Thursday, February 07, 2008

Could a Spinal "Bypass" Reverse Paralysis?

A breakthrough in spinal surgery yesterday offered hope to victims of paralysis.

The technique, which has been tested on rats, involves bypassing damaged tissue in the spine.

This allows signals to travel across injured areas, New Scientist reports.

Dr John Martin and his colleagues at Columbia University in New York have so far tested the procedure only on rodents. They selected a motor nerve branching from the healthy cord above the injury and cut it away from the abdominal muscle to which it is normally attached.

They then stretched the free end across the injured section of spinal cord and used a protein "glue" to fix it.

Two weeks later the team found that the graft had sprouted new extensions which had begun to form connections - or synapses - with the motor nerves in the isolated lower spine.

Zapping the spinal cord above the injury made the lower limbs of the rats twitch - showing motor signals had started once again to pass along the entire length of the spine.

The researchers say removing the nerve from the abdominal muscle did not appear to cause any major side effects and suggest this is because nearby nerves pick up the slack.

Fellow neuroscientist Dr Reggie Edgerton, of California University, said the approach had considerable clinical potential but added that it was too early to tell whether it would work in humans.

Dr Marie Filbin of the City University of New York cautioned that it may not be possible to "reprogramme" a nerve that normally connects to an abdominal muscle to transmit the sophisticated signals needed to produce fine, controlled movements.

But Dr Martin, who presented his study at the New York State Spinal Cord Injury Research Program Symposium, said: "What we want to do is plug in new connections to bypass the damaged region."

He believes that - with a little surgical assistance - spinal cord nerves above an injury could be capable of making such connections with nerves lower down the spine.

He said: "We know the nerves can make new connections to muscle so we asked whether it's possible for them to also connect with spinal cord neurons isolated through injury."

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