University of Minnesota doctor performs brain surgery through a pencil-sized incision

Peter Carvalho wasn't eager to let doctors pop open his cranium to remove a second brain tumor — not after the surgery to remove the first one left him struggling to think and talk for six months.

But this time, a surgeon at the University of Minnesota Medical Center offered new technology that would allow him to reach Carvalho's tumor through a pencil-sized incision and then use high-tech imaging to see inside Carvalho's head during the procedure.

And this time, the 27-year-old Hibbing teacher left the hospital the day after surgery — fully recovered and minus the tumor that had been causing seizures, memory loss, depression and pain.

"Everything improved right away," said Carvalho, who is studying to move to Japan and teach English. "My speech, my pronunciation, my focus … even my Japanese improved."

The brain surgery last month was the first in Minnesota to use a system called ClearPoint, which stabilizes a patient's head during surgery and allows doctors to operate without opening the skull and looking at the brain and tumor directly.

The system, made by California-based MRI Interventions, was federally approved in 2010. Mayo Clinic researchers in Arizona have been studying its use in a treatment of severe and fatal strokes. But it hadn't been used in Minnesota until the U recruited Dr. Clark Chen, who had used the system in California.

In Carvalho's surgery, Chen secured his patient in an MRI, screwed a bracketing system into the top of his skull, and threaded a surgical tool into his patient's brain so that he could burn and kill the tumor.

"I would think of something but I wouldn't be able to articulate it," he recalled. "It would be in my mind, but I wouldn't be able to express how I feel.

"And I forgot my passwords for everything," he added.

By December, the tumor had doubled in size and the need for surgery was apparent. Carvalho said its growth had gradually caused personality changes and depression that led him to attempt suicide last summer. On the other hand, the delay made him the first candidate for Chen's new approach.

Chen said Carvalho's first surgery probably went beyond the tumor and damaged the brain. A major advantage of the MRI-guided approach is identifying the tumor so that surrounding tissue is spared.

"Sometimes, its very difficult to know the boundary between normal brain and tumor," Chen said.