How Can Someone Live with Only Half a Brain?
Hemispherectomies in the New Yorker.
At nine o’clock on July 28th last year, Wendy Nissley carried her two-year-old daughter, Lacy, into O.R. 12 at Johns Hopkins Hospital to have half of her brain removed. Lacy suffered from a rare malformation of the brain, known as hemimegalencephaly, in which one hemisphere grows larger than the other. The condition causes seizures, and Lacy was having so many—up to forty in a day—that, at an age when other toddlers were trying out sentences, she could produce only a few language-like sounds As long as Lacy’s malformed right hemisphere was attached to the rest of her brain, it would prevent her left hemisphere from functioning normally. So Lacy’s parents had brought her to Johns Hopkins for a hemispherectomy, which is probably the most radical procedure in neurosurgery.
Wendy laid her daughter on the operating table. Because Lacy was so small, it took the anesthesiologist almost ninety minutes to insert her intravenous lines. George Jallo, the attending neurosurgeon, spent a long time arranging her head on gel padding and then drew “Cut here” markings on her shaved scalp. The rest of Lacy’s head, including her face, was covered with a sterile drape. Jallo made one long cut across the top of her head from the front to the back, and another at right angles to the first, which started midway along it and stopped just in front of her right ear. He folded back the scalp and made small holes in her skull with a power drill, outlining a rough semicircle. Then he used the drill to connect the dots and removed a portion of the skull. He cut another T in the dura, a thin, leathery membrane covering the brain. Gently, he peeled back two large flaps...