University of Sheffield researchers repair nerves with 3D printing

According to the University of Sheffield, damage to the trigeminal nerve – the nerve that connects the brain and parts of the face and mouth – can cause a range of symptoms from complete numbness to abnormal sensations, including tingling or burning in the tongue, lip, or chin. Some patients will experience unimaginable pain, whilst others have none.

The damage isn’t just physical. Patients who experience trigeminal nerve injury report severe quality-of-life issues. Numbness and pain in the affected areas can impact the ability to eat and speak, causing feelings of anxiety in patients about how they appear to the rest of the world. This can lead to depression, isolation, and damaged personal relationships – all caused by a visit to the dentist.

When neuroscience researchers and oral surgeons at the University of Sheffield’s School of Clinical Dentistry began developing treatments, it was understood that, in some circumstances, the nerve could be repaired, but the results were highly variable. “Surgical outcomes were very poor, leaving many patients with permanent life-altering injuries for which little treatment was offered,” said Dr. Simon Atkins, a Senior Clinical Lecturer and Consultant Oral Surgeon at the University of Sheffield, who leads the clinical repair service at Sheffield.

The neuroscience research team built a knowledge base from pre-clinical models designed to mimic the conditions treated in patients. Using this knowledge, the research team was able to establish a technique for repairing the nerve by removing damaged tissue and stitching the remaining nerve endings together. This technique produced better overall recovery than repair with either a nerve or muscle graft and proved successful in patients with moderate damage. However, for some, the area of damage was too large for the nerve ends to be rejoined.

Dr. Atkins, along with Professor Fiona Boissonade and Dr. Emma Bird, both from the School of Clinical Dentistry, are now researching ways to repair these more challenging nerves. “We’re working with the Professors Frederik Claeyssens and John Haycock from the Department of Material Science and Engineering to develop biocompatible materials that can be used to bridge larger gaps between nerve ends,” said Professor Boissonade. “We use 3D printing to accurately create a tubular structure out of the biocompatible material. By 3D printing, we can add features to the ‘tube’ that help to guide and enhance new growth of nerve fibres.”

That still leaves the question of why some patients experience pain but not others – and how to more effectively target pain in those who do feel it. “The pain patients feel ranges from slight tingling or burning to sharp stabbing pains, all of which can be devastating and have major impacts on their quality of life,” said Dr. Bird. The team is now using a unique archive of human tissue consisting of injured portions of the nerve removed at the time of nerve repair. Crucially, each sample is linked with a detailed pain history for the patient it comes from, including the presence and intensity of pain. It’s this history that’s providing new insight into the possible causes of pain. “The idea is to generate potential new treatments to reduce pain in those who experience it,” said Professor Boissonade. “We’re advancing our research, looking into how relevant molecules in and around the nerves might be influencing the amount of pain patients experience.”