live", told reporters, adding that he is walking on his own and "his level of consciousness [has] returned to what we call normal."
When Michaels was rushed to the intensive care unit April 22, Zabramski said the singer, whom he described as lethargic and having slurred speech, underwent a CAT scan and two angiograms to check for the source of bleeding, though he did not need to have an operation.
Based on the tests, "We're pretty confident he does not have an aneurysm or other problems with his blood vessels that could result in a recurrent hemorrhage," said Zabramski.
In addition to the side-effect hyponatremia, which can lead to seizures (Michaels's doctor said he has not had any), the rocker has been suffering from back pain and increased spasms – because as a diabetic, he has not been able to take certain medications.
Zabramski said doctors will usually give patients steroids to lessen the pain but they can also "make glucose levels go out of control so unfortunately [Bret has] had to suffer."
Before leaving the hospital, the Poison frontman – whose signature style includes bandanas – received another head piece to add to his collection. His medical team gave him a signed dark blue head scarf with the Barrow logo, a hospital spokesperson tells PEOPLE.
And while Michaels competed on Celebrity Apprentice to raise money for the American Diabetes Association, the lifelong Type 1 diabetic now has another cause: Serving on the Barrow Brain Tumor Research Center's advisory board.
The singer told the foundation he has had passion for brain research after a relative suffered from a fatal brain tumor.
Reporting by ANNE MARIE CRUZ