Tied with stroke, spinal cord injury is the most common cause of adult paralysis, with four thousand new cases reported annually in the UK alone. Under normal circumstances, our brain controls the movement of our muscles by transmitting a complex set of electrical instructions through a vast network of nerve cells. However, damage to the spine can delay or stop these messages entirely, making movement harder or preventing it completely in the worst cases. Over the past few years, there has been a buzz of activity in the news reporting on cases of spinal cord injury being treated with exotic new implants or assistive exoskeletons. We need only look to popular culture to see how important this issue is to our collective psyche – the impact of paralysis and potential technological solutions is a frequently explored pop-culture trope. Often our fictional depictions of the future (both utopic, and perhaps more realistic) employ the theme of technology restoring movement to those with paralysis – for example, Jake Sully of Avatar fame transfers bodies entirely to get around this issue.
From a more practical perspective, a growing understanding of the nervous system and improved computational ability over the past thirty years has led to a blossoming of prosthetic advances in spinal injury healthcare. One particularly promising option is the “Implanted Pulse Generator”. A small machine implanted in the body that does the job of the injured spinal cord – reading and processing the electrical signals that allow our body to move, and transmitting them to the relevant muscles which otherwise wouldn’t be getting the instructions that they should.
The concept of a treatment that promises to restore spinal function is an old idea. Ancient myths and early prosthetic devices hint at humanity’s long-standing desire to lessen the impact of disability using technology. One particularly famous case is Hephaestus. One of Zeus’ many children, and the Greek god of fire and blacksmithing, he designed various machines to counteract his disability. In experimental terms however, it remains relatively young. Despite the potential to help individuals regain vital independence over their lives – the long-term efficacy of these solutions is still unknown.
A team at Case Western Reserve University, Ohio, has taken this challenge of lasting therapeutic impact onboard, recently publishing the results of a long-term study exploring patient outcomes over 25 years. When trying to answer if spinal cord injury can be treated over the long-term, the most difficult aspect is in fact defining the question in the first place. There are many ways a treatment can fail and therefore many challenges in how we define “good function” or a “positive treatment outcome”. To simplify their approach, they chose to combine many different patient outcomes such as rates of infection, electrical device function, and susceptibility to external device damage as a single “device survival value”. They found that most implanted devices (65%) remained perfectly functional even after multiple years of continuous operation. Of the treatments that failed, the most common cause was mechanical damage, either down to internal faults, or external trauma to the devices. Thankfully, all of the devices that failed were able to be replaced successfully. Device failure is not the only factor to consider moving forwards however, infection was also reported as a common side effect during treatment meaning patients had to come in for additional monitoring or antibiotics.
A better understanding of the limitations of these devices is vital if we are to perfect them and truly improve the mobility, and lives, of those with paralysis. While 65% device function is promising, the need for follow up surgery if something fails or bacterial infection arises, remains a key area of concern for patients who would have to go under the knife, or risk antibiotic resistance. However, results like this are nothing to be sneezed at. As materials science and technology improve, so too do the possible solutions to these challenges. Stronger device designs and the potential for infection resistant materials take us closer to a device that is functional, efficient, and safe – a dream come true for those with paralysis. The prospect of a future where spinal cord damage is just another treatable injury is on the horizon.
Article written by Aidan McConnell-Trevillion, a Neuroprosthetics PhD student at The University of Edinburgh, who specialises in computational approaches to systems neuroscience using machine learning techniques.
Article edited by Eleanor Stamp, a Neuroscience PhD student at the Institute of Genetics and Cancer, University of Edinburgh, and an Online News Editor for EUSci.
Resources:
Leapo et al. (2025) – Neuroprostheses: A 25-Year Review, Neuromodulation: Technology at the Neural Interface: https://www.sciencedirect.com/science/article/pii/S1094715924000709?CMX_ID=&SIS_ID=&dgcid=STMJ_253422_AUTSERV_OTR&utm_acid=115590209&utm_campaign=STMJ_253422_AUTSERV_OTR&utm_in=DM538257&utm_medium=email&utm_source=AC_
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