When someone suffers an injury that results in a severed nerve, the usual treatment involves sewing the two severed ends directly back together, or bridging them by suturing in a nerve graft. Such repairs don't always function perfectly, however. What works better is to let the two ends grow back into each other. Scientists at the University of Sheffield have developed a means of helping them do so, in the form of a 3D-printed nerve guidance conduit (NGC).

An NGC is essentially just a tiny tube that the two nerve ends are fed into either end of. As they grow, they're guided towards one another, until they finally merge. Non-3D-printed NGCs are already sometimes used to repair damaged nerves, although because they're only available in a limited number of designs, their applications are limited.

The Sheffield researchers, however, have been using Computer Aided Design software to create customized NGCs, which are then built up via laser direct writing – this is a form of 3D printing in which a laser illuminates select sections of a photocurable resin, causing it to harden into a polymer (in this case, polyethylene glycol) in only those areas.

In lab tests on mice, the technology has already been used to successfully repair nerve injuries with an end-to-end gap of 3 mm, over the course of 21 days. The next steps are to look into the use of biodegradable materials, the ability to work over larger gaps, and to begin human trials.

According to the university, the 3D-printed NGCs "can be adapted for any type of nerve damage or even tailored to an individual patient."

A paper on the research was recently published in the journal Biomaterials.