Lying on the table in Operating Room 22 at Children's Hospital Boston, under a blanket of sterile blue surgical draping, is a 6-year-old girl named Jordyn Cook. Jordyn has had epilepsy since she was 3, and often the seizures are so bad that they won't stop unless she is given a dose of Valium.

She has had seizures while riding in the car, while sitting in the tub, while traveling on an airplane. "There's no set pattern," says her mother, Xan Cook. Jordyn's healthy twin brother is in the first grade this year, but she is repeating kindergarten because of her illness. "It makes me sad, thinking that they're twins and they can't be in the same grade," Xan says.

Jordyn has tried 11 different epilepsy drugs, none of which worked very well. Last fall, she had surgery to remove part of her brain's right temporal lobe, which seemed to be the primary source of her seizures. That helped for a while--but then the seizures came back.

Today, a neurosurgeon named Dr. Joseph R. Madsen will implant a medical device in Jordyn that represents one of the last options for improving her epilepsy and putting her young life back on track. Madsen is the surgeon every parent would choose for her child. He is affable and supremely confident, and he has performed this half-hour procedure about 500 times. Most often, it goes smoothly--but there's no guarantee.

Jordyn is under general anesthesia, her heart beating 88 times per minute. The left side of her chest is exposed, and so is her pale white neck. Madsen takes a blue pen and draws two lines where he will make incisions. One mark is vertical, running about an inch-and-a-quarter up her neck, directly above where Jordyn's carotid artery pulses away. The second, slightly longer, mark also runs vertically, this one near her armpit, close to the place where Jordyn's fingers would touch when she put her hand over her heart to say the Pledge of Allegiance.

The device that will be installed in Jordyn is a small titanium disc called a vagus-nerve stimulator (VNS). It's about the size and thickness of a Chips Ahoy chocolate-chip cookie and costs $15,000. (The total cost of implantation can run from $20,000 to $35,000.) Similar to a pacemaker, it sends out pulses of electricity, but instead of stimulating the heart, it stimulates the vagus nerve, which runs up the neck to the brain. In many patients, the VNS device lessens the frequency and severity of seizures. It is not a miracle cure for epilepsy, but as Xan says, "We're just trying to give Jordyn the best quality of life that she can have."

The company that makes the VNS device, Cyberonics Inc., headquartered in Houston, traveled a rocky path toward getting the device approved and then getting neurologists to accept it as a viable treatment for epilepsy--which had previously been treated only with drugs or brain surgery. Over the course of its 16-year life, the company has coped with disappointing data from clinical trials, a newly hired CEO who quit after a week, potential acquirers who walked away at the eleventh hour, rejections by the Food and Drug Administration, and cash shortages that seemed certain to flatline the company. As a startup, Cyberonics had no other product to supply revenue; the VNS device was its lone hope. "Since I've been CEO, our stock has dropped 50% or more on several occasions, we've had under $2 million in cash on three occasions, and we've seen major disappointments in almost every aspect of the business," says Skip Cummins, Cyberonics' current CEO and one of the venture capitalists who originally funded the company in 1987.