Charleston, West Virgina - It's no coincidence Charleston anesthesiologist Tim Deer was the first physician to implant the world's smallest rechargeable spinal cord stimulator in patients who suffer from chronic pain.

Dr. Deer, a pain medicine specialist with St. Francis Hospital, helped to develop and test the silver-dollar-size medical device over the past five years.

"It's like a pacemaker for the spine," Deer explained. "I have the ideas, the engineers make it work."

Deer plans to implant three people with the neurostimulator - called the Eon Mini - today. Earlier this week, Deer put the device in four patients, including a man who suffered chronic pain after a skydiving accident.

An official with the U.S. Food and Drug Administration watched Deer implant the devices at St. Francis' one-day surgery center. The FDA approved the Eon Mini four months ago, but continues to monitor the initial implants.

"They all went very well," Deer said. "No problems at all."

The spinal cord stimulator - manufactured by St. Jude Medical Inc. of St. Paul, Minn. - is used to treat pain in patients from failed back surgery, and chronic pain of the trunk and limbs.

Deer's patients include those with diabetes, shingles and radiation damage from cancer treatment.

The nerve stimulator, which costs about $15,000 and another $5,000 to implant, helps 60 percent to 90 percent of patients with certain types of chronic pain, according to initial studies.

Spinal cord stimulators have helped relieve pain since 1967. They deliver mild electrical impulses to the spinal cord, masking the transmission of pain signals to the brain.