A rare brain surgery performed in San Antonio helped a 15-month-old baby stop having seizures that were by a rare health condition.

When little Reagan Cross was only a year old, she underwent brain surgery after six to eight months of suffering 200 seizures a day.

"During her workup, we discovered that she had a congenital condition called Hemimegalencephaly. That's where one half of the brain, the hemisphere, is very abnormal," Christus Children's Hospital Chief of Pediatric Neurosurgery Mark Lee said.

Worse yet, this congenital condition, called Cortical Dysplasia, caused the right side of her brain to stop functioning at all.

"The potential to control the seizures is actually a very dramatic operation called a hemispherectomy," Lee said.

In the old days, doctors would have removed the entire damaged half of the brain.

"Currently, with newer technologies, we actually go in through much smaller opening and disconnect that whole half of the brain, so it's still there, that abnormal hemisphere, but it's not connected to her," Lee said.

Lee says this newer surgery paves the way to a faster recovery, and there is much less blood loss. Most exciting, was what happened post-surgery.

"She immediately stopped having seizures," Lee said.

Finally, with this surgery, there is less risk of the child getting water on the brain and requiring a shunt. The five-hour surgery gave Reagan and her family new life.

Anti-seizure meds were not effective in the long run, and the dramatic surgery was the recommended choice.

Lee made an incision in the head like a reverse question mark and created a window in the bone, to repair the brain lobe.

Reagan is now three years old and healthy.