SAN FRANCISCO -- Thirty-five million Americans suffer from migraines and chronic headaches. The pain can be so intense it immobilizes them, bringing their world to a standstill. Now, doctors are replacing medicine with a device that could shock the pain away.

"The headaches were so debilitating that it was like, you could remove my head if you want to at this point," migraine sufferer Judy Caletti said. "Just get them to stop."

When medication doesn't help chronic headaches, some doctors turn to an implantable nerve stimulator. The rechargeable battery powered electrode is about the size of a match stick. It's implanted near the occipital nerve in the back of the head.

"Occipital nerve stimulation works by activating nerves at the back of the head that then feed into the brain and change the way the brain behaves, in terms of responses to head pain signals," Peter Goadsby, M.D., Ph.D., a neurologist at the UCSF Headache Center in San Francisco, Calif., said.

The stimulator can be turned off and on with a remote control.

"When you turn the stimulators off, as we did deliberately for this study, the headache comes back," Dr. Goadsby said.

After six months, five out of six patients reported less pain -- some up to 95 percent less.

"The ability to be able to take a person whose life is more or less ruined by the headache problem and make a real difference … is one of the real excitements that drive me to work," Dr. Goadsby said.

And for many migraine suffers, the idea of getting rid of the pain without the side effects of medicine is a relief.

Dr. Goadsby says the procedure to implant the device carries a risk of infection. The nerve stimulator is also being used in pain management of osteoarthritis. The device is recharged using a special headband worn by the patient.