Study Confirms Benefits Of Hemispherectomy Surgery

A new study by Johns Hopkins Children's Center scientists confirms the lasting benefits of hemispherectomy, a dramatic operation in which half the brain is removed to relieve frequent severe seizures that medications cannot control.

Results of the study, published in the Oct. 14 issue of Neurology, show that 86 percent of the 111 children who underwent hemispherectomy at the Children's Center between 1975 and 2001 are either seizure-free or have non-disabling seizures that do not require medication.

These results are slightly improved over a 1997 study of 58 Hopkins hemispherectomy patients which found that 78 percent of children were either seizure-free or had mild seizures.

The findings should help parents who are still contemplating whether their child would benefit from the surgery, said the study's lead author, Eric Kossoff, M.D., a pediatric epileptologist at the Children's Center.

"It's clear now that the quality of life of children with chronic, severe seizures greatly improves following hemispherectomy," he said. "In almost all cases, the children no longer depend on multiple medications, and post-operatively, most of the children are walking and running and living normal lives."

All hemispherectomy patients have partial paralysis on the side of the body opposite the removed portion. However, "except for a few with major postoperative complications, such as meningitis and edema, all the children we followed up with are up and about and most have adapted to their handicapped side so well that they play the piano, golf, ping-pong and can dance," Kossoff added.

In the latest study, Hopkins researchers reviewed the charts and contacted many of the families of the 58 children who participated in the 1997 study, as well as 53 other children who subsequently had a Hopkins hemispherectomy. They found 65 percent are seizure-free, 21 percent have occasional, non-handicapping seizures, and 14 percent have troublesome seizures. Eighty percent of patients no longer use drugs or are taking only one anti-convulsant medication.

The researchers say patients with Rasmussen's syndrome, a rare nervous system disorder characterized by chronic inflammation of the brain, and those with congenital vascular injuries benefit the most from hemispherectomy. Sixty-five percent of Rasmussen's patients and 81 percent of patients with vascular injuries are now seizure-free.

Although children with disorders of brain development (dysplasias) have just a 50/50 chance of being seizure-free following the surgery, even those with persistent seizures after surgery experience a reduction in the number of seizures, Kossoff said.

The surgery, which leaves intact the deep structures of the brain (the thalamus, brain stem and basal ganglia), is performed at Hopkins on children with Rasmussen's syndrome, a variety of developmental abnormalities on one side of the brain, and on those who have had disabling strokes. Because children's brains are "plastic," if surgeons remove the affected portion of the brain, the remaining portion overtakes most of the functions of the missing side.

Hemispherectomy was first attempted in the 1920s by Hopkins neurosurgeon Walter E. Dandy, M.D. It was reintroduced at Hopkins in 1968 and was refined in the 1980s by Benjamin S. Carson, M.D., director of pediatric neurosurgery at the Children's Center and a co-author of the current study.

Additional co-authors are Eileen P.G. Vining, Diana J. Pillas, Paula L. Pyzik, Anthony M. Avellino, and John M. Freeman, all of the department of pediatric neurology and neurosurgery at the Johns Hopkins Children's Center. (Dr. Avellino is now on the faculty at the University of Washington School of Medicine.)