* Procedure involved electrical stimulation of spinal cord

* Former baseball pitcher says procedure changed his life

NEW YORK - A man left paralyzed after a car accident was able to stand and take steps after electrical stimulation of his spinal cord in what researchers described as a breakthrough in treating such devastating injuries.

Rob Summers, a 25-year-old former college baseball pitcher, can also move his hips, knees, ankles and toes -- and has regained some bladder and sexual functionality, researchers said on Thursday.

"It opens up a huge opportunity to improve the daily functioning of these individuals ... but we have a long road ahead," said Susan Harkema, lead researcher of the study from the University of Louisville in Kentucky. The results were published in The Lancet medical journal.

"This is not a cure, and Rob's not walking. ... Short of that, this approach may have impact in incremental ways," she said. "Allowing people to just stand a few minutes a day can dramatically change their health."

Summers received continual direct electrical stimulation of the lower spinal cord, a process designed to mimic signals the brain normally transmits to initiate movement.

The researchers spent more than two years retraining Summers' spinal cord's neural networks to produce muscle movements, after which the electro-stimulation device was surgically implanted in his back.

The study's authors cautioned that more work needs to be done before the technique becomes standard practice.

But the results did herald optimism for paraplegics who otherwise have little hope for recovery. More than 5 million Americans live with some form of paralysis.

Harkema and her colleagues hope the finding will pave the way for some spinal cord patients, with the help of a portable stimulation unit, to stand and take steps using a walker.

IMPROVEMENT OF FUNCTION

Geoffrey Raisman, professor of neural regeneration at University College London, said the case was "interesting" but noted it "is not repair, but an improvement of function of tissue already surviving."

"From the point of view of people currently suffering from spinal cord injury, future trials of this procedure could add one more approach to getting some benefit," Raisman said in an e-mailed statement to Reuters.

The study was funded by the U.S. National Institutes of Health and the foundation named after Christopher Reeve, the actor best known for playing Superman who was left paralyzed after a riding accident. Reeve died in 2004.

A former Oregon State University pitcher, Summers was the victim of a hit-and-run accident in 2006 when he was 20 years old. He went to check on gym equipment in his car and was struck by another vehicle. The driver was never found.

Summers, while paralyzed below the chest, did retain some feeling below the level of his injury, making it uncertain how the treatment would fare with more severe patients who have lost all sensation. He was also an athlete when he got hurt and potentially in better physical shape that most such victims.

Summers spent more than three years in Kentucky preparing for surgery. He is now able to stand, supplying the muscular push himself, and remain standing while bearing weight for up to four minutes at a time.

With the help of a harness and assistance from a therapist, he can make repeated stepping motions on a treadmill.

Now a resident of Los Angeles, Summers said the procedure changed his life.

"For someone who for four years was unable to even move a toe, to have the freedom and ability to stand on my own is the most amazing feeling," Summers said. "My physique and muscle tone has improved greatly, so much that most people don't even believe I am paralyzed."