Damaged nerves regrown with new implant

British and German engineers have created computer-generated implants that allow damaged nerves to regrow.

The technique improves the chances of restoring sensation and movement in injured limbs, they say.

The new type of nerve guidance conduits, or NGC, is produced by laser direct writing, which allows complex structures to be fabricated via computer aided design/manufacturing (CAD/CAM).

Currently, the usual treatment for severe traumatic nerve damage is to surgically suture or graft the nerve endings together; but this often fails to work.

“When nerves in the arms or legs are injured they have the ability to regrow, unlike in the spinal cord; however, they need assistance to do this,” says University of Sheffield professor of bioengineering John Haycock.

“We are designing scaffold implants that can bridge an injury site and provide a range of physical and chemical cues for stimulating this regrowth.”

The new conduit is made from a biodegradable synthetic polymer material based on polylactic acid, and guides the damaged nerves to regrow through a number of small channels.

“Nerves aren’t just like one long cable, they’re made up of lots of small cables, similar to how an electrical wire is constructed,” says Sheffield’s Dr Frederik Claeyssens.

“Using our new technique we can make a conduit with individual strands, so the nerve fibres can form a similar structure to an undamaged nerve.”

Once the nerve is fully regrown, the conduit biodegrades naturally.

In lab experiments, nerve cells added to the polymer conduit grew naturally within the structure. The team’s now working towards clinical trials.

“If successful, we anticipate these scaffolds will not just be applicable to peripheral nerve injury, but could also be developed for other types of nerve damage too,” says Claeyssens.

“The technique of laser direct writing may ultimately allow production of scaffolds that could help in the treatment of spinal cord injury.”