The Food and Drug Administration on Wednesday approved a medical device tested about five years ago on actor Christopher Reeve to help him breathe without a ventilator. The implantable device, called NeuRx DPS RA/4 Respiratory Stimulation System and developed by Synapse Biomedical Inc. of Oberlin, Ohio, electrically stimulates the muscles and nerves that run through the diaphragm. It allows some spinal cord injury patients to breathe for at least four hours a day without a mechanical ventilator. Reeve was paralyzed from the neck down in a horseback riding accident in 1995. The "Superman" star received the experimental device in 2003 and could breathe off a ventilator for about 15 minutes while using it. He died in 2004.

"While the NeuRx RA/4 does not cure paralysis of the diaphragm, allowing patients to be free from a mechanical ventilator for at least four hours a day may enhance their quality of life," said Dr. Daniel Schultz, director of the FDA's Center for Devices and Radiological Health.

Spinal cord injuries can affect the muscles of the chest and abdomen, including the diaphragm, which is a lower abdominal muscle essential for breathing.

Normally, a person inhales when the diaphragm contracts and the lungs expand with air and a person exhales when the diaphragm relaxes and the air flows back out of the lungs.

The stimulation device uses four electrodes implanted in the muscle of the diaphragm to stimulate contraction.

The FDA approved the distribution of the stimulation system under a Humanitarian Device Exemption, an approval process for medical devices intended to treat or diagnose conditions that affect fewer than 4,000 people per year.